#40738 [NEW]: php fastcgi on windows hangs if 'reuse-connnections' is enabled

[sriram dot natarajan at sun dot com]

From: sriram dot natarajan at sun dot com
Operating system: windows
PHP version: 5.2.1
PHP Bug Type: *General Issues
Bug description: php fastcgi on windows hangs if 'reuse-connnections' is enabled

Description:
------------
currently, when we use Php 5.2.x as 'fastcgi' plugin with web server +
fastcgi support and enable 'reuse-connection' , then the php processes
does not shutdown correctly.

here is the issue

During shutdown, the plugin sends TERM signal to the PHP primordial which
in turn sends TERM to its child processes. In case of reuse-connection=1,
the child PHP process which has served the request, would be waiting in
"read" (within a "while" loop). If, at this time, it receives a TERM
signal, then this read gets interrupted and the signal handler gets
executed which sets the variable "in_shutdown" to true. Since "read" is
inside the loop and there is no check for this in_shutdown variable within
the loop, the PHP process continues to wait in "read".

The following change in the PHP code fixed this issue.

File: <php src dir>/sapi/cgi/fastcgi.c
---------------------------------------------------------------
static inline ssize_t safe_read(fcgi_request *req, const void *buf, size_t
count)
{
int ret;
size_t n = 0;

do {
ret = read(req->fd, ((char*)buf)+n, count-n);
// This check is needed to avoid looping during shutdown.
+ if(in_shutdown) { // missing code
+ return -1;
} else if (ret > 0) {
n += ret;
} else if (ret == 0 && errno == 0) {
return n;
} else if (ret <= 0 && errno != 0 && errno != EINTR) {
return ret;
}
} while (n != count);
return n;
}
---------------------------------------------------------------



--
Edit bug report at [url]http://bugs.php.net/?id=40738&edit=1[/url]
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[tony2001@php.net]

ID: 40738
Updated by: [email]tony2001@php.net[/email]
Reported By: sriram dot natarajan at sun dot com
-Status: Open
+Status: Assigned
-Bug Type: *General Issues
+Bug Type: CGI related
Operating System: windows
PHP Version: 5.2.1
-Assigned To:
+Assigned To: dmitry


Previous Comments:
------------------------------------------------------------------------

[2007-03-06 08:37:00] sriram dot natarajan at sun dot com

Description:
------------
currently, when we use Php 5.2.x as 'fastcgi' plugin with web server +
fastcgi support and enable 'reuse-connection' , then the php processes
does not shutdown correctly.

here is the issue

During shutdown, the plugin sends TERM signal to the PHP primordial
which in turn sends TERM to its child processes. In case of
reuse-connection=1, the child PHP process which has served the request,
would be waiting in "read" (within a "while" loop). If, at this time, it
receives a TERM signal, then this read gets interrupted and the signal
handler gets executed which sets the variable "in_shutdown" to true.
Since "read" is inside the loop and there is no check for this
in_shutdown variable within the loop, the PHP process continues to wait
in "read".

The following change in the PHP code fixed this issue.

File: <php src dir>/sapi/cgi/fastcgi.c
---------------------------------------------------------------
static inline ssize_t safe_read(fcgi_request *req, const void *buf,
size_t count)
{
int ret;
size_t n = 0;

do {
ret = read(req->fd, ((char*)buf)+n, count-n);
// This check is needed to avoid looping during
shutdown.
+ if(in_shutdown) { // missing code
+ return -1;
} else if (ret > 0) {
n += ret;
} else if (ret == 0 && errno == 0) {
return n;
} else if (ret <= 0 && errno != 0 && errno != EINTR) {
return ret;
}
} while (n != count);
return n;
}
---------------------------------------------------------------




------------------------------------------------------------------------


--
Edit this bug report at [url]http://bugs.php.net/?id=40738&edit=1[/url]

[dmitry@php.net]

ID: 40738
Updated by: [email]dmitry@php.net[/email]
Reported By: sriram dot natarajan at sun dot com
-Status: Assigned
+Status: Feedback
Bug Type: CGI related
Operating System: windows
PHP Version: 5.2.1
Assigned To: dmitry
New Comment:

'reuse-connection' is probably some setting of web-server or FastCGI
plugin, but I don't understand which web-server and which FastCGI
plugin do you mean.

Your patch is not correct, because PHP must finish request processing
and die only after that. This allows graceful restart without request
dropping.

In case if web-server or FastCGI plugin really decide drop requests, it
must just close connection to PHP and it will exit from safe_read() loop
because of broken pipe.


Previous Comments:
------------------------------------------------------------------------

[2007-03-06 08:37:00] sriram dot natarajan at sun dot com

Description:
------------
currently, when we use Php 5.2.x as 'fastcgi' plugin with web server +
fastcgi support and enable 'reuse-connection' , then the php processes
does not shutdown correctly.

here is the issue

During shutdown, the plugin sends TERM signal to the PHP primordial
which in turn sends TERM to its child processes. In case of
reuse-connection=1, the child PHP process which has served the request,
would be waiting in "read" (within a "while" loop). If, at this time, it
receives a TERM signal, then this read gets interrupted and the signal
handler gets executed which sets the variable "in_shutdown" to true.
Since "read" is inside the loop and there is no check for this
in_shutdown variable within the loop, the PHP process continues to wait
in "read".

The following change in the PHP code fixed this issue.

File: <php src dir>/sapi/cgi/fastcgi.c
---------------------------------------------------------------
static inline ssize_t safe_read(fcgi_request *req, const void *buf,
size_t count)
{
int ret;
size_t n = 0;

do {
ret = read(req->fd, ((char*)buf)+n, count-n);
// This check is needed to avoid looping during
shutdown.
+ if(in_shutdown) { // missing code
+ return -1;
} else if (ret > 0) {
n += ret;
} else if (ret == 0 && errno == 0) {
return n;
} else if (ret <= 0 && errno != 0 && errno != EINTR) {
return ret;
}
} while (n != count);
return n;
}
---------------------------------------------------------------




------------------------------------------------------------------------


--
Edit this bug report at [url]http://bugs.php.net/?id=40738&edit=1[/url]