Fix stale index.lock file removal using "atexit()".

Problem noted by Randy Dunlap.

diff --git a/read-tree.c b/read-tree.c
index 5784802..5c9d38b 100644 (file)
--- a/read-tree.c
+++ b/read-tree.c
@@ -63,6 +63,14 @@ static int read_tree(unsigned char *sha1, const char *base, int baselen)
        return 0;
 }
 
+static int remove_lock = 0;
+
+static void remove_lock_file(void)
+{
+       if (remove_lock)
+               unlink(".dircache/index.lock");
+}
+
 int main(int argc, char **argv)
 {
        int i, newfd;
@@ -71,35 +79,28 @@ int main(int argc, char **argv)
        newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
        if (newfd < 0)
                usage("unable to create new cachefile");
+       atexit(remove_lock_file);
+       remove_lock = 1;
 
        for (i = 1; i < argc; i++) {
                const char *arg = argv[i];
 
                /* "-m" stands for "merge" current directory cache */
                if (!strcmp(arg, "-m")) {
-                       if (active_cache) {
-                               fprintf(stderr, "read-tree: cannot merge old cache on top of new\n");
-                               goto out;
-                       }
-                       if (read_cache() < 0) {
-                               fprintf(stderr, "read-tree: corrupt directory cache\n");
-                               goto out;
-                       }
+                       if (active_cache)
+                               usage("read-tree: cannot merge old cache on top of new");
+                       if (read_cache() < 0)
+                               usage("read-tree: corrupt directory cache");
                        continue;
                }
-               if (get_sha1_hex(arg, sha1) < 0) {
-                       fprintf(stderr, "read-tree [-m] <sha1>\n");
-                       goto out;
-               }
-               if (read_tree(sha1, "", 0) < 0) {
-                       fprintf(stderr, "failed to unpack tree object %s\n", arg);
-                       goto out;
-               }
+               if (get_sha1_hex(arg, sha1) < 0)
+                       usage("read-tree [-m] <sha1>");
+               if (read_tree(sha1, "", 0) < 0)
+                       usage("failed to unpack tree object %s", arg);
        }
-       if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
-               return 0;
-
-out:
-       unlink(".dircache/index.lock");
-       exit(1);
+       if (write_cache(newfd, active_cache, active_nr) ||
+           rename(".dircache/index.lock", ".dircache/index"))
+               usage("unable to write new index file");
+       remove_lock = 0;
+       return 0;
 }

diff --git a/update-cache.c b/update-cache.c
index b39185a..ea956e4 100644 (file)
--- a/update-cache.c
+++ b/update-cache.c
@@ -230,22 +230,30 @@ inside:
        }
 }
 
+static int remove_lock = 0;
+
+static void remove_lock_file(void)
+{
+       if (remove_lock)
+               unlink(".dircache/index.lock");
+}
+
 int main(int argc, char **argv)
 {
        int i, newfd, entries;
        int allow_options = 1;
 
+       newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
+       if (newfd < 0)
+               usage("unable to create new cachefile");
+
+       atexit(remove_lock_file);
+       remove_lock = 1;
+
        entries = read_cache();
-       if (entries < 0) {
-               perror("cache corrupted");
-               return -1;
-       }
+       if (entries < 0)
+               usage("cache corrupted");
 
-       newfd = open(".dircache/index.lock", O_RDWR | O_CREAT | O_EXCL, 0600);
-       if (newfd < 0) {
-               perror("unable to create new cachefile");
-               return -1;
-       }
        for (i = 1 ; i < argc; i++) {
                char *path = argv[i];
 
@@ -272,14 +280,13 @@ int main(int argc, char **argv)
                        fprintf(stderr, "Ignoring path %s\n", argv[i]);
                        continue;
                }
-               if (add_file_to_cache(path)) {
-                       fprintf(stderr, "Unable to add %s to database\n", path);
-                       goto out;
-               }
+               if (add_file_to_cache(path))
+                       usage("Unable to add %s to database", path);
        }
-       if (!write_cache(newfd, active_cache, active_nr) && !rename(".dircache/index.lock", ".dircache/index"))
-               return 0;
-out:
-       unlink(".dircache/index.lock");
+       if (write_cache(newfd, active_cache, active_nr) ||
+           rename(".dircache/index.lock", ".dircache/index"))
+               usage("Unable to write new cachefile");
+
+       remove_lock = 0;
        return 0;
 }