src/misc/mntent.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <mntent.h>
   4 #include <errno.h>
   5 #include <limits.h>
   6
   7 static char *internal_buf;
   8 static size_t internal_bufsize;
   9
  10 #define SENTINEL (char *)&internal_buf
  11
  12 FILE *setmntent(const char *name, const char *mode)
  13 {
  14         return fopen(name, mode);
  15 }
  16
  17 int endmntent(FILE *f)
  18 {
  19         if (f) fclose(f);
  20         return 1;
  21 }
  22
  23 struct mntent *getmntent_r(FILE *f, struct mntent *mnt, char *linebuf, int buflen)
  24 {
  25         int n[8], use_internal = (linebuf == SENTINEL);
  26         size_t len, i;
  27
  28         mnt->mnt_freq = 0;
  29         mnt->mnt_passno = 0;
  30
  31         do {
  32                 if (use_internal) {
  33                         getline(&internal_buf, &internal_bufsize, f);
  34                         linebuf = internal_buf;
  35                 } else {
  36                         fgets(linebuf, buflen, f);
  37                 }
  38                 if (feof(f) || ferror(f)) return 0;
  39                 if (!strchr(linebuf, '\n')) {
  40                         fscanf(f, "%*[^\n]%*[\n]");
  41                         errno = ERANGE;
  42                         return 0;
  43                 }
  44
  45                 len = strlen(linebuf);
  46                 if (len > INT_MAX) continue;
  47                 for (i = 0; i < sizeof n / sizeof *n; i++) n[i] = len;
  48                 sscanf(linebuf, " %n%*s%n %n%*s%n %n%*s%n %n%*s%n %d %d",
  49                         n, n+1, n+2, n+3, n+4, n+5, n+6, n+7,
  50                         &mnt->mnt_freq, &mnt->mnt_passno);
  51         } while (linebuf[n[0]] == '#' || n[1]==len);
  52
  53         linebuf[n[1]] = 0;
  54         linebuf[n[3]] = 0;
  55         linebuf[n[5]] = 0;
  56         linebuf[n[7]] = 0;
  57
  58         mnt->mnt_fsname = linebuf+n[0];
  59         mnt->mnt_dir = linebuf+n[2];
  60         mnt->mnt_type = linebuf+n[4];
  61         mnt->mnt_opts = linebuf+n[6];
  62
  63         return mnt;
  64 }
  65
  66 struct mntent *getmntent(FILE *f)
  67 {
  68         static struct mntent mnt;
  69         return getmntent_r(f, &mnt, SENTINEL, 0);
  70 }
  71
  72 int addmntent(FILE *f, const struct mntent *mnt)
  73 {
  74         if (fseek(f, 0, SEEK_END)) return 1;
  75         return fprintf(f, "%s\t%s\t%s\t%s\t%d\t%d\n",
  76                 mnt->mnt_fsname, mnt->mnt_dir, mnt->mnt_type, mnt->mnt_opts,
  77                 mnt->mnt_freq, mnt->mnt_passno) < 0;
  78 }
  79
  80 char *hasmntopt(const struct mntent *mnt, const char *opt)
  81 {
  82         return strstr(mnt->mnt_opts, opt);
  83 }