gdb将评估的原始结果传递给自定义的python函数 [英] gdb pass raw result of evaluation to custom python function

问题描述

amd64，寄存器 $ rdi 是指向/ home / il / gammu-git / src / gammu / libgammu / tls / x86_64的指针/libpthread.so.0

这里看一个例子：

  define foo 
 py print gdb.execute（output $ arg0，to_string = True）.strip（'''）
 end 
  
 
 
 
 $ b $ p $（$） foo（char *）$ rdi 
 /home/il/gammu-git/src/gammu/libgammu/tls/x86_64/libpthread.so.0 
  

但是，输出命令也会输出字符串的地址：

 （gdb）foo（char *）$ rdi 
 0x7fffffffe180/ home / il / gammu-git / src / gammu / libgammu / tls / x86_64 / libpthread .so.0 
  

解决方案

gdb语法是一团糟，而不是MS-DOS的命令行。

使用6个简单步骤，您可以将任意字符串传递给python：

  define foo 
＃重置便利性变量，或者得到'To o许多数组元素'
 set $ foo_arg0 = 0 
＃$ arg0扩展得太早，无法直接在python中使用
 set $ foo_arg0 = $ arg0 
＃
＃parse_and_eval（）受打印设置的影响，wtf？ 
＃
＃不显示字符串的地址
 set print addr off 
＃print long string 
设置打印元素0 
＃删除'<重复n次>'
 set print repeats unlimited 
＃
＃parse_and_eval（）返回带引号的字符串。用eval取消引用
 py s = eval（str（gdb.parse_and_eval（$ foo_arg0）））
 py print s 
 end 
 
（gdb）foo abc
 abc 
（gdb）foo $ val 
 def 
（gdb）foo（char *）$ rdi 
 / home / il / gammu-git / src /gammu/libgammu/tls/x86_64/libpthread.so.0 
  

amd64, register $rdi is a pointer to "/home/il/gammu-git/src/gammu/libgammu/tls/x86_64/libpthread.so.0"

Seen here an example:

define foo
py print gdb.execute("output $arg0", to_string=True).strip('"')
end

expected:

(gdb) foo (char*)$rdi
/home/il/gammu-git/src/gammu/libgammu/tls/x86_64/libpthread.so.0

However, the output command also prints the address of the string:

(gdb) foo (char*)$rdi
0x7fffffffe180 "/home/il/gammu-git/src/gammu/libgammu/tls/x86_64/libpthread.so.0

解决方案

gdb syntax is a mess, worse than the command line of MS-DOS.

With 6 "simple" steps you can pass arbitrary string to python:

define foo
    # reset convenience var., or get 'Too many array elements'
    set $foo_arg0 = 0
    # $arg0 expanded too early, can't use it directly in python
    set $foo_arg0 = $arg0
    #
    # parse_and_eval() affected by print settings, wtf?
    #
    # don't print address of a string
    set print addr off
    # print long string
    set print elements 0
    # get rid of '<repeats n times>'
    set print repeats unlimited
    #
    # parse_and_eval() returns quoted string. Unquote with eval
    py s = eval(str(gdb.parse_and_eval("$foo_arg0")))
    py print s
end

(gdb) foo "abc"
abc
(gdb) foo $val
def
(gdb) foo (char*)$rdi
/home/il/gammu-git/src/gammu/libgammu/tls/x86_64/libpthread.so.0

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