sshfs.c

/*
  SSH file system
  Copyright (C) 2004  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#define _GNU_SOURCE /* avoid implicit declaration of *pt* functions */
#include "config.h"

#include <fuse.h>
#include <fuse_opt.h>
#if !defined(__CYGWIN__)
#  include <fuse_lowlevel.h>
#endif
#ifdef __APPLE__
#  include <fuse_darwin.h>
#endif
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#ifndef __APPLE__
#  include <semaphore.h>
#endif
#include <pthread.h>
#include <netdb.h>
#include <signal.h>
#include <sys/uio.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <sys/mman.h>
#include <poll.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <glib.h>
#include <pwd.h>
#include <grp.h>
#include <limits.h>
#ifdef __APPLE__
#  include <strings.h>
#  include <libgen.h>
#  include <darwin_compat.h>
#endif
#ifdef __linux__
#  include <linux/vm_sockets.h>
#endif

#include "cache.h"

#ifndef MAP_LOCKED
#  define MAP_LOCKED 0
#endif

#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#  define MAP_ANONYMOUS MAP_ANON
#endif


#define SSH_FXP_INIT                1
#define SSH_FXP_VERSION             2
#define SSH_FXP_OPEN                3
#define SSH_FXP_CLOSE               4
#define SSH_FXP_READ                5
#define SSH_FXP_WRITE               6
#define SSH_FXP_LSTAT               7
#define SSH_FXP_FSTAT               8
#define SSH_FXP_SETSTAT             9
#define SSH_FXP_FSETSTAT           10
#define SSH_FXP_OPENDIR            11
#define SSH_FXP_READDIR            12
#define SSH_FXP_REMOVE             13
#define SSH_FXP_MKDIR              14
#define SSH_FXP_RMDIR              15
#define SSH_FXP_REALPATH           16
#define SSH_FXP_STAT               17
#define SSH_FXP_RENAME             18
#define SSH_FXP_READLINK           19
#define SSH_FXP_SYMLINK            20
#define SSH_FXP_STATUS            101
#define SSH_FXP_HANDLE            102
#define SSH_FXP_DATA              103
#define SSH_FXP_NAME              104
#define SSH_FXP_ATTRS             105
#define SSH_FXP_EXTENDED          200
#define SSH_FXP_EXTENDED_REPLY    201

#define SSH_FILEXFER_ATTR_SIZE          0x00000001
#define SSH_FILEXFER_ATTR_UIDGID        0x00000002
#define SSH_FILEXFER_ATTR_PERMISSIONS   0x00000004
#define SSH_FILEXFER_ATTR_ACMODTIME     0x00000008
#define SSH_FILEXFER_ATTR_EXTENDED      0x80000000

#define SSH_FX_OK                            0
#define SSH_FX_EOF                           1
#define SSH_FX_NO_SUCH_FILE                  2
#define SSH_FX_PERMISSION_DENIED             3
#define SSH_FX_FAILURE                       4
#define SSH_FX_BAD_MESSAGE                   5
#define SSH_FX_NO_CONNECTION                 6
#define SSH_FX_CONNECTION_LOST               7
#define SSH_FX_OP_UNSUPPORTED                8

#define SSH_FXF_READ            0x00000001
#define SSH_FXF_WRITE           0x00000002
#define SSH_FXF_APPEND          0x00000004
#define SSH_FXF_CREAT           0x00000008
#define SSH_FXF_TRUNC           0x00000010
#define SSH_FXF_EXCL            0x00000020

/* statvfs@openssh.com f_flag flags */
#define SSH2_FXE_STATVFS_ST_RDONLY	0x00000001
#define SSH2_FXE_STATVFS_ST_NOSUID	0x00000002

#define SFTP_EXT_POSIX_RENAME "posix-rename@openssh.com"
#define SFTP_EXT_STATVFS "statvfs@openssh.com"
#define SFTP_EXT_HARDLINK "hardlink@openssh.com"
#define SFTP_EXT_FSYNC "fsync@openssh.com"

#define PROTO_VERSION 3

#define MY_EOF 1

#define MAX_REPLY_LEN (1 << 17)

#define RENAME_TEMP_CHARS 8

#define SFTP_SERVER_PATH "/usr/lib/sftp-server"

/* Asynchronous readdir parameters */
#define READDIR_START 2
#define READDIR_MAX 32

#define MAX_PASSWORD 1024

/*
   Handling of multiple SFTP connections
   --------------------------------------

   An SFTP server is free to return responses to outstanding requests in arbitrary
   order. However, execution of requests may only be re-ordered and parallelized as long
   as "the results in the responses will be the same as if [the client] had sent the
   requests one at a time and waited for the response in each case".
   (https://tools.ietf.org/html/draft-ietf-secsh-filexfer-02#section-6.1).

   When using multiple connections, this requirement applies independently for each
   connection. We therefore have to make sure in SSHFS that the way in which we distribute
   requests between connections does not affect the responses that we get.

   In general, this is a tricky problem to solve since for each incoming request we have
   to determine which other in-flight requests may interact with it, and then either
   transmit the request through the same connection or (if there are multiple connections
   involved) wait for the other requests to complete. This means that e.g. a readdir
   request would have to block on most other activity in the same directory, eliminating a
   major advantage of using multiple connections.

   In practice, we can luckily take advantage of the knowledge that most FUSE requests are
   the result of (synchronous) syscalls from userspace that will block until the
   corresponding FUSE response has been sent.

   If -o sshfs_sync is used, SSHFS always waits for the SFTP server response before
   returning a FUSE response to userspace. If userspace makes concurrent system calls,
   there is no ordering guarantee in the first place, so we do not have to worry about
   (re-)ordering within SSHFS either.

   For requests that originate in the kernel (rather than userspace), the situation is
   slightly different. Transmission of FUSE requests and responses is decoupled (there are
   no synchronous calls) and there is no formal specification that defines if reordering
   is permitted. However, the Linux kernel seems to avoid submitting any concurrent
   requests that would give different results depending on execution order and (as of
   kernel 4.20 with writeback caching disabled) the only kind of kernel originated
   requests are read() requests for read-ahead. Since libfuse internally uses multiple
   threads, SSHFS does not necessarily receive requests in the order in which they were
   sent by the kernel. Unless there is a major bug in FUSE, there is therefore no need to
   worry about correct sequencing of such calls even when using multiple SFTP connections.

   If -o sshfs_sync is *not* used, then write() syscalls will return to userspace before
   SSHFS has received responses from the SFTP server. If userspace then issues a second
   syscall related to the same file (and only one connection is in-use), SFTP ordering
   guarantees will ensure that the response takes into account the preceding writes. If
   multiple connections are in use, this has to be ensured by SSHFS instead.

   The easiest way to do so would be to bind specific SFTP connections to file
   handles. Unfortunately, not all requests for the same dentry are guaranteed to come
   from the same file handle and some requests may come without any file handle. We
   therefore maintain a separate mapping from currently open files to SFTP connections. If
   a request comes in for a path contained in sshfs.conntab and its result could be
   changed by a pending write() operation, it will always be executed with the
   associated SFTP connection.

   There are additional subtleties for requests that affect multiple paths.  For example,
   if both source and destination of a rename() request are currently open, which
   connection should be used?

   This problem is again hard in general, but solvable since we only have to worry about
   the effects of pending write() calls. For rename() and link(), it does not matter if a
   pending write is executed before or after the operation. For readdir(), it is possible
   that a pending write() will change the length of the file. However, SSHFS currently
   does not return attribute information for readdir(), so this does not pose problems
   either. Should SSHFS implement a readdirplus() handler (which provides file names and
   attributes) this is a problem that will need to be solved.
*/


#ifdef __APPLE__
   static char sshfs_program_path[PATH_MAX] = { 0 };
#endif /* __APPLE__ */

struct conn {
	pthread_mutex_t lock_write;
	int processing_thread_started;
	int rfd;
	int wfd;
	int connver;
	int req_count;
	int dir_count;
	int file_count;
};

struct buffer {
	uint8_t *p;
	size_t len;
	size_t size;
};

struct dir_handle {
	struct buffer buf;
	struct conn *conn;
};

struct list_head {
	struct list_head *prev;
	struct list_head *next;
};

struct request;
typedef void (*request_func)(struct request *);

struct request {
	unsigned int want_reply;
	sem_t ready;
	uint8_t reply_type;
	uint32_t id;
	int replied;
	int error;
	struct buffer reply;
	struct timeval start;
	void *data;
	request_func end_func;
	size_t len;
	struct list_head list;
	struct conn *conn;
};

struct sshfs_io {
	int num_reqs;
	pthread_cond_t finished;
	int error;
};

struct read_req {
	struct sshfs_io *sio;
	struct list_head list;
	struct buffer data;
	size_t size;
	ssize_t res;
};

struct read_chunk {
	off_t offset;
	size_t size;
	int refs;
	long modifver;
	struct list_head reqs;
	struct sshfs_io sio;
};

struct sshfs_file {
	struct buffer handle;
	struct list_head write_reqs;
	pthread_cond_t write_finished;
	int write_error;
	struct read_chunk *readahead;
	off_t next_pos;
	int is_seq;
	struct conn *conn;
	int connver;
	int modifver;
};

struct conntab_entry {
	unsigned refcount;
	struct conn *conn;
};

struct sshfs {
	char *directport;
	char *ssh_command;
	char *sftp_server;
	struct fuse_args ssh_args;
	char *workarounds;
	int rename_workaround;
	int renamexdev_workaround;
	int truncate_workaround;
	int buflimit_workaround;
	int unrel_append;
	int fstat_workaround;
	int createmode_workaround;
	int transform_symlinks;
	int follow_symlinks;
	int no_check_root;
	int detect_uid;
	int idmap;
	int nomap;
	int disable_hardlink;
	int dir_cache;
	int show_version;
	int show_help;
	int singlethread;
	char *mountpoint;
	char *uid_file;
	char *gid_file;
	GHashTable *uid_map;
	GHashTable *gid_map;
	GHashTable *r_uid_map;
	GHashTable *r_gid_map;
	unsigned max_read;
	unsigned max_write;
	unsigned ssh_ver;
	int sync_write;
	int sync_read;
	int sync_readdir;
	int direct_io;
	int debug;
	int verbose;
	int foreground;
	int reconnect;
	int delay_connect;
	int passive;
	char *host;
	char *base_path;
	GHashTable *reqtab;
	GHashTable *conntab;
	pthread_mutex_t lock;
	unsigned int randseed;
	int max_conns;
	char *vsock;
	struct conn *conns;
	int ptyfd;
	int ptypassivefd;
	int connvers;
	int server_version;
	unsigned remote_uid;
	unsigned local_uid;
	unsigned remote_gid;
	unsigned local_gid;
	int remote_uid_detected;
	unsigned blksize;
	char *progname;
	long modifver;
	unsigned outstanding_len;
	unsigned max_outstanding_len;
	pthread_cond_t outstanding_cond;
	int password_stdin;
	char *password;
	int ext_posix_rename;
	int ext_statvfs;
	int ext_hardlink;
	int ext_fsync;
	struct fuse_operations *op;

	/* statistics */
	uint64_t bytes_sent;
	uint64_t bytes_received;
	uint64_t num_sent;
	uint64_t num_received;
	unsigned int min_rtt;
	unsigned int max_rtt;
	uint64_t total_rtt;
	unsigned int num_connect;
};

static struct sshfs sshfs;

static const char *ssh_opts[] = {
	"AddressFamily",
	"BatchMode",
	"BindAddress",
	"BindInterface",
	"CertificateFile",
	"ChallengeResponseAuthentication",
	"CheckHostIP",
	"Cipher",
	"Ciphers",
	"Compression",
	"CompressionLevel",
	"ConnectionAttempts",
	"ConnectTimeout",
	"ControlMaster",
	"ControlPath",
	"ControlPersist",
	"FingerprintHash",
	"GlobalKnownHostsFile",
	"GSSAPIAuthentication",
	"GSSAPIDelegateCredentials",
	"HostbasedAuthentication",
	"HostbasedKeyTypes",
	"HostKeyAlgorithms",
	"HostKeyAlias",
	"HostName",
	"IdentitiesOnly",
	"IdentityFile",
	"IdentityAgent",
	"IPQoS",
	"KbdInteractiveAuthentication",
	"KbdInteractiveDevices",
	"KexAlgorithms",
	"LocalCommand",
	"LogLevel",
	"MACs",
	"NoHostAuthenticationForLocalhost",
	"NumberOfPasswordPrompts",
	"PasswordAuthentication",
	"PermitLocalCommand",
	"PKCS11Provider",
	"Port",
	"PreferredAuthentications",
	"ProxyCommand",
	"ProxyJump",
	"ProxyUseFdpass",
	"PubkeyAcceptedKeyTypes",
	"PubkeyAuthentication",
	"RekeyLimit",
	"RevokedHostKeys",
	"RhostsRSAAuthentication",
	"RSAAuthentication",
	"ServerAliveCountMax",
	"ServerAliveInterval",
	"SmartcardDevice",
	"StrictHostKeyChecking",
	"TCPKeepAlive",
	"UpdateHostKeys",
	"UsePrivilegedPort",
	"UserKnownHostsFile",
	"VerifyHostKeyDNS",
	"VisualHostKey",
	NULL,
};

enum {
	KEY_PORT,
	KEY_COMPRESS,
	KEY_CONFIGFILE,
};

enum {
	IDMAP_NONE,
	IDMAP_USER,
	IDMAP_FILE,
};

enum {
	NOMAP_IGNORE,
	NOMAP_ERROR,
};

#define SSHFS_OPT(t, p, v) { t, offsetof(struct sshfs, p), v }

static struct fuse_opt sshfs_opts[] = {
	SSHFS_OPT("directport=%s",     directport, 0),
	SSHFS_OPT("ssh_command=%s",    ssh_command, 0),
	SSHFS_OPT("sftp_server=%s",    sftp_server, 0),
	SSHFS_OPT("max_read=%u",       max_read, 0),
	SSHFS_OPT("max_write=%u",      max_write, 0),
	SSHFS_OPT("ssh_protocol=%u",   ssh_ver, 0),
	SSHFS_OPT("-1",                ssh_ver, 1),
	SSHFS_OPT("workaround=%s",     workarounds, 0),
	SSHFS_OPT("idmap=none",        idmap, IDMAP_NONE),
	SSHFS_OPT("idmap=user",        idmap, IDMAP_USER),
	SSHFS_OPT("idmap=file",        idmap, IDMAP_FILE),
	SSHFS_OPT("uidfile=%s",        uid_file, 0),
	SSHFS_OPT("gidfile=%s",        gid_file, 0),
	SSHFS_OPT("nomap=ignore",      nomap, NOMAP_IGNORE),
	SSHFS_OPT("nomap=error",       nomap, NOMAP_ERROR),
	SSHFS_OPT("sshfs_sync",        sync_write, 1),
	SSHFS_OPT("no_readahead",      sync_read, 1),
	SSHFS_OPT("sync_readdir",      sync_readdir, 1),
	SSHFS_OPT("sshfs_debug",       debug, 1),
	SSHFS_OPT("sshfs_verbose",     verbose, 1),
	SSHFS_OPT("reconnect",         reconnect, 1),
	SSHFS_OPT("transform_symlinks", transform_symlinks, 1),
	SSHFS_OPT("follow_symlinks",   follow_symlinks, 1),
	SSHFS_OPT("no_check_root",     no_check_root, 1),
	SSHFS_OPT("password_stdin",    password_stdin, 1),
	SSHFS_OPT("delay_connect",     delay_connect, 1),
	SSHFS_OPT("slave",             passive, 1),
	SSHFS_OPT("passive",           passive, 1),
	SSHFS_OPT("disable_hardlink",  disable_hardlink, 1),
	SSHFS_OPT("dir_cache=yes", dir_cache, 1),
	SSHFS_OPT("dir_cache=no",  dir_cache, 0),
	SSHFS_OPT("direct_io",  direct_io, 1),
	SSHFS_OPT("max_conns=%u",  max_conns, 1),
	SSHFS_OPT("vsock=%s",      vsock, 0),

	SSHFS_OPT("-h",		show_help, 1),
	SSHFS_OPT("--help",	show_help, 1),
	SSHFS_OPT("-V",		show_version, 1),
	SSHFS_OPT("--version",	show_version, 1),
	SSHFS_OPT("-d",		debug, 1),
	SSHFS_OPT("debug",	debug, 1),
	SSHFS_OPT("-v",		verbose, 1),
	SSHFS_OPT("verbose",	verbose, 1),
	SSHFS_OPT("-f",		foreground, 1),
	SSHFS_OPT("-s",		singlethread, 1),

	FUSE_OPT_KEY("-p ",            KEY_PORT),
	FUSE_OPT_KEY("-C",             KEY_COMPRESS),
	FUSE_OPT_KEY("-F ",            KEY_CONFIGFILE),

	/* For backwards compatibility */
	SSHFS_OPT("cache=yes", dir_cache, 1),
	SSHFS_OPT("cache=no",  dir_cache, 0),

	FUSE_OPT_KEY("writeback_cache=no", FUSE_OPT_KEY_DISCARD),
	FUSE_OPT_KEY("unreliable_append", FUSE_OPT_KEY_DISCARD),

	/* These may come in from /etc/fstab - we just ignore them */
	FUSE_OPT_KEY("auto", FUSE_OPT_KEY_DISCARD),
	FUSE_OPT_KEY("noauto", FUSE_OPT_KEY_DISCARD),
	FUSE_OPT_KEY("user", FUSE_OPT_KEY_DISCARD),
	FUSE_OPT_KEY("nouser", FUSE_OPT_KEY_DISCARD),
	FUSE_OPT_KEY("users", FUSE_OPT_KEY_DISCARD),
	FUSE_OPT_KEY("_netdev", FUSE_OPT_KEY_DISCARD),

	FUSE_OPT_END
};

static struct fuse_opt workaround_opts[] = {
	SSHFS_OPT("none",       rename_workaround, 0),
	SSHFS_OPT("none",       truncate_workaround, 0),
	SSHFS_OPT("none",       buflimit_workaround, 0),
	SSHFS_OPT("none",       fstat_workaround, 0),
	SSHFS_OPT("rename",     rename_workaround, 1),
	SSHFS_OPT("norename",   rename_workaround, 0),
	SSHFS_OPT("renamexdev",   renamexdev_workaround, 1),
	SSHFS_OPT("norenamexdev", renamexdev_workaround, 0),
	SSHFS_OPT("truncate",   truncate_workaround, 1),
	SSHFS_OPT("notruncate", truncate_workaround, 0),
	SSHFS_OPT("buflimit",   buflimit_workaround, 1),
	SSHFS_OPT("nobuflimit", buflimit_workaround, 0),
	SSHFS_OPT("fstat",      fstat_workaround, 1),
	SSHFS_OPT("nofstat",    fstat_workaround, 0),
	SSHFS_OPT("createmode",   createmode_workaround, 1),
	SSHFS_OPT("nocreatemode", createmode_workaround, 0),
	FUSE_OPT_END
};

#define DEBUG(format, args...)						\
	do { if (sshfs.debug) fprintf(stderr, format, args); } while(0)

static const char *type_name(uint8_t type)
{
	switch(type) {
	case SSH_FXP_INIT:           return "INIT";
	case SSH_FXP_VERSION:        return "VERSION";
	case SSH_FXP_OPEN:           return "OPEN";
	case SSH_FXP_CLOSE:          return "CLOSE";
	case SSH_FXP_READ:           return "READ";
	case SSH_FXP_WRITE:          return "WRITE";
	case SSH_FXP_LSTAT:          return "LSTAT";
	case SSH_FXP_FSTAT:          return "FSTAT";
	case SSH_FXP_SETSTAT:        return "SETSTAT";
	case SSH_FXP_FSETSTAT:       return "FSETSTAT";
	case SSH_FXP_OPENDIR:        return "OPENDIR";
	case SSH_FXP_READDIR:        return "READDIR";
	case SSH_FXP_REMOVE:         return "REMOVE";
	case SSH_FXP_MKDIR:          return "MKDIR";
	case SSH_FXP_RMDIR:          return "RMDIR";
	case SSH_FXP_REALPATH:       return "REALPATH";
	case SSH_FXP_STAT:           return "STAT";
	case SSH_FXP_RENAME:         return "RENAME";
	case SSH_FXP_READLINK:       return "READLINK";
	case SSH_FXP_SYMLINK:        return "SYMLINK";
	case SSH_FXP_STATUS:         return "STATUS";
	case SSH_FXP_HANDLE:         return "HANDLE";
	case SSH_FXP_DATA:           return "DATA";
	case SSH_FXP_NAME:           return "NAME";
	case SSH_FXP_ATTRS:          return "ATTRS";
	case SSH_FXP_EXTENDED:       return "EXTENDED";
	case SSH_FXP_EXTENDED_REPLY: return "EXTENDED_REPLY";
	default:                     return "???";
	}
}

#define container_of(ptr, type, member) ({				\
			const typeof( ((type *)0)->member ) *__mptr = (ptr); \
			(type *)( (char *)__mptr - offsetof(type,member) );})

#define list_entry(ptr, type, member)		\
	container_of(ptr, type, member)

static void list_init(struct list_head *head)
{
	head->next = head;
	head->prev = head;
}

static void list_add(struct list_head *new, struct list_head *head)
{
	struct list_head *prev = head;
	struct list_head *next = head->next;
	next->prev = new;
	new->next = next;
	new->prev = prev;
	prev->next = new;
}

static void list_del(struct list_head *entry)
{
	struct list_head *prev = entry->prev;
	struct list_head *next = entry->next;
	next->prev = prev;
	prev->next = next;

}

static int list_empty(const struct list_head *head)
{
	return head->next == head;
}

/* given a pointer to the uid/gid, and the mapping table, remap the
 * uid/gid, if necessary */
static inline int translate_id(uint32_t *id, GHashTable *map)
{
	gpointer id_p;
	if (g_hash_table_lookup_extended(map, GUINT_TO_POINTER(*id), NULL, &id_p)) {
		*id = GPOINTER_TO_UINT(id_p);
		return 0;
	}
	switch (sshfs.nomap) {
	case NOMAP_ERROR: return -1;
	case NOMAP_IGNORE: return 0;
	default:
		fprintf(stderr, "internal error\n");
		abort();
	}
}

static inline void buf_init(struct buffer *buf, size_t size)
{
	if (size) {
		buf->p = (uint8_t *) malloc(size);
		if (!buf->p) {
			fprintf(stderr, "sshfs: memory allocation failed\n");
			abort();
		}
	} else
		buf->p = NULL;
	buf->len = 0;
	buf->size = size;
}

static inline void buf_free(struct buffer *buf)
{
	free(buf->p);
}

static inline void buf_finish(struct buffer *buf)
{
	buf->len = buf->size;
}

static inline void buf_clear(struct buffer *buf)
{
	buf_free(buf);
	buf_init(buf, 0);
}

static void buf_resize(struct buffer *buf, size_t len)
{
	buf->size = (buf->len + len + 63) & ~31;
	buf->p = (uint8_t *) realloc(buf->p, buf->size);
	if (!buf->p) {
		fprintf(stderr, "sshfs: memory allocation failed\n");
		abort();
	}
}

static inline void buf_check_add(struct buffer *buf, size_t len)
{
	if (buf->len + len > buf->size)
		buf_resize(buf, len);
}

#define _buf_add_mem(b, d, l)			\
	buf_check_add(b, l);			\
	memcpy(b->p + b->len, d, l);		\
	b->len += l;


static inline void buf_add_mem(struct buffer *buf, const void *data,
                               size_t len)
{
	_buf_add_mem(buf, data, len);
}

static inline void buf_add_buf(struct buffer *buf, const struct buffer *bufa)
{
	_buf_add_mem(buf, bufa->p, bufa->len);
}

static inline void buf_add_uint8(struct buffer *buf, uint8_t val)
{
	_buf_add_mem(buf, &val, 1);
}

static inline void buf_add_uint32(struct buffer *buf, uint32_t val)
{
	uint32_t nval = htonl(val);
	_buf_add_mem(buf, &nval, 4);
}

static inline void buf_add_uint64(struct buffer *buf, uint64_t val)
{
	buf_add_uint32(buf, val >> 32);
	buf_add_uint32(buf, val & 0xffffffff);
}

static inline void buf_add_data(struct buffer *buf, const struct buffer *data)
{
	buf_add_uint32(buf, data->len);
	buf_add_mem(buf, data->p, data->len);
}

static inline void buf_add_string(struct buffer *buf, const char *str)
{
	struct buffer data;
	data.p = (uint8_t *) str;
	data.len = strlen(str);
	buf_add_data(buf, &data);
}

static inline void buf_add_path(struct buffer *buf, const char *path)
{
	char *realpath;

	if (sshfs.base_path[0]) {
		if (path[1]) {
			if (sshfs.base_path[strlen(sshfs.base_path)-1] != '/') {
				realpath = g_strdup_printf("%s/%s",
							   sshfs.base_path,
							   path + 1);
			} else {
				realpath = g_strdup_printf("%s%s",
							   sshfs.base_path,
							   path + 1);
			}
		} else {
			realpath = g_strdup(sshfs.base_path);
		}
	} else {
		if (path[1])
			realpath = g_strdup(path + 1);
		else
			realpath = g_strdup(".");
	}
	buf_add_string(buf, realpath);
	g_free(realpath);
}

static int buf_check_get(struct buffer *buf, size_t len)
{
	if (buf->len + len > buf->size) {
		fprintf(stderr, "buffer too short\n");
		return -1;
	} else
		return 0;
}

static inline int buf_get_mem(struct buffer *buf, void *data, size_t len)
{
	if (buf_check_get(buf, len) == -1)
		return -1;
	memcpy(data, buf->p + buf->len, len);
	buf->len += len;
	return 0;
}

static inline int buf_get_uint8(struct buffer *buf, uint8_t *val)
{
	return buf_get_mem(buf, val, 1);
}

static inline int buf_get_uint32(struct buffer *buf, uint32_t *val)
{
	uint32_t nval;
	if (buf_get_mem(buf, &nval, 4) == -1)
		return -1;
	*val = ntohl(nval);
	return 0;
}

static inline int buf_get_uint64(struct buffer *buf, uint64_t *val)
{
	uint32_t val1;
	uint32_t val2;
	if (buf_get_uint32(buf, &val1) == -1 ||
	    buf_get_uint32(buf, &val2) == -1) {
		return -1;
	}
	*val = ((uint64_t) val1 << 32) + val2;
	return 0;
}

static inline int buf_get_data(struct buffer *buf, struct buffer *data)
{
	uint32_t len;
	if (buf_get_uint32(buf, &len) == -1 || len > buf->size - buf->len)
		return -1;
	buf_init(data, len + 1);
	data->size = len;
	if (buf_get_mem(buf, data->p, data->size) == -1) {
		buf_free(data);
		return -1;
	}
	return 0;
}

static inline int buf_get_string(struct buffer *buf, char **str)
{
	struct buffer data;
	if (buf_get_data(buf, &data) == -1)
		return -1;
	data.p[data.size] = '\0';
	*str = (char *) data.p;
	return 0;
}

static int buf_get_attrs(struct buffer *buf, struct stat *stbuf, int *flagsp)
{
	uint32_t flags;
	uint64_t size = 0;
	uint32_t uid = 0;
	uint32_t gid = 0;
	uint32_t atime = 0;
	uint32_t mtime = 0;
	uint32_t mode = S_IFREG | 0777;

	if (buf_get_uint32(buf, &flags) == -1)
		return -EIO;
	if (flagsp)
		*flagsp = flags;
	if ((flags & SSH_FILEXFER_ATTR_SIZE) &&
	    buf_get_uint64(buf, &size) == -1)
		return -EIO;
	if ((flags & SSH_FILEXFER_ATTR_UIDGID) &&
	    (buf_get_uint32(buf, &uid) == -1 ||
	     buf_get_uint32(buf, &gid) == -1))
		return -EIO;
	if ((flags & SSH_FILEXFER_ATTR_PERMISSIONS) &&
	    buf_get_uint32(buf, &mode) == -1)
		return -EIO;
	if ((flags & SSH_FILEXFER_ATTR_ACMODTIME)) {
		if (buf_get_uint32(buf, &atime) == -1 ||
		    buf_get_uint32(buf, &mtime) == -1)
			return -EIO;
	}
	if ((flags & SSH_FILEXFER_ATTR_EXTENDED)) {
		uint32_t extcount;
		unsigned i;
		if (buf_get_uint32(buf, &extcount) == -1)
			return -EIO;
		for (i = 0; i < extcount; i++) {
			struct buffer tmp;
			if (buf_get_data(buf, &tmp) == -1)
				return -EIO;
			buf_free(&tmp);
			if (buf_get_data(buf, &tmp) == -1)
				return -EIO;
			buf_free(&tmp);
		}
	}

	if (sshfs.remote_uid_detected) {
		if (uid == sshfs.remote_uid)
			uid = sshfs.local_uid;
		if (gid == sshfs.remote_gid)
			gid = sshfs.local_gid;
	}
	if (sshfs.idmap == IDMAP_FILE && sshfs.uid_map)
		if (translate_id(&uid, sshfs.uid_map) == -1)
			return -EPERM;
	if (sshfs.idmap == IDMAP_FILE && sshfs.gid_map)
		if (translate_id(&gid, sshfs.gid_map) == -1)
			return -EPERM;

	memset(stbuf, 0, sizeof(struct stat));
	stbuf->st_mode = mode;
	stbuf->st_nlink = 1;
	stbuf->st_size = size;
	if (sshfs.blksize) {
		stbuf->st_blksize = sshfs.blksize;
		stbuf->st_blocks = ((size + sshfs.blksize - 1) &
			~((unsigned long long) sshfs.blksize - 1)) >> 9;
	}
	stbuf->st_uid = uid;
	stbuf->st_gid = gid;
	stbuf->st_atime = atime;
	stbuf->st_ctime = stbuf->st_mtime = mtime;
	return 0;
}

static int buf_get_statvfs(struct buffer *buf, struct statvfs *stbuf)
{
	uint64_t bsize;
	uint64_t frsize;
	uint64_t blocks;
	uint64_t bfree;
	uint64_t bavail;
	uint64_t files;
	uint64_t ffree;
	uint64_t favail;
	uint64_t fsid;
	uint64_t flag;
	uint64_t namemax;

	if (buf_get_uint64(buf, &bsize) == -1 ||
	    buf_get_uint64(buf, &frsize) == -1 ||
	    buf_get_uint64(buf, &blocks) == -1 ||
	    buf_get_uint64(buf, &bfree) == -1 ||
	    buf_get_uint64(buf, &bavail) == -1 ||
	    buf_get_uint64(buf, &files) == -1 ||
	    buf_get_uint64(buf, &ffree) == -1 ||
	    buf_get_uint64(buf, &favail) == -1 ||
	    buf_get_uint64(buf, &fsid) == -1 ||
	    buf_get_uint64(buf, &flag) == -1 ||
	    buf_get_uint64(buf, &namemax) == -1) {
		return -1;
	}

	memset(stbuf, 0, sizeof(struct statvfs));
	stbuf->f_bsize = bsize;
	stbuf->f_frsize = frsize;
	stbuf->f_blocks = blocks;
	stbuf->f_bfree = bfree;
	stbuf->f_bavail = bavail;
	stbuf->f_files = files;
	stbuf->f_ffree = ffree;
	stbuf->f_favail = favail;
	stbuf->f_namemax = namemax;

	return 0;
}

static int buf_get_entries(struct buffer *buf, void *dbuf,
                           fuse_fill_dir_t filler)
{
	uint32_t count;
	unsigned i;

	if (buf_get_uint32(buf, &count) == -1)
		return -EIO;

	for (i = 0; i < count; i++) {
		int err = -1;
		char *name;
		char *longname;
		struct stat stbuf;
		if (buf_get_string(buf, &name) == -1)
			return -EIO;
		if (buf_get_string(buf, &longname) != -1) {
			free(longname);
			err = buf_get_attrs(buf, &stbuf, NULL);
			if (!err) {
				if (sshfs.follow_symlinks &&
				    S_ISLNK(stbuf.st_mode)) {
					stbuf.st_mode = 0;
				}
				filler(dbuf, name, &stbuf, 0, 0);
			}
		}
		free(name);
		if (err)
			return err;
	}
	return 0;
}

static void ssh_add_arg(const char *arg)
{
	if (fuse_opt_add_arg(&sshfs.ssh_args, arg) == -1)
		_exit(1);
}


static int pty_expect_loop(struct conn *conn)
{
	int res;
	char buf[256];
	const char *passwd_str = "assword:";
	int timeout = 60 * 1000; /* 1min timeout for the prompt to appear */
	int passwd_len = strlen(passwd_str);
	int len = 0;
	char c;

	while (1) {
		struct pollfd fds[2];

		fds[0].fd = conn->rfd;
		fds[0].events = POLLIN;
		fds[1].fd = sshfs.ptyfd;
		fds[1].events = POLLIN;
		res = poll(fds, 2, timeout);
		if (res == -1) {
			perror("poll");
			return -1;
		}
		if (res == 0) {
			fprintf(stderr, "Timeout waiting for prompt\n");
			return -1;
		}
		if (fds[0].revents) {
			/*
			 * Something happened on stdout of ssh, this
			 * either means, that we are connected, or
			 * that we are disconnected.  In any case the
			 * password doesn't matter any more.
			 */
			break;
		}

		res = read(sshfs.ptyfd, &c, 1);
		if (res == -1) {
			perror("read");
			return -1;
		}
		if (res == 0) {
			fprintf(stderr, "EOF while waiting for prompt\n");
			return -1;
		}
		buf[len] = c;
		len++;
		if (len == passwd_len) {
			if (memcmp(buf, passwd_str, passwd_len) == 0) {
				write(sshfs.ptyfd, sshfs.password,
				      strlen(sshfs.password));
			}
			memmove(buf, buf + 1, passwd_len - 1);
			len--;
		}
	}

	if (!sshfs.reconnect) {
		size_t size = getpagesize();

		memset(sshfs.password, 0, size);
		munmap(sshfs.password, size);
		sshfs.password = NULL;
	}

	return 0;
}

static struct conn* get_conn(const struct sshfs_file *sf,
			     const char *path)
{
	struct conntab_entry *ce;
	int i;

	if (sshfs.max_conns == 1)
		return &sshfs.conns[0];

	if (sf != NULL)
		return sf->conn;

	if (path != NULL) {
		pthread_mutex_lock(&sshfs.lock);
		ce = g_hash_table_lookup(sshfs.conntab, path);

		if (ce != NULL) {
			struct conn *conn = ce->conn;
			pthread_mutex_unlock(&sshfs.lock);
			return conn;
		}
		pthread_mutex_unlock(&sshfs.lock);
	}

	int best_index = 0;
	uint64_t best_score = ~0ULL; /* smaller is better */
	for (i = 0; i < sshfs.max_conns; i++) {
		uint64_t score = ((uint64_t) sshfs.conns[i].req_count << 43) +
				 ((uint64_t) sshfs.conns[i].dir_count << 22) +
				 ((uint64_t) sshfs.conns[i].file_count << 1) +
				 (uint64_t) (sshfs.conns[i].rfd >= 0 ? 0 : 1);
		if (score < best_score) {
			best_index = i;
			best_score = score;
		}
	}
	return &sshfs.conns[best_index];
}

static int pty_master(char **name)
{
	int mfd;

	mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
	if (mfd == -1) {
		perror("failed to open pty");
		return -1;
	}
	if (grantpt(mfd) != 0) {
		perror("grantpt");
		return -1;
	}
	if (unlockpt(mfd) != 0) {
		perror("unlockpt");
		return -1;
	}
	*name = ptsname(mfd);

	return mfd;
}

static void replace_arg(char **argp, const char *newarg)
{
	free(*argp);
	*argp = strdup(newarg);
	if (*argp == NULL) {
		fprintf(stderr, "sshfs: memory allocation failed\n");
		abort();
	}
}

static int start_ssh(struct conn *conn)
{
	char *ptyname = NULL;
	int sockpair[2];
	int pid;

	if (sshfs.password_stdin) {

		sshfs.ptyfd = pty_master(&ptyname);
		if (sshfs.ptyfd == -1)
			return -1;

		sshfs.ptypassivefd = open(ptyname, O_RDWR | O_NOCTTY);
		if (sshfs.ptypassivefd == -1)
			return -1;
	}

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sockpair) == -1) {
		perror("failed to create socket pair");
		return -1;
	}
	conn->rfd = sockpair[0];
	conn->wfd = sockpair[0];

	pid = fork();
	if (pid == -1) {
		perror("failed to fork");
		close(sockpair[1]);
		return -1;
	} else if (pid == 0) {
		int devnull;

		devnull = open("/dev/null", O_WRONLY);

		if (dup2(sockpair[1], 0) == -1 || dup2(sockpair[1], 1) == -1) {
			perror("failed to redirect input/output");
			_exit(1);
		}
		if (!sshfs.verbose && !sshfs.foreground && devnull != -1)
			dup2(devnull, 2);

		close(devnull);
		close(sockpair[0]);
		close(sockpair[1]);

		switch (fork()) {
		case -1:
			perror("failed to fork");
			_exit(1);
		case 0:
			break;
		default:
			_exit(0);
		}
		chdir("/");
		/*
		 * Avoid processes hanging trying to stat() OLDPWD if it is in
		 * the mount point. This can be removed if sshfs opens the
		 * mount point after establishing the ssh connection.
		 */
		unsetenv("OLDPWD");

		if (sshfs.password_stdin) {
			int sfd;

			setsid();
			sfd = open(ptyname, O_RDWR);
			if (sfd == -1) {
				perror(ptyname);
				_exit(1);
			}
			close(sfd);
			close(sshfs.ptypassivefd);
			close(sshfs.ptyfd);
		}

		if (sshfs.debug) {
			int i;

			fprintf(stderr, "executing");
			for (i = 0; i < sshfs.ssh_args.argc; i++)
				fprintf(stderr, " <%s>",
					sshfs.ssh_args.argv[i]);
			fprintf(stderr, "\n");
		}

#if defined(__CYGWIN__)
		/* 
		 * Windows native OpenSSH stdio behavior. For details check
		 * https://github.com/PowerShell/openssh-portable/pull/759
		 */
		putenv("OPENSSH_STDIO_MODE=nonsock");
#endif
		execvp(sshfs.ssh_args.argv[0], sshfs.ssh_args.argv);
		fprintf(stderr, "failed to execute '%s': %s\n",
			sshfs.ssh_args.argv[0], strerror(errno));
		_exit(1);
	}
	waitpid(pid, NULL, 0);
	close(sockpair[1]);
	return 0;
}

static int connect_passive(struct conn *conn)
{
	conn->rfd = STDIN_FILENO;
	conn->wfd = STDOUT_FILENO;
	return 0;
}

static int connect_to(struct conn *conn, char *host, char *port)
{
	int err;
	int sock;
	int opt;
	struct addrinfo *ai;
	struct addrinfo hint;

	memset(&hint, 0, sizeof(hint));
	hint.ai_family = PF_INET;
	hint.ai_socktype = SOCK_STREAM;
	err = getaddrinfo(host, port, &hint, &ai);
	if (err) {
		fprintf(stderr, "failed to resolve %s:%s: %s\n", host, port,
			gai_strerror(err));
		return -1;
	}
	sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
	if (sock == -1) {
		perror("failed to create socket");
		freeaddrinfo(ai);
		return -1;
	}
	err = connect(sock, ai->ai_addr, ai->ai_addrlen);
	if (err == -1) {
		perror("failed to connect");
		freeaddrinfo(ai);
		close(sock);
		return -1;
	}
	opt = 1;
	err = setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
	if (err == -1)
		perror("warning: failed to set TCP_NODELAY");

	freeaddrinfo(ai);

	conn->rfd = sock;
	conn->wfd = sock;
	return 0;
}

static int connect_vsock(struct conn *conn, char *vsock)
{
#ifndef __linux__
	fprintf(stderr, "vsock is not available\n");
	return -1;
#else
	int err;
	int sock;
	struct sockaddr_vm addr;
	unsigned int cid;
	unsigned int port;
	char *delim;

	delim = strchr(vsock, ':');
	if (delim == NULL) {
		fprintf(stderr, "invalid vsock, expecting CID:PORT\n");
		return -1;
	}
	*delim = '\0';
	errno = 0;
	cid = strtoul(vsock, NULL, 10);
	if (errno) {
		perror("invalid cid");
		return -1;
	}
	errno = 0;
	port = strtoul(delim + 1, NULL, 10);
	if (errno) {
		perror("invalid port");
		return -1;
	}

	sock = socket(AF_VSOCK, SOCK_STREAM, 0);
	if (sock == -1) {
		perror("failed to create socket");
		return -1;
	}
	memset(&addr, 0, sizeof(addr));
	addr.svm_family = AF_VSOCK;
	addr.svm_cid = cid;
	addr.svm_port = port;
	err = connect(sock, (const struct sockaddr *)&addr, sizeof(addr));
	if (err == -1) {
		perror("failed to connect vsock");
		close(sock);
		return -1;
	}

	conn->rfd = sock;
	conn->wfd = sock;
	return 0;
#endif
}

static int do_write(struct conn *conn, struct iovec *iov, size_t count)
{
	int res;
	while (count) {
		res = writev(conn->wfd, iov, count);
		if (res == -1) {
			perror("write");
			return -1;
		} else if (res == 0) {
			fprintf(stderr, "zero write\n");
			return -1;
		}
		do {
			if ((unsigned) res < iov->iov_len) {
				iov->iov_len -= res;
				iov->iov_base += res;
				break;
			} else {
				res -= iov->iov_len;
				count --;
				iov ++;
			}
		} while(count);
	}
	return 0;
}

static uint32_t sftp_get_id(void)
{
	static uint32_t idctr;
	return idctr++;
}

static void buf_to_iov(const struct buffer *buf, struct iovec *iov)
{
	iov->iov_base = buf->p;
	iov->iov_len = buf->len;
}

static size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
{
	unsigned long seg;
	size_t ret = 0;

	for (seg = 0; seg < nr_segs; seg++)
		ret += iov[seg].iov_len;
	return ret;
}

#define SFTP_MAX_IOV 3

static int sftp_send_iov(struct conn *conn, uint8_t type, uint32_t id,
                         struct iovec iov[], size_t count)
{
	int res;
	struct buffer buf;
	struct iovec iovout[SFTP_MAX_IOV];
	unsigned i;
	unsigned nout = 0;

	assert(count <= SFTP_MAX_IOV - 1);
	buf_init(&buf, 9);
	buf_add_uint32(&buf, iov_length(iov, count) + 5);
	buf_add_uint8(&buf, type);
	buf_add_uint32(&buf, id);
	buf_to_iov(&buf, &iovout[nout++]);
	for (i = 0; i < count; i++)
		iovout[nout++] = iov[i];
	pthread_mutex_lock(&conn->lock_write);
	res = do_write(conn, iovout, nout);
	pthread_mutex_unlock(&conn->lock_write);
	buf_free(&buf);
	return res;
}

static int do_read(struct conn *conn, struct buffer *buf)
{
	int res;
	uint8_t *p = buf->p;
	size_t size = buf->size;
	while (size) {
		res = read(conn->rfd, p, size);
		if (res == -1) {
			perror("read");
			return -1;
		} else if (res == 0) {
			fprintf(stderr, "remote host has disconnected\n");
			return -1;
		}
		size -= res;
		p += res;
	}
	return 0;
}

static int sftp_read(struct conn *conn, uint8_t *type, struct buffer *buf)
{
	int res;
	struct buffer buf2;
	uint32_t len;
	buf_init(&buf2, 5);
	res = do_read(conn, &buf2);
	if (res != -1) {
		if (buf_get_uint32(&buf2, &len) == -1)
			return -1;
		if (len > MAX_REPLY_LEN) {
			fprintf(stderr, "reply len too large: %u\n", len);
			return -1;
		}
		if (buf_get_uint8(&buf2, type) == -1)
			return -1;
		buf_init(buf, len - 1);
		res = do_read(conn, buf);
	}
	buf_free(&buf2);
	return res;
}

static void request_free(struct request *req)
{
	if (req->end_func)
		req->end_func(req);

	req->conn->req_count--;

	buf_free(&req->reply);
	sem_destroy(&req->ready);
	g_free(req);
}

static void chunk_free(struct read_chunk *chunk)
{
	while (!list_empty(&chunk->reqs)) {
		struct read_req *rreq;

		rreq = list_entry(chunk->reqs.prev, struct read_req, list);
		list_del(&rreq->list);
		buf_free(&rreq->data);
		g_free(rreq);
	}
	g_free(chunk);
}

static void chunk_put(struct read_chunk *chunk)
{
	if (chunk) {
		chunk->refs--;
		if (!chunk->refs)
			chunk_free(chunk);
	}
}

static void chunk_put_locked(struct read_chunk *chunk)
{
	pthread_mutex_lock(&sshfs.lock);
	chunk_put(chunk);
	pthread_mutex_unlock(&sshfs.lock);
}

static int clean_req(void *key, struct request *req, gpointer user_data)
{
	(void) key;
	struct conn* conn = (struct conn*) user_data;

	if (req->conn != conn)
		return FALSE;

	req->error = -EIO;
	if (req->want_reply)
		sem_post(&req->ready);
	else
		request_free(req);

	return TRUE;
}

static int process_one_request(struct conn *conn)
{
	int res;
	struct buffer buf;
	uint8_t type;
	struct request *req;
	uint32_t id;

	buf_init(&buf, 0);
	res = sftp_read(conn, &type, &buf);
	if (res == -1)
		return -1;
	if (buf_get_uint32(&buf, &id) == -1)
		return -1;

	pthread_mutex_lock(&sshfs.lock);
	req = (struct request *)
		g_hash_table_lookup(sshfs.reqtab, GUINT_TO_POINTER(id));
	if (req == NULL)
		fprintf(stderr, "request %i not found\n", id);
	else {
		int was_over;

		was_over = sshfs.outstanding_len > sshfs.max_outstanding_len;
		sshfs.outstanding_len -= req->len;
		if (was_over &&
		    sshfs.outstanding_len <= sshfs.max_outstanding_len) {
			pthread_cond_broadcast(&sshfs.outstanding_cond);
		}
		g_hash_table_remove(sshfs.reqtab, GUINT_TO_POINTER(id));
	}
	pthread_mutex_unlock(&sshfs.lock);
	if (req != NULL) {
		if (sshfs.debug) {
			struct timeval now;
			unsigned int difftime;
			unsigned msgsize = buf.size + 5;

			gettimeofday(&now, NULL);
			difftime = (now.tv_sec - req->start.tv_sec) * 1000;
			difftime += (now.tv_usec - req->start.tv_usec) / 1000;
			DEBUG("  [%05i] %14s %8ubytes (%ims)\n", id,
			      type_name(type), msgsize, difftime);

			if (difftime < sshfs.min_rtt || !sshfs.num_received)
				sshfs.min_rtt = difftime;
			if (difftime > sshfs.max_rtt)
				sshfs.max_rtt = difftime;
			sshfs.total_rtt += difftime;
			sshfs.num_received++;
			sshfs.bytes_received += msgsize;
		}
		req->reply = buf;
		req->reply_type = type;
		req->replied = 1;
		if (req->want_reply)
			sem_post(&req->ready);
		else {
			pthread_mutex_lock(&sshfs.lock);
			request_free(req);
			pthread_mutex_unlock(&sshfs.lock);
		}
	} else
		buf_free(&buf);

	return 0;
}

static void close_conn(struct conn *conn)
{
	close(conn->rfd);
	if (conn->rfd != conn->wfd)
		close(conn->wfd);
	conn->rfd = -1;
	conn->wfd = -1;
	if (sshfs.ptyfd != -1) {
		close(sshfs.ptyfd);
		sshfs.ptyfd = -1;
	}
	if (sshfs.ptypassivefd != -1) {
		close(sshfs.ptypassivefd);
		sshfs.ptypassivefd = -1;
	}
}

static void *process_requests(void *data_)
{
	(void) data_;
	struct conn *conn = data_;

	while (1) {
		if (process_one_request(conn) == -1)
			break;
	}

	pthread_mutex_lock(&sshfs.lock);
	conn->processing_thread_started = 0;
	close_conn(conn);
	g_hash_table_foreach_remove(sshfs.reqtab, (GHRFunc) clean_req, conn);
	conn->connver = ++sshfs.connvers;
	sshfs.outstanding_len = 0;
	pthread_cond_broadcast(&sshfs.outstanding_cond);
	pthread_mutex_unlock(&sshfs.lock);

	if (!sshfs.reconnect) {
		/* harakiri */
		kill(getpid(), SIGTERM);
	}
	return NULL;
}

static int sftp_init_reply_ok(struct conn *conn, struct buffer *buf,
                              uint32_t *version)
{
	uint32_t len;
	uint8_t type;

	if (buf_get_uint32(buf, &len) == -1)
		return -1;

	if (len < 5 || len > MAX_REPLY_LEN)
		return 1;

	if (buf_get_uint8(buf, &type) == -1)
		return -1;

	if (type != SSH_FXP_VERSION)
		return 1;

	if (buf_get_uint32(buf, version) == -1)
		return -1;

	DEBUG("Server version: %u\n", *version);

	if (len > 5) {
		struct buffer buf2;

		buf_init(&buf2, len - 5);
		if (do_read(conn, &buf2) == -1) {
			buf_free(&buf2);
			return -1;
		}

		do {
			char *ext = NULL;
			char *extdata = NULL;

			if (buf_get_string(&buf2, &ext) == -1 ||
			    buf_get_string(&buf2, &extdata) == -1) {
				buf_free(&buf2);
				free(ext);
				free(extdata);
				return -1;
			}

			DEBUG("Extension: %s <%s>\n", ext, extdata);

			if (strcmp(ext, SFTP_EXT_POSIX_RENAME) == 0 &&
			    strcmp(extdata, "1") == 0) {
				sshfs.ext_posix_rename = 1;
				sshfs.rename_workaround = 0;
			}
			if (strcmp(ext, SFTP_EXT_STATVFS) == 0 &&
			    strcmp(extdata, "2") == 0)
				sshfs.ext_statvfs = 1;
			if (strcmp(ext, SFTP_EXT_HARDLINK) == 0 &&
			    strcmp(extdata, "1") == 0)
				sshfs.ext_hardlink = 1;
			if (strcmp(ext, SFTP_EXT_FSYNC) == 0 &&
			    strcmp(extdata, "1") == 0)
				sshfs.ext_fsync = 1;

			free(ext);
			free(extdata);
		} while (buf2.len < buf2.size);
		buf_free(&buf2);
	}
	return 0;
}

static int sftp_find_init_reply(struct conn *conn, uint32_t *version)
{
	int res;
	struct buffer buf;

	buf_init(&buf, 9);
	res = do_read(conn, &buf);
	while (res != -1) {
		struct buffer buf2;

		res = sftp_init_reply_ok(conn, &buf, version);
		if (res <= 0)
			break;

		/* Iterate over any rubbish until the version reply is found */
		DEBUG("%c", *buf.p);
		memmove(buf.p, buf.p + 1, buf.size - 1);
		buf.len = 0;
		buf2.p = buf.p + buf.size - 1;
		buf2.size = 1;
		res = do_read(conn, &buf2);
	}
	buf_free(&buf);
	return res;
}

static int sftp_init(struct conn *conn)
{
	int res = -1;
	uint32_t version = 0;
	struct buffer buf;
	buf_init(&buf, 0);
	if (sftp_send_iov(conn, SSH_FXP_INIT, PROTO_VERSION, NULL, 0) == -1)
		goto out;

	if (sshfs.password_stdin && pty_expect_loop(conn) == -1)
		goto out;

	if (sftp_find_init_reply(conn, &version) == -1)
		goto out;

	sshfs.server_version = version;
	if (version > PROTO_VERSION) {
		fprintf(stderr,
			"Warning: server uses version: %i, we support: %i\n",
			version, PROTO_VERSION);
	}
	res = 0;

out:
	buf_free(&buf);
	return res;
}

static int sftp_error_to_errno(uint32_t error)
{
	switch (error) {
	case SSH_FX_OK:                return 0;
	case SSH_FX_NO_SUCH_FILE:      return ENOENT;
	case SSH_FX_PERMISSION_DENIED: return EACCES;
	case SSH_FX_FAILURE:           return EPERM;
	case SSH_FX_BAD_MESSAGE:       return EBADMSG;
	case SSH_FX_NO_CONNECTION:     return ENOTCONN;
	case SSH_FX_CONNECTION_LOST:   return ECONNABORTED;
	case SSH_FX_OP_UNSUPPORTED:    return EOPNOTSUPP;
	default:                       return EIO;
	}
}

static void sftp_detect_uid(struct conn *conn)
{
	int flags;
	uint32_t id = sftp_get_id();
	uint32_t replid;
	uint8_t type;
	struct buffer buf;
	struct stat stbuf;
	struct iovec iov[1];

	buf_init(&buf, 5);
	buf_add_string(&buf, ".");
	buf_to_iov(&buf, &iov[0]);
	if (sftp_send_iov(conn, SSH_FXP_STAT, id, iov, 1) == -1)
		goto out;
	buf_clear(&buf);
	if (sftp_read(conn, &type, &buf) == -1)
		goto out;
	if (type != SSH_FXP_ATTRS && type != SSH_FXP_STATUS) {
		fprintf(stderr, "protocol error\n");
		goto out;
	}
	if (buf_get_uint32(&buf, &replid) == -1)
		goto out;
	if (replid != id) {
		fprintf(stderr, "bad reply ID\n");
		goto out;
	}
	if (type == SSH_FXP_STATUS) {
		uint32_t serr;
		if (buf_get_uint32(&buf, &serr) == -1)
			goto out;

		fprintf(stderr, "failed to stat home directory (%i)\n", serr);
		goto out;
	}
	if (buf_get_attrs(&buf, &stbuf, &flags) != 0)
		goto out;

	if (!(flags & SSH_FILEXFER_ATTR_UIDGID))
		goto out;

	sshfs.remote_uid = stbuf.st_uid;
	sshfs.local_uid = getuid();
	sshfs.remote_gid = stbuf.st_gid;
	sshfs.local_gid = getgid();
	sshfs.remote_uid_detected = 1;
	DEBUG("remote_uid = %i\n", sshfs.remote_uid);

out:
	if (!sshfs.remote_uid_detected)
		fprintf(stderr, "failed to detect remote user ID\n");

	buf_free(&buf);
}

static int sftp_check_root(struct conn *conn, const char *base_path)
{
	int flags;
	uint32_t id = sftp_get_id();
	uint32_t replid;
	uint8_t type;
	struct buffer buf;
	struct stat stbuf;
	struct iovec iov[1];
	int err = -1;
	const char *remote_dir = base_path[0] ? base_path : ".";

	buf_init(&buf, 0);
	buf_add_string(&buf, remote_dir);
	buf_to_iov(&buf, &iov[0]);
	if (sftp_send_iov(conn, SSH_FXP_LSTAT, id, iov, 1) == -1)
		goto out;
	buf_clear(&buf);
	if (sftp_read(conn, &type, &buf) == -1)
		goto out;
	if (type != SSH_FXP_ATTRS && type != SSH_FXP_STATUS) {
		fprintf(stderr, "protocol error\n");
		goto out;
	}
	if (buf_get_uint32(&buf, &replid) == -1)
		goto out;
	if (replid != id) {
		fprintf(stderr, "bad reply ID\n");
		goto out;
	}
	if (type == SSH_FXP_STATUS) {
		uint32_t serr;
		if (buf_get_uint32(&buf, &serr) == -1)
			goto out;

		fprintf(stderr, "%s:%s: %s\n", sshfs.host, remote_dir,
			strerror(sftp_error_to_errno(serr)));

		goto out;
	}

	int err2 = buf_get_attrs(&buf, &stbuf, &flags);
	if (err2) {
		err = err2;
		goto out;
	}

	if (!(flags & SSH_FILEXFER_ATTR_PERMISSIONS))
		goto out;

	if (!S_ISDIR(stbuf.st_mode)) {
		fprintf(stderr, "%s:%s: Not a directory\n", sshfs.host,
			remote_dir);
		goto out;
	}

	err = 0;

out:
	buf_free(&buf);
	return err;
}

static int connect_remote(struct conn *conn)
{
	int err;

	if (sshfs.passive)
		err = connect_passive(conn);
	else if (sshfs.directport)
		err = connect_to(conn, sshfs.host, sshfs.directport);
	else if (sshfs.vsock)
		err = connect_vsock(conn, sshfs.vsock);
	else
		err = start_ssh(conn);
	if (!err)
		err = sftp_init(conn);

	if (err)
		close_conn(conn);
	else
		sshfs.num_connect++;

	return err;
}

static int start_processing_thread(struct conn *conn)
{
	int err;
	pthread_t thread_id;
	sigset_t oldset;
	sigset_t newset;

	if (conn->processing_thread_started)
		return 0;

	if (conn->rfd == -1) {
		err = connect_remote(conn);
		if (err)
			return -EIO;
	}

	if (sshfs.detect_uid) {
		sftp_detect_uid(conn);
		sshfs.detect_uid = 0;
	}

	sigemptyset(&newset);
	sigaddset(&newset, SIGTERM);
	sigaddset(&newset, SIGINT);
	sigaddset(&newset, SIGHUP);
	sigaddset(&newset, SIGQUIT);
	pthread_sigmask(SIG_BLOCK, &newset, &oldset);
	err = pthread_create(&thread_id, NULL, process_requests, conn);
	if (err) {
		fprintf(stderr, "failed to create thread: %s\n", strerror(err));
		return -EIO;
	}
	pthread_detach(thread_id);
	pthread_sigmask(SIG_SETMASK, &oldset, NULL);
	conn->processing_thread_started = 1;
	return 0;
}

static void *sshfs_init(struct fuse_conn_info *conn,
                        struct fuse_config *cfg)
{
	/* Readahead should be done by kernel or sshfs but not both */
	if (conn->capable & FUSE_CAP_ASYNC_READ)
		sshfs.sync_read = 1;

	// These workarounds require the "path" argument.
	cfg->nullpath_ok = !(sshfs.truncate_workaround || sshfs.fstat_workaround);

	// When using multiple connections, release() needs to know the path
	if (sshfs.max_conns > 1)
		cfg->nullpath_ok = 0;

	// Lookup of . and .. is supported
	conn->capable |= FUSE_CAP_EXPORT_SUPPORT;

	if (!sshfs.delay_connect)
		start_processing_thread(&sshfs.conns[0]);

	// SFTP only supports 1-second time resolution
	conn->time_gran = 1000000000;

	return NULL;
}

static int sftp_request_wait(struct request *req, uint8_t type,
                             uint8_t expect_type, struct buffer *outbuf)
{
	int err;

	if (req->error) {
		err = req->error;
		goto out;
	}
	while (sem_wait(&req->ready));
	if (req->error) {
		err = req->error;
		goto out;
	}
	err = -EIO;
	if (req->reply_type != expect_type &&
	    req->reply_type != SSH_FXP_STATUS) {
		fprintf(stderr, "protocol error\n");
		goto out;
	}
	if (req->reply_type == SSH_FXP_STATUS) {
		uint32_t serr;
		if (buf_get_uint32(&req->reply, &serr) == -1)
			goto out;

		switch (serr) {
		case SSH_FX_OK:
			if (expect_type == SSH_FXP_STATUS)
				err = 0;
			else
				err = -EIO;
			break;

		case SSH_FX_EOF:
			if (type == SSH_FXP_READ || type == SSH_FXP_READDIR)
				err = MY_EOF;
			else
				err = -EIO;
			break;

		case SSH_FX_FAILURE:
			if (type == SSH_FXP_RMDIR)
				err = -ENOTEMPTY;
			else
				err = -EPERM;
			break;

		default:
			err = -sftp_error_to_errno(serr);
		}
	} else {
		buf_init(outbuf, req->reply.size - req->reply.len);
		buf_get_mem(&req->reply, outbuf->p, outbuf->size);
		err = 0;
	}

out:
	pthread_mutex_lock(&sshfs.lock);
	request_free(req);
	pthread_mutex_unlock(&sshfs.lock);
	return err;
}

static int sftp_request_send(struct conn *conn, uint8_t type, struct iovec *iov,
			     size_t count, request_func begin_func, request_func end_func,
			     int want_reply, void *data, struct request **reqp)
{
	int err;
	uint32_t id;
	struct request *req = g_new0(struct request, 1);

	req->want_reply = want_reply;
	req->end_func = end_func;
	req->data = data;
	sem_init(&req->ready, 0, 0);
	buf_init(&req->reply, 0);
	pthread_mutex_lock(&sshfs.lock);
	if (begin_func)
		begin_func(req);
	id = sftp_get_id();
	req->id = id;
	req->conn = conn;
	req->conn->req_count++;
	err = start_processing_thread(conn);
	if (err) {
		pthread_mutex_unlock(&sshfs.lock);
		goto out;
	}
	req->len = iov_length(iov, count) + 9;
	sshfs.outstanding_len += req->len;
	while (sshfs.outstanding_len > sshfs.max_outstanding_len)
		pthread_cond_wait(&sshfs.outstanding_cond, &sshfs.lock);

	g_hash_table_insert(sshfs.reqtab, GUINT_TO_POINTER(id), req);
	if (sshfs.debug) {
		gettimeofday(&req->start, NULL);
		sshfs.num_sent++;
		sshfs.bytes_sent += req->len;
	}
	DEBUG("[%05i] %s\n", id, type_name(type));
	pthread_mutex_unlock(&sshfs.lock);

	err = -EIO;
	if (sftp_send_iov(conn, type, id, iov, count) == -1) {
		gboolean rmed;

		pthread_mutex_lock(&sshfs.lock);
		rmed = g_hash_table_remove(sshfs.reqtab, GUINT_TO_POINTER(id));
		pthread_mutex_unlock(&sshfs.lock);

		if (!rmed && !want_reply) {
			/* request already freed */
			return err;
		}
		goto out;
	}
	if (want_reply)
		*reqp = req;
	return 0;

out:
	req->error = err;
	if (!want_reply)
		sftp_request_wait(req, type, 0, NULL);
	else
		*reqp = req;

	return err;
}

static int sftp_request_iov(struct conn *conn, uint8_t type, struct iovec *iov,
			    size_t count, uint8_t expect_type, struct buffer *outbuf)
{
	int err;
	struct request *req;

	err = sftp_request_send(conn, type, iov, count, NULL, NULL,
				expect_type, NULL, &req);
	if (expect_type == 0)
		return err;

	return sftp_request_wait(req, type, expect_type, outbuf);
}

static int sftp_request(struct conn *conn, uint8_t type, const struct buffer *buf,
			uint8_t expect_type, struct buffer *outbuf)
{
	struct iovec iov;

	buf_to_iov(buf, &iov);
	return sftp_request_iov(conn, type, &iov, 1, expect_type, outbuf);
}

static int sshfs_access(const char *path, int mask)
{
	struct stat stbuf;
	int err = 0;

	if (mask & X_OK) {
		err = sshfs.op->getattr(path, &stbuf, NULL);
		if (!err) {
			if (S_ISREG(stbuf.st_mode) &&
			    !(stbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)))
				err = -EACCES;
		}
	}
	return err;
}

static int count_components(const char *p)
{
	int ctr;

	for (; *p == '/'; p++);
	for (ctr = 0; *p; ctr++) {
		for (; *p && *p != '/'; p++);
		for (; *p == '/'; p++);
	}
	return ctr;
}

static void strip_common(const char **sp, const char **tp)
{
	const char *s = *sp;
	const char *t = *tp;
	do {
		for (; *s == '/'; s++);
		for (; *t == '/'; t++);
		*tp = t;
		*sp = s;
		for (; *s == *t && *s && *s != '/'; s++, t++);
	} while ((*s == *t && *s) || (!*s && *t == '/') || (*s == '/' && !*t));
}

static void transform_symlink(const char *path, char **linkp)
{
	const char *l = *linkp;
	const char *b = sshfs.base_path;
	char *newlink;
	char *s;
	int dotdots;
	int i;

	if (l[0] != '/' || b[0] != '/')
		return;

	strip_common(&l, &b);
	if (*b)
		return;

	strip_common(&l, &path);
	dotdots = count_components(path);
	if (!dotdots)
		return;
	dotdots--;

	newlink = malloc(dotdots * 3 + strlen(l) + 2);
	if (!newlink) {
		fprintf(stderr, "sshfs: memory allocation failed\n");
		abort();
	}
	for (s = newlink, i = 0; i < dotdots; i++, s += 3)
		strcpy(s, "../");

	if (l[0])
		strcpy(s, l);
	else if (!dotdots)
		strcpy(s, ".");
	else
		s[0] = '\0';

	free(*linkp);
	*linkp = newlink;
}

static int sshfs_readlink(const char *path, char *linkbuf, size_t size)
{
	int err;
	struct buffer buf;
	struct buffer name;

	assert(size > 0);

	if (sshfs.server_version < 3)
		return -EPERM;

	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_READLINK, &buf, SSH_FXP_NAME, &name);
	if (!err) {
		uint32_t count;
		char *link;
		err = -EIO;
		if(buf_get_uint32(&name, &count) != -1 && count == 1 &&
		   buf_get_string(&name, &link) != -1) {
			if (sshfs.transform_symlinks)
				transform_symlink(path, &link);
			strncpy(linkbuf, link, size - 1);
			linkbuf[size - 1] = '\0';
			free(link);
			err = 0;
		}
		buf_free(&name);
	}
	buf_free(&buf);
	return err;
}

static int sftp_readdir_send(struct conn *conn, struct request **req,
			     struct buffer *handle)
{
	struct iovec iov;

	buf_to_iov(handle, &iov);
	return sftp_request_send(conn, SSH_FXP_READDIR, &iov, 1, NULL, NULL,
				 SSH_FXP_NAME, NULL, req);
}

static int sshfs_req_pending(struct request *req)
{
	if (g_hash_table_lookup(sshfs.reqtab, GUINT_TO_POINTER(req->id)))
		return 1;
	else
		return 0;
}

static int sftp_readdir_async(struct conn *conn, struct buffer *handle,
			      void *buf, off_t offset, fuse_fill_dir_t filler)
{
	int err = 0;
	int outstanding = 0;
	int max = READDIR_START;
	GList *list = NULL;

	int done = 0;

	assert(offset == 0);
	while (!done || outstanding) {
		struct request *req;
		struct buffer name;
		int tmperr;

		while (!done && outstanding < max) {
			tmperr = sftp_readdir_send(conn, &req, handle);

			if (tmperr && !done) {
				err = tmperr;
				done = 1;
				break;
			}

			list = g_list_append(list, req);
			outstanding++;
		}

		if (outstanding) {
			GList *first;
			/* wait for response to next request */
			first = g_list_first(list);
			req = first->data;
			list = g_list_delete_link(list, first);
			outstanding--;

			if (done) {
				/* We need to cache want_reply, since processing
				   thread may free req right after unlock() if
				   want_reply == 0 */
				int want_reply;
				pthread_mutex_lock(&sshfs.lock);
				if (sshfs_req_pending(req))
					req->want_reply = 0;
				want_reply = req->want_reply;
				pthread_mutex_unlock(&sshfs.lock);
				if (!want_reply)
					continue;
			}

			tmperr = sftp_request_wait(req, SSH_FXP_READDIR,
						    SSH_FXP_NAME, &name);

			if (tmperr && !done) {
				err = tmperr;
				if (err == MY_EOF)
					err = 0;
				done = 1;
			}
			if (!done) {
				err = buf_get_entries(&name, buf, filler);
				buf_free(&name);

				/* increase number of outstanding requests */
				if (max < READDIR_MAX)
					max++;

				if (err)
					done = 1;
			}
		}
	}
	assert(list == NULL);

	return err;
}

static int sftp_readdir_sync(struct conn *conn, struct buffer *handle,
			     void *buf, off_t offset, fuse_fill_dir_t filler)
{
	int err;
	assert(offset == 0);
	do {
		struct buffer name;
		err = sftp_request(conn, SSH_FXP_READDIR, handle, SSH_FXP_NAME, &name);
		if (!err) {
			err = buf_get_entries(&name, buf, filler);
			buf_free(&name);
		}
	} while (!err);
	if (err == MY_EOF)
		err = 0;

	return err;
}

static int sshfs_opendir(const char *path, struct fuse_file_info *fi)
{
	int err;
	struct conn *conn;
	struct buffer buf;
	struct dir_handle *handle;

	handle = g_new0(struct dir_handle, 1);
	if(handle == NULL)
		return -ENOMEM;

	// Commutes with pending write(), so we can use any connection
	conn = get_conn(NULL, NULL);
	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	err = sftp_request(conn, SSH_FXP_OPENDIR, &buf, SSH_FXP_HANDLE, &handle->buf);
	if (!err) {
		buf_finish(&handle->buf);
		pthread_mutex_lock(&sshfs.lock);
		handle->conn = conn;
		handle->conn->dir_count++;
		pthread_mutex_unlock(&sshfs.lock);
		fi->fh = (unsigned long) handle;
	} else
		g_free(handle);
	buf_free(&buf);
	return err;
}

static int sshfs_readdir(const char *path, void *dbuf, fuse_fill_dir_t filler,
			 off_t offset, struct fuse_file_info *fi,
			 enum fuse_readdir_flags flags)
{
	(void) path; (void) flags;
	int err;
	struct dir_handle *handle;

	handle = (struct dir_handle*) fi->fh;

	if (sshfs.sync_readdir)
		err = sftp_readdir_sync(handle->conn, &handle->buf, dbuf,
					offset, filler);
	else
		err = sftp_readdir_async(handle->conn, &handle->buf, dbuf,
					 offset, filler);

	return err;
}

static int sshfs_releasedir(const char *path, struct fuse_file_info *fi)
{
	(void) path;
	int err;
	struct dir_handle *handle;

	handle = (struct dir_handle*) fi->fh;
	err = sftp_request(handle->conn, SSH_FXP_CLOSE, &handle->buf, 0, NULL);
	pthread_mutex_lock(&sshfs.lock);
	handle->conn->dir_count--;
	pthread_mutex_unlock(&sshfs.lock);
	buf_free(&handle->buf);
	g_free(handle);
	return err;
}


static int sshfs_mkdir(const char *path, mode_t mode)
{
	int err;
	struct buffer buf;
	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
	buf_add_uint32(&buf, mode);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_MKDIR, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);

	if (err == -EPERM) {
		if (sshfs.op->access(path, R_OK) == 0) {
			return -EEXIST;
		}
	}

	return err;
}

static int sshfs_mknod(const char *path, mode_t mode, dev_t rdev)
{
	int err;
	struct conn *conn;
	struct buffer buf;
	struct buffer handle;
	(void) rdev;

	if ((mode & S_IFMT) != S_IFREG)
		return -EPERM;

	// Commutes with pending write(), so we can use any connection
	conn = get_conn(NULL, NULL);

	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	buf_add_uint32(&buf, SSH_FXF_WRITE | SSH_FXF_CREAT | SSH_FXF_EXCL);
	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
	buf_add_uint32(&buf, mode);
	err = sftp_request(conn, SSH_FXP_OPEN, &buf, SSH_FXP_HANDLE, &handle);
	if (!err) {
		int err2;
		buf_finish(&handle);
		err2 = sftp_request(conn, SSH_FXP_CLOSE, &handle, SSH_FXP_STATUS, NULL);
		if (!err)
			err = err2;
		buf_free(&handle);
	}
	buf_free(&buf);
	return err;
}

static int sshfs_symlink(const char *from, const char *to)
{
	int err;
	struct buffer buf;

	if (sshfs.server_version < 3)
		return -EPERM;

	/* openssh sftp server doesn't follow standard: link target and
	   link name are mixed up, so we must also be non-standard :( */
	buf_init(&buf, 0);
	buf_add_string(&buf, from);
	buf_add_path(&buf, to);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_SYMLINK, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_unlink(const char *path)
{
	int err;
	struct buffer buf;
	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_REMOVE, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_rmdir(const char *path)
{
	int err;
	struct buffer buf;
	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_RMDIR, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_do_rename(const char *from, const char *to)
{
	int err;
	struct buffer buf;
	buf_init(&buf, 0);
	buf_add_path(&buf, from);
	buf_add_path(&buf, to);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_RENAME, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_ext_posix_rename(const char *from, const char *to)
{
	int err;
	struct buffer buf;
	buf_init(&buf, 0);
	buf_add_string(&buf, SFTP_EXT_POSIX_RENAME);
	buf_add_path(&buf, from);
	buf_add_path(&buf, to);
	// Commutes with pending write(), so we can use any connection
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_EXTENDED, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static void random_string(char *str, int length)
{
	int i;
	for (i = 0; i < length; i++)
		*str++ = (char)('0' + rand_r(&sshfs.randseed) % 10);
	*str = '\0';
}

static int sshfs_rename(const char *from, const char *to, unsigned int flags)
{
	int err;
	struct conntab_entry *ce;

	if(flags != 0)
		return -EINVAL;

	if (sshfs.ext_posix_rename)
		err = sshfs_ext_posix_rename(from, to);
	else
		err = sshfs_do_rename(from, to);
	if (err == -EPERM && sshfs.rename_workaround) {
		size_t tolen = strlen(to);
		if (tolen + RENAME_TEMP_CHARS < PATH_MAX) {
			int tmperr;
			char totmp[PATH_MAX];
			strcpy(totmp, to);
			random_string(totmp + tolen, RENAME_TEMP_CHARS);
			tmperr = sshfs_do_rename(to, totmp);
			if (!tmperr) {
				err = sshfs_do_rename(from, to);
				if (!err)
					err = sshfs_unlink(totmp);
				else
					sshfs_do_rename(totmp, to);
			}
		}
	}
	if (err == -EPERM && sshfs.renamexdev_workaround)
		err = -EXDEV;

	if (!err && sshfs.max_conns > 1) {
		pthread_mutex_lock(&sshfs.lock);
		ce = g_hash_table_lookup(sshfs.conntab, from);
		if (ce != NULL) {
			g_hash_table_replace(sshfs.conntab, g_strdup(to), ce);
			g_hash_table_remove(sshfs.conntab, from);
		}
		pthread_mutex_unlock(&sshfs.lock);
	}

	return err;
}

static int sshfs_link(const char *from, const char *to)
{
	int err = -ENOSYS;

	if (sshfs.ext_hardlink && !sshfs.disable_hardlink) {
		struct buffer buf;

		buf_init(&buf, 0);
		buf_add_string(&buf, SFTP_EXT_HARDLINK);
		buf_add_path(&buf, from);
		buf_add_path(&buf, to);
		// Commutes with pending write(), so we can use any connection
		err = sftp_request(get_conn(NULL, NULL), SSH_FXP_EXTENDED, &buf, SSH_FXP_STATUS,
				   NULL);
		buf_free(&buf);
	}

	return err;
}

static inline int sshfs_file_is_conn(struct sshfs_file *sf)
{
	int ret;

	pthread_mutex_lock(&sshfs.lock);
	ret = (sf->connver == sf->conn->connver);
	pthread_mutex_unlock(&sshfs.lock);

	return ret;
}

static inline struct sshfs_file *get_sshfs_file(struct fuse_file_info *fi)
{
	return (struct sshfs_file *) (uintptr_t) fi->fh;
}

static int sshfs_chmod(const char *path, mode_t mode,
                       struct fuse_file_info *fi)
{
	(void) fi;
	int err;
	struct buffer buf;
	struct sshfs_file *sf = NULL;

	if (fi != NULL) {
		sf = get_sshfs_file(fi);
		if (!sshfs_file_is_conn(sf))
			return -EIO;
	}

	buf_init(&buf, 0);
	if (sf == NULL)
		buf_add_path(&buf, path);
	else
		buf_add_buf(&buf, &sf->handle);

	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
	buf_add_uint32(&buf, mode);

	/* FIXME: really needs LSETSTAT extension (debian Bug#640038) */
	// Commutes with pending write(), so we can use any connection
	// if the file is not open.
	err = sftp_request(get_conn(sf, NULL),
			   sf == NULL ? SSH_FXP_SETSTAT : SSH_FXP_FSETSTAT,
			   &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_chown(const char *path, uid_t uid, gid_t gid,
                       struct fuse_file_info *fi)
{
	(void) fi;
	int err;
	struct buffer buf;
	struct sshfs_file *sf = NULL;

	if (fi != NULL) {
		sf = get_sshfs_file(fi);
		if (!sshfs_file_is_conn(sf))
			return -EIO;
	}

	if (sshfs.remote_uid_detected) {
		if (uid == sshfs.local_uid)
			uid = sshfs.remote_uid;
		if (gid == sshfs.local_gid)
			gid = sshfs.remote_gid;
	}
	if (sshfs.idmap == IDMAP_FILE && sshfs.r_uid_map)
		if(translate_id(&uid, sshfs.r_uid_map) == -1)
			return -EPERM;
	if (sshfs.idmap == IDMAP_FILE && sshfs.r_gid_map)
		if (translate_id(&gid, sshfs.r_gid_map) == -1)
			return -EPERM;

	buf_init(&buf, 0);
	if (sf == NULL)
		buf_add_path(&buf, path);
	else
		buf_add_buf(&buf, &sf->handle);
	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_UIDGID);
	buf_add_uint32(&buf, uid);
	buf_add_uint32(&buf, gid);

	// Commutes with pending write(), so we can use any connection
	// if the file is not open.
	err = sftp_request(get_conn(sf, NULL),
			   sf == NULL ? SSH_FXP_SETSTAT : SSH_FXP_FSETSTAT,
			   &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_truncate_workaround(const char *path, off_t size,
                                     struct fuse_file_info *fi);

static void sshfs_inc_modifver(void)
{
	pthread_mutex_lock(&sshfs.lock);
	sshfs.modifver++;
	pthread_mutex_unlock(&sshfs.lock);
}

static int sshfs_utimens(const char *path, const struct timespec tv[2],
			 struct fuse_file_info *fi)
{
	(void) fi;
	int err;
	struct buffer buf;
	struct sshfs_file *sf = NULL;
	time_t asec = tv[0].tv_sec, msec = tv[1].tv_sec;

	struct timeval now;
	gettimeofday(&now, NULL);
	if (asec == 0)
		asec = now.tv_sec;
	if (msec == 0)
		msec = now.tv_sec;

	if (fi != NULL) {
		sf = get_sshfs_file(fi);
		if (!sshfs_file_is_conn(sf))
			return -EIO;
	}

	buf_init(&buf, 0);
	if (sf == NULL)
		buf_add_path(&buf, path);
	else
		buf_add_buf(&buf, &sf->handle);
	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_ACMODTIME);
	buf_add_uint32(&buf, asec);
	buf_add_uint32(&buf, msec);

	err = sftp_request(get_conn(sf, path),
			   sf == NULL ? SSH_FXP_SETSTAT : SSH_FXP_FSETSTAT,
			   &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_open_common(const char *path, mode_t mode,
                             struct fuse_file_info *fi)
{
	int err;
	int err2;
	struct buffer buf;
	struct buffer outbuf;
	struct stat stbuf;
	struct sshfs_file *sf;
	struct request *open_req;
	struct conntab_entry *ce;
	uint32_t pflags = 0;
	struct iovec iov;
	uint8_t type;
	uint64_t wrctr = 0;

	if (sshfs.dir_cache)
		wrctr = cache_get_write_ctr();

	if (sshfs.direct_io)
		fi->direct_io = 1;

	if ((fi->flags & O_ACCMODE) == O_RDONLY)
		pflags = SSH_FXF_READ;
	else if((fi->flags & O_ACCMODE) == O_WRONLY)
		pflags = SSH_FXF_WRITE;
	else if ((fi->flags & O_ACCMODE) == O_RDWR)
		pflags = SSH_FXF_READ | SSH_FXF_WRITE;
	else
		return -EINVAL;

	if (fi->flags & O_CREAT)
		pflags |= SSH_FXF_CREAT;

	if (fi->flags & O_EXCL)
		pflags |= SSH_FXF_EXCL;

	if (fi->flags & O_TRUNC)
		pflags |= SSH_FXF_TRUNC;

	if (fi->flags & O_APPEND)
		pflags |= SSH_FXF_APPEND;

	sf = g_new0(struct sshfs_file, 1);
	list_init(&sf->write_reqs);
	pthread_cond_init(&sf->write_finished, NULL);
	/* Assume random read after open */
	sf->is_seq = 0;
	sf->next_pos = 0;
	pthread_mutex_lock(&sshfs.lock);
	sf->modifver= sshfs.modifver;
	if (sshfs.max_conns > 1) {
		ce = g_hash_table_lookup(sshfs.conntab, path);
		if (!ce) {
			ce = g_malloc(sizeof(struct conntab_entry));
			ce->refcount = 0;
			ce->conn = get_conn(NULL, NULL);
			g_hash_table_insert(sshfs.conntab, g_strdup(path), ce);
		}
		sf->conn = ce->conn;
		ce->refcount++;
		sf->conn->file_count++;
		assert(sf->conn->file_count > 0);
	} else {
		sf->conn = &sshfs.conns[0];
		ce = NULL; // only to silence compiler warning
	}
	sf->connver = sf->conn->connver;
	pthread_mutex_unlock(&sshfs.lock);
	buf_init(&buf, 0);
	buf_add_path(&buf, path);
	buf_add_uint32(&buf, pflags);
	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_PERMISSIONS);
	buf_add_uint32(&buf, mode);
	buf_to_iov(&buf, &iov);
	sftp_request_send(sf->conn, SSH_FXP_OPEN, &iov, 1, NULL, NULL, 1, NULL,
			  &open_req);
	buf_clear(&buf);
	buf_add_path(&buf, path);
	type = sshfs.follow_symlinks ? SSH_FXP_STAT : SSH_FXP_LSTAT;
	err2 = sftp_request(sf->conn, type, &buf, SSH_FXP_ATTRS, &outbuf);
	if (!err2) {
		err2 = buf_get_attrs(&outbuf, &stbuf, NULL);
		buf_free(&outbuf);
	}
	err = sftp_request_wait(open_req, SSH_FXP_OPEN, SSH_FXP_HANDLE,
				&sf->handle);
	if (!err && err2) {
		buf_finish(&sf->handle);
		sftp_request(sf->conn, SSH_FXP_CLOSE, &sf->handle, 0, NULL);
		buf_free(&sf->handle);
		err = err2;
	}

	if (!err) {
		if (sshfs.dir_cache)
			cache_add_attr(path, &stbuf, wrctr);
		buf_finish(&sf->handle);
		fi->fh = (unsigned long) sf;
	} else {
		if (sshfs.dir_cache)
			cache_invalidate(path);
		if (sshfs.max_conns > 1) {
			pthread_mutex_lock(&sshfs.lock);
			sf->conn->file_count--;
			ce->refcount--;
			if(ce->refcount == 0) {
				g_hash_table_remove(sshfs.conntab, path);
				g_free(ce);
			}
			pthread_mutex_unlock(&sshfs.lock);
		}
		g_free(sf);
	}
	buf_free(&buf);
	return err;
}

static int sshfs_open(const char *path, struct fuse_file_info *fi)
{
	return sshfs_open_common(path, 0, fi);
}

static int sshfs_flush(const char *path, struct fuse_file_info *fi)
{
	int err;
	struct sshfs_file *sf = get_sshfs_file(fi);
	struct list_head write_reqs;
	struct list_head *curr_list;

	if (!sshfs_file_is_conn(sf))
		return -EIO;

	if (sshfs.sync_write)
		return 0;

	(void) path;
	pthread_mutex_lock(&sshfs.lock);
	if (!list_empty(&sf->write_reqs)) {
		curr_list = sf->write_reqs.prev;
		list_del(&sf->write_reqs);
		list_init(&sf->write_reqs);
		list_add(&write_reqs, curr_list);
		while (!list_empty(&write_reqs))
			pthread_cond_wait(&sf->write_finished, &sshfs.lock);
	}
	err = sf->write_error;
	sf->write_error = 0;
	pthread_mutex_unlock(&sshfs.lock);
	return err;
}

static int sshfs_fsync(const char *path, int isdatasync,
                       struct fuse_file_info *fi)
{
	int err;
	(void) isdatasync;

	err = sshfs_flush(path, fi);
	if (err)
		return err;

	if (!sshfs.ext_fsync)
		return err;

	struct buffer buf;
	struct sshfs_file *sf = get_sshfs_file(fi);
	buf_init(&buf, 0);
	buf_add_string(&buf, SFTP_EXT_FSYNC);
	buf_add_buf(&buf, &sf->handle);
	err = sftp_request(sf->conn, SSH_FXP_EXTENDED, &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);
	return err;
}

static int sshfs_release(const char *path, struct fuse_file_info *fi)
{
	struct sshfs_file *sf = get_sshfs_file(fi);
	struct buffer *handle = &sf->handle;
	struct conntab_entry *ce;
	if (sshfs_file_is_conn(sf)) {
		sshfs_flush(path, fi);
		sftp_request(sf->conn, SSH_FXP_CLOSE, handle, 0, NULL);
	}
	buf_free(handle);
	chunk_put_locked(sf->readahead);
	if (sshfs.max_conns > 1) {
		pthread_mutex_lock(&sshfs.lock);
		sf->conn->file_count--;
		ce = g_hash_table_lookup(sshfs.conntab, path);
		ce->refcount--;
		if(ce->refcount == 0) {
			g_hash_table_remove(sshfs.conntab, path);
			g_free(ce);
		}
		pthread_mutex_unlock(&sshfs.lock);
	}
	g_free(sf);
	return 0;
}

static void sshfs_read_end(struct request *req)
{
	struct read_req *rreq = (struct read_req *) req->data;
	if (req->error)
		rreq->res = req->error;
	else if (req->replied) {
		rreq->res = -EIO;

		if (req->reply_type == SSH_FXP_STATUS) {
			uint32_t serr;
			if (buf_get_uint32(&req->reply, &serr) != -1) {
				if (serr == SSH_FX_EOF)
					rreq->res = 0;
				else
					rreq->res = -sftp_error_to_errno(serr);
			}
		} else if (req->reply_type == SSH_FXP_DATA) {
			uint32_t retsize;
			if (buf_get_uint32(&req->reply, &retsize) != -1) {
				if (retsize > rreq->size) {
					fprintf(stderr, "long read\n");
				} else if (buf_check_get(&req->reply, retsize) != -1) {
					rreq->res = retsize;
					rreq->data = req->reply;
					buf_init(&req->reply, 0);
				}
			}
		} else {
			fprintf(stderr, "protocol error\n");
		}
	} else {
		rreq->res = -EIO;
	}

	rreq->sio->num_reqs--;
	if (!rreq->sio->num_reqs)
		pthread_cond_broadcast(&rreq->sio->finished);
}

static void sshfs_read_begin(struct request *req)
{
	struct read_req *rreq = (struct read_req *) req->data;
	rreq->sio->num_reqs++;
}

static struct read_chunk *sshfs_send_read(struct sshfs_file *sf, size_t size,
					  off_t offset)
{
	struct read_chunk *chunk = g_new0(struct read_chunk, 1);
	struct buffer *handle = &sf->handle;

	pthread_cond_init(&chunk->sio.finished, NULL);
	list_init(&chunk->reqs);
	chunk->size = size;
	chunk->offset = offset;
	chunk->refs = 1;

	while (size) {
		int err;
		struct buffer buf;
		struct iovec iov[1];
		struct read_req *rreq;
		size_t bsize = size < sshfs.max_read ? size : sshfs.max_read;

		rreq = g_new0(struct read_req, 1);
		rreq->sio = &chunk->sio;
		rreq->size = bsize;
		buf_init(&rreq->data, 0);
		list_add(&rreq->list, &chunk->reqs);

		buf_init(&buf, 0);
		buf_add_buf(&buf, handle);
		buf_add_uint64(&buf, offset);
		buf_add_uint32(&buf, bsize);
		buf_to_iov(&buf, &iov[0]);
		err = sftp_request_send(sf->conn, SSH_FXP_READ, iov, 1,
					sshfs_read_begin,
					sshfs_read_end,
					0, rreq, NULL);

		buf_free(&buf);
		if (err)
			break;

		size -= bsize;
		offset += bsize;
	}

	return chunk;
}

static int wait_chunk(struct read_chunk *chunk, char *buf, size_t size)
{
	int res = 0;
	struct read_req *rreq;

	pthread_mutex_lock(&sshfs.lock);
	while (chunk->sio.num_reqs)
	       pthread_cond_wait(&chunk->sio.finished, &sshfs.lock);
	pthread_mutex_unlock(&sshfs.lock);


	if (chunk->sio.error) {
		if (chunk->sio.error != MY_EOF)
			res = chunk->sio.error;

		goto out;
	}

	while (!list_empty(&chunk->reqs) && size) {
		rreq = list_entry(chunk->reqs.prev, struct read_req, list);

		if (rreq->res < 0) {
			chunk->sio.error = rreq->res;
			break;
		} if (rreq->res == 0) {
			chunk->sio.error = MY_EOF;
			break;
		} else if (size < (size_t) rreq->res) {
			buf_get_mem(&rreq->data, buf, size);
			rreq->res -= size;
			rreq->size -= size;
			res += size;
			break;
		} else {
			buf_get_mem(&rreq->data, buf, rreq->res);
			res += rreq->res;
			if ((size_t) rreq->res < rreq->size) {
				chunk->sio.error = MY_EOF;
				break;
			}
			buf += rreq->res;
			size -= rreq->res;
			list_del(&rreq->list);
			buf_free(&rreq->data);
			g_free(rreq);
		}
	}

	if (res > 0) {
		chunk->offset += res;
		chunk->size -= res;
	}

out:
	chunk_put_locked(chunk);
	return res;
}

static int sshfs_sync_read(struct sshfs_file *sf, char *buf, size_t size,
                           off_t offset)
{
	struct read_chunk *chunk;

	chunk = sshfs_send_read(sf, size, offset);
	return wait_chunk(chunk, buf, size);
}

static void submit_read(struct sshfs_file *sf, size_t size, off_t offset,
                        struct read_chunk **chunkp)
{
	struct read_chunk *chunk;

	chunk = sshfs_send_read(sf, size, offset);
	pthread_mutex_lock(&sshfs.lock);
	chunk->modifver = sshfs.modifver;
	chunk_put(*chunkp);
	*chunkp = chunk;
	chunk->refs++;
	pthread_mutex_unlock(&sshfs.lock);
}

static struct read_chunk *search_read_chunk(struct sshfs_file *sf, off_t offset)
{
	struct read_chunk *ch = sf->readahead;
	if (ch && ch->offset == offset && ch->modifver == sshfs.modifver) {
		ch->refs++;
		return ch;
	} else
		return NULL;
}

static int sshfs_async_read(struct sshfs_file *sf, char *rbuf, size_t size,
                            off_t offset)
{
	int res = 0;
	size_t total = 0;
	struct read_chunk *chunk;
	struct read_chunk *chunk_prev = NULL;
	size_t origsize = size;
	int curr_is_seq;

	pthread_mutex_lock(&sshfs.lock);
	curr_is_seq = sf->is_seq;
	sf->is_seq = (sf->next_pos == offset && sf->modifver == sshfs.modifver);
	sf->next_pos = offset + size;
	sf->modifver = sshfs.modifver;
	chunk = search_read_chunk(sf, offset);
	pthread_mutex_unlock(&sshfs.lock);

	if (chunk && chunk->size < size) {
		chunk_prev = chunk;
		size -= chunk->size;
		offset += chunk->size;
		chunk = NULL;
	}

	if (!chunk)
		submit_read(sf, size, offset, &chunk);

	if (curr_is_seq && chunk && chunk->size <= size)
		submit_read(sf, origsize, offset + size, &sf->readahead);

	if (chunk_prev) {
		size_t prev_size = chunk_prev->size;
		res = wait_chunk(chunk_prev, rbuf, prev_size);
		if (res < (int) prev_size) {
			chunk_put_locked(chunk);
			return res;
		}
		rbuf += res;
		total += res;
	}
	res = wait_chunk(chunk, rbuf, size);
	if (res > 0)
		total += res;
	if (res < 0)
		return res;

	return total;
}

static int sshfs_read(const char *path, char *rbuf, size_t size, off_t offset,
                      struct fuse_file_info *fi)
{
	struct sshfs_file *sf = get_sshfs_file(fi);
	(void) path;

	if (!sshfs_file_is_conn(sf))
		return -EIO;

	if (sshfs.sync_read)
		return sshfs_sync_read(sf, rbuf, size, offset);
	else
		return sshfs_async_read(sf, rbuf, size, offset);
}

static void sshfs_write_begin(struct request *req)
{
	struct sshfs_file *sf = (struct sshfs_file *) req->data;
	list_add(&req->list, &sf->write_reqs);
}

static void sshfs_write_end(struct request *req)
{
	uint32_t serr;
	struct sshfs_file *sf = (struct sshfs_file *) req->data;

	if (req->error)
		sf->write_error = req->error;
	else if (req->replied) {
		if (req->reply_type != SSH_FXP_STATUS) {
			fprintf(stderr, "protocol error\n");
		} else if (buf_get_uint32(&req->reply, &serr) != -1 &&
			serr != SSH_FX_OK) {
			sf->write_error = -EIO;
		}
	}
	list_del(&req->list);
	pthread_cond_broadcast(&sf->write_finished);
}

static int sshfs_async_write(struct sshfs_file *sf, const char *wbuf,
			     size_t size, off_t offset)
{
	int err = 0;
	struct buffer *handle = &sf->handle;

	while (!err && size) {
		struct buffer buf;
		struct iovec iov[2];
		size_t bsize = size < sshfs.max_write ? size : sshfs.max_write;

		buf_init(&buf, 0);
		buf_add_buf(&buf, handle);
		buf_add_uint64(&buf, offset);
		buf_add_uint32(&buf, bsize);
		buf_to_iov(&buf, &iov[0]);
		iov[1].iov_base = (void *) wbuf;
		iov[1].iov_len = bsize;
		err = sftp_request_send(sf->conn, SSH_FXP_WRITE, iov, 2,
					sshfs_write_begin, sshfs_write_end,
					0, sf, NULL);
		buf_free(&buf);
		size -= bsize;
		wbuf += bsize;
		offset += bsize;
	}

	return err;
}

static void sshfs_sync_write_begin(struct request *req)
{
	struct sshfs_io *sio = (struct sshfs_io *) req->data;
	sio->num_reqs++;
}

static void sshfs_sync_write_end(struct request *req)
{
	uint32_t serr;
	struct sshfs_io *sio = (struct sshfs_io *) req->data;

	if (req->error) {
		sio->error = req->error;
	} else if (req->replied) {
		if (req->reply_type != SSH_FXP_STATUS) {
			fprintf(stderr, "protocol error\n");
		} else if (buf_get_uint32(&req->reply, &serr) != -1 &&
			serr != SSH_FX_OK) {
			sio->error = -EIO;
		}
	}
	sio->num_reqs--;
	if (!sio->num_reqs)
		pthread_cond_broadcast(&sio->finished);
}


static int sshfs_sync_write(struct sshfs_file *sf, const char *wbuf,
			    size_t size, off_t offset)
{
	int err = 0;
	struct buffer *handle = &sf->handle;
	struct sshfs_io sio = { .error = 0, .num_reqs = 0 };

	pthread_cond_init(&sio.finished, NULL);

	while (!err && size) {
		struct buffer buf;
		struct iovec iov[2];
		size_t bsize = size < sshfs.max_write ? size : sshfs.max_write;

		buf_init(&buf, 0);
		buf_add_buf(&buf, handle);
		buf_add_uint64(&buf, offset);
		buf_add_uint32(&buf, bsize);
		buf_to_iov(&buf, &iov[0]);
		iov[1].iov_base = (void *) wbuf;
		iov[1].iov_len = bsize;
		err = sftp_request_send(sf->conn, SSH_FXP_WRITE, iov, 2,
					sshfs_sync_write_begin,
					sshfs_sync_write_end,
					0, &sio, NULL);
		buf_free(&buf);
		size -= bsize;
		wbuf += bsize;
		offset += bsize;
	}

	pthread_mutex_lock(&sshfs.lock);
	while (sio.num_reqs)
	       pthread_cond_wait(&sio.finished, &sshfs.lock);
	pthread_mutex_unlock(&sshfs.lock);

	if (!err)
		err = sio.error;

	return err;
}

static int sshfs_write(const char *path, const char *wbuf, size_t size,
                       off_t offset, struct fuse_file_info *fi)
{
	int err;
	struct sshfs_file *sf = get_sshfs_file(fi);

	(void) path;

	if (!sshfs_file_is_conn(sf))
		return -EIO;

	sshfs_inc_modifver();

	if (!sshfs.sync_write && !sf->write_error)
		err = sshfs_async_write(sf, wbuf, size, offset);
	else
		err = sshfs_sync_write(sf, wbuf, size, offset);

	return err ? err : (int) size;
}

static int sshfs_ext_statvfs(const char *path, struct statvfs *stbuf)
{
	int err;
	struct buffer buf;
	struct buffer outbuf;
	buf_init(&buf, 0);
	buf_add_string(&buf, SFTP_EXT_STATVFS);
	buf_add_path(&buf, path);
	err = sftp_request(get_conn(NULL, NULL), SSH_FXP_EXTENDED, &buf,
			   SSH_FXP_EXTENDED_REPLY, &outbuf);
	if (!err) {
		if (buf_get_statvfs(&outbuf, stbuf) == -1)
			err = -EIO;
		buf_free(&outbuf);
	}
	buf_free(&buf);
	return err;
}


static int sshfs_statfs(const char *path, struct statvfs *buf)
{
	if (sshfs.ext_statvfs)
		return sshfs_ext_statvfs(path, buf);

	buf->f_namemax = 255;
	buf->f_bsize = sshfs.blksize;
	/*
	 * df seems to use f_bsize instead of f_frsize, so make them
	 * the same
	 */
	buf->f_frsize = buf->f_bsize;
	buf->f_blocks = buf->f_bfree =  buf->f_bavail =
		1000ULL * 1024 * 1024 * 1024 / buf->f_frsize;
	buf->f_files = buf->f_ffree = 1000000000;
	return 0;
}

static int sshfs_create(const char *path, mode_t mode,
                        struct fuse_file_info *fi)
{
	if (sshfs.createmode_workaround)
		mode = 0;

	return sshfs_open_common(path, mode, fi);
}

static int sshfs_truncate(const char *path, off_t size,
			  struct fuse_file_info *fi)
{
	int err;
	struct buffer buf;
	struct sshfs_file *sf = NULL;

	if (fi != NULL) {
		sf = get_sshfs_file(fi);
		if (!sshfs_file_is_conn(sf))
			return -EIO;
	}

	sshfs_inc_modifver();
	if (sshfs.truncate_workaround)
		return sshfs_truncate_workaround(path, size, fi);

	buf_init(&buf, 0);

	if (sf != NULL)
		buf_add_buf(&buf, &sf->handle);
	else
		buf_add_path(&buf, path);

	buf_add_uint32(&buf, SSH_FILEXFER_ATTR_SIZE);
	buf_add_uint64(&buf, size);
	err = sftp_request(get_conn(sf, path),
			   sf == NULL ? SSH_FXP_SETSTAT : SSH_FXP_FSETSTAT,
			   &buf, SSH_FXP_STATUS, NULL);
	buf_free(&buf);

	return err;
}

static int sshfs_getattr(const char *path, struct stat *stbuf,
			 struct fuse_file_info *fi)
{
	int err;
	struct buffer buf;
	struct buffer outbuf;
	struct sshfs_file *sf = NULL;

	if (fi != NULL && !sshfs.fstat_workaround) {
		sf = get_sshfs_file(fi);
		if (!sshfs_file_is_conn(sf))
			return -EIO;
	}

	buf_init(&buf, 0);
	if(sf == NULL) {
		buf_add_path(&buf, path);
		err = sftp_request(get_conn(sf, path),
				   sshfs.follow_symlinks ? SSH_FXP_STAT : SSH_FXP_LSTAT,
				   &buf, SSH_FXP_ATTRS, &outbuf);
	}
	else {
		buf_add_buf(&buf, &sf->handle);
		err = sftp_request(sf->conn, SSH_FXP_FSTAT, &buf,
				   SSH_FXP_ATTRS, &outbuf);
	}
	if (!err) {
		err = buf_get_attrs(&outbuf, stbuf, NULL);
#ifdef __APPLE__
		stbuf->st_blksize = 0;
#endif
		buf_free(&outbuf);
	}
	buf_free(&buf);
	return err;
}

static int sshfs_truncate_zero(const char *path)
{
	int err;
	struct fuse_file_info fi;

	fi.flags = O_WRONLY | O_TRUNC;
	err = sshfs_open(path, &fi);
	if (!err)
		sshfs_release(path, &fi);

	return err;
}

static size_t calc_buf_size(off_t size, off_t offset)
{
	return offset + sshfs.max_read < size ? sshfs.max_read : size - offset;
}

static int sshfs_truncate_shrink(const char *path, off_t size)
{
	int res;
	char *data;
	off_t offset;
	struct fuse_file_info fi;

	data = calloc(size, 1);
	if (!data)
		return -ENOMEM;

	fi.flags = O_RDONLY;
	res = sshfs_open(path, &fi);
	if (res)
		goto out;

	for (offset = 0; offset < size; offset += res) {
		size_t bufsize = calc_buf_size(size, offset);
		res = sshfs_read(path, data + offset, bufsize, offset, &fi);
		if (res <= 0)
			break;
	}
	sshfs_release(path, &fi);
	if (res < 0)
		goto out;

	fi.flags = O_WRONLY | O_TRUNC;
	res = sshfs_open(path, &fi);
	if (res)
		goto out;

	for (offset = 0; offset < size; offset += res) {
		size_t bufsize = calc_buf_size(size, offset);
		res = sshfs_write(path, data + offset, bufsize, offset, &fi);
		if (res < 0)
			break;
	}
	if (res >= 0)
		res = sshfs_flush(path, &fi);
	sshfs_release(path, &fi);

out:
	free(data);
	return res;
}

static int sshfs_truncate_extend(const char *path, off_t size,
                                 struct fuse_file_info *fi)
{
	int res;
	char c = 0;
	struct fuse_file_info tmpfi;
	struct fuse_file_info *openfi = fi;
	if (!fi) {
		openfi = &tmpfi;
		openfi->flags = O_WRONLY;
		res = sshfs_open(path, openfi);
		if (res)
			return res;
	}
	res = sshfs_write(path, &c, 1, size - 1, openfi);
	if (res == 1)
		res = sshfs_flush(path, openfi);
	if (!fi)
		sshfs_release(path, openfi);

	return res;
}

/*
 * Work around broken sftp servers which don't handle
 * SSH_FILEXFER_ATTR_SIZE in SETSTAT request.
 *
 * If new size is zero, just open the file with O_TRUNC.
 *
 * If new size is smaller than current size, then copy file locally,
 * then open/trunc and send it back.
 *
 * If new size is greater than current size, then write a zero byte to
 * the new end of the file.
 */
static int sshfs_truncate_workaround(const char *path, off_t size,
                                     struct fuse_file_info *fi)
{
	if (size == 0)
		return sshfs_truncate_zero(path);
	else {
		struct stat stbuf;
		int err;
		err = sshfs_getattr(path, &stbuf, fi);
		if (err)
			return err;
		if (stbuf.st_size == size)
			return 0;
		else if (stbuf.st_size > size)
			return sshfs_truncate_shrink(path, size);
		else
			return sshfs_truncate_extend(path, size, fi);
	}
}

static int processing_init(void)
{
	int i;

	signal(SIGPIPE, SIG_IGN);

	pthread_mutex_init(&sshfs.lock, NULL);
	for (i = 0; i < sshfs.max_conns; i++)
		pthread_mutex_init(&sshfs.conns[i].lock_write, NULL);
	pthread_cond_init(&sshfs.outstanding_cond, NULL);
	sshfs.reqtab = g_hash_table_new(NULL, NULL);
	if (!sshfs.reqtab) {
		fprintf(stderr, "failed to create hash table\n");
		return -1;
	}
	if (sshfs.max_conns > 1) {
		sshfs.conntab = g_hash_table_new_full(g_str_hash, g_str_equal,
						      g_free, NULL);
		if (!sshfs.conntab) {
			fprintf(stderr, "failed to create hash table\n");
			return -1;
		}
	}
	return 0;
}

static struct fuse_operations sshfs_oper = {
		.init       = sshfs_init,
		.getattr    = sshfs_getattr,
		.access     = sshfs_access,
		.opendir    = sshfs_opendir,
		.readdir    = sshfs_readdir,
		.releasedir = sshfs_releasedir,
		.readlink   = sshfs_readlink,
		.mknod      = sshfs_mknod,
		.mkdir      = sshfs_mkdir,
		.symlink    = sshfs_symlink,
		.unlink     = sshfs_unlink,
		.rmdir      = sshfs_rmdir,
		.rename     = sshfs_rename,
		.link       = sshfs_link,
		.chmod      = sshfs_chmod,
		.chown      = sshfs_chown,
		.truncate   = sshfs_truncate,
		.utimens    = sshfs_utimens,
		.open       = sshfs_open,
		.flush      = sshfs_flush,
		.fsync      = sshfs_fsync,
		.release    = sshfs_release,
		.read       = sshfs_read,
		.write      = sshfs_write,
		.statfs     = sshfs_statfs,
		.create     = sshfs_create,
};

static void usage(const char *progname)
{
	printf(
"usage: %s [user@]host:[dir] mountpoint [options]\n"
"\n"
"    -h   --help            print help\n"
"    -V   --version         print version\n"
"    -f                     foreground operation\n"
"    -s                     disable multi-threaded operation\n"
"    -p PORT                equivalent to '-o port=PORT'\n"
"    -C                     equivalent to '-o compression=yes'\n"
"    -F ssh_configfile      specifies alternative ssh configuration file\n"
"    -1                     equivalent to '-o ssh_protocol=1'\n"
"    -o opt,[opt...]        mount options\n"
"    -o reconnect           reconnect to server\n"
"    -o delay_connect       delay connection to server\n"
"    -o sshfs_sync          synchronous writes\n"
"    -o no_readahead        synchronous reads (no speculative readahead)\n"
"    -o sync_readdir        synchronous readdir\n"
"    -d, --debug            print some debugging information (implies -f)\n"
"    -v, --verbose          print ssh replies and messages\n"
"    -o dir_cache=BOOL      enable caching of directory contents (names,\n"
"                           attributes, symlink targets) {yes,no} (default: yes)\n"
"    -o dcache_max_size=N   sets the maximum size of the directory cache (default: 10000)\n"
"    -o dcache_timeout=N    sets timeout for directory cache in seconds (default: 20)\n"
"    -o dcache_{stat,link,dir}_timeout=N\n"
"                           sets separate timeout for {attributes, symlinks, names}\n"
"    -o dcache_clean_interval=N\n"
"                           sets the interval for automatic cleaning of the\n"
"                           cache (default: 60)\n"
"    -o dcache_min_clean_interval=N\n"
"                           sets the interval for forced cleaning of the\n"
"                           cache if full (default: 5)\n"
"    -o direct_io           enable direct i/o\n"
"    -o workaround=LIST     colon separated list of workarounds\n"
"             none             no workarounds enabled\n"
"             [no]rename       fix renaming to existing file (default: off)\n"
"             [no]renamexdev   fix moving across filesystems (default: off)\n"
"             [no]truncate     fix truncate for old servers (default: off)\n"
"             [no]buflimit     fix buffer fillup bug in server (default: off)\n"
"             [no]fstat        always use stat() instead of fstat() (default: off)\n"
"             [no]createmode   always pass mode 0 to create (default: off)\n"
"    -o idmap=TYPE          user/group ID mapping (default: " IDMAP_DEFAULT ")\n"
"             none             no translation of the ID space\n"
"             user             only translate UID/GID of connecting user\n"
"             file             translate UIDs/GIDs contained in uidfile/gidfile\n"
"    -o uidfile=FILE        file containing username:remote_uid mappings\n"
"    -o gidfile=FILE        file containing groupname:remote_gid mappings\n"
"    -o nomap=TYPE          with idmap=file, how to handle missing mappings\n"
"             ignore           don't do any re-mapping\n"
"             error            return an error (default)\n"
"    -o ssh_command=CMD     execute CMD instead of 'ssh'\n"
"    -o ssh_protocol=N      ssh protocol to use (default: 2)\n"
"    -o sftp_server=SERV    path to sftp server or subsystem (default: sftp)\n"
"    -o directport=PORT     directly connect to PORT bypassing ssh\n"
"    -o passive             communicate over stdin and stdout bypassing network\n"
"    -o disable_hardlink    link(2) will return with errno set to ENOSYS\n"
"    -o transform_symlinks  transform absolute symlinks to relative\n"
"    -o follow_symlinks     follow symlinks on the server\n"
"    -o no_check_root       don't check for existence of 'dir' on server\n"
"    -o password_stdin      read password from stdin (only for pam_mount!)\n"
"    -o max_conns=N         open parallel SSH connections\n"
"    -o vsock=CID:PORT      connect to the given vsock\n"
"    -o SSHOPT=VAL          ssh options (see man ssh_config)\n"
"\n"
"FUSE Options:\n",
progname);
}

static int is_ssh_opt(const char *arg)
{
	if (arg[0] != '-') {
		unsigned arglen = strlen(arg);
		const char **o;
		for (o = ssh_opts; *o; o++) {
			unsigned olen = strlen(*o);
			if (arglen > olen && arg[olen] == '=' &&
			    strncasecmp(arg, *o, olen) == 0)
				return 1;
		}
	}
	return 0;
}

static int sshfs_opt_proc(void *data, const char *arg, int key,
                          struct fuse_args *outargs)
{
	(void) outargs; (void) data;
	char *tmp;

	switch (key) {
	case FUSE_OPT_KEY_OPT:
		if (is_ssh_opt(arg)) {
			tmp = g_strdup_printf("-o%s", arg);
			ssh_add_arg(tmp);
			g_free(tmp);
			return 0;
		}
		/* Pass through */
		return 1;

	case FUSE_OPT_KEY_NONOPT:
		if (!sshfs.host && strchr(arg, ':')) {
			sshfs.host = strdup(arg);
			return 0;
		}
		else if (!sshfs.mountpoint) {
#if defined(__CYGWIN__)
			/*
			 * On FUSE for Cygwin the mountpoint may be a drive or directory.
			 * Furthermore the mountpoint must NOT exist prior to mounting.
			 * So we cannot use realpath(3).
			 */
			if ((('A' <= arg[0] && arg[0] <= 'Z') || ('a' <= arg[0] && arg[0] <= 'z'))
				&& ':' == arg[1] && '\0' == arg[2]) {
				/* drive: make a copy */
				sshfs.mountpoint = strdup(arg);
			} else {
				/* path: split into dirname, basename and check dirname */
				char *dir;
				const char *base;
				const char *slash = strrchr(arg, '/');
				if (slash) {
					char *tmp = strndup(arg, slash == arg ? 1 : slash - arg);
					dir = tmp ? realpath(tmp, NULL) : 0;
					base = slash + 1;
					free(tmp);
				} else {
					dir = realpath(".", NULL);
					base = arg;
				}
				if (dir) {
					slash = '/' == dir[0] && '\0' == dir[1] ? "" : "/";
					asprintf(&sshfs.mountpoint, "%s%s%s", dir, slash, base);
					free(dir);
				}
			}
#else
			int fd, len;
			if (sscanf(arg, "/dev/fd/%u%n", &fd, &len) == 1 &&
			    len == strlen(arg)) {
				/*
				 * Allow /dev/fd/N unchanged; it can be
				 * use for pre-mounting a generic fuse
				 * mountpoint to later be completely
				 * unprivileged with libfuse >= 3.3.0.
				 */
				sshfs.mountpoint = strdup(arg);
			} else {
				sshfs.mountpoint = realpath(arg, NULL);
			}
#endif
			if (!sshfs.mountpoint) {
				fprintf(stderr, "sshfs: bad mount point `%s': %s\n",
					arg, strerror(errno));
				return -1;
			}
			return 0;
		}
		fprintf(stderr, "sshfs: invalid argument `%s'\n", arg);
		return -1;


	case KEY_PORT:
		tmp = g_strdup_printf("-oPort=%s", arg + 2);
		ssh_add_arg(tmp);
		g_free(tmp);
		return 0;

	case KEY_COMPRESS:
		ssh_add_arg("-oCompression=yes");
		return 0;

	case KEY_CONFIGFILE:
		tmp = g_strdup_printf("-F%s", arg + 2);
		ssh_add_arg(tmp);
		g_free(tmp);
		return 0;

	default:
		fprintf(stderr, "internal error\n");
		abort();
	}
}

static int workaround_opt_proc(void *data, const char *arg, int key,
			       struct fuse_args *outargs)
{
	(void) data; (void) key; (void) outargs;
	fprintf(stderr, "unknown workaround: '%s'\n", arg);
	return -1;
}

static int parse_workarounds(void)
{
	int res;
	/* Need separate variables because literals are const
	   char */
	char argv0[] = "";
	char argv1[] = "-o";
	char *argv[] = { argv0, argv1, sshfs.workarounds, NULL };
	struct fuse_args args = FUSE_ARGS_INIT(3, argv);
	char *s = sshfs.workarounds;
	if (!s)
		return 0;

	while ((s = strchr(s, ':')))
		*s = ',';

	res = fuse_opt_parse(&args, &sshfs, workaround_opts,
			     workaround_opt_proc);
	fuse_opt_free_args(&args);

	return res;
}

static int read_password(void)
{
	int size = getpagesize();
	int max_password = MIN(MAX_PASSWORD, size - 1);
	int n;

	sshfs.password = mmap(NULL, size, PROT_READ | PROT_WRITE,
			      MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED,
			      -1, 0);
	if (sshfs.password == MAP_FAILED) {
		perror("Failed to allocate locked page for password");
		return -1;
	}
	if (mlock(sshfs.password, size) != 0) {
		memset(sshfs.password, 0, size);
		munmap(sshfs.password, size);
		sshfs.password = NULL;
		perror("Failed to allocate locked page for password");
		return -1;
	}

	/* Don't use fgets() because password might stay in memory */
	for (n = 0; n < max_password; n++) {
		int res;

		res = read(0, &sshfs.password[n], 1);
		if (res == -1) {
			perror("Reading password");
			return -1;
		}
		if (res == 0) {
			sshfs.password[n] = '\n';
			break;
		}
		if (sshfs.password[n] == '\n')
			break;
	}
	if (n == max_password) {
		fprintf(stderr, "Password too long\n");
		return -1;
	}
	sshfs.password[n+1] = '\0';
	ssh_add_arg("-oNumberOfPasswordPrompts=1");

	return 0;
}

// Behaves similarly to strtok(), but allows for the ' ' delimiter to be escaped
// by '\ '.
static char *tokenize_on_space(char *str)
{
	static char *pos = NULL;
	char *start = NULL;

	if (str)
		pos = str;

	if (!pos)
		return NULL;

	// trim any leading spaces
	while (*pos == ' ')
		pos++;

	start = pos;

	while (pos && *pos != '\0') {
		// break on space, but not on '\ '
		if (*pos == ' ' && *(pos - 1) != '\\') {
			break;
		}
		pos++;
	}

	if (*pos == '\0') {
		pos = NULL;
	}
	else {
		*pos = '\0';
		pos++;
	}

	return start;
}

static void set_ssh_command(void)
{
	char *token = NULL;
	int i = 0;

	token = tokenize_on_space(sshfs.ssh_command);
	while (token != NULL) {
		if (i == 0) {
			replace_arg(&sshfs.ssh_args.argv[0], token);
		} else {
			if (fuse_opt_insert_arg(&sshfs.ssh_args, i, token) == -1)
				_exit(1);
		}
		i++;

		token = tokenize_on_space(NULL);
	}
}

static char *find_base_path(void)
{
	char *s = sshfs.host;
	char *d = s;

	for (; *s && *s != ':'; s++) {
		if (*s == '[') {
			/*
			 * Handle IPv6 numerical address enclosed in square
			 * brackets
			 */
			s++;
			for (; *s != ']'; s++) {
				if (!*s) {
					fprintf(stderr,	"missing ']' in hostname\n");
					exit(1);
				}
				*d++ = *s;
			}
		} else {
			*d++ = *s;
		}

	}
	*d++ = '\0';
	s++;

	return s;
}

static char *fsname_escape_commas(char *fsnameold)
{
	char *fsname = g_malloc(strlen(fsnameold) * 2 + 1);
	char *d = fsname;
	char *s;

	for (s = fsnameold; *s; s++) {
		if (*s == '\\' || *s == ',')
			*d++ = '\\';
		*d++ = *s;
	}
	*d = '\0';
	g_free(fsnameold);

	return fsname;
}

static int ssh_connect(void)
{
	int res;

	res = processing_init();
	if (res == -1)
		return -1;

	if (!sshfs.delay_connect) {
		if (connect_remote(&sshfs.conns[0]) == -1)
			return -1;

		if (!sshfs.no_check_root &&
		    sftp_check_root(&sshfs.conns[0], sshfs.base_path) != 0)
			return -1;

	}
	return 0;
}

/* number of ':' separated fields in a passwd/group file that we care
 * about */
#define IDMAP_FIELDS 3

/* given a line from a uidmap or gidmap, parse out the name and id */
static void parse_idmap_line(char *line, const char* filename,
		const unsigned int lineno, uint32_t *ret_id, char **ret_name,
		const int eof)
{
	/* chomp off the trailing newline */
	char *p = line;
	if ((p = strrchr(line, '\n')))
		*p = '\0';
	else if (!eof) {
		fprintf(stderr, "%s:%u: line too long\n", filename, lineno);
		exit(1);
	}
	char *tokens[IDMAP_FIELDS];
	char *tok;
	int i;
	for (i = 0; (tok = strsep(&line, ":")) && (i < IDMAP_FIELDS) ; i++) {
		tokens[i] = tok;
	}

	char *name_tok, *id_tok;
	if (i == 2) {
		/* assume name:id format */
		name_tok = tokens[0];
		id_tok = tokens[1];
	} else if (i >= IDMAP_FIELDS) {
		/* assume passwd/group file format */
		name_tok = tokens[0];
		id_tok = tokens[2];
	} else {
		fprintf(stderr, "%s:%u: unknown format\n", filename, lineno);
		exit(1);
	}

	errno = 0;
	uint32_t remote_id = strtoul(id_tok, NULL, 10);
	if (errno) {
		fprintf(stderr, "Invalid id number on line %u of '%s': %s\n",
				lineno, filename, strerror(errno));
		exit(1);
	}

	*ret_name = strdup(name_tok);
	*ret_id = remote_id;
}

/* read a uidmap or gidmap */
static void read_id_map(char *file, uint32_t *(*map_fn)(char *),
		const char *name_id, GHashTable **idmap, GHashTable **r_idmap)
{
	*idmap = g_hash_table_new(NULL, NULL);
	*r_idmap = g_hash_table_new(NULL, NULL);
	FILE *fp;
	char line[LINE_MAX];
	unsigned int lineno = 0;
	uid_t local_uid = getuid();

	fp = fopen(file, "r");
	if (fp == NULL) {
		fprintf(stderr, "failed to open '%s': %s\n",
				file, strerror(errno));
		exit(1);
	}
	struct stat st;
	if (fstat(fileno(fp), &st) == -1) {
		fprintf(stderr, "failed to stat '%s': %s\n", file,
				strerror(errno));
		exit(1);
	}
	if (st.st_uid != local_uid) {
		fprintf(stderr, "'%s' is not owned by uid %lu\n", file,
				(unsigned long)local_uid);
		exit(1);
	}
	if (st.st_mode & S_IWGRP || st.st_mode & S_IWOTH) {
		fprintf(stderr, "'%s' is writable by other users\n", file);
		exit(1);
	}

	while (fgets(line, LINE_MAX, fp) != NULL) {
		lineno++;
		uint32_t remote_id;
		char *name;

		/* skip blank lines */
		if (line[0] == '\n' || line[0] == '\0')
			continue;

		parse_idmap_line(line, file, lineno, &remote_id, &name, feof(fp));

		uint32_t *local_id = map_fn(name);
		if (local_id == NULL) {
			/* not found */
			DEBUG("%s(%u): no local %s\n", name, remote_id, name_id);
			free(name);
			continue;
		}

		DEBUG("%s: remote %s %u => local %s %u\n",
				name, name_id, remote_id, name_id, *local_id);
		g_hash_table_insert(*idmap, GUINT_TO_POINTER(remote_id), GUINT_TO_POINTER(*local_id));
		g_hash_table_insert(*r_idmap, GUINT_TO_POINTER(*local_id), GUINT_TO_POINTER(remote_id));
		free(name);
		free(local_id);
	}

	if (fclose(fp) == EOF) {
		fprintf(stderr, "failed to close '%s': %s",
				file, strerror(errno));
		exit(1);
	}
}

/* given a username, return a pointer to its uid, or NULL if it doesn't
 * exist on this system */
static uint32_t *username_to_uid(char *name)
{
	errno = 0;
	struct passwd *pw = getpwnam(name);
	if (pw == NULL) {
		if (errno == 0) {
			/* "does not exist" */
			return NULL;
		}
		fprintf(stderr, "Failed to look up user '%s': %s\n",
				name, strerror(errno));
		exit(1);
	}
	uint32_t *r = malloc(sizeof(uint32_t));
	if (r == NULL) {
		fprintf(stderr, "sshfs: memory allocation failed\n");
		abort();
	}
	*r = pw->pw_uid;
	return r;
}

/* given a groupname, return a pointer to its gid, or NULL if it doesn't
 * exist on this system */
static uint32_t *groupname_to_gid(char *name)
{
	errno = 0;
	struct group *gr = getgrnam(name);
	if (gr == NULL) {
		if (errno == 0) {
			/* "does not exist" */
			return NULL;
		}
		fprintf(stderr, "Failed to look up group '%s': %s\n",
				name, strerror(errno));
		exit(1);
	}
	uint32_t *r = malloc(sizeof(uint32_t));
	if (r == NULL) {
		fprintf(stderr, "sshfs: memory allocation failed\n");
		abort();
	}
	*r = gr->gr_gid;
	return r;
}

static inline void load_uid_map(void)
{
	read_id_map(sshfs.uid_file, &username_to_uid, "uid", &sshfs.uid_map, &sshfs.r_uid_map);
}

static inline void load_gid_map(void)
{
	read_id_map(sshfs.gid_file, &groupname_to_gid, "gid", &sshfs.gid_map, &sshfs.r_gid_map);
}

#ifdef __APPLE__
int main(int argc, char *argv[], __unused char *envp[], char **exec_path)
#else
int main(int argc, char *argv[])
#endif
{
	int res;
	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
	char *tmp;
	char *fsname;
	const char *sftp_server;
	struct fuse *fuse;
	struct fuse_session *se;
	int i;

#ifdef __APPLE__
	if (!realpath(*exec_path, sshfs_program_path)) {
		memset(sshfs_program_path, 0, PATH_MAX);
	}
#endif /* __APPLE__ */

#ifdef __APPLE__
	sshfs.blksize = 0;
#else
	sshfs.blksize = 4096;
#endif
	/* SFTP spec says all servers should allow at least 32k I/O */
	sshfs.max_read = 32768;
	sshfs.max_write = 32768;
#ifdef __APPLE__
	sshfs.rename_workaround = 1;
#else
	sshfs.rename_workaround = 0;
#endif
	sshfs.renamexdev_workaround = 0;
	sshfs.truncate_workaround = 0;
	sshfs.buflimit_workaround = 0;
	sshfs.createmode_workaround = 0;
	sshfs.ssh_ver = 2;
	sshfs.progname = argv[0];
	sshfs.max_conns = 1;
	sshfs.ptyfd = -1;
	sshfs.dir_cache = 1;
	sshfs.show_help = 0;
	sshfs.show_version = 0;
	sshfs.singlethread = 0;
	sshfs.foreground = 0;
	sshfs.ptypassivefd = -1;
	sshfs.delay_connect = 0;
	sshfs.passive = 0;
	sshfs.detect_uid = 0;
	if (strcmp(IDMAP_DEFAULT, "none") == 0) {
		sshfs.idmap = IDMAP_NONE;
	} else if (strcmp(IDMAP_DEFAULT, "user") == 0) {
		sshfs.idmap = IDMAP_USER;
	} else {
		fprintf(stderr, "bad idmap default value built into sshfs; "
		    "assuming none (bad logic in configure script?)\n");
		sshfs.idmap = IDMAP_NONE;
	}
	sshfs.nomap = NOMAP_ERROR;
	ssh_add_arg("ssh");
	ssh_add_arg("-x");
	ssh_add_arg("-a");
	ssh_add_arg("-oClearAllForwardings=yes");

	if (fuse_opt_parse(&args, &sshfs, sshfs_opts, sshfs_opt_proc) == -1 ||
	    parse_workarounds() == -1)
		exit(1);

	if (sshfs.show_version) {
		printf("SSHFS version %s\n", PACKAGE_VERSION);
		printf("FUSE library version %s\n", fuse_pkgversion());
#if !defined(__CYGWIN__)
		fuse_lowlevel_version();
#endif
		exit(0);
	}

	if (sshfs.show_help) {
		usage(args.argv[0]);
		fuse_lib_help(&args);
		exit(0);
	} else if (!sshfs.host) {
		fprintf(stderr, "missing host\n");
		fprintf(stderr, "see `%s -h' for usage\n", argv[0]);
		exit(1);
	} else if (!sshfs.mountpoint) {
		fprintf(stderr, "error: no mountpoint specified\n");
		fprintf(stderr, "see `%s -h' for usage\n", argv[0]);
		exit(1);
	}

	if (sshfs.idmap == IDMAP_USER)
		sshfs.detect_uid = 1;
	else if (sshfs.idmap == IDMAP_FILE) {
		sshfs.uid_map = NULL;
		sshfs.gid_map = NULL;
		sshfs.r_uid_map = NULL;
		sshfs.r_gid_map = NULL;
		if (!sshfs.uid_file && !sshfs.gid_file) {
			fprintf(stderr, "need a uidfile or gidfile with idmap=file\n");
			exit(1);
		}
		if (sshfs.uid_file)
			load_uid_map();
		if (sshfs.gid_file)
			load_gid_map();
	}
	free(sshfs.uid_file);
	free(sshfs.gid_file);

	DEBUG("SSHFS version %s\n", PACKAGE_VERSION);

	/* Force sshfs to the foreground when using stdin+stdout */
	if (sshfs.passive)
		sshfs.foreground = 1;


	if (sshfs.passive && sshfs.password_stdin) {
		fprintf(stderr, "the password_stdin and passive options cannot both be specified\n");
		exit(1);
	}

	if (sshfs.password_stdin) {
		res = read_password();
		if (res == -1)
			exit(1);
	}

	if (sshfs.debug)
		sshfs.foreground = 1;

	if (sshfs.buflimit_workaround)
		/* Work around buggy sftp-server in OpenSSH.  Without this on
		   a slow server a 10Mbyte buffer would fill up and the server
		   would abort */
		sshfs.max_outstanding_len = 8388608;
	else
		sshfs.max_outstanding_len = ~0;

	if (sshfs.max_conns > 1) {
		if (sshfs.buflimit_workaround) {
			fprintf(stderr, "buflimit workaround is not supported with parallel connections\n");
			exit(1);
		}

		if (sshfs.password_stdin) {
			fprintf(stderr, "password_stdin option cannot be specified with parallel connections\n");
			exit(1);
		}

		if (sshfs.passive) {
			fprintf(stderr, "passive option cannot be specified with parallel connections\n");
			exit(1);
		}
	} else if (sshfs.max_conns <= 0) {
		fprintf(stderr, "value of max_conns option must be at least 1\n");
		exit(1);
	}

	sshfs.conns = g_new0(struct conn, sshfs.max_conns);
	for (i = 0; i < sshfs.max_conns; i++) {
		sshfs.conns[i].rfd = -1;
		sshfs.conns[i].wfd = -1;
	}

	fsname = g_strdup(sshfs.host);
	sshfs.base_path = g_strdup(find_base_path());

	if (sshfs.ssh_command)
		set_ssh_command();

	tmp = g_strdup_printf("-%i", sshfs.ssh_ver);
	ssh_add_arg(tmp);
	g_free(tmp);
	ssh_add_arg(sshfs.host);
	if (sshfs.sftp_server)
		sftp_server = sshfs.sftp_server;
	else if (sshfs.ssh_ver == 1)
		sftp_server = SFTP_SERVER_PATH;
	else
		sftp_server = "sftp";

	if (sshfs.ssh_ver != 1 && strchr(sftp_server, '/') == NULL)
		ssh_add_arg("-s");

	ssh_add_arg(sftp_server);
	free(sshfs.sftp_server);

	res = cache_parse_options(&args);
	if (res == -1)
		exit(1);

	sshfs.randseed = time(0);

	if (sshfs.max_read > 65536)
		sshfs.max_read = 65536;
	if (sshfs.max_write > 65536)
		sshfs.max_write = 65536;

	fsname = fsname_escape_commas(fsname);
	tmp = g_strdup_printf("-osubtype=sshfs,fsname=%s", fsname);
	fuse_opt_insert_arg(&args, 1, tmp);
	g_free(tmp);
	g_free(fsname);

	if(sshfs.dir_cache)
		sshfs.op = cache_wrap(&sshfs_oper);
	else
		sshfs.op = &sshfs_oper;
	fuse = fuse_new(&args, sshfs.op,
			sizeof(struct fuse_operations), NULL);
	if(fuse == NULL)
		exit(1);
	se = fuse_get_session(fuse);
	res = fuse_set_signal_handlers(se);
	if (res != 0) {
		fuse_destroy(fuse);
		exit(1);
	}

	res = fuse_mount(fuse, sshfs.mountpoint);
	if (res != 0) {
		fuse_destroy(fuse);
		exit(1);
	}

#if !defined(__CYGWIN__)
	res = fcntl(fuse_session_fd(se), F_SETFD, FD_CLOEXEC);
	if (res == -1)
		perror("WARNING: failed to set FD_CLOEXEC on fuse device");
#endif

	/*
	 * FIXME: trim $PATH so it doesn't contain anything inside the
	 * mountpoint, which would deadlock.
	 */
	res = ssh_connect();
	if (res == -1) {
		fuse_unmount(fuse);
		fuse_destroy(fuse);
		exit(1);
	}

	res = fuse_daemonize(sshfs.foreground);
	if (res == -1) {
		fuse_unmount(fuse);
		fuse_destroy(fuse);
		exit(1);
	}

	if (sshfs.singlethread)
		res = fuse_loop(fuse);
	else
		res = fuse_loop_mt(fuse, 0);

	if (res != 0)
		res = 1;
	else
		res = 0;

	fuse_remove_signal_handlers(se);
	fuse_unmount(fuse);
	fuse_destroy(fuse);

	if (sshfs.debug) {
		unsigned int avg_rtt = 0;

		if (sshfs.num_sent)
			avg_rtt = sshfs.total_rtt / sshfs.num_sent;

		DEBUG("\n"
		      "sent:               %llu messages, %llu bytes\n"
		      "received:           %llu messages, %llu bytes\n"
		      "rtt min/max/avg:    %ums/%ums/%ums\n"
		      "num connect:        %u\n",
		      (unsigned long long) sshfs.num_sent,
		      (unsigned long long) sshfs.bytes_sent,
		      (unsigned long long) sshfs.num_received,
		      (unsigned long long) sshfs.bytes_received,
		      sshfs.min_rtt, sshfs.max_rtt, avg_rtt,
		      sshfs.num_connect);
	}

	fuse_opt_free_args(&args);
	fuse_opt_free_args(&sshfs.ssh_args);
	free(sshfs.directport);

	return res;
}