Merge branch 'mh/lockfile-stdio'

* mh/lockfile-stdio:
commit_packed_refs(): reimplement using fdopen_lock_file()
dump_marks(): reimplement using fdopen_lock_file()
fdopen_lock_file(): access a lockfile using stdio

diff --combined lockfile.c
index 7bfec4b773bc710b474677b808c4bdacf53af91b,e0460275e1904e12728840102d0a51e98008eef9..d098adebf1454ea9c9204c9dd2fda4d51b63a1e5
--- 1/lockfile.c
--- 2/lockfile.c
+++ b/lockfile.c
@@@ -7,20 -7,29 +7,29 @@@
  
  static struct lock_file *volatile lock_file_list;
  
- static void remove_lock_files(void)
+ static void remove_lock_files(int skip_fclose)
  {
        pid_t me = getpid();
  
        while (lock_file_list) {
-               if (lock_file_list->owner == me)
+               if (lock_file_list->owner == me) {
+                       /* fclose() is not safe to call in a signal handler */
+                       if (skip_fclose)
+                               lock_file_list->fp = NULL;
                        rollback_lock_file(lock_file_list);
+               }
                lock_file_list = lock_file_list->next;
        }
  }
  
+ static void remove_lock_files_on_exit(void)
+ {
+       remove_lock_files(0);
+ }
+ 
  static void remove_lock_files_on_signal(int signo)
  {
-       remove_lock_files();
+       remove_lock_files(1);
        sigchain_pop(signo);
        raise(signo);
  }
@@@ -97,7 -106,7 +106,7 @@@ static int lock_file(struct lock_file *
        if (!lock_file_list) {
                /* One-time initialization */
                sigchain_push_common(remove_lock_files_on_signal);
-               atexit(remove_lock_files);
+               atexit(remove_lock_files_on_exit);
        }
  
        if (lk->active)
@@@ -106,6 -115,7 +115,7 @@@
        if (!lk->on_list) {
                /* Initialize *lk and add it to lock_file_list: */
                lk->fd = -1;
+               lk->fp = NULL;
                lk->active = 0;
                lk->owner = 0;
                strbuf_init(&lk->filename, pathlen + LOCK_SUFFIX_LEN);
@@@ -207,16 -217,24 +217,27 @@@ int hold_lock_file_for_append(struct lo
  
                if (flags & LOCK_DIE_ON_ERROR)
                        exit(128);
 +              close(orig_fd);
                rollback_lock_file(lk);
                errno = save_errno;
                return -1;
 +      } else {
 +              close(orig_fd);
        }
        return fd;
  }
  
+ FILE *fdopen_lock_file(struct lock_file *lk, const char *mode)
+ {
+       if (!lk->active)
+               die("BUG: fdopen_lock_file() called for unlocked object");
+       if (lk->fp)
+               die("BUG: fdopen_lock_file() called twice for file '%s'", lk->filename.buf);
+ 
+       lk->fp = fdopen(lk->fd, mode);
+       return lk->fp;
+ }
+ 
  char *get_locked_file_path(struct lock_file *lk)
  {
        if (!lk->active)
@@@ -229,17 -247,32 +250,32 @@@
  int close_lock_file(struct lock_file *lk)
  {
        int fd = lk->fd;
+       FILE *fp = lk->fp;
+       int err;
  
        if (fd < 0)
                return 0;
  
        lk->fd = -1;
-       if (close(fd)) {
+       if (fp) {
+               lk->fp = NULL;
+ 
+               /*
+                * Note: no short-circuiting here; we want to fclose()
+                * in any case!
+                */
+               err = ferror(fp) | fclose(fp);
+       } else {
+               err = close(fd);
+       }
+ 
+       if (err) {
                int save_errno = errno;
                rollback_lock_file(lk);
                errno = save_errno;
                return -1;
        }
+ 
        return 0;
  }