From 3896909080b4f0e0fe8fc944624ae0511d514978 Mon Sep 17 00:00:00 2001 From: Paul Lietar Date: Thu, 29 Aug 2013 18:05:09 +0200 Subject: [PATCH] Reorganize mDNS advertisement mDNS is now handled more or less in the same way audio is. Multiple mDNS backends are available, shairport tries them all until one works. This makes it, IMHO, cleaner, and easier to add other mDNS backends in the future, such as using tinysvcmdns or dns-sd library. Also it will also allow to define mDNS backends as plugins, in a similar way it is done in PR #230. --- Makefile | 4 +- avahi.h | 7 -- mdns.c | 68 +++++++++---------- mdns.h | 5 ++ avahi.c => mdns_avahi.c | 21 ++++-- mdns_external.c | 144 ++++++++++++++++++++++++++++++++++++++++ shairport.c | 3 +- 7 files changed, 198 insertions(+), 54 deletions(-) delete mode 100644 avahi.h rename avahi.c => mdns_avahi.c (92%) create mode 100644 mdns_external.c diff --git a/Makefile b/Makefile index 7a5c3051..42e44128 100644 --- a/Makefile +++ b/Makefile @@ -9,7 +9,7 @@ endif PREFIX ?= /usr/local -SRCS := shairport.c daemon.c rtsp.c mdns.c common.c rtp.c player.c alac.c audio.c audio_dummy.c audio_pipe.c +SRCS := shairport.c daemon.c rtsp.c mdns.c mdns_external.c common.c rtp.c player.c alac.c audio.c audio_dummy.c audio_pipe.c ifdef CONFIG_SNDIO SRCS += audio_sndio.c @@ -28,7 +28,7 @@ SRCS += audio_alsa.c endif ifdef CONFIG_AVAHI -SRCS += avahi.c +SRCS += mdns_avahi.c endif ifndef CONFIG_HAVE_GETOPT_H diff --git a/avahi.h b/avahi.h deleted file mode 100644 index 0ad53ff0..00000000 --- a/avahi.h +++ /dev/null @@ -1,7 +0,0 @@ -#ifndef _AVAHI_H -#define _AVAHI_H - -int avahi_register(char *srvname); -void avahi_unregister(void); - -#endif // _AVAHI_H diff --git a/mdns.c b/mdns.c index 66d88363..9720a74b 100644 --- a/mdns.c +++ b/mdns.c @@ -25,28 +25,29 @@ */ -#include #include #include -#include #include "config.h" #include "common.h" #include "mdns.h" + #ifdef CONFIG_AVAHI -#include "avahi.h" +extern mdns_backend mdns_avahi; #endif -int mdns_pid = 0; +extern mdns_backend mdns_external_avahi; +extern mdns_backend mdns_external_dns_sd; -void mdns_unregister(void) { +static mdns_backend *mdns_backends[] = { #ifdef CONFIG_AVAHI - avahi_unregister(); + &mdns_avahi, #endif + &mdns_external_avahi, + &mdns_external_dns_sd, + NULL +}; - if (mdns_pid) - kill(mdns_pid, SIGTERM); - mdns_pid = 0; -} +static mdns_backend *backend = NULL; void mdns_register(void) { char *mdns_apname = malloc(strlen(config.apname) + 14); @@ -59,31 +60,26 @@ void mdns_register(void) { *p++ = '@'; strcpy(p, config.apname); -#ifdef CONFIG_AVAHI - if (avahi_register(mdns_apname)) - return; - warn("avahi_register failed, falling back to external programs"); -#endif + backend = NULL; + mdns_backend **s = NULL; + for (s = mdns_backends; *s; s++) + { + int error = (*s)->mdns_register(mdns_apname, config.port); + if (error == 0) + { + backend = *s; + break; + } + } - if ((mdns_pid = fork())) - return; - - char mdns_port[6]; - sprintf(mdns_port, "%d", config.port); - - char *argv[] = { - NULL, mdns_apname, "_raop._tcp", mdns_port, MDNS_RECORD, NULL - }; - - argv[0] = "avahi-publish-service"; - execvp(argv[0], argv); - - argv[0] = "mDNSPublish"; - execvp(argv[0], argv); - - char *mac_argv[] = {"dns-sd", "-R", mdns_apname, "_raop._tcp", ".", - mdns_port, MDNS_RECORD, NULL}; - execvp(mac_argv[0], mac_argv); - - die("Could not establish mDNS advertisement!"); + if (backend == NULL) + die("Could not establish mDNS advertisement!"); } + +void mdns_unregister(void) { + if (backend) { + backend->mdns_unregister(); + } +} + + diff --git a/mdns.h b/mdns.h index 9fc5792f..4b5f839d 100644 --- a/mdns.h +++ b/mdns.h @@ -6,6 +6,11 @@ extern int mdns_pid; void mdns_unregister(void); void mdns_register(void); +typedef struct { + int (*mdns_register)(char *apname, int port); + void (*mdns_unregister)(void); +} mdns_backend; + #define MDNS_RECORD "tp=UDP", "sm=false", "ek=1", "et=0,1", "cn=0,1", "ch=2", \ "ss=16", "sr=44100", "vn=3", "txtvers=1", \ config.password ? "pw=true" : "pw=false" diff --git a/avahi.c b/mdns_avahi.c similarity index 92% rename from avahi.c rename to mdns_avahi.c index f38c4129..d927d51c 100644 --- a/avahi.c +++ b/mdns_avahi.c @@ -38,6 +38,7 @@ static AvahiEntryGroup *group = NULL; static AvahiThreadedPoll *tpoll = NULL; static char *name = NULL; +static int port = 0; static void egroup_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, @@ -67,7 +68,7 @@ static void register_service(AvahiClient *c) { "_raop._tcp", NULL, NULL, - config.port, + port, MDNS_RECORD, NULL); if (ret < 0) @@ -100,14 +101,15 @@ static void client_callback(AvahiClient *c, } } -int avahi_register(char *srvname) { +static int avahi_register(char *srvname, int srvport) { debug(1, "avahi: avahi_register\n"); name = strdup(srvname); + port = srvport; int err; if (!(tpoll = avahi_threaded_poll_new())) { warn("couldn't create avahi threaded tpoll!"); - return 0; + return -1; } if (!(client = avahi_client_new(avahi_threaded_poll_get(tpoll), 0, @@ -115,18 +117,18 @@ int avahi_register(char *srvname) { NULL, &err))) { warn("couldn't create avahi client: %s!", avahi_strerror(err)); - return 0; + return -1; } if (avahi_threaded_poll_start(tpoll) < 0) { warn("couldn't start avahi tpoll thread"); - return 0; + return -1; } - return 1; + return 0; } -void avahi_unregister(void) { +static void avahi_unregister(void) { debug(1, "avahi: avahi_unregister\n"); if (tpoll) avahi_threaded_poll_stop(tpoll); @@ -137,4 +139,9 @@ void avahi_unregister(void) { name = NULL; } +mdns_backend mdns_avahi = +{ + .mdns_register = avahi_register, + .mdns_unregister = avahi_unregister +}; diff --git a/mdns_external.c b/mdns_external.c new file mode 100644 index 00000000..e86d2fb7 --- /dev/null +++ b/mdns_external.c @@ -0,0 +1,144 @@ +/* + * mDNS registration handler. This file is part of Shairport. + * Copyright (c) Paul Lietar 2013 + * All rights reserved. + * + * Permission is hereby granted, free of charge, to any person + * obtaining a copy of this software and associated documentation + * files (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, + * copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT + * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, + * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +#include +#include +#include +#include +#include +#include "common.h" +#include "mdns.h" + +int mdns_pid = 0; + +/* + * Do a fork followed by a execvp, handling execvp errors correctly. + * Return the pid of the new process upon success, or -1 if something failed. + * Check errno for error details. + */ +static int fork_execvp(const char *file, char *const argv[]) { + int execpipe[2]; + int pid = 0; + if (pipe(execpipe) < 0) { + return -1; + } + + if (fcntl(execpipe[1], F_SETFD, fcntl(execpipe[1], F_GETFD) | FD_CLOEXEC) < 0) { + close(execpipe[0]); + close(execpipe[1]); + return -1; + } + + pid = fork(); + if (pid < 0) { + close(execpipe[0]); + close(execpipe[1]); + return -1; + } + else if(pid == 0) { // Child + close(execpipe[0]); // Close the read end + execvp(file, argv); + + // If we reach this point then execve has failed. + // Write erno's value into the pipe and exit. + write(execpipe[1], &errno, sizeof(errno)); + + _exit(-1); + return 0; // Just to make the compiler happy. + } + else { // Parent + close(execpipe[1]); // Close the write end + + int childErrno; + // Block until child closes the pipe or sends errno. + if(read(execpipe[0], &childErrno, sizeof(childErrno)) == sizeof(childErrno)) { // We received errno + errno = childErrno; + return -1; + } + else { // Child closed the pipe. execvp was successful. + return pid; + } + } +} + +static int mdns_external_avahi_register(char *apname, int port) { + char mdns_port[6]; + sprintf(mdns_port, "%d", config.port); + + char *argv[] = { + NULL, apname, "_raop._tcp", mdns_port, MDNS_RECORD, NULL + }; + + argv[0] = "avahi-publish-service"; + mdns_pid = fork_execvp(argv[0], argv); + if (mdns_pid > 0) + return 0; + else + warn("Calling %s failed !", argv[0]); + + argv[0] = "mDNSPublish"; + mdns_pid = fork_execvp(argv[0], argv); + if (mdns_pid > 0) + return 0; + else + warn("Calling %s failed !", argv[0]); + + // If we reach here, both execvp calls failed. + return -1; +} + +static int mdns_external_dns_sd_register(char *apname, int port) { + char mdns_port[6]; + sprintf(mdns_port, "%d", config.port); + + char *argv[] = {"dns-sd", "-R", apname, "_raop._tcp", ".", + mdns_port, MDNS_RECORD, NULL}; + + mdns_pid = fork_execvp(argv[0], argv); + if (mdns_pid > 0) + return 0; + else + warn("Calling %s failed !", argv[0]); + + return -1; +} + +static void kill_mdns_child(void) { + if (mdns_pid) + kill(mdns_pid, SIGTERM); + mdns_pid = 0; +} + +mdns_backend mdns_external_avahi = { + .mdns_register = mdns_external_avahi_register, + .mdns_unregister = kill_mdns_child +}; + +mdns_backend mdns_external_dns_sd = { + .mdns_register = mdns_external_dns_sd_register, + .mdns_unregister = kill_mdns_child +}; + diff --git a/shairport.c b/shairport.c index b30f4948..8140acd4 100644 --- a/shairport.c +++ b/shairport.c @@ -187,7 +187,7 @@ void signal_setup(void) { // setting this to SIG_IGN would prevent signalling any threads. struct sigaction sa; memset(&sa, 0, sizeof(sa)); - sa.sa_flags = SA_SIGINFO; + sa.sa_flags = SA_SIGINFO | SA_RESTART; sa.sa_sigaction = &sig_ignore; sigaction(SIGUSR1, &sa, NULL); @@ -198,7 +198,6 @@ void signal_setup(void) { sa.sa_sigaction = &sig_logrotate; sigaction(SIGHUP, &sa, NULL); - sa.sa_flags = SA_SIGINFO; sa.sa_sigaction = &sig_child; sigaction(SIGCHLD, &sa, NULL); }