uwsgi with php plugin doesn't compile

[gdamjan]

Describe the bug
when enabling the php plugin in the uwsgi package the compile of the plugin fails.

To Reproduce
Steps to reproduce the behavior:

1. nix-build -E 'with import <nixpkgs> {}; uwsgi.override { plugins=[ "php" ]; }'

Screenshots

*** uWSGI is ready, launch it with ./uwsgi ***
using profile: buildconf/nixos.ini
detected include path: ['/nix/store/vb1fh8zqdcs7n3hvn8awlrpdfnic6zjg-gcc-9.3.0/lib/gcc/x86_64-unknown-linux-gnu/9.3.0/include', '/nix/store/vb1fh8zqdcs7n3hvn8awlrpdfnic6zjg-gcc-9.3.0/include', '/nix/store/vb1fh8zqdcs7n3hvn8awlrpdfnic6zjg-gcc-9.3.0/lib/gcc/x86_64-unknown-linux-gnu/9.3.0/include-fixed', '/nix/store/vbs3xx1b5i5bzf1sjkz2lkmz7b8cy92y-glibc-2.30-dev/include']
*** uWSGI building and linking plugin plugins/php ***
/bin/sh: php-config: not found
/bin/sh: php-config: not found
/bin/sh: php-config: not found
/bin/sh: php-config: not found
[gcc] /nix/store/yjg3pdnwgynl1sz9rkc5gyjcgjamgfi9-uwsgi-2.0.18/lib/uwsgi/php_plugin.so
In file included from plugins/php/php_plugin.c:1:
plugins/php/common.h:1:10: fatal error: php.h: No such file or directory
    1 | #include "php.h"
      |          ^~~~~~~
compilation terminated.
In file included from plugins/php/session.c:1:
plugins/php/common.h:1:10: fatal error: php.h: No such file or directory
    1 | #include "php.h"
      |          ^~~~~~~
compilation terminated.
*** unable to build php plugin ***

Additional context

The uwsgi build system tries to invoke php-config to get the include paths for the compile, but php-config is not in the path (it's in the php.dev package). This can be fixed by setting the UWSGICONFIG_PHPDIR = "${php-embed.unwrapped.dev}"; environment variable. uwsgi then finds php.h, but fails on #include "ext/session/php_session.h" which is in extensions.session.dev, and under a different path in the store.

https://github.com/unbit/uwsgi/blob/master/plugins/php/common.h
https://github.com/unbit/uwsgi/blob/master/plugins/php/uwsgiplugin.py

I'll try to find a better solution next.

Notify maintainers
@abbradar @schneefux @globin

Metadata
Maintainer information:

 - system: `"x86_64-linux"`
 - host os: `Linux 5.8.7-arch1-1, Alpine Linux, noversion`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.3.6`
 - channels(root): `"nixpkgs-20.09pre228453.dcb64ea42e6"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixpkgs`

[gdamjan]

trying to fix the issue here
master...gdamjan:fix-uwsgi-php-try1

includes are fine, but php-config returns an empty --ldflags list, so linkig fails with:

*** uWSGI building and linking plugin plugins/php ***
[gcc] /nix/store/p9mzbjm5fb1sv2f3gyzjzg5km1afkiwh-uwsgi-2.0.19.1/lib/uwsgi/php_plugin.so
/nix/store/zp4vhfn31ky68xy0s6mssxh4c90z9v9a-binutils-2.31.1/bin/ld: cannot find -largon2
collect2: error: ld returned 1 exit status

[gdamjan]

With the above changes the compile command is (stripped of some of the options and defines):

gcc
-fPIC
-shared
-o /nix/store/98l6in3hxjv3zglaajkhacpw0jfqsby0-uwsgi-2.0.19.1/lib/uwsgi/php_plugin.so
…
-I/nix/store/6a7ys7yzpnzwirbch4qycz2lxix2gm96-php-session-7.4.8-dev/include
-I/nix/store/ckklsxzdp10myy6i9a5qdy1cxxvqkbfa-pcre-8.44-dev/include
-I/nix/store/90n4d0cjgiw190zvq501q1p6j4xsn1r9-jansson-2.13.1/include
-I/nix/store/na6yq1y381j78677iph8p8l92igqbg84-php-7.4.8-dev/include/php
-I/nix/store/na6yq1y381j78677iph8p8l92igqbg84-php-7.4.8-dev/include/php/main
-I/nix/store/na6yq1y381j78677iph8p8l92igqbg84-php-7.4.8-dev/include/php/TSRM
-I/nix/store/na6yq1y381j78677iph8p8l92igqbg84-php-7.4.8-dev/include/php/Zend
-I/nix/store/na6yq1y381j78677iph8p8l92igqbg84-php-7.4.8-dev/include/php/ext
-I/nix/store/na6yq1y381j78677iph8p8l92igqbg84-php-7.4.8-dev/include/php/ext/date/lib
…
-lcrypt
-largon2
-lresolv
-lcrypt
-lrt
-lm
-ldl
-lxml2
-lpcre2-8
-lcrypt
-largon2
-lxml2
-lcrypt
-lphp7

Obviously there are no -L flags to gcc.

[gdamjan]

more success with these changes master...gdamjan:fix-uwsgi-php-try2 now uwsgi compiles and links fine, but at runtime it fails with

!!! UNABLE to load uWSGI plugin: /nix/store/pd2031xdjprr1vlwphm1f9l41zkdyif1-uwsgi-2.0.19.1/lib/uwsgi/php_plugin.so: undefined symbol: php_session_create_id !!!

[azazel75]

Have you had a complete success on this? I'm stuck on it but I must say I'm no PHP nor uwsgi expert

[gdamjan]

@azazel75 yes, see the PR #97536. I'm using that to run a couple of php apps.

Unfortunetlly, it seems there are no reviewers so there's no progress on merging it.