Change in ngx_conf_merge_ptr_value for 0.5.33

Server NGINX
1

Igor, do you have made some changes in the ngx_conf_merge_ptr_value
function?

In mod_wsgi I have:
ngx_conf_merge_ptr_value(conf->callable_object, prev->callable_object,
“application”);

for directive wsgi_application_callable.

With 0.5.32 and 0.6.16, when the directive is not supplied, its value is
“application”.

With 0.5.33 it is NULL.

conf->callable_object is a char *.

Thanks Manlio P.

2

On Sat, Nov 24, 2007 at 06:26:02PM +0100, Manlio P. wrote:

“application”.

With 0.5.33 it is NULL.

conf->callable_object is a char *.

Yes, it was changed (however, svn log says it was in 0.5.32 and 0.6.10):

#define ngx_conf_merge_ptr_value(conf, prev, default)
\

  • if (conf == NULL) {
    \
  •    conf = (prev == NULL) ? default : prev;

\

  • if (conf == NGX_CONF_UNSET_PTR) {
    \
  •    conf = (prev == NGX_CONF_UNSET_PTR) ? default : prev;


}

3

Igor S. ha scritto:

With 0.5.32 and 0.6.16, when the directive is not supplied, its value is
“application”.

With 0.5.33 it is NULL.

conf->callable_object is a char *.

Yes, it was changed (however, svn log says it was in 0.5.32 and 0.6.10):

Right, sorry.
I was using 0.5.31, and with 0.6.10 I have not tested this problem :).

#define ngx_conf_merge_ptr_value(conf, prev, default) \

  • if (conf == NULL) { \
  •    conf = (prev == NULL) ? default : prev;                              \
  • if (conf == NGX_CONF_UNSET_PTR) { \
  •    conf = (prev == NGX_CONF_UNSET_PTR) ? default : prev;                \
    }

Uhm, but now if I use NGX_CONF_UNSET_PTR as default value, it will no
more works with older version, right?

Ok, not a big problem.

Thanks Manlio P.

4

Manlio P. ha scritto:

2007/11/25 18:07:08 [emerg] 19458#0: “wsgi_callable_object” directive is
duplicate in nginx-simple.conf:51

Ok, I have fixed the problem with my code.

but I get a segmentation fault:

ngx_conf_set_str_array_slot(ngx_conf_t *cf, ngx_command_t *cmd, void
*conf)
{
char *p = conf;

 ngx_str_t         *value, *s;
 ngx_array_t      **a;
 ngx_conf_post_t   *post;

 a = (ngx_array_t **) (p + cmd->offset);
  • if (*a == NULL) {
  • if (*a == NGX_CONF_UNSET_PTR) {

Manlio P.

5

Igor S. ha scritto:

  • if (conf == NULL) { \
  •    conf = (prev == NULL) ? default : prev;                              \
  • if (conf == NGX_CONF_UNSET_PTR) { \
  •    conf = (prev == NGX_CONF_UNSET_PTR) ? default : prev;                \
    }

There is somethig wrong, here.
I’m using now 0.5.33.

In ngx_http_wsgi_create_loc_conf I set:
wlcf->callable_object = NGX_CONF_UNSET_PTR;

and in ngx_http_wsgi_merge_loc_conf:
ngx_conf_merge_ptr_value(conf->callable_object, prev->callable_object,
“application”);

When directive wsgi_callable_object is not defined, then it defaults to
“application”.

However if I define the directive in configuration file:
location / {
wsgi_alias /usr/local/nginx/nginx-simple.py;
wsgi_callable_object application;
}

I get a:
2007/11/25 18:07:08 [emerg] 19458#0: “wsgi_callable_object” directive is
duplicate in nginx-simple.conf:51

To understand how this works, I have tested fastcgi_catch_stderr (not
documented):

location /test {
fastcgi_pass 127.0.0.1:9000;
fastcgi_catch_stderr ops;
}

but I get a segmentation fault:

(gdb) run -c nginx-simple.conf
Starting program: /usr/local/nginx/sbin/nginx -c nginx-simple.conf
Failed to read a valid object file image from memory.
[Thread debugging using libthread_db enabled]
[New Thread -1213540672 (LWP 19510)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1213540672 (LWP 19510)]
ngx_array_push (a=0xffffffff) at src/core/ngx_array.c:59
59 if (a->nelts == a->nalloc) {
(gdb) bt
#0 ngx_array_push (a=0xffffffff) at src/core/ngx_array.c:59
#1 0x08058761 in ngx_conf_set_str_array_slot (cf=0xbf83df4c,
cmd=0x80ac618, conf=0x80cead4) at src/core/ngx_conf_file.c:935
#2 0x08059715 in ngx_conf_parse (cf=0xbf83df4c, filename=0x0) at
src/core/ngx_conf_file.c:336
#3 0x0806b7f7 in ngx_http_core_location (cf=0xbf83df4c, cmd=0x80a7aac,
dummy=0x80ccf34) at src/http/ngx_http_core_module.c:1915
#4 0x08059715 in ngx_conf_parse (cf=0xbf83df4c, filename=0x0) at
src/core/ngx_conf_file.c:336
#5 0x0806ba25 in ngx_http_core_server (cf=0xbf83df4c, cmd=0x80a79b0,
dummy=0x80c31f0) at src/http/ngx_http_core_module.c:1706
#6 0x08059715 in ngx_conf_parse (cf=0xbf83df4c, filename=0x0) at
src/core/ngx_conf_file.c:336
#7 0x080682c1 in ngx_http_block (cf=0xbf83df4c, cmd=0x80a77e0,
conf=0x80c2cd8) at src/http/ngx_http.c:218
#8 0x08059715 in ngx_conf_parse (cf=0xbf83df4c, filename=0x80c263c) at
src/core/ngx_conf_file.c:336
#9 0x080571df in ngx_init_cycle (old_cycle=0xbf83dfbc) at
src/core/ngx_cycle.c:216
#10 0x0804d8b9 in main (argc=3, argv=0xbf83e104) at src/core/nginx.c:291

So this seems a bug in the NGX_CONF_UNSET_PTR / ngx_conf_merge_ptr_value
logic.

Thanks Manlio P.