Changing the main program name at runtime

[simran]

Hi All, 

I was going through "Go by Example" and on https://gobyexample.com/command-line-arguments - it talks about os.Args. 

I've found that i can change os.Args[0] in my program (which makes sense, it's just a slice of strings i guess), but that does not change the program name being executed. 

That is, doing a "ps auxww | grep <progname>" shows me the original program name i executed, even though i changed os.Args[0]. 

Is it possible to change the name of the program being executed at runtime? 

kind regards, 

simran.

ps: Coming from perl where changing $0 actually changes the running program name (*for the most part - see http://perldoc.perl.org/perlvar.html and search for $0). 

[Dave Cheney]

os,Args is a copy of the program environment which is made very early on in the life of the process. I don't know how perl works, but I suspect they have additional magic to make those changes visible to other programs.

[Micky]

Looking at the perlvar docs, I can see it's modified by prctl() syscall. So, you can directly use its PR_SET_NAME argument.

All you need to know is how to use to the "unsafe" package.

If that's too complicated, a workaround is spawning a new process. See os.StartProcess.

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[Staven]

On Mon, Oct 05, 2015 at 02:22:42PM +1100, simran wrote:
> Is it possible to change the name of the program being executed at runtime?

Out of curiosity, why would you want to do something like that?

[simran]

Hi Staven, 

I'm sure there's heaps of reasons, but i was coming from the perspective of looking at rootkits, etc... and they hide their process names - make it look like it's an innocent window manager process or something like that is running. I know it doesn't ultimate disguise the process but it can throw people off on a visual inspection via ps... it's just another layer. 

The reason perl mentioned in some perl documentation is that you can send other processes outside it an update on which stage your process is at (just via the system process table).

cheers, 

simran.

ps: Dave, Micky, thanks for your responses... good info in both of them and i'm digging further as a result :) 

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[Nathan Fisher]

I'm not saying it's a good use case but if you use dynamic port allocation you could append the allocated port to the process name to make listening port, process id, and start time all visible from a ps listing on the command line.

[Manlio Perillo]

Both Nginx and PostgreSQL use this feature, to make it easy to search for a specific process.

As an example:

root       456  0.0  0.0  25812   760 ?        Ss   Sep29   0:00 nginx: master process /usr/bin/nginx -g pid /run/nginx.pid; error_log stderr;

http       457  0.0  0.0  26264  1624 ?        S    Sep29   0:00 nginx: worker process

Regards  Manlio

[Dave Cheney]

Add prctl support to x/SYS would be a useful project to get your feet wet in Go development.

[Erik Dubbelboer]

Try https://github.com/ErikDubbelboer/gspt

[simran]

Thanks Erik, 

Works a charm :) 

cheers, 

simran.

On Wed, Oct 7, 2015 at 2:03 AM, Erik Dubbelboer <er...@dubbelboer.com> wrote:

Try https://github.com/ErikDubbelboer/gspt

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[Dave Cheney]

See https://go-review.googlesource.com/#/c/15520/

On Wednesday, 7 October 2015 04:32:32 UTC+11, Erik Dubbelboer wrote:

Try https://github.com/ErikDubbelboer/gspt