Shell Programming and Scripting

Hi Gurus
I have a process that starts as root then changes to nobody.
Its on a headless Arm5 pogoplug, and everything is running as root.
so it cant use mailx, and strangely login to a remote site.

I can get the PID, but I cant find anywhere an example of how to use setuid or set setgid to change the owner of the running process to root, so that if I :-

Code:

[root@Pogopig ~]# ps aux | grep noip2
nobody     262  0.0  0.3   1940   788 ?        Ss   14:31   0:00 /usr/bin/noip2 -c /etc/no-ip2.conf
root       314  0.0  0.3   4588   956 pts/0    S+   14:49   0:00 grep noip2

what I want to get is

Code:

[root@Pogopig ~]# ps aux | grep noip2
root    262  0.0  0.3   1940   788 ?        Ss   14:31   0:00 /usr/bin/noip2 -c /etc/no-ip2.conf
root       314  0.0  0.3   4588   956 pts/0    S+   14:49   0:00 grep noip2

I'm stuck on the syntax for
setuid root > PID of process
can someone help please
TIA
Richard

The setgid and setuid bits work fine, but you must compile the command with -R (well, some option that says find dynamic libs by the compile-time dynamic library full paths, only) or entirely static linked, as the environment is cleared of $PATH and $LD_LIBRARY_PATH when changing IDs. This also tends to mess up all script interpreters, even if your script starts with a good #! line and has execute permissions and immediately resets environment. I would expect it is described in the exec() man pages. Man Page for execvp (opensolaris Section 2) - The UNIX and Linux Forums Man Page for setuid (opensolaris Section 2) - The UNIX and Linux Forums

I understand you start it as root but it switches to nobody by means of setuid() and seteuid() calls.
I think you cannot undo that; there is no setuid that works on other processes, and a change of the user in /proc will fail.

Well, I suppose you could code setuid(0) but how to get permission to re-enter root? I guess if you are still uid root, you should be able to change euid back. Otherwise, you need to exec a setuid executable to get the proc back to root.