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 static int io_wait(memcached_st *ptr, unsigned int server_key, unsigned read_or_write)
  11 {
  12   struct pollfd fds[1];
  13   short flags= 0;
  14
  15   if (read_or_write)
  16     flags= POLLOUT |  POLLERR;
  17   else
  18     flags= POLLIN | POLLERR;
  19
  20   memset(&fds, 0, sizeof(struct pollfd));
  21   fds[0].fd= ptr->hosts[server_key].fd;
  22   fds[0].events= flags;
  23
  24   if (poll(fds, 1, -1) < 0)
  25     return MEMCACHED_FAILURE;
  26
  27   return MEMCACHED_SUCCESS;
  28 }
  29
  30 ssize_t memcached_io_read(memcached_st *ptr, unsigned  int server_key,
  31                           char *buffer, size_t length)
  32 {
  33   char *buffer_ptr;
  34
  35   buffer_ptr= buffer;
  36
  37   while (length)
  38   {
  39     if (!ptr->hosts[server_key].read_buffer_length)
  40     {
  41       size_t data_read;
  42
  43       while (1)
  44       {
  45         if (ptr->flags & MEM_NO_BLOCK)
  46         {
  47           memcached_return rc;
  48
  49           rc= io_wait(ptr, server_key, 0);
  50           if (rc != MEMCACHED_SUCCESS)
  51             return -1;
  52         }
  53
  54         data_read= read(ptr->hosts[server_key].fd,
  55                         ptr->hosts[server_key].read_buffer,
  56                         MEMCACHED_MAX_BUFFER);
  57         if (data_read == -1)
  58         {
  59           switch (errno)
  60           {
  61           case EAGAIN:
  62             break;
  63           default:
  64             {
  65               ptr->cached_errno= errno;
  66               return -1;
  67             }
  68           }
  69         }
  70         else if (data_read)
  71           break;
  72         /* If zero, just keep looping */
  73       }
  74
  75       ptr->hosts[server_key].read_buffer_length= data_read;
  76       ptr->hosts[server_key].read_ptr= ptr->hosts[server_key].read_buffer;
  77     }
  78
  79     *buffer_ptr= *ptr->hosts[server_key].read_ptr;
  80     length--;
  81     ptr->hosts[server_key].read_ptr++;
  82     ptr->hosts[server_key].read_buffer_length--;
  83     buffer_ptr++;
  84   }
  85
  86   return (size_t)(buffer_ptr - buffer);
  87 }
  88
  89 ssize_t memcached_io_write(memcached_st *ptr, unsigned int server_key,
  90                         char *buffer, size_t length, char with_flush)
  91 {
  92   unsigned long long x;
  93
  94   for (x= 0; x < length; x++)
  95   {
  96     if (ptr->hosts[server_key].write_ptr == 0)
  97       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
  98     WATCHPOINT_ASSERT(ptr->hosts[server_key].write_ptr);
  99     *ptr->hosts[server_key].write_ptr= buffer[x];
 100     ptr->hosts[server_key].write_ptr++;
 101     ptr->hosts[server_key].write_buffer_offset++;
 102
 103     if (ptr->hosts[server_key].write_buffer_offset == MEMCACHED_MAX_BUFFER)
 104     {
 105       size_t sent_length;
 106
 107       sent_length= memcached_io_flush(ptr, server_key);
 108
 109       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 110       ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 111       ptr->hosts[server_key].write_buffer_offset= 0;
 112     }
 113   }
 114
 115   if (with_flush)
 116   {
 117     if (memcached_io_flush(ptr, server_key) == -1)
 118       return -1;
 119   }
 120
 121   return length;
 122 }
 123
 124 ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key)
 125 {
 126   size_t sent_length;
 127   size_t return_length;
 128   char *write_ptr= ptr->hosts[server_key].write_buffer;
 129   size_t write_length= ptr->hosts[server_key].write_buffer_offset;
 130   unsigned int loop= 1;
 131
 132   if (ptr->hosts[server_key].write_buffer_offset == 0)
 133     return 0;
 134
 135   return_length= 0;
 136   while (write_length)
 137   {
 138     if (ptr->flags & MEM_NO_BLOCK)
 139     {
 140       memcached_return rc;
 141
 142       rc= io_wait(ptr, server_key, 1);
 143       if (rc != MEMCACHED_SUCCESS)
 144         return -1;
 145     }
 146
 147     sent_length= 0;
 148     if (ptr->hosts[server_key].type == MEMCACHED_CONNECTION_UDP)
 149     {
 150       sent_length= sendto(ptr->hosts[server_key].fd,
 151                           write_ptr, write_length, 0,
 152                           (struct sockaddr *)&ptr->hosts[server_key].servAddr,
 153                           sizeof(struct sockaddr));
 154     }
 155     else
 156     {
 157       if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 158                                        write_length)) == -1)
 159       {
 160         switch (errno)
 161         {
 162         case ENOBUFS:
 163         case EAGAIN:
 164           WATCHPOINT;
 165           continue;
 166           if (loop < 100)
 167           {
 168             loop++;
 169             break;
 170           }
 171           /* Yes, we want to fall through */
 172         default:
 173           ptr->cached_errno= errno;
 174           return -1;
 175         }
 176       }
 177     }
 178
 179     write_ptr+= sent_length;
 180     write_length-= sent_length;
 181     return_length+= sent_length;
 182   }
 183
 184   WATCHPOINT_ASSERT(write_length == 0);
 185   WATCHPOINT_ASSERT(return_length == ptr->hosts[server_key].write_buffer_offset);
 186   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 187   ptr->hosts[server_key].write_buffer_offset= 0;
 188
 189   return return_length;
 190 }
 191
 192 /*
 193   Eventually we will just kill off the server with the problem.
 194 */
 195 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 196 {
 197   ptr->hosts[server_key].write_ptr= ptr->hosts[server_key].write_buffer;
 198   ptr->hosts[server_key].write_buffer_offset= 0;
 199   memcached_quit(ptr);
 200 }