External/libvirt
1
0
Fork 0
mirror of https://gitlab.com/libvirt/libvirt.git synced 2025-03-07 17:28:15 +00:00
Code

virtlockd: make re-exec more robust

Browse Source 
- Use $XDG_RUNTIME_DIR for re-exec state file when running unprivileged.

- argv[0] may not contain a full path to the binary, however it should
  contain something that can be looked up in the PATH. Use execvp() to
  do path lookup on re-exec.

- As per list discussion [1], ignore --daemon on re-exec.

[1] https://www.redhat.com/archives/libvir-list/2013-December/msg00514.html

Signed-off-by: Michael Chapman <mike@very.puzzling.org>
This commit is contained in:
Michael Chapman 2013-12-11 19:07:45 +11:00 committed by Michal Privoznik
parent 2a27d6a4f2
commit 881a2cff0d
1 changed files with 95 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

129
src/locking/lock_daemon.c
View File

@ -923,7 +923,42 @@ error:
}
#define VIR_LOCK_DAEMON_RESTART_EXEC_FILE LOCALSTATEDIR "/run/virtlockd-restart-exec.json"
static int
virLockDaemonExecRestartStatePath(bool privileged,
char **state_file)
{
if (privileged) {
if (VIR_STRDUP(*state_file, LOCALSTATEDIR "/run/virtlockd-restart-exec.json") < 0)
goto error;
} else {
char *rundir = NULL;
mode_t old_umask;
if (!(rundir = virGetUserRuntimeDirectory()))
goto error;
old_umask = umask(077);
if (virFileMakePath(rundir) < 0) {
umask(old_umask);
VIR_FREE(rundir);
goto error;
}
umask(old_umask);
if (virAsprintf(state_file, "%s/virtlockd-restart-exec.json", rundir) < 0) {
VIR_FREE(rundir);
goto error;
}
VIR_FREE(rundir);
}
return 0;
error:
return -1;
}
static char *
virLockDaemonGetExecRestartMagic(void)
@ -936,7 +971,10 @@ virLockDaemonGetExecRestartMagic(void)
static int
virLockDaemonPostExecRestart(bool privileged)
virLockDaemonPostExecRestart(const char *state_file,
const char *pid_file,
int *pid_file_fd,
bool privileged)
{
const char *gotmagic;
char *wantmagic = NULL;
@ -946,14 +984,14 @@ virLockDaemonPostExecRestart(bool privileged)
VIR_DEBUG("Running post-restart exec");
if (!virFileExists(VIR_LOCK_DAEMON_RESTART_EXEC_FILE)) {
VIR_DEBUG("No restart file %s present",
VIR_LOCK_DAEMON_RESTART_EXEC_FILE);
if (!virFileExists(state_file)) {
VIR_DEBUG("No restart state file %s present",
state_file);
ret = 0;
goto cleanup;
}
if (virFileReadAll(VIR_LOCK_DAEMON_RESTART_EXEC_FILE,
if (virFileReadAll(state_file,
1024 * 1024 * 10, /* 10 MB */
&state) < 0)
goto cleanup;
@ -980,13 +1018,18 @@ virLockDaemonPostExecRestart(bool privileged)
goto cleanup;
}
/* Re-claim PID file now as we will not be daemonizing */
if (pid_file &&
(*pid_file_fd = virPidFileAcquirePath(pid_file, getpid())) < 0)
goto cleanup;
if (!(lockDaemon = virLockDaemonNewPostExecRestart(object, privileged)))
goto cleanup;
ret = 1;
cleanup:
unlink(VIR_LOCK_DAEMON_RESTART_EXEC_FILE);
unlink(state_file);
VIR_FREE(wantmagic);
VIR_FREE(state);
virJSONValueFree(object);
@ -995,7 +1038,8 @@ cleanup:
static int
virLockDaemonPreExecRestart(virNetServerPtr srv,
virLockDaemonPreExecRestart(const char *state_file,
virNetServerPtr srv,
char **argv)
{
virJSONValuePtr child;
@ -1063,15 +1107,15 @@ virLockDaemonPreExecRestart(virNetServerPtr srv,
VIR_DEBUG("Saving state %s", state);
if (virFileWriteStr(VIR_LOCK_DAEMON_RESTART_EXEC_FILE,
if (virFileWriteStr(state_file,
state, 0700) < 0) {
virReportSystemError(errno,
_("Unable to save state file %s"),
VIR_LOCK_DAEMON_RESTART_EXEC_FILE);
state_file);
goto cleanup;
}
if (execv(argv[0], argv) < 0) {
if (execvp(argv[0], argv) < 0) {
virReportSystemError(errno, "%s",
_("Unable to restart self"));
goto cleanup;
@ -1151,6 +1195,7 @@ int main(int argc, char **argv) {
char *pid_file = NULL;
int pid_file_fd = -1;
char *sock_file = NULL;
char *state_file = NULL;
bool implicit_conf = false;
mode_t old_umask;
bool privileged = false;
@ -1274,21 +1319,13 @@ int main(int argc, char **argv) {
VIR_DEBUG("Decided on socket paths '%s'",
sock_file);
if (godaemon) {
char ebuf[1024];
if (chdir("/") < 0) {
VIR_ERROR(_("cannot change to root directory: %s"),
virStrerror(errno, ebuf, sizeof(ebuf)));
goto cleanup;
}
if ((statuswrite = virLockDaemonForkIntoBackground(argv[0])) < 0) {
VIR_ERROR(_("Failed to fork as daemon: %s"),
virStrerror(errno, ebuf, sizeof(ebuf)));
goto cleanup;
}
if (virLockDaemonExecRestartStatePath(privileged,
&state_file) < 0) {
VIR_ERROR(_("Can't determine restart state file path"));
exit(EXIT_FAILURE);
}
VIR_DEBUG("Decided on restart state file path '%s'",
state_file);
/* Ensure the rundir exists (on tmpfs on some systems) */
if (privileged) {
@ -1315,20 +1352,41 @@ int main(int argc, char **argv) {
}
umask(old_umask);
/* If we have a pidfile set, claim it now, exiting if already taken */
if ((pid_file_fd = virPidFileAcquirePath(pid_file, getpid())) < 0) {
ret = VIR_LOCK_DAEMON_ERR_PIDFILE;
goto cleanup;
}
if ((rv = virLockDaemonPostExecRestart(privileged)) < 0) {
if ((rv = virLockDaemonPostExecRestart(state_file,
pid_file,
&pid_file_fd,
privileged)) < 0) {
ret = VIR_LOCK_DAEMON_ERR_INIT;
goto cleanup;
}
/* rv == 1, means we setup everything from saved state,
* so we only setup stuff from scratch if rv == 0 */
* so only (possibly) daemonize and setup stuff from
* scratch if rv == 0
*/
if (rv == 0) {
if (godaemon) {
char ebuf[1024];
if (chdir("/") < 0) {
VIR_ERROR(_("cannot change to root directory: %s"),
virStrerror(errno, ebuf, sizeof(ebuf)));
goto cleanup;
}
if ((statuswrite = virLockDaemonForkIntoBackground(argv[0])) < 0) {
VIR_ERROR(_("Failed to fork as daemon: %s"),
virStrerror(errno, ebuf, sizeof(ebuf)));
goto cleanup;
}
}
/* If we have a pidfile set, claim it now, exiting if already taken */
if ((pid_file_fd = virPidFileAcquirePath(pid_file, getpid())) < 0) {
ret = VIR_LOCK_DAEMON_ERR_PIDFILE;
goto cleanup;
}
if (!(lockDaemon = virLockDaemonNew(config, privileged))) {
ret = VIR_LOCK_DAEMON_ERR_INIT;
goto cleanup;
@ -1386,7 +1444,9 @@ int main(int argc, char **argv) {
virNetServerRun(lockDaemon->srv);
if (execRestart &&
virLockDaemonPreExecRestart(lockDaemon->srv, argv) < 0)
virLockDaemonPreExecRestart(state_file,
lockDaemon->srv,
argv) < 0)
ret = VIR_LOCK_DAEMON_ERR_REEXEC;
else
ret = 0;
@ -1408,6 +1468,7 @@ cleanup:
virPidFileReleasePath(pid_file, pid_file_fd);
VIR_FREE(pid_file);
VIR_FREE(sock_file);
VIR_FREE(state_file);
VIR_FREE(run_dir);
return ret;