test.php为纯文字:
<?php
$x = "a";
echo $x;
test.php as opcode:
debian:~ php -d vld.active=1 -d vld.execute=0 -f test.php
Finding entry points
Branch analysis from position: 0
Return found
filename: /root/test.php
function name: (null)
number of ops: 5
compiled vars: !0 = $x
line # * op fetch ext return operands
---------------------------------------------------------------------------------
2 0 > EXT_STMT
1 ASSIGN !0, 'a'
3 2 EXT_STMT
3 ECHO !0
4 4 > RETURN 1
branch: # 0; line: 2- 4; sop: 0; eop: 4
path #1: 0,
test.php作为二进制表示:
debian:~ php -d apc.stat=0 -r "
require '/root/test.php';
echo PHP_EOL;
echo chunk_split(bin2hex(
apc_bin_dump(array('/root/test.php'))
),64);
"
(跳过test.php的echo-output)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[ ... a lot of lines just containing 0s ... ]
0000000000000038000000c30000007f0000007a010000830000007c0200008f
0000003c000000400000004400000008
现在我想了解更多关于操作码如何转换为二进制表示的信息。
经过编辑和澄清的问题:
操作码是如何翻译成二进制版本的? 你能看到'a'的ASSIGN来!0? 是否存在ECHO声明及其输出内容?
我发现二进制版本中的一些模式暗示了操作码的逐行表示。
(“2f726f6f742f746573742e706870”是“/root/test.php”的十六进制表示)
修改:
当行长度设置为4个字节并在不同程序之间进行比较时,十六进制表示显示模式。
...
00000002 // 2 seems to be something like the "line number"
00000065 // seems to increase by 1 for every subsequent statement.
00000040 //
06330808 // seems to mark the START of a statement
00000000
00000000
00000000
00000000
00000001 //
00000012 // In a program with three echo statements,
03000007 // this block was present three times. With mild
00000001 // changes that seem to represent the spot where
00000006 // the output-string is located.
00000008 //
00000000
00000000
00000000
00000000
00000000
00000002 // 2 seems to be something like the "line number"
00000028 //
00000020 //
4a330808 // seems to mark the END of a statement
00000000
00000000
00000000
00000000
00000008 // repeating between (echo-)statements
00000000
00000000
00000000
00000000
00000008 // repeating between (echo-)statements
...
但是我对虚拟机如何在这样的水平上工作的知识太弱了,无法真正地分析它并将其链接到C代码。
修改:
答案 0 :(得分:9)
很棒的问题......
UPDATE:操作码由PHP虚拟机(Zend Engine)直接执行。它看起来好像是由./Zend/zend_vm_execute.h中定义的不同处理程序函数执行的。
有关如何执行Zend操作码的更多信息,请参阅the architecture of the Zend Engine。
这些资源可能会有所帮助:
http://php.net/manual/en/internals2.opcodes.list.php
http://www.php.net/manual/en/internals2.opcodes.ops.php
另外,我打算查看PECL VLD来源以获取更多线索......
http://pecl.php.net/package/vld
http://derickrethans.nl/projects.html#vld
此外,撰写VLD Pecl扩展的作者可能会有所帮助: Derick Rethans,Andrei Zmievski或MarcusBörger
他们的电子邮件地址位于扩展程序源中srm_oparray.c的顶部。
更新:找到更多线索
在PHP 5.3.8中,我找到了三个执行操作码的引线:
./Zend/zend_execute.c:1270
ZEND_API void execute_internal
./Zend/zend.c:1214:ZEND_API int zend_execute_scripts(int type TSRMLS_DC, zval **retval, int file_count, ...)
./Zend/zend.c:1236: zend_execute(EG(active_op_array) TSRMLS_CC);
./Zend/zend_vm_gen.php
我找不到zend_execute()的定义,但我猜它可能是用./zend_vm_gen.php生成的
我想我发现了......
./Zend/zend_vm_execute.h:42
ZEND_API void execute(zend_op_array *op_array TSRMLS_DC)
我可能错了,但看起来所有的操作码处理程序都在./Zend/zend_vm_execute.h中定义。
有关“整数加法”操作码的示例,请参阅./Zend/zend_vm_execute.h:2413。
答案 1 :(得分:3)
apc_bin_dump()返回内存中缓存条目的原始表示。
它返回apc_bd_t struct的内容。
此结构是一个apc_bd_entry_t数组,带有一些错误检测校验和。
apc_bd_entry_t包含apc_cache_entry_value_t。
您可以查看apc_bin_dump和apc_bin_load内部函数,了解转储和加载的方式。