/* Copyright (C) 2008  Emmanuel Varoquaux

   This file is part of XOS.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>. */

#include <getopt.h>
#include <error.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mount.h>
#include <errno.h>

static const char *mounts_path = "/proc/mounts";

static void print_mounts()
{
  int fd;
  char buf[4096];
  ssize_t n;

  if ((fd = open(mounts_path, O_RDONLY)) == -1)
    error(EXIT_FAILURE, errno, mounts_path);
  while (1) {
    if ((n = read(fd, buf, sizeof buf)) == -1)
      error(EXIT_FAILURE, errno, mounts_path);
    if (n == 0)
      break;
    if ((write(STDOUT_FILENO, buf, n)) == -1)
      error(EXIT_FAILURE, errno, "write error");
  }
  close(fd);
}

static void __attribute__ ((noreturn)) die_bad_usage()
{
  fprintf(stderr, "Try `%s --help' for more information.\n", program_invocation_name);
  exit(EXIT_FAILURE);
}

static void print_help()
{
  printf("Usage: %s [OPTION]\n", program_invocation_name);
  printf("   or: %s [OPTION] -t TYPE DEVICE DIR\n", program_invocation_name);
  puts("Mount a filesystem. If no argument is provided, list all mounted filesystems.");
  putchar('\n');
  puts("  -t, --types=TYPE  filesystem type");
  puts("  -h, --help        display this help and exit");
}

int main(int argc, char **argv)
{
  static const struct option longopts[] = {
    {"types", required_argument, NULL, 't'},
    {"help", no_argument, NULL, 'h'},
    {NULL, 0, NULL, 0}
  };

  const char *filesystemtype, *source, *target;
  int c;

  filesystemtype = NULL;
  while ((c = getopt_long(argc, argv, "t:h", longopts, NULL)) != -1)
    switch (c) {
    case 't':
      filesystemtype = optarg;
      break;
    case 'h':
      print_help();
      return EXIT_SUCCESS;
    case '?':
      die_bad_usage();
    }

  if (filesystemtype) {
    if (optind + 1 >= argc) {
      error(0, 0, "missing operand");
      die_bad_usage();
    }
    source = *argv[optind] ? argv[optind] : NULL;
    target = argv[optind + 1];
    if (mount(source, target, filesystemtype, 0, NULL) == -1)
      error(EXIT_FAILURE, errno, "failed to mount %s", source ? : filesystemtype);
  }
  else
    print_mounts();
  return EXIT_SUCCESS;
}