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blaze_util_windows: use some widechar Win32 API
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In this change:
- implement PrintErrorW (copy of PrintError but
uses FormatMessageW)
- use GetModuleFileNameW in GetSelfPath and do not
worry about UNC paths, we'll automatically handle
them in the future when we use widechar
functions everywhere. Until then, if a path
happens to have the "\\?\" prefix and that causes
an error, we won't be worse off than today; today
we just call `pdie`
- use GetTempPathW in GetOutputRoot; in theory
this might also return an UNC path but again that
shouldn't be a problem
- add comments for the arguments of CreateFileA
and CreateProcessA calls, to make the code a bit
more readable

See #2181

--
PiperOrigin-RevId: 142118854
MOS_MIGRATED_REVID=142118854
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@laszlocsomor @katre
laszlocsomor authored and katre committed Dec 15, 2016
1 parent 8dd6ee6 commit 31500b8
Showing 1 changed file with 95 additions and 74 deletions.
169 changes: 95 additions & 74 deletions src/main/cpp/blaze_util_windows.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -29,9 +29,10 @@

#include <windows.h>

#include <cstdlib>
#include <cstdio>
#include <cstdlib>
#include <thread> // NOLINT (to slience Google-internal linter)
#include <type_traits> // static_assert

#include "src/main/cpp/blaze_util.h"
#include "src/main/cpp/blaze_util_platform.h"
Expand All @@ -47,10 +48,20 @@

namespace blaze {

// Ensure we can safely cast (const) wchar_t* to LP(C)WSTR.
// This is true with MSVC but usually not with GCC.
static_assert(sizeof(wchar_t) == sizeof(WCHAR),
"wchar_t and WCHAR should be the same size");

// When using widechar Win32 API functions the maximum path length is 32K.
// Add 4 characters for potential UNC prefix and a couple more for safety.
static const size_t kWindowsPathBufferSize = 0x8010;

using blaze_util::die;
using blaze_util::pdie;
using std::string;
using std::vector;
using std::wstring;

SignalHandler SignalHandler::INSTANCE;

Expand Down Expand Up @@ -220,6 +231,28 @@ static void PrintError(const string& op) {
LocalFree(message_buffer);
}

static void PrintErrorW(const wstring& op) {
DWORD last_error = ::GetLastError();
if (last_error == 0) {
return;
}

WCHAR* message_buffer;
FormatMessageW(
/* dwFlags */ FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
/* lpSource */ nullptr,
/* dwMessageId */ last_error,
/* dwLanguageId */ MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
/* lpBuffer */ message_buffer,
/* nSize */ 0,
/* Arguments */ nullptr);

fwprintf(stderr, L"ERROR: %s: %s (%d)\n", op.c_str(), message_buffer,
last_error);
LocalFree(message_buffer);
}

void WarnFilesystemType(const string& output_base) {
}

Expand All @@ -228,37 +261,27 @@ string GetProcessIdAsString() {
}

string GetSelfPath() {
#ifdef COMPILER_MSVC
const size_t PATH_MAX = 4096;
#endif // COMPILER_MSVC
char buffer[PATH_MAX] = {};
if (!GetModuleFileNameA(0, buffer, sizeof(buffer))) {
WCHAR buffer[kWindowsPathBufferSize] = {0};
if (!GetModuleFileNameW(0, buffer, kWindowsPathBufferSize)) {
pdie(255, "Error %u getting executable file name\n", GetLastError());
}

// TODO(bazel-team): Implement proper handling for UNC paths
// (e.g. "\\?\C:\foo\bar") instead of erroring out when we see them.
if (strlen(buffer) == 0 || buffer[0] == '\\') {
PrintError("GetModuleFileName");
buffer[PATH_MAX - 1] = '\0';
pdie(255, "Error in GetSelfPath, buffer=(%s)", buffer);
}
return string(buffer);
return string(blaze_util::WstringToCstring(buffer).get());
}

string GetOutputRoot() {
#ifdef COMPILER_MSVC
// GetTempPathA and GetEnvironmentVariableA only work properly when Bazel
// GetTempPathW and GetEnvironmentVariableW only work properly when Bazel
// runs under cmd.exe, not when it's run from msys.
// We don't know the reason for this; what's sure is GetEnvironmentVariableA
// returns nothing for TEMP under msys, though it can retrieve WINDIR.
// The reason is that MSYS consumes all environment variables and sets its own
// ones. The symptom of this is that GetEnvironmentVariableW returns nothing
// for TEMP under MSYS, though it can retrieve WINDIR.

char buf[MAX_PATH + 1];
if (!GetTempPathA(sizeof(buf), buf)) {
PrintError("GetTempPath");
WCHAR buffer[kWindowsPathBufferSize] = {0};
if (!GetTempPathW(kWindowsPathBufferSize, buffer)) {
PrintErrorW(L"GetTempPathW");
pdie(255, "Could not retrieve the temp directory path");
}
return buf;
return string(blaze_util::WstringToCstring(buffer).get());
#else // not COMPILER_MSVC
for (const char* i : {"TMPDIR", "TEMPDIR", "TMP", "TEMP"}) {
char* tmpdir = getenv(i);
Expand Down Expand Up @@ -429,18 +452,17 @@ string RunProgram(
CmdLine cmdline;
CreateCommandLine(&cmdline, exe, args_vector);

bool ok = CreateProcessA(
NULL, // _In_opt_ LPCTSTR lpApplicationName,
// _Inout_opt_ LPTSTR lpCommandLine,
cmdline.cmdline,
NULL, // _In_opt_ LPSECURITY_ATTRIBUTES lpProcessAttributes,
NULL, // _In_opt_ LPSECURITY_ATTRIBUTES lpThreadAttributes,
true, // _In_ BOOL bInheritHandles,
0, // _In_ DWORD dwCreationFlags,
NULL, // _In_opt_ LPVOID lpEnvironment,
NULL, // _In_opt_ LPCTSTR lpCurrentDirectory,
&startupInfo, // _In_ LPSTARTUPINFO lpStartupInfo,
&processInfo); // _Out_ LPPROCESS_INFORMATION lpProcessInformation
BOOL ok = CreateProcessA(
/* lpApplicationName */ NULL,
/* lpCommandLine */ cmdline.cmdline,
/* lpProcessAttributes */ NULL,
/* lpThreadAttributes */ NULL,
/* bInheritHandles */ TRUE,
/* dwCreationFlags */ 0,
/* lpEnvironment */ NULL,
/* lpCurrentDirectory */ NULL,
/* lpStartupInfo */ &startupInfo,
/* lpProcessInformation */ &processInfo);

if (!ok) {
pdie(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
Expand Down Expand Up @@ -527,14 +549,14 @@ void ExecuteDaemon(const string& exe, const std::vector<string>& args_vector,
sa.lpSecurityDescriptor = NULL;

HANDLE output_file = CreateFileA(
ConvertPath(daemon_output).c_str(), // lpFileName
GENERIC_READ | GENERIC_WRITE, // dwDesiredAccess
/* lpFileName */ ConvertPath(daemon_output).c_str(),
/* dwDesiredAccess */ GENERIC_READ | GENERIC_WRITE,
// So that the file can be read while the server is running
FILE_SHARE_READ, // dwShareMode
&sa, // lpSecurityAttributes
CREATE_ALWAYS, // dwCreationDisposition
FILE_ATTRIBUTE_NORMAL, // dwFlagsAndAttributes
NULL); // hTemplateFile
/* dwShareMode */ FILE_SHARE_READ,
/* lpSecurityAttributes */ &sa,
/* dwCreationDisposition */ CREATE_ALWAYS,
/* dwFlagsAndAttributes */ FILE_ATTRIBUTE_NORMAL,
/* hTemplateFile */ NULL);

if (output_file == INVALID_HANDLE_VALUE) {
pdie(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR, "CreateFile");
Expand Down Expand Up @@ -564,19 +586,17 @@ void ExecuteDaemon(const string& exe, const std::vector<string>& args_vector,
// environment variables.
SetEnvironmentVariableA("BAZEL_SH", getenv("BAZEL_SH"));

bool ok = CreateProcessA(
NULL, // _In_opt_ LPCTSTR lpApplicationName,
// _Inout_opt_ LPTSTR lpCommandLine,
cmdline.cmdline,
NULL, // _In_opt_ LPSECURITY_ATTRIBUTES lpProcessAttributes,
NULL, // _In_opt_ LPSECURITY_ATTRIBUTES lpThreadAttributes,
TRUE, // _In_ BOOL bInheritHandles,
// _In_ DWORD dwCreationFlags,
DETACHED_PROCESS | CREATE_NEW_PROCESS_GROUP,
NULL, // _In_opt_ LPVOID lpEnvironment,
NULL, // _In_opt_ LPCTSTR lpCurrentDirectory,
&startupInfo, // _In_ LPSTARTUPINFO lpStartupInfo,
&processInfo); // _Out_ LPPROCESS_INFORMATION lpProcessInformation
BOOL ok = CreateProcessA(
/* lpApplicationName */ NULL,
/* lpCommandLine */ cmdline.cmdline,
/* lpProcessAttributes */ NULL,
/* lpThreadAttributes */ NULL,
/* bInheritHandles */ TRUE,
/* dwCreationFlags */ DETACHED_PROCESS | CREATE_NEW_PROCESS_GROUP,
/* lpEnvironment */ NULL,
/* lpCurrentDirectory */ NULL,
/* lpStartupInfo */ &startupInfo,
/* lpProcessInformation */ &processInfo);

if (!ok) {
pdie(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
Expand Down Expand Up @@ -679,21 +699,20 @@ void ExecuteProgram(
pdie(255, "Error %u while setting up job\n", GetLastError());
}

bool success = CreateProcessA(
NULL, // _In_opt_ LPCTSTR lpApplicationName,
// _Inout_opt_ LPTSTR lpCommandLine,
cmdline.cmdline,
NULL, // _In_opt_ LPSECURITY_ATTRIBUTES lpProcessAttributes,
NULL, // _In_opt_ LPSECURITY_ATTRIBUTES lpThreadAttributes,
true, // _In_ BOOL bInheritHandles,
// _In_ DWORD dwCreationFlags,
CREATE_NEW_PROCESS_GROUP // So that Ctrl-Break does not affect it
BOOL success = CreateProcessA(
/* lpApplicationName */ NULL,
/* lpCommandLine */ cmdline.cmdline,
/* lpProcessAttributes */ NULL,
/* lpThreadAttributes */ NULL,
/* bInheritHandles */ TRUE,
/* dwCreationFlags */
CREATE_NEW_PROCESS_GROUP // So that Ctrl-Break does not affect it
| CREATE_BREAKAWAY_FROM_JOB // We'll put it in a new job
| CREATE_SUSPENDED, // So that it doesn't start a new job itself
NULL, // _In_opt_ LPVOID lpEnvironment,
NULL, // _In_opt_ LPCTSTR lpCurrentDirectory,
&startupInfo, // _In_ LPSTARTUPINFO lpStartupInfo,
&processInfo); // _Out_ LPPROCESS_INFORMATION lpProcessInformation
/* lpEnvironment */ NULL,
/* lpCurrentDirectory */ NULL,
/* lpStartupInfo */ &startupInfo,
/* lpProcessInformation */ &processInfo);

if (!success) {
pdie(255, "ExecuteProgram/CreateProcess: error %u executing: %s\n",
Expand Down Expand Up @@ -801,13 +820,15 @@ typedef struct {

HANDLE OpenDirectory(const string& path, bool readWrite) {
HANDLE result = ::CreateFileA(
path.c_str(),
readWrite ? (GENERIC_READ | GENERIC_WRITE) : GENERIC_READ,
0,
NULL,
OPEN_EXISTING,
FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS,
NULL);
/* lpFileName */ path.c_str(),
/* dwDesiredAccess */ readWrite ? (GENERIC_READ | GENERIC_WRITE)
: GENERIC_READ,
/* dwShareMode */ 0,
/* lpSecurityAttributes */ NULL,
/* dwCreationDisposition */ OPEN_EXISTING,
/* dwFlagsAndAttributes */ FILE_FLAG_OPEN_REPARSE_POINT |
FILE_FLAG_BACKUP_SEMANTICS,
/* hTemplateFile */ NULL);
if (result == INVALID_HANDLE_VALUE) {
PrintError("CreateFile(" + path + ")");
}
Expand Down

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