execve：将execve调用转换为fork

Question

I have an execve system call to overlay my curernt program with another one. The code works fine but I my requirement is to change this execve system call with fork system call. I am trying something like below:

pid_t child_pid;
child_pid = fork();
if(child_pid == 0) {
       if (-1 == execve(...)) //Normal previous execve call
       {
          .............
       }
}
else
{ //fork parent process
exit(0);
}

I am not sure that when we are replacing an execve system call by fork what things we should take care. In my child process I am calling the existing execve call to let the original flow be maintained (as if without fork) but what should the parent do - should I normally exit or I need to wait for the child process to exit/die. The execve call overlays the current process with a new one so there is no question of parent / child process.

Answer 1

That's up to you. If you don't need to wait around, then you can just exit in which case the child process will become orphaned.

Answer 2

If the exit status of the child needs to be known, or if there is some operation to be performed after the child process exits, call wait() in the parent.

If there is no need for either of the above, you can exit the parent process. The orphaned process will be re-parented by init , and hence will have no adverse effects.

Answer 3

 should I normally exit or I need to wait for the child process to exit/die

It depends on you, and your requirements, if needed you can wait for child process using wait(...), have a look at http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=%2Fapis%2Fwait.htm

Also have a look at http://linux.die.net/man/2/fork