| 1 | /* |
| 2 | * This file is part of DisOrder. |
| 3 | * Copyright (C) 2005, 2007 Richard Kettlewell |
| 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 | */ |
| 20 | /** @file lib/speaker-protocol.c |
| 21 | * @brief Speaker/server protocol support |
| 22 | */ |
| 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 | |
| 32 | #include "speaker-protocol.h" |
| 33 | #include "log.h" |
| 34 | |
| 35 | /** @brief Send a speaker message |
| 36 | * @param fd File descriptor to send to |
| 37 | * @param sm Pointer to message |
| 38 | * @param datafd File descriptoxr to pass with message or -1 |
| 39 | * |
| 40 | * @p datafd will be the output from some decoder. |
| 41 | */ |
| 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 | |
| 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 | */ |
| 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 | */ |