pipe6.c

gdb-6.8 Linux下的调试程序 最新版本

/* Check that writing an inordinate amount of data works (somewhat).
#notarget: cris*-*-elf
#output: got: a\nexit: 0\n
   This test-case will *not* work on host (or for real): the first
   pipemax+1 bytes will be successfully written.  It's just for
   exercising a rare execution path.  */

#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <unistd.h>
#include <sched.h>
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>

int pip[2];

int pipemax;

int
process (void *arg)
{
  char *s = arg;
  char *buf = calloc (pipemax * 100, 1);
  int ret;

  if (buf == NULL)
    abort ();

  *buf = *s;

  ret = write (pip[1], buf, pipemax * 100);
  if (ret != -1 || errno != EFBIG)
    {
      perror ("write");
      abort ();
    }

  return 0;
}

int
main (void)
{
  int retcode;
  int pid;
  int st = 0;
  long stack[16384];
  char buf[1];

  retcode = pipe (pip);

  if (retcode != 0)
    {
      fprintf (stderr, "Bad pipe %d\n", retcode);
      abort ();
    }

#ifdef PIPE_MAX
  pipemax = PIPE_MAX;
#else
  pipemax = fpathconf (pip[1], _PC_PIPE_BUF);
#endif

  if (pipemax <= 0)
    {
      fprintf (stderr, "Bad pipemax %d\n", pipemax);
      abort ();
    }

  pid = clone (process, (char *) stack + sizeof (stack) - 64,
	       (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND)
	       | SIGCHLD, "ab");
  if (pid <= 0)
    {
      fprintf (stderr, "Bad clone %d\n", pid);
      abort ();
    }

  while ((retcode = read (pip[0], buf, 1)) == 0)
    ;

  if (retcode != 1)
    {
      fprintf (stderr, "Bad read 1: %d\n", retcode);
      abort ();
    }

  printf ("got: %c\n", buf[0]);

  if (close (pip[0]) != 0)
    {
      perror ("pip close");
      abort ();
    }

  retcode = waitpid (pid, &st, __WALL);

  if (retcode != pid || !WIFEXITED (st))
    {
      fprintf (stderr, "Bad wait %d:%d %x\n", pid, retcode, st);
      perror ("errno");
      abort ();
    }

  printf ("exit: %d\n", WEXITSTATUS (st));
  return 0;
}