2 * win32_replacements.c - Replacements for various functions not available on
3 * Windows, such as fsync().
7 * Copyright (C) 2013 Eric Biggers
9 * This file is free software; you can redistribute it and/or modify it under
10 * the terms of the GNU Lesser General Public License as published by the Free
11 * Software Foundation; either version 3 of the License, or (at your option) any
14 * This file is distributed in the hope that it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
19 * You should have received a copy of the GNU Lesser General Public License
20 * along with this file; if not, see http://www.gnu.org/licenses/.
31 #include <io.h> /* for _get_osfhandle() */
34 #include "wimlib/win32_common.h"
36 #include "wimlib/assert.h"
37 #include "wimlib/glob.h"
38 #include "wimlib/error.h"
39 #include "wimlib/util.h"
41 /* Replacement for POSIX fsync() */
47 h = (HANDLE)_get_osfhandle(fd);
48 if (h == INVALID_HANDLE_VALUE)
50 if (!FlushFileBuffers(h))
54 set_errno_from_GetLastError();
59 /* Use the Win32 API to get the number of processors. */
61 win32_get_number_of_processors(void)
64 GetSystemInfo(&sysinfo);
65 return sysinfo.dwNumberOfProcessors;
68 /* Use the Win32 API to get the amount of available memory. */
70 win32_get_avail_memory(void)
72 MEMORYSTATUSEX status = {
73 .dwLength = sizeof(status),
75 GlobalMemoryStatusEx(&status);
76 return (u64)min(status.ullTotalPhys, status.ullTotalVirtual) * 85 / 100;
79 /* Replacement for POSIX-2008 realpath(). Warning: partial functionality only
80 * (resolved_path must be NULL). Also I highly doubt that GetFullPathName
81 * really does the right thing under all circumstances. */
83 realpath(const wchar_t *path, wchar_t *resolved_path)
87 wimlib_assert(resolved_path == NULL);
89 ret = GetFullPathNameW(path, 0, NULL, NULL);
95 resolved_path = MALLOC(ret * sizeof(wchar_t));
98 ret = GetFullPathNameW(path, ret, resolved_path, NULL);
100 err = GetLastError();
102 resolved_path = NULL;
107 set_errno_from_win32_error(err);
109 return resolved_path;
112 /* A quick hack to get reasonable rename() semantics on Windows, in particular
113 * deleting the destination file instead of failing with ERROR_FILE_EXISTS and
114 * working around any processes that may have the destination file open.
116 * Note: This is intended to be called when overwriting a regular file with an
117 * updated copy and is *not* a fully POSIX compliant rename(). For that you may
118 * wish to take a look at Cygwin's implementation, but be prepared...
120 * Return 0 on success, -1 on regular error, or 1 if the destination file was
121 * deleted but the source could not be renamed and therefore should not be
125 win32_rename_replacement(const wchar_t *srcpath, const wchar_t *dstpath)
129 /* Normally, MoveFileExW() with the MOVEFILE_REPLACE_EXISTING flag does
132 if (MoveFileExW(srcpath, dstpath, MOVEFILE_REPLACE_EXISTING))
135 /* MoveFileExW() failed. One way this can happen is if any process has
136 * the destination file open, in which case ERROR_ACCESS_DENIED is
137 * produced. This can commonly happen if there is a backup or antivirus
138 * program monitoring or scanning the files. This behavior is very
139 * different from the behavior of POSIX rename(), which simply unlinks
140 * the destination file and allows other processes to keep it open! */
142 if (GetLastError() != ERROR_ACCESS_DENIED)
145 /* We can work around the above-mentioned problem by renaming the
146 * destination file to yet another temporary file, then "deleting" it,
147 * which on Windows will in fact not actually delete it immediately but
148 * rather mark it for deletion when the last handle to it is closed. */
150 static const wchar_t orig_suffix[5] = L".orig";
151 const size_t num_rand_chars = 9;
154 size_t dstlen = wcslen(dstpath);
156 tmpname = alloca(sizeof(wchar_t) *
157 (dstlen + ARRAY_LEN(orig_suffix) + num_rand_chars + 1));
159 p = wmempcpy(p, dstpath, dstlen);
160 p = wmempcpy(p, orig_suffix, ARRAY_LEN(orig_suffix));
161 randomize_char_array_with_alnum(p, num_rand_chars);
166 if (!MoveFile(dstpath, tmpname))
169 if (!DeleteFile(tmpname)) {
170 set_errno_from_GetLastError();
171 WARNING_WITH_ERRNO("Failed to delete original file "
172 "(moved to \"%ls\")", tmpname);
175 if (!MoveFile(srcpath, dstpath)) {
176 set_errno_from_GetLastError();
177 WARNING_WITH_ERRNO("Atomic semantics not respected in "
178 "failed rename() (new file is at \"%ls\")",
186 set_errno_from_GetLastError();
190 /* This really could be replaced with _wcserror_s, but this doesn't seem to
191 * actually be available in MSVCRT.DLL on Windows XP (perhaps it's statically
192 * linked in by Visual Studio...?). */
194 win32_strerror_r_replacement(int errnum, wchar_t *buf, size_t buflen)
196 static pthread_mutex_t strerror_lock = PTHREAD_MUTEX_INITIALIZER;
198 pthread_mutex_lock(&strerror_lock);
199 mbstowcs(buf, strerror(errnum), buflen);
200 buf[buflen - 1] = '\0';
201 pthread_mutex_unlock(&strerror_lock);
206 do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
210 LARGE_INTEGER orig_offset;
211 DWORD bytes_read_or_written;
212 LARGE_INTEGER relative_offset;
213 OVERLAPPED overlapped;
216 h = (HANDLE)_get_osfhandle(fd);
217 if (h == INVALID_HANDLE_VALUE)
220 if (GetFileType(h) == FILE_TYPE_PIPE) {
225 /* Get original position */
226 relative_offset.QuadPart = 0;
227 if (!SetFilePointerEx(h, relative_offset, &orig_offset, FILE_CURRENT))
230 memset(&overlapped, 0, sizeof(overlapped));
231 overlapped.Offset = offset;
232 overlapped.OffsetHigh = offset >> 32;
234 /* Do the read or write at the specified offset */
236 bret = WriteFile(h, buf, count, &bytes_read_or_written, &overlapped);
238 bret = ReadFile(h, buf, count, &bytes_read_or_written, &overlapped);
242 /* Restore the original position */
243 if (!SetFilePointerEx(h, orig_offset, NULL, FILE_BEGIN))
246 return bytes_read_or_written;
248 set_errno_from_GetLastError();
253 /* Dumb Windows implementation of pread(). It temporarily changes the file
254 * offset, so it is not safe to use with readers/writers on the same file
257 pread(int fd, void *buf, size_t count, off_t offset)
259 return do_pread_or_pwrite(fd, buf, count, offset, false);
262 /* Dumb Windows implementation of pwrite(). It temporarily changes the file
263 * offset, so it is not safe to use with readers/writers on the same file
266 pwrite(int fd, const void *buf, size_t count, off_t offset)
268 return do_pread_or_pwrite(fd, (void*)buf, count, offset, true);
271 /* Replacement for glob() in Windows native builds that operates on wide
274 win32_wglob(const wchar_t *pattern, int flags,
275 int (*errfunc)(const wchar_t *epath, int eerrno),
278 WIN32_FIND_DATAW dat;
285 const wchar_t *backslash, *end_slash;
288 backslash = wcsrchr(pattern, L'\\');
289 end_slash = wcsrchr(pattern, L'/');
291 if (backslash > end_slash)
292 end_slash = backslash;
295 prefix_len = end_slash - pattern + 1;
299 /* This function does not support all functionality of the POSIX glob(),
300 * so make sure the parameters are consistent with supported
302 wimlib_assert(errfunc == NULL);
303 wimlib_assert((flags & GLOB_ERR) == GLOB_ERR);
304 wimlib_assert((flags & ~(GLOB_NOSORT | GLOB_ERR)) == 0);
306 hFind = FindFirstFileW(pattern, &dat);
307 if (hFind == INVALID_HANDLE_VALUE) {
308 err = GetLastError();
309 if (err == ERROR_FILE_NOT_FOUND) {
313 set_errno_from_win32_error(err);
318 pglob->gl_pathv = NULL;
322 if (pglob->gl_pathc == nspaces) {
326 new_nspaces = nspaces * 2 + 1;
327 pathv = REALLOC(pglob->gl_pathv,
328 new_nspaces * sizeof(pglob->gl_pathv[0]));
331 pglob->gl_pathv = pathv;
332 nspaces = new_nspaces;
334 size_t filename_len = wcslen(dat.cFileName);
335 size_t len_needed = prefix_len + filename_len;
337 path = MALLOC((len_needed + 1) * sizeof(wchar_t));
341 wmemcpy(path, pattern, prefix_len);
342 wmemcpy(path + prefix_len, dat.cFileName, filename_len + 1);
343 pglob->gl_pathv[pglob->gl_pathc++] = path;
344 } while (FindNextFileW(hFind, &dat));
345 err = GetLastError();
347 if (err != ERROR_NO_MORE_FILES) {
348 set_errno_from_win32_error(err);
366 globfree(glob_t *pglob)
369 for (i = 0; i < pglob->gl_pathc; i++)
370 FREE(pglob->gl_pathv[i]);
371 FREE(pglob->gl_pathv);
374 /* Replacement for fopen(path, "a") that doesn't prevent other processes from
375 * reading the file */
377 win32_open_logfile(const wchar_t *path)
383 h = CreateFile(path, FILE_APPEND_DATA, FILE_SHARE_VALID_FLAGS,
384 NULL, OPEN_ALWAYS, 0, NULL);
385 if (h == INVALID_HANDLE_VALUE)
388 fd = _open_osfhandle((intptr_t)h, O_APPEND);
394 fp = fdopen(fd, "a");
403 #endif /* __WIN32__ */