Attachment 309666 Details for Bug 451849 – test case: 2 1-file C programs

test case: 2 1-file C programs

ptrace_bug.txt (text/plain), 4.07 KB, created by Tom Fleck on 2008-06-17 19:29:57 UTC

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Creator: Tom Fleck

Created: 2008-06-17 19:29:57 UTC

Size: 4.07 KB

patch

obsolete

>
>/** app.c ----------------------------------------------------------- */
>#include <unistd.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <errno.h>
>#include <signal.h>
>
>/* app waits on sigusr1 before exec'ing to ensure that even the quickest
> * app gets traced */
>sigset_t oldset, sigset;
>static void block_sigusr1(void)
>{
>   sigemptyset (&sigset);
>   sigaddset (&sigset, SIGUSR1);
>   sigprocmask (SIG_BLOCK, &sigset, &oldset);
>}
>static void unblock_sigusr1(void)
>{
>   sigprocmask (SIG_SETMASK, &oldset, 0);
>}
>static void waitfor_sigusr1(void)
>{
>   int sig;
>   sigwait (&sigset, &sig);
>}
>
>int main (int argc, char **argv)
>{
>   int app = getpid();
>
>/* block sigusr1 before fork so debugger doesn't kill app */
>   block_sigusr1();
>
>   printf("%d is waiting for signal %d...\n", app, SIGUSR1);
>   fflush(stdout);
>   waitfor_sigusr1();
>
>   printf("got it, continuing...\n"); fflush(stdout);
>   unblock_sigusr1();
>
>   execl ("/bin/pwd", "pwd", NULL);
>
>   perror("returned from exec");
>   return -1;
>}
>
>/** deb.c ----------------------------------------------------------------- */
>#include <unistd.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <errno.h>
>#include <sys/wait.h>
>#include <sys/ptrace.h>
>#include <signal.h>
>
>#define USAGE "Usage: %s [-w] app_pid\n" \
>" -w => apply workaround to avoid bug\n"
>
>static int do_workaround = 0;
>static void getargs(int argc, char **argv, int *app_pid);
>
>/* after fork, either parent or child can play debugger or application,
> * just pass in their pids */
>static void do_deb(int deb, int app);
>
>int main (int argc, char **argv)
>{
>   int app;
>   int deb = getpid();
>   int Status;
>
>/* get pid, set do_workaround? */
>   getargs(argc, argv, &app);
>
>   printf("In deb=%d, attach\n", deb); fflush(stdout);
>   if (ptrace(PTRACE_ATTACH, app, 0, 0) == -1)
>   {
>      perror("attach failed"); fflush(stderr);
>      exit(1);
>   }
>   printf("In deb=%d, 1st wait(%d, ...)\n", deb, app); fflush(stdout);
>   Status = 0;
>   if (waitpid(app, &Status, 0) != -1)
>   {
>      printf("- 1st waitpid returned with %#x\n", Status);
>      fflush(stdout);
>   }
>   else
>   {
>      perror("* 1st waitpid failed"); fflush(stderr);
>   }
>
>   if (!do_workaround)
>   {
>      printf("In deb=%d, ptrace(PTRACE_CONT, %d, 0, %d)\n", deb, app,
>             SIGUSR1);
>      fflush(stdout);
>      if (ptrace (PTRACE_CONT, app, 0, SIGUSR1) == -1)
>      {
>         perror("PTRACE_CONT(SIGUSR1) failed"); fflush(stderr);
>         exit(2);
>      }
>   }
>   else
>   { /* do separate PTRACE_CONT(..., 0), kill(..., SIGUSR1) */
>      printf("In deb=%d, ptrace(PTRACE_CONT, %d, 0, 0)\n", deb, app);
>      fflush(stdout);
>      if (ptrace (PTRACE_CONT, app, 0, 0) == -1)
>      {
>         perror("PTRACE_CONT(0) failed"); fflush(stderr);
>         exit(2);
>      }
>      printf("In deb=%d, kill(%d, %d)\n", deb, app, SIGUSR1); fflush(stdout);
>      kill(app, SIGUSR1);
>   }
>
>/* wait for SIGTRAP from app's exec */
>   printf("In deb=%d, 2nd wait(%d, ...)\n", deb, app); fflush(stdout);
>   if (waitpid(app, &Status, 0) != -1)
>   {
>      printf("- 3rd waitpid returned with %#x\n", Status); fflush(stdout);
>      if (!(WIFSTOPPED(Status) && WSTOPSIG (Status) == SIGTRAP))
>      {
>         fprintf(stderr, "Didn't get SIGTRAP\n"); fflush(stderr);
>         exit(6);
>      }
>   }
>   else
>   {
>      perror("* 3rd waitpid failed"); fflush(stderr);
>      exit(7);
>   }
>
>   printf("In deb=%d, detach\n", deb); fflush(stdout);
>   if (ptrace(PTRACE_DETACH, app, 0, 0) == -1)
>   {
>      perror("detach failed"); fflush(stderr); exit(3);
>   }
>   printf("=== PASSED!\n");
>   return 0;
>}
>
>static void getargs(int argc, char **argv, int *app_pid)
>{
>   int i;
>   int pid = 0;
>   if (argc < 2)
>   {
>      fprintf(stderr, USAGE, argv[0]);
>      exit(0);
>   }
>   for (i = 1; i < argc; i++)
>   {
>      if (!strcmp(argv[i], "-w"))
>      {
>         do_workaround = 1;
>      }
>      else if ((*app_pid = atoi(argv[i])) == 0)
>      {
>         fprintf(stderr, "Invalid arg %s\n" USAGE, argv[i], argv[0]);
>         exit(1);
>      }
>   }
>}

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