text: /*
   * libhugetlbfs - Easy use of Linux hugepages
   * Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public License
   * as published by the Free Software Foundation; either version 2.1 of
   * the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
   */
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <errno.h>
  #include <signal.h>
  #include <sys/mman.h>
  
  #include <hugetlbfs.h>
  
  #include "hugetests.h"
  
  /*
   * Test rationale:
   *
   * Some kernel have a bug in the positioning of the test against
   * i_size.  This bug means that attempting to instantiate a page
   * beyond the end of a hugepage file can result in an OOM and SIGKILL
   * instead of the correct SIGBUS.
   *
   * This bug was fixed by commit ebed4bfc8da8df5b6b0bc4a5064a949f04683509.
   */
  static void sigbus_handler(int signum, siginfo_t *si, void *uc)
  {
  	PASS();
  }
  
  int main(int argc, char *argv[])
  {
  	long hpage_size;
  	int fd, fdx;
  	unsigned long totpages;
  	void *p, *q;
  	int i;
  	int err;
  	struct sigaction sa = {
  		.sa_sigaction = sigbus_handler,
  		.sa_flags = SA_SIGINFO,
  	};
  
  	test_init(argc, argv);
  
  	totpages = read_meminfo("HugePages_Free:");
  
  	hpage_size = check_hugepagesize();
  
  	fd = hugetlbfs_unlinked_fd();
  	if (fd < 0)
  		FAIL("hugetlbfs_unlinked_fd()");
  
  	p = mmap(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
  	if (p == MAP_FAILED)
  		FAIL("mmap()");
  	err = ftruncate(fd, 0);
  	if (err)
  		FAIL("ftruncate(): %s", strerror(errno));
  
  	/* Now slurp up all the available pages */
  	fdx = hugetlbfs_unlinked_fd();
  	if (fdx < 0)
  		FAIL("hugetlbfs_unlinked_fd() 2");
  
  	q = mmap(NULL, totpages * hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
  		 fdx, 0);
  	if (q == MAP_FAILED)
  		FAIL("mmap() reserving all pages");
  
  	/* Touch the pages to ensure they're removed from the pool */
  	for (i = 0; i < totpages; i++) {
  		volatile char *x = (volatile char *)q + i*hpage_size;
  		*x = 0;
  	}
  
  	/* SIGBUS is what *should* happen */
  	err = sigaction(SIGBUS, &sa, NULL);
  	if (err)
  		FAIL("sigaction()");
  
  	*((volatile unsigned int *)p);
  
  	/* Should have SIGBUSed above, or (failed the test) with SIGKILL */
  	FAIL("Didn't SIGBUS or OOM");
  }
  