view docs/man/nginx.8 @ 7710:097f578a4a8f

HTTP/2: fixed segfault on DATA frames after 400 errors. If 400 errors were redirected to an upstream server using the error_page directive, DATA frames from the client might cause segmentation fault due to null pointer dereference. The bug had appeared in 6989:2c4dbcd6f2e4 (1.13.0). Fix is to skip such frames in ngx_http_v2_state_read_data() (similarly to 7561:9f1f9d6e056a). With the fix, behaviour of 400 errors in HTTP/2 is now similar to one in HTTP/1.x, that is, nginx doesn't try to read the request body. Note that proxying 400 errors, as well as other early stage errors, to upstream servers might not be a good idea anyway. These errors imply that reading and processing of the request (and the request headers) wasn't complete, and proxying of such incomplete request might lead to various errors. Reported by Chenglong Zhang.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 23 Sep 2020 19:50:49 +0300
parents 4718a646187a
children f18db38a9826
line wrap: on
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.\"
.\" Copyright (C) 2010, 2019 Sergey A. Osokin
.\" Copyright (C) Nginx, Inc.
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.Dd December 5, 2019
.Dt NGINX 8
.Os
.Sh NAME
.Nm nginx
.Nd "HTTP and reverse proxy server, mail proxy server"
.Sh SYNOPSIS
.Nm
.Op Fl ?hqTtVv
.Op Fl c Ar file
.Op Fl g Ar directives
.Op Fl p Ar prefix
.Op Fl s Ar signal
.Sh DESCRIPTION
.Nm
(pronounced
.Dq engine x )
is an HTTP and reverse proxy server, a mail proxy server, and a generic
TCP/UDP proxy server.
It is known for its high performance, stability, rich feature set, simple
configuration, and low resource consumption.
.Pp
The options are as follows:
.Bl -tag -width ".Fl d Ar directives"
.It Fl ?\& , h
Print help.
.It Fl c Ar file
Use an alternative configuration
.Ar file .
.It Fl g Ar directives
Set global configuration directives.
See
.Sx EXAMPLES
for details.
.It Fl p Ar prefix
Set the prefix path.
The default value is
.Pa %%PREFIX%% .
.It Fl q
Suppress non-error messages during configuration testing.
.It Fl s Ar signal
Send a signal to the master process.
The argument
.Ar signal
can be one of:
.Cm stop , quit , reopen , reload .
The following table shows the corresponding system signals:
.Pp
.Bl -tag -width ".Cm reopen" -compact
.It Cm stop
.Dv SIGTERM
.It Cm quit
.Dv SIGQUIT
.It Cm reopen
.Dv SIGUSR1
.It Cm reload
.Dv SIGHUP
.El
.It Fl T
Same as
.Fl t ,
but additionally dump configuration files to standard output.
.It Fl t
Do not run, just test the configuration file.
.Nm
checks the configuration file syntax and then tries to open files
referenced in the configuration file.
.It Fl V
Print the
.Nm
version, compiler version, and
.Pa configure
script parameters.
.It Fl v
Print the
.Nm
version.
.El
.Sh SIGNALS
The master process of
.Nm
can handle the following signals:
.Pp
.Bl -tag -width ".Dv SIGINT , SIGTERM" -compact
.It Dv SIGINT , SIGTERM
Shut down quickly.
.It Dv SIGHUP
Reload configuration, start the new worker process with a new
configuration, and gracefully shut down old worker processes.
.It Dv SIGQUIT
Shut down gracefully.
.It Dv SIGUSR1
Reopen log files.
.It Dv SIGUSR2
Upgrade the
.Nm
executable on the fly.
.It Dv SIGWINCH
Shut down worker processes gracefully.
.El
.Pp
While there is no need to explicitly control worker processes normally,
they support some signals too:
.Pp
.Bl -tag -width ".Dv SIGINT , SIGTERM" -compact
.It Dv SIGTERM
Shut down quickly.
.It Dv SIGQUIT
Shut down gracefully.
.It Dv SIGUSR1
Reopen log files.
.El
.Sh DEBUGGING LOG
To enable a debugging log, reconfigure
.Nm
to build with debugging:
.Pp
.Dl "./configure --with-debug ..."
.Pp
and then set the
.Cm debug
level of the
.Va error_log :
.Pp
.Dl "error_log /path/to/log debug;"
.Pp
It is also possible to enable the debugging for a particular IP address:
.Bd -literal -offset indent
events {
	debug_connection 127.0.0.1;
}
.Ed
.Sh ENVIRONMENT
The
.Ev NGINX
environment variable is used internally by
.Nm
and should not be set directly by the user.
.Sh FILES
.Bl -tag -width indent
.It Pa %%PID_PATH%%
Contains the process ID of
.Nm .
The contents of this file are not sensitive, so it can be world-readable.
.It Pa %%CONF_PATH%%
The main configuration file.
.It Pa %%ERROR_LOG_PATH%%
Error log file.
.El
.Sh EXIT STATUS
Exit status is 0 on success, or 1 if the command fails.
.Sh EXAMPLES
Test configuration file
.Pa ~/mynginx.conf
with global directives for PID and quantity of worker processes:
.Bd -literal -offset indent
nginx -t -c ~/mynginx.conf \e
	-g "pid /var/run/mynginx.pid; worker_processes 2;"
.Ed
.Sh SEE ALSO
.\"Xr nginx.conf 5
.\"Pp
Documentation at
.Pa http://nginx.org/en/docs/ .
.Pp
For questions and technical support, please refer to
.Pa http://nginx.org/en/support.html .
.Sh HISTORY
Development of
.Nm
started in 2002, with the first public release on October 4, 2004.
.Sh AUTHORS
.An -nosplit
.An Igor Sysoev Aq igor@sysoev.ru .
.Pp
This manual page was originally written by
.An Sergey A. Osokin Aq osa@FreeBSD.org.ru
as a result of compiling many
.Nm
documents from all over the world.