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view src/os/unix/ngx_solaris_sendfilev_chain.c @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | 646985c55393 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #if (NGX_TEST_BUILD_SOLARIS_SENDFILEV) /* Solaris declarations */ typedef struct sendfilevec { int sfv_fd; u_int sfv_flag; off_t sfv_off; size_t sfv_len; } sendfilevec_t; #define SFV_FD_SELF -2 static ssize_t sendfilev(int fd, const struct sendfilevec *vec, int sfvcnt, size_t *xferred) { return -1; } ngx_chain_t *ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit); #endif #define NGX_SENDFILEVECS NGX_IOVS_PREALLOCATE ngx_chain_t * ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { int fd; u_char *prev; off_t size, send, prev_send, aligned, fprev; size_t sent; ssize_t n; ngx_int_t eintr; ngx_err_t err; ngx_buf_t *file; ngx_uint_t nsfv; sendfilevec_t *sfv, sfvs[NGX_SENDFILEVECS]; ngx_event_t *wev; ngx_chain_t *cl; wev = c->write; if (!wev->ready) { return in; } if (!c->sendfile) { return ngx_writev_chain(c, in, limit); } /* the maximum limit size is the maximum size_t value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) { limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize; } send = 0; for ( ;; ) { fd = SFV_FD_SELF; prev = NULL; fprev = 0; file = NULL; sfv = NULL; eintr = 0; sent = 0; prev_send = send; nsfv = 0; /* create the sendfilevec and coalesce the neighbouring bufs */ for (cl = in; cl && send < limit; cl = cl->next) { if (ngx_buf_special(cl->buf)) { continue; } if (ngx_buf_in_memory_only(cl->buf)) { fd = SFV_FD_SELF; size = cl->buf->last - cl->buf->pos; if (send + size > limit) { size = limit - send; } if (prev == cl->buf->pos) { sfv->sfv_len += (size_t) size; } else { if (nsfv == NGX_SENDFILEVECS) { break; } sfv = &sfvs[nsfv++]; sfv->sfv_fd = SFV_FD_SELF; sfv->sfv_flag = 0; sfv->sfv_off = (off_t) (uintptr_t) cl->buf->pos; sfv->sfv_len = (size_t) size; } prev = cl->buf->pos + (size_t) size; send += size; } else { prev = NULL; size = cl->buf->file_last - cl->buf->file_pos; if (send + size > limit) { size = limit - send; aligned = (cl->buf->file_pos + size + ngx_pagesize - 1) & ~((off_t) ngx_pagesize - 1); if (aligned <= cl->buf->file_last) { size = aligned - cl->buf->file_pos; } } if (fd == cl->buf->file->fd && fprev == cl->buf->file_pos) { sfv->sfv_len += (size_t) size; } else { if (nsfv == NGX_SENDFILEVECS) { break; } sfv = &sfvs[nsfv++]; fd = cl->buf->file->fd; sfv->sfv_fd = fd; sfv->sfv_flag = 0; sfv->sfv_off = cl->buf->file_pos; sfv->sfv_len = (size_t) size; } file = cl->buf; fprev = cl->buf->file_pos + size; send += size; } } n = sendfilev(c->fd, sfvs, nsfv, &sent); if (n == -1) { err = ngx_errno; switch (err) { case NGX_EAGAIN: break; case NGX_EINTR: eintr = 1; break; default: wev->error = 1; ngx_connection_error(c, err, "sendfilev() failed"); return NGX_CHAIN_ERROR; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, err, "sendfilev() sent only %uz bytes", sent); } else if (n == 0 && sent == 0) { /* * sendfilev() is documented to return -1 with errno * set to EINVAL if svf_len is greater than the file size, * but at least Solaris 11 returns 0 instead */ if (file) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "sendfilev() reported that \"%s\" was truncated at %O", file->file->name.data, file->file_pos); } else { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "sendfilev() returned 0 with memory buffers"); } return NGX_CHAIN_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "sendfilev: %z %z", n, sent); c->sent += sent; in = ngx_chain_update_sent(in, sent); if (eintr) { send = prev_send + sent; continue; } if (send - prev_send != (off_t) sent) { wev->ready = 0; return in; } if (send >= limit || in == NULL) { return in; } } }