ldpd: use zlog recirculation for subprocesses

This way, full functionality of `zlog_*` is available.

Having `fatal()` be wrappers around `assertf()` also means we get
backtraces, which is not the case for a plain `exit(1)`.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

ldpd/lde.c

@@ -28,6 +28,7 @@
 #include "stream.h"
 #include "network.h"
 #include "libfrr.h"
+#include "zlog_live.h"
 
 static void		 lde_shutdown(void);
 static void lde_dispatch_imsg(struct event *thread);
@@ -116,6 +117,8 @@ static struct frr_signal_t lde_signals[] =
 void
 lde(void)
 {
+	static struct zlog_live_cfg child_log;
+
 #ifdef HAVE_SETPROCTITLE
 	setproctitle("label decision engine");
 #endif
@@ -123,6 +126,8 @@ lde(void)
 	log_procname = log_procnames[PROC_LDE_ENGINE];
 
 	master = frr_init();
+	zlog_live_open_fd(&child_log, LOG_DEBUG, LDPD_FD_LOG);
+
 	/* no frr_config_fork() here, allow frr_pthread to create threads */
 	frr_is_after_fork = true;
 

ldpd/ldpd.c

@@ -35,9 +35,10 @@
 #include "qobj.h"
 #include "libfrr.h"
 #include "lib_errors.h"
+#include "zlog_recirculate.h"
 
 static void		 ldpd_shutdown(void);
-static pid_t		 start_child(enum ldpd_process, char *, int, int);
+static pid_t		 start_child(enum ldpd_process, char *, int, int, int);
 static void main_dispatch_ldpe(struct event *thread);
 static void main_dispatch_lde(struct event *thread);
 static int		 main_imsg_send_ipc_sockets(struct imsgbuf *,
@@ -69,6 +70,8 @@ DEFINE_QOBJ_TYPE(l2vpn_pw);
 DEFINE_QOBJ_TYPE(l2vpn);
 DEFINE_QOBJ_TYPE(ldpd_conf);
 
+const char		*log_procname;
+
 struct ldpd_global	 global;
 struct ldpd_init	 init;
 struct ldpd_conf	*ldpd_conf, *vty_conf;
@@ -231,8 +234,12 @@ main(int argc, char *argv[])
 {
 	char			*saved_argv0;
 	int			 lflag = 0, eflag = 0;
-	int			 pipe_parent2ldpe[2], pipe_parent2ldpe_sync[2];
+	int			 pipe_parent2ldpe[2];
-	int			 pipe_parent2lde[2], pipe_parent2lde_sync[2];
+	int			 pipe_parent2ldpe_sync[2];
+	int			 pipe_ldpe_log[2];
+	int			 pipe_parent2lde[2];
+	int			 pipe_parent2lde_sync[2];
+	int			 pipe_lde_log[2];
 	bool                    ctl_sock_used = false;
 
 	ldpd_process = PROC_MAIN;
@@ -300,15 +307,6 @@ main(int argc, char *argv[])
 		exit(1);
 	}
 
-	if (lflag || eflag) {
-		struct zprivs_ids_t ids;
-
-		zprivs_preinit(&ldpd_privs);
-		zprivs_get_ids(&ids);
-
-		zlog_init(ldpd_di.progname, "LDP", 0,
-			  ids.uid_normal, ids.gid_normal);
-	}
 	if (lflag)
 		lde();
 	else if (eflag)
@@ -321,6 +319,9 @@ main(int argc, char *argv[])
 	    pipe_parent2ldpe_sync) == -1)
 		fatal("socketpair");
 
+	if (socketpair(AF_UNIX, SOCK_DGRAM, PF_UNSPEC, pipe_ldpe_log) == -1)
+		fatal("socketpair");
+
 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_parent2lde) == -1)
 		fatal("socketpair");
 
@@ -328,6 +329,9 @@ main(int argc, char *argv[])
 	    pipe_parent2lde_sync) == -1)
 		fatal("socketpair");
 
+	if (socketpair(AF_UNIX, SOCK_DGRAM, PF_UNSPEC, pipe_lde_log) == -1)
+		fatal("socketpair");
+
 	sock_set_nonblock(pipe_parent2ldpe[0]);
 	sock_set_cloexec(pipe_parent2ldpe[0]);
 	sock_set_nonblock(pipe_parent2ldpe[1]);
@@ -335,6 +339,11 @@ main(int argc, char *argv[])
 	sock_set_nonblock(pipe_parent2ldpe_sync[0]);
 	sock_set_cloexec(pipe_parent2ldpe_sync[0]);
 	sock_set_cloexec(pipe_parent2ldpe_sync[1]);
+	sock_set_nonblock(pipe_ldpe_log[0]);
+	sock_set_cloexec(pipe_ldpe_log[0]);
+	sock_set_nonblock(pipe_ldpe_log[1]);
+	sock_set_cloexec(pipe_ldpe_log[1]);
+
 	sock_set_nonblock(pipe_parent2lde[0]);
 	sock_set_cloexec(pipe_parent2lde[0]);
 	sock_set_nonblock(pipe_parent2lde[1]);
@@ -342,14 +351,24 @@ main(int argc, char *argv[])
 	sock_set_nonblock(pipe_parent2lde_sync[0]);
 	sock_set_cloexec(pipe_parent2lde_sync[0]);
 	sock_set_cloexec(pipe_parent2lde_sync[1]);
+	sock_set_nonblock(pipe_lde_log[0]);
+	sock_set_cloexec(pipe_lde_log[0]);
+	sock_set_nonblock(pipe_lde_log[1]);
+	sock_set_cloexec(pipe_lde_log[1]);
 
 	/* start children */
 	lde_pid = start_child(PROC_LDE_ENGINE, saved_argv0,
-	    pipe_parent2lde[1], pipe_parent2lde_sync[1]);
+	    pipe_parent2lde[1], pipe_parent2lde_sync[1], pipe_lde_log[1]);
 	ldpe_pid = start_child(PROC_LDP_ENGINE, saved_argv0,
-	    pipe_parent2ldpe[1], pipe_parent2ldpe_sync[1]);
+	    pipe_parent2ldpe[1], pipe_parent2ldpe_sync[1], pipe_ldpe_log[1]);
 
 	master = frr_init();
+	/* The two child processes use the zlog_live backend to send their
+	 * messages here, where the actual logging config is then applied.
+	 * Look for zlog_live_open_fd() to find the other end of this.
+	 */
+	zlog_recirculate_subscribe(master, pipe_lde_log[0]);
+	zlog_recirculate_subscribe(master, pipe_ldpe_log[0]);
 
 	vrf_init(NULL, NULL, NULL, NULL);
 	access_list_init();
@@ -484,7 +503,8 @@ ldpd_shutdown(void)
 }
 
 static pid_t
-start_child(enum ldpd_process p, char *argv0, int fd_async, int fd_sync)
+start_child(enum ldpd_process p, char *argv0, int fd_async, int fd_sync,
+	    int fd_log)
 {
 	char	*argv[7];
 	int	 argc = 0, nullfd;
@@ -499,6 +519,7 @@ start_child(enum ldpd_process p, char *argv0, int fd_async, int fd_sync)
 	default:
 		close(fd_async);
 		close(fd_sync);
+		close(fd_log);
 		return (pid);
 	}
 
@@ -520,6 +541,9 @@ start_child(enum ldpd_process p, char *argv0, int fd_async, int fd_sync)
 	if (dup2(fd_sync, LDPD_FD_SYNC) == -1)
 		fatal("cannot setup imsg sync fd");
 
+	if (dup2(fd_log, LDPD_FD_LOG) == -1)
+		fatal("cannot setup zlog fd");
+
 	argv[argc++] = argv0;
 	switch (p) {
 	case PROC_MAIN:
@@ -569,9 +593,6 @@ static void main_dispatch_ldpe(struct event *thread)
 			break;
 
 		switch (imsg.hdr.type) {
-		case IMSG_LOG:
-			logit(imsg.hdr.pid, "%s", (const char *)imsg.data);
-			break;
 		case IMSG_REQUEST_SOCKETS:
 			af = imsg.hdr.pid;
 			main_imsg_send_net_sockets(af);
@@ -637,9 +658,6 @@ static void main_dispatch_lde(struct event *thread)
 			break;
 
 		switch (imsg.hdr.type) {
-		case IMSG_LOG:
-			logit(imsg.hdr.pid, "%s", (const char *)imsg.data);
-			break;
 		case IMSG_KLABEL_CHANGE:
 			if (imsg.hdr.len - IMSG_HEADER_SIZE !=
 			    sizeof(struct kroute))

ldpd/ldpd.h

@@ -30,6 +30,7 @@
 
 #define LDPD_FD_ASYNC		3
 #define LDPD_FD_SYNC		4
+#define LDPD_FD_LOG		5
 
 #define LDPD_OPT_VERBOSE	0x00000001
 #define LDPD_OPT_VERBOSE2	0x00000002
@@ -139,7 +140,6 @@ enum imsg_type {
 	IMSG_RECONF_L2VPN_IPW,
 	IMSG_RECONF_END,
 	IMSG_DEBUG_UPDATE,
-	IMSG_LOG,
 	IMSG_ACL_CHECK,
 	IMSG_INIT,
 	IMSG_PW_UPDATE,

ldpd/ldpe.c

@@ -23,6 +23,7 @@
 #include "privs.h"
 #include "sigevent.h"
 #include "libfrr.h"
+#include "zlog_live.h"
 
 static void	 ldpe_shutdown(void);
 static void ldpe_dispatch_main(struct event *thread);
@@ -93,6 +94,8 @@ char *pkt_ptr; /* packet buffer */
 void
 ldpe(void)
 {
+	static struct zlog_live_cfg child_log;
+
 #ifdef HAVE_SETPROCTITLE
 	setproctitle("ldp engine");
 #endif
@@ -100,6 +103,8 @@ ldpe(void)
 	log_procname = log_procnames[ldpd_process];
 
 	master = frr_init();
+	zlog_live_open_fd(&child_log, LOG_DEBUG, LDPD_FD_LOG);
+
 	/* no frr_config_fork() here, allow frr_pthread to create threads */
 	frr_is_after_fork = true;
 

ldpd/log.c

@@ -1,138 +0,0 @@
-// SPDX-License-Identifier: ISC
-/*	$OpenBSD$ */
-
-/*
- * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
- */
-
-#include <zebra.h>
-
-#include "ldpd.h"
-#include "ldpe.h"
-#include "lde.h"
-#include "log.h"
-#include "printfrr.h"
-
-#include <lib/log.h>
-
-const char	*log_procname;
-
-void
-logit(int pri, const char *fmt, ...)
-{
-	va_list	ap;
-
-	va_start(ap, fmt);
-	vlog(pri, fmt, ap);
-	va_end(ap);
-}
-
-void
-vlog(int pri, const char *fmt, va_list ap)
-{
-	char	 buf[1024];
-
-	switch (ldpd_process) {
-	case PROC_LDE_ENGINE:
-		vsnprintfrr(buf, sizeof(buf), fmt, ap);
-		lde_imsg_compose_parent_sync(IMSG_LOG, pri, buf, strlen(buf) + 1);
-		break;
-	case PROC_LDP_ENGINE:
-		vsnprintfrr(buf, sizeof(buf), fmt, ap);
-		ldpe_imsg_compose_parent_sync(IMSG_LOG, pri, buf, strlen(buf) + 1);
-		break;
-	case PROC_MAIN:
-		vzlog(pri, fmt, ap);
-		break;
-	}
-}
-
-void
-log_warn(const char *emsg, ...)
-{
-	char	*nfmt;
-	va_list	 ap;
-
-	/* best effort to even work in out of memory situations */
-	if (emsg == NULL)
-		logit(LOG_ERR, "%s", strerror(errno));
-	else {
-		va_start(ap, emsg);
-
-		if (asprintf(&nfmt, "%s: %s", emsg, strerror(errno)) == -1) {
-			/* we tried it... */
-			vlog(LOG_ERR, emsg, ap);
-			logit(LOG_ERR, "%s", strerror(errno));
-		} else {
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wformat-nonliteral"
-			/* format extended above */
-			vlog(LOG_ERR, nfmt, ap);
-#pragma GCC diagnostic pop
-			free(nfmt);
-		}
-		va_end(ap);
-	}
-}
-
-void
-log_warnx(const char *emsg, ...)
-{
-	va_list	 ap;
-
-	va_start(ap, emsg);
-	vlog(LOG_ERR, emsg, ap);
-	va_end(ap);
-}
-
-void
-log_info(const char *emsg, ...)
-{
-	va_list	 ap;
-
-	va_start(ap, emsg);
-	vlog(LOG_INFO, emsg, ap);
-	va_end(ap);
-}
-
-void
-log_notice(const char *emsg, ...)
-{
-	va_list	 ap;
-
-	va_start(ap, emsg);
-	vlog(LOG_NOTICE, emsg, ap);
-	va_end(ap);
-}
-
-void
-log_debug(const char *emsg, ...)
-{
-	va_list	 ap;
-
-	va_start(ap, emsg);
-	vlog(LOG_DEBUG, emsg, ap);
-	va_end(ap);
-}
-
-void
-fatal(const char *emsg)
-{
-	if (emsg == NULL)
-		logit(LOG_CRIT, "fatal in %s: %s", log_procname, strerror(errno));
-	else
-		if (errno)
-			logit(LOG_CRIT, "fatal in %s: %s: %s",
-			    log_procname, emsg, strerror(errno));
-		else
-			logit(LOG_CRIT, "fatal in %s: %s", log_procname, emsg);
-
-	exit(1);
-}
-
-void
-fatalx(const char *emsg)
-{
-	errno = 0;
-	fatal(emsg);
-}

ldpd/log.h

@@ -8,29 +8,30 @@
 #ifndef LOG_H
 #define LOG_H
 
-#include <stdarg.h>
+#include "log.h"
+#include "assert.h"
 
 extern const char	*log_procname;
 
-void	 logit(int, const char *, ...)
+#define log_warnx	zlog_err	/* yes this is poorly named */
-		__attribute__((__format__ (printf, 2, 3)));
+#define log_warn	zlog_warn
-void	 vlog(int, const char *, va_list)
+#define log_info	zlog_info
-		__attribute__((__format__ (printf, 2, 0)));
+#define log_notice	zlog_notice	/* not used anywhere */
-void	 log_warn(const char *, ...)
+#define log_debug	zlog_debug
-		__attribute__((__format__ (printf, 1, 2)));
+
-void	 log_warnx(const char *, ...)
+#define fatal(msg)                                                             \
-		__attribute__((__format__ (printf, 1, 2)));
+	do {                                                                   \
-void	 log_info(const char *, ...)
+		assertf(0, "fatal in %s: %pSQq (%m)", log_procname,            \
-		__attribute__((__format__ (printf, 1, 2)));
+			(const char *)msg);                                    \
-void	 log_notice(const char *, ...)
+		__builtin_unreachable();                                       \
-		__attribute__((__format__ (printf, 1, 2)));
+	} while (0)                                                            \
-void	 log_debug(const char *, ...)
+	/* end */
-		__attribute__((__format__ (printf, 1, 2)));
+#define fatalx(msg)                                                            \
-void	 fatal(const char *)
+	do {                                                                   \
-		__attribute__ ((noreturn))
+		assertf(0, "fatal in %s: %pSQq", log_procname,                 \
-		__attribute__((__format__ (printf, 1, 0)));
+			(const char *)msg);                                    \
-void	 fatalx(const char *)
+		__builtin_unreachable();                                       \
-		__attribute__ ((noreturn))
+	} while (0)                                                            \
-		__attribute__((__format__ (printf, 1, 0)));
+	/* end */
 
 #endif /* LOG_H */

ldpd/subdir.am

@@ -28,7 +28,6 @@ ldpd_libldp_a_SOURCES = \
 	ldpd/ldp_vty_exec.c \
 	ldpd/ldp_zebra.c \
 	ldpd/ldpe.c \
-	ldpd/log.c \
 	ldpd/logmsg.c \
 	ldpd/neighbor.c \
 	ldpd/notification.c \