src/os/unix/ngx_aio_read.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  */
   5
   6
   7 #include <ngx_config.h>
   8 #include <ngx_core.h>
   9 #include <ngx_event.h>
  10 #include <ngx_aio.h>
  11
  12 #if (NGX_HAVE_KQUEUE)
  13 #include <ngx_kqueue_module.h>
  14 #endif
  15
  16
  17 /*
  18  * the ready data requires 3 syscalls:
  19  *     aio_write(), aio_error(), aio_return()
  20  * the non-ready data requires 4 (kqueue) or 5 syscalls:
  21  *     aio_write(), aio_error(), notifiction, aio_error(), aio_return()
  22  *                               timeout, aio_cancel(), aio_error()
  23  */
  24
  25 ssize_t ngx_aio_read(ngx_connection_t *c, u_char *buf, size_t size)
  26 {
  27     int           n;
  28     ngx_event_t  *rev;
  29
  30     rev = c->read;
  31
  32     if (!rev->ready) {
  33         ngx_log_error(NGX_LOG_ALERT, c->log, 0, "second aio post");
  34         return NGX_AGAIN;
  35     }
  36
  37     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
  38                    "rev->complete: %d", rev->complete);
  39     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
  40                    "aio size: %d", size);
  41
  42     if (!rev->complete) {
  43         ngx_memzero(&rev->aiocb, sizeof(struct aiocb));
  44
  45         rev->aiocb.aio_fildes = c->fd;
  46         rev->aiocb.aio_buf = buf;
  47         rev->aiocb.aio_nbytes = size;
  48
  49 #if (NGX_HAVE_KQUEUE)
  50         rev->aiocb.aio_sigevent.sigev_notify_kqueue = ngx_kqueue;
  51         rev->aiocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
  52         rev->aiocb.aio_sigevent.sigev_value.sigval_ptr = rev;
  53 #endif
  54
  55         if (aio_read(&rev->aiocb) == -1) {
  56             ngx_log_error(NGX_LOG_CRIT, rev->log, ngx_errno,
  57                           "aio_read() failed");
  58             rev->error = 1;
  59             return NGX_ERROR;
  60         }
  61
  62         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
  63                        "aio_read: #%d OK", c->fd);
  64
  65         rev->active = 1;
  66         rev->ready = 0;
  67     }
  68
  69     rev->complete = 0;
  70
  71     n = aio_error(&rev->aiocb);
  72     if (n == -1) {
  73         ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "aio_error() failed");
  74         rev->error = 1;
  75         return NGX_ERROR;
  76     }
  77
  78     if (n != 0) {
  79         if (n == NGX_EINPROGRESS) {
  80             if (rev->ready) {
  81                 ngx_log_error(NGX_LOG_ALERT, c->log, n,
  82                               "aio_read() still in progress");
  83                 rev->ready = 0;
  84             }
  85             return NGX_AGAIN;
  86         }
  87
  88         ngx_log_error(NGX_LOG_CRIT, c->log, n, "aio_read() failed");
  89         rev->error = 1;
  90         rev->ready = 0;
  91         return NGX_ERROR;
  92     }
  93
  94     n = aio_return(&rev->aiocb);
  95     if (n == -1) {
  96         ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno,
  97                       "aio_return() failed");
  98
  99         rev->error = 1;
 100         rev->ready = 0;
 101         return NGX_ERROR;
 102     }
 103
 104     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, rev->log, 0,
 105                    "aio_read: #%d %d", c->fd, n);
 106
 107     if (n == 0) {
 108         rev->eof = 1;
 109         rev->ready = 0;
 110     } else {
 111         rev->ready = 1;
 112     }
 113
 114     rev->active = 0;
 115
 116     return n;
 117 }