C로 기본 PHP 확장 기능 작성

PHP의 네이티브 코드

빌드 도구 체인

# Install build prerequisites (Debian/Ubuntu)
sudo apt install php-dev build-essential

# Confirm the tools exist
phpize --version
php-config --extension-dir   # where the .so will be installed

config.m4

dnl config.m4 for the 'hello' extension
PHP_ARG_ENABLE([hello],
  [whether to enable hello support],
  [AS_HELP_STRING([--enable-hello], [Enable hello])],
  [no])

if test "$PHP_HELLO" != "no"; then
  PHP_NEW_EXTENSION(hello, hello.c, $ext_shared)
fi

확장 모듈 헤더

/* hello.c — includes */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "php.h"
#include "ext/standard/info.h"
#include "hello_arginfo.h"   /* generated from stub */

인수 정보 스텁

<?php
// hello.stub.php — describes the native function's signature
/** @generate-class-entries */

function hello_greet(string $name): string {}
?>

함수 구현하기

/* hello.c — the native function */
PHP_FUNCTION(hello_greet)
{
    char *name;
    size_t name_len;

    ZEND_PARSE_PARAMETERS_START(1, 1)
        Z_PARAM_STRING(name, name_len)
    ZEND_PARSE_PARAMETERS_END();

    /* Build "Hello, <name>!" into a new zend_string */
    zend_string *result = strpprintf(0, "Hello, %s!", name);
    RETURN_STR(result);   /* hands ownership to the engine */
}

모듈 진입점

/* hello.c — module wiring */
zend_module_entry hello_module_entry = {
    STANDARD_MODULE_HEADER,
    "hello",                 /* extension name */
    ext_functions,           /* function table from arginfo */
    NULL,                    /* MINIT  (module startup)  */
    NULL,                    /* MSHUTDOWN */
    NULL,                    /* RINIT  (per-request)     */
    NULL,                    /* RSHUTDOWN */
    PHP_MINFO(hello),        /* phpinfo section */
    "0.1.0",
    STANDARD_MODULE_PROPERTIES
};

#ifdef COMPILE_DL_HELLO
ZEND_GET_MODULE(hello)
#endif

메모리: emalloc과 malloc 비교

/* Request-scoped buffer the engine will clean up on error/shutdown */
char *buf = emalloc(64);
/* ... use buf ... */
efree(buf);

/* Persistent allocation surviving the request (rare) */
/* char *cfg = pemalloc(128, 1);  ...  pefree(cfg, 1); */

빌드하기

# Generate arginfo from the stub
php /path/to/php-src/build/gen_stub.php hello.stub.php

# Scaffold + configure + compile
phpize
./configure --enable-hello
make

# Result lands in modules/hello.so
ls -la modules/hello.so

로드 및 테스트

<?php
// After:  php -d extension=./modules/hello.so test.php
if (!extension_loaded('hello')) {
    fwrite(STDERR, "hello extension not loaded\n");
    exit(1);
}

echo hello_greet('Zend') . PHP_EOL;   // Hello, Zend!
var_dump(extension_loaded('hello'));  // bool(true)
?>

작성할 때와 작성하지 말아야 할 때

<?php
// FFI alternative: call a C library directly, no extension build
$ffi = FFI::cdef(
    "int abs(int);",   // declare the symbol
    "libc.so.6"
);
echo $ffi->abs(-42) . PHP_EOL;   // 42
?>

빠른 확인

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