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     return MEMCACHED_TIMEOUT;
  41   }
  42
  43   WATCHPOINT;
  44   /* Imposssible for anything other then -1 */
  45   WATCHPOINT_ASSERT(error == -1);
  46   memcached_quit_server(ptr, server_key, 1);
  47   return MEMCACHED_FAILURE;
  48
  49 }
  50
  51 ssize_t memcached_io_read(memcached_st *ptr, unsigned  int server_key,
  52                           char *buffer, size_t length)
  53 {
  54   char *buffer_ptr;
  55
  56   buffer_ptr= buffer;
  57
  58   while (length)
  59   {
  60     if (!ptr->hosts[server_key].read_buffer_length)
  61     {
  62       size_t data_read;
  63
  64       while (1)
  65       {
  66         data_read= read(ptr->hosts[server_key].fd,
  67                         ptr->hosts[server_key].read_buffer,
  68                         MEMCACHED_MAX_BUFFER);
  69         if (data_read == -1)
  70         {
  71           switch (errno)
  72           {
  73           case EAGAIN:
  74             {
  75               memcached_return rc;
  76               rc= io_wait(ptr, server_key, MEM_READ);
  77
  78               if (rc == MEMCACHED_SUCCESS)
  79                 continue;
  80
  81               memcached_quit_server(ptr, server_key, 1);
  82               return -1;
  83             }
  84           default:
  85             {
  86               memcached_quit_server(ptr, server_key, 1);
  87               ptr->cached_errno= errno;
  88               return -1;
  89             }
  90           }
  91         }
  92         else if (data_read)
  93           break;
  94         /* If zero, just keep looping */
  95       }
  96
  97       ptr->hosts[server_key].read_buffer_length= data_read;
  98       ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
  99     }
 100
 101     *buffer_ptr= *ptr->hosts[server_key].read_ptr;
 102     length--;
 103     ptr->hosts[server_key].read_ptr++;
 104     ptr->hosts[server_key].read_buffer_length--;
 105     buffer_ptr++;
 106   }
 107
 108   return (size_t)(buffer_ptr - buffer);
 109 }
 110
 111 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
 112                         char *buffer, size_t length, char with_flush)
 113 {
 114   unsigned long long x;
 115
 116   for (x= 0; x < length; x++)
 117   {
 118     if (ptr->hosts[server_key].write_ptr == 0)
 119       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 120     WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
 121     *ptr->hosts[server_key].write_ptr= buffer[x];
 122     ptr->hosts[server_key].write_ptr++;
 123     ptr->hosts[server_key].write_buffer_offset++;
 124
 125     if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
 126     {
 127       memcached_return rc;
 128       size_t sent_length;
 129
 130       sent_length= io_flush(ptr, server_key, &rc);
 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     memcached_return rc;
 143     if (io_flush(ptr, server_key, &rc) == -1)
 144       return -1;
 145   }
 146
 147   return length;
 148 }
 149
 150 memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 151 {
 152   close(ptr->hosts[server_key].fd);
 153
 154   return MEMCACHED_SUCCESS;
 155 }
 156
 157 static ssize_t io_flush(memcached_st *ptr, unsigned int server_key,
 158                                   memcached_return *error)
 159 {
 160   size_t sent_length;
 161   size_t return_length;
 162   char *write_ptr= ptr->hosts[server_key].write_buffer;
 163   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 164
 165   *error= MEMCACHED_SUCCESS;
 166
 167   if (ptr->hosts[server_key].write_buffer_offset == 0)
 168     return 0;
 169
 170   return_length= 0;
 171   while (write_length)
 172   {
 173     sent_length= 0;
 174     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 175     {
 176       sent_length= sendto(ptr->hosts[server_key].fd,
 177                           write_ptr, write_length, 0,
 178                           (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr,
 179                           sizeof(struct sockaddr));
 180     }
 181     else
 182     {
 183       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 184                                        write_length)) == -1)
 185       {
 186         switch (errno)
 187         {
 188         case ENOBUFS:
 189           continue;
 190         case EAGAIN:
 191           {
 192             memcached_return rc;
 193             rc= io_wait(ptr, server_key, MEM_WRITE);
 194
 195             if (rc == MEMCACHED_SUCCESS)
 196               continue;
 197
 198             memcached_quit_server(ptr, server_key, 1);
 199             return -1;
 200           }
 201         default:
 202           memcached_quit_server(ptr, server_key, 1);
 203           ptr->cached_errno= errno;
 204           *error= MEMCACHED_ERRNO;
 205           return -1;
 206         }
 207       }
 208     }
 209
 210     write_ptr+= sent_length;
 211     write_length-= sent_length;
 212     return_length+= sent_length;
 213   }
 214
 215   WATCHPOINT_ASSERT(write_length == 0);
 216   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 217   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 218   ptr->hosts[server_key].write_buffer_offset= 0;
 219
 220   return return_length;
 221 }
 222
 223 /*
 224   Eventually we will just kill off the server with the problem.
 225 */
 226 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 227 {
 228   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 229   ptr->hosts[server_key].write_buffer_offset= 0;
 230   memcached_quit(ptr);
 231 }