mir/ovs
2
0
Fork 0
mirror of https://github.com/openvswitch/ovs synced 2025-08-31 22:35:15 +00:00
Code Issues Releases Wiki Activity

daemon: Add support for process monitoring and restart.

Browse Source
This commit is contained in:
Ben Pfaff
2010-01-15 12:13:46 -08:00
parent 7943cd51e7
commit ff8decf1a3
6 changed files with 277 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

90
lib/daemon.c
View File

@@ -25,6 +25,7 @@
#include "fatal-signal.h"
#include "dirs.h"
#include "lockfile.h"
#include "process.h"
#include "socket-util.h"
#include "timeval.h"
#include "util.h"
@@ -47,6 +48,10 @@ static bool chdir_ = true;
/* 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. */
char *
@@ -117,6 +122,14 @@ get_detach(void)
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. */
@@ -286,6 +299,69 @@ fork_notify_startup(int 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;
saved_program_name = program_name;
program_name = xasprintf("monitor(%s)", program_name);
for (;;) {
int retval;
int status;
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 *status_msg = process_status_msg(status);
if (should_restart(status)) {
VLOG_ERR("%s daemon died unexpectedly (%s), restarting",
saved_program_name, status_msg);
free(status_msg);
daemon_pid = fork_and_wait_for_startup(&daemonize_fd);
if (!daemon_pid) {
break;
}
} else {
VLOG_INFO("%s daemon exited normally (%s), exiting",
saved_program_name, status_msg);
exit(0);
}
}
}
/* Running in new daemon process. */
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
@@ -314,6 +390,20 @@ daemonize_start(void)
/* Running in parent process. */
exit(0);
}
/* Running in daemon or monitor process. */
}
if (monitor) {
int saved_daemonize_fd = daemonize_fd;
pid_t daemon_pid;
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);
}
/* Running in daemon process. */
}

11
lib/daemon.h
View File

@@ -1,5 +1,5 @@
/*
* 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.
@@ -26,13 +26,15 @@ enum {
OPT_NO_CHDIR,
OPT_OVERWRITE_PIDFILE,
OPT_PIDFILE,
OPT_MONITOR
};
#define DAEMON_LONG_OPTIONS \
{"detach", no_argument, 0, OPT_DETACH}, \
{"no-chdir", no_argument, 0, OPT_NO_CHDIR}, \
{"pidfile", optional_argument, 0, OPT_PIDFILE}, \
{"overwrite-pidfile", no_argument, 0, OPT_OVERWRITE_PIDFILE}
{"overwrite-pidfile", no_argument, 0, OPT_OVERWRITE_PIDFILE},\
{"monitor", no_argument, 0, OPT_MONITOR}
#define DAEMON_OPTION_HANDLERS \
case OPT_DETACH: \
@@ -49,6 +51,10 @@ enum {
\
case OPT_OVERWRITE_PIDFILE: \
ignore_existing_pidfile(); \
break; \
\
case OPT_MONITOR: \
daemon_set_monitor(); \
break;
char *make_pidfile_name(const char *name);
@@ -58,6 +64,7 @@ void set_no_chdir(void);
bool is_chdir_enabled(void);
void set_detach(void);
bool get_detach(void);
void daemon_set_monitor(void);
void daemonize(void);
void daemonize_start(void);
void daemonize_complete(void);

11
lib/daemon.man
View File

@@ -19,6 +19,17 @@ When \fB--pidfile\fR is not specified, this option has no effect.
Causes \fB\*(PN\fR to detach itself from the foreground session and
run as a background process.
.TP
\fB--monitor\fR
Creates an additional process to monitor the \fB\*(PN\fR daemon. If
the daemon dies due to a signal that indicates a programming error
(e.g. \fBSIGSEGV\fR, \fBSIGABRT\fR), then the monitor process starts a
new copy of it. If the daemon die or exits for another reason, the
monitor process exits.
.IP
This option is normally used with \fB--detach\fR, but it also
functions without it.
.TP
\fB--no-chdir\fR
By default, when \fB--detach\fR is specified, \fB\*(PN\fR

1
tests/automake.mk
View File

@@ -9,6 +9,7 @@ TESTSUITE_AT = \
tests/ovsdb-macros.at \
tests/lcov-pre.at \
tests/library.at \
tests/daemon.at \
tests/vconn.at \
tests/dir_name.at \
tests/aes128.at \

165
tests/daemon.at Normal file
View File

@@ -0,0 +1,165 @@
AT_BANNER([daemon unit tests])
AT_SETUP([daemon])
OVSDB_INIT([db])
AT_CAPTURE_FILE([pid])
AT_CAPTURE_FILE([expected])
# Start the daemon and wait for the pidfile to get created
# and that its contents are the correct pid.
AT_CHECK([ovsdb-server --pidfile=$PWD/pid --remote=punix:socket --unixctl=$PWD/unixctl db& echo $! > expected], [0], [ignore], [ignore])
OVS_WAIT_UNTIL([test -s pid], [kill `cat expected`])
AT_CHECK(
[pid=`cat pid` && expected=`cat expected` && test "$pid" = "$expected"],
[0], [], [], [kill `cat expected`])
AT_CHECK([kill -0 `cat pid`], [0], [], [], [kill `cat expected`])
# Kill the daemon and make sure that the pidfile gets deleted.
kill `cat expected`
OVS_WAIT_WHILE([kill -0 `cat expected`])
AT_CHECK([test ! -e pid])
AT_CLEANUP
AT_SETUP([daemon --monitor])
OVSDB_INIT([db])
AT_CAPTURE_FILE([pid])
AT_CAPTURE_FILE([parent])
AT_CAPTURE_FILE([parentpid])
AT_CAPTURE_FILE([newpid])
# Start the daemon and wait for the pidfile to get created.
AT_CHECK([ovsdb-server --monitor --pidfile=$PWD/pid --remote=punix:socket --unixctl=$PWD/unixctl db& echo $! > parent], [0], [ignore], [ignore])
OVS_WAIT_UNTIL([test -s pid], [kill `cat parent`])
# Check that the pidfile names a running process,
# and that the parent process of that process is our child process.
AT_CHECK([kill -0 `cat pid`], [0], [], [], [kill `cat parent`])
AT_CHECK([ps -o ppid= -p `cat pid` > parentpid],
[0], [], [], [kill `cat parent`])
AT_CHECK(
[parentpid=`cat parentpid` &&
parent=`cat parent` &&
test $parentpid = $parent],
[0], [], [], [kill `cat parent`])
# Kill the daemon process, making it look like a segfault,
# and wait for a new child process to get spawned.
AT_CHECK([cp pid oldpid], [0], [], [], [kill `cat parent`])
AT_CHECK([kill -SEGV `cat pid`], [0], [], [ignore], [kill `cat parent`])
OVS_WAIT_WHILE([kill -0 `cat oldpid`], [kill `cat parent`])
OVS_WAIT_UNTIL([test -s pid && test `cat pid` != `cat oldpid`],
[kill `cat parent`])
AT_CHECK([cp pid newpid], [0], [], [], [kill `cat parent`])
# Check that the pidfile names a running process,
# and that the parent process of that process is our child process.
AT_CHECK([ps -o ppid= -p `cat pid` > parentpid],
[0], [], [], [kill `cat parent`])
AT_CHECK(
[parentpid=`cat parentpid` &&
parent=`cat parent` &&
test $parentpid = $parent],
[0], [], [], [kill `cat parent`])
# Kill the daemon process with SIGTERM, and wait for the daemon
# and the monitor processes to go away and the pidfile to get deleted.
AT_CHECK([kill `cat pid`], [0], [], [ignore], [kill `cat parent`])
OVS_WAIT_WHILE([kill -0 `cat parent` || kill -0 `cat newpid` || test -e pid],
[kill `cat parent`])
AT_CLEANUP
AT_SETUP([daemon --detach])
AT_CAPTURE_FILE([pid])
OVSDB_INIT([db])
# Start the daemon and make sure that the pidfile exists immediately.
# We don't wait for the pidfile to get created because the daemon is
# supposed to do so before the parent exits.
AT_CHECK([ovsdb-server --detach --pidfile=$PWD/pid --remote=punix:socket --unixctl=$PWD/unixctl db], [0], [ignore], [ignore])
AT_CHECK([test -s pid])
AT_CHECK([kill -0 `cat pid`])
# Kill the daemon and make sure that the pidfile gets deleted.
cp pid saved-pid
kill `cat pid`
OVS_WAIT_WHILE([kill -0 `cat saved-pid`])
AT_CHECK([test ! -e pid])
AT_CLEANUP
AT_SETUP([daemon --detach --monitor])
m4_define([CHECK],
[AT_CHECK([$1], [$2], [$3], [$4], [kill `cat daemon monitor`])])
OVSDB_INIT([db])
AT_CAPTURE_FILE([daemon])
AT_CAPTURE_FILE([olddaemon])
AT_CAPTURE_FILE([newdaemon])
AT_CAPTURE_FILE([monitor])
AT_CAPTURE_FILE([newmonitor])
AT_CAPTURE_FILE([init])
# Start the daemon and make sure that the pidfile exists immediately.
# We don't wait for the pidfile to get created because the daemon is
# supposed to do so before the parent exits.
AT_CHECK([ovsdb-server --detach --pidfile=$PWD/daemon --monitor --remote=punix:socket --unixctl=$PWD/unixctl db], [0], [ignore], [ignore])
AT_CHECK([test -s daemon])
# Check that the pidfile names a running process,
# and that the parent process of that process is a running process,
# and that the parent process of that process is init.
CHECK([kill -0 `cat daemon`])
CHECK([ps -o ppid= -p `cat daemon` > monitor])
CHECK([kill -0 `cat monitor`])
CHECK([ps -o ppid= -p `cat monitor` > init])
CHECK([test `cat init` = 1])
# Kill the daemon process, making it look like a segfault,
# and wait for a new daemon process to get spawned.
CHECK([cp daemon olddaemon])
CHECK([kill -SEGV `cat daemon`], [0], [ignore], [ignore])
OVS_WAIT_WHILE([kill -0 `cat olddaemon`], [kill `cat olddaemon daemon`])
OVS_WAIT_UNTIL([test -s daemon && test `cat daemon` != `cat olddaemon`],
[kill `cat olddaemon daemon`])
CHECK([cp daemon newdaemon])
# Check that the pidfile names a running process,
# and that the parent process of that process is our child process.
CHECK([kill -0 `cat daemon`])
CHECK([diff olddaemon newdaemon], [1], [ignore])
CHECK([ps -o ppid= -p `cat daemon` > newmonitor])
CHECK([diff monitor newmonitor])
CHECK([kill -0 `cat newmonitor`])
CHECK([ps -o ppid= -p `cat newmonitor` > init])
CHECK([test `cat init` = 1])
# Kill the daemon process with SIGTERM, and wait for the daemon
# and the monitor processes to go away and the pidfile to get deleted.
CHECK([kill `cat daemon`], [0], [], [ignore])
OVS_WAIT_WHILE(
[kill -0 `cat monitor` || kill -0 `cat newdaemon` || test -e daemon],
[kill `cat monitor newdaemon`])
m4_undefine([CHECK])
AT_CLEANUP
AT_SETUP([daemon --detach startup errors])
AT_CAPTURE_FILE([pid])
OVSDB_INIT([db])
OVS_CHECK_LCOV([ovsdb-server --detach --pidfile=$PWD/pid --unixctl=$PWD/nonexistent/unixctl db], [1], [], [stderr])
AT_CHECK([grep 'ovsdb-server: could not initialize control socket' stderr],
[0], [ignore], [])
AT_CHECK([test ! -s pid])
AT_CLEANUP
AT_SETUP([daemon --detach --monitor startup errors])
AT_CAPTURE_FILE([pid])
OVSDB_INIT([db])
OVS_CHECK_LCOV([ovsdb-server --detach --pidfile=$PWD/pid --monitor --unixctl=$PWD/nonexistent/unixctl db], [1], [], [stderr])
AT_CHECK([grep 'ovsdb-server: could not initialize control socket' stderr],
[0], [ignore], [])
AT_CHECK([test ! -s pid])
AT_CLEANUP
AT_SETUP([daemon --detach closes standard fds])
AT_CAPTURE_FILE([pid])
OVSDB_INIT([db])
AT_CHECK([(yes; echo $? > status) | ovsdb-server --detach --pidfile=$PWD/pid --unixctl=$PWD/unixctl db], [0], [], [stderr])
AT_CHECK([kill `cat pid`])
AT_CHECK([test -s status])
AT_CHECK([kill -l `cat status`], [0], [PIPE
])
AT_CLEANUP
AT_SETUP([daemon --detach --monitor closes standard fds])
AT_CAPTURE_FILE([pid])
OVSDB_INIT([db])
AT_CHECK([(yes; echo $? > status) | ovsdb-server --detach --monitor --pidfile=$PWD/pid --unixctl=$PWD/unixctl db], [0], [], [stderr])
AT_CHECK([kill `cat pid`])
AT_CHECK([test -s status])
AT_CHECK([kill -l `cat status`], [0], [PIPE
])
AT_CLEANUP

1
tests/testsuite.at
View File

@@ -39,6 +39,7 @@ m4_include([tests/ovsdb-macros.at])
m4_include([tests/lcov-pre.at])
m4_include([tests/library.at])
m4_include([tests/daemon.at])
m4_include([tests/vconn.at])
m4_include([tests/dir_name.at])
m4_include([tests/aes128.at])