From 5f28e2e37520af1fd8a3a4ac4298c4a46ef92b0d Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Mon, 11 May 2015 19:54:23 +0200 Subject: [PATCH 01/19] strbuf_readlink: don't call readlink twice if hint is the exact link size strbuf_readlink() calls readlink() twice if the hint argument specifies the exact size of the link target (e.g. by passing stat.st_size as returned by lstat()). This is necessary because 'readlink(..., hint) == hint' could mean that the buffer was too small. Use hint + 1 as buffer size to prevent this. Signed-off-by: Karsten Blees --- strbuf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/strbuf.c b/strbuf.c index d30f916858..ac1173b1d3 100644 --- a/strbuf.c +++ b/strbuf.c @@ -552,12 +552,12 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint) while (hint < STRBUF_MAXLINK) { ssize_t len; - strbuf_grow(sb, hint); - len = readlink(path, sb->buf, hint); + strbuf_grow(sb, hint + 1); + len = readlink(path, sb->buf, hint + 1); if (len < 0) { if (errno != ERANGE) break; - } else if (len < hint) { + } else if (len <= hint) { strbuf_setlen(sb, len); return 0; } From a846050b206db87da676d0e600c4ae7ee864492a Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Mon, 11 May 2015 22:15:40 +0200 Subject: [PATCH 02/19] strbuf_readlink: support link targets that exceed PATH_MAX strbuf_readlink() refuses to read link targets that exceed PATH_MAX (even if a sufficient size was specified by the caller). As some platforms support longer paths, remove this restriction (similar to strbuf_getcwd()). Signed-off-by: Karsten Blees --- strbuf.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/strbuf.c b/strbuf.c index ac1173b1d3..5ed95a0a17 100644 --- a/strbuf.c +++ b/strbuf.c @@ -540,8 +540,6 @@ ssize_t strbuf_write(struct strbuf *sb, FILE *f) } -#define STRBUF_MAXLINK (2*PATH_MAX) - int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint) { size_t oldalloc = sb->alloc; @@ -549,7 +547,7 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint) if (hint < 32) hint = 32; - while (hint < STRBUF_MAXLINK) { + for (;;) { ssize_t len; strbuf_grow(sb, hint + 1); From 35d7b9afe1080f0397d5e5c5cfbf7ee133eeac42 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Mon, 11 May 2015 19:58:14 +0200 Subject: [PATCH 03/19] lockfile.c: use is_dir_sep() instead of hardcoded '/' checks Signed-off-by: Karsten Blees --- lockfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lockfile.c b/lockfile.c index 8e8ab4f29f..3704a603f6 100644 --- a/lockfile.c +++ b/lockfile.c @@ -17,14 +17,14 @@ static void trim_last_path_component(struct strbuf *path) int i = path->len; /* back up past trailing slashes, if any */ - while (i && path->buf[i - 1] == '/') + while (i && is_dir_sep(path->buf[i - 1])) i--; /* * then go backwards until a slash, or the beginning of the * string */ - while (i && path->buf[i - 1] != '/') + while (i && !is_dir_sep(path->buf[i - 1])) i--; strbuf_setlen(path, i); From fa7b16e4de9ff26e2e15dda1204fb7b4ebbe982f Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Tue, 12 May 2015 11:09:01 +0200 Subject: [PATCH 04/19] Win32: don't call GetFileAttributes twice in mingw_lstat() GetFileAttributes cannot handle paths with trailing dir separator. The current [l]stat implementation calls GetFileAttributes twice if the path has trailing slashes (first with the original path passed to [l]stat, and and a second time with a path copy with trailing '/' removed). With Unicode conversion, we get the length of the path for free and also have a (wide char) buffer that can be modified. Remove trailing directory separators before calling the Win32 API. Signed-off-by: Karsten Blees --- compat/mingw.c | 48 ++++++++++++------------------------------------ 1 file changed, 12 insertions(+), 36 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 7cc1cd72fc..414f74415e 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -730,9 +730,18 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf) { WIN32_FILE_ATTRIBUTE_DATA fdata; wchar_t wfilename[MAX_LONG_PATH]; - if (xutftowcs_long_path(wfilename, file_name) < 0) + int wlen = xutftowcs_long_path(wfilename, file_name); + if (wlen < 0) return -1; + /* strip trailing '/', or GetFileAttributes will fail */ + while (wlen && is_dir_sep(wfilename[wlen - 1])) + wfilename[--wlen] = 0; + if (!wlen) { + errno = ENOENT; + return -1; + } + if (GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata)) { buf->st_ino = 0; buf->st_gid = 0; @@ -792,39 +801,6 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf) return -1; } -/* We provide our own lstat/fstat functions, since the provided - * lstat/fstat functions are so slow. These stat functions are - * tailored for Git's usage (read: fast), and are not meant to be - * complete. Note that Git stat()s are redirected to mingw_lstat() - * too, since Windows doesn't really handle symlinks that well. - */ -static int do_stat_internal(int follow, const char *file_name, struct stat *buf) -{ - int namelen; - char alt_name[MAX_LONG_PATH]; - - if (!do_lstat(follow, file_name, buf)) - return 0; - - /* if file_name ended in a '/', Windows returned ENOENT; - * try again without trailing slashes - */ - if (errno != ENOENT) - return -1; - - namelen = strlen(file_name); - if (namelen && file_name[namelen-1] != '/') - return -1; - while (namelen && file_name[namelen-1] == '/') - --namelen; - if (!namelen || namelen >= MAX_LONG_PATH) - return -1; - - memcpy(alt_name, file_name, namelen); - alt_name[namelen] = 0; - return do_lstat(follow, alt_name, buf); -} - int (*lstat)(const char *file_name, struct stat *buf) = mingw_lstat; static int get_file_info_by_handle(HANDLE hnd, struct stat *buf) @@ -852,11 +828,11 @@ static int get_file_info_by_handle(HANDLE hnd, struct stat *buf) int mingw_lstat(const char *file_name, struct stat *buf) { - return do_stat_internal(0, file_name, buf); + return do_lstat(0, file_name, buf); } int mingw_stat(const char *file_name, struct stat *buf) { - return do_stat_internal(1, file_name, buf); + return do_lstat(1, file_name, buf); } int mingw_fstat(int fd, struct stat *buf) From 65a8b7d8e5b69f12f5b437baea6f9fa29cb601ac Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sat, 16 May 2015 01:18:14 +0200 Subject: [PATCH 05/19] Win32: implement stat() with symlink support With respect to symlinks, the current stat() implementation is almost the same as lstat(): except for the file type (st_mode & S_IFMT), it returns information about the link rather than the target. Implement stat by opening the file with as little permissions as possible and calling GetFileInformationByHandle on it. This way, all link resoltion is handled by the Windows file system layer. If symlinks are disabled, use lstat() as before, but fail with ELOOP if a symlink would have to be resolved. Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- compat/mingw.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/compat/mingw.c b/compat/mingw.c index 414f74415e..29185f5db5 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -830,9 +830,26 @@ int mingw_lstat(const char *file_name, struct stat *buf) { return do_lstat(0, file_name, buf); } + int mingw_stat(const char *file_name, struct stat *buf) { - return do_lstat(1, file_name, buf); + wchar_t wfile_name[MAX_LONG_PATH]; + HANDLE hnd; + int result; + + /* open the file and let Windows resolve the links */ + if (xutftowcs_long_path(wfile_name, file_name) < 0) + return -1; + hnd = CreateFileW(wfile_name, 0, + FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, + OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL); + if (hnd == INVALID_HANDLE_VALUE) { + errno = err_win_to_posix(GetLastError()); + return -1; + } + result = get_file_info_by_handle(hnd, buf); + CloseHandle(hnd); + return result; } int mingw_fstat(int fd, struct stat *buf) From 222076fc83b9023d27dfbdf50a36d5fae697dc5e Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Tue, 12 May 2015 00:58:39 +0200 Subject: [PATCH 06/19] Win32: remove separate do_lstat() function With the new mingw_stat() implementation, do_lstat() is only called from mingw_lstat() (with follow == 0). Remove the extra function and the old mingw_stat()-specific (follow == 1) logic. Signed-off-by: Karsten Blees --- compat/mingw.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 29185f5db5..78c42ce3db 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -719,14 +719,7 @@ static int has_valid_directory_prefix(wchar_t *wfilename) return 1; } -/* We keep the do_lstat code in a separate function to avoid recursion. - * When a path ends with a slash, the stat will fail with ENOENT. In - * this case, we strip the trailing slashes and stat again. - * - * If follow is true then act like stat() and report on the link - * target. Otherwise report on the link itself. - */ -static int do_lstat(int follow, const char *file_name, struct stat *buf) +int mingw_lstat(const char *file_name, struct stat *buf) { WIN32_FILE_ATTRIBUTE_DATA fdata; wchar_t wfilename[MAX_LONG_PATH]; @@ -760,13 +753,7 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf) if (handle != INVALID_HANDLE_VALUE) { if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) && (findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) { - if (follow) { - char buffer[MAXIMUM_REPARSE_DATA_BUFFER_SIZE]; - buf->st_size = readlink(file_name, buffer, MAXIMUM_REPARSE_DATA_BUFFER_SIZE); - } else { - buf->st_mode = S_IFLNK; - } - buf->st_mode |= S_IREAD; + buf->st_mode = S_IFLNK | S_IREAD; if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY)) buf->st_mode |= S_IWRITE; } @@ -826,11 +813,6 @@ static int get_file_info_by_handle(HANDLE hnd, struct stat *buf) return 0; } -int mingw_lstat(const char *file_name, struct stat *buf) -{ - return do_lstat(0, file_name, buf); -} - int mingw_stat(const char *file_name, struct stat *buf) { wchar_t wfile_name[MAX_LONG_PATH]; From ab01a83913a1fee0294c75cef91c9710bc8b7d9d Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 00:17:56 +0200 Subject: [PATCH 07/19] Win32: let mingw_lstat() error early upon problems with reparse points When obtaining lstat information for reparse points, we need to call FindFirstFile() in addition to GetFileInformationEx() to obtain the type of the reparse point (symlink, mount point etc.). However, currently there is no error handling whatsoever if FindFirstFile() fails. Call FindFirstFile() before modifying the stat *buf output parameter and error out if the call fails. Note: The FindFirstFile() return value includes all the data that we get from GetFileAttributesEx(), so we could replace GetFileAttributesEx() with FindFirstFile(). We don't do that because GetFileAttributesEx() is about twice as fast for single files. I.e. we only pay the extra cost of calling FindFirstFile() in the rare case that we encounter a reparse point. Note: The indentation of the remaining reparse point code will be fixed in the next patch. Signed-off-by: Karsten Blees --- compat/mingw.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 78c42ce3db..d58252425e 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -722,6 +722,7 @@ static int has_valid_directory_prefix(wchar_t *wfilename) int mingw_lstat(const char *file_name, struct stat *buf) { WIN32_FILE_ATTRIBUTE_DATA fdata; + WIN32_FIND_DATAW findbuf = { 0 }; wchar_t wfilename[MAX_LONG_PATH]; int wlen = xutftowcs_long_path(wfilename, file_name); if (wlen < 0) @@ -736,6 +737,13 @@ int mingw_lstat(const char *file_name, struct stat *buf) } if (GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata)) { + /* for reparse points, use FindFirstFile to get the reparse tag */ + if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) { + HANDLE handle = FindFirstFileW(wfilename, &findbuf); + if (handle == INVALID_HANDLE_VALUE) + goto error; + FindClose(handle); + } buf->st_ino = 0; buf->st_gid = 0; buf->st_uid = 0; @@ -748,20 +756,16 @@ int mingw_lstat(const char *file_name, struct stat *buf) filetime_to_timespec(&(fdata.ftLastWriteTime), &(buf->st_mtim)); filetime_to_timespec(&(fdata.ftCreationTime), &(buf->st_ctim)); if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) { - WIN32_FIND_DATAW findbuf; - HANDLE handle = FindFirstFileW(wfilename, &findbuf); - if (handle != INVALID_HANDLE_VALUE) { if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) && (findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) { buf->st_mode = S_IFLNK | S_IREAD; if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY)) buf->st_mode |= S_IWRITE; } - FindClose(handle); - } } return 0; } +error: switch (GetLastError()) { case ERROR_ACCESS_DENIED: case ERROR_SHARING_VIOLATION: From 1c21066608fbfa8a42c2c7c2238db86cc4560294 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Tue, 10 Jan 2017 23:21:56 +0100 Subject: [PATCH 08/19] Win32: teach fscache and dirent about symlinks Move S_IFLNK detection to file_attr_to_st_mode() and reuse it in fscache. Implement DT_LNK detection in dirent.c and the fscache readdir version. Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- compat/mingw.c | 13 +++---------- compat/win32.h | 6 ++++-- compat/win32/dirent.c | 5 ++++- compat/win32/fscache.c | 8 +++++--- 4 files changed, 16 insertions(+), 16 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index d58252425e..e9625343e9 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -748,21 +748,14 @@ int mingw_lstat(const char *file_name, struct stat *buf) buf->st_gid = 0; buf->st_uid = 0; buf->st_nlink = 1; - buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes); + buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes, + findbuf.dwReserved0); buf->st_size = fdata.nFileSizeLow | (((off_t)fdata.nFileSizeHigh)<<32); buf->st_dev = buf->st_rdev = 0; /* not used by Git */ filetime_to_timespec(&(fdata.ftLastAccessTime), &(buf->st_atim)); filetime_to_timespec(&(fdata.ftLastWriteTime), &(buf->st_mtim)); filetime_to_timespec(&(fdata.ftCreationTime), &(buf->st_ctim)); - if (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) { - if ((findbuf.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) && - (findbuf.dwReserved0 == IO_REPARSE_TAG_SYMLINK)) { - buf->st_mode = S_IFLNK | S_IREAD; - if (!(findbuf.dwFileAttributes & FILE_ATTRIBUTE_READONLY)) - buf->st_mode |= S_IWRITE; - } - } return 0; } error: @@ -807,7 +800,7 @@ static int get_file_info_by_handle(HANDLE hnd, struct stat *buf) buf->st_gid = 0; buf->st_uid = 0; buf->st_nlink = 1; - buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes); + buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes, 0); buf->st_size = fdata.nFileSizeLow | (((off_t)fdata.nFileSizeHigh)<<32); buf->st_dev = buf->st_rdev = 0; /* not used by Git */ diff --git a/compat/win32.h b/compat/win32.h index a97e880757..671bcc81f9 100644 --- a/compat/win32.h +++ b/compat/win32.h @@ -6,10 +6,12 @@ #include #endif -static inline int file_attr_to_st_mode (DWORD attr) +static inline int file_attr_to_st_mode (DWORD attr, DWORD tag) { int fMode = S_IREAD; - if (attr & FILE_ATTRIBUTE_DIRECTORY) + if ((attr & FILE_ATTRIBUTE_REPARSE_POINT) && tag == IO_REPARSE_TAG_SYMLINK) + fMode |= S_IFLNK; + else if (attr & FILE_ATTRIBUTE_DIRECTORY) fMode |= S_IFDIR; else fMode |= S_IFREG; diff --git a/compat/win32/dirent.c b/compat/win32/dirent.c index b3bd8d7af7..8c654d722b 100644 --- a/compat/win32/dirent.c +++ b/compat/win32/dirent.c @@ -16,7 +16,10 @@ static inline void finddata2dirent(struct dirent *ent, WIN32_FIND_DATAW *fdata) xwcstoutf(ent->d_name, fdata->cFileName, MAX_PATH * 3); /* Set file type, based on WIN32_FIND_DATA */ - if (fdata->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) + if ((fdata->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) + && fdata->dwReserved0 == IO_REPARSE_TAG_SYMLINK) + ent->d_type = DT_LNK; + else if (fdata->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ent->d_type = DT_DIR; else ent->d_type = DT_REG; diff --git a/compat/win32/fscache.c b/compat/win32/fscache.c index 3341c68562..e60112e5ab 100644 --- a/compat/win32/fscache.c +++ b/compat/win32/fscache.c @@ -185,8 +185,9 @@ static struct fsentry *fseentry_create_entry(struct fscache *cache, struct fsent fdata->FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT ? fdata->EaSize : 0; - fse->st_mode = file_attr_to_st_mode(fdata->FileAttributes); - fse->u.s.st_size = fdata->EndOfFile.LowPart | (((off_t)fdata->EndOfFile.HighPart) << 32); + fse->st_mode = file_attr_to_st_mode(fdata->FileAttributes, fdata->EaSize); + fse->u.s.st_size = S_ISLNK(fse->st_mode) ? MAX_LONG_PATH : + fdata->EndOfFile.LowPart | (((off_t)fdata->EndOfFile.HighPart) << 32); filetime_to_timespec((FILETIME *)&(fdata->LastAccessTime), &(fse->u.s.st_atim)); filetime_to_timespec((FILETIME *)&(fdata->LastWriteTime), &(fse->u.s.st_mtim)); filetime_to_timespec((FILETIME *)&(fdata->CreationTime), &(fse->u.s.st_ctim)); @@ -619,7 +620,8 @@ static struct dirent *fscache_readdir(DIR *base_dir) if (!next) return NULL; dir->pfsentry = next; - dir->dirent.d_type = S_ISDIR(next->st_mode) ? DT_DIR : DT_REG; + dir->dirent.d_type = S_ISREG(next->st_mode) ? DT_REG : + S_ISDIR(next->st_mode) ? DT_DIR : DT_LNK; dir->dirent.d_name = (char*) next->name; return &(dir->dirent); } From df6c40120214aaa5f288831931a696305706a379 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sat, 16 May 2015 01:11:37 +0200 Subject: [PATCH 09/19] Win32: lstat(): return adequate stat.st_size for symlinks Git typically doesn't trust the stat.st_size member of symlinks (e.g. see strbuf_readlink()). However, some functions take shortcuts if st_size is 0 (e.g. diff_populate_filespec()). In mingw_lstat() and fscache_lstat(), make sure to return an adequate size. The extra overhead of opening and reading the reparse point to calculate the exact size is not necessary, as git doesn't rely on the value anyway. Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- compat/mingw.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index e9625343e9..04dc34b4f4 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -750,8 +750,8 @@ int mingw_lstat(const char *file_name, struct stat *buf) buf->st_nlink = 1; buf->st_mode = file_attr_to_st_mode(fdata.dwFileAttributes, findbuf.dwReserved0); - buf->st_size = fdata.nFileSizeLow | - (((off_t)fdata.nFileSizeHigh)<<32); + buf->st_size = S_ISLNK(buf->st_mode) ? MAX_LONG_PATH : + fdata.nFileSizeLow | (((off_t) fdata.nFileSizeHigh) << 32); buf->st_dev = buf->st_rdev = 0; /* not used by Git */ filetime_to_timespec(&(fdata.ftLastAccessTime), &(buf->st_atim)); filetime_to_timespec(&(fdata.ftLastWriteTime), &(buf->st_mtim)); From 372f4d5c67913254071eb7642f13eecd84acfd16 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Tue, 19 May 2015 21:48:55 +0200 Subject: [PATCH 10/19] Win32: factor out retry logic The retry pattern is duplicated in three places. It also seems to be too hard to use: mingw_unlink() and mingw_rmdir() duplicate the code to retry, and both of them do so incompletely. They also do not restore errno if the user answers 'no'. Introduce a retry_ask_yes_no() helper function that handles retry with small delay, asking the user, and restoring errno. mingw_unlink: include _wchmod in the retry loop (which may fail if the file is locked exclusively). mingw_rmdir: include special error handling in the retry loop. Signed-off-by: Karsten Blees --- compat/mingw.c | 98 ++++++++++++++++++++++---------------------------- 1 file changed, 43 insertions(+), 55 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 04dc34b4f4..0b4eae49cf 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -14,8 +14,6 @@ #define HCAST(type, handle) ((type)(intptr_t)handle) -static const int delay[] = { 0, 1, 10, 20, 40 }; - void open_in_gdb(void) { static struct child_process cp = CHILD_PROCESS_INIT; @@ -191,15 +189,12 @@ static int read_yes_no_answer(void) return -1; } -static int ask_yes_no_if_possible(const char *format, ...) +static int ask_yes_no_if_possible(const char *format, va_list args) { char question[4096]; const char *retry_hook[] = { NULL, NULL, NULL }; - va_list args; - va_start(args, format); vsnprintf(question, sizeof(question), format, args); - va_end(args); if ((retry_hook[0] = mingw_getenv("GIT_ASK_YESNO"))) { retry_hook[1] = question; @@ -221,6 +216,31 @@ static int ask_yes_no_if_possible(const char *format, ...) } } +static int retry_ask_yes_no(int *tries, const char *format, ...) +{ + static const int delay[] = { 0, 1, 10, 20, 40 }; + va_list args; + int result, saved_errno = errno; + + if ((*tries) < ARRAY_SIZE(delay)) { + /* + * We assume that some other process had the file open at the wrong + * moment and retry. In order to give the other process a higher + * chance to complete its operation, we give up our time slice now. + * If we have to retry again, we do sleep a bit. + */ + Sleep(delay[*tries]); + (*tries)++; + return 1; + } + + va_start(args, format); + result = ask_yes_no_if_possible(format, args); + va_end(args); + errno = saved_errno; + return result; +} + /* Windows only */ enum hide_dotfiles_type { HIDE_DOTFILES_FALSE = 0, @@ -289,31 +309,21 @@ static wchar_t *normalize_ntpath(wchar_t *wbuf) int mingw_unlink(const char *pathname) { - int ret, tries = 0; + int tries = 0; wchar_t wpathname[MAX_LONG_PATH]; if (xutftowcs_long_path(wpathname, pathname) < 0) return -1; - /* read-only files cannot be removed */ - _wchmod(wpathname, 0666); - while ((ret = _wunlink(wpathname)) == -1 && tries < ARRAY_SIZE(delay)) { + do { + /* read-only files cannot be removed */ + _wchmod(wpathname, 0666); + if (!_wunlink(wpathname)) + return 0; if (!is_file_in_use_error(GetLastError())) break; - /* - * We assume that some other process had the source or - * destination file open at the wrong moment and retry. - * In order to give the other process a higher chance to - * complete its operation, we give up our time slice now. - * If we have to retry again, we do sleep a bit. - */ - Sleep(delay[tries]); - tries++; - } - while (ret == -1 && is_file_in_use_error(GetLastError()) && - ask_yes_no_if_possible("Unlink of file '%s' failed. " - "Should I try again?", pathname)) - ret = _wunlink(wpathname); - return ret; + } while (retry_ask_yes_no(&tries, "Unlink of file '%s' failed. " + "Should I try again?", pathname)); + return -1; } static int is_dir_empty(const wchar_t *wpath) @@ -340,12 +350,14 @@ static int is_dir_empty(const wchar_t *wpath) int mingw_rmdir(const char *pathname) { - int ret, tries = 0; + int tries = 0; wchar_t wpathname[MAX_LONG_PATH]; if (xutftowcs_long_path(wpathname, pathname) < 0) return -1; - while ((ret = _wrmdir(wpathname)) == -1 && tries < ARRAY_SIZE(delay)) { + do { + if (!_wrmdir(wpathname)) + return 0; if (!is_file_in_use_error(GetLastError())) errno = err_win_to_posix(GetLastError()); if (errno != EACCES) @@ -354,21 +366,9 @@ int mingw_rmdir(const char *pathname) errno = ENOTEMPTY; break; } - /* - * We assume that some other process had the source or - * destination file open at the wrong moment and retry. - * In order to give the other process a higher chance to - * complete its operation, we give up our time slice now. - * If we have to retry again, we do sleep a bit. - */ - Sleep(delay[tries]); - tries++; - } - while (ret == -1 && errno == EACCES && is_file_in_use_error(GetLastError()) && - ask_yes_no_if_possible("Deletion of directory '%s' failed. " - "Should I try again?", pathname)) - ret = _wrmdir(wpathname); - return ret; + } while (retry_ask_yes_no(&tries, "Deletion of directory '%s' failed. " + "Should I try again?", pathname)); + return -1; } static inline int needs_hiding(const char *path) @@ -1934,20 +1934,8 @@ repeat: SetFileAttributesW(wpnew, attrs); } } - if (tries < ARRAY_SIZE(delay) && gle == ERROR_ACCESS_DENIED) { - /* - * We assume that some other process had the source or - * destination file open at the wrong moment and retry. - * In order to give the other process a higher chance to - * complete its operation, we give up our time slice now. - * If we have to retry again, we do sleep a bit. - */ - Sleep(delay[tries]); - tries++; - goto repeat; - } if (gle == ERROR_ACCESS_DENIED && - ask_yes_no_if_possible("Rename from '%s' to '%s' failed. " + retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. " "Should I try again?", pold, pnew)) goto repeat; From 6f88e75226df030045f63b8d0c38b5c5accc0071 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 01:55:05 +0200 Subject: [PATCH 11/19] Win32: change default of 'core.symlinks' to false Symlinks on Windows don't work the same way as on Unix systems. E.g. there are different types of symlinks for directories and files, creating symlinks requires administrative privileges etc. By default, disable symlink support on Windows. I.e. users explicitly have to enable it with 'git config [--system|--global] core.symlinks true'. The test suite ignores system / global config files. Allow testing *with* symlink support by checking if native symlinks are enabled in MSys2 (via 'MSYS=winsymlinks:nativestrict'). Reminder: This would need to be changed if / when we find a way to run the test suite in a non-MSys-based shell (e.g. dash). Signed-off-by: Karsten Blees --- compat/mingw.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/compat/mingw.c b/compat/mingw.c index 0b4eae49cf..ba9d8736b9 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -2425,6 +2425,15 @@ static void setup_windows_environment(void) setenv("HOME", tmp, 1); } + /* + * Change 'core.symlinks' default to false, unless native symlinks are + * enabled in MSys2 (via 'MSYS=winsymlinks:nativestrict'). Thus we can + * run the test suite (which doesn't obey config files) with or without + * symlink support. + */ + if (!(tmp = getenv("MSYS")) || !strstr(tmp, "winsymlinks:nativestrict")) + has_symlinks = 0; + if (!getenv("LC_ALL") && !getenv("LC_CTYPE") && !getenv("LANG")) setenv("LC_CTYPE", "C", 1); } From 91ec6cebdf6d3bc70cce4444e1bd4ae75f26b7c7 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sat, 16 May 2015 00:32:03 +0200 Subject: [PATCH 12/19] Win32: add symlink-specific error codes Signed-off-by: Karsten Blees --- compat/mingw.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/compat/mingw.c b/compat/mingw.c index ba9d8736b9..88580e2c10 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -89,6 +89,7 @@ int err_win_to_posix(DWORD winerr) case ERROR_INVALID_PARAMETER: error = EINVAL; break; case ERROR_INVALID_PASSWORD: error = EPERM; break; case ERROR_INVALID_PRIMARY_GROUP: error = EINVAL; break; + case ERROR_INVALID_REPARSE_DATA: error = EINVAL; break; case ERROR_INVALID_SIGNAL_NUMBER: error = EINVAL; break; case ERROR_INVALID_TARGET_HANDLE: error = EIO; break; case ERROR_INVALID_WORKSTATION: error = EACCES; break; @@ -103,6 +104,7 @@ int err_win_to_posix(DWORD winerr) case ERROR_NEGATIVE_SEEK: error = ESPIPE; break; case ERROR_NOACCESS: error = EFAULT; break; case ERROR_NONE_MAPPED: error = EINVAL; break; + case ERROR_NOT_A_REPARSE_POINT: error = EINVAL; break; case ERROR_NOT_ENOUGH_MEMORY: error = ENOMEM; break; case ERROR_NOT_READY: error = EAGAIN; break; case ERROR_NOT_SAME_DEVICE: error = EXDEV; break; @@ -123,6 +125,9 @@ int err_win_to_posix(DWORD winerr) case ERROR_PIPE_NOT_CONNECTED: error = EPIPE; break; case ERROR_PRIVILEGE_NOT_HELD: error = EACCES; break; case ERROR_READ_FAULT: error = EIO; break; + case ERROR_REPARSE_ATTRIBUTE_CONFLICT: error = EINVAL; break; + case ERROR_REPARSE_TAG_INVALID: error = EINVAL; break; + case ERROR_REPARSE_TAG_MISMATCH: error = EINVAL; break; case ERROR_SEEK: error = EIO; break; case ERROR_SEEK_ON_DEVICE: error = ESPIPE; break; case ERROR_SHARING_BUFFER_EXCEEDED: error = ENFILE; break; From 0f1a2a7ff8f975f97d8c6c14a5e2d83386285c40 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 01:06:10 +0200 Subject: [PATCH 13/19] Win32: mingw_unlink: support symlinks to directories _wunlink() / DeleteFileW() refuses to delete symlinks to directories. If _wunlink() fails with ERROR_ACCESS_DENIED, try _wrmdir() as well. Signed-off-by: Karsten Blees --- compat/mingw.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/compat/mingw.c b/compat/mingw.c index 88580e2c10..5c94a74487 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -326,6 +326,13 @@ int mingw_unlink(const char *pathname) return 0; if (!is_file_in_use_error(GetLastError())) break; + /* + * _wunlink() / DeleteFileW() for directory symlinks fails with + * ERROR_ACCESS_DENIED (EACCES), so try _wrmdir() as well. This is the + * same error we get if a file is in use (already checked above). + */ + if (!_wrmdir(wpathname)) + return 0; } while (retry_ask_yes_no(&tries, "Unlink of file '%s' failed. " "Should I try again?", pathname)); return -1; From 70bfb4364c9f761ef764ebc3f8edd3cde34b1d63 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Tue, 19 May 2015 22:42:48 +0200 Subject: [PATCH 14/19] Win32: mingw_rename: support renaming symlinks MSVCRT's _wrename() cannot rename symlinks over existing files: it returns success without doing anything. Newer MSVCR*.dll versions probably do not have this problem: according to CRT sources, they just call MoveFileEx() with the MOVEFILE_COPY_ALLOWED flag. Get rid of _wrename() and call MoveFileEx() with proper error handling. Signed-off-by: Karsten Blees --- compat/mingw.c | 38 +++++++++++++++++--------------------- 1 file changed, 17 insertions(+), 21 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 5c94a74487..9e4830300d 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -1906,27 +1906,29 @@ int mingw_accept(int sockfd1, struct sockaddr *sa, socklen_t *sz) #undef rename int mingw_rename(const char *pold, const char *pnew) { - DWORD attrs, gle; + DWORD attrs = INVALID_FILE_ATTRIBUTES, gle; int tries = 0; wchar_t wpold[MAX_LONG_PATH], wpnew[MAX_LONG_PATH]; if (xutftowcs_long_path(wpold, pold) < 0 || xutftowcs_long_path(wpnew, pnew) < 0) return -1; - /* - * Try native rename() first to get errno right. - * It is based on MoveFile(), which cannot overwrite existing files. - */ - if (!_wrename(wpold, wpnew)) - return 0; - if (errno != EEXIST) - return -1; repeat: - if (MoveFileExW(wpold, wpnew, MOVEFILE_REPLACE_EXISTING)) + if (MoveFileExW(wpold, wpnew, + MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED)) return 0; - /* TODO: translate more errors */ gle = GetLastError(); - if (gle == ERROR_ACCESS_DENIED && + + /* revert file attributes on failure */ + if (attrs != INVALID_FILE_ATTRIBUTES) + SetFileAttributesW(wpnew, attrs); + + if (!is_file_in_use_error(gle)) { + errno = err_win_to_posix(gle); + return -1; + } + + if (attrs == INVALID_FILE_ATTRIBUTES && (attrs = GetFileAttributesW(wpnew)) != INVALID_FILE_ATTRIBUTES) { if (attrs & FILE_ATTRIBUTE_DIRECTORY) { DWORD attrsold = GetFileAttributesW(wpold); @@ -1938,16 +1940,10 @@ repeat: return -1; } if ((attrs & FILE_ATTRIBUTE_READONLY) && - SetFileAttributesW(wpnew, attrs & ~FILE_ATTRIBUTE_READONLY)) { - if (MoveFileExW(wpold, wpnew, MOVEFILE_REPLACE_EXISTING)) - return 0; - gle = GetLastError(); - /* revert file attributes on failure */ - SetFileAttributesW(wpnew, attrs); - } + SetFileAttributesW(wpnew, attrs & ~FILE_ATTRIBUTE_READONLY)) + goto repeat; } - if (gle == ERROR_ACCESS_DENIED && - retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. " + if (retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. " "Should I try again?", pold, pnew)) goto repeat; From 32ffa526a2b7f5b80bb77de2dfa12f678e8ae100 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 01:17:31 +0200 Subject: [PATCH 15/19] Win32: mingw_chdir: change to symlink-resolved directory If symlinks are enabled, resolve all symlinks when changing directories, as required by POSIX. Note: Git's real_path() function bases its link resolution algorithm on this property of chdir(). Unfortunately, the current directory on Windows is limited to only MAX_PATH (260) characters. Therefore using symlinks and long paths in combination may be problematic. Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- compat/mingw.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/compat/mingw.c b/compat/mingw.c index 9e4830300d..49d1fec349 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -685,7 +685,24 @@ int mingw_chdir(const char *dirname) wchar_t wdirname[MAX_LONG_PATH]; if (xutftowcs_long_path(wdirname, dirname) < 0) return -1; - result = _wchdir(wdirname); + + if (has_symlinks) { + HANDLE hnd = CreateFileW(wdirname, 0, + FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, + OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL); + if (hnd == INVALID_HANDLE_VALUE) { + errno = err_win_to_posix(GetLastError()); + return -1; + } + if (!GetFinalPathNameByHandleW(hnd, wdirname, ARRAY_SIZE(wdirname), 0)) { + errno = err_win_to_posix(GetLastError()); + CloseHandle(hnd); + return -1; + } + CloseHandle(hnd); + } + + result = _wchdir(normalize_ntpath(wdirname)); current_directory_len = GetCurrentDirectoryW(0, NULL); return result; } From b16097ddd4e6e67e0b3bb3dd6fd4db17a7ae412f Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 01:24:41 +0200 Subject: [PATCH 16/19] Win32: implement readlink() Implement readlink() by reading NTFS reparse points. Works for symlinks and directory junctions. If symlinks are disabled, fail with ENOSYS. Signed-off-by: Karsten Blees --- compat/mingw.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++ compat/mingw.h | 3 +- 2 files changed, 99 insertions(+), 2 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 49d1fec349..cd28d11ca8 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -4,6 +4,7 @@ #include #include #include +#include #include "../strbuf.h" #include "../run-command.h" #include "../cache.h" @@ -2237,6 +2238,103 @@ int link(const char *oldpath, const char *newpath) return 0; } +#ifndef _WINNT_H +/* + * The REPARSE_DATA_BUFFER structure is defined in the Windows DDK (in + * ntifs.h) and in MSYS1's winnt.h (which defines _WINNT_H). So define + * it ourselves if we are on MSYS2 (whose winnt.h defines _WINNT_). + */ +typedef struct _REPARSE_DATA_BUFFER { + DWORD ReparseTag; + WORD ReparseDataLength; + WORD Reserved; +#ifndef _MSC_VER + _ANONYMOUS_UNION +#endif + union { + struct { + WORD SubstituteNameOffset; + WORD SubstituteNameLength; + WORD PrintNameOffset; + WORD PrintNameLength; + ULONG Flags; + WCHAR PathBuffer[1]; + } SymbolicLinkReparseBuffer; + struct { + WORD SubstituteNameOffset; + WORD SubstituteNameLength; + WORD PrintNameOffset; + WORD PrintNameLength; + WCHAR PathBuffer[1]; + } MountPointReparseBuffer; + struct { + BYTE DataBuffer[1]; + } GenericReparseBuffer; + } DUMMYUNIONNAME; +} REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER; +#endif + +int readlink(const char *path, char *buf, size_t bufsiz) +{ + HANDLE handle; + WCHAR wpath[MAX_LONG_PATH], *wbuf; + REPARSE_DATA_BUFFER *b = alloca(MAXIMUM_REPARSE_DATA_BUFFER_SIZE); + DWORD dummy; + char tmpbuf[MAX_LONG_PATH]; + int len; + + if (xutftowcs_long_path(wpath, path) < 0) + return -1; + + /* read reparse point data */ + handle = CreateFileW(wpath, 0, + FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, + OPEN_EXISTING, + FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL); + if (handle == INVALID_HANDLE_VALUE) { + errno = err_win_to_posix(GetLastError()); + return -1; + } + if (!DeviceIoControl(handle, FSCTL_GET_REPARSE_POINT, NULL, 0, b, + MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &dummy, NULL)) { + errno = err_win_to_posix(GetLastError()); + CloseHandle(handle); + return -1; + } + CloseHandle(handle); + + /* get target path for symlinks or mount points (aka 'junctions') */ + switch (b->ReparseTag) { + case IO_REPARSE_TAG_SYMLINK: + wbuf = (WCHAR*) (((char*) b->SymbolicLinkReparseBuffer.PathBuffer) + + b->SymbolicLinkReparseBuffer.SubstituteNameOffset); + *(WCHAR*) (((char*) wbuf) + + b->SymbolicLinkReparseBuffer.SubstituteNameLength) = 0; + break; + case IO_REPARSE_TAG_MOUNT_POINT: + wbuf = (WCHAR*) (((char*) b->MountPointReparseBuffer.PathBuffer) + + b->MountPointReparseBuffer.SubstituteNameOffset); + *(WCHAR*) (((char*) wbuf) + + b->MountPointReparseBuffer.SubstituteNameLength) = 0; + break; + default: + errno = EINVAL; + return -1; + } + + /* + * Adapt to strange readlink() API: Copy up to bufsiz *bytes*, potentially + * cutting off a UTF-8 sequence. Insufficient bufsize is *not* a failure + * condition. There is no conversion function that produces invalid UTF-8, + * so convert to a (hopefully large enough) temporary buffer, then memcpy + * the requested number of bytes (including '\0' for robustness). + */ + if ((len = xwcstoutf(tmpbuf, normalize_ntpath(wbuf), MAX_LONG_PATH)) < 0) + return -1; + memcpy(buf, tmpbuf, min(bufsiz, len + 1)); + return min(bufsiz, len); +} + pid_t waitpid(pid_t pid, int *status, int options) { HANDLE h = OpenProcess(SYNCHRONIZE | PROCESS_QUERY_INFORMATION, diff --git a/compat/mingw.h b/compat/mingw.h index d9275da26a..701e9b013f 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -123,8 +123,6 @@ struct utsname { * trivial stubs */ -static inline int readlink(const char *path, char *buf, size_t bufsiz) -{ errno = ENOSYS; return -1; } static inline int symlink(const char *oldpath, const char *newpath) { errno = ENOSYS; return -1; } static inline int fchmod(int fildes, mode_t mode) @@ -217,6 +215,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out); int sigaction(int sig, struct sigaction *in, struct sigaction *out); int link(const char *oldpath, const char *newpath); int uname(struct utsname *buf); +int readlink(const char *path, char *buf, size_t bufsiz); /* * replacements of existing functions From 899ea12ffc62e65ad706d9c4ea87cfd4efdd50fb Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 01:32:03 +0200 Subject: [PATCH 17/19] Win32: implement basic symlink() functionality (file symlinks only) Implement symlink() that always creates file symlinks. Fails with ENOSYS if symlinks are disabled or unsupported. Note: CreateSymbolicLinkW() was introduced with symlink support in Windows Vista. For compatibility with Windows XP, we need to load it dynamically and fail gracefully if it isnt's available. Signed-off-by: Karsten Blees --- compat/mingw.c | 28 ++++++++++++++++++++++++++++ compat/mingw.h | 3 +-- 2 files changed, 29 insertions(+), 2 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index cd28d11ca8..f940aabff9 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -2238,6 +2238,34 @@ int link(const char *oldpath, const char *newpath) return 0; } +int symlink(const char *target, const char *link) +{ + wchar_t wtarget[MAX_LONG_PATH], wlink[MAX_LONG_PATH]; + int len; + + /* fail if symlinks are disabled or API is not supported (WinXP) */ + if (!has_symlinks) { + errno = ENOSYS; + return -1; + } + + if ((len = xutftowcs_long_path(wtarget, target)) < 0 + || xutftowcs_long_path(wlink, link) < 0) + return -1; + + /* convert target dir separators to backslashes */ + while (len--) + if (wtarget[len] == '/') + wtarget[len] = '\\'; + + /* create file symlink */ + if (!CreateSymbolicLinkW(wlink, wtarget, 0)) { + errno = err_win_to_posix(GetLastError()); + return -1; + } + return 0; +} + #ifndef _WINNT_H /* * The REPARSE_DATA_BUFFER structure is defined in the Windows DDK (in diff --git a/compat/mingw.h b/compat/mingw.h index 701e9b013f..f1b3ae36ae 100644 --- a/compat/mingw.h +++ b/compat/mingw.h @@ -123,8 +123,6 @@ struct utsname { * trivial stubs */ -static inline int symlink(const char *oldpath, const char *newpath) -{ errno = ENOSYS; return -1; } static inline int fchmod(int fildes, mode_t mode) { errno = ENOSYS; return -1; } #ifndef __MINGW64_VERSION_MAJOR @@ -215,6 +213,7 @@ int setitimer(int type, struct itimerval *in, struct itimerval *out); int sigaction(int sig, struct sigaction *in, struct sigaction *out); int link(const char *oldpath, const char *newpath); int uname(struct utsname *buf); +int symlink(const char *target, const char *link); int readlink(const char *path, char *buf, size_t bufsiz); /* From 301bd6ac3793f813d3c9a1353a2b15a33b43f26e Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sun, 24 May 2015 01:48:35 +0200 Subject: [PATCH 18/19] Win32: symlink: add support for symlinks to directories Symlinks on Windows have a flag that indicates whether the target is a file or a directory. Symlinks of wrong type simply don't work. This even affects core Win32 APIs (e.g. DeleteFile() refuses to delete directory symlinks). However, CreateFile() with FILE_FLAG_BACKUP_SEMANTICS doesn't seem to care. Check the target type by first creating a tentative file symlink, opening it, and checking the type of the resulting handle. If it is a directory, recreate the symlink with the directory flag set. It is possible to create symlinks before the target exists (or in case of symlinks to symlinks: before the target type is known). If this happens, create a tentative file symlink and postpone the directory decision: keep a list of phantom symlinks to be processed whenever a new directory is created in mingw_mkdir(). Limitations: This algorithm may fail if a link target changes from file to directory or vice versa, or if the target directory is created in another process. Signed-off-by: Karsten Blees Signed-off-by: Johannes Schindelin --- compat/mingw.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 164 insertions(+) diff --git a/compat/mingw.c b/compat/mingw.c index f940aabff9..7eccd6040b 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -288,6 +288,131 @@ int mingw_core_config(const char *var, const char *value, void *cb) return 0; } +enum phantom_symlink_result { + PHANTOM_SYMLINK_RETRY, + PHANTOM_SYMLINK_DONE, + PHANTOM_SYMLINK_DIRECTORY +}; + +static inline int is_wdir_sep(wchar_t wchar) +{ + return wchar == L'/' || wchar == L'\\'; +} + +static const wchar_t *make_relative_to(const wchar_t *path, + const wchar_t *relative_to, wchar_t *out, + size_t size) +{ + size_t i = wcslen(relative_to), len; + + /* Is `path` already absolute? */ + if (is_wdir_sep(path[0]) || + (iswalpha(path[0]) && path[1] == L':' && is_wdir_sep(path[2]))) + return path; + + while (i > 0 && !is_wdir_sep(relative_to[i - 1])) + i--; + + /* Is `relative_to` in the current directory? */ + if (!i) + return path; + + len = wcslen(path); + if (i + len + 1 > size) { + error("Could not make '%S' relative to '%S' (too large)", + path, relative_to); + return NULL; + } + + memcpy(out, relative_to, i * sizeof(wchar_t)); + wcscpy(out + i, path); + return out; +} + +/* + * Changes a file symlink to a directory symlink if the target exists and is a + * directory. + */ +static enum phantom_symlink_result +process_phantom_symlink(const wchar_t *wtarget, const wchar_t *wlink) +{ + HANDLE hnd; + BY_HANDLE_FILE_INFORMATION fdata; + wchar_t relative[MAX_LONG_PATH]; + const wchar_t *rel; + + /* check that wlink is still a file symlink */ + if ((GetFileAttributesW(wlink) + & (FILE_ATTRIBUTE_REPARSE_POINT | FILE_ATTRIBUTE_DIRECTORY)) + != FILE_ATTRIBUTE_REPARSE_POINT) + return PHANTOM_SYMLINK_DONE; + + /* make it relative, if necessary */ + rel = make_relative_to(wtarget, wlink, relative, ARRAY_SIZE(relative)); + if (!rel) + return PHANTOM_SYMLINK_DONE; + + /* let Windows resolve the link by opening it */ + hnd = CreateFileW(rel, 0, + FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, + OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL); + if (hnd == INVALID_HANDLE_VALUE) { + errno = err_win_to_posix(GetLastError()); + return PHANTOM_SYMLINK_RETRY; + } + + if (!GetFileInformationByHandle(hnd, &fdata)) { + errno = err_win_to_posix(GetLastError()); + CloseHandle(hnd); + return PHANTOM_SYMLINK_RETRY; + } + CloseHandle(hnd); + + /* if target exists and is a file, we're done */ + if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) + return PHANTOM_SYMLINK_DONE; + + /* otherwise recreate the symlink with directory flag */ + if (DeleteFileW(wlink) && CreateSymbolicLinkW(wlink, wtarget, 1)) + return PHANTOM_SYMLINK_DIRECTORY; + + errno = err_win_to_posix(GetLastError()); + return PHANTOM_SYMLINK_RETRY; +} + +/* keep track of newly created symlinks to non-existing targets */ +struct phantom_symlink_info { + struct phantom_symlink_info *next; + wchar_t *wlink; + wchar_t *wtarget; +}; + +static struct phantom_symlink_info *phantom_symlinks = NULL; +static CRITICAL_SECTION phantom_symlinks_cs; + +static void process_phantom_symlinks(void) +{ + struct phantom_symlink_info *current, **psi; + EnterCriticalSection(&phantom_symlinks_cs); + /* process phantom symlinks list */ + psi = &phantom_symlinks; + while ((current = *psi)) { + enum phantom_symlink_result result = process_phantom_symlink( + current->wtarget, current->wlink); + if (result == PHANTOM_SYMLINK_RETRY) { + psi = ¤t->next; + } else { + /* symlink was processed, remove from list */ + *psi = current->next; + free(current); + /* if symlink was a directory, start over */ + if (result == PHANTOM_SYMLINK_DIRECTORY) + psi = &phantom_symlinks; + } + } + LeaveCriticalSection(&phantom_symlinks_cs); +} + /* Normalizes NT paths as returned by some low-level APIs. */ static wchar_t *normalize_ntpath(wchar_t *wbuf) { @@ -437,6 +562,8 @@ int mingw_mkdir(const char *path, int mode) return -1; ret = _wmkdir(wpath); + if (!ret) + process_phantom_symlinks(); if (!ret && needs_hiding(path)) return set_hidden_flag(wpath, 1); return ret; @@ -2263,6 +2390,42 @@ int symlink(const char *target, const char *link) errno = err_win_to_posix(GetLastError()); return -1; } + + /* convert to directory symlink if target exists */ + switch (process_phantom_symlink(wtarget, wlink)) { + case PHANTOM_SYMLINK_RETRY: { + /* if target doesn't exist, add to phantom symlinks list */ + wchar_t wfullpath[MAX_LONG_PATH]; + struct phantom_symlink_info *psi; + + /* convert to absolute path to be independent of cwd */ + len = GetFullPathNameW(wlink, MAX_LONG_PATH, wfullpath, NULL); + if (!len || len >= MAX_LONG_PATH) { + errno = err_win_to_posix(GetLastError()); + return -1; + } + + /* over-allocate and fill phantom_symlink_info structure */ + psi = xmalloc(sizeof(struct phantom_symlink_info) + + sizeof(wchar_t) * (len + wcslen(wtarget) + 2)); + psi->wlink = (wchar_t *)(psi + 1); + wcscpy(psi->wlink, wfullpath); + psi->wtarget = psi->wlink + len + 1; + wcscpy(psi->wtarget, wtarget); + + EnterCriticalSection(&phantom_symlinks_cs); + psi->next = phantom_symlinks; + phantom_symlinks = psi; + LeaveCriticalSection(&phantom_symlinks_cs); + break; + } + case PHANTOM_SYMLINK_DIRECTORY: + /* if we created a dir symlink, process other phantom symlinks */ + process_phantom_symlinks(); + break; + default: + break; + } return 0; } @@ -2799,6 +2962,7 @@ int wmain(int argc, const wchar_t **wargv) /* initialize critical section for waitpid pinfo_t list */ InitializeCriticalSection(&pinfo_cs); + InitializeCriticalSection(&phantom_symlinks_cs); /* initialize critical section for fscache */ InitializeCriticalSection(&fscache_cs); From d46afda2252d47e928a064f74300e5f392ce6fd3 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Tue, 30 May 2017 21:50:57 +0200 Subject: [PATCH 19/19] mingw: try to create symlinks without elevated permissions With Windows 10 Build 14972 in Developer Mode, a new flag is supported by CreateSymbolicLink() to create symbolic links even when running outside of an elevated session (which was previously required). This new flag is called SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE and has the numeric value 0x02. Previous Windows 10 versions will not understand that flag and return an ERROR_INVALID_PARAMETER, therefore we have to be careful to try passing that flag only when the build number indicates that it is supported. For more information about the new flag, see this blog post: https://blogs.windows.com/buildingapps/2016/12/02/symlinks-windows-10/ This patch is loosely based on the patch submitted by Samuel D. Leslie as https://github.com/git-for-windows/git/pull/1184. Signed-off-by: Johannes Schindelin --- compat/mingw.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 7eccd6040b..9c4fb43e8a 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -288,6 +288,8 @@ int mingw_core_config(const char *var, const char *value, void *cb) return 0; } +static DWORD symlink_file_flags = 0, symlink_directory_flags = 1; + enum phantom_symlink_result { PHANTOM_SYMLINK_RETRY, PHANTOM_SYMLINK_DONE, @@ -373,7 +375,8 @@ process_phantom_symlink(const wchar_t *wtarget, const wchar_t *wlink) return PHANTOM_SYMLINK_DONE; /* otherwise recreate the symlink with directory flag */ - if (DeleteFileW(wlink) && CreateSymbolicLinkW(wlink, wtarget, 1)) + if (DeleteFileW(wlink) && + CreateSymbolicLinkW(wlink, wtarget, symlink_directory_flags)) return PHANTOM_SYMLINK_DIRECTORY; errno = err_win_to_posix(GetLastError()); @@ -2386,7 +2389,7 @@ int symlink(const char *target, const char *link) wtarget[len] = '\\'; /* create file symlink */ - if (!CreateSymbolicLinkW(wlink, wtarget, 0)) { + if (!CreateSymbolicLinkW(wlink, wtarget, symlink_file_flags)) { errno = err_win_to_posix(GetLastError()); return -1; } @@ -2898,6 +2901,24 @@ static void maybe_redirect_std_handles(void) GENERIC_WRITE, FILE_FLAG_NO_BUFFERING); } +static void adjust_symlink_flags(void) +{ + /* + * Starting with Windows 10 Build 14972, symbolic links can be created + * using CreateSymbolicLink() without elevation by passing the flag + * SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE (0x02) as last + * parameter, provided the Developer Mode has been enabled. Some + * earlier Windows versions complain about this flag with an + * ERROR_INVALID_PARAMETER, hence we have to test the build number + * specifically. + */ + if (GetVersion() >= 14972 << 16) { + symlink_file_flags |= 2; + symlink_directory_flags |= 2; + } + +} + #ifdef _MSC_VER #ifdef _DEBUG #include @@ -2932,6 +2953,7 @@ int wmain(int argc, const wchar_t **wargv) #endif maybe_redirect_std_handles(); + adjust_symlink_flags(); fsync_object_files = 1; /* determine size of argv and environ conversion buffer */