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 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->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->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->my_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->read_buffer_length= data_read;
  76       ptr->read_ptr= ptr->read_buffer;
  77     }
  78
  79     *buffer_ptr= *ptr->read_ptr;
  80     length--;
  81     ptr->read_ptr++;
  82     ptr->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     ptr->write_buffer[ptr->write_buffer_offset]= buffer[x];
  97     ptr->write_buffer_offset++;
  98
  99     if (ptr->write_buffer_offset == MEMCACHED_MAX_BUFFER)
 100     {
 101       size_t sent_length;
 102
 103       sent_length= memcached_io_flush(ptr, server_key);
 104
 105       WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
 106       ptr->write_buffer_offset= 0;
 107     }
 108   }
 109
 110   if (with_flush)
 111   {
 112     if (memcached_io_flush(ptr, server_key) == -1)
 113       return -1;
 114   }
 115
 116   return length;
 117 }
 118
 119 ssize_t memcached_io_flush(memcached_st *ptr, unsigned int server_key)
 120 {
 121   size_t sent_length;
 122   size_t return_length;
 123   char *write_ptr= ptr->write_buffer;
 124   size_t write_length= ptr->write_buffer_offset;
 125   unsigned int loop= 1;
 126
 127   if (ptr->write_buffer_offset == 0)
 128     return 0;
 129
 130   return_length= 0;
 131   while (write_length)
 132   {
 133     if (ptr->flags & MEM_NO_BLOCK)
 134     {
 135       memcached_return rc;
 136
 137       rc= io_wait(ptr, server_key, 1);
 138       if (rc != MEMCACHED_SUCCESS)
 139         return -1;
 140     }
 141
 142     sent_length= 0;
 143     if ((ssize_t)(sent_length= write(ptr->hosts[server_key].fd, write_ptr,
 144                                      write_length)) == -1)
 145     {
 146       switch (errno)
 147       {
 148       case ENOBUFS:
 149       case EAGAIN:
 150         WATCHPOINT;
 151         continue;
 152         if (loop < 100)
 153         {
 154           loop++;
 155           break;
 156         }
 157         /* Yes, we want to fall through */
 158       default:
 159         ptr->my_errno= errno;
 160         return -1;
 161       }
 162     }
 163
 164     write_ptr+= sent_length;
 165     write_length-= sent_length;
 166     return_length+= sent_length;
 167   }
 168
 169   WATCHPOINT_ASSERT(write_length == 0);
 170   WATCHPOINT_ASSERT(return_length == ptr->write_buffer_offset);
 171   ptr->write_buffer_offset= 0;
 172
 173   return return_length;
 174 }
 175
 176 /*
 177   Eventually we will just kill off the server with the problem.
 178 */
 179 void memcached_io_reset(memcached_st *ptr, unsigned int server_key)
 180 {
 181   ptr->write_buffer_offset= 0;
 182   memcached_quit(ptr);
 183 }