playlist_selector.c

   1 /*
   2  * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file playlist_selector.c The playlist audio file selector of paraslash  */
  20
  21 #include "server.h"
  22 #include "db.h"
  23 #include "error.h"
  24 #include "net.h"
  25 #include "string.h"
  26 #include "ipc.h"
  27
  28 /**
  29  * structure used for transmission of the playlist
  30  *
  31  * There's one such struct which gets initialized during startup. It lives in
  32  * shared memory and is used by com_lpl().
  33  */
  34 struct pls_client_data {
  35 /** allocated and set by com_lpl() (child) */
  36         int shm_id;
  37 /** the size of the shared memory area identified by \a shm_id */
  38         size_t size;
  39 /** initially locked, gets unlocked by parent when it is done */
  40         int mutex;
  41 /** return value, set by parent */
  42         int retval;
  43 };
  44
  45 /** data specific to the playlist selector */
  46 struct private_pls_data {
  47 /** guards against concurrent client access */
  48         int client_mutex;
  49 /** guards against concurrent parent-child access */
  50         int server_mutex;
  51 /** pointer to the client data */
  52         struct pls_client_data *client_data;
  53 /** id of the shm corresponding to \a client_data */
  54         int client_data_shm_id;
  55 };
  56
  57 /** we refuse to load playlists bigger than that */
  58 #define MAX_PLAYLIST_BYTES (1024 * 1024)
  59
  60 static unsigned playlist_len, playlist_size, current_playlist_entry;
  61 static char **playlist;
  62 static struct audio_file_selector *self;
  63
  64 static int com_ppl(int, int, char **);
  65 static int com_lpl(int, int, char **);
  66 extern struct misc_meta_data *mmd;
  67
  68 /* array of supported commands */
  69 static struct server_command cmds[] = {
  70 {
  71 .name = "ppl",
  72 .handler = com_ppl,
  73 .perms = DB_READ,
  74 .description = "print playlist",
  75 .synopsis = "ppl",
  76 .help =
  77 "Print out the current playlist"
  78 }, {
  79 .name = "lpl",
  80 .handler = com_lpl,
  81 .perms = DB_WRITE,
  82 .description = "load playlist",
  83 .synopsis = "lpl",
  84 .help =
  85 "Read a new playlist from stdin. Example:\n"
  86 "\tfind /audio -name '*.mp3' | para_client lpl"
  87 }, {
  88 .name = NULL,
  89 }
  90 };
  91
  92 static void playlist_add(char *path)
  93 {
  94         if (playlist_len >= playlist_size) {
  95                 playlist_size = 2 * playlist_size + 1;
  96                 playlist = para_realloc(playlist, playlist_size * sizeof(char *));
  97         }
  98         PARA_DEBUG_LOG("adding #%d/%d: %s\n", playlist_len, playlist_size, path);
  99         playlist[playlist_len++] = para_strdup(path);
 100 }
 101
 102 static int send_playlist_to_server(const char *buf, size_t size)
 103 {
 104         struct private_pls_data *ppd = self->private_data;
 105         int ret, shm_mutex = -1, shm_id = -1;
 106         void *shm = NULL;
 107
 108         PARA_DEBUG_LOG("new playlist (%d bytes)\n", size);
 109
 110         ret = mutex_new();
 111         if (ret < 0)
 112                 return ret;
 113         shm_mutex = ret;
 114
 115         ret = shm_new(size);
 116         if (ret < 0)
 117                 goto out;
 118         shm_id = ret;
 119
 120         ret = shm_attach(shm_id, ATTACH_RW, &shm);
 121         if (ret < 0)
 122                 goto out;
 123         mutex_lock(shm_mutex);
 124         memcpy(shm, buf, size);
 125         mutex_lock(ppd->client_mutex);
 126         mutex_lock(ppd->server_mutex);
 127         ppd->client_data->size = size;
 128         ppd->client_data->shm_id = shm_id;
 129         ppd->client_data->mutex = shm_mutex;
 130         kill(getppid(), SIGUSR1); /* wake up the server */
 131         mutex_unlock(ppd->server_mutex);
 132         mutex_lock(shm_mutex); /* wait until server is done */
 133         mutex_unlock(shm_mutex);
 134         ret = ppd->client_data->retval;
 135         mutex_unlock(ppd->client_mutex);
 136         shm_detach(shm);
 137 out:
 138         if (shm_id >= 0)
 139                 shm_destroy(shm_id);
 140         mutex_destroy(shm_mutex);
 141         PARA_DEBUG_LOG("returning %d\n", ret);
 142         return ret;
 143 }
 144
 145 static int com_lpl(int fd, __unused int argc, __unused char *argv[])
 146 {
 147         unsigned loaded = 0;
 148         size_t bufsize = 4096; /* guess that's enough */
 149         char *buf = para_malloc(bufsize);
 150         ssize_t ret;
 151         ret = send_buffer(fd, AWAITING_DATA_MSG);
 152         if (ret < 0)
 153                 goto out;
 154 again:
 155         ret = recv_bin_buffer(fd, buf + loaded, bufsize - loaded);
 156         if (ret < 0)
 157                 goto out;
 158         if (!ret) {
 159                 ret = send_playlist_to_server(buf, loaded);
 160                 goto out;
 161         }
 162         loaded += ret;
 163         ret = -E_LOAD_PLAYLIST;
 164         if (loaded >= MAX_PLAYLIST_BYTES)
 165                 goto out;
 166         if (loaded >= bufsize) {
 167                 bufsize *= 2;
 168                 buf = para_realloc(buf, bufsize);
 169         }
 170         goto again;
 171 out:
 172         free(buf);
 173         return ret;
 174 }
 175
 176 static int com_ppl(int fd, __unused int argc, __unused char *argv[])
 177 {
 178         unsigned i;
 179
 180         PARA_DEBUG_LOG("sending playlist to client (%d entries)\n", playlist_len);
 181         for (i = 0; i < playlist_len; i++) {
 182                 int ret = send_va_buffer(fd, "%s\n", playlist[
 183                         (i + current_playlist_entry) % playlist_len]);
 184                 if (ret < 0)
 185                         return ret;
 186         }
 187         return 1;
 188 }
 189
 190 static char **pls_get_audio_file_list(unsigned int num)
 191 {
 192         char **file_list;
 193         unsigned i;
 194
 195         num = MIN(num, playlist_len);
 196         if (!num)
 197                 return NULL;
 198         file_list = para_malloc((num + 1) * sizeof(char *));
 199         for (i = 0; i < num; i++) {
 200                 unsigned j = (current_playlist_entry + i) % playlist_len;
 201                 file_list[i] = para_strdup(playlist[j]);
 202         }
 203         file_list[i] = NULL;
 204         return file_list;
 205 }
 206
 207 static void free_playlist_contents(void)
 208 {
 209         int i;
 210
 211         PARA_DEBUG_LOG("freeing playlist (%d entries)\n", playlist_len);
 212         for (i = 0; i < playlist_len; i++)
 213                 free(playlist[i]);
 214         current_playlist_entry = 0;
 215         playlist_len = 0;
 216 }
 217
 218 static void pls_shutdown(void)
 219 {
 220         struct private_pls_data *ppd = self->private_data;
 221
 222         shm_detach(ppd->client_data);
 223         shm_destroy(ppd->client_data_shm_id);
 224         mutex_destroy(ppd->server_mutex);
 225         mutex_destroy(ppd->client_mutex);
 226         free(ppd);
 227         free_playlist_contents();
 228         free(playlist);
 229         playlist = NULL;
 230         playlist_len = 0;
 231         playlist_size = 0;
 232 }
 233
 234 static void pls_post_select(__unused fd_set *rfds, __unused fd_set *wfds)
 235 {
 236         struct private_pls_data *ppd = self->private_data;
 237         struct pls_client_data *pcd = ppd->client_data;
 238         int ret;
 239         void *shm;
 240
 241         mutex_lock(ppd->server_mutex);
 242         if (!pcd->size)
 243                 goto out;
 244         free_playlist_contents();
 245         ret = shm_attach(pcd->shm_id, ATTACH_RW, &shm);
 246         if (ret < 0) {
 247                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 248                 goto out;
 249         }
 250         PARA_DEBUG_LOG("loading new playlist (%d bytes)\n", pcd->size);
 251         ret = for_each_line((char *)shm, pcd->size, &playlist_add);
 252         shm_detach(shm);
 253         PARA_NOTICE_LOG("new playlist (%d entries)\n", playlist_len);
 254         pcd->retval = 1;
 255         pcd->size = 0;
 256         mutex_unlock(pcd->mutex);
 257 out:
 258         mutex_unlock(ppd->server_mutex);
 259 }
 260
 261 void pls_update_audio_file(char *audio_file)
 262 {
 263         unsigned i;
 264
 265         for (i = 0; i < playlist_len; i++) {
 266                 unsigned j = (current_playlist_entry + i) % playlist_len;
 267                 if (strcmp(playlist[j], audio_file))
 268                         continue;
 269                 current_playlist_entry = (j + 1) % playlist_len;
 270         }
 271 }
 272
 273 /**
 274  * the init function for the playlist selector
 275  *
 276  * Init all function pointers of \a db
 277  *
 278  * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
 279  * random_selector.c.
 280  */
 281 int playlist_selector_init(struct audio_file_selector *db)
 282 {
 283         int ret;
 284         struct private_pls_data *ppd = NULL;
 285         void *shm = NULL;
 286
 287         self = db;
 288         db->cmd_list = cmds;
 289         db->get_audio_file_list = pls_get_audio_file_list;
 290         db->shutdown = pls_shutdown;
 291         db->post_select = pls_post_select;
 292         db->update_audio_file = pls_update_audio_file;
 293         ppd = para_calloc(sizeof(struct private_pls_data));
 294         db->private_data = ppd;
 295
 296         ppd->client_mutex = -1;
 297         ppd->server_mutex = -1;
 298         ppd->client_data_shm_id = -1;
 299         ppd->client_data = NULL;
 300
 301         ret = mutex_new();
 302         if (ret < 0)
 303                 goto err_out;
 304         ppd->client_mutex = ret;
 305
 306         ret = mutex_new();
 307         if (ret < 0)
 308                 goto err_out;
 309         ppd->server_mutex = ret;
 310
 311         ret = shm_new(sizeof(struct pls_client_data));
 312         if (ret < 0)
 313                 goto err_out;
 314         ppd->client_data_shm_id = ret;
 315
 316         ret = shm_attach(ppd->client_data_shm_id, ATTACH_RW, &shm);
 317         if (ret < 0)
 318                 goto err_out;
 319         ppd->client_data = shm;
 320         ppd->client_data->size = 0;
 321         sprintf(mmd->selector_info, "playlist selector initialized");
 322         return 1;
 323 err_out:
 324         if (ppd->client_data_shm_id >= 0)
 325                 shm_destroy(ppd->client_data_shm_id);
 326         if (ppd->client_mutex >= 0)
 327                 mutex_destroy(ppd->client_mutex);
 328         if (ppd->server_mutex >= 0)
 329                 mutex_destroy(ppd->server_mutex);
 330         free(ppd);
 331         return ret;
 332 }