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_server_st *ptr, memcached_return *error);
  16
  17 static memcached_return io_wait(memcached_server_st *ptr,
  18                                 memc_read_or_write read_or_write)
  19 {
  20   struct pollfd fds[1];
  21   short flags= 0;
  22   int error;
  23
  24   if (read_or_write == MEM_WRITE) /* write */
  25     flags= POLLOUT |  POLLERR;
  26   else
  27     flags= POLLIN | POLLERR;
  28
  29   memset(&fds, 0, sizeof(struct pollfd));
  30   fds[0].fd= ptr->fd;
  31   fds[0].events= flags;
  32
  33   error= poll(fds, 1, ptr->root->poll_timeout);
  34
  35   if (error == 1)
  36     return MEMCACHED_SUCCESS;
  37   else if (error == 0)
  38   {
  39     return MEMCACHED_TIMEOUT;
  40   }
  41
  42   /* Imposssible for anything other then -1 */
  43   WATCHPOINT_ASSERT(error == -1);
  44   memcached_quit_server(ptr, 1);
  45
  46   return MEMCACHED_FAILURE;
  47
  48 }
  49
  50 #ifdef UNUSED
  51 void memcached_io_preread(memcached_st *ptr)
  52 {
  53   unsigned int x;
  54
  55   return;
  56
  57   for (x= 0; x < ptr->number_of_hosts; x++)
  58   {
  59     if (memcached_server_response_count(ptr, x) &&
  60         ptr->hosts[x].read_data_length < MEMCACHED_MAX_BUFFER )
  61     {
  62       size_t data_read;
  63
  64       data_read= read(ptr->hosts[x].fd,
  65                       ptr->hosts[x].read_ptr + ptr->hosts[x].read_data_length,
  66                       MEMCACHED_MAX_BUFFER - ptr->hosts[x].read_data_length);
  67       if (data_read == -1)
  68         continue;
  69
  70       ptr->hosts[x].read_buffer_length+= data_read;
  71       ptr->hosts[x].read_data_length+= data_read;
  72     }
  73   }
  74 }
  75 #endif
  76
  77 ssize_t memcached_io_read(memcached_server_st *ptr,
  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->read_buffer_length)
  88     {
  89       size_t data_read;
  90
  91       while (1)
  92       {
  93         data_read= read(ptr->fd,
  94                         ptr->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, MEM_READ);
 105
 106               if (rc == MEMCACHED_SUCCESS)
 107                 continue;
 108
 109               memcached_quit_server(ptr, 1);
 110               return -1;
 111             }
 112           default:
 113             {
 114               memcached_quit_server(ptr, 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->read_data_length= data_read;
 132       ptr->read_buffer_length= data_read;
 133       ptr->read_ptr= ptr->read_buffer;
 134     }
 135
 136     if (length > 1)
 137     {
 138       size_t difference;
 139
 140       difference= (length > ptr->read_buffer_length) ? ptr->read_buffer_length : length;
 141
 142       memcpy(buffer_ptr, ptr->read_ptr, difference);
 143       length -= difference;
 144       ptr->read_ptr+= difference;
 145       ptr->read_buffer_length-= difference;
 146       buffer_ptr+= difference;
 147     }
 148     else
 149     {
 150       *buffer_ptr= *ptr->read_ptr;
 151       length--;
 152       ptr->read_ptr++;
 153       ptr->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_server_st *ptr,
 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     ptr->write_buffer[ptr->write_buffer_offset]= buffer[x];
 172     ptr->write_buffer_offset++;
 173     WATCHPOINT_ASSERT(ptr->write_buffer_offset <= MEMCACHED_MAX_BUFFER);
 174
 175     if (ptr->write_buffer_offset == MEMCACHED_MAX_BUFFER)
 176     {
 177       memcached_return rc;
 178       ssize_t sent_length;
 179
 180       sent_length= io_flush(ptr, &rc);
 181       if (sent_length == -1)
 182         return -1;
 183
 184       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 185     }
 186   }
 187
 188   if (with_flush)
 189   {
 190     memcached_return rc;
 191     if (io_flush(ptr, &rc) == -1)
 192       return -1;
 193   }
 194
 195   return length;
 196 }
 197
 198 memcached_return memcached_io_close(memcached_server_st *ptr)
 199 {
 200   close(ptr->fd);
 201
 202   return MEMCACHED_SUCCESS;
 203 }
 204
 205 static ssize_t io_flush(memcached_server_st *ptr,
 206                                   memcached_return *error)
 207 {
 208   size_t sent_length;
 209   size_t return_length;
 210   char *local_write_ptr= ptr->write_buffer;
 211   size_t write_length= ptr->write_buffer_offset;
 212
 213   *error= MEMCACHED_SUCCESS;
 214
 215   if (ptr->write_buffer_offset == 0)
 216     return 0;
 217
 218   /* Looking for memory overflows */
 219   if (write_length == MEMCACHED_MAX_BUFFER)
 220     WATCHPOINT_ASSERT(ptr->write_buffer == local_write_ptr);
 221   WATCHPOINT_ASSERT((ptr->write_buffer + MEMCACHED_MAX_BUFFER) >= (local_write_ptr + write_length));
 222   return_length= 0;
 223   while (write_length)
 224   {
 225     sent_length= 0;
 226     if (ptr->type == MEMCACHED_CONNECTION_UDP)
 227     {
 228       sent_length= sendto(ptr->fd, local_write_ptr, write_length, 0,
 229                           (struct sockaddr *)&ptr->address_info->ai_addr,
 230                           sizeof(struct sockaddr));
 231     }
 232     else
 233     {
 234       if ((ssize_t)(sent_length= write(ptr->fd, local_write_ptr,
 235                                        write_length)) == -1)
 236       {
 237         switch (errno)
 238         {
 239         case ENOBUFS:
 240           continue;
 241         case EAGAIN:
 242           {
 243             memcached_return rc;
 244             rc= io_wait(ptr, MEM_WRITE);
 245
 246             if (rc == MEMCACHED_SUCCESS)
 247               continue;
 248
 249             memcached_quit_server(ptr, 1);
 250             return -1;
 251           }
 252         default:
 253           memcached_quit_server(ptr, 1);
 254           ptr->cached_errno= errno;
 255           *error= MEMCACHED_ERRNO;
 256           return -1;
 257         }
 258       }
 259     }
 260
 261     local_write_ptr+= sent_length;
 262     write_length-= sent_length;
 263     return_length+= sent_length;
 264   }
 265
 266   WATCHPOINT_ASSERT(write_length == 0);
 267   WATCHPOINT_ASSERT(return_length == ptr->write_buffer_offset);
 268   ptr->write_buffer_offset= 0;
 269
 270   return return_length;
 271 }
 272
 273 /*
 274   Eventually we will just kill off the server with the problem.
 275 */
 276 void memcached_io_reset(memcached_server_st *ptr)
 277 {
 278   ptr->write_buffer_offset= 0;
 279   memcached_quit_server(ptr, 0);
 280 }