| 1 | /* |
| 2 | * This file is part of DisOrder. |
| 3 | * Copyright (C) 2004-2009, 2011 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 3 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, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU 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, see <http://www.gnu.org/licenses/>. |
| 17 | */ |
| 18 | /** @file server/background.c |
| 19 | * @brief Background process support for playing tracks |
| 20 | */ |
| 21 | |
| 22 | #include "disorder-server.h" |
| 23 | |
| 24 | /** @brief Fork the player or decoder for @p q |
| 25 | * @param ev Event loop |
| 26 | * @param player Pointer to player information |
| 27 | * @param q Track to play or decode |
| 28 | * @param child Function to run inside fork |
| 29 | * @param bgdata Passed to @c child() |
| 30 | * |
| 31 | * @c q->pl had better already be set. |
| 32 | */ |
| 33 | int play_background(ev_source *ev, |
| 34 | const struct stringlist *player, |
| 35 | struct queue_entry *q, |
| 36 | play_background_child_fn *child, |
| 37 | void *bgdata) { |
| 38 | int lfd; |
| 39 | struct pbgc_params params[1]; |
| 40 | |
| 41 | memset(params, 0, sizeof params); |
| 42 | /* Get the raw path. This needs to be done outside the fork. It's needed by |
| 43 | * the play-track callback which has to have the raw filename bytes we got |
| 44 | * from readdir() as well as the normalized unicode version of the track |
| 45 | * name. (Emphasize 'normalized'; even if you use UTF-8 for your filenames, |
| 46 | * they might not be normalized and if they are they might not be normalized |
| 47 | * to the same canonical form as DisOrder uses.) */ |
| 48 | params->rawpath = trackdb_rawpath(q->track); |
| 49 | /* Call the prefork function in the player module. None of the built-in |
| 50 | * modules use this so it's not well tested, unfortunately. */ |
| 51 | if(q->type & DISORDER_PLAYER_PREFORK) |
| 52 | if(!(q->data = play_prefork(q->pl, q->track))) { |
| 53 | disorder_error(0, "prefork function for %s failed", q->track); |
| 54 | return START_HARDFAIL; |
| 55 | } |
| 56 | /* Capture the player/decoder's stderr and feed it into our logs. |
| 57 | * |
| 58 | * Use the second arg as the tag if available (it's probably a command name), |
| 59 | * otherwise the module name. */ |
| 60 | if(!isatty(2)) |
| 61 | lfd = logfd(ev, player->s[2] ? player->s[2] : player->s[1]); |
| 62 | else |
| 63 | lfd = -1; |
| 64 | /* Parse player arguments */ |
| 65 | int optc = player->n - 2; |
| 66 | const char **optv = (const char **)&player->s[2]; |
| 67 | while(optc > 0 && optv[0][0] == '-') { |
| 68 | if(!strcmp(optv[0], "--")) { |
| 69 | ++optv; |
| 70 | --optc; |
| 71 | break; |
| 72 | } |
| 73 | /* Currently no options supported */ |
| 74 | disorder_error(0, "unknown option %s", optv[0]); |
| 75 | return START_HARDFAIL; |
| 76 | } |
| 77 | params->argc = optc; |
| 78 | params->argv = optv; |
| 79 | /* Create the child process */ |
| 80 | switch(q->pid = fork()) { |
| 81 | case 0: |
| 82 | /* Child of disorderd */ |
| 83 | exitfn = _exit; |
| 84 | progname = "disorderd-fork"; |
| 85 | ev_signal_atfork(ev); |
| 86 | signal(SIGPIPE, SIG_DFL); |
| 87 | /* Send our log output to DisOrder's logs */ |
| 88 | if(lfd != -1) { |
| 89 | xdup2(lfd, 1); |
| 90 | xdup2(lfd, 2); |
| 91 | xclose(lfd); /* tidy up */ |
| 92 | } |
| 93 | /* Create a new process group, ID = child PID */ |
| 94 | setpgid(0, 0); |
| 95 | _exit(child(q, params, bgdata)); |
| 96 | case -1: |
| 97 | /* Back in disorderd (child could not be created) */ |
| 98 | disorder_error(errno, "error calling fork"); |
| 99 | if(q->type & DISORDER_PLAYER_PREFORK) |
| 100 | play_cleanup(q->pl, q->data); /* else would leak */ |
| 101 | if(lfd != -1) |
| 102 | xclose(lfd); |
| 103 | return START_SOFTFAIL; |
| 104 | } |
| 105 | /* We don't need the child's end of the log pipe */ |
| 106 | if(lfd != -1) |
| 107 | xclose(lfd); |
| 108 | /* Set the child's process group ID. |
| 109 | * |
| 110 | * But wait, didn't we already set it in the child? Yes, but it's possible |
| 111 | * that we'll need to address it by process group ID before it gets that far, |
| 112 | * so we set it here too. One or the other may fail but as long as one |
| 113 | * succeeds that's fine. |
| 114 | */ |
| 115 | setpgid(q->pid, q->pid); |
| 116 | /* Ask the event loop to tell us when the child terminates */ |
| 117 | D(("player subprocess ID %lu", (unsigned long)q->pid)); |
| 118 | return START_OK; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | Local Variables: |
| 123 | c-basic-offset:2 |
| 124 | comment-column:40 |
| 125 | fill-column:79 |
| 126 | indent-tabs-mode:nil |
| 127 | End: |
| 128 | */ |