[mirror_frr.git] / lib / zlog_live.c

/*
 * Copyright (c) 2019-22  David Lamparter, for NetDEF, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "zebra.h"

#include "zlog_live.h"

#include "memory.h"
#include "frrcu.h"
#include "zlog.h"
#include "printfrr.h"
#include "network.h"

DEFINE_MTYPE_STATIC(LOG, LOG_LIVE, "log vtysh live target");

enum {
	STATE_NORMAL = 0,
	STATE_FD_DEAD,
	STATE_DISOWNED,
};

struct zlt_live {
	struct zlog_target zt;

	atomic_uint_fast32_t fd;
	struct rcu_head_close head_close;
	struct rcu_head head_self;

	atomic_uint_fast32_t state;
};

static void zlog_live(struct zlog_target *zt, struct zlog_msg *msgs[],
		      size_t nmsgs)
{
	struct zlt_live *zte = container_of(zt, struct zlt_live, zt);
	struct zlog_live_hdr hdrs[nmsgs], *hdr = hdrs;
	struct mmsghdr mmhs[nmsgs], *mmh = mmhs;
	struct iovec iovs[nmsgs * 3], *iov = iovs;
	struct timespec ts;
	size_t i, textlen;
	int fd;
	uint_fast32_t state;

	fd = atomic_load_explicit(&zte->fd, memory_order_relaxed);

	if (fd < 0)
		return;

	memset(mmhs, 0, sizeof(mmhs));
	memset(hdrs, 0, sizeof(hdrs));

	for (i = 0; i < nmsgs; i++) {
		const struct fmt_outpos *argpos;
		size_t n_argpos, texthdrlen;
		struct zlog_msg *msg = msgs[i];
		int prio = zlog_msg_prio(msg);
		const struct xref_logmsg *xref;
		intmax_t pid, tid;

		if (prio > zt->prio_min)
			continue;

		zlog_msg_args(msg, &texthdrlen, &n_argpos, &argpos);

		mmh->msg_hdr.msg_iov = iov;

		iov->iov_base = hdr;
		iov->iov_len = sizeof(*hdr);
		iov++;

		if (n_argpos) {
			iov->iov_base = (char *)argpos;
			iov->iov_len = sizeof(*argpos) * n_argpos;
			iov++;
		}

		iov->iov_base = (char *)zlog_msg_text(msg, &textlen);
		iov->iov_len = textlen;
		iov++;

		zlog_msg_tsraw(msg, &ts);
		zlog_msg_pid(msg, &pid, &tid);
		xref = zlog_msg_xref(msg);

		hdr->ts_sec = ts.tv_sec;
		hdr->ts_nsec = ts.tv_nsec;
		hdr->pid = pid;
		hdr->tid = tid;
		hdr->prio = prio;
		hdr->flags = 0;
		hdr->textlen = textlen;
		hdr->texthdrlen = texthdrlen;
		hdr->n_argpos = n_argpos;
		if (xref) {
			memcpy(hdr->uid, xref->xref.xrefdata->uid,
			       sizeof(hdr->uid));
			hdr->ec = xref->ec;
		} else {
			memset(hdr->uid, 0, sizeof(hdr->uid));
			hdr->ec = 0;
		}
		hdr->hdrlen = sizeof(*hdr) + sizeof(*argpos) * n_argpos;

		mmh->msg_hdr.msg_iovlen = iov - mmh->msg_hdr.msg_iov;
		mmh++;
		hdr++;
	}

	size_t msgtotal = mmh - mmhs;
	ssize_t sent;

	for (size_t msgpos = 0; msgpos < msgtotal; msgpos += sent) {
		sent = sendmmsg(fd, mmhs + msgpos, msgtotal - msgpos, 0);

		if (sent <= 0 && (errno == EAGAIN || errno == EWOULDBLOCK))
			break;
		if (sent <= 0)
			goto out_err;
	}
	return;

out_err:
	fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed);
	if (fd < 0)
		return;

	rcu_close(&zte->head_close, fd);
	zlog_target_replace(zt, NULL);

	state = STATE_NORMAL;
	atomic_compare_exchange_strong_explicit(
		&zte->state, &state, STATE_FD_DEAD, memory_order_relaxed,
		memory_order_relaxed);
	if (state == STATE_DISOWNED)
		rcu_free(MTYPE_LOG_LIVE, zte, head_self);
}

static void zlog_live_sigsafe(struct zlog_target *zt, const char *text,
			      size_t len)
{
	struct zlt_live *zte = container_of(zt, struct zlt_live, zt);
	struct zlog_live_hdr hdr[1] = {};
	struct iovec iovs[2], *iov = iovs;
	struct timespec ts;
	int fd;

	fd = atomic_load_explicit(&zte->fd, memory_order_relaxed);
	if (fd < 0)
		return;

	clock_gettime(CLOCK_REALTIME, &ts);

	hdr->ts_sec = ts.tv_sec;
	hdr->ts_nsec = ts.tv_nsec;
	hdr->prio = LOG_CRIT;
	hdr->textlen = len;

	iov->iov_base = (char *)hdr;
	iov->iov_len = sizeof(hdr);
	iov++;

	iov->iov_base = (char *)text;
	iov->iov_len = len;
	iov++;

	writev(fd, iovs, iov - iovs);
}

void zlog_live_open(struct zlog_live_cfg *cfg, int prio_min, int *other_fd)
{
	int sockets[2];
	struct zlt_live *zte;
	struct zlog_target *zt;

	if (cfg->target)
		zlog_live_close(cfg);

	*other_fd = -1;
	if (prio_min == ZLOG_DISABLED)
		return;

	/* the only reason for SEQPACKET here is getting close notifications.
	 * otherwise if you open a bunch of vtysh connections with live logs
	 * and close them all, the fds will stick around until we get an error
	 * when trying to log something to them at some later point -- which
	 * eats up fds and might be *much* later for some daemons.
	 */
	if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) < 0) {
		if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sockets) < 0) {
			zlog_warn("%% could not open socket pair: %m");
			return;
		}
	} else
		/* SEQPACKET only: try to zap read direction */
		shutdown(sockets[0], SHUT_RD);

	*other_fd = sockets[1];

	zt = zlog_target_clone(MTYPE_LOG_LIVE, NULL, sizeof(*zte));
	zte = container_of(zt, struct zlt_live, zt);
	cfg->target = zte;

	set_nonblocking(sockets[0]);
	zte->fd = sockets[0];
	zte->zt.prio_min = prio_min;
	zte->zt.logfn = zlog_live;
	zte->zt.logfn_sigsafe = zlog_live_sigsafe;

	zlog_target_replace(NULL, zt);
}

void zlog_live_close(struct zlog_live_cfg *cfg)
{
	struct zlt_live *zte;
	int fd;

	if (!cfg->target)
		return;

	zte = cfg->target;
	cfg->target = NULL;

	fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed);

	if (fd >= 0) {
		rcu_close(&zte->head_close, fd);
		zlog_target_replace(&zte->zt, NULL);
	}
	rcu_free(MTYPE_LOG_LIVE, zte, head_self);
}

void zlog_live_disown(struct zlog_live_cfg *cfg)
{
	struct zlt_live *zte;
	uint_fast32_t state;

	if (!cfg->target)
		return;

	zte = cfg->target;
	cfg->target = NULL;

	state = STATE_NORMAL;
	atomic_compare_exchange_strong_explicit(
		&zte->state, &state, STATE_DISOWNED, memory_order_relaxed,
		memory_order_relaxed);
	if (state == STATE_FD_DEAD)
		rcu_free(MTYPE_LOG_LIVE, zte, head_self);
}
Commit	Line	Data
0798d276 DL	1	/*
	2	* Copyright (c) 2019-22 David Lamparter, for NetDEF, Inc.
	3	*
	4	* Permission to use, copy, modify, and distribute this software for any
	5	* purpose with or without fee is hereby granted, provided that the above
	6	* copyright notice and this permission notice appear in all copies.
	7	*
	8	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	9	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	10	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	11	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	12	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	13	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	14	* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	15	*/
	16
	17	#include "zebra.h"
	18
	19	#include "zlog_live.h"
	20
	21	#include "memory.h"
	22	#include "frrcu.h"
	23	#include "zlog.h"
	24	#include "printfrr.h"
2eda953a	25	#include "network.h"
0798d276 DL	26
	27	DEFINE_MTYPE_STATIC(LOG, LOG_LIVE, "log vtysh live target");
	28
	29	enum {
	30	STATE_NORMAL = 0,
	31	STATE_FD_DEAD,
	32	STATE_DISOWNED,
	33	};
	34
	35	struct zlt_live {
	36	struct zlog_target zt;
	37
	38	atomic_uint_fast32_t fd;
	39	struct rcu_head_close head_close;
	40	struct rcu_head head_self;
	41
	42	atomic_uint_fast32_t state;
	43	};
	44
	45	static void zlog_live(struct zlog_target zt, struct zlog_msg msgs[],
	46	size_t nmsgs)
	47	{
	48	struct zlt_live *zte = container_of(zt, struct zlt_live, zt);
	49	struct zlog_live_hdr hdrs[nmsgs], *hdr = hdrs;
	50	struct mmsghdr mmhs[nmsgs], *mmh = mmhs;
	51	struct iovec iovs[nmsgs * 3], *iov = iovs;
	52	struct timespec ts;
	53	size_t i, textlen;
	54	int fd;
	55	uint_fast32_t state;
	56
	57	fd = atomic_load_explicit(&zte->fd, memory_order_relaxed);
	58
	59	if (fd < 0)
	60	return;
	61
	62	memset(mmhs, 0, sizeof(mmhs));
	63	memset(hdrs, 0, sizeof(hdrs));
	64
	65	for (i = 0; i < nmsgs; i++) {
	66	const struct fmt_outpos *argpos;
834585bd	67	size_t n_argpos, texthdrlen;
0798d276 DL	68	struct zlog_msg *msg = msgs[i];
0798d276 DL	69	int prio = zlog_msg_prio(msg);
834585bd DL	70	const struct xref_logmsg *xref;
834585bd DL	71	intmax_t pid, tid;
0798d276 DL	72
	73	if (prio > zt->prio_min)
	74	continue;
	75
834585bd	76	zlog_msg_args(msg, &texthdrlen, &n_argpos, &argpos);
0798d276 DL	77
	78	mmh->msg_hdr.msg_iov = iov;
	79
	80	iov->iov_base = hdr;
	81	iov->iov_len = sizeof(*hdr);
	82	iov++;
	83
	84	if (n_argpos) {
	85	iov->iov_base = (char *)argpos;
	86	iov->iov_len = sizeof(argpos) n_argpos;
	87	iov++;
	88	}
	89
	90	iov->iov_base = (char *)zlog_msg_text(msg, &textlen);
	91	iov->iov_len = textlen;
	92	iov++;
	93
	94	zlog_msg_tsraw(msg, &ts);
834585bd DL	95	zlog_msg_pid(msg, &pid, &tid);
834585bd DL	96	xref = zlog_msg_xref(msg);
0798d276 DL	97
	98	hdr->ts_sec = ts.tv_sec;
	99	hdr->ts_nsec = ts.tv_nsec;
834585bd DL	100	hdr->pid = pid;
	101	hdr->tid = tid;
	102	hdr->prio = prio;
0798d276 DL	103	hdr->flags = 0;
0798d276 DL	104	hdr->textlen = textlen;
834585bd	105	hdr->texthdrlen = texthdrlen;
0798d276	106	hdr->n_argpos = n_argpos;
834585bd DL	107	if (xref) {
	108	memcpy(hdr->uid, xref->xref.xrefdata->uid,
	109	sizeof(hdr->uid));
	110	hdr->ec = xref->ec;
	111	} else {
	112	memset(hdr->uid, 0, sizeof(hdr->uid));
	113	hdr->ec = 0;
	114	}
	115	hdr->hdrlen = sizeof(hdr) + sizeof(argpos) * n_argpos;
0798d276 DL	116
	117	mmh->msg_hdr.msg_iovlen = iov - mmh->msg_hdr.msg_iov;
	118	mmh++;
	119	hdr++;
	120	}
	121
	122	size_t msgtotal = mmh - mmhs;
	123	ssize_t sent;
	124
	125	for (size_t msgpos = 0; msgpos < msgtotal; msgpos += sent) {
	126	sent = sendmmsg(fd, mmhs + msgpos, msgtotal - msgpos, 0);
	127
2eda953a DL	128	if (sent <= 0 && (errno == EAGAIN \|\| errno == EWOULDBLOCK))
2eda953a DL	129	break;
0798d276 DL	130	if (sent <= 0)
	131	goto out_err;
	132	}
	133	return;
	134
	135	out_err:
	136	fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed);
	137	if (fd < 0)
	138	return;
	139
	140	rcu_close(&zte->head_close, fd);
	141	zlog_target_replace(zt, NULL);
	142
	143	state = STATE_NORMAL;
	144	atomic_compare_exchange_strong_explicit(
	145	&zte->state, &state, STATE_FD_DEAD, memory_order_relaxed,
	146	memory_order_relaxed);
	147	if (state == STATE_DISOWNED)
	148	rcu_free(MTYPE_LOG_LIVE, zte, head_self);
	149	}
	150
	151	static void zlog_live_sigsafe(struct zlog_target zt, const char text,
	152	size_t len)
	153	{
	154	struct zlt_live *zte = container_of(zt, struct zlt_live, zt);
1609a9d6	155	struct zlog_live_hdr hdr[1] = {};
0798d276 DL	156	struct iovec iovs[2], *iov = iovs;
	157	struct timespec ts;
	158	int fd;
	159
	160	fd = atomic_load_explicit(&zte->fd, memory_order_relaxed);
	161	if (fd < 0)
	162	return;
	163
1609a9d6	164	clock_gettime(CLOCK_REALTIME, &ts);
0798d276 DL	165
	166	hdr->ts_sec = ts.tv_sec;
	167	hdr->ts_nsec = ts.tv_nsec;
	168	hdr->prio = LOG_CRIT;
0798d276	169	hdr->textlen = len;
0798d276 DL	170
	171	iov->iov_base = (char *)hdr;
	172	iov->iov_len = sizeof(hdr);
	173	iov++;
	174
	175	iov->iov_base = (char *)text;
	176	iov->iov_len = len;
	177	iov++;
	178
	179	writev(fd, iovs, iov - iovs);
	180	}
	181
	182	void zlog_live_open(struct zlog_live_cfg cfg, int prio_min, int other_fd)
	183	{
	184	int sockets[2];
	185	struct zlt_live *zte;
	186	struct zlog_target *zt;
	187
	188	if (cfg->target)
	189	zlog_live_close(cfg);
	190
	191	*other_fd = -1;
	192	if (prio_min == ZLOG_DISABLED)
	193	return;
	194
	195	/* the only reason for SEQPACKET here is getting close notifications.
	196	* otherwise if you open a bunch of vtysh connections with live logs
	197	* and close them all, the fds will stick around until we get an error
	198	* when trying to log something to them at some later point -- which
	199	* eats up fds and might be much later for some daemons.
	200	*/
	201	if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) < 0) {
	202	if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sockets) < 0) {
	203	zlog_warn("%% could not open socket pair: %m");
	204	return;
	205	}
	206	} else
	207	/* SEQPACKET only: try to zap read direction */
	208	shutdown(sockets[0], SHUT_RD);
	209
	210	*other_fd = sockets[1];
	211
	212	zt = zlog_target_clone(MTYPE_LOG_LIVE, NULL, sizeof(*zte));
	213	zte = container_of(zt, struct zlt_live, zt);
	214	cfg->target = zte;
	215
2eda953a	216	set_nonblocking(sockets[0]);
0798d276 DL	217	zte->fd = sockets[0];
	218	zte->zt.prio_min = prio_min;
	219	zte->zt.logfn = zlog_live;
	220	zte->zt.logfn_sigsafe = zlog_live_sigsafe;
	221
	222	zlog_target_replace(NULL, zt);
	223	}
	224
	225	void zlog_live_close(struct zlog_live_cfg *cfg)
	226	{
	227	struct zlt_live *zte;
	228	int fd;
	229
	230	if (!cfg->target)
	231	return;
	232
	233	zte = cfg->target;
	234	cfg->target = NULL;
	235
	236	fd = atomic_exchange_explicit(&zte->fd, -1, memory_order_relaxed);
	237
	238	if (fd >= 0) {
	239	rcu_close(&zte->head_close, fd);
	240	zlog_target_replace(&zte->zt, NULL);
	241	}
	242	rcu_free(MTYPE_LOG_LIVE, zte, head_self);
	243	}
	244
	245	void zlog_live_disown(struct zlog_live_cfg *cfg)
	246	{
	247	struct zlt_live *zte;
	248	uint_fast32_t state;
	249
	250	if (!cfg->target)
	251	return;
	252
	253	zte = cfg->target;
	254	cfg->target = NULL;
	255
	256	state = STATE_NORMAL;
	257	atomic_compare_exchange_strong_explicit(
	258	&zte->state, &state, STATE_DISOWNED, memory_order_relaxed,
	259	memory_order_relaxed);
	260	if (state == STATE_FD_DEAD)
	261	rcu_free(MTYPE_LOG_LIVE, zte, head_self);
	262	}