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 (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     uint8_t found_eof= 0;
  87     if (!ptr->hosts[server_key].read_buffer_length)
  88     {
  89       size_t data_read;
  90
  91       while (1)
  92       {
  93         data_read= read(ptr->hosts[server_key].fd,
  94                         ptr->hosts[server_key].read_buffer,
  95                         MEMCACHED_MAX_BUFFER);
  96         if (data_read == -1)
  97         {
  98           switch (errno)
  99           {
 100           case EAGAIN:
 101             {
 102               memcached_return rc;
 103
 104               rc= io_wait(ptr, server_key, MEM_READ);
 105
 106               if (rc == MEMCACHED_SUCCESS)
 107                 continue;
 108
 109               memcached_quit_server(ptr, server_key, 1);
 110               return -1;
 111             }
 112           default:
 113             {
 114               memcached_quit_server(ptr, server_key, 1);
 115               ptr->cached_errno= errno;
 116               return -1;
 117             }
 118           }
 119         }
 120         else if (data_read)
 121           break;
 122         /* If zero, just keep looping unless testing, then assert() */
 123         else
 124         {
 125           WATCHPOINT_ASSERT(0);
 126           found_eof= 1;
 127           break;
 128         }
 129       }
 130
 131       ptr->hosts[server_key].read_data_length= data_read;
 132       ptr->hosts[server_key].read_buffer_length= data_read;
 133       ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
 134     }
 135
 136     if (length > 1)
 137     {
 138       size_t difference;
 139
 140       difference= (length > ptr->hosts[server_key].read_buffer_length) ? ptr->hosts[server_key].read_buffer_length : length;
 141
 142       memcpy(buffer_ptr, ptr->hosts[server_key].read_ptr, difference);
 143       length -= difference;
 144       ptr->hosts[server_key].read_ptr+= difference;
 145       ptr->hosts[server_key].read_buffer_length-= difference;
 146       buffer_ptr+= difference;
 147     }
 148     else
 149     {
 150       *buffer_ptr= *ptr->hosts[server_key].read_ptr;
 151       length--;
 152       ptr->hosts[server_key].read_ptr++;
 153       ptr->hosts[server_key].read_buffer_length--;
 154       buffer_ptr++;
 155     }
 156
 157     if (found_eof)
 158       break;
 159   }
 160
 161   return (size_t)(buffer_ptr - buffer);
 162 }
 163
 164 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
 165                         char *buffer, size_t length, char with_flush)
 166 {
 167   unsigned long long x;
 168
 169   for (x= 0; x < length; x++)
 170   {
 171     if (ptr->hosts[server_key].write_ptr == 0)
 172       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 173     WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
 174     *ptr->hosts[server_key].write_ptr= buffer[x];
 175     ptr->hosts[server_key].write_ptr++;
 176     ptr->hosts[server_key].write_buffer_offset++;
 177
 178     if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
 179     {
 180       memcached_return rc;
 181       size_t sent_length;
 182
 183       sent_length= io_flush(ptr, server_key, &rc);
 184       if (sent_length == -1)
 185         return -1;
 186
 187       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 188       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 189       ptr->hosts[server_key].write_buffer_offset= 0;
 190     }
 191   }
 192
 193   if (with_flush)
 194   {
 195     memcached_return rc;
 196     if (io_flush(ptr, server_key, &rc) == -1)
 197       return -1;
 198   }
 199
 200   return length;
 201 }
 202
 203 memcached_return memcached_io_close(memcached_st *ptr, unsigned int server_key)
 204 {
 205   close(ptr->hosts[server_key].fd);
 206
 207   return MEMCACHED_SUCCESS;
 208 }
 209
 210 static ssize_t io_flush(memcached_st *ptr, unsigned int server_key,
 211                                   memcached_return *error)
 212 {
 213   size_t sent_length;
 214   size_t return_length;
 215   char *write_ptr= ptr->hosts[server_key].write_buffer;
 216   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 217
 218   *error= MEMCACHED_SUCCESS;
 219
 220   if (ptr->hosts[server_key].write_buffer_offset == 0)
 221     return 0;
 222
 223   return_length= 0;
 224   while (write_length)
 225   {
 226     sent_length= 0;
 227     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 228     {
 229       sent_length= sendto(ptr->hosts[server_key].fd,
 230                           write_ptr, write_length, 0,
 231                           (struct sockaddr *)&ptr->hosts[server_key].address_info->ai_addr,
 232                           sizeof(struct sockaddr));
 233     }
 234     else
 235     {
 236       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 237                                        write_length)) == -1)
 238       {
 239         switch (errno)
 240         {
 241         case ENOBUFS:
 242           continue;
 243         case EAGAIN:
 244           {
 245             memcached_return rc;
 246             rc= io_wait(ptr, server_key, MEM_WRITE);
 247
 248             if (rc == MEMCACHED_SUCCESS)
 249               continue;
 250
 251             memcached_quit_server(ptr, server_key, 1);
 252             return -1;
 253           }
 254         default:
 255           memcached_quit_server(ptr, server_key, 1);
 256           ptr->cached_errno= errno;
 257           *error= MEMCACHED_ERRNO;
 258           return -1;
 259         }
 260       }
 261     }
 262
 263     write_ptr+= sent_length;
 264     write_length-= sent_length;
 265     return_length+= sent_length;
 266   }
 267
 268   WATCHPOINT_ASSERT(write_length == 0);
 269   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 270   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 271   ptr->hosts[server_key].write_buffer_offset= 0;
 272
 273   return return_length;
 274 }
 275
 276 /*
 277   Eventually we will just kill off the server with the problem.
 278 */
 279 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 280 {
 281   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 282   ptr->hosts[server_key].write_buffer_offset= 0;
 283   memcached_quit(ptr);
 284 }