Step-by-step instructions for debugging Cisco IOS using gdb

["Smiler S" <smiler808 () googlemail com>]

 From: Andy Davis
<iosftpexploit_at_googlemail.com<iosftpexploit_at_googlemail.com?Subject=Re:%20Step-by-step%20instructions%20for%20debugging%20Cisco%20IOS%20using%20gdb>>

Date: Tue, 12 Aug 2008 22:01:37 +0100

> Congratulations you are now debugging IOS ;-)
> One unusual feature, which I have yet to explain is that when the
> registers are displayed they are all offset by 1 e.g:

If a vector variable is stored in a register, gcc writes debug information
telling gdb which register the variable is stored in. This mapping is
changed between gcc2 & gcc3. Since there isn't anything in the debug output
to distinguish code compiled by gcc3 from code compiled by gcc2, there is no
way for gdb to know the right map. gdb supports the gcc3 map.

If vector code is compiled by gcc2 as in the case of IOS, then the register
assignment will be off by 1.

PS  - Stop ripping Gyan and Varuns IOS research work you jackass cause you
ain't getting no fame with that bullshit :P :P :P

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