1 files changed, 273 insertions, 0 deletions
diff --git a/lib/util/msghdr.c b/lib/util/msghdr.c
new file mode 100644
index 0000000..3a1d6f5
--- /dev/null
+++ b/lib/util/msghdr.c
@@ -0,0 +1,273 @@
+/*
+ * Unix SMB/CIFS implementation.
+ * Copyright (C) Volker Lendecke 2014
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "replace.h"
+#include "lib/util/msghdr.h"
+#include "lib/util/iov_buf.h"
+#include <sys/socket.h>
+
+#if defined(HAVE_STRUCT_MSGHDR_MSG_CONTROL)
+
+ssize_t msghdr_prep_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
+			const int *fds, size_t num_fds)
+{
+	size_t fds_size = sizeof(int) * MIN(num_fds, INT8_MAX);
+	size_t cmsg_len = CMSG_LEN(fds_size);
+	size_t cmsg_space = CMSG_SPACE(fds_size);
+	struct cmsghdr *cmsg;
+	void *fdptr;
+
+	if (num_fds == 0) {
+		if (msg != NULL) {
+			msg->msg_control = NULL;
+			msg->msg_controllen = 0;
+		}
+		/*
+		 * C99 doesn't allow 0-length arrays
+		 */
+		return 1;
+	}
+	if (num_fds > INT8_MAX) {
+		return -1;
+	}
+	if ((msg == NULL) || (cmsg_space > bufsize)) {
+		/*
+		 * C99 doesn't allow 0-length arrays
+		 */
+		return MAX(cmsg_space, 1);
+	}
+
+	msg->msg_control = buf;
+	msg->msg_controllen = cmsg_space;
+
+	cmsg = CMSG_FIRSTHDR(msg);
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	cmsg->cmsg_len = cmsg_len;
+	fdptr = CMSG_DATA(cmsg);
+	memcpy(fdptr, fds, fds_size);
+	msg->msg_controllen = cmsg->cmsg_len;
+
+	return cmsg_space;
+}
+
+size_t msghdr_prep_recv_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
+			    size_t num_fds)
+{
+	size_t ret = CMSG_SPACE(sizeof(int) * num_fds);
+
+	if (bufsize < ret) {
+		return ret;
+	}
+	if (msg != NULL) {
+		if (num_fds != 0) {
+			msg->msg_control = buf;
+			msg->msg_controllen = ret;
+		} else {
+			msg->msg_control = NULL;
+			msg->msg_controllen = 0;
+		}
+	}
+	return ret;
+}
+
+size_t msghdr_extract_fds(struct msghdr *msg, int *fds, size_t fds_size)
+{
+	struct cmsghdr *cmsg;
+	size_t num_fds;
+
+	for(cmsg = CMSG_FIRSTHDR(msg);
+	    cmsg != NULL;
+	    cmsg = CMSG_NXTHDR(msg, cmsg))
+	{
+		if ((cmsg->cmsg_type == SCM_RIGHTS) &&
+		    (cmsg->cmsg_level == SOL_SOCKET)) {
+			break;
+		}
+	}
+
+	if (cmsg == NULL) {
+		return 0;
+	}
+
+	num_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+
+	if ((num_fds != 0) && (fds != NULL) && (fds_size >= num_fds)) {
+		memcpy(fds, CMSG_DATA(cmsg), num_fds * sizeof(int));
+	}
+
+	return num_fds;
+}
+
+#elif defined(HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS)
+
+ssize_t msghdr_prep_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
+			const int *fds, size_t num_fds)
+{
+	size_t needed;
+
+	if (num_fds > INT8_MAX) {
+		return -1;
+	}
+
+	needed = sizeof(int) * num_fds;
+
+	if ((msg == NULL) || (needed > bufsize)) {
+		return needed;
+	}
+
+	memcpy(buf, fds, needed);
+
+	msg->msg_accrights = (caddr_t) buf;
+	msg->msg_accrightslen = needed;
+
+	return needed;
+}
+
+size_t msghdr_prep_recv_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
+			    size_t num_fds)
+{
+	size_t ret = num_fds * sizeof(int);
+
+	if (bufsize < ret) {
+		return ret;
+	}
+
+	if (msg != NULL) {
+		if (num_fds != 0) {
+			msg->msg_accrights = (caddr_t) buf;
+			msg->msg_accrightslen = ret;
+		} else {
+			msg->msg_accrights = NULL;
+			msg->msg_accrightslen = 0;
+		}
+	}
+	return ret;
+}
+
+size_t msghdr_extract_fds(struct msghdr *msg, int *fds, size_t fds_size)
+{
+	size_t num_fds = msg->msg_accrightslen / sizeof(int);
+
+	if ((fds != 0) && (num_fds <= fds_size)) {
+		memcpy(fds, msg->msg_accrights, msg->msg_accrightslen);
+	}
+
+	return num_fds;
+}
+
+#else
+
+ssize_t msghdr_prep_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
+			const int *fds, size_t num_fds)
+{
+	return -1;
+}
+
+size_t msghdr_prep_recv_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
+			    size_t num_fds)
+{
+	return 0;
+}
+
+size_t msghdr_extract_fds(struct msghdr *msg, int *fds, size_t fds_size)
+{
+	return 0;
+}
+
+#endif
+
+struct msghdr_buf {
+	struct msghdr msg;
+	struct sockaddr_storage addr;
+	struct iovec iov;
+	uint8_t buf[];
+};
+
+ssize_t msghdr_copy(struct msghdr_buf *msg, size_t msgsize,
+		    const void *addr, socklen_t addrlen,
+		    const struct iovec *iov, int iovcnt,
+		    const int *fds, size_t num_fds)
+{
+	ssize_t fd_len;
+	size_t iov_len, needed, bufsize;
+
+	bufsize = (msgsize > offsetof(struct msghdr_buf, buf)) ?
+		msgsize - offsetof(struct msghdr_buf, buf) : 0;
+
+	if (msg != NULL) {
+		msg->msg = (struct msghdr) { 0 };
+
+		fd_len = msghdr_prep_fds(&msg->msg, msg->buf, bufsize,
+					 fds, num_fds);
+	} else {
+		fd_len = msghdr_prep_fds(NULL, NULL, bufsize, fds, num_fds);
+	}
+
+	if (fd_len == -1) {
+		return -1;
+	}
+
+	if (bufsize >= (size_t)fd_len) {
+		bufsize -= fd_len;
+	} else {
+		bufsize = 0;
+	}
+
+	if (msg != NULL) {
+
+		if (addr != NULL) {
+			if (addrlen > sizeof(struct sockaddr_storage)) {
+				errno = EMSGSIZE;
+				return -1;
+			}
+			memcpy(&msg->addr, addr, addrlen);
+			msg->msg.msg_name = &msg->addr;
+			msg->msg.msg_namelen = addrlen;
+		} else {
+			msg->msg.msg_name = NULL;
+			msg->msg.msg_namelen = 0;
+		}
+
+		msg->iov.iov_base = msg->buf + fd_len;
+		msg->iov.iov_len = iov_buf(
+			iov, iovcnt, msg->iov.iov_base, bufsize);
+		iov_len = msg->iov.iov_len;
+
+		msg->msg.msg_iov = &msg->iov;
+		msg->msg.msg_iovlen = 1;
+	} else {
+		iov_len = iov_buflen(iov, iovcnt);
+	}
+
+	needed = offsetof(struct msghdr_buf, buf) + fd_len;
+	if (needed < (size_t)fd_len) {
+		return -1;
+	}
+	needed += iov_len;
+	if (needed < iov_len) {
+		return -1;
+	}
+
+	return needed;
+}
+
+struct msghdr *msghdr_buf_msghdr(struct msghdr_buf *msg)
+{
+	return &msg->msg;
+}