playlist_selector.c

   1 /*
   2  * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file playlist_selector.c The playlist audio file selector of paraslash  */
   8
   9 #include "server.h"
  10 #include "afs_common.h"
  11 #include "error.h"
  12 #include "net.h"
  13 #include "string.h"
  14 #include "ipc.h"
  15 #include "user_list.h"
  16 #include "playlist_selector_command_list.h"
  17
  18 /**
  19  * structure used for transmission of the playlist
  20  *
  21  * There's one such struct which gets initialized during startup. It lives in
  22  * shared memory and is used by com_lpl().
  23  */
  24 struct pls_client_data {
  25 /** allocated and set by com_lpl() (child) */
  26         int shm_id;
  27 /** the size of the shared memory area identified by \a shm_id */
  28         size_t size;
  29 /** initially locked, gets unlocked by parent when it is done */
  30         int mutex;
  31 /** return value, set by parent */
  32         int retval;
  33 };
  34
  35 /** data specific to the playlist selector */
  36 struct private_pls_data {
  37 /** guards against concurrent client access */
  38         int client_mutex;
  39 /** guards against concurrent parent-child access */
  40         int server_mutex;
  41 /** pointer to the client data */
  42         struct pls_client_data *client_data;
  43 /** id of the shm corresponding to \a client_data */
  44         int client_data_shm_id;
  45 };
  46
  47 /** we refuse to load playlists bigger than that */
  48 #define MAX_PLAYLIST_BYTES (1024 * 1024)
  49
  50 static unsigned playlist_len, playlist_size, current_playlist_entry;
  51 static char **playlist;
  52 static struct audio_file_selector *self;
  53
  54 extern struct misc_meta_data *mmd;
  55
  56 static int playlist_add(char *path, __a_unused void *data)
  57 {
  58         if (playlist_len >= playlist_size) {
  59                 playlist_size = 2 * playlist_size + 1;
  60                 playlist = para_realloc(playlist, playlist_size * sizeof(char *));
  61         }
  62         PARA_DEBUG_LOG("adding #%d/%d: %s\n", playlist_len, playlist_size, path);
  63         playlist[playlist_len++] = para_strdup(path);
  64         return 1;
  65 }
  66
  67 static int send_playlist_to_server(const char *buf, size_t size)
  68 {
  69         struct private_pls_data *ppd = self->private_data;
  70         int ret, shm_mutex = -1, shm_id = -1;
  71         void *shm = NULL;
  72
  73         PARA_DEBUG_LOG("new playlist (%zd bytes)\n", size);
  74
  75         ret = mutex_new();
  76         if (ret < 0)
  77                 return ret;
  78         shm_mutex = ret;
  79
  80         ret = shm_new(size);
  81         if (ret < 0)
  82                 goto out;
  83         shm_id = ret;
  84
  85         ret = shm_attach(shm_id, ATTACH_RW, &shm);
  86         if (ret < 0)
  87                 goto out;
  88         mutex_lock(shm_mutex);
  89         memcpy(shm, buf, size);
  90         mutex_lock(ppd->client_mutex);
  91         mutex_lock(ppd->server_mutex);
  92         ppd->client_data->size = size;
  93         ppd->client_data->shm_id = shm_id;
  94         ppd->client_data->mutex = shm_mutex;
  95         kill(getppid(), SIGUSR1); /* wake up the server */
  96         mutex_unlock(ppd->server_mutex);
  97         mutex_lock(shm_mutex); /* wait until server is done */
  98         mutex_unlock(shm_mutex);
  99         ret = ppd->client_data->retval;
 100         mutex_unlock(ppd->client_mutex);
 101         shm_detach(shm);
 102 out:
 103         if (shm_id >= 0)
 104                 shm_destroy(shm_id);
 105         mutex_destroy(shm_mutex);
 106         PARA_DEBUG_LOG("returning %d\n", ret);
 107         return ret;
 108 }
 109
 110 int com_lpl(int fd, __a_unused int argc, __a_unused char *argv[])
 111 {
 112         unsigned loaded = 0;
 113         size_t bufsize = 4096; /* guess that's enough */
 114         char *buf = para_malloc(bufsize);
 115         ssize_t ret;
 116         ret = send_buffer(fd, AWAITING_DATA_MSG);
 117         if (ret < 0)
 118                 goto out;
 119 again:
 120         ret = recv_bin_buffer(fd, buf + loaded, bufsize - loaded);
 121         if (ret < 0)
 122                 goto out;
 123         if (!ret) {
 124                 ret = send_playlist_to_server(buf, loaded);
 125                 goto out;
 126         }
 127         loaded += ret;
 128         ret = -E_LOAD_PLAYLIST;
 129         if (loaded >= MAX_PLAYLIST_BYTES)
 130                 goto out;
 131         if (loaded >= bufsize) {
 132                 bufsize *= 2;
 133                 buf = para_realloc(buf, bufsize);
 134         }
 135         goto again;
 136 out:
 137         free(buf);
 138         return ret;
 139 }
 140
 141 int com_ppl(int fd, __a_unused int argc, __a_unused char *argv[])
 142 {
 143         unsigned i;
 144
 145         PARA_DEBUG_LOG("sending playlist to client (%d entries)\n", playlist_len);
 146         for (i = 0; i < playlist_len; i++) {
 147                 int ret = send_va_buffer(fd, "%s\n", playlist[
 148                         (i + current_playlist_entry) % playlist_len]);
 149                 if (ret < 0)
 150                         return ret;
 151         }
 152         return 1;
 153 }
 154
 155 static char **pls_get_audio_file_list(unsigned int num)
 156 {
 157         char **file_list;
 158         unsigned i;
 159
 160         num = PARA_MIN(num, playlist_len);
 161         if (!num)
 162                 return NULL;
 163         file_list = para_malloc((num + 1) * sizeof(char *));
 164         for (i = 0; i < num; i++) {
 165                 unsigned j = (current_playlist_entry + i + 1) % playlist_len;
 166                 file_list[i] = para_strdup(playlist[j]);
 167         }
 168         file_list[i] = NULL;
 169         return file_list;
 170 }
 171
 172 static void free_playlist_contents(void)
 173 {
 174         int i;
 175
 176         PARA_DEBUG_LOG("freeing playlist (%d entries)\n", playlist_len);
 177         for (i = 0; i < playlist_len; i++)
 178                 free(playlist[i]);
 179         current_playlist_entry = 0;
 180         playlist_len = 0;
 181 }
 182
 183 static void pls_shutdown(void)
 184 {
 185         struct private_pls_data *ppd = self->private_data;
 186
 187         shm_detach(ppd->client_data);
 188         shm_destroy(ppd->client_data_shm_id);
 189         mutex_destroy(ppd->server_mutex);
 190         mutex_destroy(ppd->client_mutex);
 191         free(ppd);
 192         free_playlist_contents();
 193         free(playlist);
 194         playlist = NULL;
 195         playlist_len = 0;
 196         playlist_size = 0;
 197 }
 198
 199 static void pls_post_select(__a_unused fd_set *rfds, __a_unused fd_set *wfds)
 200 {
 201         struct private_pls_data *ppd = self->private_data;
 202         struct pls_client_data *pcd = ppd->client_data;
 203         int ret;
 204         void *shm;
 205
 206         mutex_lock(ppd->server_mutex);
 207         if (!pcd->size)
 208                 goto out;
 209         free_playlist_contents();
 210         ret = shm_attach(pcd->shm_id, ATTACH_RW, &shm);
 211         if (ret < 0) {
 212                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 213                 goto out;
 214         }
 215         PARA_DEBUG_LOG("loading new playlist (%zd bytes)\n", pcd->size);
 216         ret = for_each_line((char *)shm, pcd->size, &playlist_add, NULL);
 217         shm_detach(shm);
 218         PARA_NOTICE_LOG("new playlist (%d entries)\n", playlist_len);
 219         sprintf(mmd->selector_info, "dbinfo1:new playlist: %d files\n"
 220                 "dbinfo2:\ndbinfo3:\n", playlist_len);
 221         pcd->retval = 1;
 222         pcd->size = 0;
 223         mutex_unlock(pcd->mutex);
 224 out:
 225         mutex_unlock(ppd->server_mutex);
 226 }
 227
 228 static size_t string_offset(const char *str, size_t max)
 229 {
 230         size_t l = strlen(str);
 231
 232         if (l <= max)
 233                 return 0;
 234         return l - max;
 235 }
 236
 237 static void pls_update_audio_file(char *audio_file)
 238 {
 239         unsigned i;
 240         char *dir = para_dirname(audio_file),
 241                 *prev = playlist[current_playlist_entry % playlist_len];
 242         size_t dir_off = string_offset(dir, 50),
 243                 prev_off = string_offset(prev, 70);
 244
 245         for (i = 1; i <= playlist_len; i++) {
 246                 char *next;
 247                 size_t next_off;
 248                 unsigned j = (current_playlist_entry + i) % playlist_len;
 249                 if (strcmp(playlist[j], audio_file))
 250                         continue;
 251                 current_playlist_entry = j;
 252                 next = playlist[(j + 1) %playlist_len];
 253                 next_off = string_offset(next, 70);
 254                 snprintf(mmd->selector_info, MMD_INFO_SIZE,
 255                         "dbinfo1: %d files, current dir: %s%s\n"
 256                         "dbinfo2: prev: %s%s\n"
 257                         "dbinfo3: next: %s%s\n",
 258                         playlist_len,
 259                         dir_off? "... " : "", dir + dir_off,
 260                         prev_off? "... " : "", prev + prev_off,
 261                         next_off? "... " : "", next + next_off
 262                 );
 263                 break;
 264         }
 265         free(dir);
 266 }
 267
 268 /**
 269  * the init function for the playlist selector
 270  *
 271  * \param afs pointer to the struct to initialize
 272  *
 273  * Init all function pointers of \a afs
 274  *
 275  * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
 276  * random_selector.c.
 277  */
 278 int playlist_selector_init(struct audio_file_selector *afs)
 279 {
 280         int ret;
 281         struct private_pls_data *ppd = NULL;
 282         void *shm = NULL;
 283
 284         self = afs;
 285         afs->cmd_list = playlist_selector_cmds;
 286         afs->get_audio_file_list = pls_get_audio_file_list;
 287         afs->shutdown = pls_shutdown;
 288         afs->post_select = pls_post_select;
 289         afs->update_audio_file = pls_update_audio_file;
 290         ppd = para_calloc(sizeof(struct private_pls_data));
 291         afs->private_data = ppd;
 292
 293         ppd->client_mutex = -1;
 294         ppd->server_mutex = -1;
 295         ppd->client_data_shm_id = -1;
 296         ppd->client_data = NULL;
 297
 298         ret = mutex_new();
 299         if (ret < 0)
 300                 goto err_out;
 301         ppd->client_mutex = ret;
 302
 303         ret = mutex_new();
 304         if (ret < 0)
 305                 goto err_out;
 306         ppd->server_mutex = ret;
 307
 308         ret = shm_new(sizeof(struct pls_client_data));
 309         if (ret < 0)
 310                 goto err_out;
 311         ppd->client_data_shm_id = ret;
 312
 313         ret = shm_attach(ppd->client_data_shm_id, ATTACH_RW, &shm);
 314         if (ret < 0)
 315                 goto err_out;
 316         ppd->client_data = shm;
 317         ppd->client_data->size = 0;
 318         sprintf(mmd->selector_info, "dbinfo1: Welcome to the playlist "
 319                 "selector\ndbinfo2: no playlist loaded\ndbinfo3:\n");
 320         return 1;
 321 err_out:
 322         if (ppd->client_data_shm_id >= 0)
 323                 shm_destroy(ppd->client_data_shm_id);
 324         if (ppd->client_mutex >= 0)
 325                 mutex_destroy(ppd->client_mutex);
 326         if (ppd->server_mutex >= 0)
 327                 mutex_destroy(ppd->server_mutex);
 328         free(ppd);
 329         return ret;
 330 }