#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) {
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);
}
static void trim_last_path_component(struct strbuf *path)
{
int i = path->len;
while (i && path->buf[i - 1] == '/')
i--;
while (i && path->buf[i - 1] != '/')
i--;
strbuf_setlen(path, i);
}
#define MAXDEPTH 5
static void resolve_symlink(struct strbuf *path)
{
int depth = MAXDEPTH;
static struct strbuf link = STRBUF_INIT;
while (depth--) {
if (strbuf_readlink(&link, path->buf, path->len) < 0)
break;
if (is_absolute_path(link.buf))
strbuf_reset(path);
else
trim_last_path_component(path);
strbuf_addbuf(path, &link);
}
strbuf_reset(&link);
}
static int lock_file(struct lock_file *lk, const char *path, int flags)
{
size_t pathlen = strlen(path);
if (!lock_file_list) {
sigchain_push_common(remove_lock_files_on_signal);
atexit(remove_lock_files_on_exit);
}
if (lk->active)
die("BUG: cannot lock_file(\"%s\") using active struct lock_file",
path);
if (!lk->on_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) {
die("BUG: lock_file(\"%s\") called with improperly-reset lock_file object",
path);
}
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;
}
void unable_to_lock_message(const char *path, int err, struct strbuf *buf)
{
if (err == EEXIST) {
strbuf_addf(buf, "Unable to create '%s.lock': %s.\n\n"
"If no other git process is currently running, this probably means a\n"
"git process crashed in this repository earlier. Make sure no other git\n"
"process is running and remove the file manually to continue.",
absolute_path(path), strerror(err));
} else
strbuf_addf(buf, "Unable to create '%s.lock': %s",
absolute_path(path), strerror(err));
}
NORETURN void unable_to_lock_die(const char *path, int err)
{
struct strbuf buf = STRBUF_INIT;
unable_to_lock_message(path, err, &buf);
die("%s", buf.buf);
}
int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
{
int fd = lock_file(lk, path, flags);
if (fd < 0 && (flags & LOCK_DIE_ON_ERROR))
unable_to_lock_die(path, errno);
return fd;
}
int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
{
int fd, orig_fd;
fd = lock_file(lk, path, flags);
if (fd < 0) {
if (flags & LOCK_DIE_ON_ERROR)
unable_to_lock_die(path, errno);
return fd;
}
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);
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);
close(orig_fd);
rollback_lock_file(lk);
errno = save_errno;
return -1;
} else {
close(orig_fd);
}
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;
}
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;
FILE *fp = lk->fp;
int err;
if (fd < 0)
return 0;
lk->fd = -1;
if (fp) {
lk->fp = NULL;
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;
}
int commit_lock_file(struct lock_file *lk)
{
static struct strbuf result_file = STRBUF_INIT;
int err;
if (!lk->active)
die("BUG: attempt to commit unlocked object");
if (lk->filename.len <= LOCK_SUFFIX_LEN ||
strcmp(lk->filename.buf + lk->filename.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
die("BUG: lockfile filename corrupt");
strbuf_add(&result_file, lk->filename.buf,
lk->filename.len - LOCK_SUFFIX_LEN);
err = commit_lock_file_to(lk, result_file.buf);
strbuf_reset(&result_file);
return err;
}
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);
}
}