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     {
 125       freeaddrinfo(servers[x].address_info);
 126       servers[x].address_info= NULL;
 127     }
 128
 129   if (ptr && ptr->call_free)
 130     ptr->call_free(ptr, servers);
 131   else
 132     free(servers);
 133 }
 134
 135 static int continuum_item_cmp(const void *t1, const void *t2)
 136 {
 137   memcached_continuum_item_st *ct1 = (memcached_continuum_item_st *)t1;
 138   memcached_continuum_item_st *ct2 = (memcached_continuum_item_st *)t2;
 139
 140   WATCHPOINT_ASSERT(ct1->value != 153);
 141   if (ct1->value == ct2->value)
 142     return 0;
 143   else if (ct1->value > ct2->value)
 144     return 1;
 145   else
 146     return -1;
 147 }
 148
 149 memcached_return update_continuum(memcached_st *ptr)
 150 {
 151   uint32_t index;
 152   uint32_t host_index;
 153   uint32_t continuum_index= 0;
 154   uint32_t value;
 155   memcached_server_st *list;
 156
 157   if (ptr->number_of_hosts > ptr->continuum_count)
 158   {
 159     memcached_continuum_item_st *new_ptr;
 160
 161     if (ptr->call_realloc)
 162       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);
 163     else
 164       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);
 165
 166     if (new_ptr == 0)
 167       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 168
 169     ptr->continuum= new_ptr;
 170     ptr->continuum_count= ptr->number_of_hosts + MEMCACHED_CONTINUUM_ADDITION;
 171   }
 172
 173   list = ptr->hosts;
 174   for (host_index = 0; host_index < ptr->number_of_hosts; ++host_index)
 175   {
 176     for(index= 1; index <= MEMCACHED_POINTS_PER_SERVER; ++index)
 177     {
 178       char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 179       size_t sort_host_length;
 180
 181       sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH, "%s:%d-%d",
 182                                  list[host_index].hostname, list[host_index].port, index);
 183       WATCHPOINT_ASSERT(sort_host_length);
 184       value= generate_hash(ptr, sort_host, sort_host_length);
 185       ptr->continuum[continuum_index].index= host_index;
 186       ptr->continuum[continuum_index++].value= value;
 187     }
 188   }
 189
 190   WATCHPOINT_ASSERT(ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 191   qsort(ptr->continuum, ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 192 #ifdef HAVE_DEBUG
 193   for (index= 0; index < ((ptr->number_of_hosts * MEMCACHED_POINTS_PER_SERVER) - 1); index++)
 194   {
 195     WATCHPOINT_ASSERT(ptr->continuum[index].value <= ptr->continuum[index + 1].value);
 196   }
 197 #endif
 198
 199   return MEMCACHED_SUCCESS;
 200 }
 201
 202
 203 memcached_return memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 204 {
 205   unsigned int x;
 206   uint16_t count;
 207   memcached_server_st *new_host_list;
 208
 209   if (!list)
 210     return MEMCACHED_SUCCESS;
 211
 212   count= list[0].count;
 213
 214   if (ptr->call_realloc)
 215     new_host_list=
 216       (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 217                                                sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 218   else
 219     new_host_list=
 220       (memcached_server_st *)realloc(ptr->hosts,
 221                                      sizeof(memcached_server_st) * (count + ptr->number_of_hosts));
 222
 223   if (!new_host_list)
 224   {
 225     assert(0);
 226     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 227   }
 228
 229   ptr->hosts= new_host_list;
 230
 231   for (x= 0; x < count; x++)
 232   {
 233     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 234     host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], list[x].hostname,
 235                list[x].port, list[x].type);
 236     ptr->number_of_hosts++;
 237   }
 238   ptr->hosts[0].count= ptr->number_of_hosts;
 239
 240   return run_distribution(ptr);
 241 }
 242
 243 memcached_return memcached_server_add_unix_socket(memcached_st *ptr, char *filename)
 244 {
 245   if (!filename)
 246     return MEMCACHED_FAILURE;
 247
 248   return server_add(ptr, filename, 0, MEMCACHED_CONNECTION_UNIX_SOCKET);
 249 }
 250
 251 memcached_return memcached_server_add_udp(memcached_st *ptr,
 252                                           char *hostname,
 253                                           unsigned int port)
 254 {
 255   if (!port)
 256     port= MEMCACHED_DEFAULT_PORT;
 257
 258   if (!hostname)
 259     hostname= "localhost";
 260
 261   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_UDP);
 262 }
 263
 264 memcached_return memcached_server_add(memcached_st *ptr,
 265                                       char *hostname,
 266                                       unsigned int port)
 267 {
 268   if (!port)
 269     port= MEMCACHED_DEFAULT_PORT;
 270
 271   if (!hostname)
 272     hostname= "localhost";
 273
 274   return server_add(ptr, hostname, port, MEMCACHED_CONNECTION_TCP);
 275 }
 276
 277 static memcached_return server_add(memcached_st *ptr, char *hostname,
 278                                    unsigned int port,
 279                                    memcached_connection type)
 280 {
 281   memcached_server_st *new_host_list;
 282
 283   if (ptr->call_realloc)
 284     new_host_list= (memcached_server_st *)ptr->call_realloc(ptr, ptr->hosts,
 285                                                             sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 286   else
 287     new_host_list= (memcached_server_st *)realloc(ptr->hosts,
 288                                                   sizeof(memcached_server_st) * (ptr->number_of_hosts+1));
 289   if (new_host_list == NULL)
 290     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 291
 292   ptr->hosts= new_host_list;
 293
 294   host_reset(ptr, &ptr->hosts[ptr->number_of_hosts], hostname, port, type);
 295   ptr->number_of_hosts++;
 296   ptr->hosts[0].count= ptr->number_of_hosts;
 297
 298   return run_distribution(ptr);
 299 }
 300
 301 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 302                                                   char *hostname, unsigned int port,
 303                                                   memcached_return *error)
 304 {
 305   unsigned int count;
 306   memcached_server_st *new_host_list;
 307
 308   if (hostname == NULL || error == NULL)
 309     return NULL;
 310
 311   if (!port)
 312     port= MEMCACHED_DEFAULT_PORT;
 313
 314   /* Increment count for hosts */
 315   count= 1;
 316   if (ptr != NULL)
 317   {
 318     count+= ptr[0].count;
 319   }
 320
 321   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 322   if (!new_host_list)
 323   {
 324     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 325     return NULL;
 326   }
 327
 328   host_reset(NULL, &new_host_list[count-1], hostname, port, MEMCACHED_CONNECTION_TCP);
 329
 330   /* Backwards compatibility hack */
 331   new_host_list[0].count= count;
 332
 333   *error= MEMCACHED_SUCCESS;
 334   return new_host_list;
 335 }
 336
 337 unsigned int memcached_server_list_count(memcached_server_st *ptr)
 338 {
 339   if (ptr == NULL)
 340     return 0;
 341
 342   return ptr[0].count;
 343 }
 344
 345 void memcached_server_list_free(memcached_server_st *ptr)
 346 {
 347   server_list_free(NULL, ptr);
 348 }