stat.c

   1 /*
   2  * Copyright (C) 2005-2006 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 /**
  20  *  \file stat.c functions used for sending/receiving the status of para_server
  21  *  and para_audiod
  22  */
  23 #include "para.h"
  24 #include "close_on_fork.h"
  25 #include "list.h"
  26 #include "error.h"
  27 #include "string.h"
  28
  29 /** the maximal number of simultaneous connections */
  30 #define MAX_STAT_CLIENTS 50
  31
  32 /**
  33  * The structure associated with a connected client that sent the 'stat' command
  34 *
  35  *
  36  * A status client is identified by its file descriptor.  para_audiod
  37  * keeps a list of connected status clients.
  38  */
  39 struct stat_client {
  40 /**
  41  *
  42  *
  43  * the stat client's file descriptor
  44  */
  45 int fd;
  46 /**
  47  *
  48  * its entry in the list of stat clients
  49 */
  50 struct list_head node;
  51 };
  52
  53 static struct list_head client_list;
  54 static int initialized;
  55 static int num_clients;
  56
  57 /**
  58  * the list of all status items sent by para_server/para_audiod
  59  */
  60 const char *status_item_list[NUM_STAT_ITEMS] = {
  61         [SI_STATUS_BAR] = "status_bar",
  62         [SI_STATUS] = "status",
  63         [SI_NUM_PLAYED] = "num_played",
  64
  65         [SI_MTIME] = "mtime",
  66         [SI_LENGTH_MIN] = "length_min",
  67         [SI_LENGTH_SEC] = "length_sec",
  68
  69         [SI_FILE_SIZE] = "file_size",
  70         [SI_STATUS_FLAGS] = "status_flags",
  71         [SI_FORMAT] = "format",
  72
  73         [SI_SCORE] = "score",
  74         [SI_AUDIO_INFO1] = "audio_file_info1",
  75         [SI_AUDIO_INFO2] = "audio_file_info2",
  76
  77         [SI_AUDIO_INFO3] = "audio_file_info3",
  78         [SI_DBINFO1] = "dbinfo1",
  79         [SI_DBINFO2] = "dbinfo2",
  80
  81         [SI_DBINFO3] = "dbinfo3",
  82         [SI_DECODER_FLAGS] = "decoder_flags",
  83         [SI_AUDIOD_STATUS] = "audiod_status",
  84
  85         [SI_PLAY_TIME] = "play_time",
  86         [SI_UPTIME] = "uptime",
  87         [SI_OFFSET] = "offset",
  88
  89         [SI_LENGTH] = "length",
  90         [SI_STREAM_START] = "stream_start",
  91         [SI_CURRENT_TIME] = "current_time",
  92
  93         [SI_AUDIOD_UPTIME] = "audiod_uptime",
  94         [SI_DBTOOL] = "dbtool"
  95 };
  96 #define FOR_EACH_STAT_ITEM(i) for (i = 0; i < NUM_STAT_ITEMS; i++)
  97
  98 static void dump_stat_client_list(void)
  99 {
 100         struct stat_client *sc;
 101
 102         if (!initialized)
 103                 return;
 104         list_for_each_entry(sc, &client_list, node)
 105                 PARA_INFO_LOG("stat client on fd %d\n", sc->fd);
 106 }
 107 /**
 108  * add a status client to the list
 109  *
 110  * \return Positive value on success, or -E_TOO_MANY_CLIENTS if
 111  * the number of connected clients exceeds #MAX_STAT_CLIENTS
 112  */
 113 int stat_client_add(int fd)
 114 {
 115         struct stat_client *new_client;
 116
 117         if (num_clients >= MAX_STAT_CLIENTS) {
 118                 PARA_ERROR_LOG("maximal number of stat clients (%d) exceeded\n",
 119                         MAX_STAT_CLIENTS);
 120                 return -E_TOO_MANY_CLIENTS;
 121         }
 122         if (!initialized) {
 123                 INIT_LIST_HEAD(&client_list);
 124                 initialized = 1;
 125         }
 126         PARA_INFO_LOG("adding client on fd %d\n", fd);
 127         new_client = para_malloc(sizeof(struct stat_client));
 128         new_client->fd = fd;
 129         add_close_on_fork_list(fd);
 130         list_add(&new_client->node, &client_list);
 131         dump_stat_client_list();
 132         num_clients++;
 133         return 1;
 134 }
 135 /**
 136  * write a message to all connected stat clients
 137  *
 138  * \param msg a \p NULL terminated buffer
 139  */
 140 void stat_client_write(char *msg)
 141 {
 142         struct stat_client *sc, *tmp;
 143         char *buf;
 144         ssize_t len;
 145         struct timeval tv = {0 , 0};
 146
 147         if (!initialized)
 148                 return;
 149         buf = make_message("%s\n", msg);
 150         len = strlen(buf);
 151         list_for_each_entry_safe(sc, tmp, &client_list, node) {
 152                 int fd = sc->fd, ret;
 153                 fd_set wfds;
 154                 FD_ZERO(&wfds);
 155                 FD_SET(fd, &wfds);
 156 //              PARA_DEBUG_LOG("%s: p=%lx\n", __func__, (long)p);
 157                 do
 158                         ret = select(fd + 1, NULL, &wfds, NULL, &tv);
 159                 while (ret < 0 && errno == EINTR);
 160                 if (ret) {
 161                         ret = write(fd, buf, len);
 162                         PARA_DEBUG_LOG("dumped %s to fd %d, ret = %d\n", msg, fd, ret);
 163                         if (ret == len )
 164                                 continue;
 165                 }
 166                 /* write error or fd not ready for writing */
 167                 close(fd);
 168                 del_close_on_fork_list(fd);
 169                 num_clients--;
 170                 PARA_INFO_LOG("deleting client on fd %d\n", fd);
 171                 list_del(&sc->node);
 172                 free(sc);
 173                 dump_stat_client_list();
 174         }
 175         free(buf);
 176         PARA_DEBUG_LOG("%d client(s)\n", num_clients);
 177 }
 178
 179 /**
 180  * send empty status list
 181  *
 182  * Send to  each connected client the full status item list
 183  * with empty values.
 184  */
 185 void dump_empty_status(void)
 186 {
 187         int i;
 188         char *empty_items = NULL;
 189
 190         if (!initialized)
 191                 return;
 192         FOR_EACH_STAT_ITEM(i) {
 193                 char *tmp = make_message("%s%s:\n", empty_items? empty_items : "",
 194                         status_item_list[i]);
 195                 free(empty_items);
 196                 empty_items = tmp;
 197         }
 198 //      PARA_DEBUG_LOG("%s: empty items: %s\n", __func__, empty_items);
 199         stat_client_write(empty_items);
 200         free(empty_items);
 201 }
 202
 203 /**
 204  * check if line starts with known status item.
 205  *
 206  * \param line buffer containing the line
 207  *
 208  * \return If the beginning of \a line matches any paraslash status item and is
 209  * followed by a colon, the number of that status item is returned. Otherwise,
 210  * this function returns \p -E_UNKNOWN_STAT_ITEM.
 211  */
 212 int stat_line_valid(const char *line)
 213 {
 214         int i;
 215         size_t line_len;
 216
 217         if (!line || !*line)
 218                 return -E_UNKNOWN_STAT_ITEM;
 219         line_len = strlen(line);
 220         for (i = 0; i < NUM_STAT_ITEMS; i++) {
 221                 const char *s = status_item_list[i];
 222                 size_t item_len = strlen(s);
 223
 224                 if (line_len > item_len && line[item_len] == ':' &&
 225                                 !strncmp(line, s, item_len))
 226                         return i;
 227         }
 228         return -E_UNKNOWN_STAT_ITEM;
 229 }
 230
 231 /**
 232  * call a custom function for each complete line
 233  *
 234  * \param buf the buffer containing data seperated by newlines
 235  * \param n the number of bytes in \a buf
 236  * \param line_handler the custom function
 237  * \param num upper bound on calls to \a line_handler
 238  *
 239  * If \a line_handler is \p NULL, return number of complete lines in buf.
 240  * Otherwise, call \a line_handler for each complete line, but no more than \a num
 241  * times. If \a num is zero, there is no restriction on how often \a line_handler
 242  * may be called. The rest of the buffer (last chunk containing incomplete line
 243  * if \a num is zero) is moved to the beginning of the buffer.
 244  *
 245  * \return If line_handler is not NULL, this function returns the number
 246  * of bytes not handled to \a line_handler.
 247  */
 248 unsigned for_each_line(char *buf, int n, void (*line_handler)(char *), int num)
 249 {
 250         char *start = buf, *end;
 251         int i, num_lines = 0;
 252
 253         while (start < buf + n) {
 254                 char *next_null;
 255                 char *next_cr;
 256
 257                 next_cr = memchr(start, '\n', buf + n - start);
 258                 next_null = memchr(start, '\0', buf + n - start);
 259                 if (!next_cr && !next_null)
 260                         break;
 261                 if (next_cr && next_null) {
 262                         end = next_cr < next_null? next_cr : next_null;
 263                 } else if (next_null) {
 264                         end = next_null;
 265                 } else
 266                         end = next_cr;
 267                 num_lines++;
 268                 if (line_handler) {
 269                         *end = '\0';
 270                         line_handler(start);
 271                         start = ++end;
 272                         if (num && num_lines >= num)
 273                                 break;
 274                 } else
 275                         start = ++end;
 276         }
 277         if (!line_handler)
 278                 return num_lines;
 279         i = buf + n - start;
 280         if (i && i != n)
 281                 memmove(buf, start, i);
 282         return i;
 283 }
 284