log_ref_setup(): improve robustness against races

[thirdparty/git.git] / refs / files-backend.c

diff --git a/refs/files-backend.c b/refs/files-backend.c
index c8f6d82e6d87307ac727d6e546910db1dc983df9..27d4fd3f9603e81eeefc0158a58f2103d642c7d7 100644 (file)
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2710,6 +2710,14 @@ static int commit_ref(struct ref_lock *lock)
        return 0;
 }
 
+static int open_or_create_logfile(const char *path, void *cb)
+{
+       int *fd = cb;
+
+       *fd = open(path, O_APPEND | O_WRONLY | O_CREAT, 0666);
+       return (*fd < 0) ? -1 : 0;
+}
+
 /*
  * Create a reflog for a ref.  If force_create = 0, the reflog will
  * only be created for certain refs (those for which
@@ -2723,31 +2731,18 @@ static int log_ref_setup(const char *refname, struct strbuf *logfile, struct str
        strbuf_git_path(logfile, "logs/%s", refname);
 
        if (force_create || should_autocreate_reflog(refname)) {
-               if (safe_create_leading_directories(logfile->buf) < 0) {
-                       strbuf_addf(err, "unable to create directory for '%s': "
-                                   "%s", logfile->buf, strerror(errno));
-                       return -1;
-               }
-               logfd = open(logfile->buf, O_APPEND | O_WRONLY | O_CREAT, 0666);
-               if (logfd < 0) {
-                       if (errno == EISDIR) {
-                               /*
-                                * The directory that is in the way might be
-                                * empty. Try to remove it.
-                                */
-                               if (remove_empty_directories(logfile)) {
-                                       strbuf_addf(err, "there are still logs under "
-                                                   "'%s'", logfile->buf);
-                                       return -1;
-                               }
-                               logfd = open(logfile->buf, O_APPEND | O_WRONLY | O_CREAT, 0666);
-                       }
-
-                       if (logfd < 0) {
+               if (raceproof_create_file(logfile->buf, open_or_create_logfile, &logfd)) {
+                       if (errno == ENOENT)
+                               strbuf_addf(err, "unable to create directory for '%s': "
+                                           "%s", logfile->buf, strerror(errno));
+                       else if (errno == EISDIR)
+                               strbuf_addf(err, "there are still logs under '%s'",
+                                           logfile->buf);
+                       else
                                strbuf_addf(err, "unable to append to '%s': %s",
                                            logfile->buf, strerror(errno));
-                               return -1;
-                       }
+
+                       return -1;
                }
        } else {
                logfd = open(logfile->buf, O_APPEND | O_WRONLY, 0666);