[Adium-devl] Let's abandon disk images

[Graham Booker]

On Mar 31, 2007, at 6:29 PM, Peter Hosey wrote:

> On Mar 31, 2007, at 14:38:37, Ofri Wolfus wrote:
>> 2. fork/exec.
>
> There are two problems with this:
> 1. If the child process (ostensibly `diskutil eject` or something)  
> tries to do the eject before its parent has exited, the parent's  
> executable file and probably various resources are still in use, so  
> the eject will fail.
> 2. Whenever the parent process exits, it will take the child  
> process with it.
>
> Problem 2 can be solved by using ptrace to detach from the child (I  
> think—I've never tried). Alternatively, using signal(2) to block  
> SIGHUP may work.
>

Nope, not a problem.  Example file:

#include <sys/types.h>
#include <unistd.h>

extern char **environ;

int main(int argc, char *argv[])
{
	char *args[] = {"/bin/sh", "-c", "sleep 5; sleep 5; sleep 5", NULL};
	int forkVal = fork();
	if(forkVal == 0)
		execve("/bin/sh", args, environ);
}


Watch top (with no args).  You will see sleep show up with three  
different proccess ID's 5 seconds apart.  Exactly what we want.   
Note, the original a.out exited during this process.  Exactly what we  
wanted.

> Problem 1 can be solved by using a shell script, which you could  
> pass to exec:
>
> 	static const char eject_argv[][] = {
> 		"bash", "-c",
> 		/*Something like the script Graham suggested*/,
> 		NULL
> 	};
> 	pid_t pid = execvp("bash", eject_argv);
>
> ___________________________________
> \ Peter Hosey / boredzo at adiumx.com
> PGP public key ID: C6550423 (since 2007-01-01)


:), yep, what I do here.	 :P


- Graham