lockfile: change lock_file::filename into a strbuf

diff --git a/lockfile.c b/lockfile.c
index 1dd118f5566b9f29c840e528b020383964abe87e..85c8648c51ebff7f47da1763e77ad1cddac32a4e 100644 (file)
--- a/lockfile.c
+++ b/lockfile.c
@@ -47,9 +47,9 @@
  *   failed attempt to lock, or a failed close_lock_file()).  In this
  *   state:
  *   - active is unset
- *   - filename[0] == '\0' (usually, though there are transitory states
- *     in which this condition doesn't hold). Client code should *not*
- *     rely on this fact!
+ *   - filename is empty (usually, though there are transitory
+ *     states in which this condition doesn't hold). Client code should
+ *     *not* rely on the filename being empty in this state.
  *   - fd is -1
  *   - the object is left registered in the lock_file_list, and
  *     on_list is set.
@@ -170,13 +170,6 @@ static char *resolve_symlink(char *p, size_t s)
 /* Make sure errno contains a meaningful value on error */
 static int lock_file(struct lock_file *lk, const char *path, int flags)
 {
-       /*
-        * subtract LOCK_SUFFIX_LEN from size to make sure there's
-        * room for adding ".lock" for the lock file name:
-        */
-       static const size_t max_path_len = sizeof(lk->filename) -
-                                          LOCK_SUFFIX_LEN;
-
        if (!lock_file_list) {
                /* One-time initialization */
                sigchain_push_common(remove_lock_file_on_signal);
@@ -191,30 +184,32 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
                lk->fd = -1;
                lk->active = 0;
                lk->owner = 0;
-               lk->filename[0] = 0;
+               strbuf_init(&lk->filename, PATH_MAX);
                lk->next = lock_file_list;
                lock_file_list = lk;
                lk->on_list = 1;
+       } else if (lk->filename.len) {
+               /* This shouldn't happen, but better safe than sorry. */
+               die("BUG: lock_file(\"%s\") called with improperly-reset lock_file object",
+                   path);
        }
 
-       if (strlen(path) >= max_path_len) {
-               errno = ENAMETOOLONG;
-               return -1;
+       strbuf_addstr(&lk->filename, path);
+       if (!(flags & LOCK_NODEREF)) {
+               resolve_symlink(lk->filename.buf, lk->filename.alloc);
+               strbuf_setlen(&lk->filename, strlen(lk->filename.buf));
        }
-       strcpy(lk->filename, path);
-       if (!(flags & LOCK_NODEREF))
-               resolve_symlink(lk->filename, max_path_len);
-       strcat(lk->filename, LOCK_SUFFIX);
-       lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
+       strbuf_addstr(&lk->filename, LOCK_SUFFIX);
+       lk->fd = open(lk->filename.buf, O_RDWR | O_CREAT | O_EXCL, 0666);
        if (lk->fd < 0) {
-               lk->filename[0] = 0;
+               strbuf_reset(&lk->filename);
                return -1;
        }
        lk->owner = getpid();
        lk->active = 1;
-       if (adjust_shared_perm(lk->filename)) {
+       if (adjust_shared_perm(lk->filename.buf)) {
                int save_errno = errno;
-               error("cannot fix permission bits on %s", lk->filename);
+               error("cannot fix permission bits on %s", lk->filename.buf);
                rollback_lock_file(lk);
                errno = save_errno;
                return -1;
@@ -313,7 +308,7 @@ int reopen_lock_file(struct lock_file *lk)
                die(_("BUG: reopen a lockfile that is still open"));
        if (!lk->active)
                die(_("BUG: reopen a lockfile that has been committed"));
-       lk->fd = open(lk->filename, O_WRONLY);
+       lk->fd = open(lk->filename.buf, O_WRONLY);
        return lk->fd;
 }
 
@@ -329,9 +324,9 @@ int commit_lock_file(struct lock_file *lk)
                return -1;
 
        /* remove ".lock": */
-       strbuf_add(&result_file, lk->filename,
-                  strlen(lk->filename) - LOCK_SUFFIX_LEN);
-       err = rename(lk->filename, result_file.buf);
+       strbuf_add(&result_file, lk->filename.buf,
+                  lk->filename.len - LOCK_SUFFIX_LEN);
+       err = rename(lk->filename.buf, result_file.buf);
        strbuf_reset(&result_file);
        if (err) {
                int save_errno = errno;
@@ -341,7 +336,7 @@ int commit_lock_file(struct lock_file *lk)
        }
 
        lk->active = 0;
-       lk->filename[0] = 0;
+       strbuf_reset(&lk->filename);
        return 0;
 }
 
@@ -359,8 +354,8 @@ void rollback_lock_file(struct lock_file *lk)
                return;
 
        if (!close_lock_file(lk)) {
-               unlink_or_warn(lk->filename);
+               unlink_or_warn(lk->filename.buf);
                lk->active = 0;
-               lk->filename[0] = 0;
+               strbuf_reset(&lk->filename);
        }
 }