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-rw-r--r--src/lib/lockfile.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/src/lib/lockfile.c b/src/lib/lockfile.c
new file mode 100644
index 00000000..a93d5f17
--- /dev/null
+++ b/src/lib/lockfile.c
@@ -0,0 +1,170 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Lockfile for ouroboros system
+ *
+ * Dimitri Staessens <dimitri.staessens@intec.ugent.be>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <ouroboros/config.h>
+#include <ouroboros/lockfile.h>
+
+#define OUROBOROS_PREFIX "lockfile"
+
+#include <ouroboros/logs.h>
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#define LF_SIZE (sizeof(pid_t))
+
+struct lockfile {
+ pid_t * api;
+ int fd;
+};
+
+struct lockfile * lockfile_create() {
+ struct lockfile * lf = malloc(sizeof(*lf));
+ if (lf == NULL)
+ return NULL;
+
+ lf->fd = shm_open(LOCKFILE_NAME, O_CREAT | O_EXCL | O_RDWR, 0666);
+ if (lf->fd == -1) {
+ LOG_DBGF("Could not create lock file.");
+ free(lf);
+ return NULL;
+ }
+
+ if (fchmod(lf->fd, 0666)) {
+ LOG_DBGF("Failed to chmod lockfile.");
+ free(lf);
+ return NULL;
+ }
+
+ if (lseek(lf->fd, LF_SIZE - 1, SEEK_SET) < 0) {
+ LOG_DBGF("Failed to extend lockfile.");
+ free(lf);
+ return NULL;
+ }
+
+ if (write(lf->fd, "", 1) != 1) {
+ LOG_DBGF("Failed to finalise lockfile.");
+ free(lf);
+ return NULL;
+ }
+
+ lf->api = mmap(NULL,
+ LF_SIZE, PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ lf->fd,
+ 0);
+
+ if (lf->api == MAP_FAILED) {
+ LOG_DBGF("Failed to map lockfile.");
+
+ if (shm_unlink(LOCKFILE_NAME) == -1)
+ LOG_DBGF("Failed to remove invalid lockfile.");
+
+ free(lf);
+ return NULL;
+ }
+
+ *lf->api = getpid();
+
+ return lf;
+}
+
+struct lockfile * lockfile_open() {
+ struct lockfile * lf = malloc(sizeof(*lf));
+ if (lf == NULL)
+ return NULL;
+
+ lf->fd = shm_open(LOCKFILE_NAME, O_RDWR, 0666);
+ if (lf->fd == -1) {
+ LOG_DBGF("Could not open lock file.");
+ free(lf);
+ return NULL;
+ }
+
+ lf->api = mmap(NULL,
+ LF_SIZE, PROT_READ | PROT_WRITE,
+ MAP_SHARED,
+ lf->fd,
+ 0);
+
+ if (lf->api == MAP_FAILED) {
+ LOG_DBGF("Failed to map lockfile.");
+
+ if (shm_unlink(LOCKFILE_NAME) == -1)
+ LOG_DBGF("Failed to remove invalid lockfile.");
+
+ free(lf);
+ return NULL;
+ }
+
+ return lf;
+}
+
+void lockfile_close(struct lockfile * lf)
+{
+ if (lf == NULL) {
+ LOG_DBGF("Bogus input. Bugging out.");
+ return;
+ }
+
+ if (close(lf->fd) < 0)
+ LOG_DBGF("Couldn't close lockfile.");
+
+ if (munmap(lf->api, LF_SIZE) == -1)
+ LOG_DBGF("Couldn't unmap lockfile.");
+
+ free(lf);
+}
+
+void lockfile_destroy(struct lockfile * lf)
+{
+ if (lf == NULL) {
+ LOG_DBGF("Bogus input. Bugging out.");
+ return;
+ }
+
+ if (getpid() != *lf->api && kill(*lf->api, 0) == 0) {
+ LOG_DBGF("Only IRMd can destroy %s.", LOCKFILE_NAME);
+ return;
+ }
+
+ if (close(lf->fd) < 0)
+ LOG_DBGF("Couldn't close lockfile.");
+
+ if (munmap(lf->api, LF_SIZE) == -1)
+ LOG_DBGF("Couldn't unmap lockfile.");
+
+ if (shm_unlink(LOCKFILE_NAME) == -1)
+ LOG_DBGF("Failed to remove lockfile.");
+
+ free(lf);
+}
+
+pid_t lockfile_owner(struct lockfile * lf)
+{
+ return *lf->api;
+}