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-rw-r--r--monitor_fdpass.c185
1 files changed, 185 insertions, 0 deletions
diff --git a/monitor_fdpass.c b/monitor_fdpass.c
new file mode 100644
index 0000000..a07727a
--- /dev/null
+++ b/monitor_fdpass.c
@@ -0,0 +1,185 @@
+/* $OpenBSD: monitor_fdpass.c,v 1.22 2020/10/18 11:32:01 djm Exp $ */
+/*
+ * Copyright 2001 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#ifdef HAVE_SYS_UN_H
+#include <sys/un.h>
+#endif
+
+#include <errno.h>
+#include <string.h>
+#include <stdarg.h>
+
+#ifdef HAVE_POLL_H
+# include <poll.h>
+#else
+# ifdef HAVE_SYS_POLL_H
+# include <sys/poll.h>
+# endif
+#endif
+
+#include "log.h"
+#include "monitor_fdpass.h"
+
+int
+mm_send_fd(int sock, int fd)
+{
+#if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
+ struct msghdr msg;
+#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
+ union {
+ struct cmsghdr hdr;
+ char buf[CMSG_SPACE(sizeof(int))];
+ } cmsgbuf;
+ struct cmsghdr *cmsg;
+#endif
+ struct iovec vec;
+ char ch = '\0';
+ ssize_t n;
+ struct pollfd pfd;
+
+ memset(&msg, 0, sizeof(msg));
+#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
+ msg.msg_accrights = (caddr_t)&fd;
+ msg.msg_accrightslen = sizeof(fd);
+#else
+ memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+ 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;
+ *(int *)CMSG_DATA(cmsg) = fd;
+#endif
+
+ vec.iov_base = &ch;
+ vec.iov_len = 1;
+ msg.msg_iov = &vec;
+ msg.msg_iovlen = 1;
+
+ pfd.fd = sock;
+ pfd.events = POLLOUT;
+ while ((n = sendmsg(sock, &msg, 0)) == -1 &&
+ (errno == EAGAIN || errno == EINTR)) {
+ debug3_f("sendmsg(%d): %s", fd, strerror(errno));
+ (void)poll(&pfd, 1, -1);
+ }
+ if (n == -1) {
+ error_f("sendmsg(%d): %s", fd, strerror(errno));
+ return -1;
+ }
+
+ if (n != 1) {
+ error_f("sendmsg: expected sent 1 got %zd", n);
+ return -1;
+ }
+ return 0;
+#else
+ error("%s: file descriptor passing not supported", __func__);
+ return -1;
+#endif
+}
+
+int
+mm_receive_fd(int sock)
+{
+#if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
+ struct msghdr msg;
+#ifndef HAVE_ACCRIGHTS_IN_MSGHDR
+ union {
+ struct cmsghdr hdr;
+ char buf[CMSG_SPACE(sizeof(int))];
+ } cmsgbuf;
+ struct cmsghdr *cmsg;
+#endif
+ struct iovec vec;
+ ssize_t n;
+ char ch;
+ int fd;
+ struct pollfd pfd;
+
+ memset(&msg, 0, sizeof(msg));
+ vec.iov_base = &ch;
+ vec.iov_len = 1;
+ msg.msg_iov = &vec;
+ msg.msg_iovlen = 1;
+#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
+ msg.msg_accrights = (caddr_t)&fd;
+ msg.msg_accrightslen = sizeof(fd);
+#else
+ memset(&cmsgbuf, 0, sizeof(cmsgbuf));
+ msg.msg_control = &cmsgbuf.buf;
+ msg.msg_controllen = sizeof(cmsgbuf.buf);
+#endif
+
+ pfd.fd = sock;
+ pfd.events = POLLIN;
+ while ((n = recvmsg(sock, &msg, 0)) == -1 &&
+ (errno == EAGAIN || errno == EINTR)) {
+ debug3_f("recvmsg: %s", strerror(errno));
+ (void)poll(&pfd, 1, -1);
+ }
+ if (n == -1) {
+ error_f("recvmsg: %s", strerror(errno));
+ return -1;
+ }
+
+ if (n != 1) {
+ error_f("recvmsg: expected received 1 got %zd", n);
+ return -1;
+ }
+
+#ifdef HAVE_ACCRIGHTS_IN_MSGHDR
+ if (msg.msg_accrightslen != sizeof(fd)) {
+ error_f("no fd");
+ return -1;
+ }
+#else
+ cmsg = CMSG_FIRSTHDR(&msg);
+ if (cmsg == NULL) {
+ error_f("no message header");
+ return -1;
+ }
+
+#ifndef BROKEN_CMSG_TYPE
+ if (cmsg->cmsg_type != SCM_RIGHTS) {
+ error_f("expected %d got %d", SCM_RIGHTS, cmsg->cmsg_type);
+ return -1;
+ }
+#endif
+ fd = (*(int *)CMSG_DATA(cmsg));
+#endif
+ return fd;
+#else
+ error_f("file descriptor passing not supported");
+ return -1;
+#endif
+}