os161-assignments/userland/testbin/rmdirtest/rmdirtest.c

/*
 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
 *	The President and Fellows of Harvard College.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * rmdirtest.c
 *
 *      Tests file system synchronization and directory implementation by
 *      removing the current directory under itself and then trying to do
 *      things. It's ok for most of those things to fail, but the system
 *      shouldn't crash.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <limits.h>
#include <err.h>

static const char testdir[] = "testdir";
static char startpoint[PATH_MAX - sizeof(testdir)];

/*
 * Create the test directory, and change into it, remembering
 * where we came from.
 */

static void startup(void) {
  if (getcwd(startpoint, sizeof(startpoint)) == NULL) {
    err(1, "getcwd (not in test dir)");
  }

  if (mkdir(testdir, 0775) < 0) {
    err(1, "%s: mkdir", testdir);
  }

  if (chdir(testdir) < 0) {
    err(1, "%s: chdir", testdir);
  }
}

/*
 * Remove the test directory.
 *
 * Note that even though it's the current directory, we can't do it
 * with rmdir(".") - what that would try to do is remove the "." entry
 * from the current directory, which is justifiably prohibited.
 */

static void killdir(void) {
  char tmp[PATH_MAX];

  snprintf(tmp, sizeof(tmp), "%s/%s", startpoint, testdir);
  if (rmdir(tmp) < 0) {
    err(1, "%s: rmdir", tmp);
  }
}

/*
 * Leave the test directory and go back to where we came from, so we
 * can try again.
 */

static void finish(void) {
  if (chdir(startpoint) < 0) {
    err(1, "%s: chdir", startpoint);
  }
}

/*************************************************************/

/*
 * Basic test - just try removing the directory without doing anything
 * evil.
 */
static void test1(void) {
  printf("Making %s\n", testdir);
  startup();

  printf("Removing %s while in it\n", testdir);
  killdir();

  printf("Leaving the test directory\n");
  finish();
}

/*
 * Now do it while we also have the directory open.
 */

static void test2(void) {
  int fd;

  printf("Now trying with the directory open...\n");
  startup();
  fd = open(".", O_RDONLY);
  if (fd < 0) {
    err(1, ".: open");
  }
  killdir();
  finish();

  /* close *after* leaving, just for excitement */
  if (close(fd) < 0) {
    err(1, "removed %s: close", testdir);
  }
}

/*
 * Now see if . and .. work after rmdir.
 */

static void test3(void) {
  char buf[PATH_MAX];
  int fd;

  printf("Checking if . exists after rmdir\n");
  startup();
  killdir();

  fd = open(".", O_RDONLY);
  if (fd < 0) {
    switch (errno) {
    case EINVAL:
    case EIO:
    case ENOENT:
      break;
    default:
      err(1, ".");
      break;
    }
  } else {
    close(fd);
  }

  fd = open("..", O_RDONLY);
  if (fd < 0) {
    switch (errno) {
    case EINVAL:
    case EIO:
    case ENOENT:
      break;
    default:
      err(1, "..");
      break;
    }
  } else {
    warnx("..: openable after rmdir - might be bad");
    close(fd);
  }

  snprintf(buf, sizeof(buf), "../%s", testdir);
  fd = open(buf, O_RDONLY);
  if (fd < 0) {
    switch (errno) {
    case EINVAL:
    case EIO:
    case ENOENT:
      break;
    default:
      err(1, "%s", buf);
      break;
    }
  } else {
    errx(1, "%s: works after rmdir", buf);
  }

  finish();
}

/*
 * Now try to create files.
 */

static void test4(void) {
  char buf[4096];
  int fd;

  printf("Checking if creating files works after rmdir...\n");
  startup();
  killdir();

  fd = open("newfile", O_WRONLY | O_CREAT | O_TRUNC, 0664);
  if (fd < 0) {
    switch (errno) {
    case EINVAL:
    case EIO:
    case ENOENT:
      break;
    default:
      err(1, "%s", buf);
      break;
    }
  } else {
    warnx("newfile: creating files after rmdir works");
    warnx("(this is only ok if the space gets reclaimed)");

    /*
     * Waste a bunch of space so we'll be able to tell
     */
    memset(buf, 'J', sizeof(buf));
    write(fd, buf, sizeof(buf));
    write(fd, buf, sizeof(buf));
    write(fd, buf, sizeof(buf));
    write(fd, buf, sizeof(buf));
    close(fd);
  }

  finish();
}

/*
 * Now try to create directories.
 */

static void test5(void) {
  printf("Checking if creating subdirs works after rmdir...\n");
  startup();
  killdir();

  if (mkdir("newdir", 0775) < 0) {
    switch (errno) {
    case EINVAL:
    case EIO:
    case ENOENT:
      break;
    default:
      err(1, "mkdir in removed dir");
      break;
    }
  } else {
    warnx("newfile: creating directories after rmdir works");
    warnx("(this is only ok if the space gets reclaimed)");

    /*
     * Waste a bunch of space so we'll be able to tell
     */
    mkdir("newdir/t0", 0775);
    mkdir("newdir/t1", 0775);
    mkdir("newdir/t2", 0775);
    mkdir("newdir/t3", 0775);
    mkdir("newdir/t4", 0775);
    mkdir("newdir/t5", 0775);
  }

  finish();
}

/*
 * Now try listing the directory.
 */
static void test6(void) {
  char buf[PATH_MAX];
  int fd, len;

  printf("Now trying to list the directory...\n");
  startup();
  fd = open(".", O_RDONLY);
  if (fd < 0) {
    err(1, ".: open");
  }
  killdir();

  while ((len = getdirentry(fd, buf, sizeof(buf) - 1)) > 0) {
    if ((unsigned)len >= sizeof(buf) - 1) {
      errx(1, ".: getdirentry: returned invalid length");
    }
    buf[len] = 0;
    if (!strcmp(buf, ".") || !strcmp(buf, "..")) {
      /* these are allowed to appear */
      continue;
    }
    errx(1, ".: getdirentry: returned unexpected name %s", buf);
  }
  if (len == 0) {
    /* EOF - ok */
  } else { /* len < 0 */
    switch (errno) {
    case EINVAL:
    case EIO:
      break;
    default:
      err(1, ".: getdirentry");
      break;
    }
  }

  finish();

  /* close *after* leaving, just for excitement */
  if (close(fd) < 0) {
    err(1, "removed %s: close", testdir);
  }
}

/*
 * Try getcwd.
 */
static void test7(void) {
  char buf[PATH_MAX];

  startup();
  killdir();
  if (getcwd(buf, sizeof(buf)) == NULL) {
    switch (errno) {
    case EINVAL:
    case EIO:
    case ENOENT:
      break;
    default:
      err(1, "getcwd after removing %s", testdir);
      break;
    }
  } else {
    errx(1, "getcwd after removing %s: succeeded (got %s)", testdir, buf);
  }

  finish();
}

/**************************************************************/

int main(void) {
  test1();
  test2();
  test3();
  test4();
  test5();
  test6();
  test7();

  printf("Whew... survived.\n");
  return 0;
}