1 /* Copyright (C) 2011-2014 Free Software Foundation, Inc.
3 This program is free software: you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; either version 3 of the License, or
6 (at your option) any later version.
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
13 You should have received a copy of the GNU General Public License
14 along with this program. If not, see <http://www.gnu.org/licenses/>. */
26 #include <sys/types.h>
29 #include <sys/socket.h>
33 /* The code that uses CMSG_FIRSTHDR is enabled on
34 Linux, Mac OS X, FreeBSD, OpenBSD, NetBSD, AIX, OSF/1, Cygwin.
35 The code that uses HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS is enabled on
36 HP-UX, IRIX, Solaris. */
38 /* MSG_CMSG_CLOEXEC is defined only on Linux, as of 2011. */
39 #ifndef MSG_CMSG_CLOEXEC
40 # define MSG_CMSG_CLOEXEC 0
44 /* sendfd sends the file descriptor fd along the socket
45 to a process calling recvfd on the other end.
47 Return 0 on success, or -1 with errno set in case of error.
50 sendfd (int sock, int fd)
57 char buf[CMSG_SPACE (sizeof fd)];
60 /* send at least one char */
61 memset (&msg, 0, sizeof msg);
70 msg.msg_control = buf;
71 msg.msg_controllen = sizeof buf;
72 cmsg = CMSG_FIRSTHDR (&msg);
73 cmsg->cmsg_level = SOL_SOCKET;
74 cmsg->cmsg_type = SCM_RIGHTS;
75 cmsg->cmsg_len = CMSG_LEN (sizeof fd);
76 /* Initialize the payload: */
77 memcpy (CMSG_DATA (cmsg), &fd, sizeof fd);
78 # elif HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
79 msg.msg_accrights = &fd;
80 msg.msg_accrightslen = sizeof fd;
86 if (sendmsg (sock, &msg, 0) != iov.iov_len)
92 sendfd (int sock _GL_UNUSED, int fd _GL_UNUSED)
101 /* recvfd receives a file descriptor through the socket.
102 The flags are a bitmask, possibly including O_CLOEXEC (defined in <fcntl.h>).
104 Return the fd on success, or -1 with errno set in case of error.
107 recvfd (int sock, int flags)
114 # ifdef CMSG_FIRSTHDR
115 struct cmsghdr *cmsg;
116 char buf[CMSG_SPACE (sizeof fd)];
117 int flags_recvmsg = flags & O_CLOEXEC ? MSG_CMSG_CLOEXEC : 0;
120 if ((flags & ~O_CLOEXEC) != 0)
126 /* send at least one char */
127 memset (&msg, 0, sizeof msg);
128 iov.iov_base = &byte;
135 # ifdef CMSG_FIRSTHDR
136 msg.msg_control = buf;
137 msg.msg_controllen = sizeof buf;
138 cmsg = CMSG_FIRSTHDR (&msg);
139 cmsg->cmsg_level = SOL_SOCKET;
140 cmsg->cmsg_type = SCM_RIGHTS;
141 cmsg->cmsg_len = CMSG_LEN (sizeof fd);
142 /* Initialize the payload: */
143 memcpy (CMSG_DATA (cmsg), &fd, sizeof fd);
144 msg.msg_controllen = cmsg->cmsg_len;
146 len = recvmsg (sock, &msg, flags_recvmsg);
150 cmsg = CMSG_FIRSTHDR (&msg);
152 if (len == 0 || cmsg == NULL || cmsg->cmsg_len != CMSG_LEN (sizeof fd)
153 || cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
155 /* fake errno: at end the file is not available */
156 errno = len ? EACCES : ENOTCONN;
160 memcpy (&fd, CMSG_DATA (cmsg), sizeof fd);
162 /* set close-on-exec flag */
163 if (!MSG_CMSG_CLOEXEC && (flags & O_CLOEXEC))
165 if (set_cloexec_flag (fd, true) < 0)
167 int saved_errno = errno;
174 # elif HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
175 msg.msg_accrights = &fd;
176 msg.msg_accrightslen = sizeof fd;
177 if (recvmsg (sock, &msg, 0) < 0)
180 /* set close-on-exec flag */
181 if (flags & O_CLOEXEC)
183 if (set_cloexec_flag (fd, true) < 0)
185 int saved_errno = errno;
199 recvfd (int sock _GL_UNUSED, int flags _GL_UNUSED)