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-rw-r--r--lockfile.c261
1 files changed, 16 insertions, 245 deletions
diff --git a/lockfile.c b/lockfile.c
index 3904803..e1d68f7 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -2,90 +2,8 @@
* Copyright (c) 2005, Junio C Hamano
*/
-/*
- * State diagram and cleanup
- * -------------------------
- *
- * 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.
- *
- * 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 `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
- * - `fp` holds a pointer to an open `FILE` object if and only if
- * `fdopen_lock_file()` has been called on the object
- * - `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.
- *
- * A lockfile is owned by the process that created it. The `lock_file`
- * has an `owner` field that records the owner's PID. This field is
- * used to prevent a forked process from closing a lockfile created by
- * its parent.
- */
-
#include "cache.h"
#include "lockfile.h"
-#include "sigchain.h"
-
-static struct lock_file *volatile lock_file_list;
-
-static void remove_lock_files(int skip_fclose)
-{
- pid_t me = getpid();
-
- while (lock_file_list) {
- 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(1);
- sigchain_pop(signo);
- raise(signo);
-}
/*
* path = absolute or relative path name
@@ -154,60 +72,17 @@ static void resolve_symlink(struct strbuf *path)
/* Make sure errno contains a meaningful value on error */
static int lock_file(struct lock_file *lk, const char *path, int flags)
{
- size_t pathlen = strlen(path);
-
- if (!lock_file_list) {
- /* One-time initialization */
- sigchain_push_common(remove_lock_files_on_signal);
- atexit(remove_lock_files_on_exit);
- }
+ int fd;
+ struct strbuf filename = STRBUF_INIT;
- if (lk->active)
- die("BUG: cannot lock_file(\"%s\") using active struct lock_file",
- path);
- 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);
- lk->next = lock_file_list;
- lock_file_list = lk;
- lk->on_list = 1;
- } else if (lk->filename.len) {
- /* This shouldn't happen, but better safe than sorry. */
- die("BUG: lock_file(\"%s\") called with improperly-reset lock_file object",
- path);
- }
+ strbuf_addstr(&filename, path);
+ if (!(flags & LOCK_NO_DEREF))
+ resolve_symlink(&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) {
- strbuf_reset(&lk->filename);
- return -1;
- }
- lk->owner = getpid();
- lk->active = 1;
- if (adjust_shared_perm(lk->filename.buf)) {
- int save_errno = errno;
- error("cannot fix permission bits on %s", lk->filename.buf);
- rollback_lock_file(lk);
- errno = save_errno;
- return -1;
- }
- return lk->fd;
+ strbuf_addstr(&filename, LOCK_SUFFIX);
+ fd = create_tempfile(&lk->tempfile, filename.buf);
+ strbuf_release(&filename);
+ return fd;
}
static int sleep_microseconds(long us)
@@ -353,109 +228,17 @@ int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
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;
-}
-
-const char *get_lock_file_path(struct lock_file *lk)
-{
- if (!lk->active)
- die("BUG: get_lock_file_path() called for unlocked object");
- return lk->filename.buf;
-}
-
-int get_lock_file_fd(struct lock_file *lk)
-{
- if (!lk->active)
- die("BUG: get_lock_file_fd() called for unlocked object");
- return lk->fd;
-}
-
-FILE *get_lock_file_fp(struct lock_file *lk)
-{
- if (!lk->active)
- die("BUG: get_lock_file_fp() called for unlocked object");
- return lk->fp;
-}
-
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 ||
- strcmp(lk->filename.buf + lk->filename.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
+ struct strbuf ret = STRBUF_INIT;
+
+ strbuf_addstr(&ret, get_tempfile_path(&lk->tempfile));
+ if (ret.len <= LOCK_SUFFIX_LEN ||
+ strcmp(ret.buf + ret.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
die("BUG: get_locked_file_path() called for malformed lock object");
/* remove ".lock": */
- return xmemdupz(lk->filename.buf, lk->filename.len - LOCK_SUFFIX_LEN);
-}
-
-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 (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;
-}
-
-int reopen_lock_file(struct lock_file *lk)
-{
- if (0 <= lk->fd)
- die(_("BUG: reopen a lockfile that is still open"));
- if (!lk->active)
- die(_("BUG: reopen a lockfile that has been committed"));
- lk->fd = open(lk->filename.buf, O_WRONLY);
- return lk->fd;
-}
-
-int commit_lock_file_to(struct lock_file *lk, const char *path)
-{
- if (!lk->active)
- die("BUG: attempt to commit unlocked object to \"%s\"", path);
-
- if (close_lock_file(lk))
- return -1;
-
- if (rename(lk->filename.buf, path)) {
- int save_errno = errno;
- rollback_lock_file(lk);
- errno = save_errno;
- return -1;
- }
-
- lk->active = 0;
- strbuf_reset(&lk->filename);
- return 0;
+ strbuf_setlen(&ret, ret.len - LOCK_SUFFIX_LEN);
+ return strbuf_detach(&ret, NULL);
}
int commit_lock_file(struct lock_file *lk)
@@ -471,15 +254,3 @@ int commit_lock_file(struct lock_file *lk)
free(result_path);
return 0;
}
-
-void rollback_lock_file(struct lock_file *lk)
-{
- if (!lk->active)
- return;
-
- if (!close_lock_file(lk)) {
- unlink_or_warn(lk->filename.buf);
- lk->active = 0;
- strbuf_reset(&lk->filename);
- }
-}