#include <netinet/in.h>
#include <stdlib.h>
#include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
#include "coverage.h"
#include "dynamic-string.h"
+#include "lockfile.h"
#include "ofpbuf.h"
#include "packets.h"
#include "svec.h"
static char *tmp_name;
/* Lock information. */
-static char *lock_name;
-static int lock_fd = -1;
+static struct lockfile *lockfile;
/* Flag to indicate whether local modifications have been made. */
static bool dirty;
int
cfg_set_file(const char *file_name)
{
- const char *slash;
+ char *lock_name;
int fd;
if (cfg_name) {
- assert(lock_fd < 0);
+ assert(!lockfile);
free(cfg_name);
- free(lock_name);
free(tmp_name);
- cfg_name = lock_name = tmp_name = NULL;
+ cfg_name = tmp_name = NULL;
}
/* Make sure that we can open this file for reading. */
* rename(tmp_name, cfg_name) will work. */
tmp_name = xasprintf("%s.~tmp~", file_name);
- /* Put the lock file in the same directory as cfg_name, but prefixed by
- * a dot so as not to garner administrator interest. */
- slash = strrchr(file_name, '/');
- if (slash) {
- lock_name = xasprintf("%.*s/.%s.~lock~",
- slash - file_name, file_name, slash + 1);
- } else {
- lock_name = xasprintf(".%s.~lock~", file_name);
- }
-
+ lock_name = lockfile_name(file_name);
VLOG_INFO("using \"%s\" as configuration file, \"%s\" as lock file",
file_name, lock_name);
+ free(lock_name);
+
return 0;
}
void
cfg_unlock(void)
{
- if (lock_fd != -1) {
- COVERAGE_INC(cfg_unlock);
- close(lock_fd);
- lock_fd = -1;
+ if (lockfile) {
+ lockfile_unlock(lockfile);
+ lockfile = NULL;
}
}
-static int
-open_lockfile(const char *name)
-{
- for (;;) {
- /* Try to open an existing lock file. */
- int fd = open(name, O_RDWR);
- if (fd >= 0) {
- return fd;
- } else if (errno != ENOENT) {
- VLOG_WARN("%s: failed to open lock file: %s",
- name, strerror(errno));
- return -errno;
- }
-
- /* Try to create a new lock file. */
- VLOG_INFO("%s: lock file does not exist, creating", name);
- fd = open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
- if (fd >= 0) {
- return fd;
- } else if (errno != EEXIST) {
- VLOG_WARN("%s: failed to create lock file: %s",
- name, strerror(errno));
- return -errno;
- }
-
- /* Someone else created the lock file. Try again. */
- }
-}
-
-static int
-try_lock(int fd, bool block)
-{
- struct flock l;
- memset(&l, 0, sizeof l);
- l.l_type = F_WRLCK;
- l.l_whence = SEEK_SET;
- l.l_start = 0;
- l.l_len = 0;
- return fcntl(fd, block ? F_SETLKW : F_SETLK, &l) == -1 ? errno : 0;
-}
-
/* Locks the configuration file against modification by other processes and
* re-reads it from disk.
*
int
cfg_lock(uint8_t *cookie, int timeout)
{
- long long int start;
- long long int elapsed = 0;
- int fd;
- uint8_t curr_cookie[CFG_COOKIE_LEN];
-
- assert(lock_fd < 0);
- COVERAGE_INC(cfg_lock);
-
- time_refresh();
- start = time_msec();
- for (;;) {
- int error;
-
- /* Open lock file. */
- fd = open_lockfile(lock_name);
- if (fd < 0) {
- return -fd;
- }
-
- /* Try to lock it. This will block (if 'timeout' > 0). */
- error = try_lock(fd, timeout > 0);
- time_refresh();
- elapsed = time_msec() - start;
- if (!error) {
- /* Success! */
- break;
- }
-
- /* Lock failed. Close the lock file and reopen it on the next
- * iteration, just in case someone deletes it underneath us (even
- * though that should not happen). */
- close(fd);
- if (error != EINTR) {
- /* Hard error, give up. */
- COVERAGE_INC(cfg_lock_error);
- VLOG_WARN("%s: failed to lock file "
- "(after %lld ms, with %d-ms timeout): %s",
- lock_name, elapsed, timeout, strerror(error));
- return error;
- }
+ int error;
- /* Probably, the periodic timer set up by time_init() woke up us. Just
- * check whether it's time to give up. */
- if (timeout != INT_MAX && elapsed >= timeout) {
- COVERAGE_INC(cfg_lock_timeout);
- VLOG_WARN("%s: giving up on lock file after %lld ms",
- lock_name, elapsed);
- return ETIMEDOUT;
- }
- COVERAGE_INC(cfg_lock_retry);
- }
- if (elapsed) {
- VLOG_WARN("%s: waited %lld ms for lock file", lock_name, elapsed);
+ assert(!lockfile);
+ error = lockfile_lock(cfg_name, timeout, &lockfile);
+ if (error) {
+ return error;
}
- lock_fd = fd;
cfg_read();
if (cookie) {
+ uint8_t curr_cookie[CFG_COOKIE_LEN];
cfg_get_cookie(curr_cookie);
if (memcmp(curr_cookie, cookie, sizeof *curr_cookie)) {