git.m6w6.name Git - m6w6/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
  48   return MEMCACHED_FAILURE;
  49
  50 }
  51
  52 void memcached_io_preread(memcached_st *ptr)
  53 {
  54   unsigned int x;
  55
  56   return;
  57
  58   for (x= 0; x < ptr->number_of_hosts; x++)
  59   {
  60     if (ptr->hosts[x].cursor_active &&
  61         ptr->hosts[x].read_data_length < MEMCACHED_MAX_BUFFER )
  62     {
  63       size_t data_read;
  64
  65       data_read= read(ptr->hosts[x].fd,
  66                       ptr->hosts[x].read_ptr + ptr->hosts[x].read_data_length,
  67                       MEMCACHED_MAX_BUFFER - ptr->hosts[x].read_data_length);
  68       if (data_read == -1)
  69         continue;
  70
  71       ptr->hosts[x].read_buffer_length+= data_read;
  72       ptr->hosts[x].read_data_length+= data_read;
  73     }
  74   }
  75 }
  76
  77 ssize_t memcached_io_read(memcached_st *ptr, unsigned  int server_key,
  78                           char *buffer, size_t length)
  79 {
  80   char *buffer_ptr;
  81
  82   buffer_ptr= buffer;
  83
  84   while (length)
  85   {
  86     if (!ptr->hosts[server_key].read_buffer_length)
  87     {
  88       size_t data_read;
  89
  90       while (1)
  91       {
  92         data_read= read(ptr->hosts[server_key].fd,
  93                         ptr->hosts[server_key].read_buffer,
  94                         MEMCACHED_MAX_BUFFER);
  95         if (data_read == -1)
  96         {
  97           switch (errno)
  98           {
  99           case EAGAIN:
 100             {
 101               memcached_return rc;
 102
 103               rc= io_wait(ptr, server_key, MEM_READ);
 104
 105               if (rc == MEMCACHED_SUCCESS)
 106                 continue;
 107
 108               memcached_quit_server(ptr, server_key, 1);
 109               return -1;
 110             }
 111           default:
 112             {
 113               memcached_quit_server(ptr, server_key, 1);
 114               ptr->cached_errno= errno;
 115               return -1;
 116             }
 117           }
 118         }
 119         else if (data_read)
 120           break;
 121         /* If zero, just keep looping */
 122       }
 123
 124       ptr->hosts[server_key].read_data_length= data_read;
 125       ptr->hosts[server_key].read_buffer_length= data_read;
 126       ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
 127     }
 128
 129     if (length > 1)
 130     {
 131       size_t difference;
 132
 133       difference= (length > ptr->hosts[server_key].read_buffer_length) ? ptr->hosts[server_key].read_buffer_length : length;
 134
 135       memcpy(buffer_ptr, ptr->hosts[server_key].read_ptr, difference);
 136       length -= difference;
 137       ptr->hosts[server_key].read_ptr+= difference;
 138       ptr->hosts[server_key].read_buffer_length-= difference;
 139       buffer_ptr+= difference;
 140     }
 141     else
 142     {
 143       *buffer_ptr= *ptr->hosts[server_key].read_ptr;
 144       length--;
 145       ptr->hosts[server_key].read_ptr++;
 146       ptr->hosts[server_key].read_buffer_length--;
 147       buffer_ptr++;
 148     }
 149   }
 150
 151   return (size_t)(buffer_ptr - buffer);
 152 }
 153
 154 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
 155                         char *buffer, size_t length, char with_flush)
 156 {
 157   unsigned long long x;
 158
 159   for (x= 0; x < length; x++)
 160   {
 161     if (ptr->hosts[server_key].write_ptr == 0)
 162       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 163     WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
 164     *ptr->hosts[server_key].write_ptr= buffer[x];
 165     ptr->hosts[server_key].write_ptr++;
 166     ptr->hosts[server_key].write_buffer_offset++;
 167
 168     if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
 169     {
 170       memcached_return rc;
 171       size_t sent_length;
 172
 173       sent_length= io_flush(ptr, server_key, &rc);
 174       if (sent_length == -1)
 175         return -1;
 176
 177       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 178       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 179       ptr->hosts[server_key].write_buffer_offset= 0;
 180     }
 181   }
 182
 183   if (with_flush)
 184   {
 185     memcached_return rc;
 186     if (io_flush(ptr, server_key, &rc) == -1)
 187       return -1;
 188   }
 189
 190   return length;
 191 }
 192
 193 memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 194 {
 195   close(ptr->hosts[server_key].fd);
 196
 197   return MEMCACHED_SUCCESS;
 198 }
 199
 200 static ssize_t io_flush(memcached_st *ptr, unsigned int server_key,
 201                                   memcached_return *error)
 202 {
 203   size_t sent_length;
 204   size_t return_length;
 205   char *write_ptr= ptr->hosts[server_key].write_buffer;
 206   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 207
 208   *error= MEMCACHED_SUCCESS;
 209
 210   if (ptr->hosts[server_key].write_buffer_offset == 0)
 211     return 0;
 212
 213   return_length= 0;
 214   while (write_length)
 215   {
 216     sent_length= 0;
 217     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 218     {
 219       sent_length= sendto(ptr->hosts[server_key].fd,
 220                           write_ptr, write_length, 0,
 221                           (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr,
 222                           sizeof(struct sockaddr));
 223     }
 224     else
 225     {
 226       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 227                                        write_length)) == -1)
 228       {
 229         switch (errno)
 230         {
 231         case ENOBUFS:
 232           continue;
 233         case EAGAIN:
 234           {
 235             memcached_return rc;
 236             rc= io_wait(ptr, server_key, MEM_WRITE);
 237
 238             if (rc == MEMCACHED_SUCCESS)
 239               continue;
 240
 241             memcached_quit_server(ptr, server_key, 1);
 242             return -1;
 243           }
 244         default:
 245           memcached_quit_server(ptr, server_key, 1);
 246           ptr->cached_errno= errno;
 247           *error= MEMCACHED_ERRNO;
 248           return -1;
 249         }
 250       }
 251     }
 252
 253     write_ptr+= sent_length;
 254     write_length-= sent_length;
 255     return_length+= sent_length;
 256   }
 257
 258   WATCHPOINT_ASSERT(write_length == 0);
 259   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 260   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 261   ptr->hosts[server_key].write_buffer_offset= 0;
 262
 263   return return_length;
 264 }
 265
 266 /*
 267   Eventually we will just kill off the server with the problem.
 268 */
 269 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 270 {
 271   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 272   ptr->hosts[server_key].write_buffer_offset= 0;
 273   memcached_quit(ptr);
 274 }