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 typedef enum {
  11   MEM_READ,
  12   MEM_WRITE,
  13 } memc_read_or_write;
  14
  15 static ssize_t io_flush(memcached_st *ptr, unsigned int server_key,
  16                                   memcached_return *error);
  17
  18 static memcached_return io_wait(memcached_st *ptr, unsigned int server_key,
  19                                 memc_read_or_write read_or_write)
  20 {
  21   struct pollfd fds[1];
  22   short flags= 0;
  23   int error;
  24
  25   if (read_or_write == MEM_WRITE) /* write */
  26     flags= POLLOUT |  POLLERR;
  27   else
  28     flags= POLLIN | POLLERR;
  29
  30   memset(&fds, 0, sizeof(struct pollfd));
  31   fds[0].fd= ptr->hosts[server_key].fd;
  32   fds[0].events= flags;
  33
  34   error= poll(fds, 1, ptr->poll_timeout);
  35
  36   if (error == 1)
  37     return MEMCACHED_SUCCESS;
  38   else if (error == 0)
  39   {
  40     WATCHPOINT_NUMBER(read_or_write);
  41     return MEMCACHED_TIMEOUT;
  42   }
  43
  44   WATCHPOINT;
  45   /* Imposssible for anything other then -1 */
  46   WATCHPOINT_ASSERT(error == -1);
  47   memcached_quit_server(ptr, server_key, 1);
  48   return MEMCACHED_FAILURE;
  49
  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         data_read= read(ptr->hosts[server_key].fd,
  68                         ptr->hosts[server_key].read_buffer,
  69                         MEMCACHED_MAX_BUFFER);
  70         if (data_read == -1)
  71         {
  72           switch (errno)
  73           {
  74           case EAGAIN:
  75             {
  76               memcached_return rc;
  77               rc= io_wait(ptr, server_key, MEM_READ);
  78
  79               if (rc == MEMCACHED_SUCCESS)
  80                 continue;
  81
  82               memcached_quit_server(ptr, server_key, 1);
  83               return -1;
  84             }
  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       memcached_return rc;
 129       size_t sent_length;
 130
 131       sent_length= io_flush(ptr, server_key, &rc);
 132       if (sent_length == -1)
 133         return -1;
 134
 135       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 136       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 137       ptr->hosts[server_key].write_buffer_offset= 0;
 138     }
 139   }
 140
 141   if (with_flush)
 142   {
 143     memcached_return rc;
 144     if (io_flush(ptr, server_key, &rc) == -1)
 145       return -1;
 146   }
 147
 148   return length;
 149 }
 150
 151 memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 152 {
 153   close(ptr->hosts[server_key].fd);
 154
 155   return MEMCACHED_SUCCESS;
 156 }
 157
 158 static ssize_t io_flush(memcached_st *ptr, unsigned int server_key,
 159                                   memcached_return *error)
 160 {
 161   size_t sent_length;
 162   size_t return_length;
 163   char *write_ptr= ptr->hosts[server_key].write_buffer;
 164   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 165
 166   *error= MEMCACHED_SUCCESS;
 167
 168   if (ptr->hosts[server_key].write_buffer_offset == 0)
 169     return 0;
 170
 171   return_length= 0;
 172   while (write_length)
 173   {
 174     sent_length= 0;
 175     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 176     {
 177       sent_length= sendto(ptr->hosts[server_key].fd,
 178                           write_ptr, write_length, 0,
 179                           (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr,
 180                           sizeof(struct sockaddr));
 181     }
 182     else
 183     {
 184       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 185                                        write_length)) == -1)
 186       {
 187         switch (errno)
 188         {
 189         case ENOBUFS:
 190           continue;
 191         case EAGAIN:
 192           {
 193             memcached_return rc;
 194             rc= io_wait(ptr, server_key, MEM_WRITE);
 195
 196             if (rc == MEMCACHED_SUCCESS)
 197               continue;
 198
 199             memcached_quit_server(ptr, server_key, 1);
 200             return -1;
 201           }
 202         default:
 203           memcached_quit_server(ptr, server_key, 1);
 204           ptr->cached_errno= errno;
 205           *error= MEMCACHED_ERRNO;
 206           return -1;
 207         }
 208       }
 209     }
 210
 211     write_ptr+= sent_length;
 212     write_length-= sent_length;
 213     return_length+= sent_length;
 214   }
 215
 216   WATCHPOINT_ASSERT(write_length == 0);
 217   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 218   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 219   ptr->hosts[server_key].write_buffer_offset= 0;
 220
 221   return return_length;
 222 }
 223
 224 /*
 225   Eventually we will just kill off the server with the problem.
 226 */
 227 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 228 {
 229   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 230   ptr->hosts[server_key].write_buffer_offset= 0;
 231   memcached_quit(ptr);
 232 }