Mercurial > hg > nginx
view src/os/unix/ngx_writev_chain.c @ 7851:aa5f8825f24d
Resolver: fixed label types handling in ngx_resolver_copy().
Previously, anything with any of the two high bits set were interpreted
as compression pointers. This is incorrect, as RFC 1035 clearly states
that "The 10 and 01 combinations are reserved for future use". Further,
the 01 combination is actually allocated for EDNS extended label type
(see RFC 2671 and RFC 6891), not really used though.
Fix is to reject unrecognized label types rather than misinterpreting
them as compression pointers.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 25 May 2021 15:17:41 +0300 |
parents | 2c64b69daec5 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> ngx_chain_t * ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { ssize_t n, sent; off_t send, prev_send; ngx_chain_t *cl; ngx_event_t *wev; ngx_iovec_t vec; struct iovec iovs[NGX_IOVS_PREALLOCATE]; wev = c->write; if (!wev->ready) { return in; } #if (NGX_HAVE_KQUEUE) if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) { (void) ngx_connection_error(c, wev->kq_errno, "kevent() reported about an closed connection"); wev->error = 1; return NGX_CHAIN_ERROR; } #endif /* 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; vec.iovs = iovs; vec.nalloc = NGX_IOVS_PREALLOCATE; for ( ;; ) { prev_send = send; /* create the iovec and coalesce the neighbouring bufs */ cl = ngx_output_chain_to_iovec(&vec, in, limit - send, c->log); if (cl == NGX_CHAIN_ERROR) { return NGX_CHAIN_ERROR; } if (cl && cl->buf->in_file) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "file buf in writev " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_CHAIN_ERROR; } send += vec.size; n = ngx_writev(c, &vec); if (n == NGX_ERROR) { return NGX_CHAIN_ERROR; } sent = (n == NGX_AGAIN) ? 0 : n; c->sent += sent; in = ngx_chain_update_sent(in, sent); if (send - prev_send != sent) { wev->ready = 0; return in; } if (send >= limit || in == NULL) { return in; } } } ngx_chain_t * ngx_output_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *in, size_t limit, ngx_log_t *log) { size_t total, size; u_char *prev; ngx_uint_t n; struct iovec *iov; iov = NULL; prev = NULL; total = 0; n = 0; for ( /* void */ ; in && total < limit; in = in->next) { if (ngx_buf_special(in->buf)) { continue; } if (in->buf->in_file) { break; } if (!ngx_buf_in_memory(in->buf)) { ngx_log_error(NGX_LOG_ALERT, log, 0, "bad buf in output chain " "t:%d r:%d f:%d %p %p-%p %p %O-%O", in->buf->temporary, in->buf->recycled, in->buf->in_file, in->buf->start, in->buf->pos, in->buf->last, in->buf->file, in->buf->file_pos, in->buf->file_last); ngx_debug_point(); return NGX_CHAIN_ERROR; } size = in->buf->last - in->buf->pos; if (size > limit - total) { size = limit - total; } if (prev == in->buf->pos) { iov->iov_len += size; } else { if (n == vec->nalloc) { break; } iov = &vec->iovs[n++]; iov->iov_base = (void *) in->buf->pos; iov->iov_len = size; } prev = in->buf->pos + size; total += size; } vec->count = n; vec->size = total; return in; } ssize_t ngx_writev(ngx_connection_t *c, ngx_iovec_t *vec) { ssize_t n; ngx_err_t err; eintr: n = writev(c->fd, vec->iovs, vec->count); ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "writev: %z of %uz", n, vec->size); if (n == -1) { err = ngx_errno; switch (err) { case NGX_EAGAIN: ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "writev() not ready"); return NGX_AGAIN; case NGX_EINTR: ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "writev() was interrupted"); goto eintr; default: c->write->error = 1; ngx_connection_error(c, err, "writev() failed"); return NGX_ERROR; } } return n; }