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clinuxexecatexit

Execv register issue at atexit()

"No functions registered by atexit() in the calling process image are registered in the new process image".

Here is code:

pid = fork();
if (pid == 0) {
    atexit(check_mem);
    return execv(...);
}

check_mem function not getting called after execv(). Because of above "line". Any hacks to get the function registered after execv call ??

Thanks in advance for your help.

Solution

  • The perfect solution is using ptrace() as below :

    pid = fork();
if (pid == 0) {
    ptrace(PTRACE_TRACEME, 0, 0, 0);
    return execve(...);
}

wait(NULL);
ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACEEXIT);
ptrace(PTRACE_CONT, pid, 0, (void*)0);

    while(1){
    waitpid(pid, &status, 0);
    if((WSTOPSIG(status) == SIGTRAP) && (status & (PTRACE_EVENT_EXIT << 8)))
        break;

    ptrace(PTRACE_CONT, pid, 0, WSTOPSIG(status));
}

check_mem();

ptrace(PTRACE_CONT, pid, 0, 0);

    Acknowledgments : www.wienand.org/junkcode/linux/stopper.c