14: Returning to User Space

pravjot

14: Returning to User Space

Explain the final steps of the `execve()` system call as the process returns to user space. What happens if there is an error during the execution of `execve()`?

gaurav133232

On returning to execve the following steps happen:-

The CPU registers and stack are set for the new executable.
Control switches back to the user mode and the command specified is executed.

If
execve fails, it returns -1 with the errno specifying what kind of
error occured, this can be checked using an error handler for e.g

int ret = execve("/bin/ls",argv,envp);

if(ret == -1)

{

perror("execl failed");

}

Here perror will do the error handling.

14: Returning to User Space

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