Attachment 159113 Details for Bug 247971 – exitcode.c source code to demo bug

exitcode.c source code to demo bug

exitcode.c (text/plain), 3.93 KB, created by Tom Horsley on 2007-07-13 01:48:32 UTC

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Creator: Tom Horsley

Created: 2007-07-13 01:48:32 UTC

Size: 3.93 KB

patch

obsolete

>/* Demonstrate that the about to exit status fails to appear when tracking
> * exit via PTRACE_SETOPTIONS.
> */
>#include <stdio.h>
>#include <sys/types.h>
>#include <unistd.h>
>#include <sys/ptrace.h>
>#include <errno.h>
>#include <string.h>
>#include <signal.h>
>#include <stdlib.h>
>#include <sys/wait.h>
>#include <pthread.h>
>
>/* These only seem to appear in kernel source, so just #define them here */
>
>#define PTRACE_SETOPTIONS	((enum __ptrace_request)0x4200)
>#define PTRACE_O_TRACEEXIT	0x00000040
>#define PTRACE_EVENT_EXIT	6
>
>void
>report_error(char * name, char * func) {
>   int errnum = errno;
>   fprintf(stderr, "ERR: %s %s call failed: %s (errno = %d)\n",
>           name, func, strerror(errnum), errnum);
>   fflush(stderr);
>}
>
>void
>fatal_error(char * name, char * func) {
>   report_error(name, func);
>   exit(2);
>}
>
>void *
>twiddle(void * arg) {
>   int i;
>   for (i = 0; i < 1000; ++i) {
>      sleep(1);
>   }
>   return arg;
>}
>
>int
>main() {
>
>   pid_t kid;
>   sigset_t maskoff;
>   int i;
>   pthread_t thr;
>
>   sigemptyset(&maskoff);
>   sigaddset(&maskoff, SIGCHLD);
>   sigaddset(&maskoff, SIGPIPE);
>   sigprocmask(SIG_BLOCK, &maskoff, NULL);
>
>   sigemptyset(&maskoff);
>   sigaddset(&maskoff, SIGUSR1);
>   sigprocmask(SIG_UNBLOCK, &maskoff, NULL);
>
>   kid = fork();
>   if (kid == (pid_t)-1) {
>      fatal_error("exitcode", "fork()");
>   }
>   if (kid == 0) {
>
>      /* In kid say we should be debugged */
>
>      if (ptrace(PTRACE_TRACEME, 0, 0, 0) == -1) {
>         fatal_error("exitcode child", "ptrace(PTRACE_TRACEME)");
>      }
>
>      /* Then send myself a signal which the parent can grab */
>
>      kill(getpid(), SIGUSR1);
>
>      /* complicate things a bit by creatng a thread (only fails if I do this) */
>
>      pthread_create(&thr, NULL, twiddle, (void *)0);
>
>      sleep(1);
>
>      /* Then just exit so parent can trace my about to exit status */
>
>      _exit(0);
>   } else {
>
>      int waitstat;
>
>      /* Wait for the kid to send himself SIGUSR1, set exit option once we
>       * have control.
>       */
>
>      if (waitpid(kid, &waitstat, WUNTRACED|__WALL) != kid) {
>         fatal_error("exitcode parent", "waitpid(kid)");
>      }
>      if (ptrace(PTRACE_SETOPTIONS, kid, 0, PTRACE_O_TRACEEXIT) == -1) {
>         fatal_error("exitcode parent", "ptrace(PTRACE_SETOPTIONS, exit)");
>      }
>
>      /* Now continue kid and wait for the about to exit */
>
>      if (ptrace(PTRACE_CONT, kid, 0, 0) == -1) {
>         fatal_error("exitcode parent", "ptrace(PTRACE_CONT)");
>      }
>      if (waitpid(kid, &waitstat, WUNTRACED|__WALL) != kid) {
>         fatal_error("exitcode parent", "waitpid(kid)");
>      }
>
>      /* what status info did we get? Expecting a SIGTRAP with an
>       * extended code that mentions PTRACE_EVENT_EXIT.
>       */
>
>      printf("waitpid status: 0x%x\n", waitstat);
>      if (WIFSTOPPED(waitstat)) {
>         int sig = WSTOPSIG(waitstat);
>         if (sig == SIGTRAP) {
>            int event_code = (waitstat >> 16) & 0xff;
>            if (event_code == PTRACE_EVENT_EXIT) {
>               printf("PASS: got SIGTRAP with event code PTRACE_EVENT_EXIT\n");
>            } else {
>               printf("FAIL: got SIGTRAP with event code %d\n", event_code);
>            }
>         } else {
>            printf("FAIL: unexpected stop signal %d\n", sig);
>         }
>      } else if (WIFEXITED(waitstat)) {
>         int es = WEXITSTATUS(waitstat);
>         printf("FAIL: unexpected exit status %d\n", es);
>      } else if (WIFSIGNALED(waitstat)) {
>         int sig = WTERMSIG(waitstat);
>         printf("FAIL: unexpected termination signal: %d\n", sig);
>      } else {
>         printf("FAIL: unknown waitstat: 0x%x for kid %d\n", waitstat, (int)kid);
>      }
>
>      /* Now let kid die (Oh no! The religious right will come after me!) */
>
>      if (ptrace(PTRACE_CONT, kid, 0, 0) == -1) {
>         fatal_error("exitcode parent", "ptrace(PTRACE_CONT)");
>      }
>      if (waitpid(kid, &waitstat, WUNTRACED|__WALL) != kid) {
>         fatal_error("exitcode parent", "waitpid(kid)");
>      }
>   }
>   return 0;
>}

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