GDB needs root?

[GeekOfSpades]

I'm having some trouble with running GDB as non-root.

Given an executable /home/hawkeye/c/tx/tx compiled with -ggdb3 -Wall -pipe

% ls -l /home/hawkeye/c/tx/tx
-rwxr-xr-x 1 hawkeye users 702042 Jul 16 00:01 my_exe

% gdb /home/hawkeye/c/tx/tx
* SNIP GDB OUTPUT *
(gdb) run
Starting program: /home/hawkeye/c/tx/tx
Cannot exec : No such file or directory.

Program exited with code 0177.
You can't do that without a process to debug.
(gdb)

Now when root attempts the same thing, gdb runs with no complaints. Even chmod a+s /usr/bin/gdb doesn't do the trick?

Can anybody provide any insight? (gdb was compiled with -O2 -pipe, but I don't see how that could affect it...)

Thanks

[Naan Yaar]

gdb does not like its sticky bit changed. You need to do "chmod a-s..." first. The "You can't do that without a process to debug" error is because of the sticky bit.

The exec error may come from an "execv." or "execl." function call in the program itself that tries to launch an executable that it cannot "find".

[GeekOfSpades]

Removing the stick bit didn't change the error message at all. In regards the exec* call, under what circumstances do you think root would be able to run a program, whereas a normal user would be unable to even locate the file?

I might guess that it's a permission problem. IE, gdb doesn't have access to the file, therefore can not find it. I'd assume though gdb would be more forthcoming with that information (a la "Permission Denied") On top of that, the permissions seem quite fine. My non-root self has no problem cd'ing into the directory and running the executable. Or any executable on the system for that matter.

I must say this has me confounded...

[Naan Yaar]

I tried gdb on a simple program just to make sure things are OK. On my box, there are no problems. Re: exec*: you may not have permissions to the read the file, list files in the directory, execute permissions to the file, etc. If you see something like:
-rwxr-xr-- root root ...
for the directory permissions, you will not be able to list files in the directory nor run them. You can do "chmod ..." to ensure that the files and/or directory have right permissions.

Try compiling a simple hello.c in the user directory and then see whether you can debug it.

[GeekOfSpades]

Permissions don't seem to be the problem... observe...

[AstroBoy]

The same problem is described here: https://forums.gentoo.org/viewtopic.php?t=9857&highlight=gdb+cannot+run
They solved it with setting $SHELL. It even worked for me.