git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/dump.cc

   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  Libmemcached library
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
   6  *
   7  *  Redistribution and use in source and binary forms, with or without
   8  *  modification, are permitted provided that the following conditions are
   9  *  met:
  10  *
  11  *      * Redistributions of source code must retain the above copyright
  12  *  notice, this list of conditions and the following disclaimer.
  13  *
  14  *      * Redistributions in binary form must reproduce the above
  15  *  copyright notice, this list of conditions and the following disclaimer
  16  *  in the documentation and/or other materials provided with the
  17  *  distribution.
  18  *
  19  *      * The names of its contributors may not be used to endorse or
  20  *  promote products derived from this software without specific prior
  21  *  written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  29  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  30  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  31  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  33  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  *
  35  */
  36
  37 /*
  38   We use this to dump all keys.
  39
  40   At this point we only support a callback method. This could be optimized by first
  41   calling items and finding active slabs. For the moment though we just loop through
  42   all slabs on servers and "grab" the keys.
  43 */
  44
  45 #include <libmemcached/common.h>
  46
  47 static memcached_return_t ascii_dump(Memcached *memc, memcached_dump_fn *callback, void *context, uint32_t number_of_callbacks)
  48 {
  49   /* MAX_NUMBER_OF_SLAB_CLASSES is defined to 200 in Memcached 1.4.10 */
  50   for (uint32_t x= 0; x < 200; x++)
  51   {
  52     char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  53     int buffer_length= snprintf(buffer, sizeof(buffer), "%u", x);
  54     if (size_t(buffer_length) >= sizeof(buffer) or buffer_length < 0)
  55     {
  56       return memcached_set_error(*memc, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT,
  57                                  memcached_literal_param("snprintf(MEMCACHED_DEFAULT_COMMAND_SIZE)"));
  58     }
  59
  60     // @NOTE the hard coded zero means "no limit"
  61     libmemcached_io_vector_st vector[]=
  62     {
  63       { memcached_literal_param("stats cachedump ") },
  64       { buffer, size_t(buffer_length) },
  65       { memcached_literal_param(" 0\r\n") }
  66     };
  67
  68     // Send message to all servers
  69     for (uint32_t server_key= 0; server_key < memcached_server_count(memc); server_key++)
  70     {
  71       memcached_instance_st* instance= memcached_instance_fetch(memc, server_key);
  72
  73       memcached_return_t vdo_rc;
  74       if (memcached_failed((vdo_rc= memcached_vdo(instance, vector, 3, true))))
  75       {
  76         return vdo_rc;
  77       }
  78     }
  79
  80     // Collect the returned items
  81     memcached_instance_st* instance;
  82     memcached_return_t read_ret= MEMCACHED_SUCCESS;
  83     while ((instance= memcached_io_get_readable_server(memc, read_ret)))
  84     {
  85       memcached_return_t response_rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
  86       if (response_rc == MEMCACHED_ITEM)
  87       {
  88         char *string_ptr, *end_ptr;
  89
  90         string_ptr= buffer;
  91         string_ptr+= 5; /* Move past ITEM */
  92
  93         for (end_ptr= string_ptr; isgraph(*end_ptr); end_ptr++) {} ;
  94
  95         char *key= string_ptr;
  96         key[(size_t)(end_ptr-string_ptr)]= 0;
  97
  98         for (uint32_t callback_counter= 0; callback_counter < number_of_callbacks; callback_counter++)
  99         {
 100           memcached_return_t callback_rc= (*callback[callback_counter])(memc, key, (size_t)(end_ptr-string_ptr), context);
 101           if (callback_rc != MEMCACHED_SUCCESS)
 102           {
 103             // @todo build up a message for the error from the value
 104             memcached_set_error(*instance, callback_rc, MEMCACHED_AT);
 105             break;
 106           }
 107         }
 108       }
 109       else if (response_rc == MEMCACHED_END)
 110       {
 111         // All items have been returned
 112       }
 113       else if (response_rc == MEMCACHED_SERVER_ERROR)
 114       {
 115         /* If we try to request stats cachedump for a slab class that is too big
 116          * the server will return an incorrect error message:
 117          * "MEMCACHED_SERVER_ERROR failed to allocate memory"
 118          * This isn't really a fatal error, so let's just skip it. I want to
 119          * fix the return value from the memcached server to a CLIENT_ERROR,
 120          * so let's add support for that as well right now.
 121        */
 122         assert(response_rc == MEMCACHED_SUCCESS); // Just fail
 123         return response_rc;
 124       }
 125       else if (response_rc == MEMCACHED_CLIENT_ERROR)
 126       {
 127         /* The maximum number of slabs has changed in the past (currently 1<<6-1),
 128          * so ignore any client errors complaining about an illegal slab id.
 129          */
 130         if (0 == strncmp(buffer, "CLIENT_ERROR Illegal slab id", sizeof("CLIENT_ERROR Illegal slab id") - 1)) {
 131           memcached_error_free(*instance);
 132           memcached_error_free(*memc);
 133         } else {
 134           return response_rc;
 135         }
 136       }
 137       else
 138       {
 139         // IO error of some sort must have occurred
 140         return response_rc;
 141       }
 142     }
 143   }
 144
 145   return memcached_has_current_error(*memc) ? MEMCACHED_SOME_ERRORS : MEMCACHED_SUCCESS;
 146 }
 147
 148 memcached_return_t memcached_dump(memcached_st *shell, memcached_dump_fn *callback, void *context, uint32_t number_of_callbacks)
 149 {
 150   Memcached* ptr= memcached2Memcached(shell);
 151   memcached_return_t rc;
 152   if (memcached_failed(rc= initialize_query(ptr, true)))
 153   {
 154     return rc;
 155   }
 156
 157   /*
 158     No support for Binary protocol yet
 159     @todo Fix this so that we just flush, switch to ascii, and then go back to binary.
 160   */
 161   if (memcached_is_binary(ptr))
 162   {
 163     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT, memcached_literal_param("Binary protocol is not supported for memcached_dump()"));
 164   }
 165
 166   return ascii_dump(ptr, callback, context, number_of_callbacks);
 167 }