src/send.c

   1 /* libmpdclient
   2    (c) 2003-2009 The Music Player Daemon Project
   3    This project's homepage is: http://www.musicpd.org
   4
   5    Redistribution and use in source and binary forms, with or without
   6    modification, are permitted provided that the following conditions
   7    are met:
   8
   9    - Redistributions of source code must retain the above copyright
  10    notice, this list of conditions and the following disclaimer.
  11
  12    - Redistributions in binary form must reproduce the above copyright
  13    notice, this list of conditions and the following disclaimer in the
  14    documentation and/or other materials provided with the distribution.
  15
  16    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  20    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  21    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  22    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  23    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  24    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  25    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  26    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27 */
  28
  29 #include <mpd/send.h>
  30 #include "internal.h"
  31
  32 #include <stdarg.h>
  33 #include <string.h>
  34
  35 static bool
  36 mpd_can_send(struct mpd_connection *connection)
  37 {
  38         if (!mpd_socket_defined(&connection->socket)) {
  39                 mpd_error_code(&connection->error, MPD_ERROR_CONNCLOSED);
  40                 mpd_error_message(&connection->error, "connection closed");
  41                 return false;
  42         }
  43
  44         if (!connection->doneProcessing && !connection->commandList) {
  45                 mpd_error_code(&connection->error, MPD_ERROR_STATE);
  46                 mpd_error_message(&connection->error,
  47                                   "not done processing current command");
  48                 return false;
  49         }
  50
  51         return true;
  52 }
  53
  54 bool
  55 mpd_send(struct mpd_connection *connection, const void *p, size_t length)
  56 {
  57         if (!mpd_can_send(connection))
  58                 return false;
  59
  60         mpd_clear_error(connection);
  61
  62         return mpd_socket_send(&connection->socket, p, length,
  63                                &connection->error);
  64 }
  65
  66 /**
  67  * Append a string to the buffer, and escape special characters.
  68  */
  69 static char *
  70 escape(char *dest, char *end, const char *value)
  71 {
  72         while (*value != 0) {
  73                 char ch = *value++;
  74
  75                 if (dest >= end)
  76                         return NULL;
  77
  78                 if (ch == '"' || ch == '\\') {
  79                         *dest++ = '\\';
  80
  81                         if (dest >= end)
  82                                 return NULL;
  83                 }
  84
  85                 *dest++ = ch;
  86         }
  87
  88         return dest;
  89 }
  90
  91 /**
  92  * Enclose a string in double quotes, and escape special characters.
  93  */
  94 static char *
  95 quote(char *dest, char *end, const char *value)
  96 {
  97         if (dest >= end)
  98                 return NULL;
  99
 100         *dest++ = '"';
 101
 102         dest = escape(dest, end, value);
 103
 104         if (dest == NULL || dest >= end)
 105                 return NULL;
 106
 107         *dest++ = '"';
 108
 109         return dest;
 110 }
 111
 112 bool
 113 mpd_send_command(struct mpd_connection *connection, const char *command, ...)
 114 {
 115         char buffer[1024];
 116         size_t length;
 117         va_list ap;
 118         const char *p;
 119         bool ret;
 120
 121         if (!mpd_can_send(connection))
 122                 return false;
 123
 124         length = strlen(command);
 125         if (length + 1 >= sizeof(buffer)) {
 126                 mpd_error_code(&connection->error, MPD_ERROR_ARG);
 127                 mpd_error_message(&connection->error, "command too long");
 128                 return false;
 129         }
 130
 131         memcpy(buffer, command, length);
 132
 133         va_start(ap, command);
 134
 135         while ((p = va_arg(ap, const char *)) != NULL) {
 136                 assert(length < sizeof(buffer));
 137
 138                 buffer[length++] = ' ';
 139
 140                 p = quote(buffer + length, buffer + sizeof(buffer), p);
 141                 assert(p == NULL ||
 142                        (p >= buffer && p <= buffer + sizeof(buffer)));
 143                 if (p == NULL || p >= buffer + sizeof(buffer)) {
 144                         mpd_error_code(&connection->error, MPD_ERROR_ARG);
 145                         mpd_error_message(&connection->error,
 146                                           "argument list too long");
 147                         return false;
 148                 }
 149
 150                 length = p - buffer;
 151         }
 152
 153         va_end(ap);
 154
 155         assert(length < sizeof(buffer));
 156         buffer[length++] = '\n';
 157
 158         ret = mpd_send(connection, buffer, length);
 159         if (!ret)
 160                 return false;
 161
 162         if (!connection->commandList)
 163                 connection->doneProcessing = false;
 164         else if (connection->commandList == COMMAND_LIST_OK)
 165                 connection->listOks++;
 166
 167         return true;
 168 }