GitHub - hq6/GdbShellPipe: Enable piping of internal command output to external...

README.md

Shell-Pipe Command

This gdb extension allows the piping of internal gdb commands to external commands, as described in this Stackoverflow question.

Suppose one wanted to find all the mov instructions in the current function.

(gdb) disas
Dump of assembler code for function foo:
0x0000000000400526 <+0>:     push   %rbp
0x0000000000400527 <+1>:     mov    %rsp,%rbp
0x000000000040052a <+4>:     sub    $0x10,%rsp
0x000000000040052e <+8>:     movq   $0x4005e4,-0x8(%rbp)
=> 0x0000000000400536 <+16>:    mov    -0x8(%rbp),%rax
0x000000000040053a <+20>:    mov    %rax,%rdi
0x000000000040053d <+23>:    callq  0x400400 <puts@plt>
0x0000000000400542 <+28>:    nop
0x0000000000400543 <+29>:    leaveq
0x0000000000400544 <+30>:    retq

One can source the file ShellPipeCommand.py in their $HOME/.gdb_init file, and then invoke the following command.

    (gdb) shell-pipe disas | grep mov
    0x0000000000400527 <+1>:     mov    %rsp,%rbp
    0x000000000040052e <+8>:     movq   $0x4005e4,-0x8(%rbp)
 => 0x0000000000400536 <+16>:    mov    -0x8(%rbp),%rax
    0x000000000040053a <+20>:    mov    %rax,%rdi

Note that the native gdb shell command already handles shell pipelines which do not involve internal gdb commands. This extension is intended for the case where the first command in the pipeline is a gdb internal command. If the first command in the pipeline is a valid gdb command as well as a valid external command, it will be interpreted as the former rather than the latter.