lockfile.c: store absolute path

Locked paths can be saved in a linked list so that if something wrong
happens, *.lock are removed. For relative paths, this works fine if we
keep cwd the same, which is true 99% of time except:

- update-index and read-tree hold the lock on $GIT_DIR/index really
early, then later on may call setup_work_tree() to move cwd.

- Suppose a lock is being held (e.g. by "git add") then somewhere
down the line, somebody calls real_path (e.g. "link_alt_odb_entry"),
which temporarily moves cwd away and back.

During that time when cwd is moved (either permanently or temporarily)
and we decide to die(), attempts to remove relative *.lock will fail,
and the next operation will complain that some files are still locked.

Avoid this case by turning relative paths to absolute before storing
the path in "filename" field.

Reported-by: Yue Lin Ho <yuelinho777@gmail.com>
Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Adapted-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/lockfile.c b/lockfile.c
index 4f16ee78ce3dbc263a762a8800dfe9ddfcfaecd5..988927775169487df7677a17465b512a567488dd 100644 (file)
--- a/lockfile.c
+++ b/lockfile.c
@@ -128,9 +128,17 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
                    path);
        }
 
-       strbuf_add(&lk->filename, path, pathlen);
-       if (!(flags & LOCK_NO_DEREF))
-               resolve_symlink(&lk->filename);
+       if (flags & LOCK_NO_DEREF) {
+               strbuf_add_absolute_path(&lk->filename, path);
+       } else {
+               struct strbuf resolved_path = STRBUF_INIT;
+
+               strbuf_add(&resolved_path, path, pathlen);
+               resolve_symlink(&resolved_path);
+               strbuf_add_absolute_path(&lk->filename, resolved_path.buf);
+               strbuf_release(&resolved_path);
+       }
+
        strbuf_addstr(&lk->filename, LOCK_SUFFIX);
        lk->fd = open(lk->filename.buf, O_RDWR | O_CREAT | O_EXCL, 0666);
        if (lk->fd < 0) {

diff --git a/t/t2107-update-index-basic.sh b/t/t2107-update-index-basic.sh
index 1bafb9098c7fae33969e9231fbdee1c0370830a1..dfe02f48183ad77a93d72c0f5e952380b63a9229 100755 (executable)
--- a/t/t2107-update-index-basic.sh
+++ b/t/t2107-update-index-basic.sh
@@ -65,4 +65,19 @@ test_expect_success '--cacheinfo mode,sha1,path (new syntax)' '
        test_cmp expect actual
 '
 
+test_expect_success '.lock files cleaned up' '
+       mkdir cleanup &&
+       (
+       cd cleanup &&
+       mkdir worktree &&
+       git init repo &&
+       cd repo &&
+       git config core.worktree ../../worktree &&
+       # --refresh triggers late setup_work_tree,
+       # active_cache_changed is zero, rollback_lock_file fails
+       git update-index --refresh &&
+       ! test -f .git/index.lock
+       )
+'
+
 test_done