From: Roy Marples <roy@marples.name>
Date: Tue, 14 Jul 2026 14:35:33 +0000 (+0100)
Subject: recvmsg WAITALL
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e9496930e404eecd2e30adada9c59770d1ef9c4f;p=thirdparty%2Fdhcpcd.git

recvmsg WAITALL
---

diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index d3b2bbea..fb9a45c8 100644
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -1587,25 +1587,6 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd, int argc,
 	size_t len, l, nifaces;
 	char *tmp, *p;
 
-	/* Log the command */
-	len = 1;
-	for (opt = 0; opt < argc; opt++)
-		len += strlen(argv[opt]) + 1;
-	tmp = malloc(len);
-	if (tmp == NULL)
-		return -1;
-	p = tmp;
-	for (opt = 0; opt < argc; opt++) {
-		l = strlen(argv[opt]);
-		strlcpy(p, argv[opt], len);
-		len -= l + 1;
-		p += l;
-		*p++ = ' ';
-	}
-	*--p = '\0';
-	loginfox("control command: %s", tmp);
-	free(tmp);
-
 	/* Special commands for our control socket
 	 * as the other end should be blocking until it gets the
 	 * expected reply we should be safely able just to change the
@@ -1627,6 +1608,25 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd, int argc,
 		return 0;
 	}
 
+	/* Log the command */
+	len = 1;
+	for (opt = 0; opt < argc; opt++)
+		len += strlen(argv[opt]) + 1;
+	tmp = malloc(len);
+	if (tmp == NULL)
+		return -1;
+	p = tmp;
+	for (opt = 0; opt < argc; opt++) {
+		l = strlen(argv[opt]);
+		strlcpy(p, argv[opt], len);
+		len -= l + 1;
+		p += l;
+		*p++ = ' ';
+	}
+	*--p = '\0';
+	loginfox("control command: %s", tmp);
+	free(tmp);
+
 	optind = 0;
 	oi = 0;
 	opts = 0;
diff --git a/src/privsep-control.c b/src/privsep-control.c
index 4df347e8..d143bdbf 100644
--- a/src/privsep-control.c
+++ b/src/privsep-control.c
@@ -177,7 +177,7 @@ ps_ctl_recv(void *arg, unsigned short events)
 	if (msglen == 0)
 		goto hangup;
 	if (msglen == -1) {
-		logerr("%s: read", __func__);
+		logerr("%s: recvmsg", __func__);
 		eloop_exit(ctx->eloop, EXIT_FAILURE);
 	}
 
@@ -196,6 +196,12 @@ ps_ctl_listen(void *arg, unsigned short events)
 	struct dhcpcd_ctx *ctx = arg;
 	ssize_t len;
 	size_t msglen;
+	struct iovec iov[] = {
+		{ .iov_base = &msglen, .iov_len = sizeof(msglen), }
+	};
+	struct msghdr msg = {
+		.msg_iov = iov, .msg_iovlen = __arraycount(iov),
+	};
 	int fd;
 	struct fd_list *fdl;
 
@@ -209,11 +215,11 @@ ps_ctl_listen(void *arg, unsigned short events)
 		logerrx("%s: unexpected event 0x%04x", __func__, events);
 
 	fd = ctx->ps_control->fd;
-	len = read(fd, &msglen, sizeof(msglen));
+	len = recvmsg(fd, &msg, MSG_WAITALL);
 	if (len == 0)
 		goto hangup;
 	if (len != sizeof(msglen)) {
-		logerr("%s: read len", __func__);
+		logerr("%s: recvmsg len %zd", __func__, len);
 		goto err;
 	}
 
@@ -222,11 +228,13 @@ ps_ctl_listen(void *arg, unsigned short events)
 		goto err;
 	}
 
-	len = read(fd, ctx->ps_buf, msglen);
+	iov->iov_base = ctx->ps_buf;
+	iov->iov_len = msglen;
+	len = recvmsg(fd, &msg, MSG_WAITALL);
 	if (len == 0)
 		goto hangup;
 	if ((size_t)len != msglen) {
-		logerr("%s: read", __func__);
+		logerr("%s: recvmsg", __func__);
 		goto err;
 	}