woaidongmao

http://www.laruence.com/2008/09/23/539.html

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 instal

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 director

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.ph

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                                        

呵呵，怎么样，是不是很好玩呢？
源码地址：http://code.google.com/p/opcodesdumper/