Allow loading FFI bindings through ffi.preload directive

[dstogov]

No description provided.

[remicollet]

@dstogov thanks for your work

Can you please clarify how to use it ?
ffi.preload is for the headers, right ?
And about the class which use it ?

[dstogov]

$ php -dffi.preload=ext/ffi/tests/300.h -r 'FFI::scope("TEST_300")->printf("Hello World from %s!\n", "PHP");'

[dstogov]

Just remove FFI::load() and add "ffi.preload" directive.

[remicollet]

OK, indeed it works this way.

Could be nice to disallow opcache.preload... when FFI is used....
Going to be confusing for users

[dstogov]

You probably mean FFI::load()?
It's not going to work if PHP started as "root" and uses "opcache.preload_user" to change credentials.
I'm going to make FFI::load() to fail (with corresponding error message) in this case.
@remicollet is this the same what you suggest.

[remicollet]

Hmm... no trying to understand an d avoid segfault ;)

Looks like a simple call with a static property is enough to raise a segfault

# php -derror_reporting=-1 -dopcache.log_verbosity_level=4 -d zend_extension=opcache.so  -d opcache.enable=1 -d opcache.enable_cli=1  -d opcache.preload_user=remi -d opcache.preload=preload-foo.inc foo.php
Tue Oct 22 15:03:25 2019 (26901): Message Cached script '$PRELOAD$'
Tue Oct 22 15:03:25 2019 (26901): Message Cached script '/home/rpmbuild/SPECS/remirepo/tools/ffi-examples/preload-foo.inc'
Erreur de segmentation (core dumped)

So seems another issue (not FFI related)
preload-foo.inc is a simple

<?php
namespace Remi;

class Foo {
	static private $single = NULL;
}

So perhaps the reason for this segfault reported in #78713 (the static property is used as singleton)

[dstogov]

@remicollet the crash should be fixed by previous commit. Could you please recheck.

[remicollet]

@dstogov indeed, segfault with singleton is fixed.

[remicollet]

Looks like it works as expected

• FFI::load in the preloaded class constructor (singleton)
• ffi.preload and FFI::scope in the preloaded class constructor

Without this PR, and only with the "Allocate" fix, I don't encounter any segfault, but "FFI::scope" fails (so FFI::load is always used)

So the warning is indeed needed.

Great work!

[cmb69]

Fix compilation on Windows:

 ext/opcache/ZendAccelerator.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ext/opcache/ZendAccelerator.c b/ext/opcache/ZendAccelerator.c
index 54e6fdf6cf..704e1c38d9 100644
--- a/ext/opcache/ZendAccelerator.c
+++ b/ext/opcache/ZendAccelerator.c
@@ -4590,9 +4590,11 @@ static int accel_finish_startup(void)
 		sapi_module.ub_write = preload_ub_write;
 		sapi_module.flush = preload_flush;
 
+#ifndef ZEND_WIN32
 		if (in_child) {
 			CG(compiler_options) |= ZEND_COMPILE_PRELOAD_IN_CHILD;
 		}
+#endif
 		CG(compiler_options) |= ZEND_COMPILE_PRELOAD;
 		CG(compiler_options) |= ZEND_COMPILE_HANDLE_OP_ARRAY;
 		CG(compiler_options) |= ZEND_COMPILE_IGNORE_INTERNAL_CLASSES;

[dstogov]

@cmb69 thanks

[cmb69]

@dstogov, you're welcome!

[dstogov]

Merged into PHP-7.4 as 1417352