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 part of wimlib, a library for working with WIM files.
11 * wimlib is free software; you can redistribute it and/or modify it under the
12 * terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 3 of the License, or (at your option)
16 * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
17 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
18 * A PARTICULAR PURPOSE. See the GNU General Public License for more
21 * You should have received a copy of the GNU General Public License
22 * along with wimlib; if not, see http://www.gnu.org/licenses/.
33 #include <io.h> /* for _get_osfhandle() */
36 #include "wimlib/win32_common.h"
38 #include "wimlib/assert.h"
39 #include "wimlib/glob.h"
40 #include "wimlib/error.h"
41 #include "wimlib/util.h"
43 /* Replacement for POSIX fsync() */
49 h = (HANDLE)_get_osfhandle(fd);
50 if (h == INVALID_HANDLE_VALUE)
52 if (!FlushFileBuffers(h))
56 set_errno_from_GetLastError();
61 /* Use the Win32 API to get the number of processors. */
63 win32_get_number_of_processors(void)
66 GetSystemInfo(&sysinfo);
67 return sysinfo.dwNumberOfProcessors;
70 /* Use the Win32 API to get the amount of available memory. */
72 win32_get_avail_memory(void)
74 MEMORYSTATUSEX status = {
75 .dwLength = sizeof(status),
77 GlobalMemoryStatusEx(&status);
78 return status.ullTotalPhys;
81 /* Replacement for POSIX-2008 realpath(). Warning: partial functionality only
82 * (resolved_path must be NULL). Also I highly doubt that GetFullPathName
83 * really does the right thing under all circumstances. */
85 realpath(const wchar_t *path, wchar_t *resolved_path)
89 wimlib_assert(resolved_path == NULL);
91 ret = GetFullPathNameW(path, 0, NULL, NULL);
97 resolved_path = MALLOC(ret * sizeof(wchar_t));
100 ret = GetFullPathNameW(path, ret, resolved_path, NULL);
102 err = GetLastError();
104 resolved_path = NULL;
109 set_errno_from_win32_error(err);
111 return resolved_path;
114 /* A quick hack to get reasonable rename() semantics on Windows, in particular
115 * deleting the destination file instead of failing with ERROR_FILE_EXISTS and
116 * working around any processes that may have the destination file open.
118 * Note: This is intended to be called when overwriting a regular file with an
119 * updated copy and is *not* a fully POSIX compliant rename(). For that you may
120 * wish to take a look at Cygwin's implementation, but be prepared...
122 * Return 0 on success, -1 on regular error, or 1 if the destination file was
123 * deleted but the source could not be renamed and therefore should not be
127 win32_rename_replacement(const wchar_t *srcpath, const wchar_t *dstpath)
131 /* Normally, MoveFileExW() with the MOVEFILE_REPLACE_EXISTING flag does
134 if (MoveFileExW(srcpath, dstpath, MOVEFILE_REPLACE_EXISTING))
137 /* MoveFileExW() failed. One way this can happen is if any process has
138 * the destination file open, in which case ERROR_ACCESS_DENIED is
139 * produced. This can commonly happen if there is a backup or antivirus
140 * program monitoring or scanning the files. This behavior is very
141 * different from the behavior of POSIX rename(), which simply unlinks
142 * the destination file and allows other processes to keep it open! */
144 if (GetLastError() != ERROR_ACCESS_DENIED)
147 /* We can work around the above-mentioned problem by renaming the
148 * destination file to yet another temporary file, then "deleting" it,
149 * which on Windows will in fact not actually delete it immediately but
150 * rather mark it for deletion when the last handle to it is closed. */
152 static const wchar_t orig_suffix[5] = L".orig";
153 const size_t num_rand_chars = 9;
156 size_t dstlen = wcslen(dstpath);
158 tmpname = alloca(sizeof(wchar_t) *
159 (dstlen + ARRAY_LEN(orig_suffix) + num_rand_chars + 1));
161 p = wmempcpy(p, dstpath, dstlen);
162 p = wmempcpy(p, orig_suffix, ARRAY_LEN(orig_suffix));
163 randomize_char_array_with_alnum(p, num_rand_chars);
168 if (!MoveFile(dstpath, tmpname))
171 if (!DeleteFile(tmpname)) {
172 set_errno_from_GetLastError();
173 WARNING_WITH_ERRNO("Failed to delete original file "
174 "(moved to \"%ls\")", tmpname);
177 if (!MoveFile(srcpath, dstpath)) {
178 set_errno_from_GetLastError();
179 WARNING_WITH_ERRNO("Atomic semantics not respected in "
180 "failed rename() (new file is at \"%ls\")",
188 set_errno_from_GetLastError();
192 /* This really could be replaced with _wcserror_s, but this doesn't seem to
193 * actually be available in MSVCRT.DLL on Windows XP (perhaps it's statically
194 * linked in by Visual Studio...?). */
196 win32_strerror_r_replacement(int errnum, wchar_t *buf, size_t buflen)
198 static pthread_mutex_t strerror_lock = PTHREAD_MUTEX_INITIALIZER;
200 pthread_mutex_lock(&strerror_lock);
201 mbstowcs(buf, strerror(errnum), buflen);
202 buf[buflen - 1] = '\0';
203 pthread_mutex_unlock(&strerror_lock);
208 do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
212 LARGE_INTEGER orig_offset;
213 DWORD bytes_read_or_written;
214 LARGE_INTEGER relative_offset;
215 OVERLAPPED overlapped;
218 h = (HANDLE)_get_osfhandle(fd);
219 if (h == INVALID_HANDLE_VALUE)
222 if (GetFileType(h) == FILE_TYPE_PIPE) {
227 /* Get original position */
228 relative_offset.QuadPart = 0;
229 if (!SetFilePointerEx(h, relative_offset, &orig_offset, FILE_CURRENT))
232 memset(&overlapped, 0, sizeof(overlapped));
233 overlapped.Offset = offset;
234 overlapped.OffsetHigh = offset >> 32;
236 /* Do the read or write at the specified offset */
238 bret = WriteFile(h, buf, count, &bytes_read_or_written, &overlapped);
240 bret = ReadFile(h, buf, count, &bytes_read_or_written, &overlapped);
244 /* Restore the original position */
245 if (!SetFilePointerEx(h, orig_offset, NULL, FILE_BEGIN))
248 return bytes_read_or_written;
250 set_errno_from_GetLastError();
255 /* Dumb Windows implementation of pread(). It temporarily changes the file
256 * offset, so it is not safe to use with readers/writers on the same file
259 pread(int fd, void *buf, size_t count, off_t offset)
261 return do_pread_or_pwrite(fd, buf, count, offset, false);
264 /* Dumb Windows implementation of pwrite(). It temporarily changes the file
265 * offset, so it is not safe to use with readers/writers on the same file
268 pwrite(int fd, const void *buf, size_t count, off_t offset)
270 return do_pread_or_pwrite(fd, (void*)buf, count, offset, true);
273 /* Replacement for glob() in Windows native builds that operates on wide
276 win32_wglob(const wchar_t *pattern, int flags,
277 int (*errfunc)(const wchar_t *epath, int eerrno),
280 WIN32_FIND_DATAW dat;
287 const wchar_t *backslash, *end_slash;
290 backslash = wcsrchr(pattern, L'\\');
291 end_slash = wcsrchr(pattern, L'/');
293 if (backslash > end_slash)
294 end_slash = backslash;
297 prefix_len = end_slash - pattern + 1;
301 /* This function does not support all functionality of the POSIX glob(),
302 * so make sure the parameters are consistent with supported
304 wimlib_assert(errfunc == NULL);
305 wimlib_assert((flags & GLOB_ERR) == GLOB_ERR);
306 wimlib_assert((flags & ~(GLOB_NOSORT | GLOB_ERR)) == 0);
308 hFind = FindFirstFileW(pattern, &dat);
309 if (hFind == INVALID_HANDLE_VALUE) {
310 err = GetLastError();
311 if (err == ERROR_FILE_NOT_FOUND) {
315 set_errno_from_win32_error(err);
320 pglob->gl_pathv = NULL;
324 if (pglob->gl_pathc == nspaces) {
328 new_nspaces = nspaces * 2 + 1;
329 pathv = REALLOC(pglob->gl_pathv,
330 new_nspaces * sizeof(pglob->gl_pathv[0]));
333 pglob->gl_pathv = pathv;
334 nspaces = new_nspaces;
336 size_t filename_len = wcslen(dat.cFileName);
337 size_t len_needed = prefix_len + filename_len;
339 path = MALLOC((len_needed + 1) * sizeof(wchar_t));
343 wmemcpy(path, pattern, prefix_len);
344 wmemcpy(path + prefix_len, dat.cFileName, filename_len + 1);
345 pglob->gl_pathv[pglob->gl_pathc++] = path;
346 } while (FindNextFileW(hFind, &dat));
347 err = GetLastError();
349 if (err != ERROR_NO_MORE_FILES) {
350 set_errno_from_win32_error(err);
368 globfree(glob_t *pglob)
371 for (i = 0; i < pglob->gl_pathc; i++)
372 FREE(pglob->gl_pathv[i]);
373 FREE(pglob->gl_pathv);
376 /* Replacement for fopen(path, "a") that doesn't prevent other processes from
377 * reading the file */
379 win32_open_logfile(const wchar_t *path)
385 h = CreateFile(path, FILE_APPEND_DATA, FILE_SHARE_VALID_FLAGS,
386 NULL, OPEN_ALWAYS, 0, NULL);
387 if (h == INVALID_HANDLE_VALUE)
390 fd = _open_osfhandle((intptr_t)h, O_APPEND);
396 fp = fdopen(fd, "a");
405 #endif /* __WIN32__ */