git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/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       ssize_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 > 0)
  97           break;
  98         else if (data_read == -1)
  99         {
 100           ptr->cached_errno= errno;
 101           switch (errno)
 102           {
 103           case EAGAIN:
 104             {
 105               memcached_return rc;
 106
 107               rc= io_wait(ptr, MEM_READ);
 108
 109               if (rc == MEMCACHED_SUCCESS)
 110                 continue;
 111             }
 112           /* fall trough */
 113           default:
 114             {
 115               memcached_quit_server(ptr, 1);
 116               return -1;
 117             }
 118           }
 119         }
 120         else
 121         {
 122           found_eof= 1;
 123           break;
 124         }
 125       }
 126
 127       ptr->read_data_length= data_read;
 128       ptr->read_buffer_length= data_read;
 129       ptr->read_ptr= ptr->read_buffer;
 130     }
 131
 132     if (length > 1)
 133     {
 134       size_t difference;
 135
 136       difference= (length > ptr->read_buffer_length) ? ptr->read_buffer_length : length;
 137
 138       memcpy(buffer_ptr, ptr->read_ptr, difference);
 139       length -= difference;
 140       ptr->read_ptr+= difference;
 141       ptr->read_buffer_length-= difference;
 142       buffer_ptr+= difference;
 143     }
 144     else
 145     {
 146       *buffer_ptr= *ptr->read_ptr;
 147       ptr->read_ptr++;
 148       ptr->read_buffer_length--;
 149       buffer_ptr++;
 150       break;
 151     }
 152
 153     if (found_eof)
 154       break;
 155   }
 156
 157   return (size_t)(buffer_ptr - buffer);
 158 }
 159
 160 ssize_t memcached_io_write(memcached_server_st *ptr,
 161                            char *buffer, size_t length, char with_flush)
 162 {
 163   size_t original_length;
 164   char* buffer_ptr;
 165
 166   original_length= length;
 167   buffer_ptr= buffer;
 168
 169   while (length)
 170   {
 171     char *write_ptr;
 172     size_t should_write;
 173
 174     should_write= MEMCACHED_MAX_BUFFER - ptr->write_buffer_offset;
 175     write_ptr= ptr->write_buffer + ptr->write_buffer_offset;
 176
 177     should_write= (should_write < length) ? should_write : length;
 178
 179     memcpy(write_ptr, buffer_ptr, should_write);
 180     ptr->write_buffer_offset+= should_write;
 181     buffer_ptr+= should_write;
 182     length-= should_write;
 183
 184     if (ptr->write_buffer_offset == MEMCACHED_MAX_BUFFER)
 185     {
 186       memcached_return rc;
 187       ssize_t sent_length;
 188
 189       sent_length= io_flush(ptr, &rc);
 190       if (sent_length == -1)
 191         return -1;
 192
 193       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 194     }
 195   }
 196
 197   if (with_flush)
 198   {
 199     memcached_return rc;
 200     if (io_flush(ptr, &rc) == -1)
 201       return -1;
 202   }
 203
 204   return original_length;
 205 }
 206
 207 memcached_return memcached_io_close(memcached_server_st *ptr)
 208 {
 209   close(ptr->fd);
 210
 211   return MEMCACHED_SUCCESS;
 212 }
 213
 214 static ssize_t io_flush(memcached_server_st *ptr,
 215                         memcached_return *error)
 216 {
 217   size_t sent_length;
 218   size_t return_length;
 219   char *local_write_ptr= ptr->write_buffer;
 220   size_t write_length= ptr->write_buffer_offset;
 221
 222   *error= MEMCACHED_SUCCESS;
 223
 224   if (ptr->write_buffer_offset == 0)
 225     return 0;
 226
 227   /* Looking for memory overflows */
 228   if (write_length == MEMCACHED_MAX_BUFFER)
 229     WATCHPOINT_ASSERT(ptr->write_buffer == local_write_ptr);
 230   WATCHPOINT_ASSERT((ptr->write_buffer + MEMCACHED_MAX_BUFFER) >= (local_write_ptr + write_length));
 231
 232   return_length= 0;
 233   while (write_length)
 234   {
 235     WATCHPOINT_ASSERT(write_length > 0);
 236     sent_length= 0;
 237     if (ptr->type == MEMCACHED_CONNECTION_UDP)
 238     {
 239       struct addrinfo *ai;
 240
 241       ai= ptr->address_info;
 242
 243       /* Crappy test code */
 244       char buffer[HUGE_STRING_LEN + 8];
 245       memset(buffer, 0, HUGE_STRING_LEN + 8);
 246       memcpy (buffer+8, local_write_ptr, write_length);
 247       buffer[0]= 0;
 248       buffer[1]= 0;
 249       buffer[2]= 0;
 250       buffer[3]= 0;
 251       buffer[4]= 0;
 252       buffer[5]= 1;
 253       buffer[6]= 0;
 254       buffer[7]= 0;
 255       sent_length= sendto(ptr->fd, buffer, write_length + 8, 0,
 256                           (struct sockaddr *)ai->ai_addr,
 257                           ai->ai_addrlen);
 258       if (sent_length == -1)
 259       {
 260         WATCHPOINT_ERRNO(errno);
 261         WATCHPOINT_ASSERT(0);
 262       }
 263       sent_length-= 8; /* We remove the header */
 264     }
 265     else
 266     {
 267       if ((ssize_t)(sent_length= write(ptr->fd, local_write_ptr,
 268                                        write_length)) == -1)
 269       {
 270         switch (errno)
 271         {
 272         case ENOBUFS:
 273           continue;
 274         case EAGAIN:
 275           {
 276             memcached_return rc;
 277             rc= io_wait(ptr, MEM_WRITE);
 278
 279             if (rc == MEMCACHED_SUCCESS)
 280               continue;
 281
 282             memcached_quit_server(ptr, 1);
 283             return -1;
 284           }
 285         default:
 286           memcached_quit_server(ptr, 1);
 287           ptr->cached_errno= errno;
 288           *error= MEMCACHED_ERRNO;
 289           return -1;
 290         }
 291       }
 292     }
 293
 294     local_write_ptr+= sent_length;
 295     write_length-= sent_length;
 296     return_length+= sent_length;
 297   }
 298
 299   WATCHPOINT_ASSERT(write_length == 0);
 300   WATCHPOINT_ASSERT(return_length == ptr->write_buffer_offset);
 301   ptr->write_buffer_offset= 0;
 302
 303   return return_length;
 304 }
 305
 306 /*
 307   Eventually we will just kill off the server with the problem.
 308 */
 309 void memcached_io_reset(memcached_server_st *ptr)
 310 {
 311   memcached_quit_server(ptr, 0);
 312 }