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syscalls-rs

This library is an attempt to remove the libc dependency from rust with x86_64-unknown-linux-bare (and the same for the rest of tier 1 platforms)

Open Questions

  1. How much should we aim to make the syscalls "safe"?(i.e. not unsafe fn)
  2. Should we provide syscalls only or library functions too? (only 2, or also 3?)
  3. If not then where should (3) be defined/implemented?
  4. How much should they be compatible with glibc? (i.e. threads?)
  5. Should we provide enums for the flags? or should the flag stay ints?
  6. Minimum Supported kernel version. how?. which?.
  7. Should we have our own types? (i.e. FileDescriptor type) traits?.
  8. fnctl: according to the man page However, these details can be ignored by applications using glibc,whose fcntl() wrapper function transparently employs the more recentsystem call where it is available. looking at glibc code it does some work and then calls fcntl64. should we just only implement fcntl64? should we wrap that?
  9. glibc uses SYSCALL_CANCEL which calls LIBC_CANCEL_ASYNC incase of multithreading. should we look into that? what are the implications of this?
  10. Should we split some syscalls into multiple functions? i.e. we could split fnctl into a function where the third argument is(*mut flock) and one where it's an int(and one without a third argument).
  11. Should we use bitflags? https://docs.rs/bitflags
  12. Should we feature gate per linux kernel version? Is there a way to check this at compile/runtime? (for new features).
  13. Should we split the high level syscalls into a files/net etc. modules?.
  14. glibc seems to use fnctl for dup*. what should we do?.
  15. setuid by itself isn't thread safe, glibc uses INLINE_SETXID_SYSCALL and musl __setxid, what should we do?

Guidelines (For now - IMHO)

  1. This library should only expose syscalls for Linux 3.2+ for now rust-lang/libc#1412 (comment).
  2. If there are advanced functions and subset of those we should expose the most advanced and make a wrapper for the most common one that calls the advanced. (e.g. rename/renameat/renameat2).
  3. Try to gain the most safety possible if it's zero cost. if not a case by case consideration is required. (preferably compile time safety).

List of syscalls used in rust/src/libstd:

Kernel Calls(2)

  • ftruncate
  • pread
  • pwrite
  • gettimeofday
  • connect
  • getsockname
  • getpeername
  • bind
  • listen
  • recvfrom
  • sendto
  • read
  • readv
  • pread64
  • write
  • pwrite64
  • pwrite
  • fcntl
  • ioctl
  • close
  • stat64
  • fstat64
  • lstat64
  • ftruncate64
  • lseek64
  • dirent64
  • open64
  • fstatat64
  • stat
  • fstat
  • fstatat
  • lstat
  • dirent
  • open
  • fdatasync
  • fsync
  • fchmod
  • mkdir
  • unlink
  • rename
  • chmod
  • rmdir
  • readlink
  • symlink
  • link
  • syscall (We really shouldn't provide this)
  • signal
  • [c] socket
  • socketpair
  • poll
  • accept
  • shutdown
  • chdir
  • getuid
  • getpid
  • getppid
  • pipe2
  • pipe
  • kill
  • fork
  • _exit
  • dup2
  • setgid
  • setgroups
  • setuid
  • waitpid
  • WIFEXITED
  • WEXITSTATUS
  • WTERMSIG
  • getrandom
  • sigaltstack
  • sigaction
  • mmap
  • munmap
  • sched_yield
  • prctl
  • nanosleep
  • mprotect
  • accept4
  • copy_file_range

glibc implemented(3)

  • exit
  • strlen
  • unsetenv
  • setenv
  • getenv
  • environ(7)?
  • strerror_r
  • abort
  • malloc
  • calloc
  • free
  • realloc
  • memalign
  • posix_memalign
  • clock_gettime
  • dirfd
  • readdir
  • closedir
  • opendir
  • realpath
  • memchr
  • gai_strerror
  • res_init
  • getcwd
  • sysconf
  • getpwuid_r
  • gnu_get_libc_version
  • sigemptyset
  • sigaddset
  • execvp
  • posix_spawn_file_actions_destroy
  • posix_spawnattr_destroy
  • posix_spawnattr_init
  • posix_spawn_file_actions_init
  • posix_spawn_file_actions_adddup2
  • posix_spawnattr_setsigmask
  • posix_spawnattr_setsigdefault
  • posix_spawnattr_setflags
  • posix_spawnp
  • dlsym

pthreads

  • pthread_condattr_init
  • pthread_condattr_setclock
  • pthread_cond_init
  • pthread_condattr_destroy
  • pthread_cond_signal
  • pthread_cond_broadcast
  • pthread_cond_wait
  • pthread_cond_timedwait
  • pthread_cond_destroy
  • pthread_mutexattr_init
  • pthread_mutexattr_settype
  • pthread_mutex_init
  • pthread_mutexattr_destroy
  • pthread_mutex_lock
  • pthread_mutex_unlock
  • pthread_mutex_trylock
  • pthread_mutex_destroy
  • pthread_sigmask
  • pthread_rwlock_rdlock
  • pthread_rwlock_tryrdlock
  • pthread_rwlock_wrlock
  • pthread_rwlock_trywrlock
  • pthread_rwlock_unlock
  • pthread_rwlock_destroy
  • pthread_key_create
  • pthread_setspecific
  • pthread_getspecific
  • pthread_key_delete
  • pthread_attr_setstacksize
  • pthread_attr_init
  • pthread_create
  • pthread_attr_destroy
  • pthread_set_name_np
  • pthread_setname_np
  • pthread_self
  • pthread_join
  • pthread_detach
  • pthread_getattr_np
  • pthread_attr_getguardsize
  • pthread_attr_getstack

Other

  • sysctl