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-rw-r--r--lib/imsg-buffer.c274
1 files changed, 274 insertions, 0 deletions
diff --git a/lib/imsg-buffer.c b/lib/imsg-buffer.c
new file mode 100644
index 0000000..4f041ff
--- /dev/null
+++ b/lib/imsg-buffer.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: ISC
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
+ */
+
+#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);
+}