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如何使用PHP Embed SAPI实现Opcodes查看器

更新时间:2020-03-06 14:56:17 作者:startmvc
PHP提供了一个EmbedSAPI,也就是说,PHP容许你在C/C++语言中调用PHP/ZE提供的函数。本文就通过

PHP提供了一个Embed SAPI,也就是说,PHP容许你在C/C++语言中调用PHP/ZE提供的函数。本文就通过基于Embed SAPI实现一个PHP的opcodes查看器。

首先,下载PHP源码以供编译, 我现在使用的是PHP5.3 alpha2

进入源码目录:

 ./configure --enable-embed --with-config-file-scan-dir=/etc/php.d --with-mysql  --with-config-file-path=/etc/  ./make  ./make install

最后,记得要将生成的libphp5.so复制到运行时库的目录,我直接拷贝到了/lib/, 否则会在运行你自己的embed程序的时候报错:

./embed: error while loading shared libraries: libphp5.so: cannot open shared object file: No such file or directory

如果你对PHP的SAPI还不熟悉的话,我建议你看看我的这篇文章:深入理解Zend SAPIs(Zend SAPI Internals) 这个时候,你就可以在你的C代码中,嵌入PHP脚本解析器了, 我的例子:


#include "sapi/embed/php_embed.h"
int main(int argc, char * argv[]){
 PHP_EMBED_START_BLOCK(argc,argv);
 char * script = " print 'Hello World!';";
 zend_eval_string(script, NULL,
 "Simple Hello World App" TSRMLS_CC);
 PHP_EMBED_END_BLOCK();
 return 0;
}

然后就是要指明include path了,一个简单的Makefile


CC = gcc
CFLAGS = -I/usr/local/include/php/ \
 -I/usr/local/include/php/main \
 -I/usr/local/include/php/Zend \
 -I/usr/local/include/php/TSRM \
 -Wall -g
LDFLAGS = -lstdc++ -L/usr/local/lib -lphp5
ALL:
 $(CC) -o embed embed.cpp $(CFLAGS) $(LDFLAGS)

编译成功以后, 运行,我们可以看到, stdout输出 Hello World!

基于这个,我们就可以很容易的实现一个类似于vld的Opcodes dumper: 首先我们定义opcode的转换函数(全部的opcodes可以查看Zend/zend_vm_opcodes.h);


char *opname(zend_uchar opcode){
 switch(opcode) {
 case ZEND_NOP: return "ZEND_NOP"; break;
 case ZEND_ADD: return "ZEND_ADD"; break;
 case ZEND_SUB: return "ZEND_SUB"; break;
 case ZEND_MUL: return "ZEND_MUL"; break;
 case ZEND_DIV: return "ZEND_DIV"; break;
 case ZEND_MOD: return "ZEND_MOD"; break;
 case ZEND_SL: return "ZEND_SL"; break;
 case ZEND_SR: return "ZEND_SR"; break;
 case ZEND_CONCAT: return "ZEND_CONCAT"; break;
 case ZEND_BW_OR: return "ZEND_BW_OR"; break;
 case ZEND_BW_AND: return "ZEND_BW_AND"; break;
 case ZEND_BW_XOR: return "ZEND_BW_XOR"; break;
 case ZEND_BW_NOT: return "ZEND_BW_NOT"; break;
 /*...省略 ....*/
 default : return "UNKNOW"; break;

然后定义zval和znode的输出函数:


 char *format_zval(zval *z)
{
 static char buffer[BUFFER_LEN];
 int len;
 switch(z->type) {
 case IS_NULL:
 return "NULL";
 case IS_LONG:
 case IS_BOOL:
 snprintf(buffer, BUFFER_LEN, "%d", z->value.lval);
 return buffer;
 case IS_DOUBLE:
 snprintf(buffer, BUFFER_LEN, "%f", z->value.dval);
 return buffer;
 case IS_STRING:
 snprintf(buffer, BUFFER_LEN, "\"%s\"", z->value.str.val);
 return buffer;
 case IS_ARRAY:
 case IS_OBJECT:
 case IS_RESOURCE:
 case IS_CONSTANT:
 case IS_CONSTANT_ARRAY:
 return "";
 default:
 return "unknown";
 }
}
char * format_znode(znode *n){
 static char buffer[BUFFER_LEN];
 switch (n->op_type) {
 case IS_CONST:
 return format_zval(&n->u.constant);
 break;
 case IS_VAR:
 snprintf(buffer, BUFFER_LEN, "$%d", n->u.var/sizeof(temp_variable));
 return buffer;
 break;
 case IS_TMP_VAR:
 snprintf(buffer, BUFFER_LEN, "~%d", n->u.var/sizeof(temp_variable));
 return buffer;
 break;
 default:
 return "";
 break;
 }
}

 然后定义op_array的输出函数:


void dump_op(zend_op *op, int num){
 printf("%5d %5d %30s %040s %040s %040s\n", num, op->lineno,
 opname(op->opcode),
 format_znode(&op->op1),
 format_znode(&op->op2),
 format_znode(&op->result)) ;
}
void dump_op_array(zend_op_array *op_array){
 if(op_array) {
 int i;
 printf("%5s %5s %30s %040s %040s %040s\n", "opnum", "line", "opcode", "op1", "op2", "result");
 for(i = 0; i < op_array->last; i++) {
 dump_op(&op_array->opcodes[i], i);
 }
 }
}

最后,就是程序的主函数了:


int main(int argc, char **argv){
 zend_op_array *op_array;
 zend_file_handle file_handle;
 if(argc != 2) {
 printf("usage: op_dumper <script>\n");
 return 1;
 }
 PHP_EMBED_START_BLOCK(argc,argv);
 printf("Script: %s\n", argv[1]);
 file_handle.filename = argv[1];
 file_handle.free_filename = 0;
 file_handle.type = ZEND_HANDLE_FILENAME;
 file_handle.opened_path = NULL;
 op_array = zend_compile_file(&file_handle, ZEND_INCLUDE TSRMLS_CC);
 if(!op_array) {
 printf("Error parsing script: %s\n", file_handle.filename);
 return 1;
 }
 dump_op_array(op_array);
 PHP_EMBED_END_BLOCK();
 return 0;
}

编译,运行测试脚本(sample.php):


sample.php:
   echo "laruence";

命令:


./opcodes_dumper  sample.php

得到输出结果(如果你对下面的结果很迷惑,那么建议你再看看我的这篇文章:深入理解PHP原理之Opcodes):

Script: sample.php

opnum   line                         opcode                                      op1                                      op2                                   result     0      2                      ZEND_ECHO                               "laruence"     1      4                    ZEND_RETURN                                        1

呵呵,怎么样,是不是很好玩呢?

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