Mercurial > hg > nginx
view src/os/unix/ngx_recv.c @ 7948:a2613fc1bce5
Fixed sendfile() limit handling on Linux.
On Linux starting with 2.6.16, sendfile() silently limits all operations
to MAX_RW_COUNT, defined as (INT_MAX & PAGE_MASK). This incorrectly
triggered the interrupt check, and resulted in 0-sized writev() on the
next loop iteration.
Fix is to make sure the limit is always checked, so we will return from
the loop if the limit is already reached even if number of bytes sent is
not exactly equal to the number of bytes we've tried to send.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 29 Oct 2021 20:21:51 +0300 |
parents | efd71d49bde0 |
children | 5119c8150478 |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> ssize_t ngx_unix_recv(ngx_connection_t *c, u_char *buf, size_t size) { ssize_t n; ngx_err_t err; ngx_event_t *rev; rev = c->read; #if (NGX_HAVE_KQUEUE) if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) { ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0, "recv: eof:%d, avail:%d, err:%d", rev->pending_eof, rev->available, rev->kq_errno); if (rev->available == 0) { if (rev->pending_eof) { rev->ready = 0; rev->eof = 1; if (rev->kq_errno) { rev->error = 1; ngx_set_socket_errno(rev->kq_errno); return ngx_connection_error(c, rev->kq_errno, "kevent() reported about an closed connection"); } return 0; } else { rev->ready = 0; return NGX_AGAIN; } } } #endif #if (NGX_HAVE_EPOLLRDHUP) if (ngx_event_flags & NGX_USE_EPOLL_EVENT) { ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "recv: eof:%d, avail:%d", rev->pending_eof, rev->available); if (rev->available == 0 && !rev->pending_eof) { rev->ready = 0; return NGX_AGAIN; } } #endif do { n = recv(c->fd, buf, size, 0); ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0, "recv: fd:%d %z of %uz", c->fd, n, size); if (n == 0) { rev->ready = 0; rev->eof = 1; #if (NGX_HAVE_KQUEUE) /* * on FreeBSD recv() may return 0 on closed socket * even if kqueue reported about available data */ if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) { rev->available = 0; } #endif return 0; } if (n > 0) { #if (NGX_HAVE_KQUEUE) if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) { rev->available -= n; /* * rev->available may be negative here because some additional * bytes may be received between kevent() and recv() */ if (rev->available <= 0) { if (!rev->pending_eof) { rev->ready = 0; } rev->available = 0; } return n; } #endif #if (NGX_HAVE_FIONREAD) if (rev->available >= 0) { rev->available -= n; /* * negative rev->available means some additional bytes * were received between kernel notification and recv(), * and therefore ev->ready can be safely reset even for * edge-triggered event methods */ if (rev->available < 0) { rev->available = 0; rev->ready = 0; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "recv: avail:%d", rev->available); } else if ((size_t) n == size) { if (ngx_socket_nread(c->fd, &rev->available) == -1) { n = ngx_connection_error(c, ngx_socket_errno, ngx_socket_nread_n " failed"); break; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "recv: avail:%d", rev->available); } #endif #if (NGX_HAVE_EPOLLRDHUP) if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) && ngx_use_epoll_rdhup) { if ((size_t) n < size) { if (!rev->pending_eof) { rev->ready = 0; } rev->available = 0; } return n; } #endif if ((size_t) n < size && !(ngx_event_flags & NGX_USE_GREEDY_EVENT)) { rev->ready = 0; } return n; } err = ngx_socket_errno; if (err == NGX_EAGAIN || err == NGX_EINTR) { ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "recv() not ready"); n = NGX_AGAIN; } else { n = ngx_connection_error(c, err, "recv() failed"); break; } } while (err == NGX_EINTR); rev->ready = 0; if (n == NGX_ERROR) { rev->error = 1; } return n; }