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
13ngx_chain_t *
14ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
15{
16    ssize_t        n, sent;
17    off_t          send, prev_send;
18    ngx_chain_t   *cl;
19    ngx_event_t   *wev;
20    ngx_iovec_t    vec;
21    struct iovec   iovs[NGX_IOVS_PREALLOCATE];
22
23    wev = c->write;
24
25    if (!wev->ready) {
26        return in;
27    }
28
29#if (NGX_HAVE_KQUEUE)
30
31    if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) {
32        (void) ngx_connection_error(c, wev->kq_errno,
33                               "kevent() reported about an closed connection");
34        wev->error = 1;
35        return NGX_CHAIN_ERROR;
36    }
37
38#endif
39
40    /* the maximum limit size is the maximum size_t value - the page size */
41
42    if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) {
43        limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize;
44    }
45
46    send = 0;
47
48    vec.iovs = iovs;
49    vec.nalloc = NGX_IOVS_PREALLOCATE;
50
51    for ( ;; ) {
52        prev_send = send;
53
54        /* create the iovec and coalesce the neighbouring bufs */
55
56        cl = ngx_output_chain_to_iovec(&vec, in, limit - send, c->log);
57
58        if (cl == NGX_CHAIN_ERROR) {
59            return NGX_CHAIN_ERROR;
60        }
61
62        if (cl && cl->buf->in_file) {
63            ngx_log_error(NGX_LOG_ALERT, c->log, 0,
64                          "file buf in writev "
65                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
66                          cl->buf->temporary,
67                          cl->buf->recycled,
68                          cl->buf->in_file,
69                          cl->buf->start,
70                          cl->buf->pos,
71                          cl->buf->last,
72                          cl->buf->file,
73                          cl->buf->file_pos,
74                          cl->buf->file_last);
75
76            ngx_debug_point();
77
78            return NGX_CHAIN_ERROR;
79        }
80
81        send += vec.size;
82
83        n = ngx_writev(c, &vec);
84
85        if (n == NGX_ERROR) {
86            return NGX_CHAIN_ERROR;
87        }
88
89        sent = (n == NGX_AGAIN) ? 0 : n;
90
91        c->sent += sent;
92
93        in = ngx_chain_update_sent(in, sent);
94
95        if (send - prev_send != sent) {
96            wev->ready = 0;
97            return in;
98        }
99
100        if (send >= limit || in == NULL) {
101            return in;
102        }
103    }
104}
105
106
107ngx_chain_t *
108ngx_output_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *in, size_t limit,
109    ngx_log_t *log)
110{
111    size_t         total, size;
112    u_char        *prev;
113    ngx_uint_t     n;
114    struct iovec  *iov;
115
116    iov = NULL;
117    prev = NULL;
118    total = 0;
119    n = 0;
120
121    for ( /* void */ ; in && total < limit; in = in->next) {
122
123        if (ngx_buf_special(in->buf)) {
124            continue;
125        }
126
127        if (in->buf->in_file) {
128            break;
129        }
130
131        if (!ngx_buf_in_memory(in->buf)) {
132            ngx_log_error(NGX_LOG_ALERT, log, 0,
133                          "bad buf in output chain "
134                          "t:%d r:%d f:%d %p %p-%p %p %O-%O",
135                          in->buf->temporary,
136                          in->buf->recycled,
137                          in->buf->in_file,
138                          in->buf->start,
139                          in->buf->pos,
140                          in->buf->last,
141                          in->buf->file,
142                          in->buf->file_pos,
143                          in->buf->file_last);
144
145            ngx_debug_point();
146
147            return NGX_CHAIN_ERROR;
148        }
149
150        size = in->buf->last - in->buf->pos;
151
152        if (size > limit - total) {
153            size = limit - total;
154        }
155
156        if (prev == in->buf->pos) {
157            iov->iov_len += size;
158
159        } else {
160            if (n == vec->nalloc) {
161                break;
162            }
163
164            iov = &vec->iovs[n++];
165
166            iov->iov_base = (void *) in->buf->pos;
167            iov->iov_len = size;
168        }
169
170        prev = in->buf->pos + size;
171        total += size;
172    }
173
174    vec->count = n;
175    vec->size = total;
176
177    return in;
178}
179
180
181ssize_t
182ngx_writev(ngx_connection_t *c, ngx_iovec_t *vec)
183{
184    ssize_t    n;
185    ngx_err_t  err;
186
187eintr:
188
189    n = writev(c->fd, vec->iovs, vec->count);
190
191    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
192                   "writev: %z of %uz", n, vec->size);
193
194    if (n == -1) {
195        err = ngx_errno;
196
197        switch (err) {
198        case NGX_EAGAIN:
199            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
200                           "writev() not ready");
201            return NGX_AGAIN;
202
203        case NGX_EINTR:
204            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
205                           "writev() was interrupted");
206            goto eintr;
207
208        default:
209            c->write->error = 1;
210            ngx_connection_error(c, err, "writev() failed");
211            return NGX_ERROR;
212        }
213    }
214
215    return n;
216}
217