1 
2 /*
3  * Copyright (C) Igor Sysoev
4  * Copyright (C) Nginx, Inc.
5  */
6 
7 
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 #include <ngx_event.h>
11 
12 
13 /*
14  * FreeBSD file AIO features and quirks:
15  *
16  *    if an asked data are already in VM cache, then aio_error() returns 0,
17  *    and the data are already copied in buffer;
18  *
19  *    aio_read() preread in VM cache as minimum 16K (probably BKVASIZE);
20  *    the first AIO preload may be up to 128K;
21  *
22  *    aio_read/aio_error() may return EINPROGRESS for just written data;
23  *
24  *    kqueue EVFILT_AIO filter is level triggered only: an event repeats
25  *    until aio_return() will be called;
26  *
27  *    aio_cancel() cannot cancel file AIO: it returns AIO_NOTCANCELED always.
28  */
29 
30 
31 extern int  ngx_kqueue;
32 
33 
34 static ssize_t ngx_file_aio_result(ngx_file_t *file, ngx_event_aio_t *aio,
35     ngx_event_t *ev);
36 static void ngx_file_aio_event_handler(ngx_event_t *ev);
37 
38 
39 ngx_int_t
ngx_file_aio_init(ngx_file_t * file,ngx_pool_t * pool)40 ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool)
41 {
42     ngx_event_aio_t  *aio;
43 
44     aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t));
45     if (aio == NULL) {
46         return NGX_ERROR;
47     }
48 
49     aio->file = file;
50     aio->fd = file->fd;
51     aio->event.data = aio;
52     aio->event.ready = 1;
53     aio->event.log = file->log;
54 
55     file->aio = aio;
56 
57     return NGX_OK;
58 }
59 
60 
61 ssize_t
ngx_file_aio_read(ngx_file_t * file,u_char * buf,size_t size,off_t offset,ngx_pool_t * pool)62 ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
63     ngx_pool_t *pool)
64 {
65     int               n;
66     ngx_event_t      *ev;
67     ngx_event_aio_t  *aio;
68 
69     if (!ngx_file_aio) {
70         return ngx_read_file(file, buf, size, offset);
71     }
72 
73     if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) {
74         return NGX_ERROR;
75     }
76 
77     aio = file->aio;
78     ev = &aio->event;
79 
80     if (!ev->ready) {
81         ngx_log_error(NGX_LOG_ALERT, file->log, 0,
82                       "second aio post for \"%V\"", &file->name);
83         return NGX_AGAIN;
84     }
85 
86     ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0,
87                    "aio complete:%d @%O:%uz %V",
88                    ev->complete, offset, size, &file->name);
89 
90     if (ev->complete) {
91         ev->complete = 0;
92         ngx_set_errno(aio->err);
93 
94         if (aio->err == 0) {
95             return aio->nbytes;
96         }
97 
98         ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno,
99                       "aio read \"%s\" failed", file->name.data);
100 
101         return NGX_ERROR;
102     }
103 
104     ngx_memzero(&aio->aiocb, sizeof(struct aiocb));
105 
106     aio->aiocb.aio_fildes = file->fd;
107     aio->aiocb.aio_offset = offset;
108     aio->aiocb.aio_buf = buf;
109     aio->aiocb.aio_nbytes = size;
110 #if (NGX_HAVE_KQUEUE) || (NGX_HAVE_FSTACK)
111     aio->aiocb.aio_sigevent.sigev_notify_kqueue = ngx_kqueue;
112     aio->aiocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
113     aio->aiocb.aio_sigevent.sigev_value.sival_ptr = ev;
114 #endif
115     ev->handler = ngx_file_aio_event_handler;
116 
117     n = aio_read(&aio->aiocb);
118 
119     if (n == -1) {
120         n = ngx_errno;
121 
122         if (n == NGX_EAGAIN) {
123             return ngx_read_file(file, buf, size, offset);
124         }
125 
126         ngx_log_error(NGX_LOG_CRIT, file->log, n,
127                       "aio_read(\"%V\") failed", &file->name);
128 
129         if (n == NGX_ENOSYS) {
130             ngx_file_aio = 0;
131             return ngx_read_file(file, buf, size, offset);
132         }
133 
134         return NGX_ERROR;
135     }
136 
137     ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0,
138                    "aio_read: fd:%d %d", file->fd, n);
139 
140     ev->active = 1;
141     ev->ready = 0;
142     ev->complete = 0;
143 
144     return ngx_file_aio_result(aio->file, aio, ev);
145 }
146 
147 
148 static ssize_t
ngx_file_aio_result(ngx_file_t * file,ngx_event_aio_t * aio,ngx_event_t * ev)149 ngx_file_aio_result(ngx_file_t *file, ngx_event_aio_t *aio, ngx_event_t *ev)
150 {
151     int        n;
152     ngx_err_t  err;
153 
154     n = aio_error(&aio->aiocb);
155 
156     ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0,
157                    "aio_error: fd:%d %d", file->fd, n);
158 
159     if (n == -1) {
160         err = ngx_errno;
161         aio->err = err;
162 
163         ngx_log_error(NGX_LOG_ALERT, file->log, err,
164                       "aio_error(\"%V\") failed", &file->name);
165         return NGX_ERROR;
166     }
167 
168     if (n == NGX_EINPROGRESS) {
169         if (ev->ready) {
170             ev->ready = 0;
171             ngx_log_error(NGX_LOG_ALERT, file->log, n,
172                           "aio_read(\"%V\") still in progress",
173                           &file->name);
174         }
175 
176         return NGX_AGAIN;
177     }
178 
179     n = aio_return(&aio->aiocb);
180 
181     if (n == -1) {
182         err = ngx_errno;
183         aio->err = err;
184         ev->ready = 1;
185 
186         ngx_log_error(NGX_LOG_CRIT, file->log, err,
187                       "aio_return(\"%V\") failed", &file->name);
188         return NGX_ERROR;
189     }
190 
191     aio->err = 0;
192     aio->nbytes = n;
193     ev->ready = 1;
194     ev->active = 0;
195 
196     ngx_log_debug2(NGX_LOG_DEBUG_CORE, file->log, 0,
197                    "aio_return: fd:%d %d", file->fd, n);
198 
199     return n;
200 }
201 
202 
203 static void
ngx_file_aio_event_handler(ngx_event_t * ev)204 ngx_file_aio_event_handler(ngx_event_t *ev)
205 {
206     ngx_event_aio_t  *aio;
207 
208     aio = ev->data;
209 
210     ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0,
211                    "aio event handler fd:%d %V", aio->fd, &aio->file->name);
212 
213     if (ngx_file_aio_result(aio->file, aio, ev) != NGX_AGAIN) {
214         aio->handler(ev);
215     }
216 }
217