From: Martijn van Duren <openbsd+tech@list.imperialat.at>
Subject: iked/snmpd: Implement new imsg API for proc.c
To: tech@openbsd.org
Date: Wed, 1 Jul 2026 20:20:55 +0200

Hello tech@,

Similar to a diff relayd's proc.c r1.54, and a pending diff for httpd by
rsadowski@, here's a diff to implement the new imsg API inside iked, and
snmpd, bringing the implementations a bit closer once again.

OK?

martijn@

diff d010102fe4efde3ee95164581695909c7c6b672a d99e3d210e154f2f1322afa2aa01cecfa7172ebf
commit - d010102fe4efde3ee95164581695909c7c6b672a
commit + d99e3d210e154f2f1322afa2aa01cecfa7172ebf
blob - 7bba4cba8ec28d87db99f7ca6a1b47495f86396b
blob + 35a34480c04d6125e64ec3ba2d623b392ab71146
--- sbin/iked/control.c
+++ sbin/iked/control.c
@@ -310,7 +310,7 @@ control_dispatch_imsg(int fd, short event, void *arg)
 			memcpy(&v, imsg.data, sizeof(v));
 			log_setverbose(v);
 
-			proc_forward_imsg(&env->sc_ps, &imsg, PROC_PARENT, -1);
+			proc_forward_imsg(&env->sc_ps, &imsg, PROC_PARENT);
 			break;
 		case IMSG_CTL_RELOAD:
 		case IMSG_CTL_RESET:
@@ -318,17 +318,17 @@ control_dispatch_imsg(int fd, short event, void *arg)
 		case IMSG_CTL_DECOUPLE:
 		case IMSG_CTL_ACTIVE:
 		case IMSG_CTL_PASSIVE:
-			proc_forward_imsg(&env->sc_ps, &imsg, PROC_PARENT, -1);
+			proc_forward_imsg(&env->sc_ps, &imsg, PROC_PARENT);
 			break;
 		case IMSG_CTL_RESET_ID:
-			proc_forward_imsg(&env->sc_ps, &imsg, PROC_IKEV2, -1);
+			proc_forward_imsg(&env->sc_ps, &imsg, PROC_IKEV2);
 			break;
 		case IMSG_CTL_SHOW_SA:
 		case IMSG_CTL_SHOW_STATS:
-			proc_forward_imsg(&env->sc_ps, &imsg, PROC_IKEV2, -1);
+			proc_forward_imsg(&env->sc_ps, &imsg, PROC_IKEV2);
 			break;
 		case IMSG_CTL_SHOW_CERTSTORE:
-			proc_forward_imsg(&env->sc_ps, &imsg, PROC_CERT, -1);
+			proc_forward_imsg(&env->sc_ps, &imsg, PROC_CERT);
 			break;
 		default:
 			log_debug("%s: error handling imsg %d",
blob - 8feaadef5073b9f8311e5f9226a320f3bbca624f
blob + d361d8f5abcbcdbdaa683330ef2702ab050c5be0
--- sbin/iked/iked.c
+++ sbin/iked/iked.c
@@ -434,7 +434,7 @@ parent_dispatch_ca(int fd, struct privsep_proc *p, str
 	switch (imsg->hdr.type) {
 	case IMSG_CTL_ACTIVE:
 	case IMSG_CTL_PASSIVE:
-		proc_forward_imsg(&env->sc_ps, imsg, PROC_IKEV2, -1);
+		proc_forward_imsg(&env->sc_ps, imsg, PROC_IKEV2);
 		break;
 	case IMSG_OCSP_FD:
 		ocsp_connect(env, imsg);
@@ -473,8 +473,8 @@ parent_dispatch_control(int fd, struct privsep_proc *p
 		free(str);
 		break;
 	case IMSG_CTL_VERBOSE:
-		proc_forward_imsg(&env->sc_ps, imsg, PROC_IKEV2, -1);
-		proc_forward_imsg(&env->sc_ps, imsg, PROC_CERT, -1);
+		proc_forward_imsg(&env->sc_ps, imsg, PROC_IKEV2);
+		proc_forward_imsg(&env->sc_ps, imsg, PROC_CERT);
 
 		/* return 1 to let proc.c handle it locally */
 		return (1);
blob - 367ea76047ae3d7ec009bd36cab0e3bbeb9ec36a
blob + 9d0aa6cbd06ad919737bf59c91a38dd91f956b9e
--- sbin/iked/iked.h
+++ sbin/iked/iked.h
@@ -1333,8 +1333,8 @@ int	 proc_composev_imsg(struct privsep *, enum privsep
 	    uint16_t, uint32_t, int, const struct iovec *, int);
 int	 proc_composev(struct privsep *, enum privsep_procid,
 	    uint16_t, const struct iovec *, int);
-int	 proc_forward_imsg(struct privsep *, struct imsg *,
-	    enum privsep_procid, int);
+void	 proc_forward_imsg(struct privsep *, struct imsg *,
+	    enum privsep_procid);
 struct imsgbuf *
 	 proc_ibuf(struct privsep *, enum privsep_procid, int);
 struct imsgev *
blob - 7db459f43bd5a9cdd3f1200f78543470ef2d57c7
blob + 56737effa0689ab1dd4221337bd2233974b49625
--- sbin/iked/proc.c
+++ sbin/iked/proc.c
@@ -615,7 +615,7 @@ proc_dispatch(int fd, short event, void *arg)
 	struct imsgbuf		*ibuf;
 	struct imsg		 imsg;
 	ssize_t			 n;
-	int			 verbose;
+	int			 ver;
 	const char		*title;
 	struct privsep_fd	 pf;
 
@@ -623,9 +623,11 @@ proc_dispatch(int fd, short event, void *arg)
 	ibuf = &iev->ibuf;
 
 	if (event & EV_READ) {
-		if ((n = imsgbuf_read(ibuf)) == -1)
+		switch (imsgbuf_read(ibuf)) {
+		case -1:
 			fatal("%s: imsgbuf_read", __func__);
-		if (n == 0) {
+			break;
+		case 0:
 			/* this pipe is dead, so remove the event handler */
 			event_del(&iev->ev);
 			event_loopexit(NULL);
@@ -645,15 +647,16 @@ proc_dispatch(int fd, short event, void *arg)
 	}
 
 	for (;;) {
-		if ((n = imsg_get(ibuf, &imsg)) == -1)
-			fatal("%s: imsg_get", __func__);
+		if ((n = imsgbuf_get(ibuf, &imsg)) == -1)
+			fatal("%s: imsgbuf_get", __func__);
 		if (n == 0)
 			break;
 
 #if DEBUG > 1
 		log_debug("%s: %s %d got imsg %d peerid %d from %s %d",
 		    __func__, title, ps->ps_instance + 1,
-		    imsg.hdr.type, imsg.hdr.peerid, p->p_title, imsg.hdr.pid);
+		    imsg_get_type(&imsg), imsg_get_id(&imsg),
+		    p->p_title, imsg_get_pid(&imsg));
 #endif
 
 		/*
@@ -668,11 +671,12 @@ proc_dispatch(int fd, short event, void *arg)
 		/*
 		 * Generic message handling
 		 */
-		switch (imsg.hdr.type) {
+		switch (imsg_get_type(&imsg)) {
 		case IMSG_CTL_VERBOSE:
-			IMSG_SIZE_CHECK(&imsg, &verbose);
-			memcpy(&verbose, imsg.data, sizeof(verbose));
-			log_setverbose(verbose);
+			if (imsg_get_data(&imsg, &ver, sizeof(ver)) == -1)
+			       fatalx("%s: imsg_get_data", __func__);
+
+			log_setverbose(ver);
 			break;
 		case IMSG_CTL_PROCFD:
 			if (p->p_id != PROC_PARENT) {
@@ -680,8 +684,10 @@ proc_dispatch(int fd, short event, void *arg)
 				    "IMSG_CTL_PROCFD from %s",
 				    __func__, p->p_title);
 			}
-			IMSG_SIZE_CHECK(&imsg, &pf);
-			memcpy(&pf, imsg.data, sizeof(pf));
+
+			if (imsg_get_data(&imsg, &pf, sizeof(pf)) == -1)
+				fatalx("%s: imsg_get_data", __func__);
+
 			proc_accept(ps, imsg_get_fd(&imsg), pf.pf_procid,
 			    pf.pf_instance);
 			break;
@@ -835,12 +841,18 @@ proc_composev(struct privsep *ps, enum privsep_procid 
 	return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt));
 }
 
-int
+void
 proc_forward_imsg(struct privsep *ps, struct imsg *imsg,
-    enum privsep_procid id, int n)
+    enum privsep_procid id)
 {
-	return (proc_compose_imsg(ps, id, n, imsg->hdr.type,
-	    imsg->hdr.peerid, -1, imsg->data, IMSG_DATA_SIZE(imsg)));
+	int	 m, n = -1;
+
+	proc_range(ps, id, &n, &m);
+	for (; n < m; n++) {
+		if (imsg_forward(&ps->ps_ievs[id][n].ibuf, imsg) == -1)
+			fatal("%s: imsg_forward", __func__);
+		imsg_event_add(&ps->ps_ievs[id][n]);
+	}
 }
 
 struct imsgbuf *
blob - e0ae3f6adb3a22c7b8b272311d994be93efed4fe
blob + fbe3a7c2f3487d829e32c1d539732e895bc5844b
--- usr.sbin/snmpd/proc.c
+++ usr.sbin/snmpd/proc.c
@@ -606,7 +606,7 @@ proc_dispatch(int fd, short event, void *arg)
 	struct imsgbuf		*ibuf;
 	struct imsg		 imsg;
 	ssize_t			 n;
-	int			 verbose;
+	int			 ver;
 	const char		*title;
 	struct privsep_fd	 pf;
 
@@ -614,9 +614,11 @@ proc_dispatch(int fd, short event, void *arg)
 	ibuf = &iev->ibuf;
 
 	if (event & EV_READ) {
-		if ((n = imsgbuf_read(ibuf)) == -1)
+		switch (imsgbuf_read(ibuf)) {
+		case -1:
 			fatal("%s: imsgbuf_read", __func__);
-		if (n == 0) {
+			break;
+		case 0:
 			/* this pipe is dead, so remove the event handler */
 			event_del(&iev->ev);
 			event_loopexit(NULL);
@@ -636,15 +638,16 @@ proc_dispatch(int fd, short event, void *arg)
 	}
 
 	for (;;) {
-		if ((n = imsg_get(ibuf, &imsg)) == -1)
-			fatal("%s: imsg_get", __func__);
+		if ((n = imsgbuf_get(ibuf, &imsg)) == -1)
+			fatal("%s: imsgbuf_get", __func__);
 		if (n == 0)
 			break;
 
 #if DEBUG > 1
 		log_debug("%s: %s %d got imsg %d peerid %d from %s %d",
 		    __func__, title, ps->ps_instance + 1,
-		    imsg.hdr.type, imsg.hdr.peerid, p->p_title, imsg.hdr.pid);
+		    imsg_get_type(&imsg), imsg_get_id(&imsg),
+		    p->p_title, imsg_get_pid(&imsg));
 #endif
 
 		/*
@@ -659,11 +662,12 @@ proc_dispatch(int fd, short event, void *arg)
 		/*
 		 * Generic message handling
 		 */
-		switch (imsg.hdr.type) {
+		switch (imsg_get_type(&imsg)) {
 		case IMSG_CTL_VERBOSE:
-			IMSG_SIZE_CHECK(&imsg, &verbose);
-			memcpy(&verbose, imsg.data, sizeof(verbose));
-			log_setverbose(verbose);
+			if (imsg_get_data(&imsg, &ver, sizeof(ver)) == -1)
+			       fatalx("%s: imsg_get_data", __func__);
+
+			log_setverbose(ver);
 			break;
 		case IMSG_CTL_PROCFD:
 			if (p->p_id != PROC_PARENT || ps->ps_run == NULL) {
@@ -671,8 +675,10 @@ proc_dispatch(int fd, short event, void *arg)
 				    "IMSG_CTL_PROCFD from %s",
 				    __func__, p->p_title);
 			}
-			IMSG_SIZE_CHECK(&imsg, &pf);
-			memcpy(&pf, imsg.data, sizeof(pf));
+
+			if (imsg_get_data(&imsg, &pf, sizeof(pf)) == -1)
+				fatalx("%s: imsg_get_data", __func__);
+
 			proc_accept(ps, imsg_get_fd(&imsg), pf.pf_procid,
 			    pf.pf_instance);
 			break;
@@ -829,12 +835,18 @@ proc_composev(struct privsep *ps, enum privsep_procid 
 	return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt));
 }
 
-int
+void
 proc_forward_imsg(struct privsep *ps, struct imsg *imsg,
-    enum privsep_procid id, int n)
+    enum privsep_procid id)
 {
-	return (proc_compose_imsg(ps, id, n, imsg->hdr.type,
-	    imsg->hdr.peerid, -1, imsg->data, IMSG_DATA_SIZE(imsg)));
+	int	 m, n = -1;
+
+	proc_range(ps, id, &n, &m);
+	for (; n < m; n++) {
+		if (imsg_forward(&ps->ps_ievs[id][n].ibuf, imsg) == -1)
+			fatal("%s: imsg_forward", __func__);
+		imsg_event_add(&ps->ps_ievs[id][n]);
+	}
 }
 
 struct imsgbuf *
blob - 1db290b765c0beff7e5b7680e6a13e29a648c4cd
blob + 1db6a3d3ad412fc3bca80571a6ad465430ea4cc6
--- usr.sbin/snmpd/snmpd.h
+++ usr.sbin/snmpd/snmpd.h
@@ -519,8 +519,8 @@ int	 proc_composev_imsg(struct privsep *, enum privsep
 	    u_int16_t, u_int32_t, int, const struct iovec *, int);
 int	 proc_composev(struct privsep *, enum privsep_procid,
 	    uint16_t, const struct iovec *, int);
-int	 proc_forward_imsg(struct privsep *, struct imsg *,
-	    enum privsep_procid, int);
+void	 proc_forward_imsg(struct privsep *, struct imsg *,
+	    enum privsep_procid);
 struct imsgbuf *
 	 proc_ibuf(struct privsep *, enum privsep_procid, int);
 struct imsgev *