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/*
* Copyright (c) 2019 Stefan Sperling <stsp@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "got_compat.h"
#include <sys/stat.h>
#include <sys/queue.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include "got_error.h"
#include "got_path.h"
#include "got_lib_lockfile.h"
const struct got_error *
got_lockfile_lock(struct got_lockfile **lf, const char *path, int dir_fd)
{
const struct got_error *err = NULL;
int attempts = 5;
*lf = calloc(1, sizeof(**lf));
if (*lf == NULL)
return got_error_from_errno("calloc");
(*lf)->fd = -1;
(*lf)->locked_path = strdup(path);
if ((*lf)->locked_path == NULL) {
err = got_error_from_errno("strdup");
goto done;
}
if (asprintf(&(*lf)->path, "%s%s", path, GOT_LOCKFILE_SUFFIX) == -1) {
err = got_error_from_errno("asprintf");
goto done;
}
do {
if (dir_fd != -1) {
(*lf)->fd = openat(dir_fd, (*lf)->path,
O_RDWR | O_CREAT | O_EXCL | O_EXLOCK | O_CLOEXEC,
GOT_DEFAULT_FILE_MODE);
} else {
(*lf)->fd = open((*lf)->path,
O_RDWR | O_CREAT | O_EXCL | O_EXLOCK | O_CLOEXEC,
GOT_DEFAULT_FILE_MODE);
}
if ((*lf)->fd != -1)
break;
if (errno != EEXIST) {
err = got_error_from_errno2("open", (*lf)->path);
goto done;
}
sleep(1);
} while (--attempts > 0);
if ((*lf)->fd == -1) {
err = got_error_fmt(GOT_ERR_LOCKFILE_TIMEOUT,
"%s", (*lf)->path);
}
done:
if (err) {
got_lockfile_unlock(*lf, dir_fd);
*lf = NULL;
}
return err;
}
const struct got_error *
got_lockfile_unlock(struct got_lockfile *lf, int dir_fd)
{
const struct got_error *err = NULL;
if (dir_fd != -1) {
if (lf->path && lf->fd != -1 &&
unlinkat(dir_fd, lf->path, 0) != 0)
err = got_error_from_errno("unlinkat");
} else if (lf->path && lf->fd != -1 && unlink(lf->path) != 0)
err = got_error_from_errno("unlink");
if (lf->fd != -1 && close(lf->fd) == -1 && err == NULL)
err = got_error_from_errno("close");
free(lf->path);
free(lf->locked_path);
free(lf);
return err;
}
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