unix-sockets: use strbuf_getcwd()

Instead of using a PATH_MAX-sized buffer, which can be too small on some
file systems, use strbuf_getcwd(), which handles any path getcwd()
returns.  Also preserve the errno set by strbuf_getcwd() instead of
setting it to ENAMETOOLONG; that way a more appropriate error message
can be shown based on the actual reason for failing.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/unix-socket.c b/unix-socket.c
index 01f119f9700791ddc59a81cdc80fd365e678622a..943a94734a25a2b3e0c7e33b89e16b41a11ab520 100644 (file)
--- a/unix-socket.c
+++ b/unix-socket.c
@@ -18,12 +18,12 @@ static int chdir_len(const char *orig, int len)
 }
 
 struct unix_sockaddr_context {
-       char orig_dir[PATH_MAX];
+       char *orig_dir;
 };
 
 static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
 {
-       if (!ctx->orig_dir[0])
+       if (!ctx->orig_dir)
                return;
        /*
         * If we fail, we can't just return an error, since we have
@@ -32,6 +32,7 @@ static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
         */
        if (chdir(ctx->orig_dir) < 0)
                die("unable to restore original working directory");
+       free(ctx->orig_dir);
 }
 
 static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
@@ -39,10 +40,11 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
 {
        int size = strlen(path) + 1;
 
-       ctx->orig_dir[0] = '\0';
+       ctx->orig_dir = NULL;
        if (size > sizeof(sa->sun_path)) {
                const char *slash = find_last_dir_sep(path);
                const char *dir;
+               struct strbuf cwd = STRBUF_INIT;
 
                if (!slash) {
                        errno = ENAMETOOLONG;
@@ -56,11 +58,9 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
                        errno = ENAMETOOLONG;
                        return -1;
                }
-
-               if (!getcwd(ctx->orig_dir, sizeof(ctx->orig_dir))) {
-                       errno = ENAMETOOLONG;
+               if (strbuf_getcwd(&cwd))
                        return -1;
-               }
+               ctx->orig_dir = strbuf_detach(&cwd, NULL);
                if (chdir_len(dir, slash - dir) < 0)
                        return -1;
        }