* Copyright (c) 2005, Junio C Hamano
*/
#include "cache.h"
+#include "lockfile.h"
#include "sigchain.h"
-/*
- * File write-locks as used by Git.
- *
- * For an overview of how to use the lockfile API, please see
- *
- * Documentation/technical/api-lockfile.txt
- *
- * This module keeps track of all locked files in lock_file_list for
- * use at cleanup. This list and the lock_file objects that comprise
- * it must be kept in self-consistent states at all time, because the
- * program can be interrupted any time by a signal, in which case the
- * signal handler will walk through the list attempting to clean up
- * any open lock files.
- *
- * A lockfile is owned by the process that created it. The lock_file
- * object has an "owner" field that records its owner. This field is
- * used to prevent a forked process from closing a lockfile created by
- * its parent.
- *
- * The possible states of a lock_file object are as follows:
- *
- * - Uninitialized. In this state the object's on_list field must be
- * zero but the rest of its contents need not be initialized. As
- * soon as the object is used in any way, it is irrevocably
- * registered in the lock_file_list, and on_list is set.
- *
- * - Locked, lockfile open (after hold_lock_file_for_update(),
- * hold_lock_file_for_append(), or reopen_lock_file()). In this
- * state:
- * - the lockfile exists
- * - active is set
- * - filename holds the filename of the lockfile
- * - fd holds a file descriptor open for writing to the lockfile
- * - owner holds the PID of the process that locked the file
- *
- * - Locked, lockfile closed (after successful close_lock_file()).
- * Same as the previous state, except that the lockfile is closed
- * and fd is -1.
- *
- * - Unlocked (after commit_lock_file(), commit_lock_file_to(),
- * rollback_lock_file(), a failed attempt to lock, or a failed
- * close_lock_file()). In this state:
- * - active is unset
- * - 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.
- */
-
static struct lock_file *volatile lock_file_list;
static void remove_lock_files(void)
orig_fd = open(path, O_RDONLY);
if (orig_fd < 0) {
if (errno != ENOENT) {
+ int save_errno = errno;
+
if (flags & LOCK_DIE_ON_ERROR)
die("cannot open '%s' for copying", path);
rollback_lock_file(lk);
- return error("cannot open '%s' for copying", path);
+ error("cannot open '%s' for copying", path);
+ errno = save_errno;
+ return -1;
}
} else if (copy_fd(orig_fd, fd)) {
+ int save_errno = errno;
+
if (flags & LOCK_DIE_ON_ERROR)
exit(128);
rollback_lock_file(lk);
+ errno = save_errno;
return -1;
}
return fd;
}
+char *get_locked_file_path(struct lock_file *lk)
+{
+ if (!lk->active)
+ die("BUG: get_locked_file_path() called for unlocked object");
+ if (lk->filename.len <= LOCK_SUFFIX_LEN)
+ die("BUG: get_locked_file_path() called for malformed lock object");
+ return xmemdupz(lk->filename.buf, lk->filename.len - LOCK_SUFFIX_LEN);
+}
+
int close_lock_file(struct lock_file *lk)
{
int fd = lk->fd;
return err;
}
-int hold_locked_index(struct lock_file *lk, int die_on_error)
-{
- return hold_lock_file_for_update(lk, get_index_file(),
- die_on_error
- ? LOCK_DIE_ON_ERROR
- : 0);
-}
-
void rollback_lock_file(struct lock_file *lk)
{
if (!lk->active)