Merge branch 'kblees/kb/symlinks'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

compat/mingw.h

@@ -125,10 +125,6 @@ struct utsname {
  * trivial stubs
  */
 
-static inline int readlink(const char *path UNUSED, char *buf UNUSED, size_t bufsiz UNUSED)
-{ errno = ENOSYS; return -1; }
-static inline int symlink(const char *oldpath UNUSED, const char *newpath UNUSED)
-{ errno = ENOSYS; return -1; }
 static inline int fchmod(int fildes UNUSED, mode_t mode UNUSED)
 { errno = ENOSYS; return -1; }
 #ifndef __MINGW64_VERSION_MAJOR
@@ -222,6 +218,8 @@ 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);
 
 /*
  * replacements of existing functions

compat/win32.h

@@ -6,10 +6,12 @@
 #include <windows.h>
 #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;

compat/win32/dirent.c

@@ -18,7 +18,10 @@ 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;

compat/win32/fscache.c

@@ -202,10 +202,13 @@ static struct fsentry *fseentry_create_entry(struct fscache *cache,
 		fdata->FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT ?
 		fdata->EaSize : 0;
 
-	fse->st_mode = file_attr_to_st_mode(fdata->FileAttributes);
-	fse->dirent.d_type = S_ISDIR(fse->st_mode) ? DT_DIR : DT_REG;
-	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->dirent.d_type = S_ISREG(fse->st_mode) ? DT_REG :
+			S_ISDIR(fse->st_mode) ? DT_DIR : DT_LNK;
+	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),
@@ -581,6 +584,18 @@ int fscache_lstat(const char *filename, struct stat *st)
 		return -1;
 	}
 
+	/*
+	 * Special case symbolic links: FindFirstFile()/FindNextFile() did not
+	 * provide us with the length of the target path.
+	 */
+	if (fse->u.s.st_size == MAX_LONG_PATH && S_ISLNK(fse->st_mode)) {
+		char buf[MAX_LONG_PATH];
+		int len = readlink(filename, buf, sizeof(buf) - 1);
+
+		if (len > 0)
+			fse->u.s.st_size = len;
+	}
+
 	/* copy stat data */
 	st->st_ino = 0;
 	st->st_gid = 0;

lockfile.c

@@ -19,14 +19,14 @@ 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);

read-cache.c

@@ -470,6 +470,17 @@ int ie_modified(struct index_state *istate,
 	 * then we know it is.
 	 */
 	if ((changed & DATA_CHANGED) &&
+#ifdef GIT_WINDOWS_NATIVE
+	    /*
+	     * Work around Git for Windows v2.27.0 fixing a bug where symlinks'
+	     * target path lengths were not read at all, and instead recorded
+	     * as 4096: now, all symlinks would appear as modified.
+	     *
+	     * So let's just special-case symlinks with a target path length
+	     * (i.e. `sd_size`) of 4096 and force them to be re-checked.
+	     */
+	    (!S_ISLNK(st->st_mode) || ce->ce_stat_data.sd_size != MAX_LONG_PATH) &&
+#endif
 	    (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0))
 		return changed;
 

strbuf.c

@@ -562,24 +562,22 @@ ssize_t strbuf_write(struct strbuf *sb, FILE *f)
 	return sb->len ? fwrite(sb->buf, 1, sb->len, f) : 0;
 }
 
-#define STRBUF_MAXLINK (2*PATH_MAX)
-
 int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 {
 	size_t oldalloc = sb->alloc;
 
 	if (hint < 32)
 		hint = 32;
 
-	while (hint < STRBUF_MAXLINK) {
+	for (;;) {
 		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;
 		}