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Diffstat (limited to 'src/gdb.md')
| -rw-r--r-- | src/gdb.md | 49 |
1 files changed, 29 insertions, 20 deletions
@@ -72,6 +72,7 @@ # User commands (macros) +Gdb allows to create & document user commands as follows: ```markdown define <cmd> # cmds @@ -80,29 +81,34 @@ document <cmd> # docu end +``` - help user-defined List user defined commands. - help <cmd> List documentation for command <cmd>. +To get all user commands or documentations one can use: +```markdown + help user-defined + help <cmd> ``` # Hooks -Gdb allows to create two types of command `hooks` which will be either executed -before or after a certain command. - +Gdb allows to create two types of command `hooks` +- `hook-` will be run before `<cmd>` +- `hookpost-` will be run after `<cmd>` ```markdown - define hook-<cmd> Run commands defined in hook before - # cmds executing <cmd>. + define hook-<cmd> + # cmds end - define hookpost-<cmd> Run commands defined in hookpost after - # cmds executing <cmd>. + define hookpost-<cmd> + # cmds end ``` -# Flows +# Examples -## Catch SIGSEGV and execute commands on occurrence +## Catch SIGSEGV and execute commands +This creates a `catchpoint` for the `SIGSEGV` signal and attached the `command` +to it. ```markdown catch signal SIGSEGV command @@ -117,8 +123,9 @@ before or after a certain command. ``` ## Script gdb for automating debugging sessions +To script gdb add commands into a file and pass it to gdb via `-x`. +For example create `run.gdb`: ```markdown -# run.gdb set pagination off break mmap @@ -133,21 +140,23 @@ before or after a certain command. ``` This script can be used as: ```markdown - gdb -p <pid> -x ./run.gdb --batch &> run.log + gdb --batch -x ./run.gdb -p <pid> ``` +# Know Bugs + ## Workaround `command + finish` bug -When using `finish` action inside a `command` block, actions after `finish` are -not executed anymore. To workaround that bug one can create a wrapper function -which calls `finish`. +When using `finish` inside a `command` block, commands after `finish` are not +executed. To workaround that bug one can create a wrapper function which calls +`finish`. ```markdown define handler - bt - finish - info reg rax + bt + finish + info reg rax end command - handler + handler end ``` |