/*
- * Copyright (c) 2008, 2009 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
+#include "command-line.h"
#include "fatal-signal.h"
#include "dirs.h"
#include "lockfile.h"
+#include "process.h"
#include "socket-util.h"
#include "timeval.h"
#include "util.h"
/* Should we chdir to "/"? */
static bool chdir_ = true;
-/* File descriptors used by daemonize_start() and daemonize_complete(). */
-static int daemonize_fds[2];
+/* File descriptor used by daemonize_start() and daemonize_complete(). */
+static int daemonize_fd = -1;
+
+/* --monitor: Should a supervisory process monitor the daemon and restart it if
+ * it dies due to an error signal? */
+static bool monitor;
/* Returns the file name that would be used for a pidfile if 'name' were
* provided to set_pidfile(). The caller must free the returned string. */
return detach;
}
+/* Sets up a following call to daemonize() to fork a supervisory process to
+ * monitor the daemon and restart it if it dies due to an error signal. */
+void
+daemon_set_monitor(void)
+{
+ monitor = true;
+}
+
/* If a pidfile has been configured and that pidfile already exists and is
* locked by a running process, returns the pid of the running process.
* Otherwise, returns 0. */
daemonize_complete();
}
+static pid_t
+fork_and_wait_for_startup(int *fdp)
+{
+ int fds[2];
+ pid_t pid;
+
+ if (pipe(fds) < 0) {
+ ovs_fatal(errno, "pipe failed");
+ }
+
+ pid = fork();
+ if (pid > 0) {
+ /* Running in parent process. */
+ char c;
+
+ close(fds[1]);
+ fatal_signal_fork();
+ if (read(fds[0], &c, 1) != 1) {
+ int retval;
+ int status;
+
+ do {
+ retval = waitpid(pid, &status, 0);
+ } while (retval == -1 && errno == EINTR);
+
+ if (retval == pid
+ && WIFEXITED(status)
+ && WEXITSTATUS(status)) {
+ /* Child exited with an error. Convey the same error to
+ * our parent process as a courtesy. */
+ exit(WEXITSTATUS(status));
+ }
+
+ ovs_fatal(errno, "fork child failed to signal startup");
+ }
+ close(fds[0]);
+ *fdp = -1;
+ } else if (!pid) {
+ /* Running in child process. */
+ close(fds[0]);
+ time_postfork();
+ lockfile_postfork();
+ *fdp = fds[1];
+ } else {
+ ovs_fatal(errno, "could not fork");
+ }
+
+ return pid;
+}
+
+static void
+fork_notify_startup(int fd)
+{
+ if (fd != -1) {
+ size_t bytes_written;
+ int error;
+
+ error = write_fully(fd, "", 1, &bytes_written);
+ if (error) {
+ ovs_fatal(error, "could not write to pipe");
+ }
+
+ close(fd);
+ }
+}
+
+static bool
+should_restart(int status)
+{
+ if (WIFSIGNALED(status)) {
+ static const int error_signals[] = {
+ SIGABRT, SIGALRM, SIGBUS, SIGFPE, SIGILL, SIGPIPE, SIGSEGV,
+ SIGXCPU, SIGXFSZ
+ };
+
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(error_signals); i++) {
+ if (error_signals[i] == WTERMSIG(status)) {
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+static void
+monitor_daemon(pid_t daemon_pid)
+{
+ /* XXX Should limit the rate at which we restart the daemon. */
+ /* XXX Should log daemon's stderr output at startup time. */
+ const char *saved_program_name;
+ char *status_msg;
+
+ saved_program_name = program_name;
+ program_name = xasprintf("monitor(%s)", program_name);
+ status_msg = xstrdup("healthy");
+ for (;;) {
+ int retval;
+ int status;
+
+ proctitle_set("%s: monitoring pid %lu (%s)",
+ saved_program_name, (unsigned long int) daemon_pid,
+ status_msg);
+
+ do {
+ retval = waitpid(daemon_pid, &status, 0);
+ } while (retval == -1 && errno == EINTR);
+
+ if (retval == -1) {
+ ovs_fatal(errno, "waitpid failed");
+ } else if (retval == daemon_pid) {
+ char *s = process_status_msg(status);
+ free(status_msg);
+ status_msg = xasprintf("pid %lu died, %s",
+ (unsigned long int) daemon_pid, s);
+ free(s);
+
+ if (should_restart(status)) {
+ VLOG_ERR("%s, restarting", status_msg);
+ daemon_pid = fork_and_wait_for_startup(&daemonize_fd);
+ if (!daemon_pid) {
+ break;
+ }
+ } else {
+ VLOG_INFO("%s, exiting", status_msg);
+ exit(0);
+ }
+ }
+ }
+
+ /* Running in new daemon process. */
+ proctitle_restore();
+ free((char *) program_name);
+ program_name = saved_program_name;
+}
+
+/* Close stdin, stdout, stderr. If we're started from e.g. an SSH session,
+ * then this keeps us from holding that session open artificially. */
+static void
+close_standard_fds(void)
+{
+ int null_fd = get_null_fd();
+ if (null_fd >= 0) {
+ dup2(null_fd, STDIN_FILENO);
+ dup2(null_fd, STDOUT_FILENO);
+ dup2(null_fd, STDERR_FILENO);
+ }
+}
+
/* If daemonization is configured, then starts daemonization, by forking and
* returning in the child process. The parent process hangs around until the
* child lets it know either that it completed startup successfully (by calling
void
daemonize_start(void)
{
- if (detach) {
- pid_t pid;
+ daemonize_fd = -1;
- if (pipe(daemonize_fds) < 0) {
- ovs_fatal(errno, "pipe failed");
+ if (detach) {
+ if (fork_and_wait_for_startup(&daemonize_fd) > 0) {
+ /* Running in parent process. */
+ exit(0);
}
+ /* Running in daemon or monitor process. */
+ }
- pid = fork();
- if (pid > 0) {
- /* Running in parent process. */
- char c;
-
- close(daemonize_fds[1]);
- fatal_signal_fork();
- if (read(daemonize_fds[0], &c, 1) != 1) {
- int retval;
- int status;
-
- do {
- retval = waitpid(pid, &status, 0);
- } while (retval == -1 && errno == EINTR);
-
- if (retval == pid
- && WIFEXITED(status)
- && WEXITSTATUS(status)) {
- /* Child exited with an error. Convey the same error to
- * our parent process as a courtesy. */
- exit(WEXITSTATUS(status));
- }
+ if (monitor) {
+ int saved_daemonize_fd = daemonize_fd;
+ pid_t daemon_pid;
- ovs_fatal(errno, "daemon child failed to signal startup");
- }
- exit(0);
- } else if (!pid) {
- /* Running in child process. */
- close(daemonize_fds[0]);
- make_pidfile();
- time_postfork();
- lockfile_postfork();
- } else {
- ovs_fatal(errno, "could not fork");
+ daemon_pid = fork_and_wait_for_startup(&daemonize_fd);
+ if (daemon_pid > 0) {
+ /* Running in monitor process. */
+ fork_notify_startup(saved_daemonize_fd);
+ close_standard_fds();
+ monitor_daemon(daemon_pid);
}
- } else {
- make_pidfile();
+ /* Running in daemon process. */
}
+
+ make_pidfile();
}
/* If daemonization is configured, then this function notifies the parent
void
daemonize_complete(void)
{
- if (detach) {
- size_t bytes_written;
- int error;
+ fork_notify_startup(daemonize_fd);
- error = write_fully(daemonize_fds[1], "", 1, &bytes_written);
- if (error) {
- ovs_fatal(error, "could not write to pipe");
- }
-
- close(daemonize_fds[1]);
+ if (detach) {
setsid();
if (chdir_) {
ignore(chdir("/"));
}
+ close_standard_fds();
}
}
git://git.onelab.eu / sliver-openvswitch.git / blobdiff