Make struct msgbuf opaque. Introduce msgbuf_new() and msgbuf_free() for that.

This does not yet fix the imsgbuf_init() function which can now error.
OK tb@

4 files changed, 42 insertions, 21 deletions

diff --git a/lib/libutil/Symbols.map b/lib/libutil/Symbols.map
index 04ff2b37168..55d01cbba0e 100644
--- a/lib/libutil/Symbols.map
+++ b/lib/libutil/Symbols.map
@@ -93,7 +93,8 @@
 		logout;
 		logwtmp;
 		msgbuf_clear;
-		msgbuf_init;
+		msgbuf_free;
+		msgbuf_new;
 		msgbuf_queuelen;
 		msgbuf_write;
 		ober_add_bitstring;
diff --git a/lib/libutil/imsg-buffer.c b/lib/libutil/imsg-buffer.c
index b6db734d587..d0d5bbf5b6b 100644
--- a/lib/libutil/imsg-buffer.c
+++ b/lib/libutil/imsg-buffer.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: imsg-buffer.c,v 1.26 2024/11/21 13:00:14 claudio Exp $	*/
+/*	$OpenBSD: imsg-buffer.c,v 1.27 2024/11/21 13:01:07 claudio Exp $	*/
 
 /*
  * Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
@@ -32,6 +32,11 @@
 
 #include "imsg.h"
 
+struct msgbuf {
+	TAILQ_HEAD(, ibuf)	 bufs;
+	uint32_t		 queued;
+};
+
 static void	msgbuf_enqueue(struct msgbuf *, struct ibuf *);
 static void	msgbuf_dequeue(struct msgbuf *, struct ibuf *);
 static void	msgbuf_drain(struct msgbuf *, size_t);
@@ -546,11 +551,25 @@ ibuf_fd_set(struct ibuf *buf, int fd)
 		buf->fd = fd;
 }
 
-void
-msgbuf_init(struct msgbuf *msgbuf)
+struct msgbuf *
+msgbuf_new(void)
 {
+	struct msgbuf *msgbuf;
+
+	if ((msgbuf = calloc(1, sizeof(*msgbuf))) == NULL)
+		return (NULL);
 	msgbuf->queued = 0;
 	TAILQ_INIT(&msgbuf->bufs);
+
+	return msgbuf;
+}
+
+void
+msgbuf_free(struct msgbuf *msgbuf)
+{
+	if (msgbuf != NULL)
+		msgbuf_clear(msgbuf);
+	free(msgbuf);
 }
 
 uint32_t
diff --git a/lib/libutil/imsg.c b/lib/libutil/imsg.c
index a1991eecc83..4e5e9041d83 100644
--- a/lib/libutil/imsg.c
+++ b/lib/libutil/imsg.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: imsg.c,v 1.34 2024/11/21 13:00:14 claudio Exp $	*/
+/*	$OpenBSD: imsg.c,v 1.35 2024/11/21 13:01:07 claudio Exp $	*/
 
 /*
  * Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
@@ -39,7 +39,7 @@ static int	 imsg_dequeue_fd(struct imsgbuf *);
 void
 imsgbuf_init(struct imsgbuf *imsgbuf, int fd)
 {
-	msgbuf_init(&imsgbuf->w);
+	imsgbuf->w = msgbuf_new();
 	memset(&imsgbuf->r, 0, sizeof(imsgbuf->r));
 	imsgbuf->fd = fd;
 	imsgbuf->pid = getpid();
@@ -137,15 +137,16 @@ fail:
 int
 imsgbuf_write(struct imsgbuf *imsgbuf)
 {
-	return msgbuf_write(imsgbuf->fd, &imsgbuf->w);
+	return msgbuf_write(imsgbuf->fd, imsgbuf->w);
 }
 
 int
 imsgbuf_flush(struct imsgbuf *imsgbuf)
 {
-	while (imsgbuf->w.queued)
+	while (imsgbuf_queuelen(imsgbuf) > 0) {
 		if (imsgbuf_write(imsgbuf) == -1)
 			return (-1);
+	}
 	return (0);
 }
 
@@ -154,7 +155,9 @@ imsgbuf_clear(struct imsgbuf *imsgbuf)
 {
 	int	fd;
 
-	msgbuf_clear(&imsgbuf->w);
+	msgbuf_clear(imsgbuf->w);
+	msgbuf_free(imsgbuf->w);
+	imsgbuf->w = NULL;
 	while ((fd = imsg_dequeue_fd(imsgbuf)) != -1)
 		close(fd);
 }
@@ -162,7 +165,7 @@ imsgbuf_clear(struct imsgbuf *imsgbuf)
 uint32_t
 imsgbuf_queuelen(struct imsgbuf *imsgbuf)
 {
-	return msgbuf_queuelen(&imsgbuf->w);
+	return msgbuf_queuelen(imsgbuf->w);
 }
 
 ssize_t
@@ -342,8 +345,8 @@ imsg_compose_ibuf(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id,
 	if (imsg_add(hdrbuf, &hdr, sizeof(hdr)) == -1)
 		goto fail;
 
-	ibuf_close(&imsgbuf->w, hdrbuf);
-	ibuf_close(&imsgbuf->w, buf);
+	ibuf_close(imsgbuf->w, hdrbuf);
+	ibuf_close(imsgbuf->w, buf);
 	return (1);
 
  fail:
@@ -433,7 +436,7 @@ imsg_close(struct imsgbuf *imsgbuf, struct ibuf *msg)
 		hdr->flags |= IMSGF_HASFD;
 	hdr->len = ibuf_size(msg);
 
-	ibuf_close(&imsgbuf->w, msg);
+	ibuf_close(imsgbuf->w, msg);
 }
 
 void
diff --git a/lib/libutil/imsg.h b/lib/libutil/imsg.h
index e38689b7add..995c3666206 100644
--- a/lib/libutil/imsg.h
+++ b/lib/libutil/imsg.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: imsg.h,v 1.16 2024/11/21 13:00:14 claudio Exp $	*/
+/*	$OpenBSD: imsg.h,v 1.17 2024/11/21 13:01:07 claudio Exp $	*/
 
 /*
  * Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
@@ -38,22 +38,19 @@ struct ibuf {
 	int			 fd;
 };
 
-struct msgbuf {
-	TAILQ_HEAD(, ibuf)	 bufs;
-	uint32_t		 queued;
-};
-
 struct ibuf_read {
 	unsigned char		 buf[IBUF_READ_SIZE];
 	unsigned char		*rptr;
 	size_t			 wpos;
 };
 
+struct msgbuf;
 struct imsg_fd;
+
 struct imsgbuf {
 	TAILQ_HEAD(, imsg_fd)	 fds;
 	struct ibuf_read	 r;
-	struct msgbuf		 w;
+	struct msgbuf		*w;
 	int			 fd;
 	pid_t			 pid;
 };
@@ -122,7 +119,8 @@ void		 ibuf_free(struct ibuf *);
 int		 ibuf_fd_avail(struct ibuf *);
 int		 ibuf_fd_get(struct ibuf *);
 void		 ibuf_fd_set(struct ibuf *, int);
-void		 msgbuf_init(struct msgbuf *);
+struct msgbuf	*msgbuf_new(void);
+void		 msgbuf_free(struct msgbuf *);
 void		 msgbuf_clear(struct msgbuf *);
 uint32_t	 msgbuf_queuelen(struct msgbuf *);
 int		 ibuf_write(int, struct msgbuf *);