460b9539 |
1 | /* |
2 | * This file is part of DisOrder. |
ea410ba1 |
3 | * Copyright (C) 2005, 2007 Richard Kettlewell |
460b9539 |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License as published by |
7 | * the Free Software Foundation; either version 2 of the License, or |
8 | * (at your option) any later version. |
9 | * |
10 | * This program is distributed in the hope that it will be useful, but |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU General Public License |
16 | * along with this program; if not, write to the Free Software |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
18 | * USA |
19 | */ |
ea410ba1 |
20 | /** @file lib/speaker-protocol.c |
21 | * @brief Speaker/server protocol support |
22 | */ |
460b9539 |
23 | |
24 | #include <config.h> |
25 | #include "types.h" |
26 | |
27 | #include <sys/socket.h> |
28 | #include <string.h> |
29 | #include <errno.h> |
30 | #include <sys/uio.h> |
31 | |
ea410ba1 |
32 | #include "speaker-protocol.h" |
460b9539 |
33 | #include "log.h" |
34 | |
fbf86993 |
35 | /** @brief Send a speaker message |
ea410ba1 |
36 | * @param fd File descriptor to send to |
37 | * @param sm Pointer to message |
fbf86993 |
38 | * @param datafd File descriptoxr to pass with message or -1 |
39 | * |
40 | * @p datafd will be the output from some decoder. |
ea410ba1 |
41 | */ |
460b9539 |
42 | void speaker_send(int fd, const struct speaker_message *sm, int datafd) { |
43 | struct msghdr m; |
44 | struct iovec iov; |
45 | union { |
46 | struct cmsghdr cmsg; |
47 | char size[CMSG_SPACE(sizeof (int))]; |
48 | } u; |
49 | int ret; |
50 | |
51 | memset(&m, 0, sizeof m); |
52 | m.msg_iov = &iov; |
53 | m.msg_iovlen = 1; |
54 | iov.iov_base = (void *)sm; |
55 | iov.iov_len = sizeof *sm; |
56 | if(datafd != -1) { |
57 | m.msg_control = (void *)&u.cmsg; |
58 | m.msg_controllen = sizeof u; |
59 | memset(&u, 0, sizeof u); |
60 | u.cmsg.cmsg_len = CMSG_LEN(sizeof (int)); |
61 | u.cmsg.cmsg_level = SOL_SOCKET; |
62 | u.cmsg.cmsg_type = SCM_RIGHTS; |
63 | *(int *)CMSG_DATA(&u.cmsg) = datafd; |
64 | } |
65 | do { |
66 | ret = sendmsg(fd, &m, 0); |
67 | } while(ret < 0 && errno == EINTR); |
68 | if(ret < 0) |
69 | fatal(errno, "sendmsg"); |
70 | } |
71 | |
ea410ba1 |
72 | /** @brief Receive a speaker message |
73 | * @param fd File descriptor to read from |
74 | * @param sm Where to store received message |
75 | * @param datafd Where to store received file descriptor or NULL |
76 | * @return -ve on @c EAGAIN, 0 at EOF, +ve on success |
77 | * |
78 | * If @p datafd is NULL but a file descriptor is nonetheless received, |
79 | * the process is terminated with an error. |
80 | */ |
460b9539 |
81 | int speaker_recv(int fd, struct speaker_message *sm, int *datafd) { |
82 | struct msghdr m; |
83 | struct iovec iov; |
84 | union { |
85 | struct cmsghdr cmsg; |
86 | char size[CMSG_SPACE(sizeof (int))]; |
87 | } u; |
88 | int ret; |
89 | |
90 | memset(&m, 0, sizeof m); |
91 | m.msg_iov = &iov; |
92 | m.msg_iovlen = 1; |
93 | iov.iov_base = (void *)sm; |
94 | iov.iov_len = sizeof *sm; |
95 | if(datafd) { |
96 | m.msg_control = (void *)&u.cmsg; |
97 | m.msg_controllen = sizeof u; |
98 | memset(&u, 0, sizeof u); |
99 | u.cmsg.cmsg_len = CMSG_LEN(sizeof (int)); |
100 | u.cmsg.cmsg_level = SOL_SOCKET; |
101 | u.cmsg.cmsg_type = SCM_RIGHTS; |
102 | *datafd = -1; |
103 | } |
104 | do { |
105 | ret = recvmsg(fd, &m, MSG_DONTWAIT); |
106 | } while(ret < 0 && errno == EINTR); |
107 | if(ret < 0) { |
108 | if(errno != EAGAIN) fatal(errno, "recvmsg"); |
109 | return -1; |
110 | } |
111 | if((size_t)m.msg_controllen >= CMSG_LEN(sizeof (int))) { |
112 | if(!datafd) |
113 | fatal(0, "got an unexpected file descriptor from recvmsg"); |
114 | else |
115 | *datafd = *(int *)CMSG_DATA(&u.cmsg); |
116 | } |
117 | return ret; |
118 | } |
119 | |
120 | /* |
121 | Local Variables: |
122 | c-basic-offset:2 |
123 | comment-column:40 |
124 | fill-column:79 |
125 | indent-tabs-mode:nil |
126 | End: |
127 | */ |