lib: vty_stdio signal handling

[mirror_frr.git] / lib / libfrr.c

/*
 * libfrr overall management functions
 *
 * Copyright (C) 2016  David Lamparter for NetDEF, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#include <sys/types.h>
#include <sys/wait.h>

#include "libfrr.h"
#include "getopt.h"
#include "vty.h"
#include "command.h"
#include "version.h"
#include "memory_vty.h"
#include "zclient.h"
#include "log_int.h"
#include "module.h"
#include "network.h"

DEFINE_HOOK(frr_late_init, (struct thread_master * tm), (tm))

const char frr_sysconfdir[] = SYSCONFDIR;
const char frr_vtydir[] = DAEMON_VTY_DIR;
const char frr_moduledir[] = MODULE_PATH;

char frr_protoname[256] = "NONE";
char frr_protonameinst[256] = "NONE";

char config_default[256];
static char pidfile_default[256];
static char vtypath_default[256];

static char comb_optstr[256];
static struct option comb_lo[64];
static struct option *comb_next_lo = &comb_lo[0];
static char comb_helpstr[4096];

struct optspec {
	const char *optstr;
	const char *helpstr;
	const struct option *longopts;
};

static void opt_extend(const struct optspec *os)
{
	const struct option *lo;

	strcat(comb_optstr, os->optstr);
	strcat(comb_helpstr, os->helpstr);
	for (lo = os->longopts; lo->name; lo++)
		memcpy(comb_next_lo++, lo, sizeof(*lo));
}


#define OPTION_VTYSOCK   1000
#define OPTION_MODULEDIR 1002

static const struct option lo_always[] = {
	{"help", no_argument, NULL, 'h'},
	{"version", no_argument, NULL, 'v'},
	{"daemon", no_argument, NULL, 'd'},
	{"module", no_argument, NULL, 'M'},
	{"vty_socket", required_argument, NULL, OPTION_VTYSOCK},
	{"moduledir", required_argument, NULL, OPTION_MODULEDIR},
	{NULL}};
static const struct optspec os_always = {
	"hvdM:",
	"  -h, --help         Display this help and exit\n"
	"  -v, --version      Print program version\n"
	"  -d, --daemon       Runs in daemon mode\n"
	"  -M, --module       Load specified module\n"
	"      --vty_socket   Override vty socket path\n"
	"      --moduledir    Override modules directory\n",
	lo_always};


static const struct option lo_cfg_pid_dry[] = {
	{"pid_file", required_argument, NULL, 'i'},
	{"config_file", required_argument, NULL, 'f'},
	{"dryrun", no_argument, NULL, 'C'},
	{"terminal", no_argument, NULL, 't'},
	{NULL}};
static const struct optspec os_cfg_pid_dry = {
	"f:i:Ct",
	"  -f, --config_file  Set configuration file name\n"
	"  -i, --pid_file     Set process identifier file name\n"
	"  -C, --dryrun       Check configuration for validity and exit\n"
	"  -t, --terminal     Open terminal session on stdio\n"
	"  -d -t              Daemonize after terminal session ends\n",
	lo_cfg_pid_dry};


static const struct option lo_zclient[] = {
	{"socket", required_argument, NULL, 'z'},
	{NULL}};
static const struct optspec os_zclient = {
	"z:", "  -z, --socket       Set path of zebra socket\n", lo_zclient};


static const struct option lo_vty[] = {
	{"vty_addr", required_argument, NULL, 'A'},
	{"vty_port", required_argument, NULL, 'P'},
	{NULL}};
static const struct optspec os_vty = {
	"A:P:",
	"  -A, --vty_addr     Set vty's bind address\n"
	"  -P, --vty_port     Set vty's port number\n",
	lo_vty};


static const struct option lo_user[] = {{"user", required_argument, NULL, 'u'},
					{"group", required_argument, NULL, 'g'},
					{NULL}};
static const struct optspec os_user = {"u:g:",
				       "  -u, --user         User to run as\n"
				       "  -g, --group        Group to run as\n",
				       lo_user};


static struct frr_daemon_info *di = NULL;

void frr_preinit(struct frr_daemon_info *daemon, int argc, char **argv)
{
	di = daemon;

	/* basename(), opencoded. */
	char *p = strrchr(argv[0], '/');
	di->progname = p ? p + 1 : argv[0];

	umask(0027);

	opt_extend(&os_always);
	if (!(di->flags & FRR_NO_CFG_PID_DRY))
		opt_extend(&os_cfg_pid_dry);
	if (!(di->flags & FRR_NO_PRIVSEP))
		opt_extend(&os_user);
	if (!(di->flags & FRR_NO_ZCLIENT))
		opt_extend(&os_zclient);
	if (!(di->flags & FRR_NO_TCPVTY))
		opt_extend(&os_vty);

	snprintf(config_default, sizeof(config_default), "%s/%s.conf",
		 frr_sysconfdir, di->name);
	snprintf(pidfile_default, sizeof(pidfile_default), "%s/%s.pid",
		 frr_vtydir, di->name);

	strlcpy(frr_protoname, di->logname, sizeof(frr_protoname));
	strlcpy(frr_protonameinst, di->logname, sizeof(frr_protonameinst));
}

void frr_opt_add(const char *optstr, const struct option *longopts,
		 const char *helpstr)
{
	const struct optspec main_opts = {optstr, helpstr, longopts};
	opt_extend(&main_opts);
}

void frr_help_exit(int status)
{
	FILE *target = status ? stderr : stdout;

	if (status != 0)
		fprintf(stderr, "Invalid options.\n\n");

	if (di->printhelp)
		di->printhelp(target);
	else
		fprintf(target, "Usage: %s [OPTION...]\n\n%s%s%s\n\n%s",
			di->progname, di->proghelp, di->copyright ? "\n\n" : "",
			di->copyright ? di->copyright : "", comb_helpstr);
	fprintf(target, "\nReport bugs to %s\n", FRR_BUG_ADDRESS);
	exit(status);
}

struct option_chain {
	struct option_chain *next;
	const char *arg;
};

static struct option_chain *modules = NULL, **modnext = &modules;
static int errors = 0;

static int frr_opt(int opt)
{
	static int vty_port_set = 0;
	static int vty_addr_set = 0;
	struct option_chain *oc;
	char *err;

	switch (opt) {
	case 'h':
		frr_help_exit(0);
		break;
	case 'v':
		print_version(di->progname);
		exit(0);
		break;
	case 'd':
		di->daemon_mode = 1;
		break;
	case 'M':
		oc = XMALLOC(MTYPE_TMP, sizeof(*oc));
		oc->arg = optarg;
		oc->next = NULL;
		*modnext = oc;
		modnext = &oc->next;
		break;
	case 'i':
		if (di->flags & FRR_NO_CFG_PID_DRY)
			return 1;
		di->pid_file = optarg;
		break;
	case 'f':
		if (di->flags & FRR_NO_CFG_PID_DRY)
			return 1;
		di->config_file = optarg;
		break;
	case 'C':
		if (di->flags & FRR_NO_CFG_PID_DRY)
			return 1;
		di->dryrun = 1;
		break;
	case 't':
		if (di->flags & FRR_NO_CFG_PID_DRY)
			return 1;
		di->terminal = 1;
		break;
	case 'z':
		if (di->flags & FRR_NO_ZCLIENT)
			return 1;
		zclient_serv_path_set(optarg);
		break;
	case 'A':
		if (di->flags & FRR_NO_TCPVTY)
			return 1;
		if (vty_addr_set) {
			fprintf(stderr,
				"-A option specified more than once!\n");
			errors++;
			break;
		}
		vty_addr_set = 1;
		di->vty_addr = optarg;
		break;
	case 'P':
		if (di->flags & FRR_NO_TCPVTY)
			return 1;
		if (vty_port_set) {
			fprintf(stderr,
				"-P option specified more than once!\n");
			errors++;
			break;
		}
		vty_port_set = 1;
		di->vty_port = strtoul(optarg, &err, 0);
		if (*err || !*optarg) {
			fprintf(stderr,
				"invalid port number \"%s\" for -P option\n",
				optarg);
			errors++;
			break;
		}
		break;
	case OPTION_VTYSOCK:
		if (di->vty_sock_path) {
			fprintf(stderr,
				"--vty_socket option specified more than once!\n");
			errors++;
			break;
		}
		di->vty_sock_path = optarg;
		break;
	case OPTION_MODULEDIR:
		if (di->module_path) {
			fprintf(stderr,
				"----moduledir option specified more than once!\n");
			errors++;
			break;
		}
		di->module_path = optarg;
		break;
	case 'u':
		if (di->flags & FRR_NO_PRIVSEP)
			return 1;
		di->privs->user = optarg;
		break;
	case 'g':
		if (di->flags & FRR_NO_PRIVSEP)
			return 1;
		di->privs->group = optarg;
		break;
	default:
		return 1;
	}
	return 0;
}

int frr_getopt(int argc, char *const argv[], int *longindex)
{
	int opt;
	int lidx;

	comb_next_lo->name = NULL;

	do {
		opt = getopt_long(argc, argv, comb_optstr, comb_lo, &lidx);
		if (frr_opt(opt))
			break;
	} while (opt != -1);

	if (opt == -1 && errors)
		frr_help_exit(1);
	if (longindex)
		*longindex = lidx;
	return opt;
}

static struct thread_master *master;
struct thread_master *frr_init(void)
{
	struct option_chain *oc;
	struct frrmod_runtime *module;
	char moderr[256];
	const char *dir;
	dir = di->module_path ? di->module_path : frr_moduledir;

	srandom(time(NULL));

	if (di->instance)
		snprintf(frr_protonameinst, sizeof(frr_protonameinst), "%s[%u]",
			 di->logname, di->instance);

	openzlog(di->progname, di->logname, di->instance,
		 LOG_CONS | LOG_NDELAY | LOG_PID, LOG_DAEMON);
#if defined(HAVE_CUMULUS)
	zlog_set_level(ZLOG_DEST_SYSLOG, zlog_default->default_lvl);
#endif

	frrmod_init(di->module);
	while (modules) {
		modules = (oc = modules)->next;
		module = frrmod_load(oc->arg, dir, moderr, sizeof(moderr));
		if (!module) {
			fprintf(stderr, "%s\n", moderr);
			exit(1);
		}
		XFREE(MTYPE_TMP, oc);
	}

	zprivs_init(di->privs);

	master = thread_master_create(NULL);
	signal_init(master, di->n_signals, di->signals);

	if (di->flags & FRR_LIMITED_CLI)
		cmd_init(-1);
	else
		cmd_init(1);
	vty_init(master);
	memory_init();

	return master;
}

static int rcvd_signal = 0;

static void rcv_signal(int signum)
{
	rcvd_signal = signum;
	/* poll() is interrupted by the signal; handled below */
}

static void frr_daemon_wait(int fd)
{
	struct pollfd pfd[1];
	int ret;
	pid_t exitpid;
	int exitstat;
	sigset_t sigs, prevsigs;

	sigemptyset(&sigs);
	sigaddset(&sigs, SIGTSTP);
	sigaddset(&sigs, SIGQUIT);
	sigaddset(&sigs, SIGINT);
	sigprocmask(SIG_BLOCK, &sigs, &prevsigs);

	struct sigaction sa = {
		.sa_handler = rcv_signal, .sa_flags = SA_RESETHAND,
	};
	sigemptyset(&sa.sa_mask);
	sigaction(SIGTSTP, &sa, NULL);
	sigaction(SIGQUIT, &sa, NULL);
	sigaction(SIGINT, &sa, NULL);

	do {
		char buf[1];
		ssize_t nrecv;

		pfd[0].fd = fd;
		pfd[0].events = POLLIN;

		rcvd_signal = 0;

#if   defined(HAVE_PPOLL)
		ret = ppoll(pfd, 1, NULL, &prevsigs);
#elif defined(HAVE_POLLTS)
		ret = pollts(pfd, 1, NULL, &prevsigs);
#else
		/* racy -- only used on FreeBSD 9 */
		sigset_t tmpsigs;
		sigprocmask(SIG_SETMASK, &prevsigs, &tmpsigs);
		ret = poll(pfd, 1, -1);
		sigprocmask(SIG_SETMASK, &tmpsigs, NULL);
#endif
		if (ret < 0 && errno != EINTR && errno != EAGAIN) {
			perror("poll()");
			exit(1);
		}
		switch (rcvd_signal) {
		case SIGTSTP:
			send(fd, "S", 1, 0);
			do {
				nrecv = recv(fd, buf, sizeof(buf), 0);
			} while (nrecv == -1
				 && (errno == EINTR || errno == EAGAIN));

			raise(SIGTSTP);
			sigaction(SIGTSTP, &sa, NULL);
			send(fd, "R", 1, 0);
			break;
		case SIGINT:
			send(fd, "I", 1, 0);
			break;
		case SIGQUIT:
			send(fd, "Q", 1, 0);
			break;
		}
	} while (ret <= 0);

	exitpid = waitpid(-1, &exitstat, WNOHANG);
	if (exitpid == 0)
		/* child successfully went to main loop & closed socket */
		exit(0);

	/* child failed one way or another ... */
	if (WIFEXITED(exitstat))
		fprintf(stderr, "%s failed to start, exited %d\n", di->name,
			WEXITSTATUS(exitstat));
	else if (WIFSIGNALED(exitstat))
		fprintf(stderr, "%s crashed in startup, signal %d\n", di->name,
			WTERMSIG(exitstat));
	else
		fprintf(stderr, "%s failed to start, unknown problem\n",
			di->name);
	exit(1);
}

static int daemon_ctl_sock = -1;

static void frr_daemonize(void)
{
	int fds[2];
	pid_t pid;

	if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds)) {
		perror("socketpair() for daemon control");
		exit(1);
	}
	set_cloexec(fds[0]);
	set_cloexec(fds[1]);

	pid = fork();
	if (pid < 0) {
		perror("fork()");
		exit(1);
	}
	if (pid == 0) {
		/* child */
		close(fds[0]);
		if (setsid() < 0) {
			perror("setsid()");
			exit(1);
		}

		daemon_ctl_sock = fds[1];
		return;
	}

	close(fds[1]);
	frr_daemon_wait(fds[0]);
}

void frr_config_fork(void)
{
	hook_call(frr_late_init, master);

	if (di->instance) {
		snprintf(config_default, sizeof(config_default),
			 "%s/%s-%d.conf", frr_sysconfdir, di->name,
			 di->instance);
		snprintf(pidfile_default, sizeof(pidfile_default),
			 "%s/%s-%d.pid", frr_vtydir, di->name, di->instance);
	}

	vty_read_config(di->config_file, config_default);

	/* Don't start execution if we are in dry-run mode */
	if (di->dryrun)
		exit(0);

	if (di->daemon_mode || di->terminal)
		frr_daemonize();

	if (!di->pid_file)
		di->pid_file = pidfile_default;
	pid_output(di->pid_file);
}

void frr_vty_serv(void)
{
	/* allow explicit override of vty_path in the future
	 * (not currently set anywhere) */
	if (!di->vty_path) {
		const char *dir;
		dir = di->vty_sock_path ? di->vty_sock_path : frr_vtydir;

		if (di->instance)
			snprintf(vtypath_default, sizeof(vtypath_default),
				 "%s/%s-%d.vty", dir, di->name, di->instance);
		else
			snprintf(vtypath_default, sizeof(vtypath_default),
				 "%s/%s.vty", dir, di->name);

		di->vty_path = vtypath_default;
	}

	vty_serv_sock(di->vty_addr, di->vty_port, di->vty_path);
}

static void frr_terminal_close(int isexit)
{
	if (daemon_ctl_sock != -1) {
		close(daemon_ctl_sock);
		daemon_ctl_sock = -1;
	}

	if (!di->daemon_mode || isexit) {
		printf("\n%s exiting\n", di->name);
		if (!isexit)
			raise(SIGINT);
		return;
	} else {
		printf("\n%s daemonizing\n", di->name);
		fflush(stdout);
	}

	int nullfd = open("/dev/null", O_RDONLY | O_NOCTTY);
	dup2(nullfd, 0);
	dup2(nullfd, 1);
	dup2(nullfd, 2);
	close(nullfd);
}

static struct thread *daemon_ctl_thread = NULL;

static int frr_daemon_ctl(struct thread *t)
{
	char buf[1];
	ssize_t nr;

	nr = recv(daemon_ctl_sock, buf, sizeof(buf), 0);
	if (nr < 0 && (errno == EINTR || errno == EAGAIN))
		goto out;
	if (nr <= 0)
		return 0;

	switch (buf[0]) {
	case 'S':	/* SIGTSTP */
		vty_stdio_suspend();
		send(daemon_ctl_sock, "s", 1, 0);
		break;
	case 'R':	/* SIGTCNT [implicit] */
		vty_stdio_resume();
		break;
	case 'I':	/* SIGINT */
		di->daemon_mode = false;
		raise(SIGINT);
		break;
	case 'Q':	/* SIGQUIT */
		di->daemon_mode = true;
		vty_stdio_close();
		break;
	}

out:
	thread_add_read(master, frr_daemon_ctl, NULL, daemon_ctl_sock,
			&daemon_ctl_thread);
	return 0;
}

void frr_run(struct thread_master *master)
{
	char instanceinfo[64] = "";

	frr_vty_serv();

	if (di->instance)
		snprintf(instanceinfo, sizeof(instanceinfo), "instance %u ",
			 di->instance);

	zlog_notice("%s %s starting: %svty@%d%s", di->name, FRR_VERSION,
		    instanceinfo, di->vty_port, di->startinfo);

	if (di->terminal) {
		vty_stdio(frr_terminal_close);
		if (daemon_ctl_sock != -1) {
			set_nonblocking(daemon_ctl_sock);
			thread_add_read(master, frr_daemon_ctl, NULL,
					daemon_ctl_sock, &daemon_ctl_thread);
		}
	} else if (daemon_ctl_sock != -1) {
		close(daemon_ctl_sock);
		daemon_ctl_sock = -1;
	}

	struct thread thread;
	while (thread_fetch(master, &thread))
		thread_call(&thread);
}