Mercurial > hg > nginx
view src/os/unix/ngx_channel.c @ 6768:d9c180fcbfa7 stable-1.10
Event pipe: do not set file's thread_handler if not needed.
This fixes a problem with aio threads and sendfile with aio_write switched
off, as observed with range requests after fc72784b1f52 (1.9.13). Potential
problems with sendfile in threads were previously described in 9fd738b85fad,
and this seems to be one of them.
The problem occurred as file's thread_handler was set to NULL by event pipe
code after a sendfile thread task was scheduled. As a result, no sendfile
completion code was executed, and the same buffer was additionally sent
using non-threaded sendfile. Fix is to avoid modifying file's thread_handler
if aio_write is switched off.
Note that with "aio_write on" it is still possible that sendfile will use
thread_handler as set by event pipe. This is believed to be safe though,
as handlers used are compatible.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 01 Sep 2016 20:05:23 +0300 |
parents | 3377f9459e99 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_channel.h> ngx_int_t ngx_write_channel(ngx_socket_t s, ngx_channel_t *ch, size_t size, ngx_log_t *log) { ssize_t n; ngx_err_t err; struct iovec iov[1]; struct msghdr msg; #if (NGX_HAVE_MSGHDR_MSG_CONTROL) union { struct cmsghdr cm; char space[CMSG_SPACE(sizeof(int))]; } cmsg; if (ch->fd == -1) { msg.msg_control = NULL; msg.msg_controllen = 0; } else { msg.msg_control = (caddr_t) &cmsg; msg.msg_controllen = sizeof(cmsg); ngx_memzero(&cmsg, sizeof(cmsg)); cmsg.cm.cmsg_len = CMSG_LEN(sizeof(int)); cmsg.cm.cmsg_level = SOL_SOCKET; cmsg.cm.cmsg_type = SCM_RIGHTS; /* * We have to use ngx_memcpy() instead of simple * *(int *) CMSG_DATA(&cmsg.cm) = ch->fd; * because some gcc 4.4 with -O2/3/s optimization issues the warning: * dereferencing type-punned pointer will break strict-aliasing rules * * Fortunately, gcc with -O1 compiles this ngx_memcpy() * in the same simple assignment as in the code above */ ngx_memcpy(CMSG_DATA(&cmsg.cm), &ch->fd, sizeof(int)); } msg.msg_flags = 0; #else if (ch->fd == -1) { msg.msg_accrights = NULL; msg.msg_accrightslen = 0; } else { msg.msg_accrights = (caddr_t) &ch->fd; msg.msg_accrightslen = sizeof(int); } #endif iov[0].iov_base = (char *) ch; iov[0].iov_len = size; msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_iov = iov; msg.msg_iovlen = 1; n = sendmsg(s, &msg, 0); if (n == -1) { err = ngx_errno; if (err == NGX_EAGAIN) { return NGX_AGAIN; } ngx_log_error(NGX_LOG_ALERT, log, err, "sendmsg() failed"); return NGX_ERROR; } return NGX_OK; } ngx_int_t ngx_read_channel(ngx_socket_t s, ngx_channel_t *ch, size_t size, ngx_log_t *log) { ssize_t n; ngx_err_t err; struct iovec iov[1]; struct msghdr msg; #if (NGX_HAVE_MSGHDR_MSG_CONTROL) union { struct cmsghdr cm; char space[CMSG_SPACE(sizeof(int))]; } cmsg; #else int fd; #endif iov[0].iov_base = (char *) ch; iov[0].iov_len = size; msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_iov = iov; msg.msg_iovlen = 1; #if (NGX_HAVE_MSGHDR_MSG_CONTROL) msg.msg_control = (caddr_t) &cmsg; msg.msg_controllen = sizeof(cmsg); #else msg.msg_accrights = (caddr_t) &fd; msg.msg_accrightslen = sizeof(int); #endif n = recvmsg(s, &msg, 0); if (n == -1) { err = ngx_errno; if (err == NGX_EAGAIN) { return NGX_AGAIN; } ngx_log_error(NGX_LOG_ALERT, log, err, "recvmsg() failed"); return NGX_ERROR; } if (n == 0) { ngx_log_debug0(NGX_LOG_DEBUG_CORE, log, 0, "recvmsg() returned zero"); return NGX_ERROR; } if ((size_t) n < sizeof(ngx_channel_t)) { ngx_log_error(NGX_LOG_ALERT, log, 0, "recvmsg() returned not enough data: %z", n); return NGX_ERROR; } #if (NGX_HAVE_MSGHDR_MSG_CONTROL) if (ch->command == NGX_CMD_OPEN_CHANNEL) { if (cmsg.cm.cmsg_len < (socklen_t) CMSG_LEN(sizeof(int))) { ngx_log_error(NGX_LOG_ALERT, log, 0, "recvmsg() returned too small ancillary data"); return NGX_ERROR; } if (cmsg.cm.cmsg_level != SOL_SOCKET || cmsg.cm.cmsg_type != SCM_RIGHTS) { ngx_log_error(NGX_LOG_ALERT, log, 0, "recvmsg() returned invalid ancillary data " "level %d or type %d", cmsg.cm.cmsg_level, cmsg.cm.cmsg_type); return NGX_ERROR; } /* ch->fd = *(int *) CMSG_DATA(&cmsg.cm); */ ngx_memcpy(&ch->fd, CMSG_DATA(&cmsg.cm), sizeof(int)); } if (msg.msg_flags & (MSG_TRUNC|MSG_CTRUNC)) { ngx_log_error(NGX_LOG_ALERT, log, 0, "recvmsg() truncated data"); } #else if (ch->command == NGX_CMD_OPEN_CHANNEL) { if (msg.msg_accrightslen != sizeof(int)) { ngx_log_error(NGX_LOG_ALERT, log, 0, "recvmsg() returned no ancillary data"); return NGX_ERROR; } ch->fd = fd; } #endif return n; } ngx_int_t ngx_add_channel_event(ngx_cycle_t *cycle, ngx_fd_t fd, ngx_int_t event, ngx_event_handler_pt handler) { ngx_event_t *ev, *rev, *wev; ngx_connection_t *c; c = ngx_get_connection(fd, cycle->log); if (c == NULL) { return NGX_ERROR; } c->pool = cycle->pool; rev = c->read; wev = c->write; rev->log = cycle->log; wev->log = cycle->log; rev->channel = 1; wev->channel = 1; ev = (event == NGX_READ_EVENT) ? rev : wev; ev->handler = handler; if (ngx_add_conn && (ngx_event_flags & NGX_USE_EPOLL_EVENT) == 0) { if (ngx_add_conn(c) == NGX_ERROR) { ngx_free_connection(c); return NGX_ERROR; } } else { if (ngx_add_event(ev, event, 0) == NGX_ERROR) { ngx_free_connection(c); return NGX_ERROR; } } return NGX_OK; } void ngx_close_channel(ngx_fd_t *fd, ngx_log_t *log) { if (close(fd[0]) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "close() channel failed"); } if (close(fd[1]) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "close() channel failed"); } }