1 files changed, 480 insertions, 68 deletions

diff --git a/path.c b/path.c
index 334b2bd195..6f3f5d56c0 100644
--- a/path.c
+++ b/path.c
@@ -11,11 +11,17 @@
  * which is what it's designed for.
  */
 #include "cache.h"
-#include <pwd.h>
+#include "strbuf.h"
 
-static char pathname[PATH_MAX];
 static char bad_path[] = "/bad-path/";
 
+static char *get_pathname(void)
+{
+	static char pathname_array[4][PATH_MAX];
+	static int index;
+	return pathname_array[3 & ++index];
+}
+
 static char *cleanup_path(char *path)
 {
 	/* Clean it up */
@@ -27,10 +33,65 @@ static char *cleanup_path(char *path)
 	return path;
 }
 
+char *mksnpath(char *buf, size_t n, const char *fmt, ...)
+{
+	va_list args;
+	unsigned len;
+
+	va_start(args, fmt);
+	len = vsnprintf(buf, n, fmt, args);
+	va_end(args);
+	if (len >= n) {
+		strlcpy(buf, bad_path, n);
+		return buf;
+	}
+	return cleanup_path(buf);
+}
+
+static char *git_vsnpath(char *buf, size_t n, const char *fmt, va_list args)
+{
+	const char *git_dir = get_git_dir();
+	size_t len;
+
+	len = strlen(git_dir);
+	if (n < len + 1)
+		goto bad;
+	memcpy(buf, git_dir, len);
+	if (len && !is_dir_sep(git_dir[len-1]))
+		buf[len++] = '/';
+	len += vsnprintf(buf + len, n - len, fmt, args);
+	if (len >= n)
+		goto bad;
+	return cleanup_path(buf);
+bad:
+	strlcpy(buf, bad_path, n);
+	return buf;
+}
+
+char *git_snpath(char *buf, size_t n, const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	(void)git_vsnpath(buf, n, fmt, args);
+	va_end(args);
+	return buf;
+}
+
+char *git_pathdup(const char *fmt, ...)
+{
+	char path[PATH_MAX];
+	va_list args;
+	va_start(args, fmt);
+	(void)git_vsnpath(path, sizeof(path), fmt, args);
+	va_end(args);
+	return xstrdup(path);
+}
+
 char *mkpath(const char *fmt, ...)
 {
 	va_list args;
 	unsigned len;
+	char *pathname = get_pathname();
 
 	va_start(args, fmt);
 	len = vsnprintf(pathname, PATH_MAX, fmt, args);
@@ -43,6 +104,7 @@ char *mkpath(const char *fmt, ...)
 char *git_path(const char *fmt, ...)
 {
 	const char *git_dir = get_git_dir();
+	char *pathname = get_pathname();
 	va_list args;
 	unsigned len;
 
@@ -60,42 +122,52 @@ char *git_path(const char *fmt, ...)
 	return cleanup_path(pathname);
 }
 
-
-/* git_mkstemp() - create tmp file honoring TMPDIR variable */
-int git_mkstemp(char *path, size_t len, const char *template)
+char *git_path_submodule(const char *path, const char *fmt, ...)
 {
-	char *env, *pch = path;
-
-	if ((env = getenv("TMPDIR")) == NULL) {
-		strcpy(pch, "/tmp/");
-		len -= 5;
-		pch += 5;
-	} else {
-		size_t n = snprintf(pch, len, "%s/", env);
+	char *pathname = get_pathname();
+	struct strbuf buf = STRBUF_INIT;
+	const char *git_dir;
+	va_list args;
+	unsigned len;
 
-		len -= n;
-		pch += n;
-	}
+	len = strlen(path);
+	if (len > PATH_MAX-100)
+		return bad_path;
 
-	safe_strncpy(pch, template, len);
+	strbuf_addstr(&buf, path);
+	if (len && path[len-1] != '/')
+		strbuf_addch(&buf, '/');
+	strbuf_addstr(&buf, ".git");
 
-	return mkstemp(path);
-}
+	git_dir = read_gitfile(buf.buf);
+	if (git_dir) {
+		strbuf_reset(&buf);
+		strbuf_addstr(&buf, git_dir);
+	}
+	strbuf_addch(&buf, '/');
 
+	if (buf.len >= PATH_MAX)
+		return bad_path;
+	memcpy(pathname, buf.buf, buf.len + 1);
 
-char *safe_strncpy(char *dest, const char *src, size_t n)
-{
-	strncpy(dest, src, n);
-	dest[n - 1] = '\0';
+	strbuf_release(&buf);
+	len = strlen(pathname);
 
-	return dest;
+	va_start(args, fmt);
+	len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
+	va_end(args);
+	if (len >= PATH_MAX)
+		return bad_path;
+	return cleanup_path(pathname);
 }
 
-int validate_symref(const char *path)
+int validate_headref(const char *path)
 {
 	struct stat st;
 	char *buf, buffer[256];
-	int len, fd;
+	unsigned char sha1[20];
+	int fd;
+	ssize_t len;
 
 	if (lstat(path, &st) < 0)
 		return -1;
@@ -114,60 +186,77 @@ int validate_symref(const char *path)
 	fd = open(path, O_RDONLY);
 	if (fd < 0)
 		return -1;
-	len = read(fd, buffer, sizeof(buffer)-1);
+	len = read_in_full(fd, buffer, sizeof(buffer)-1);
 	close(fd);
 
 	/*
 	 * Is it a symbolic ref?
 	 */
-	if (len < 4 || memcmp("ref:", buffer, 4))
+	if (len < 4)
 		return -1;
-	buf = buffer + 4;
-	len -= 4;
-	while (len && isspace(*buf))
-		buf++, len--;
-	if (len >= 5 && !memcmp("refs/", buf, 5))
+	if (!memcmp("ref:", buffer, 4)) {
+		buf = buffer + 4;
+		len -= 4;
+		while (len && isspace(*buf))
+			buf++, len--;
+		if (len >= 5 && !memcmp("refs/", buf, 5))
+			return 0;
+	}
+
+	/*
+	 * Is this a detached HEAD?
+	 */
+	if (!get_sha1_hex(buffer, sha1))
 		return 0;
+
 	return -1;
 }
 
-static char *user_path(char *buf, char *path, int sz)
+static struct passwd *getpw_str(const char *username, size_t len)
 {
 	struct passwd *pw;
-	char *slash;
-	int len, baselen;
+	char *username_z = xmalloc(len + 1);
+	memcpy(username_z, username, len);
+	username_z[len] = '\0';
+	pw = getpwnam(username_z);
+	free(username_z);
+	return pw;
+}
 
-	if (!path || path[0] != '~')
-		return NULL;
-	path++;
-	slash = strchr(path, '/');
-	if (path[0] == '/' || !path[0]) {
-		pw = getpwuid(getuid());
-	}
-	else {
-		if (slash) {
-			*slash = 0;
-			pw = getpwnam(path);
-			*slash = '/';
+/*
+ * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
+ * then it is a newly allocated string. Returns NULL on getpw failure or
+ * if path is NULL.
+ */
+char *expand_user_path(const char *path)
+{
+	struct strbuf user_path = STRBUF_INIT;
+	const char *first_slash = strchrnul(path, '/');
+	const char *to_copy = path;
+
+	if (path == NULL)
+		goto return_null;
+	if (path[0] == '~') {
+		const char *username = path + 1;
+		size_t username_len = first_slash - username;
+		if (username_len == 0) {
+			const char *home = getenv("HOME");
+			if (!home)
+				goto return_null;
+			strbuf_add(&user_path, home, strlen(home));
+		} else {
+			struct passwd *pw = getpw_str(username, username_len);
+			if (!pw)
+				goto return_null;
+			strbuf_add(&user_path, pw->pw_dir, strlen(pw->pw_dir));
 		}
-		else
-			pw = getpwnam(path);
+		to_copy = first_slash;
 	}
-	if (!pw || !pw->pw_dir || sz <= strlen(pw->pw_dir))
-		return NULL;
-	baselen = strlen(pw->pw_dir);
-	memcpy(buf, pw->pw_dir, baselen);
-	while ((1 < baselen) && (buf[baselen-1] == '/')) {
-		buf[baselen-1] = 0;
-		baselen--;
-	}
-	if (slash && slash[1]) {
-		len = strlen(slash);
-		if (sz <= baselen + len)
-			return NULL;
-		memcpy(buf + baselen, slash, len + 1);
-	}
-	return buf;
+	strbuf_add(&user_path, to_copy, strlen(to_copy));
+	return strbuf_detach(&user_path, NULL);
+return_null:
+	strbuf_release(&user_path);
+	return NULL;
 }
 
 /*
@@ -215,8 +304,18 @@ char *enter_repo(char *path, int strict)
 		if (PATH_MAX <= len)
 			return NULL;
 		if (path[0] == '~') {
-			if (!user_path(used_path, path, PATH_MAX))
+			char *newpath = expand_user_path(path);
+			if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
+				free(newpath);
 				return NULL;
+			}
+			/*
+			 * Copy back into the static buffer. A pity
+			 * since newpath was not bounded, but other
+			 * branches of the if are limited by PATH_MAX
+			 * anyway.
+			 */
+			strcpy(used_path, newpath); free(newpath);
 			strcpy(validated_path, path);
 			path = used_path;
 		}
@@ -242,11 +341,324 @@ char *enter_repo(char *path, int strict)
 		return NULL;
 
 	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
-	    validate_symref("HEAD") == 0) {
-		putenv("GIT_DIR=.");
+	    validate_headref("HEAD") == 0) {
+		set_git_dir(".");
 		check_repository_format();
 		return path;
 	}
 
 	return NULL;
 }
+
+int set_shared_perm(const char *path, int mode)
+{
+	struct stat st;
+	int tweak, shared, orig_mode;
+
+	if (!shared_repository) {
+		if (mode)
+			return chmod(path, mode & ~S_IFMT);
+		return 0;
+	}
+	if (!mode) {
+		if (lstat(path, &st) < 0)
+			return -1;
+		mode = st.st_mode;
+		orig_mode = mode;
+	} else
+		orig_mode = 0;
+	if (shared_repository < 0)
+		shared = -shared_repository;
+	else
+		shared = shared_repository;
+	tweak = shared;
+
+	if (!(mode & S_IWUSR))
+		tweak &= ~0222;
+	if (mode & S_IXUSR)
+		/* Copy read bits to execute bits */
+		tweak |= (tweak & 0444) >> 2;
+	if (shared_repository < 0)
+		mode = (mode & ~0777) | tweak;
+	else
+		mode |= tweak;
+
+	if (S_ISDIR(mode)) {
+		/* Copy read bits to execute bits */
+		mode |= (shared & 0444) >> 2;
+		mode |= FORCE_DIR_SET_GID;
+	}
+
+	if (((shared_repository < 0
+	      ? (orig_mode & (FORCE_DIR_SET_GID | 0777))
+	      : (orig_mode & mode)) != mode) &&
+	    chmod(path, (mode & ~S_IFMT)) < 0)
+		return -2;
+	return 0;
+}
+
+const char *relative_path(const char *abs, const char *base)
+{
+	static char buf[PATH_MAX + 1];
+	int i = 0, j = 0;
+
+	if (!base || !base[0])
+		return abs;
+	while (base[i]) {
+		if (is_dir_sep(base[i])) {
+			if (!is_dir_sep(abs[j]))
+				return abs;
+			while (is_dir_sep(base[i]))
+				i++;
+			while (is_dir_sep(abs[j]))
+				j++;
+			continue;
+		} else if (abs[j] != base[i]) {
+			return abs;
+		}
+		i++;
+		j++;
+	}
+	if (
+	    /* "/foo" is a prefix of "/foo" */
+	    abs[j] &&
+	    /* "/foo" is not a prefix of "/foobar" */
+	    !is_dir_sep(base[i-1]) && !is_dir_sep(abs[j])
+	   )
+		return abs;
+	while (is_dir_sep(abs[j]))
+		j++;
+	if (!abs[j])
+		strcpy(buf, ".");
+	else
+		strcpy(buf, abs + j);
+	return buf;
+}
+
+/*
+ * It is okay if dst == src, but they should not overlap otherwise.
+ *
+ * Performs the following normalizations on src, storing the result in dst:
+ * - Ensures that components are separated by '/' (Windows only)
+ * - Squashes sequences of '/'.
+ * - Removes "." components.
+ * - Removes ".." components, and the components the precede them.
+ * Returns failure (non-zero) if a ".." component appears as first path
+ * component anytime during the normalization. Otherwise, returns success (0).
+ *
+ * Note that this function is purely textual.  It does not follow symlinks,
+ * verify the existence of the path, or make any system calls.
+ */
+int normalize_path_copy(char *dst, const char *src)
+{
+	char *dst0;
+
+	if (has_dos_drive_prefix(src)) {
+		*dst++ = *src++;
+		*dst++ = *src++;
+	}
+	dst0 = dst;
+
+	if (is_dir_sep(*src)) {
+		*dst++ = '/';
+		while (is_dir_sep(*src))
+			src++;
+	}
+
+	for (;;) {
+		char c = *src;
+
+		/*
+		 * A path component that begins with . could be
+		 * special:
+		 * (1) "." and ends   -- ignore and terminate.
+		 * (2) "./"           -- ignore them, eat slash and continue.
+		 * (3) ".." and ends  -- strip one and terminate.
+		 * (4) "../"          -- strip one, eat slash and continue.
+		 */
+		if (c == '.') {
+			if (!src[1]) {
+				/* (1) */
+				src++;
+			} else if (is_dir_sep(src[1])) {
+				/* (2) */
+				src += 2;
+				while (is_dir_sep(*src))
+					src++;
+				continue;
+			} else if (src[1] == '.') {
+				if (!src[2]) {
+					/* (3) */
+					src += 2;
+					goto up_one;
+				} else if (is_dir_sep(src[2])) {
+					/* (4) */
+					src += 3;
+					while (is_dir_sep(*src))
+						src++;
+					goto up_one;
+				}
+			}
+		}
+
+		/* copy up to the next '/', and eat all '/' */
+		while ((c = *src++) != '\0' && !is_dir_sep(c))
+			*dst++ = c;
+		if (is_dir_sep(c)) {
+			*dst++ = '/';
+			while (is_dir_sep(c))
+				c = *src++;
+			src--;
+		} else if (!c)
+			break;
+		continue;
+
+	up_one:
+		/*
+		 * dst0..dst is prefix portion, and dst[-1] is '/';
+		 * go up one level.
+		 */
+		dst--;	/* go to trailing '/' */
+		if (dst <= dst0)
+			return -1;
+		/* Windows: dst[-1] cannot be backslash anymore */
+		while (dst0 < dst && dst[-1] != '/')
+			dst--;
+	}
+	*dst = '\0';
+	return 0;
+}
+
+/*
+ * path = Canonical absolute path
+ * prefix_list = Colon-separated list of absolute paths
+ *
+ * Determines, for each path in prefix_list, whether the "prefix" really
+ * is an ancestor directory of path.  Returns the length of the longest
+ * ancestor directory, excluding any trailing slashes, or -1 if no prefix
+ * is an ancestor.  (Note that this means 0 is returned if prefix_list is
+ * "/".) "/foo" is not considered an ancestor of "/foobar".  Directories
+ * are not considered to be their own ancestors.  path must be in a
+ * canonical form: empty components, or "." or ".." components are not
+ * allowed.  prefix_list may be null, which is like "".
+ */
+int longest_ancestor_length(const char *path, const char *prefix_list)
+{
+	char buf[PATH_MAX+1];
+	const char *ceil, *colon;
+	int len, max_len = -1;
+
+	if (prefix_list == NULL || !strcmp(path, "/"))
+		return -1;
+
+	for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
+		for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
+		len = colon - ceil;
+		if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
+			continue;
+		strlcpy(buf, ceil, len+1);
+		if (normalize_path_copy(buf, buf) < 0)
+			continue;
+		len = strlen(buf);
+		if (len > 0 && buf[len-1] == '/')
+			buf[--len] = '\0';
+
+		if (!strncmp(path, buf, len) &&
+		    path[len] == '/' &&
+		    len > max_len) {
+			max_len = len;
+		}
+	}
+
+	return max_len;
+}
+
+/* strip arbitrary amount of directory separators at end of path */
+static inline int chomp_trailing_dir_sep(const char *path, int len)
+{
+	while (len && is_dir_sep(path[len - 1]))
+		len--;
+	return len;
+}
+
+/*
+ * If path ends with suffix (complete path components), returns the
+ * part before suffix (sans trailing directory separators).
+ * Otherwise returns NULL.
+ */
+char *strip_path_suffix(const char *path, const char *suffix)
+{
+	int path_len = strlen(path), suffix_len = strlen(suffix);
+
+	while (suffix_len) {
+		if (!path_len)
+			return NULL;
+
+		if (is_dir_sep(path[path_len - 1])) {
+			if (!is_dir_sep(suffix[suffix_len - 1]))
+				return NULL;
+			path_len = chomp_trailing_dir_sep(path, path_len);
+			suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
+		}
+		else if (path[--path_len] != suffix[--suffix_len])
+			return NULL;
+	}
+
+	if (path_len && !is_dir_sep(path[path_len - 1]))
+		return NULL;
+	return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
+}
+
+int daemon_avoid_alias(const char *p)
+{
+	int sl, ndot;
+
+	/*
+	 * This resurrects the belts and suspenders paranoia check by HPA
+	 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
+	 * does not do getcwd() based path canonicalization.
+	 *
+	 * sl becomes true immediately after seeing '/' and continues to
+	 * be true as long as dots continue after that without intervening
+	 * non-dot character.
+	 */
+	if (!p || (*p != '/' && *p != '~'))
+		return -1;
+	sl = 1; ndot = 0;
+	p++;
+
+	while (1) {
+		char ch = *p++;
+		if (sl) {
+			if (ch == '.')
+				ndot++;
+			else if (ch == '/') {
+				if (ndot < 3)
+					/* reject //, /./ and /../ */
+					return -1;
+				ndot = 0;
+			}
+			else if (ch == 0) {
+				if (0 < ndot && ndot < 3)
+					/* reject /.$ and /..$ */
+					return -1;
+				return 0;
+			}
+			else
+				sl = ndot = 0;
+		}
+		else if (ch == 0)
+			return 0;
+		else if (ch == '/') {
+			sl = 1;
+			ndot = 0;
+		}
+	}
+}
+
+int offset_1st_component(const char *path)
+{
+	if (has_dos_drive_prefix(path))
+		return 2 + is_dir_sep(path[2]);
+	return is_dir_sep(path[0]);
+}