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
  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 (memcached_server_response_count(ptr, x) &&
  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 unless testing, then assert() */
 122         else
 123           WATCHPOINT_ASSERT(0);
 124       }
 125
 126       ptr->hosts[server_key].read_data_length= data_read;
 127       ptr->hosts[server_key].read_buffer_length= data_read;
 128       ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
 129     }
 130
 131     if (length > 1)
 132     {
 133       size_t difference;
 134
 135       difference= (length > ptr->hosts[server_key].read_buffer_length) ? ptr->hosts[server_key].read_buffer_length : length;
 136
 137       memcpy(buffer_ptr, ptr->hosts[server_key].read_ptr, difference);
 138       length -= difference;
 139       ptr->hosts[server_key].read_ptr+= difference;
 140       ptr->hosts[server_key].read_buffer_length-= difference;
 141       buffer_ptr+= difference;
 142     }
 143     else
 144     {
 145       *buffer_ptr= *ptr->hosts[server_key].read_ptr;
 146       length--;
 147       ptr->hosts[server_key].read_ptr++;
 148       ptr->hosts[server_key].read_buffer_length--;
 149       buffer_ptr++;
 150     }
 151   }
 152
 153   return (size_t)(buffer_ptr - buffer);
 154 }
 155
 156 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
 157                         char *buffer, size_t length, char with_flush)
 158 {
 159   unsigned long long x;
 160
 161   for (x= 0; x < length; x++)
 162   {
 163     if (ptr->hosts[server_key].write_ptr == 0)
 164       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 165     WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
 166     *ptr->hosts[server_key].write_ptr= buffer[x];
 167     ptr->hosts[server_key].write_ptr++;
 168     ptr->hosts[server_key].write_buffer_offset++;
 169
 170     if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
 171     {
 172       memcached_return rc;
 173       size_t sent_length;
 174
 175       sent_length= io_flush(ptr, server_key, &rc);
 176       if (sent_length == -1)
 177         return -1;
 178
 179       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 180       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 181       ptr->hosts[server_key].write_buffer_offset= 0;
 182     }
 183   }
 184
 185   if (with_flush)
 186   {
 187     memcached_return rc;
 188     if (io_flush(ptr, server_key, &rc) == -1)
 189       return -1;
 190   }
 191
 192   return length;
 193 }
 194
 195 memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 196 {
 197   close(ptr->hosts[server_key].fd);
 198
 199   return MEMCACHED_SUCCESS;
 200 }
 201
 202 static ssize_t io_flush(memcached_st *ptr, unsigned int server_key,
 203                                   memcached_return *error)
 204 {
 205   size_t sent_length;
 206   size_t return_length;
 207   char *write_ptr= ptr->hosts[server_key].write_buffer;
 208   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 209
 210   *error= MEMCACHED_SUCCESS;
 211
 212   if (ptr->hosts[server_key].write_buffer_offset == 0)
 213     return 0;
 214
 215   return_length= 0;
 216   while (write_length)
 217   {
 218     sent_length= 0;
 219     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 220     {
 221       sent_length= sendto(ptr->hosts[server_key].fd,
 222                           write_ptr, write_length, 0,
 223                           (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr,
 224                           sizeof(struct sockaddr));
 225     }
 226     else
 227     {
 228       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 229                                        write_length)) == -1)
 230       {
 231         switch (errno)
 232         {
 233         case ENOBUFS:
 234           continue;
 235         case EAGAIN:
 236           {
 237             memcached_return rc;
 238             rc= io_wait(ptr, server_key, MEM_WRITE);
 239
 240             if (rc == MEMCACHED_SUCCESS)
 241               continue;
 242
 243             memcached_quit_server(ptr, server_key, 1);
 244             return -1;
 245           }
 246         default:
 247           memcached_quit_server(ptr, server_key, 1);
 248           ptr->cached_errno= errno;
 249           *error= MEMCACHED_ERRNO;
 250           return -1;
 251         }
 252       }
 253     }
 254
 255     write_ptr+= sent_length;
 256     write_length-= sent_length;
 257     return_length+= sent_length;
 258   }
 259
 260   WATCHPOINT_ASSERT(write_length == 0);
 261   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 262   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 263   ptr->hosts[server_key].write_buffer_offset= 0;
 264
 265   return return_length;
 266 }
 267
 268 /*
 269   Eventually we will just kill off the server with the problem.
 270 */
 271 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 272 {
 273   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 274   ptr->hosts[server_key].write_buffer_offset= 0;
 275   memcached_quit(ptr);
 276 }