stat.c

   1 /*
   2  * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /**
   8  *  \file stat.c Functions used for sending/receiving the status of para_server
   9  *  and para_audiod.
  10  */
  11
  12
  13 #include <sys/types.h>
  14 #include <dirent.h>
  15
  16 #include "para.h"
  17 #include "close_on_fork.h"
  18 #include "list.h"
  19 #include "error.h"
  20 #include "string.h"
  21 #include "fd.h"
  22
  23 /** The maximal number of simultaneous connections. */
  24 #define MAX_STAT_CLIENTS 50
  25
  26 extern char *stat_item_values[NUM_STAT_ITEMS];
  27
  28 /** Flags used for the stat command of para_audiod. */
  29 enum stat_client_flags {
  30         /** Enable parser-friendly output. */
  31         SCF_PARSER_FRIENDLY = 1,
  32 };
  33
  34 /**
  35  * Describes a status client of para_audiod.
  36  *
  37  * There's one such structure per audiod client that sent the 'stat' command.
  38  *
  39  * A status client is identified by its file descriptor.  para_audiod
  40  * keeps a list of connected status clients.
  41  */
  42 struct stat_client {
  43         /** The stat client's file descriptor. */
  44         int fd;
  45         /** Bitmask of those status items the client is interested in. */
  46         uint64_t item_mask;
  47         /** See \ref stat_client flags. s*/
  48         unsigned flags;
  49         /** Its entry in the list of stat clients. */
  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 /** The list of all status items used by para_{server,audiod,gui}. */
  58 const char *status_item_list[] = {STATUS_ITEM_ARRAY};
  59
  60 static void dump_stat_client_list(void)
  61 {
  62         struct stat_client *sc;
  63
  64         if (!initialized)
  65                 return;
  66         list_for_each_entry(sc, &client_list, node)
  67                 PARA_INFO_LOG("stat client on fd %d\n", sc->fd);
  68 }
  69 /**
  70  * Add a status client to the list.
  71  *
  72  * \param fd The file descriptor of the client.
  73  * \param mask Bitfield of status items for this client.
  74  * \param parser_friendly Enable parser-friendly output mode.
  75  *
  76  * Only those status items having the bit set in \a mask will be
  77  * sent to the client.
  78  *
  79  * \return Positive value on success, or -E_TOO_MANY_CLIENTS if
  80  * the number of connected clients exceeds #MAX_STAT_CLIENTS.
  81  */
  82 int stat_client_add(int fd, uint64_t mask, int parser_friendly)
  83 {
  84         struct stat_client *new_client;
  85
  86         if (num_clients >= MAX_STAT_CLIENTS) {
  87                 PARA_ERROR_LOG("maximal number of stat clients (%d) exceeded\n",
  88                         MAX_STAT_CLIENTS);
  89                 return -E_TOO_MANY_CLIENTS;
  90         }
  91         if (!initialized) {
  92                 INIT_LIST_HEAD(&client_list);
  93                 initialized = 1;
  94         }
  95         PARA_INFO_LOG("adding client on fd %d\n", fd);
  96         new_client = para_calloc(sizeof(struct stat_client));
  97         new_client->fd = fd;
  98         new_client->item_mask = mask;
  99         if (parser_friendly)
 100                 new_client->flags = SCF_PARSER_FRIENDLY;
 101         para_list_add(&new_client->node, &client_list);
 102         dump_stat_client_list();
 103         num_clients++;
 104         return 1;
 105 }
 106 /**
 107  * Write a message to all connected status clients.
 108  *
 109  * \param item_num The number of the status item of \a msg.
 110  *
 111  * On write errors, remove the status client from the client list and close its
 112  * file descriptor.
 113  */
 114 void stat_client_write_item(int item_num)
 115 {
 116         struct stat_client *sc, *tmp;
 117         struct para_buffer pb = {.flags = 0};
 118         struct para_buffer pfpb = {.flags = PBF_SIZE_PREFIX};
 119         const uint64_t one = 1;
 120
 121         if (!initialized)
 122                 return;
 123         list_for_each_entry_safe(sc, tmp, &client_list, node) {
 124                 int fd = sc->fd, ret;
 125
 126                 if (!((one << item_num) & sc->item_mask))
 127                         continue;
 128                 if (write_ok(fd) > 0) {
 129                         struct para_buffer *b =
 130                                 (sc->flags & SCF_PARSER_FRIENDLY)? &pfpb : &pb;
 131                         char *msg = stat_item_values[item_num];
 132                         if (!b->buf)
 133                                 WRITE_STATUS_ITEM(b, item_num, "%s\n",
 134                                         msg? msg : "");
 135                         ret = write(fd, b->buf, b->offset);
 136                         if (ret == b->offset)
 137                                 continue;
 138                 }
 139                 /* write error or fd not ready for writing */
 140                 close(fd);
 141                 num_clients--;
 142                 PARA_INFO_LOG("deleting client on fd %d\n", fd);
 143                 list_del(&sc->node);
 144                 free(sc);
 145                 dump_stat_client_list();
 146         }
 147         free(pb.buf);
 148         free(pfpb.buf);
 149 //      if (num_clients)
 150 //              PARA_DEBUG_LOG("%d client(s)\n", num_clients);
 151 }
 152
 153 /**
 154  * Check if string is a known status item.
 155  *
 156  * \param item Buffer containing the text to check.
 157  *
 158  * \return If \a item is a valid status item, the number of that status item is
 159  * returned. Otherwise, this function returns \p -E_UNKNOWN_STAT_ITEM.
 160  */
 161 int stat_item_valid(const char *item)
 162 {
 163         int i;
 164         if (!item || !*item) {
 165                 PARA_ERROR_LOG("%s\n", "no item");
 166                 return -E_UNKNOWN_STAT_ITEM;
 167         }
 168         FOR_EACH_STATUS_ITEM(i)
 169                 if (!strcmp(status_item_list[i], item))
 170                         return i;
 171         PARA_ERROR_LOG("invalid stat item: %s\n", item);
 172         return -E_UNKNOWN_STAT_ITEM;
 173 }
 174
 175 /** The minimal length of a status item buffer. */
 176 #define MIN_STAT_ITEM_LEN 9 /* 5 + 2 + 2, e.g. '0005 00:\n' */
 177
 178 /**
 179  * Call a function for each complete status item of a buffer.
 180  *
 181  * \param item_buf The source buffer.
 182  * \param num_bytes The length of \a buf.
 183  * \param item_handler Function to call for each complete item.
 184  *
 185  * \return Negative on errors, the number of bytes _not_ passed to \a
 186  * item_handler.
 187  *
 188  * Status items are expected in the format used by parser-friendly output mode
 189  * of the stat command of para_client/para_audioc.
 190  */
 191 int for_each_stat_item(char *item_buf, size_t num_bytes,
 192         int (*item_handler)(int, char *))
 193 {
 194         char *buf = item_buf;
 195         int len = num_bytes;
 196
 197         for (;;) {
 198                 int i, ret, item_len, item_num = 0;
 199                 if (len < MIN_STAT_ITEM_LEN)
 200                         break;
 201                 ret = read_size_header(buf);
 202                 if (ret < 0)
 203                         return ret;
 204                 item_len = ret;
 205                 if (item_len > len - 5) /* item not complete */
 206                         break;
 207                 for (i = 0; i < 2; i++) {
 208                         unsigned char c = buf[5 + i];
 209                         item_num <<= 4;
 210                         if (c >= '0' && c <= '9') {
 211                                 item_num += c - '0';
 212                                 continue;
 213                         }
 214                         if (c >= 'a' && c <= 'f') {
 215                                 item_num += c - 'a' + 10;
 216                                 continue;
 217                         }
 218                         return -E_STAT_ITEM_PARSE;
 219                 }
 220                 if (buf[7] != ':' || buf[5 + item_len - 1] != '\n')
 221                         return -E_STAT_ITEM_PARSE;
 222                 buf[5 + item_len - 1] = '\0';
 223                 if (item_num >= NUM_STAT_ITEMS)
 224                         PARA_WARNING_LOG("unknown status item %d: %s\n",
 225                                 item_num, buf + 8);
 226                 else {
 227                         ret = item_handler(item_num, buf + 8);
 228                         if (ret < 0)
 229                                 return ret;
 230                 }
 231                 buf += 5 + item_len;
 232                 len -= 5 + item_len;
 233                 assert(len >= 0 && buf <= item_buf + num_bytes);
 234         }
 235         assert(len >= 0);
 236         if (len && len != num_bytes)
 237                 memmove(item_buf, item_buf + num_bytes - len, len);
 238         return len;
 239 }