ngx_link_func_init_cycle() not found on FreeBSD

[interkosmos]

The following basic example is not accepted by the nginx-link-function module on FreeBSD 12 with nginx 1.18 :

#include <stdio.h>
#include <ngx_link_func_module.h>

int is_service_on = 0;

void ngx_link_func_init_cycle(ngx_link_func_cycle_t* cycle) {
    ngx_link_func_cyc_log(info, cycle, "%s", "starting application");

    is_service_on=1;
}

void greeting(ngx_link_func_ctx_t *ctx) {
    ngx_link_func_log_info(ctx, "Calling back and log from my_app_simple_get");

    ngx_link_func_write_resp(
        ctx,
        200,
        "200 OK",
        "text/plain",
        "greeting from ngx_link_func testing",
        sizeof("greeting from ngx_link_func testing")-1
    );
}

void ngx_link_func_exit_cycle(ngx_link_func_cycle_t* cyc) {
    ngx_link_func_cyc_log(info, cyc, "%s\n", "Shutting down/reloading the Application");

    is_service_on = 0;
}

Compilation:

$ gcc -shared -fPIC -o hello.so hello.c

The shared library is then loaded with:

    server {
        listen       80;
        server_name  localhost;
        ngx_link_func_lib "/usr/local/etc/nginx/hello.so";

        location = /greeting {
            ngx_link_func_call "greeting";
        } 
    }

Starting nginx fails with:

# service nginx start
nginx: [error] function ngx_link_func_init_cycle(ngx_link_func_cycle_t *cycle) not found in "/usr/local/etc/nginx/hello.so", at least create an empty init function block
 Undefined symbol "_nss_cache_cycle_prevention_function" in /usr/local/etc/nginx/nginx.conf:126

But the shared library contains the wanted function:

# nm -D hello.so
                 w _ITM_deregisterTMCloneTable
                 w _ITM_registerTMCloneTable
                 w __cxa_finalize
00000000000007f4 T _fini
0000000000000510 T _init
00000000000006f7 T greeting
0000000000200bb8 B is_service_on
                 U ngx_link_func_cyc_log_info
0000000000000745 T ngx_link_func_exit_cycle
0000000000000695 T ngx_link_func_init_cycle
                 U ngx_link_func_log_info
                 U ngx_link_func_write_resp
                 U snprintf

[interkosmos]

A possible fix is to simply call dlerror() before dlsym(scf->_app, (const char*)"ngx_link_func_init_cycle") and dlsym(scf->_app, (const char*)"ngx_link_func_exit_cycle")in ngx_link_func_module.c to clear the error state.

[Taymindis]

Hi, it would be great if you could fork and pull request to fix this compatibility issue.

#if __FreeBSD__ 
 
 - flush the dlerror().

#endif

[Taymindis]

Hi, Thanks for reporting, new code checked in fixed.

[interkosmos]

Thank you. Do you mind publishing a new release soon? The FreeBSD port of nginx could be updated then to be compiled with the fix.

[Taymindis]

HI @interkosmos , I have just deployed the new release.

https://github.com/Taymindis/nginx-link-function/releases/tag/3.2.2

[interkosmos]

Thank you for the rapid release. The FreeBSD port of nginx has been updated to include the fix. I recompiled nginx, but unfortunately, the issue is still not resolved. The very same error persists.

[Taymindis]

@interkosmos
is your OS FreeBSD or other BSD?

Could you try compile a simple C program and embedded this snippet

#if __FreeBSD__
   printf("I am FreeBSD");
#endif

[interkosmos]

Example program:

/* test.c */
#include <stdio.h>

int main(void)
{
#if __FreeBSD__
   printf("I am FreeBSD");
#endif

    return 0;
}

Output:

$ uname -a
FreeBSD endeavour 12.1-RELEASE-p3 FreeBSD 12.1-RELEASE-p3 GENERIC  amd64
$ cc -o test test.c
$ ./test
I am FreeBSD

[Taymindis]

My FreeBSD VM version is

12.1-RELEASE r354233 GENERIC amd64

I could not replicate the issue anymore after i fixed it. The only different is I was not installing from Ports. Maybe you can show me how you install it with Nginx?

Please skype me if you're free live:.cid.307deb505c0a691

Thanks

[interkosmos]

Sorry, I’ve no Skype. But what I did was simply building the Port www/nginx v. 1.18.0_4,2 with LINK option enabled in Poudriere (cd /usr/local/ports/www/nginx/ && make config && make && make install or portmaster www/nginx should work equally). Then, I called pkg install www/nginx to install the (Poudriere-built) package, and service nginx start to start the daemon.

[Taymindis]

I replicated the issue, I think the issue is happened when starting nginx for validity checking, I have fixed them and release 3.2.3.

Thanks

[interkosmos]

Thank you, the FreeBSD port now builds successfully and the issue seems to be solved. I’ve sent the required patches to the port maintainer and suppose that the port will be updated soon.