Attachment 317986 Details for Bug 464520 – test-vfork.c source file

test-vfork.c source file

test-vfork.c (text/plain), 4.84 KB, created by Tom Horsley on 2008-09-29 14:32:08 UTC

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Creator: Tom Horsley

Created: 2008-09-29 14:32:08 UTC

Size: 4.84 KB

patch

obsolete

>#include <stdio.h>
>#include <sys/ptrace.h>
>#include <sys/types.h>
>#include <signal.h>
>#include <unistd.h>
>#include <stdlib.h>
>#include <sys/wait.h>
>
>/*
>// On 2.6.26 kernels, vfork() no longer provides a parent stopped
>// notification when the process that vforks is run under ptrace with all
>// the PTRACE_O_* flags set to follow forks.
>*/
>
>char *
>signal_name(int signum) {
>   switch (signum) {
>#ifdef SIGHUP
>   case SIGHUP: return "SIGHUP";
>#endif
>#ifdef SIGINT
>   case SIGINT: return "SIGINT";
>#endif
>#ifdef SIGQUIT
>   case SIGQUIT: return "SIGQUIT";
>#endif
>#ifdef SIGILL
>   case SIGILL: return "SIGILL";
>#endif
>#ifdef SIGTRAP
>   case SIGTRAP: return "SIGTRAP";
>#endif
>#ifdef SIGABRT
>   case SIGABRT: return "SIGABRT";
>#endif
>#ifdef SIGBUS
>   case SIGBUS: return "SIGBUS";
>#endif
>#ifdef SIGFPE
>   case SIGFPE: return "SIGFPE";
>#endif
>#ifdef SIGKILL
>   case SIGKILL: return "SIGKILL";
>#endif
>#ifdef SIGUSR1
>   case SIGUSR1: return "SIGUSR1";
>#endif
>#ifdef SIGSEGV
>   case SIGSEGV: return "SIGSEGV";
>#endif
>#ifdef SIGUSR2
>   case SIGUSR2: return "SIGUSR2";
>#endif
>#ifdef SIGPIPE
>   case SIGPIPE: return "SIGPIPE";
>#endif
>#ifdef SIGALRM
>   case SIGALRM: return "SIGALRM";
>#endif
>#ifdef SIGTERM
>   case SIGTERM: return "SIGTERM";
>#endif
>#ifdef SIGSTKFLT
>   case SIGSTKFLT: return "SIGSTKFLT";
>#endif
>#ifdef SIGCHLD
>   case SIGCHLD: return "SIGCHLD";
>#endif
>#ifdef SIGCONT
>   case SIGCONT: return "SIGCONT";
>#endif
>#ifdef SIGSTOP
>   case SIGSTOP: return "SIGSTOP";
>#endif
>#ifdef SIGTSTP
>   case SIGTSTP: return "SIGTSTP";
>#endif
>#ifdef SIGTTIN
>   case SIGTTIN: return "SIGTTIN";
>#endif
>#ifdef SIGTTOU
>   case SIGTTOU: return "SIGTTOU";
>#endif
>#ifdef SIGURG
>   case SIGURG: return "SIGURG";
>#endif
>#ifdef SIGXCPU
>   case SIGXCPU: return "SIGXCPU";
>#endif
>#ifdef SIGXFSZ
>   case SIGXFSZ: return "SIGXFSZ";
>#endif
>#ifdef SIGVTALRM
>   case SIGVTALRM: return "SIGVTALRM";
>#endif
>#ifdef SIGPROF
>   case SIGPROF: return "SIGPROF";
>#endif
>#ifdef SIGWINCH
>   case SIGWINCH: return "SIGWINCH";
>#endif
>#ifdef SIGIO
>   case SIGIO: return "SIGIO";
>#endif
>#ifdef SIGLOST
>   case SIGLOST: return "SIGLOST";
>#endif
>#ifdef SIGPWR
>   case SIGPWR: return "SIGPWR";
>#endif
>#ifdef SIGSYS
>   case SIGSYS: return "SIGSYS";
>#endif
>   default:
>      {
>         static char sval[512];
>         sprintf(sval, "signal %d", signum);
>         return sval;
>      }
>   }
>}
>
>char *
>status_string(int kidstat) {
>   static char rval[512];
>   if (WIFEXITED(kidstat)) {
>      if (WEXITSTATUS(kidstat) == 0) {
>         sprintf(rval, "exited normally");
>      } else {
>         sprintf(rval, "exited with status %d", WEXITSTATUS(kidstat));
>      }
>   } else if (WIFSIGNALED(kidstat)) {
>      sprintf(rval, "terminated with %s", signal_name(WTERMSIG(kidstat)));
>   } else if (WIFSTOPPED(kidstat)) {
>      sprintf(rval, "stopped with %s", signal_name(WSTOPSIG(kidstat)));
>   } else {
>      sprintf(rval, "unrecognized status %#x", kidstat);
>   }
>   return rval;
>}
>
>static void
>test_vfork() {
>   pid_t gkid;
>   if (ptrace(PTRACE_TRACEME, 0, 0, 0) == -1) {
>      perror("ptrace(PTRACE_TRACEME)");
>      exit(2);
>   }
>
>   /* First, let parent know I'm here by sending myself a signal */
>
>   if (kill(getpid(), SIGUSR1) == -1) {
>      perror("kill");
>      exit(2);
>   }
>
>   /* Now vfork() and see what parent thinks of that... */
>
>   gkid = vfork();
>   if (gkid == (pid_t)-1) {
>      perror("vfork");
>   }
>   exit(0);
>}
>
>int
>main(int argc, char ** argv) {
>   pid_t child;
>
>   child = fork();
>   if (child == (pid_t)-1) {
>      perror("fork");
>      exit(2);
>   } else if (child == 0) {
>      test_vfork();
>   } else {
>      /* I am the parent, I'll be debugging the child which will
>       * call vfork(). The first thing I expect to see from the
>       * child is a SIGUSR1 it sends to itself.
>       */
>      int waitstat;
>      printf("Child process is %d\n", (int)child);
>      if (waitpid(child, &waitstat, WUNTRACED|__WALL) != child) {
>         perror("waitpid");
>         exit(2);
>      }
>      /* Set all the trace flags so we'll follow fork and wot-not */
>      if (ptrace(PTRACE_SETOPTIONS, child, 0,
>                    PTRACE_O_TRACEFORK|
>                     PTRACE_O_TRACEVFORK|
>                      PTRACE_O_TRACECLONE|
>                       PTRACE_O_TRACEEXEC|
>                        PTRACE_O_TRACEEXIT) == -1) {
>         perror("ptrace(PTRACE_SETOPTIONS)");
>         exit(2);
>      }
>      
>      /* Now I continue the child, but don't pass the SIGUSR1
>       * so it will just execute normally without getting the signal.
>       */
>      if (ptrace(PTRACE_CONT, child, 0, 0) == -1) {
>         perror("ptrace");
>         exit(2);
>      }
>      /* Now loop forever, printing info about any status I get. */
>      for ( ; ; ) {
>         pid_t kid = waitpid((pid_t)-1, &waitstat, WUNTRACED|__WALL);
>         if (kid == (pid_t)-1) {
>            perror("waitpid");
>            exit(2);
>         }
>         printf("Status for PID %d: %s\n", (int)kid, status_string(waitstat));
>      }
>   }
>}

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Attachments on bug 464520: 317986 | 319218 | 319237 | 321611