#include <stdio.h>
#include <string.h>
#include <mntent.h>
#include <errno.h>

FILE* setmntent(const char* name, const char* mode) {
  return fopen(name, mode);
}

int endmntent(FILE* f) {
  if (f)
    fclose(f);
  return 1;
}

struct mntent* getmntent_r(FILE* f,
                           struct mntent* mnt,
                           char* linebuf,
                           int buflen) {
  int cnt, n[8];

  mnt->mnt_freq = 0;
  mnt->mnt_passno = 0;

  do {
    fgets(linebuf, buflen, f);
    if (feof(f) || ferror(f))
      return 0;
    if (!strchr(linebuf, '\n')) {
      fscanf(f, "%*[^\n]%*[\n]");
      errno = ERANGE;
      return 0;
    }
    cnt = sscanf(linebuf, " %n%*s%n %n%*s%n %n%*s%n %n%*s%n %d %d", n, n + 1,
                 n + 2, n + 3, n + 4, n + 5, n + 6, n + 7, &mnt->mnt_freq,
                 &mnt->mnt_passno);
  } while (cnt < 2 || linebuf[n[0]] == '#');

  linebuf[n[1]] = 0;
  linebuf[n[3]] = 0;
  linebuf[n[5]] = 0;
  linebuf[n[7]] = 0;

  mnt->mnt_fsname = linebuf + n[0];
  mnt->mnt_dir = linebuf + n[2];
  mnt->mnt_type = linebuf + n[4];
  mnt->mnt_opts = linebuf + n[6];

  return mnt;
}

struct mntent* getmntent(FILE* f) {
  static char linebuf[256];
  static struct mntent mnt;
  return getmntent_r(f, &mnt, linebuf, sizeof linebuf);
}

int addmntent(FILE* f, const struct mntent* mnt) {
  if (fseek(f, 0, SEEK_END))
    return 1;
  return fprintf(f, "%s\t%s\t%s\t%s\t%d\t%d\n", mnt->mnt_fsname, mnt->mnt_dir,
                 mnt->mnt_type, mnt->mnt_opts, mnt->mnt_freq,
                 mnt->mnt_passno) < 0;
}

char* hasmntopt(const struct mntent* mnt, const char* opt) {
  return strstr(mnt->mnt_opts, opt);
}