PHP提供了一個Embed SAPI，也就是說，PHP容許你在C/C++語言中調用PHP/ZE提供的函數。本文就通過基於Embed SAPI實現一個PHP的opcodes查看器。
首先，下載PHP源碼以供編譯， 我現在使用的是PHP5.3 alpha2
進入源碼目錄：
./configure --enable-embed --with-config-file-scan-dir=/etc/php.d --with-mysql --with-config-file-path=/etc/
./make
./make install
最後，記得要將生成的libphp5.so復制到運行時庫的目錄，我直接拷貝到了/lib/, 否則會在運行你自己的embed程序的時候報錯：
./embed: error while loading shared libraries: libphp5.so: cannot open shared object file: No such file or directory
如果你對PHP的SAPI還不熟悉的話，我建議你看看我的這篇文章：深入理解Zend SAPIs(Zend SAPI Internals)
這個時候，你就可以在你的C代碼中，嵌入PHP腳本解析器了， 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;
}
然後就是要指明include path了，一個簡單的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) $(LDFLAGS)
編譯成功以後， 運行，我們可以看到， stdout輸出 Hello World！
基於這個，我們就可以很容易的實現一個類似於vld的Opcodes dumper：
首先我們定義opcode的轉換函數（全部的opcodes可以查看Zend/zend_vm_opcodes.h）；
char *opname(zend_uchar opcode){
switch(opcode) {
case ZEND_NOP: return "ZEND_NOP"; break;
case ZEND_ADD: return "ZEND_ADD"; break;
case ZEND_SUB: return "ZEND_SUB"; break;
case ZEND_MUL: return "ZEND_MUL"; break;
case ZEND_DIV: return "ZEND_DIV"; break;
case ZEND_MOD: return "ZEND_MOD"; break;
case ZEND_SL: return "ZEND_SL"; break;
case ZEND_SR: return "ZEND_SR"; break;
case ZEND_CONCAT: return "ZEND_CONCAT"; break;
case ZEND_BW_OR: return "ZEND_BW_OR"; break;
case ZEND_BW_AND: return "ZEND_BW_AND"; break;
case ZEND_BW_XOR: return "ZEND_BW_XOR"; break;
case ZEND_BW_NOT: return "ZEND_BW_NOT"; break;
/*...省略 ....*/
default : return "UNKNOW"; break;
然後定義zval和znode的輸出函數：
char *format_zval(zval *z)
{
static char buffer[BUFFER_LEN];
int len;
switch(z->type) {
case IS_NULL:
return "NULL";
case IS_LONG:
case IS_BOOL:
snprintf(buffer, BUFFER_LEN, "%d", z->value.lval);
return buffer;
case IS_DOUBLE:
snprintf(buffer, BUFFER_LEN, "%f", z->value.dval);
return buffer;
case IS_STRING:
snprintf(buffer, BUFFER_LEN, "\"%s\"", z->value.str.val);
return buffer;
case IS_ARRAY:
case IS_OBJECT:
case IS_RESOURCE:
case IS_CONSTANT:
case IS_CONSTANT_ARRAY:
return "";
default:
return "unknown";
}
}
char * format_znode(znode *n){
static char buffer[BUFFER_LEN];
switch (n->op_type) {
case IS_CONST:
return format_zval(&n->u.constant);
break;
case IS_VAR:
snprintf(buffer, BUFFER_LEN, "$%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;
}
}
然後定義op_array的輸出函數：
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);
}
}
}
最後，就是程序的主函數了：
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;
}
編譯，運行測試腳本(sample.php):
復制代碼 代碼如下:
sample.php:
echo "laruence";
命令：
復制代碼 代碼如下:
./opcodes_dumper sample.php
得到輸出結果(如果你對下面的結果很迷惑，那麼建議你再看看我的這篇文章：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，怎麼樣，是不是很好玩呢？
