common/syslog-msgs/syslog.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/fm/protocol.h>
#include <sys/strlog.h>
#include <sys/log.h>

#include <fm/fmd_api.h>
#include <fm/fmd_msg.h>

#include <stropts.h>
#include <strings.h>
#include <syslog.h>
#include <alloca.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>

static struct stats {
	fmd_stat_t bad_vers;
	fmd_stat_t bad_code;
	fmd_stat_t log_err;
	fmd_stat_t msg_err;
	fmd_stat_t no_msg;
} syslog_stats = {
	{ "bad_vers", FMD_TYPE_UINT64, "event version is missing or invalid" },
	{ "bad_code", FMD_TYPE_UINT64, "event code has no dictionary name" },
	{ "log_err", FMD_TYPE_UINT64, "failed to log message to log(7D)" },
	{ "msg_err", FMD_TYPE_UINT64, "failed to log message to sysmsg(7D)" },
	{ "no_msg", FMD_TYPE_UINT64, "message logging suppressed" }
};

static const struct facility {
	const char *fac_name;
	int fac_value;
} syslog_facs[] = {
	{ "LOG_DAEMON", LOG_DAEMON },
	{ "LOG_LOCAL0", LOG_LOCAL0 },
	{ "LOG_LOCAL1", LOG_LOCAL1 },
	{ "LOG_LOCAL2", LOG_LOCAL2 },
	{ "LOG_LOCAL3", LOG_LOCAL3 },
	{ "LOG_LOCAL4", LOG_LOCAL4 },
	{ "LOG_LOCAL5", LOG_LOCAL5 },
	{ "LOG_LOCAL6", LOG_LOCAL6 },
	{ "LOG_LOCAL7", LOG_LOCAL7 },
	{ NULL, 0 }
};

static fmd_msg_hdl_t *syslog_msghdl; /* handle for libfmd_msg calls */
static int syslog_msgall;	/* set to message all faults */
static log_ctl_t syslog_ctl;	/* log(7D) meta-data for each msg */
static int syslog_logfd = -1;	/* log(7D) file descriptor */
static int syslog_msgfd = -1;	/* sysmsg(7D) file descriptor */
static int syslog_file;		/* log to syslog_logfd */
static int syslog_cons;		/* log to syslog_msgfd */
static const char SYSLOG_POINTER[] = "syslog-msgs-pointer";

/*
 * Ideally we would just use syslog(3C) for outputting our messages, but our
 * messaging standard defines a nice multi-line format and syslogd(1M) is very
 * inflexible and stupid when it comes to multi-line messages.  It pulls data
 * out of log(7D) and splits it up by \n, printing each line to the console
 * with its usual prefix of date and sender; it uses the same behavior for the
 * messages file as well.  Further, syslog(3C) provides no CE_CONT equivalent
 * for userland callers (which at least works around repeated file prefixing).
 * So with a multi-line message format, your file and console end up like this:
 *
 * Dec 02 18:08:40 hostname this is my nicely formatted
 * Dec 02 18:08:40 hostname message designed for 80 cols
 * ...
 *
 * To resolve these issues, we use our own syslog_emit() wrapper to emit
 * messages and some knowledge of how the Solaris log drivers work.  We first
 * construct an enlarged format string containing the appropriate msgid(1).
 * We then format the caller's message using the provided format and buffer.
 * We send this message to log(7D) using putmsg() with SL_CONSOLE | SL_LOGONLY
 * set in the log_ctl_t.  The log driver allows us to set SL_LOGONLY when we
 * construct messages ourself, indicating that syslogd should only emit the
 * message to /var/adm/messages and any remote hosts, and skip the console.
 * Then we emit the message a second time, without the special prefix, to the
 * sysmsg(7D) device, which handles console redirection and also permits us
 * to output any characters we like to the console, including \n and \r.
 */
static void
syslog_emit(fmd_hdl_t *hdl, const char *msg)
{
	struct strbuf ctl, dat;
	uint32_t msgid;

	char *buf;
	size_t buflen;

	const char *format = "fmd: [ID %u FACILITY_AND_PRIORITY] %s";
	STRLOG_MAKE_MSGID(format, msgid);

	buflen = snprintf(NULL, 0, format, msgid, msg);
	buf = alloca(buflen + 1);
	(void) snprintf(buf, buflen + 1, format, msgid, msg);

	ctl.buf = (void *)&syslog_ctl;
	ctl.len = sizeof (syslog_ctl);

	dat.buf = buf;
	dat.len = buflen + 1;

	/*
	 * The underlying log driver won't accept messages longer than
	 * LOG_MAXPS bytes.  Therefore, messages which exceed this limit will
	 * be truncated and appended with a pointer to the full message.
	 */
	if (dat.len > LOG_MAXPS) {
		char *syslog_pointer, *p;
		size_t plen;

		if ((syslog_pointer = fmd_msg_gettext_id(syslog_msghdl, NULL,
		    SYSLOG_POINTER)) == NULL) {
			/*
			 * This shouldn't happen, but if it does we'll just
			 * truncate the message.
			 */
			buf[LOG_MAXPS - 1] = '\0';
			dat.len = LOG_MAXPS;
		} else {
			plen = strlen(syslog_pointer) + 1;
			buf[LOG_MAXPS - plen] = '\0';
			/*
			 * If possible, the pointer is appended after a newline
			 */
			if ((p = strrchr(buf, '\n')) == NULL)
				p = &buf[LOG_MAXPS - plen];

			(void) strcpy(p, syslog_pointer);
			free(syslog_pointer);
			dat.len = strlen(buf) + 1;
		}
	}
	if (syslog_file && putmsg(syslog_logfd, &ctl, &dat, 0) != 0) {
		fmd_hdl_debug(hdl, "putmsg failed: %s\n", strerror(errno));
		syslog_stats.log_err.fmds_value.ui64++;
	}

	dat.buf = strchr(buf, ']');
	dat.len -= (size_t)(dat.buf - buf);

	dat.buf[0] = '\r'; /* overwrite ']' with carriage return */
	dat.buf[1] = '\n'; /* overwrite ' ' with newline */

	if (syslog_cons && write(syslog_msgfd, dat.buf, dat.len) != dat.len) {
		fmd_hdl_debug(hdl, "write failed: %s\n", strerror(errno));
		syslog_stats.msg_err.fmds_value.ui64++;
	}
}

/*ARGSUSED*/
static void
syslog_recv(fmd_hdl_t *hdl, fmd_event_t *ep, nvlist_t *nvl, const char *class)
{
	uint8_t version;
	boolean_t domsg;
	char *msg;

	if (nvlist_lookup_uint8(nvl, FM_VERSION, &version) != 0 ||
	    version > FM_SUSPECT_VERSION) {
		fmd_hdl_debug(hdl, "invalid event version: %u\n", version);
		syslog_stats.bad_vers.fmds_value.ui64++;
		return; /* invalid event version */
	}

	if (!syslog_msgall && nvlist_lookup_boolean_value(nvl,
	    FM_SUSPECT_MESSAGE, &domsg) == 0 && !domsg) {
		fmd_hdl_debug(hdl, "%s requested no message\n", class);
		syslog_stats.no_msg.fmds_value.ui64++;
		return; /* event is not to be messaged */
	}

	if ((msg = fmd_msg_gettext_nv(syslog_msghdl, NULL, nvl)) == NULL) {
		fmd_hdl_debug(hdl, "failed to format message");
		syslog_stats.bad_code.fmds_value.ui64++;
		return; /* libfmd_msg error */
	}

	syslog_ctl.pri &= LOG_FACMASK;
	if (strcmp(class, FM_LIST_RESOLVED_CLASS) == 0 ||
	    strcmp(class, FM_LIST_REPAIRED_CLASS) == 0)
		syslog_ctl.pri |= LOG_NOTICE;
	else
		syslog_ctl.pri |= LOG_ERR;

	syslog_emit(hdl, msg);
	free(msg);
}

static const fmd_prop_t fmd_props[] = {
	{ "console", FMD_TYPE_BOOL, "true" },
	{ "facility", FMD_TYPE_STRING, "LOG_DAEMON" },
	{ "gmt", FMD_TYPE_BOOL, "false" },
	{ "syslogd", FMD_TYPE_BOOL, "true" },
	{ "url", FMD_TYPE_STRING, "http://sun.com/msg/" },
	{ "message_all", FMD_TYPE_BOOL, "false" },
	{ NULL, 0, NULL }
};

static const fmd_hdl_ops_t fmd_ops = {
	syslog_recv,	/* fmdo_recv */
	NULL,		/* fmdo_timeout */
	NULL,		/* fmdo_close */
	NULL,		/* fmdo_stats */
	NULL,		/* fmdo_gc */
};

static const fmd_hdl_info_t fmd_info = {
	"Syslog Messaging Agent", "1.0", &fmd_ops, fmd_props
};

void
_fmd_init(fmd_hdl_t *hdl)
{
	const struct facility *fp;
	char *facname, *tz, *rootdir, *urlbase;

	if (fmd_hdl_register(hdl, FMD_API_VERSION, &fmd_info) != 0)
		return; /* invalid data in configuration file */

	(void) fmd_stat_create(hdl, FMD_STAT_NOALLOC, sizeof (syslog_stats) /
	    sizeof (fmd_stat_t), (fmd_stat_t *)&syslog_stats);

	if ((syslog_logfd = open("/dev/conslog", O_WRONLY | O_NOCTTY)) == -1)
		fmd_hdl_abort(hdl, "syslog-msgs failed to open /dev/conslog");

	if ((syslog_msgfd = open("/dev/sysmsg", O_WRONLY | O_NOCTTY)) == -1)
		fmd_hdl_abort(hdl, "syslog-msgs failed to open /dev/sysmsg");

	/*
	 * If the "gmt" property is set to true, force our EVENT-TIME to be
	 * reported in GMT time; otherwise we use localtime.  tzset() affects
	 * the results of subsequent calls to strftime(3C) above.
	 */
	if (fmd_prop_get_int32(hdl, "gmt") == FMD_B_TRUE &&
	    ((tz = getenv("TZ")) == NULL || strcmp(tz, "GMT") != 0)) {
		(void) putenv(fmd_hdl_strdup(hdl, "TZ=GMT", FMD_SLEEP));
		tzset(); /* reload env */
	}

	/*
	 * Look up the value of the "facility" property and use it to determine
	 * what syslog LOG_* facility value we use to fill in our log_ctl_t.
	 * The details of our logging method are described above syslog_emit().
	 */
	facname = fmd_prop_get_string(hdl, "facility");

	for (fp = syslog_facs; fp->fac_name != NULL; fp++) {
		if (strcmp(fp->fac_name, facname) == 0)
			break;
	}

	if (fp->fac_name == NULL)
		fmd_hdl_abort(hdl, "invalid 'facility' setting: %s\n", facname);

	fmd_prop_free_string(hdl, facname);
	syslog_ctl.pri = fp->fac_value;
	syslog_ctl.flags = SL_CONSOLE | SL_LOGONLY;

	/*
	 * Cache any properties we use every time we receive an event and
	 * subscribe to list.suspect events regardless of the .conf file.
	 */
	syslog_file = fmd_prop_get_int32(hdl, "syslogd");
	syslog_cons = fmd_prop_get_int32(hdl, "console");
	syslog_msgall = fmd_prop_get_int32(hdl, "message_all");

	rootdir = fmd_prop_get_string(hdl, "fmd.rootdir");
	syslog_msghdl = fmd_msg_init(rootdir, FMD_MSG_VERSION);
	fmd_prop_free_string(hdl, rootdir);

	if (syslog_msghdl == NULL)
		fmd_hdl_abort(hdl, "failed to initialize libfmd_msg");

	urlbase = fmd_prop_get_string(hdl, "url");
	(void) fmd_msg_url_set(syslog_msghdl, urlbase);
	fmd_prop_free_string(hdl, urlbase);

	fmd_hdl_subscribe(hdl, FM_LIST_SUSPECT_CLASS);
	fmd_hdl_subscribe(hdl, FM_LIST_REPAIRED_CLASS);
	fmd_hdl_subscribe(hdl, FM_LIST_RESOLVED_CLASS);
}

/*ARGSUSED*/
void
_fmd_fini(fmd_hdl_t *hdl)
{
	fmd_msg_fini(syslog_msghdl);
	(void) close(syslog_logfd);
	(void) close(syslog_msgfd);
}