On 08/17, Keno Fischer wrote:
>
> In this test case, the last
> group-stop (after PTRACE_INTERRUPT) is delivered with a
> WSTOPSIG(status) of SIGTTIN, which was the signr of the previous group
> stop. From reading the man-page, I would have expected SIGTRAP.
Me too ;)
> Now, I
> understand that if there is another stop pending, PTRACE_INTERRUPT
> will simply piggy-backs off that one, but I don't believe that is
> happening in this case.
Yes, thanks. This is wrong. We need to remove SIGTTIN from jobctl.
The problem, I am not sure when... I'll try to think.
Thanks!
> #include <assert.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <signal.h>
> #include <unistd.h>
> #include <sys/ptrace.h>
> #include <sys/wait.h>
> #include <linux/ptrace.h>
>
> int main() {
> pid_t child, ret;
> int err;
> int status;
> if (0 == (child = fork())) {
> kill(getpid(), SIGSTOP);
> kill(getpid(), SIGSTOP);
> kill(getpid(), SIGTTIN);
> sleep(1000);
> exit(0);
> }
> ret = waitpid(child, &status, WSTOPPED);
> assert(ret == child);
> err = ptrace(PTRACE_SEIZE, child, NULL, NULL);
> assert(err == 0);
> err = ptrace(PTRACE_CONT, child, NULL, NULL);
> assert(err == 0);
> // Should now hit SIGSTOP signal-stop
> ret = waitpid(child, &status, 0);
> assert(ret == child && WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
> err = ptrace(PTRACE_CONT, child, NULL, (void*)SIGSTOP);
> assert(err == 0);
> // Should now hit SIGSTOP group-stop
> ret = waitpid(child, &status, 0);
> assert(ret == child && (status>>16 == PTRACE_EVENT_STOP) &&
> WSTOPSIG(status) == SIGSTOP);
> err = ptrace(PTRACE_CONT, child, NULL, NULL);
> assert(err == 0);
> // Should now hit SIGTTIN signal-stop
> ret = waitpid(child, &status, 0);
> assert(ret == child && WIFSTOPPED(status) && WSTOPSIG(status) == SIGTTIN);
> err = ptrace(PTRACE_CONT, child, NULL, (void*)SIGTTIN);
> assert(err == 0);
> // Should now hit SIGTTIN group-stop
> ret = waitpid(child, &status, 0);
> assert(ret == child && (status>>16 == PTRACE_EVENT_STOP) &&
> WSTOPSIG(status) == SIGTTIN);
> err = ptrace(PTRACE_CONT, child, NULL, NULL);
> assert(err == 0);
> // Now interrupt it
> err = ptrace(PTRACE_INTERRUPT, child, NULL, NULL);
> assert(err == 0);
> // Should now hit interrupt group-stop
> ret = waitpid(child, &status, 0);
> printf("Interrupt group-stop delivered with signal %d\n",
> WSTOPSIG(status));
> assert(ret == child && (status>>16 == PTRACE_EVENT_STOP) &&
> WSTOPSIG(status) == SIGTRAP);
> exit(0);
> }
> ```
