git.m6w6.name Git - awesomized/libmemcached/blob - lib/memcached_io.c

   1 /*
   2   Basic socket buffered IO
   3 */
   4
   5 #include "common.h"
   6 #include "memcached_io.h"
   7 #include <sys/select.h>
   8 #include <poll.h>
   9
  10 static int io_wait(memcached_st *ptr, unsigned int server_key, unsigned read_or_write)
  11 {
  12   struct pollfd fds[1];
  13   short flags= 0;
  14   int error;
  15   int latch= 0;
  16
  17   if (read_or_write)
  18     flags= POLLOUT |  POLLERR;
  19   else
  20     flags= POLLIN | POLLERR;
  21
  22   memset(&fds, 0, sizeof(struct pollfd));
  23   fds[0].fd= ptr->hosts[server_key].fd;
  24   fds[0].events= flags;
  25
  26   while (latch == 0)
  27   {
  28     error= poll(fds, 1, ptr->poll_timeout);
  29
  30     if (error == 1)
  31       return MEMCACHED_SUCCESS;
  32     else if (error == -1)
  33     {
  34       memcached_quit_server(ptr, server_key, 1);
  35       return MEMCACHED_FAILURE;
  36     }
  37     else if (error)
  38     {
  39       /* This is impossible */
  40       WATCHPOINT_ASSERT(0);
  41       return MEMCACHED_FAILURE;
  42     }
  43     else
  44       latch++;
  45   }
  46
  47   memcached_quit_server(ptr, server_key, 1);
  48
  49   return MEMCACHED_FAILURE; /* Timeout occurred */
  50 }
  51
  52 ssize_t memcached_io_read(memcached_st *ptr, unsigned  int server_key,
  53                           char *buffer, size_t length)
  54 {
  55   char *buffer_ptr;
  56
  57   buffer_ptr= buffer;
  58
  59   while (length)
  60   {
  61     if (!ptr->hosts[server_key].read_buffer_length)
  62     {
  63       size_t data_read;
  64
  65       while (1)
  66       {
  67         if (ptr->flags & MEM_NO_BLOCK)
  68         {
  69           memcached_return rc;
  70
  71           rc= io_wait(ptr, server_key, 0);
  72           if (rc != MEMCACHED_SUCCESS)
  73             return -1;
  74         }
  75
  76         data_read= read(ptr->hosts[server_key].fd,
  77                         ptr->hosts[server_key].read_buffer,
  78                         MEMCACHED_MAX_BUFFER);
  79         if (data_read == -1)
  80         {
  81           switch (errno)
  82           {
  83           case EAGAIN:
  84             break;
  85           default:
  86             {
  87               memcached_quit_server(ptr, server_key, 1);
  88               ptr->cached_errno= errno;
  89               return -1;
  90             }
  91           }
  92         }
  93         else if (data_read)
  94           break;
  95         /* If zero, just keep looping */
  96       }
  97
  98       ptr->hosts[server_key].read_buffer_length= data_read;
  99       ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
 100     }
 101
 102     *buffer_ptr= *ptr->hosts[server_key].read_ptr;
 103     length--;
 104     ptr->hosts[server_key].read_ptr++;
 105     ptr->hosts[server_key].read_buffer_length--;
 106     buffer_ptr++;
 107   }
 108
 109   return (size_t)(buffer_ptr - buffer);
 110 }
 111
 112 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
 113                         char *buffer, size_t length, char with_flush)
 114 {
 115   unsigned long long x;
 116
 117   for (x= 0; x < length; x++)
 118   {
 119     if (ptr->hosts[server_key].write_ptr == 0)
 120       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 121     WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
 122     *ptr->hosts[server_key].write_ptr= buffer[x];
 123     ptr->hosts[server_key].write_ptr++;
 124     ptr->hosts[server_key].write_buffer_offset++;
 125
 126     if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
 127     {
 128       size_t sent_length;
 129
 130       sent_length= memcached_io_flush(ptr, server_key);
 131       if (sent_length == -1)
 132         return -1;
 133
 134       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 135       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 136       ptr->hosts[server_key].write_buffer_offset= 0;
 137     }
 138   }
 139
 140   if (with_flush)
 141   {
 142     if (memcached_io_flush(ptr, server_key) == -1)
 143       return -1;
 144   }
 145
 146   return length;
 147 }
 148
 149 memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 150 {
 151   memcached_return rc;
 152
 153   rc= MEMCACHED_SUCCESS;
 154   if (ptr->flags & MEM_NO_BLOCK)
 155   {
 156     int error;
 157     struct pollfd fds[1];
 158     short flags= 0;
 159
 160     flags= POLLHUP |  POLLERR;
 161
 162     memset(&fds, 0, sizeof(struct pollfd));
 163     fds[0].fd= ptr->hosts[server_key].fd;
 164     fds[0].events= flags;
 165     fds[0].revents= 0;
 166
 167     error= poll(fds, 1, ptr->poll_timeout == -1 ? 100 : ptr->poll_timeout);
 168
 169     if (error == -1)
 170     {
 171       memcached_quit_server(ptr, server_key, 1);
 172       return MEMCACHED_FAILURE;
 173     }
 174     else if (error == 0)
 175       return MEMCACHED_FAILURE; /* Timeout occurred */
 176   }
 177
 178   close(ptr->hosts[server_key].fd);
 179
 180   return rc;
 181 }
 182
 183 ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key)
 184 {
 185   size_t sent_length;
 186   size_t return_length;
 187   char *write_ptr= ptr->hosts[server_key].write_buffer;
 188   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 189   unsigned int loop= 1;
 190
 191   if (ptr->hosts[server_key].write_buffer_offset == 0)
 192     return 0;
 193
 194   return_length= 0;
 195   while (write_length)
 196   {
 197     if (ptr->flags & MEM_NO_BLOCK)
 198     {
 199       memcached_return rc;
 200
 201       rc= io_wait(ptr, server_key, 1);
 202       if (rc != MEMCACHED_SUCCESS)
 203         return -1;
 204     }
 205
 206     sent_length= 0;
 207     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 208     {
 209       sent_length= sendto(ptr->hosts[server_key].fd,
 210                           write_ptr, write_length, 0,
 211                           (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr,
 212                           sizeof(struct sockaddr));
 213     }
 214     else
 215     {
 216       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 217                                        write_length)) == -1)
 218       {
 219         switch (errno)
 220         {
 221         case ENOBUFS:
 222         case EAGAIN:
 223           WATCHPOINT;
 224           continue;
 225           if (loop < 100)
 226           {
 227             loop++;
 228             break;
 229           }
 230           /* Yes, we want to fall through */
 231         default:
 232           memcached_quit_server(ptr, server_key, 1);
 233           ptr->cached_errno= errno;
 234           return -1;
 235         }
 236       }
 237     }
 238
 239     write_ptr+= sent_length;
 240     write_length-= sent_length;
 241     return_length+= sent_length;
 242   }
 243
 244   WATCHPOINT_ASSERT(write_length == 0);
 245   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 246   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 247   ptr->hosts[server_key].write_buffer_offset= 0;
 248
 249   return return_length;
 250 }
 251
 252 /*
 253   Eventually we will just kill off the server with the problem.
 254 */
 255 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 256 {
 257   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 258   ptr->hosts[server_key].write_buffer_offset= 0;
 259   memcached_quit(ptr);
 260 }