runit/sv.c - codeaurora/busybox - Gitiles

 /*
 Copyright (c) 2001-2006, Gerrit Pape
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
    3. The name of the author may not be used to endorse or promote products
       derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

 /* Taken from http://smarden.sunsite.dk/runit/sv.8.html:

 sv - control and manage services monitored by runsv

 sv [-v] [-w sec] command services
 /etc/init.d/service [-w sec] command

 The sv program reports the current status and controls the state of services
 monitored by the runsv(8) supervisor.

 services consists of one or more arguments, each argument naming a directory
 service used by runsv(8). If service doesn't start with a dot or slash,
 it is searched in the default services directory /var/service/, otherwise
 relative to the current directory.

 command is one of up, down, status, once, pause, cont, hup, alarm, interrupt,
 1, 2, term, kill, or exit, or start, stop, restart, shutdown, force-stop,
 force-reload, force-restart, force-shutdown.

 The sv program can be sym-linked to /etc/init.d/ to provide an LSB init
 script interface. The service to be controlled then is specified by the
 base name of the "init script".

 status
     Report the current status of the service, and the appendant log service
     if available, to standard output.
 up
     If the service is not running, start it. If the service stops, restart it.
 down
     If the service is running, send it the TERM signal, and the CONT signal.
     If ./run exits, start ./finish if it exists. After it stops, do not
     restart service.
 once
     If the service is not running, start it. Do not restart it if it stops.
 pause cont hup alarm interrupt quit 1 2 term kill
     If the service is running, send it the STOP, CONT, HUP, ALRM, INT, QUIT,
     USR1, USR2, TERM, or KILL signal respectively.
 exit
     If the service is running, send it the TERM signal, and the CONT signal.
     Do not restart the service. If the service is down, and no log service
     exists, runsv(8) exits. If the service is down and a log service exists,
     send the TERM signal to the log service. If the log service is down,
     runsv(8) exits. This command is ignored if it is given to an appendant
     log service.

 sv actually looks only at the first character of above commands.

 Commands compatible to LSB init script actions:

 status
     Same as status.
 start
     Same as up, but wait up to 7 seconds for the command to take effect.
     Then report the status or timeout. If the script ./check exists in
     the service directory, sv runs this script to check whether the service
     is up and available; it's considered to be available if ./check exits
     with 0.
 stop
     Same as down, but wait up to 7 seconds for the service to become down.
     Then report the status or timeout.
 restart
     Send the commands term, cont, and up to the service, and wait up to
     7 seconds for the service to restart. Then report the status or timeout.
     If the script ./check exists in the service directory, sv runs this script
     to check whether the service is up and available again; it's considered
     to be available if ./check exits with 0.
 shutdown
     Same as exit, but wait up to 7 seconds for the runsv(8) process
     to terminate. Then report the status or timeout.
 force-stop
     Same as down, but wait up to 7 seconds for the service to become down.
     Then report the status, and on timeout send the service the kill command.
 force-reload
     Send the service the term and cont commands, and wait up to
     7 seconds for the service to restart. Then report the status,
     and on timeout send the service the kill command.
 force-restart
     Send the service the term, cont and up commands, and wait up to
     7 seconds for the service to restart. Then report the status, and
     on timeout send the service the kill command. If the script ./check
     exists in the service directory, sv runs this script to check whether
     the service is up and available again; it's considered to be available
     if ./check exits with 0.
 force-shutdown
     Same as exit, but wait up to 7 seconds for the runsv(8) process to
     terminate. Then report the status, and on timeout send the service
     the kill command.

 Additional Commands

 check
     Check for the service to be in the state that's been requested. Wait up to
     7 seconds for the service to reach the requested state, then report
     the status or timeout. If the requested state of the service is up,
     and the script ./check exists in the service directory, sv runs
     this script to check whether the service is up and running;
     it's considered to be up if ./check exits with 0.

 Options

 -v
     wait up to 7 seconds for the command to take effect.
     Then report the status or timeout.
 -w sec
     Override the default timeout of 7 seconds with sec seconds. Implies -v.

 Environment

 SVDIR
     The environment variable $SVDIR overrides the default services directory
     /var/service.
 SVWAIT
     The environment variable $SVWAIT overrides the default 7 seconds to wait
     for a command to take effect. It is overridden by the -w option.

 Exit Codes
     sv exits 0, if the command was successfully sent to all services, and,
     if it was told to wait, the command has taken effect to all services.

     For each service that caused an error (e.g. the directory is not
     controlled by a runsv(8) process, or sv timed out while waiting),
     sv increases the exit code by one and exits non zero. The maximum
     is 99. sv exits 100 on error.
 */

 /* Busyboxed by Denys Vlasenko <vda.linux@googlemail.com> */

 //config:config SV
 //config:	bool "sv"
 //config:	default y
 //config:	help
 //config:	  sv reports the current status and controls the state of services
 //config:	  monitored by the runsv supervisor.
 //config:
 //config:config SV_DEFAULT_SERVICE_DIR
 //config:	string "Default directory for services"
 //config:	default "/var/service"
 //config:	depends on SV
 //config:	help
 //config:	  Default directory for services.
 //config:	  Defaults to "/var/service"

 //applet:IF_SV(APPLET(sv, BB_DIR_USR_BIN, BB_SUID_DROP))

 //kbuild:lib-$(CONFIG_SV) += sv.o

 //usage:#define sv_trivial_usage
 //usage:       "[-v] [-w SEC] CMD SERVICE_DIR..."
 //usage:#define sv_full_usage "\n\n"
 //usage:       "Control services monitored by runsv supervisor.\n"
 //usage:       "Commands (only first character is enough):\n"
 //usage:       "\n"
 //usage:       "status: query service status\n"
 //usage:       "up: if service isn't running, start it. If service stops, restart it\n"
 //usage:       "once: like 'up', but if service stops, don't restart it\n"
 //usage:       "down: send TERM and CONT signals. If ./run exits, start ./finish\n"
 //usage:       "	if it exists. After it stops, don't restart service\n"
 //usage:       "exit: send TERM and CONT signals to service and log service. If they exit,\n"
 //usage:       "	runsv exits too\n"
 //usage:       "pause, cont, hup, alarm, interrupt, quit, 1, 2, term, kill: send\n"
 //usage:       "STOP, CONT, HUP, ALRM, INT, QUIT, USR1, USR2, TERM, KILL signal to service"

 #include <sys/file.h>
 #include "libbb.h"
 #include "runit_lib.h"

 struct globals {
 	const char *acts;
 	char **service;
 	unsigned rc;
 /* "Bernstein" time format: unix + 0x400000000000000aULL */
 	uint64_t tstart, tnow;
 	svstatus_t svstatus;
 } FIX_ALIASING;
 #define G (*(struct globals*)&bb_common_bufsiz1)
 #define acts         (G.acts        )
 #define service      (G.service     )
 #define rc           (G.rc          )
 #define tstart       (G.tstart      )
 #define tnow         (G.tnow        )
 #define svstatus     (G.svstatus    )
 #define INIT_G() do { } while (0)


 #define str_equal(s,t) (!strcmp((s), (t)))


 static void fatal_cannot(const char *m1) NORETURN;
 static void fatal_cannot(const char *m1)
 {
 	bb_perror_msg("fatal: can't %s", m1);
 	_exit(151);
 }

 static void out(const char *p, const char *m1)
 {
 	printf("%s%s: %s", p, *service, m1);
 	if (errno) {
 		printf(": %s", strerror(errno));
 	}
 	bb_putchar('\n'); /* will also flush the output */
 }

 #define WARN    "warning: "
 #define OK      "ok: "

 static void fail(const char *m1)
 {
 	++rc;
 	out("fail: ", m1);
 }
 static void failx(const char *m1)
 {
 	errno = 0;
 	fail(m1);
 }
 static void warn(const char *m1)
 {
 	++rc;
 	/* "warning: <service>: <m1>\n" */
 	out("warning: ", m1);
 }
 static void ok(const char *m1)
 {
 	errno = 0;
 	out(OK, m1);
 }

 static int svstatus_get(void)
 {
 	int fd, r;

 	fd = open("supervise/ok", O_WRONLY|O_NDELAY);
 	if (fd == -1) {
 		if (errno == ENODEV) {
 			*acts == 'x' ? ok("runsv not running")
 			             : failx("runsv not running");
 			return 0;
 		}
 		warn("can't open supervise/ok");
 		return -1;
 	}
 	close(fd);
 	fd = open("supervise/status", O_RDONLY|O_NDELAY);
 	if (fd == -1) {
 		warn("can't open supervise/status");
 		return -1;
 	}
 	r = read(fd, &svstatus, 20);
 	close(fd);
 	switch (r) {
 	case 20:
 		break;
 	case -1:
 		warn("can't read supervise/status");
 		return -1;
 	default:
 		errno = 0;
 		warn("can't read supervise/status: bad format");
 		return -1;
 	}
 	return 1;
 }

 static unsigned svstatus_print(const char *m)
 {
 	int diff;
 	int pid;
 	int normallyup = 0;
 	struct stat s;
 	uint64_t timestamp;

 	if (stat("down", &s) == -1) {
 		if (errno != ENOENT) {
 			bb_perror_msg(WARN"can't stat %s/down", *service);
 			return 0;
 		}
 		normallyup = 1;
 	}
 	pid = SWAP_LE32(svstatus.pid_le32);
 	timestamp = SWAP_BE64(svstatus.time_be64);
 	if (pid) {
 		switch (svstatus.run_or_finish) {
 		case 1: printf("run: "); break;
 		case 2: printf("finish: "); break;
 		}
 		printf("%s: (pid %d) ", m, pid);
 	} else {
 		printf("down: %s: ", m);
 	}
 	diff = tnow - timestamp;
 	printf("%us", (diff < 0 ? 0 : diff));
 	if (pid) {
 		if (!normallyup) printf(", normally down");
 		if (svstatus.paused) printf(", paused");
 		if (svstatus.want == 'd') printf(", want down");
 		if (svstatus.got_term) printf(", got TERM");
 	} else {
 		if (normallyup) printf(", normally up");
 		if (svstatus.want == 'u') printf(", want up");
 	}
 	return pid ? 1 : 2;
 }

 static int status(const char *unused UNUSED_PARAM)
 {
 	int r;

 	if (svstatus_get() <= 0)
 		return 0;

 	r = svstatus_print(*service);
 	if (chdir("log") == -1) {
 		if (errno != ENOENT) {
 			printf("; log: "WARN"can't change to log service directory: %s",
 					strerror(errno));
 		}
 	} else if (svstatus_get()) {
 		printf("; ");
 		svstatus_print("log");
 	}
 	bb_putchar('\n'); /* will also flush the output */
 	return r;
 }

 static int checkscript(void)
 {
 	char *prog[2];
 	struct stat s;
 	int pid, w;

 	if (stat("check", &s) == -1) {
 		if (errno == ENOENT) return 1;
 		bb_perror_msg(WARN"can't stat %s/check", *service);
 		return 0;
 	}
 	/* if (!(s.st_mode & S_IXUSR)) return 1; */
 	prog[0] = (char*)"./check";
 	prog[1] = NULL;
 	pid = spawn(prog);
 	if (pid <= 0) {
 		bb_perror_msg(WARN"can't %s child %s/check", "run", *service);
 		return 0;
 	}
 	while (safe_waitpid(pid, &w, 0) == -1) {
 		bb_perror_msg(WARN"can't %s child %s/check", "wait for", *service);
 		return 0;
 	}
 	return WEXITSTATUS(w) == 0;
 }

 static int check(const char *a)
 {
 	int r;
 	unsigned pid_le32;
 	uint64_t timestamp;

 	r = svstatus_get();
 	if (r == -1)
 		return -1;
 	if (r == 0) {
 		if (*a == 'x')
 			return 1;
 		return -1;
 	}
 	pid_le32 = svstatus.pid_le32;
 	switch (*a) {
 	case 'x':
 		return 0;
 	case 'u':
 		if (!pid_le32 || svstatus.run_or_finish != 1) return 0;
 		if (!checkscript()) return 0;
 		break;
 	case 'd':
 		if (pid_le32) return 0;
 		break;
 	case 'c':
 		if (pid_le32 && !checkscript()) return 0;
 		break;
 	case 't':
 		if (!pid_le32 && svstatus.want == 'd') break;
 		timestamp = SWAP_BE64(svstatus.time_be64);
 		if ((tstart > timestamp) || !pid_le32 || svstatus.got_term || !checkscript())
 			return 0;
 		break;
 	case 'o':
 		timestamp = SWAP_BE64(svstatus.time_be64);
 		if ((!pid_le32 && tstart > timestamp) || (pid_le32 && svstatus.want != 'd'))
 			return 0;
 	}
 	printf(OK);
 	svstatus_print(*service);
 	bb_putchar('\n'); /* will also flush the output */
 	return 1;
 }

 static int control(const char *a)
 {
 	int fd, r, l;

 /* Is it an optimization?
    It causes problems with "sv o SRV; ...; sv d SRV"
    ('d' is not passed to SRV because its .want == 'd'):
 	if (svstatus_get() <= 0)
 		return -1;
 	if (svstatus.want == *a)
 		return 0;
 */
 	fd = open("supervise/control", O_WRONLY|O_NDELAY);
 	if (fd == -1) {
 		if (errno != ENODEV)
 			warn("can't open supervise/control");
 		else
 			*a == 'x' ? ok("runsv not running") : failx("runsv not running");
 		return -1;
 	}
 	l = strlen(a);
 	r = write(fd, a, l);
 	close(fd);
 	if (r != l) {
 		warn("can't write to supervise/control");
 		return -1;
 	}
 	return 1;
 }

 int sv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int sv_main(int argc UNUSED_PARAM, char **argv)
 {
 	char *x;
 	char *action;
 	const char *varservice = CONFIG_SV_DEFAULT_SERVICE_DIR;
 	unsigned waitsec = 7;
 	smallint kll = 0;
 	int verbose = 0;
 	int (*act)(const char*);
 	int (*cbk)(const char*);
 	int curdir;

 	INIT_G();

 	xfunc_error_retval = 100;

 	x = getenv("SVDIR");
 	if (x) varservice = x;
 	x = getenv("SVWAIT");
 	if (x) waitsec = xatou(x);

 	opt_complementary = "w+:vv"; /* -w N, -v is a counter */
 	getopt32(argv, "w:v", &waitsec, &verbose);
 	argv += optind;
 	action = *argv++;
 	if (!action || !*argv) bb_show_usage();

 	tnow = time(NULL) + 0x400000000000000aULL;
 	tstart = tnow;
 	curdir = open(".", O_RDONLY|O_NDELAY);
 	if (curdir == -1)
 		fatal_cannot("open current directory");

 	act = &control;
 	acts = "s";
 	cbk = &check;

 	switch (*action) {
 	case 'x':
 	case 'e':
 		acts = "x";
 		if (!verbose) cbk = NULL;
 		break;
 	case 'X':
 	case 'E':
 		acts = "x";
 		kll = 1;
 		break;
 	case 'D':
 		acts = "d";
 		kll = 1;
 		break;
 	case 'T':
 		acts = "tc";
 		kll = 1;
 		break;
 	case 'c':
 		if (str_equal(action, "check")) {
 			act = NULL;
 			acts = "c";
 			break;
 		}
 	case 'u': case 'd': case 'o': case 't': case 'p': case 'h':
 	case 'a': case 'i': case 'k': case 'q': case '1': case '2':
 		action[1] = '\0';
 		acts = action;
 		if (!verbose) cbk = NULL;
 		break;
 	case 's':
 		if (str_equal(action, "shutdown")) {
 			acts = "x";
 			break;
 		}
 		if (str_equal(action, "start")) {
 			acts = "u";
 			break;
 		}
 		if (str_equal(action, "stop")) {
 			acts = "d";
 			break;
 		}
 		/* "status" */
 		act = &status;
 		cbk = NULL;
 		break;
 	case 'r':
 		if (str_equal(action, "restart")) {
 			acts = "tcu";
 			break;
 		}
 		bb_show_usage();
 	case 'f':
 		if (str_equal(action, "force-reload")) {
 			acts = "tc";
 			kll = 1;
 			break;
 		}
 		if (str_equal(action, "force-restart")) {
 			acts = "tcu";
 			kll = 1;
 			break;
 		}
 		if (str_equal(action, "force-shutdown")) {
 			acts = "x";
 			kll = 1;
 			break;
 		}
 		if (str_equal(action, "force-stop")) {
 			acts = "d";
 			kll = 1;
 			break;
 		}
 	default:
 		bb_show_usage();
 	}

 	service = argv;
 	while ((x = *service) != NULL) {
 		if (x[0] != '/' && x[0] != '.') {
 			if (chdir(varservice) == -1)
 				goto chdir_failed_0;
 		}
 		if (chdir(x) == -1) {
  chdir_failed_0:
 			fail("can't change to service directory");
 			goto nullify_service_0;
 		}
 		if (act && (act(acts) == -1)) {
  nullify_service_0:
 			*service = (char*) -1L; /* "dead" */
 		}
 		if (fchdir(curdir) == -1)
 			fatal_cannot("change to original directory");
 		service++;
 	}

 	if (cbk) while (1) {
 		int want_exit;
 		int diff;

 		diff = tnow - tstart;
 		service = argv;
 		want_exit = 1;
 		while ((x = *service) != NULL) {
 			if (x == (char*) -1L) /* "dead" */
 				goto next;
 			if (x[0] != '/' && x[0] != '.') {
 				if (chdir(varservice) == -1)
 					goto chdir_failed;
 			}
 			if (chdir(x) == -1) {
  chdir_failed:
 				fail("can't change to service directory");
 				goto nullify_service;
 			}
 			if (cbk(acts) != 0)
 				goto nullify_service;
 			want_exit = 0;
 			if (diff >= waitsec) {
 				printf(kll ? "kill: " : "timeout: ");
 				if (svstatus_get() > 0) {
 					svstatus_print(x);
 					++rc;
 				}
 				bb_putchar('\n'); /* will also flush the output */
 				if (kll)
 					control("k");
  nullify_service:
 				*service = (char*) -1L; /* "dead" */
 			}
 			if (fchdir(curdir) == -1)
 				fatal_cannot("change to original directory");
  next:
 			service++;
 		}
 		if (want_exit) break;
 		usleep(420000);
 		tnow = time(NULL) + 0x400000000000000aULL;
 	}
 	return rc > 99 ? 99 : rc;
 }
	/*
	Copyright (c) 2001-2006, Gerrit Pape
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are met:

	1. Redistributions of source code must retain the above copyright notice,
	this list of conditions and the following disclaimer.
	2. Redistributions in binary form must reproduce the above copyright
	notice, this list of conditions and the following disclaimer in the
	documentation and/or other materials provided with the distribution.
	3. The name of the author may not be used to endorse or promote products
	derived from this software without specific prior written permission.

	THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
	EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
	OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
	OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	/* Taken from http://smarden.sunsite.dk/runit/sv.8.html:

	sv - control and manage services monitored by runsv

	sv [-v] [-w sec] command services
	/etc/init.d/service [-w sec] command

	The sv program reports the current status and controls the state of services
	monitored by the runsv(8) supervisor.

	services consists of one or more arguments, each argument naming a directory
	service used by runsv(8). If service doesn't start with a dot or slash,
	it is searched in the default services directory /var/service/, otherwise
	relative to the current directory.

	command is one of up, down, status, once, pause, cont, hup, alarm, interrupt,
	1, 2, term, kill, or exit, or start, stop, restart, shutdown, force-stop,
	force-reload, force-restart, force-shutdown.

	The sv program can be sym-linked to /etc/init.d/ to provide an LSB init
	script interface. The service to be controlled then is specified by the
	base name of the "init script".

	status
	Report the current status of the service, and the appendant log service
	if available, to standard output.
	up
	If the service is not running, start it. If the service stops, restart it.
	down
	If the service is running, send it the TERM signal, and the CONT signal.
	If ./run exits, start ./finish if it exists. After it stops, do not
	restart service.
	once
	If the service is not running, start it. Do not restart it if it stops.
	pause cont hup alarm interrupt quit 1 2 term kill
	If the service is running, send it the STOP, CONT, HUP, ALRM, INT, QUIT,
	USR1, USR2, TERM, or KILL signal respectively.
	exit
	If the service is running, send it the TERM signal, and the CONT signal.
	Do not restart the service. If the service is down, and no log service
	exists, runsv(8) exits. If the service is down and a log service exists,
	send the TERM signal to the log service. If the log service is down,
	runsv(8) exits. This command is ignored if it is given to an appendant
	log service.

	sv actually looks only at the first character of above commands.

	Commands compatible to LSB init script actions:

	status
	Same as status.
	start
	Same as up, but wait up to 7 seconds for the command to take effect.
	Then report the status or timeout. If the script ./check exists in
	the service directory, sv runs this script to check whether the service
	is up and available; it's considered to be available if ./check exits
	with 0.
	stop
	Same as down, but wait up to 7 seconds for the service to become down.
	Then report the status or timeout.
	restart
	Send the commands term, cont, and up to the service, and wait up to
	7 seconds for the service to restart. Then report the status or timeout.
	If the script ./check exists in the service directory, sv runs this script
	to check whether the service is up and available again; it's considered
	to be available if ./check exits with 0.
	shutdown
	Same as exit, but wait up to 7 seconds for the runsv(8) process
	to terminate. Then report the status or timeout.
	force-stop
	Same as down, but wait up to 7 seconds for the service to become down.
	Then report the status, and on timeout send the service the kill command.
	force-reload
	Send the service the term and cont commands, and wait up to
	7 seconds for the service to restart. Then report the status,
	and on timeout send the service the kill command.
	force-restart
	Send the service the term, cont and up commands, and wait up to
	7 seconds for the service to restart. Then report the status, and
	on timeout send the service the kill command. If the script ./check
	exists in the service directory, sv runs this script to check whether
	the service is up and available again; it's considered to be available
	if ./check exits with 0.
	force-shutdown
	Same as exit, but wait up to 7 seconds for the runsv(8) process to
	terminate. Then report the status, and on timeout send the service
	the kill command.

	Additional Commands

	check
	Check for the service to be in the state that's been requested. Wait up to
	7 seconds for the service to reach the requested state, then report
	the status or timeout. If the requested state of the service is up,
	and the script ./check exists in the service directory, sv runs
	this script to check whether the service is up and running;
	it's considered to be up if ./check exits with 0.

	Options

	-v
	wait up to 7 seconds for the command to take effect.
	Then report the status or timeout.
	-w sec
	Override the default timeout of 7 seconds with sec seconds. Implies -v.

	Environment

	SVDIR
	The environment variable $SVDIR overrides the default services directory
	/var/service.
	SVWAIT
	The environment variable $SVWAIT overrides the default 7 seconds to wait
	for a command to take effect. It is overridden by the -w option.

	Exit Codes
	sv exits 0, if the command was successfully sent to all services, and,
	if it was told to wait, the command has taken effect to all services.

	For each service that caused an error (e.g. the directory is not
	controlled by a runsv(8) process, or sv timed out while waiting),
	sv increases the exit code by one and exits non zero. The maximum
	is 99. sv exits 100 on error.
	*/

	/* Busyboxed by Denys Vlasenko <vda.linux@googlemail.com> */

	//config:config SV
	//config: bool "sv"
	//config: default y
	//config: help
	//config: sv reports the current status and controls the state of services
	//config: monitored by the runsv supervisor.
	//config:
	//config:config SV_DEFAULT_SERVICE_DIR
	//config: string "Default directory for services"
	//config: default "/var/service"
	//config: depends on SV
	//config: help
	//config: Default directory for services.
	//config: Defaults to "/var/service"

	//applet:IF_SV(APPLET(sv, BB_DIR_USR_BIN, BB_SUID_DROP))

	//kbuild:lib-$(CONFIG_SV) += sv.o

	//usage:#define sv_trivial_usage
	//usage: "[-v] [-w SEC] CMD SERVICE_DIR..."
	//usage:#define sv_full_usage "\n\n"
	//usage: "Control services monitored by runsv supervisor.\n"
	//usage: "Commands (only first character is enough):\n"
	//usage: "\n"
	//usage: "status: query service status\n"
	//usage: "up: if service isn't running, start it. If service stops, restart it\n"
	//usage: "once: like 'up', but if service stops, don't restart it\n"
	//usage: "down: send TERM and CONT signals. If ./run exits, start ./finish\n"
	//usage: " if it exists. After it stops, don't restart service\n"
	//usage: "exit: send TERM and CONT signals to service and log service. If they exit,\n"
	//usage: " runsv exits too\n"
	//usage: "pause, cont, hup, alarm, interrupt, quit, 1, 2, term, kill: send\n"
	//usage: "STOP, CONT, HUP, ALRM, INT, QUIT, USR1, USR2, TERM, KILL signal to service"

	#include <sys/file.h>
	#include "libbb.h"
	#include "runit_lib.h"

	struct globals {
	const char *acts;
	char **service;
	unsigned rc;
	/* "Bernstein" time format: unix + 0x400000000000000aULL */
	uint64_t tstart, tnow;
	svstatus_t svstatus;
	} FIX_ALIASING;
	#define G ((struct globals)&bb_common_bufsiz1)
	#define acts (G.acts )
	#define service (G.service )
	#define rc (G.rc )
	#define tstart (G.tstart )
	#define tnow (G.tnow )
	#define svstatus (G.svstatus )
	#define INIT_G() do { } while (0)


	#define str_equal(s,t) (!strcmp((s), (t)))


	static void fatal_cannot(const char *m1) NORETURN;
	static void fatal_cannot(const char *m1)
	{
	bb_perror_msg("fatal: can't %s", m1);
	_exit(151);
	}

	static void out(const char p, const char m1)
	{
	printf("%s%s: %s", p, *service, m1);
	if (errno) {
	printf(": %s", strerror(errno));
	}
	bb_putchar('\n'); /* will also flush the output */
	}

	#define WARN "warning: "
	#define OK "ok: "

	static void fail(const char *m1)
	{
	++rc;
	out("fail: ", m1);
	}
	static void failx(const char *m1)
	{
	errno = 0;
	fail(m1);
	}
	static void warn(const char *m1)
	{
	++rc;
	/* "warning: <service>: <m1>\n" */
	out("warning: ", m1);
	}
	static void ok(const char *m1)
	{
	errno = 0;
	out(OK, m1);
	}

	static int svstatus_get(void)
	{
	int fd, r;

	fd = open("supervise/ok", O_WRONLY\|O_NDELAY);
	if (fd == -1) {
	if (errno == ENODEV) {
	*acts == 'x' ? ok("runsv not running")
	: failx("runsv not running");
	return 0;
	}
	warn("can't open supervise/ok");
	return -1;
	}
	close(fd);
	fd = open("supervise/status", O_RDONLY\|O_NDELAY);
	if (fd == -1) {
	warn("can't open supervise/status");
	return -1;
	}
	r = read(fd, &svstatus, 20);
	close(fd);
	switch (r) {
	case 20:
	break;
	case -1:
	warn("can't read supervise/status");
	return -1;
	default:
	errno = 0;
	warn("can't read supervise/status: bad format");
	return -1;
	}
	return 1;
	}

	static unsigned svstatus_print(const char *m)
	{
	int diff;
	int pid;
	int normallyup = 0;
	struct stat s;
	uint64_t timestamp;

	if (stat("down", &s) == -1) {
	if (errno != ENOENT) {
	bb_perror_msg(WARN"can't stat %s/down", *service);
	return 0;
	}
	normallyup = 1;
	}
	pid = SWAP_LE32(svstatus.pid_le32);
	timestamp = SWAP_BE64(svstatus.time_be64);
	if (pid) {
	switch (svstatus.run_or_finish) {
	case 1: printf("run: "); break;
	case 2: printf("finish: "); break;
	}
	printf("%s: (pid %d) ", m, pid);
	} else {
	printf("down: %s: ", m);
	}
	diff = tnow - timestamp;
	printf("%us", (diff < 0 ? 0 : diff));
	if (pid) {
	if (!normallyup) printf(", normally down");
	if (svstatus.paused) printf(", paused");
	if (svstatus.want == 'd') printf(", want down");
	if (svstatus.got_term) printf(", got TERM");
	} else {
	if (normallyup) printf(", normally up");
	if (svstatus.want == 'u') printf(", want up");
	}
	return pid ? 1 : 2;
	}

	static int status(const char *unused UNUSED_PARAM)
	{
	int r;

	if (svstatus_get() <= 0)
	return 0;

	r = svstatus_print(*service);
	if (chdir("log") == -1) {
	if (errno != ENOENT) {
	printf("; log: "WARN"can't change to log service directory: %s",
	strerror(errno));
	}
	} else if (svstatus_get()) {
	printf("; ");
	svstatus_print("log");
	}
	bb_putchar('\n'); /* will also flush the output */
	return r;
	}

	static int checkscript(void)
	{
	char *prog[2];
	struct stat s;
	int pid, w;

	if (stat("check", &s) == -1) {
	if (errno == ENOENT) return 1;
	bb_perror_msg(WARN"can't stat %s/check", *service);
	return 0;
	}
	/* if (!(s.st_mode & S_IXUSR)) return 1; */
	prog[0] = (char*)"./check";
	prog[1] = NULL;
	pid = spawn(prog);
	if (pid <= 0) {
	bb_perror_msg(WARN"can't %s child %s/check", "run", *service);
	return 0;
	}
	while (safe_waitpid(pid, &w, 0) == -1) {
	bb_perror_msg(WARN"can't %s child %s/check", "wait for", *service);
	return 0;
	}
	return WEXITSTATUS(w) == 0;
	}

	static int check(const char *a)
	{
	int r;
	unsigned pid_le32;
	uint64_t timestamp;

	r = svstatus_get();
	if (r == -1)
	return -1;
	if (r == 0) {
	if (*a == 'x')
	return 1;
	return -1;
	}
	pid_le32 = svstatus.pid_le32;
	switch (*a) {
	case 'x':
	return 0;
	case 'u':
	if (!pid_le32 \|\| svstatus.run_or_finish != 1) return 0;
	if (!checkscript()) return 0;
	break;
	case 'd':
	if (pid_le32) return 0;
	break;
	case 'c':
	if (pid_le32 && !checkscript()) return 0;
	break;
	case 't':
	if (!pid_le32 && svstatus.want == 'd') break;
	timestamp = SWAP_BE64(svstatus.time_be64);
	if ((tstart > timestamp) \|\| !pid_le32 \|\| svstatus.got_term \|\| !checkscript())
	return 0;
	break;
	case 'o':
	timestamp = SWAP_BE64(svstatus.time_be64);
	if ((!pid_le32 && tstart > timestamp) \|\| (pid_le32 && svstatus.want != 'd'))
	return 0;
	}
	printf(OK);
	svstatus_print(*service);
	bb_putchar('\n'); /* will also flush the output */
	return 1;
	}

	static int control(const char *a)
	{
	int fd, r, l;

	/* Is it an optimization?
	It causes problems with "sv o SRV; ...; sv d SRV"
	('d' is not passed to SRV because its .want == 'd'):
	if (svstatus_get() <= 0)
	return -1;
	if (svstatus.want == *a)
	return 0;
	*/
	fd = open("supervise/control", O_WRONLY\|O_NDELAY);
	if (fd == -1) {
	if (errno != ENODEV)
	warn("can't open supervise/control");
	else
	*a == 'x' ? ok("runsv not running") : failx("runsv not running");
	return -1;
	}
	l = strlen(a);
	r = write(fd, a, l);
	close(fd);
	if (r != l) {
	warn("can't write to supervise/control");
	return -1;
	}
	return 1;
	}

	int sv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int sv_main(int argc UNUSED_PARAM, char **argv)
	{
	char *x;
	char *action;
	const char *varservice = CONFIG_SV_DEFAULT_SERVICE_DIR;
	unsigned waitsec = 7;
	smallint kll = 0;
	int verbose = 0;
	int (act)(const char);
	int (cbk)(const char);
	int curdir;

	INIT_G();

	xfunc_error_retval = 100;

	x = getenv("SVDIR");
	if (x) varservice = x;
	x = getenv("SVWAIT");
	if (x) waitsec = xatou(x);

	opt_complementary = "w+:vv"; /* -w N, -v is a counter */
	getopt32(argv, "w:v", &waitsec, &verbose);
	argv += optind;
	action = *argv++;
	if (!action \|\| !*argv) bb_show_usage();

	tnow = time(NULL) + 0x400000000000000aULL;
	tstart = tnow;
	curdir = open(".", O_RDONLY\|O_NDELAY);
	if (curdir == -1)
	fatal_cannot("open current directory");

	act = &control;
	acts = "s";
	cbk = &check;

	switch (*action) {
	case 'x':
	case 'e':
	acts = "x";
	if (!verbose) cbk = NULL;
	break;
	case 'X':
	case 'E':
	acts = "x";
	kll = 1;
	break;
	case 'D':
	acts = "d";
	kll = 1;
	break;
	case 'T':
	acts = "tc";
	kll = 1;
	break;
	case 'c':
	if (str_equal(action, "check")) {
	act = NULL;
	acts = "c";
	break;
	}
	case 'u': case 'd': case 'o': case 't': case 'p': case 'h':
	case 'a': case 'i': case 'k': case 'q': case '1': case '2':
	action[1] = '\0';
	acts = action;
	if (!verbose) cbk = NULL;
	break;
	case 's':
	if (str_equal(action, "shutdown")) {
	acts = "x";
	break;
	}
	if (str_equal(action, "start")) {
	acts = "u";
	break;
	}
	if (str_equal(action, "stop")) {
	acts = "d";
	break;
	}
	/* "status" */
	act = &status;
	cbk = NULL;
	break;
	case 'r':
	if (str_equal(action, "restart")) {
	acts = "tcu";
	break;
	}
	bb_show_usage();
	case 'f':
	if (str_equal(action, "force-reload")) {
	acts = "tc";
	kll = 1;
	break;
	}
	if (str_equal(action, "force-restart")) {
	acts = "tcu";
	kll = 1;
	break;
	}
	if (str_equal(action, "force-shutdown")) {
	acts = "x";
	kll = 1;
	break;
	}
	if (str_equal(action, "force-stop")) {
	acts = "d";
	kll = 1;
	break;
	}
	default:
	bb_show_usage();
	}

	service = argv;
	while ((x = *service) != NULL) {
	if (x[0] != '/' && x[0] != '.') {
	if (chdir(varservice) == -1)
	goto chdir_failed_0;
	}
	if (chdir(x) == -1) {
	chdir_failed_0:
	fail("can't change to service directory");
	goto nullify_service_0;
	}
	if (act && (act(acts) == -1)) {
	nullify_service_0:
	service = (char) -1L; /* "dead" */
	}
	if (fchdir(curdir) == -1)
	fatal_cannot("change to original directory");
	service++;
	}

	if (cbk) while (1) {
	int want_exit;
	int diff;

	diff = tnow - tstart;
	service = argv;
	want_exit = 1;
	while ((x = *service) != NULL) {
	if (x == (char) -1L) / "dead" */
	goto next;
	if (x[0] != '/' && x[0] != '.') {
	if (chdir(varservice) == -1)
	goto chdir_failed;
	}
	if (chdir(x) == -1) {
	chdir_failed:
	fail("can't change to service directory");
	goto nullify_service;
	}
	if (cbk(acts) != 0)
	goto nullify_service;
	want_exit = 0;
	if (diff >= waitsec) {
	printf(kll ? "kill: " : "timeout: ");
	if (svstatus_get() > 0) {
	svstatus_print(x);
	++rc;
	}
	bb_putchar('\n'); /* will also flush the output */
	if (kll)
	control("k");
	nullify_service:
	service = (char) -1L; /* "dead" */
	}
	if (fchdir(curdir) == -1)
	fatal_cannot("change to original directory");
	next:
	service++;
	}
	if (want_exit) break;
	usleep(420000);
	tnow = time(NULL) + 0x400000000000000aULL;
	}
	return rc > 99 ? 99 : rc;
	}