Change Owner of a Currently Running Process

Change owner of a currently running process

You cannot do that, there's no such syscall. However, depending on how you want to affect the process, you could try some hack if the process is not critical to your system.

(gdb) attach process_id
(gdb) call putenv ("UID=1234")
(gdb) call putenv ("EUID=1234")
(gdb) call putenv ("GID=1234")
(gdb) detach

Note that this WILL NOT WORK:

(gdb) call setuid(1234)

This does not really answer to your question (change the owner of a running process), but considering that you may want to change the owner to affect something about the process, maybe this hack help.

Remember that it's very likely that this breaks your process.

(based on this:
Is there a way to change another process's environment variables?)

Changing the owner of an existing process in Linux

I am aware of kchuid which does exactly that, and although it appears abandoned, it doesn't look like it would be hard to bring up-to-date.

That said, the hosting company I work for does allow (on the shared hosting packages) users to run their own webserver- including Tomcat- on port 80. This is done using a tool called authbind which doesn't require the server start as root- but simply lets non-root users bind to selected IP addresses and selected ports.

The only catch is that authbind won't work with Java's network abstraction layer by default. You will need to disable Java's IPV6 support, and probably specify a specific IP address to bind to within your application. The former can be done by starting the JRE with -Djava.net.preferIPv4Stack=true but the latter is application-specific.

change user owner of process on Mac/Linux?

Well it's a little bit tricky... Depends if it's a daemon (service) or you run this command/app.

For the 2nd case you can use "su" command.
Here's a short example.

1. I create o simple script with following content (it will sleep in background for 100 seconds and will output the process list coresponding to this script):

#!/bin/bash
sleep 100 &
ps faux | grep test.sh

2. I run the "su" command like this (I'm currently logged in as "root" and I want to run this script as "sandbox" user):

su - sandbox -c ./test.sh

sandbox = the username that will run this command.
-c ./test.sh = means it will execute this command

3. Output (first column = the user that owns this process):

root@i6:/web-storage/sandbox# su - sandbox -c ./test.sh
sandbox  18149  0.0  0.0  31284  1196 pts/0    S+   20:13   0:00                      \_ su - sandbox -c ./test.sh
sandbox  18150  0.0  0.0   8944  1160 pts/0    S+   20:13   0:00                          \_ /bin/bash ./test.sh
sandbox  18155  0.0  0.0   3956   644 pts/0    S+   20:13   0:00                              \_ grep test.sh
root@i6:/web-storage/sandbox#

I hope it will help,
Stefan

Changing user process on a system process

You can not change users a process is running under, you may be able to do impersonation to run a section of code as another user, but you can not modify the process itself to be running as another user.

To make your process run as SYSTEM it must be started under that user.

How to change the terminal title to currently running process?

UPDATE: my previous answer (below) displays the previous command in the title bar.

Ignoring everything from my previous answer and starting from scratch:

trap 'echo -ne "\033]0;${PWD}: (${BASH_COMMAND})\007"' DEBUG

Running the following at the command prompt:

$ sleep 10

The window title bar changes to /my/current/directory: (sleep 10) while the sleep 10 is running.

Running either of these:

$ sleep 1; sleep 2; sleep 3
$ { sleep 1; sleep2; sleep 3; }

The title bar changes as each sleep command is invoked.

Running this:

$ ( sleep 1; sleep 2; sleep 3 )

The title bar does not change (the trap does not apply within a subprocess call).

One last one:

$ echo $(sleep 3; echo abc)

The title bar displays (echo $sleep 3; echo abc)).

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previous answer

Adding to this answer:

store_command() {
  declare -g last_command current_command
  last_command=$current_command
  current_command=$BASH_COMMAND
  return 0
}
trap store_command DEBUG

PROMPT_COMMAND='echo -ne "\033]0;${PWD}: (${last_command})\007"'

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Additional reading materials re: trap / DEBUG:

• bash guide on traps
• SO Q&A

PHP - changing ownership of a process while running

You can change user/group ids with the following functions:

posix_setgid

posix_setuid

posix_setegid

posix_seteuid

If you need to change the group, you'll want to perform that first.

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