git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/memcached_hosts.c

   1 #include "common.h"
   2
   3 /* Protoypes (static) */
   4 static memcached_return server_add(memcached_st *ptr, char *hostname,
   5                                    unsigned int port,
   6                                    memcached_connection type);
   7 memcached_return update_continuum(memcached_st *ptr);
   8
   9 #define MEMCACHED_WHEEL_SIZE 1024
  10 #define MEMCACHED_STRIDE 4
  11 static memcached_return rebalance_wheel(memcached_st *ptr)
  12 {
  13   unsigned int x;
  14   unsigned int y;
  15   unsigned int latch;
  16
  17   if (ptr->number_of_hosts > ptr->wheel_count)
  18   {
  19     uint32_t *new_ptr;
  20
  21     if (ptr->call_realloc)
  22       new_ptr= (uint32_t *)ptr->call_realloc(ptr, ptr->wheel, sizeof(uint32_t) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_STRIDE);
  23     else
  24       new_ptr= (uint32_t *)realloc(ptr->wheel, sizeof(uint32_t) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_STRIDE);
  25
  26     if (new_ptr == 0)
  27       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
  28
  29     ptr->wheel= new_ptr;
  30     ptr->wheel_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
  31   }
  32
  33   /* Seed the Wheel */
  34   memset(ptr->wheel, 0, sizeof(uint32_t) * MEMCACHED_STRIDE * ptr->wheel_count);
  35
  36   for (latch= y= x= 0; x < MEMCACHED_STRIDE * ptr->wheel_count; x++, latch++)
  37   {
  38     if (latch == MEMCACHED_STRIDE)
  39     {
  40       y++;
  41       if (y == ptr->number_of_hosts)
  42         y= 0;
  43       latch= 0;
  44     }
  45
  46     ptr->wheel[x]= y;
  47   }
  48
  49   return MEMCACHED_SUCCESS;
  50 }
  51
  52 static int compare_servers(const void *p1, const void *p2)
  53 {
  54   int return_value;
  55   memcached_server_st *a= (memcached_server_st *)p1;
  56   memcached_server_st *b= (memcached_server_st *)p2;
  57
  58   return_value= strcmp(a->hostname, b->hostname);
  59
  60   if (return_value == 0)
  61   {
  62     return_value= (int) (a->port - b->port);
  63   }
  64
  65   return return_value;
  66 }
  67
  68 void sort_hosts(memcached_st *ptr)
  69 {
  70   if (ptr->number_of_hosts)
  71   {
  72     qsort(ptr->hosts, ptr->number_of_hosts, sizeof(memcached_server_st), compare_servers);
  73     ptr->hosts[0].count= ptr->number_of_hosts;
  74   }
  75 }
  76
  77
  78 memcached_return run_distribution(memcached_st *ptr)
  79 {
  80   switch (ptr->distribution)
  81   {
  82   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  83   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  84     return update_continuum(ptr);
  85   case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL:
  86     return rebalance_wheel(ptr);
  87     break;
  88   case MEMCACHED_DISTRIBUTION_MODULA:
  89     if (ptr->flags & MEM_USE_SORT_HOSTS)
  90       sort_hosts(ptr);
  91     break;
  92   default:
  93     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  94   }
  95
  96   return MEMCACHED_SUCCESS;
  97 }
  98
  99 static void host_reset(memcached_st *ptr, memcached_server_st *host,
 100                        char *hostname, unsigned int port,
 101                        memcached_connection type)
 102 {
 103   memset(host,  0, sizeof(memcached_server_st));
 104   strncpy(host->hostname, hostname, MEMCACHED_MAX_HOST_LENGTH - 1);
 105   host->root= ptr ? ptr : NULL;
 106   host->port= port;
 107   host->fd= -1;
 108   host->type= type;
 109   host->read_ptr= host->read_buffer;
 110   if (ptr)
 111     host->next_retry= ptr->retry_timeout;
 112   host->sockaddr_inited= MEMCACHED_NOT_ALLOCATED;
 113 }
 114
 115 void server_list_free(memcached_st *ptr, memcached_server_st *servers)
 116 {
 117   unsigned int x;
 118
 119   if (servers == NULL)
 120     return;
 121
 122   for (x= 0; x < servers->count; x++)
 123     if (servers[x].address_info)
 124       freeaddrinfo(servers[x].address_info);
 125
 126   if (ptr && ptr->call_free)
 127     ptr->call_free(ptr, servers);
 128   else
 129     free(servers);
 130 }
 131
 132 static int continuum_item_cmp(const void *t1, const void *t2)
 133 {
 134   memcached_continuum_item_st *ct1 = (memcached_continuum_item_st *)t1;
 135   memcached_continuum_item_st *ct2 = (memcached_continuum_item_st *)t2;
 136
 137   WATCHPOINT_ASSERT(ct1->value != 153);
 138   if (ct1->value == ct2->value)
 139     return 0;
 140   else if (ct1->value > ct2->value)
 141     return 1;
 142   else
 143     return -1;
 144 }
 145
 146 memcached_return update_continuum(memcached_st *ptr)
 147 {
 148   uint32_t index;
 149   uint32_t host_index;
 150   uint32_t continuum_index= 0;
 151   uint32_t value;
 152   memcached_server_st *list;
 153
 154   if (ptr->number_of_hosts > ptr->continuum_count)
 155   {
 156     memcached_continuum_item_st *new_ptr;
 157
 158     if (ptr->call_realloc)
 159       new_ptr= (memcached_continuum_item_st *)ptr->call_realloc(ptr, ptr->continuum, sizeof(memcached_continuum_item_st) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_POINTS_PER_SERVER);
 160     else
 161       new_ptr= (memcached_continuum_item_st *)realloc(ptr->continuum, sizeof(memcached_continuum_item_st) * (ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION) * MEMCACHED_POINTS_PER_SERVER);
 162
 163     if (new_ptr == 0)
 164       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 165
 166     ptr->continuum= new_ptr;
 167     ptr->continuum_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
 168   }
 169
 170   list = ptr->hosts;
 171   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 172   {
 173     for(index= 1; index <= MEMCACHED_POINTS_PER_SERVER; ++index)
 174     {
 175       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 176       size_t sort_host_length;
 177
 178       sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 179                                  list[host_index].hostname, list[host_index].port, index);
 180       WATCHPOINT_ASSERT(sort_host_length);
 181       value= generate_hash(ptr, sort_host, sort_host_length);
 182       ptr->continuum[continuum_index].index= host_index;
 183       ptr->continuum[continuum_index++].value= value;
 184     }
 185   }
 186
 187   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 188   qsort(ptr->continuum, ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 189 #ifdef HAVE_DEBUG
 190   for (index= 0; index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 191   {
 192     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 193   }
 194 #endif
 195
 196   return MEMCACHED_SUCCESS;
 197 }
 198
 199
 200 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 201 {
 202   unsigned int x;
 203   uint16_t count;
 204   memcached_server_st *new_host_list;
 205
 206   if (!list)
 207     return MEMCACHED_SUCCESS;
 208
 209   count= list[0].count;
 210
 211   if (ptr->call_realloc)
 212     new_host_list=
 213       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 214                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 215   else
 216     new_host_list=
 217       (memcached_server_st *)realloc(ptr->hosts,
 218                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 219
 220   if (!new_host_list)
 221     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 222
 223   ptr->hosts= new_host_list;
 224
 225   for (x= 0; x < count; x++)
 226   {
 227     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 228     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 229                list[x].port, list[x].type);
 230     ptr->number_of_hosts++;
 231   }
 232   ptr->hosts[0].count= ptr->number_of_hosts;
 233
 234   return run_distribution(ptr);
 235 }
 236
 237 memcached_return memcached_server_add_unix_socket(memcached_st *ptr, char *filename)
 238 {
 239   if (!filename)
 240     return MEMCACHED_FAILURE;
 241
 242   return server_add(ptr, filename, 0, MEMCACHED_CONNECTION_UNIX_SOCKET);
 243 }
 244
 245 memcached_return memcached_server_add_udp(memcached_st *ptr,
 246                                           char *hostname,
 247                                           unsigned int port)
 248 {
 249   if (!port)
 250     port= MEMCACHED_DEFAULT_PORT;
 251
 252   if (!hostname)
 253     hostname= "localhost";
 254
 255   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_UDP);
 256 }
 257
 258 memcached_return memcached_server_add(memcached_st *ptr,
 259                                       char *hostname,
 260                                       unsigned int port)
 261 {
 262   if (!port)
 263     port= MEMCACHED_DEFAULT_PORT;
 264
 265   if (!hostname)
 266     hostname= "localhost";
 267
 268   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_TCP);
 269 }
 270
 271 static memcached_return server_add(memcached_st *ptr, char *hostname,
 272                                    unsigned int port,
 273                                    memcached_connection type)
 274 {
 275   memcached_server_st *new_host_list;
 276
 277   if (ptr->call_realloc)
 278     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 279                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 280   else
 281     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 282                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 283   if (new_host_list == NULL)
 284     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 285
 286   ptr->hosts= new_host_list;
 287
 288   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, type);
 289   ptr->number_of_hosts++;
 290   ptr->hosts[0].count= ptr->number_of_hosts;
 291
 292   return run_distribution(ptr);
 293 }
 294
 295 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 296                                                   char *hostname, unsigned int port,
 297                                                   memcached_return *error)
 298 {
 299   unsigned int count;
 300   memcached_server_st *new_host_list;
 301
 302   if (hostname == NULL || error == NULL)
 303     return NULL;
 304
 305   if (!port)
 306     port= MEMCACHED_DEFAULT_PORT;
 307
 308   /* Increment count for hosts */
 309   count= 1;
 310   if (ptr != NULL)
 311   {
 312     count+= ptr[0].count;
 313   }
 314
 315   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 316   if (!new_host_list)
 317   {
 318     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 319     return NULL;
 320   }
 321
 322   host_reset(NULL, &new_host_list[count-1], hostname, port, MEMCACHED_CONNECTION_TCP);
 323
 324   /* Backwards compatibility hack */
 325   new_host_list[0].count= count;
 326
 327   *error= MEMCACHED_SUCCESS;
 328   return new_host_list;
 329 }
 330
 331 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 332 {
 333   if (ptr == NULL)
 334     return 0;
 335
 336   return ptr[0].count;
 337 }
 338
 339 void memcached_server_list_free(memcached_server_st *ptr)
 340 {
 341   server_list_free(NULL, ptr);
 342 }