1 files changed, 285 insertions, 0 deletions
diff --git a/lib/imsg-buffer.c b/lib/imsg-buffer.c
new file mode 100644
index 0000000..4d41702
--- /dev/null
+++ b/lib/imsg-buffer.c
@@ -0,0 +1,285 @@
+/*	$OpenBSD$	*/
+
+/*
+ * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <zebra.h>
+
+#include "queue.h"
+#include "imsg.h"
+
+static int ibuf_realloc(struct ibuf *, size_t);
+static void ibuf_enqueue(struct msgbuf *, struct ibuf *);
+static void ibuf_dequeue(struct msgbuf *, struct ibuf *);
+
+struct ibuf *ibuf_open(size_t len)
+{
+	struct ibuf *buf;
+
+	if ((buf = calloc(1, sizeof(struct ibuf))) == NULL)
+		return NULL;
+	if ((buf->buf = malloc(len)) == NULL) {
+		free(buf);
+		return NULL;
+	}
+	buf->size = buf->max = len;
+	buf->fd = -1;
+
+	return (buf);
+}
+
+struct ibuf *ibuf_dynamic(size_t len, size_t max)
+{
+	struct ibuf *buf;
+
+	if (max < len)
+		return NULL;
+
+	if ((buf = ibuf_open(len)) == NULL)
+		return NULL;
+
+	if (max > 0)
+		buf->max = max;
+
+	return (buf);
+}
+
+static int ibuf_realloc(struct ibuf *buf, size_t len)
+{
+	uint8_t *b;
+
+	/* on static buffers max is eq size and so the following fails */
+	if (buf->wpos + len > buf->max) {
+		errno = ERANGE;
+		return -1;
+	}
+
+	b = realloc(buf->buf, buf->wpos + len);
+	if (b == NULL)
+		return -1;
+	buf->buf = b;
+	buf->size = buf->wpos + len;
+
+	return 0;
+}
+
+int ibuf_add(struct ibuf *buf, const void *data, size_t len)
+{
+	if (buf->wpos + len > buf->size)
+		if (ibuf_realloc(buf, len) == -1)
+			return -1;
+
+	memcpy(buf->buf + buf->wpos, data, len);
+	buf->wpos += len;
+	return 0;
+}
+
+void *ibuf_reserve(struct ibuf *buf, size_t len)
+{
+	void *b;
+
+	if (buf->wpos + len > buf->size)
+		if (ibuf_realloc(buf, len) == -1)
+			return NULL;
+
+	b = buf->buf + buf->wpos;
+	buf->wpos += len;
+	return (b);
+}
+
+void *ibuf_seek(struct ibuf *buf, size_t pos, size_t len)
+{
+	/* only allowed to seek in already written parts */
+	if (pos + len > buf->wpos)
+		return NULL;
+
+	return (buf->buf + pos);
+}
+
+size_t ibuf_size(struct ibuf *buf)
+{
+	return (buf->wpos);
+}
+
+size_t ibuf_left(struct ibuf *buf)
+{
+	return (buf->max - buf->wpos);
+}
+
+void ibuf_close(struct msgbuf *msgbuf, struct ibuf *buf)
+{
+	ibuf_enqueue(msgbuf, buf);
+}
+
+int ibuf_write(struct msgbuf *msgbuf)
+{
+	struct iovec iov[IOV_MAX];
+	struct ibuf *buf;
+	unsigned int i = 0;
+	ssize_t n;
+
+	memset(&iov, 0, sizeof(iov));
+	TAILQ_FOREACH (buf, &msgbuf->bufs, entry) {
+		if (i >= IOV_MAX)
+			break;
+		iov[i].iov_base = buf->buf + buf->rpos;
+		iov[i].iov_len = buf->wpos - buf->rpos;
+		i++;
+	}
+
+again:
+	if ((n = writev(msgbuf->fd, iov, i)) == -1) {
+		if (errno == EINTR)
+			goto again;
+		if (errno == ENOBUFS)
+			errno = EAGAIN;
+		return -1;
+	}
+
+	if (n == 0) { /* connection closed */
+		errno = 0;
+		return 0;
+	}
+
+	msgbuf_drain(msgbuf, n);
+
+	return 1;
+}
+
+void ibuf_free(struct ibuf *buf)
+{
+	if (buf == NULL)
+		return;
+	free(buf->buf);
+	free(buf);
+}
+
+void msgbuf_init(struct msgbuf *msgbuf)
+{
+	msgbuf->queued = 0;
+	msgbuf->fd = -1;
+	TAILQ_INIT(&msgbuf->bufs);
+}
+
+void msgbuf_drain(struct msgbuf *msgbuf, size_t n)
+{
+	struct ibuf *buf, *next;
+
+	for (buf = TAILQ_FIRST(&msgbuf->bufs); buf != NULL && n > 0;
+	     buf = next) {
+		next = TAILQ_NEXT(buf, entry);
+		if (buf->rpos + n >= buf->wpos) {
+			n -= buf->wpos - buf->rpos;
+
+			TAILQ_REMOVE(&msgbuf->bufs, buf, entry);
+			ibuf_dequeue(msgbuf, buf);
+		} else {
+			buf->rpos += n;
+			n = 0;
+		}
+	}
+}
+
+void msgbuf_clear(struct msgbuf *msgbuf)
+{
+	struct ibuf *buf;
+
+	while ((buf = TAILQ_POP_FIRST(&msgbuf->bufs, entry)) != NULL)
+		ibuf_dequeue(msgbuf, buf);
+}
+
+int msgbuf_write(struct msgbuf *msgbuf)
+{
+	struct iovec iov[IOV_MAX];
+	struct ibuf *buf;
+	unsigned int i = 0;
+	ssize_t n;
+	struct msghdr msg;
+	struct cmsghdr *cmsg;
+	union {
+		struct cmsghdr hdr;
+		char buf[CMSG_SPACE(sizeof(int))];
+	} cmsgbuf;
+
+	memset(&iov, 0, sizeof(iov));
+	memset(&msg, 0, sizeof(msg));
+	memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+	TAILQ_FOREACH (buf, &msgbuf->bufs, entry) {
+		if (i >= IOV_MAX)
+			break;
+		iov[i].iov_base = buf->buf + buf->rpos;
+		iov[i].iov_len = buf->wpos - buf->rpos;
+		i++;
+		if (buf->fd != -1)
+			break;
+	}
+
+	msg.msg_iov = iov;
+	msg.msg_iovlen = i;
+
+	if (buf != NULL && buf->fd != -1) {
+		msg.msg_control = (caddr_t)&cmsgbuf.buf;
+		msg.msg_controllen = sizeof(cmsgbuf.buf);
+		cmsg = CMSG_FIRSTHDR(&msg);
+		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+		cmsg->cmsg_level = SOL_SOCKET;
+		cmsg->cmsg_type = SCM_RIGHTS;
+		memcpy(CMSG_DATA(cmsg), &buf->fd, sizeof(int));
+	}
+
+again:
+	if ((n = sendmsg(msgbuf->fd, &msg, 0)) == -1) {
+		if (errno == EINTR)
+			goto again;
+		if (errno == ENOBUFS)
+			errno = EAGAIN;
+		return -1;
+	}
+
+	if (n == 0) { /* connection closed */
+		errno = 0;
+		return 0;
+	}
+
+	/*
+	 * assumption: fd got sent if sendmsg sent anything
+	 * this works because fds are passed one at a time
+	 */
+	if (buf != NULL && buf->fd != -1) {
+		close(buf->fd);
+		buf->fd = -1;
+	}
+
+	msgbuf_drain(msgbuf, n);
+
+	return 1;
+}
+
+static void ibuf_enqueue(struct msgbuf *msgbuf, struct ibuf *buf)
+{
+	TAILQ_INSERT_TAIL(&msgbuf->bufs, buf, entry);
+	msgbuf->queued++;
+}
+
+static void ibuf_dequeue(struct msgbuf *msgbuf, struct ibuf *buf)
+{
+	/* TAILQ_REMOVE done by caller */
+	if (buf->fd != -1)
+		close(buf->fd);
+
+	msgbuf->queued--;
+	ibuf_free(buf);
+}