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nullpo-head / wsl-distrod

Distrod is a meta-distro for WSL 2 which installs Ubuntu, Arch, Debian, Gentoo, etc. with systemd in a minute for you. Distrod also has built-in auto-start feature on Windows startup and port forwarding ability.
MIT License
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gdb not working with distrod #22

Open alierol opened 2 years ago

alierol commented 2 years ago

When I run a program in gdb I get the following error message:

[Distrod][ERROR] Failed to drop_privilege. Aborting.

If I disable distrod debugging goes fine without any problems.

For the time being I simply disable distrod whenever I have to use gdb however a permanent solution would be greatly appreciated.

nullpo-head commented 2 years ago

Thanks for reporting. Yeah, I didn't think of the situation where Distrod's shell is invoked by the debugger. I'll fix it.

By the way, I appreciate it if you could follow the template from next time for a bug report. This time I was able to guess the cause regardless of the environment, but I can't do that every time.

fredizzimo commented 2 years ago

I created a fix for this in https://github.com/nullpo-head/wsl-distrod/pull/48

fredizzimo commented 2 years ago

It turns out that my fix does not completely fix the issue. While the debugging is somewhat working, for example setting breakpoints before running is not.

I found the reason for that. And an old comment gives some information of why it doesn't work.

/ If STARTUP_WITH_SHELL is set, GDB's "run" will attempts to start up the debugee under a shell. This is in order for argument-expansion to occur. E.g., (gdb) run The "*" gets expanded by the shell into a list of files. While this is a nice feature, it turns out to interact badly with some of the catch-fork/catch-exec features we have added. In particular, if the shell does any fork/exec's before the exec of the target program, that can confuse GDB. To disable this feature, set STARTUP_WITH_SHELL to 0. To enable this feature, set STARTUP_WITH_SHELL to 1. The catch-exec traps expected during start-up will be 1 if target is not started up with a shell, 2 if it is.

I don't think there's an easy for that, but perhaps there's a way to redefine the $SHELL environment variable to the real shell once wsl-distrod is stared.

But there are a few workarounds that users can do.

  1. Add set startup-with-shell off' to either the user or systemgdbinit`
  2. Run the command inside gdb before running the executable
  3. Start gdb with another shell for example SHELL=/bin/bash gdb
  4. Export the real shell in the '.profile`

Note that these workarounds can be applied without the linked pull request.

nullpo-head commented 2 years ago

Hi thanks so much for trying to fix it and the workaround, @fredizzimo !

Yes actually it needs two fixes; one is fix drop privilege, the another is bind-mounting the real shell on /opt/distrod/alias/usr/bin/*sh. I was working on it before getting busy, and now I have time and am resuming the work.

xu-zhipeng commented 2 years ago

Has this problem been fixed now? I need to debug through clion + WSL, but I still report an error. I use distrod version 0.1.4 The error message is: com. jetbrains. cidr. execution. debugger. backend. gdb. GDBDriver$GDBCommandException: Warning: Cannot insert breakpoint 1. Cannot access memory at address 0x1e216

herrwinfried commented 2 years ago

this problem still persists. When will it be resolved?