1 files changed, 100 insertions, 22 deletions

diff --git a/setup.c b/setup.c
index 5432a31b62..0a22f8bd1d 100644
--- a/setup.c
+++ b/setup.c
@@ -6,6 +6,70 @@ static int inside_git_dir = -1;
 static int inside_work_tree = -1;
 
 /*
+ * The input parameter must contain an absolute path, and it must already be
+ * normalized.
+ *
+ * Find the part of an absolute path that lies inside the work tree by
+ * dereferencing symlinks outside the work tree, for example:
+ * /dir1/repo/dir2/file   (work tree is /dir1/repo)      -> dir2/file
+ * /dir/file              (work tree is /)               -> dir/file
+ * /dir/symlink1/symlink2 (symlink1 points to work tree) -> symlink2
+ * /dir/repolink/file     (repolink points to /dir/repo) -> file
+ * /dir/repo              (exactly equal to work tree)   -> (empty string)
+ */
+static int abspath_part_inside_repo(char *path)
+{
+	size_t len;
+	size_t wtlen;
+	char *path0;
+	int off;
+	const char *work_tree = get_git_work_tree();
+
+	if (!work_tree)
+		return -1;
+	wtlen = strlen(work_tree);
+	len = strlen(path);
+	off = offset_1st_component(path);
+
+	/* check if work tree is already the prefix */
+	if (wtlen <= len && !strncmp(path, work_tree, wtlen)) {
+		if (path[wtlen] == '/') {
+			memmove(path, path + wtlen + 1, len - wtlen);
+			return 0;
+		} else if (path[wtlen - 1] == '/' || path[wtlen] == '\0') {
+			/* work tree is the root, or the whole path */
+			memmove(path, path + wtlen, len - wtlen + 1);
+			return 0;
+		}
+		/* work tree might match beginning of a symlink to work tree */
+		off = wtlen;
+	}
+	path0 = path;
+	path += off;
+
+	/* check each '/'-terminated level */
+	while (*path) {
+		path++;
+		if (*path == '/') {
+			*path = '\0';
+			if (strcmp(real_path(path0), work_tree) == 0) {
+				memmove(path0, path + 1, len - (path - path0));
+				return 0;
+			}
+			*path = '/';
+		}
+	}
+
+	/* check whole path */
+	if (strcmp(real_path(path0), work_tree) == 0) {
+		*path0 = '\0';
+		return 0;
+	}
+
+	return -1;
+}
+
+/*
  * Normalize "path", prepending the "prefix" for relative paths. If
  * remaining_prefix is not NULL, return the actual prefix still
  * remains in the path. For example, prefix = sub1/sub2/ and path is
@@ -22,11 +86,17 @@ char *prefix_path_gently(const char *prefix, int len,
 	const char *orig = path;
 	char *sanitized;
 	if (is_absolute_path(orig)) {
-		const char *temp = real_path(path);
-		sanitized = xmalloc(len + strlen(temp) + 1);
-		strcpy(sanitized, temp);
+		sanitized = xmalloc(strlen(path) + 1);
 		if (remaining_prefix)
 			*remaining_prefix = 0;
+		if (normalize_path_copy_len(sanitized, path, remaining_prefix)) {
+			free(sanitized);
+			return NULL;
+		}
+		if (abspath_part_inside_repo(sanitized)) {
+			free(sanitized);
+			return NULL;
+		}
 	} else {
 		sanitized = xmalloc(len + strlen(path) + 1);
 		if (len)
@@ -34,26 +104,10 @@ char *prefix_path_gently(const char *prefix, int len,
 		strcpy(sanitized + len, path);
 		if (remaining_prefix)
 			*remaining_prefix = len;
-	}
-	if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix))
-		goto error_out;
-	if (is_absolute_path(orig)) {
-		size_t root_len, len, total;
-		const char *work_tree = get_git_work_tree();
-		if (!work_tree)
-			goto error_out;
-		len = strlen(work_tree);
-		root_len = offset_1st_component(work_tree);
-		total = strlen(sanitized) + 1;
-		if (strncmp(sanitized, work_tree, len) ||
-		    (len > root_len && sanitized[len] != '\0' && sanitized[len] != '/')) {
-		error_out:
+		if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {
 			free(sanitized);
 			return NULL;
 		}
-		if (sanitized[len] == '/')
-			len++;
-		memmove(sanitized, sanitized + len, total - len);
 	}
 	return sanitized;
 }
@@ -82,7 +136,7 @@ int check_filename(const char *prefix, const char *arg)
 	const char *name;
 	struct stat st;
 
-	if (!prefixcmp(arg, ":/")) {
+	if (starts_with(arg, ":/")) {
 		if (arg[2] == '\0') /* ":/" is root dir, always exists */
 			return 1;
 		name = arg + 2;
@@ -304,7 +358,7 @@ const char *read_gitfile(const char *path)
 	if (len != st.st_size)
 		die("Error reading %s", path);
 	buf[len] = '\0';
-	if (prefixcmp(buf, "gitdir: "))
+	if (!starts_with(buf, "gitdir: "))
 		die("Invalid gitfile format: %s", path);
 	while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 		len--;
@@ -787,3 +841,27 @@ void sanitize_stdfds(void)
 	if (fd > 2)
 		close(fd);
 }
+
+int daemonize(void)
+{
+#ifdef NO_POSIX_GOODIES
+	errno = ENOSYS;
+	return -1;
+#else
+	switch (fork()) {
+		case 0:
+			break;
+		case -1:
+			die_errno("fork failed");
+		default:
+			exit(0);
+	}
+	if (setsid() == -1)
+		die_errno("setsid failed");
+	close(0);
+	close(1);
+	close(2);
+	sanitize_stdfds();
+	return 0;
+#endif
+}