mirror of
https://github.com/clearlinux/swupd-client.git
synced 2026-09-08 06:31:50 +00:00
Matthew Johnson
aef0cc4490
Fixes #357 Add free_string() function to insure code is consistently resetting pointers to NULL after resetting dynamic memory. Use this helper everywhere strings are being freed. Signed-off-by: Matthew Johnson <matthew.johnson@intel.com>
96 lines
2.5 KiB
C
96 lines
2.5 KiB
C
/*
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* Software Updater - client side
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*
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* Copyright © 2012-2016 Intel Corporation.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2 or later of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* Authors:
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* Arjan van de Ven <arjan@linux.intel.com>
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* Tim Pepper <timothy.c.pepper@linux.intel.com>
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* Eric Lapuyade <eric.lapuyade@intel.com>
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* Jim Kukunas <james.t.kukunas@linux.intel.com>
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*
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*/
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/inotify.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "config.h"
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#include "swupd.h"
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/* Try to get a write lock region on the lock file. Returns:
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* >= 0 an fcntl region lock'd fd or exits with a positive error
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* code and a recommended course of action for user.
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*/
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int p_lockfile(void)
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{
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int lock_fd, ret;
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pid_t pid = getpid();
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struct flock fl = {
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.l_type = F_WRLCK,
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.l_whence = SEEK_SET,
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.l_start = 0,
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.l_len = 0,
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.l_pid = pid,
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};
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char *lockfile;
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string_or_die(&lockfile, "%s/swupd_lock", state_dir);
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/* open lock file */
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lock_fd = open(lockfile, O_RDWR | O_CREAT | O_CLOEXEC, 0600);
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if (lock_fd < 0) {
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fprintf(stderr, "Error: failed to open %s: %s\n", lockfile, strerror(errno));
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free_string(&lockfile);
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return -1;
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}
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free_string(&lockfile);
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/* try to get an advisory region lock for the file */
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ret = fcntl(lock_fd, F_SETLK, &fl);
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if (ret == -1) {
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if ((errno == EAGAIN) || (errno == EACCES)) {
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ret = -EAGAIN;
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}
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fprintf(stderr, "Error: cannot acquire lock file. Another swupd process is already running.\n");
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close(lock_fd);
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return ret;
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} else {
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/* speculatively dump our pid in the file,
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* that may be useful for debug */
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ret = ftruncate(lock_fd, 0);
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ret = write(lock_fd, &pid, sizeof(pid));
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/* our lock_fd represents the lock */
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return lock_fd;
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}
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}
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/* closes lock fd and must not unlink lock file (else race allowed) */
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void v_lockfile(int fd)
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{
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close(fd);
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}
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