From: Daniel Barkalow Date: Thu, 17 Apr 2008 23:32:26 +0000 (-0400) Subject: Add a lockfile function to append to a file X-Git-Tag: v1.5.6-rc0~5^2~12 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=ea3cd5c7c63fadacd66c364ae4b8c6d01e5809b1;p=git.git Add a lockfile function to append to a file This takes care of copying the original contents into the replacement file after the lock is held, so that concurrent additions can't miss each other's changes. [jc: munged to drop mmap in favor of copy_file.] Signed-off-by: Daniel Barkalow Signed-off-by: Junio C Hamano --- diff --git a/cache.h b/cache.h index 5a28dddec..396eabf6e 100644 --- a/cache.h +++ b/cache.h @@ -391,6 +391,7 @@ struct lock_file { char filename[PATH_MAX]; }; extern int hold_lock_file_for_update(struct lock_file *, const char *path, int); +extern int hold_lock_file_for_append(struct lock_file *, const char *path, int); extern int commit_lock_file(struct lock_file *); extern int hold_locked_index(struct lock_file *, int); diff --git a/lockfile.c b/lockfile.c index 663f18f9c..e9e0095e9 100644 --- a/lockfile.c +++ b/lockfile.c @@ -160,6 +160,34 @@ int hold_lock_file_for_update(struct lock_file *lk, const char *path, int die_on return fd; } +int hold_lock_file_for_append(struct lock_file *lk, const char *path, int die_on_error) +{ + int fd, orig_fd; + + fd = lock_file(lk, path); + if (fd < 0) { + if (die_on_error) + die("unable to create '%s.lock': %s", path, strerror(errno)); + return fd; + } + + orig_fd = open(path, O_RDONLY); + if (orig_fd < 0) { + if (errno != ENOENT) { + if (die_on_error) + die("cannot open '%s' for copying", path); + close(fd); + return error("cannot open '%s' for copying", path); + } + } else if (copy_fd(orig_fd, fd)) { + if (die_on_error) + exit(128); + close(fd); + return -1; + } + return fd; +} + int close_lock_file(struct lock_file *lk) { int fd = lk->fd;