如何运行时调试共享库？ [英] How to runtime debug shared libraries?

问题描述

任何人都可以告诉我如何在共享库上执行运行时调试？

Can anyone tell me how to do runtime debugging on shared libraries?

我需要在我的共享库中运行时调试一个函数，但是由另一个程序调用。
我如何使用共享库来执行类似dbx的东西？

I need to runtime-debug a function in my shared library, but its called by another program. How can I do something like dbx with shared libraries?

我在AIX上使用dbx。
是比dbx更好的我想要做什么？

I m using dbx on AIX. is gdb better than dbx for what I m trying to do?.

推荐答案

你只需要调用gdb可执行文件（如果是您的第三方，则无关紧要）。以下是一个示例，其中我调试了 ls 命令并在（共享）c库中设置断点。此示例使用支持延迟（挂起）断点的gdb 6.8，这使得这很容易：

You just need to call gdb with the executable (it does not matter if it is yours or a 3rd party one). Here is an example where I debug the ls command and set a breakpoint in the (shared) c library. This example uses gdb 6.8 which supports deferred (pending) breakpoints which makes this easy:

gdb /bin/ls
GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu"...
(no debugging symbols found)
(gdb) b write
Function "write" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (write) pending.
(gdb) r
Starting program: /bin/ls
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
(no debugging symbols found)
(no debugging symbols found)
[New Thread 0x7f98d2d23780 (LWP 7029)]
[Switching to Thread 0x7f98d2d23780 (LWP 7029)]

Breakpoint 1, 0x00007f98d2264bb0 in write () from /lib/libc.so.6
(gdb)

可以看到gdb自动管理可执行文件使用的所有线程。你不需要为线程做任何特别的事情。断点将在任何线程中工作。

As you can see gdb automatically manages all threads used by the executable. You don't have to do anything special for threads there. The breakpoint will work in any thread.

或者，如果要将调试器附加到已运行的应用程序（我使用 tail -f / tmp / ttt 这里作为示例）：

Alternatively if you want to attach the debugger to an already running application (I use tail -f /tmp/ttt here as an example):

ps ux | grep tail
lothar    8496  0.0  0.0   9352   804 pts/3    S+   12:38   0:00 tail -f /tmp/ttt
lothar    8510  0.0  0.0   5164   840 pts/4    S+   12:39   0:00 grep tail

gdb
GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu"...
(no debugging symbols found)
(gdb) attach 8496
Attaching to program: /usr/bin/tail, process 8496
Reading symbols from /lib/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/librt.so.1
Reading symbols from /lib/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
[New Thread 0x7f24853f56e0 (LWP 8496)]
Loaded symbols for /lib/libpthread.so.0
Reading symbols from /lib/ld-linux-x86-64.so.2...
(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
(no debugging symbols found)
0x00007f2484d2bb50 in nanosleep () from /lib/libc.so.6
(gdb) b write
Breakpoint 1 at 0x7f2484d57bb0
(gdb) c
Continuing.
[Switching to Thread 0x7f24853f56e0 (LWP 8496)]

Breakpoint 1, 0x00007f2484d57bb0 in write () from /lib/libc.so.6
(gdb)

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