mount/mntent.c

   1 /* Private version of the libc *mntent() routines. */
   2 /* Note slightly different prototypes. */
   3
   4 /* 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
   5  * - added Native Language Support
   6  */
   7
   8 #include <stdio.h>
   9 #include <string.h>             /* for index */
  10 #include <ctype.h>              /* for isdigit */
  11 #include "mntent.h"
  12 #include "sundries.h"           /* for xmalloc */
  13 #include "nls.h"
  14
  15 /* Unfortunately the classical Unix /etc/mtab and /etc/fstab
  16    do not handle directory names containing spaces.
  17    Here we mangle them, replacing a space by \040.
  18    What do other Unices do? */
  19
  20 static unsigned char need_escaping[] = { ' ', '\t', '\n', '\\' };
  21
  22 static char *
  23 mangle(unsigned char *s) {
  24         char *ss, *sp;
  25         int n;
  26
  27         n = strlen(s);
  28         ss = sp = xmalloc(4*n+1);
  29         while(1) {
  30                 for (n = 0; n < sizeof(need_escaping); n++) {
  31                         if (*s == need_escaping[n]) {
  32                                 *sp++ = '\\';
  33                                 *sp++ = '0' + ((*s & 0300) >> 6);
  34                                 *sp++ = '0' + ((*s & 070) >> 3);
  35                                 *sp++ = '0' + (*s & 07);
  36                                 goto next;
  37                         }
  38                 }
  39                 *sp++ = *s;
  40                 if (*s == 0)
  41                         break;
  42         next:
  43                 s++;
  44         }
  45         return ss;
  46 }
  47
  48 static int
  49 is_space_or_tab (char c) {
  50         return (c == ' ' || c == '\t');
  51 }
  52
  53 static char *
  54 skip_spaces(char *s) {
  55         while (is_space_or_tab(*s))
  56                 s++;
  57         return s;
  58 }
  59
  60 static char *
  61 skip_nonspaces(char *s) {
  62         while (*s && !is_space_or_tab(*s))
  63                 s++;
  64         return s;
  65 }
  66
  67 #define isoctal(a) (((a) & ~7) == '0')
  68
  69 /* returns malloced pointer - no more strdup required */
  70 static char *
  71 unmangle(char *s) {
  72         char *ret, *ss, *sp;
  73
  74         ss = skip_nonspaces(s);
  75         ret = sp = xmalloc(ss-s+1);
  76         while(s != ss) {
  77                 if (*s == '\\' && isoctal(s[1]) && isoctal(s[2]) && isoctal(s[3])) {
  78                         *sp++ = 64*(s[1] & 7) + 8*(s[2] & 7) + (s[3] & 7);
  79                         s += 4;
  80                 } else
  81                         *sp++ = *s++;
  82         }
  83         *sp = 0;
  84         return ret;
  85 }
  86
  87 /*
  88  * fstat'ing the file and allocating a buffer holding all of it
  89  * may be a bad idea: if the file is /proc/mounts, the stat
  90  * returns 0.
  91  * (On the other hand, mangling and unmangling is meaningless
  92  *  for /proc/mounts.)
  93  */
  94
  95 mntFILE *
  96 my_setmntent (const char *file, char *mode) {
  97         mntFILE *mfp = xmalloc(sizeof(*mfp));
  98
  99         mfp->mntent_fp = fopen (file, mode);
 100         mfp->mntent_file = xstrdup(file);
 101         mfp->mntent_errs = (mfp->mntent_fp == NULL);
 102         mfp->mntent_softerrs = 0;
 103         mfp->mntent_lineno = 0;
 104         return mfp;
 105 }
 106
 107 void
 108 my_endmntent (mntFILE *mfp) {
 109         if (mfp) {
 110                 if (mfp->mntent_fp)
 111                         fclose(mfp->mntent_fp);
 112                 if (mfp->mntent_file)
 113                         free(mfp->mntent_file);
 114                 free(mfp);
 115         }
 116 }
 117
 118
 119 int
 120 my_addmntent (mntFILE *mfp, struct mntent *mnt) {
 121         char *m1, *m2, *m3, *m4;
 122         int res;
 123
 124         if (fseek (mfp->mntent_fp, 0, SEEK_END))
 125                 return 1;                       /* failure */
 126
 127         m1 = mangle(mnt->mnt_fsname);
 128         m2 = mangle(mnt->mnt_dir);
 129         m3 = mangle(mnt->mnt_type);
 130         m4 = mangle(mnt->mnt_opts);
 131
 132         res = ((fprintf (mfp->mntent_fp, "%s %s %s %s %d %d\n",
 133                          m1, m2, m3, m4, mnt->mnt_freq, mnt->mnt_passno)
 134                 < 0) ? 1 : 0);
 135
 136         free(m1);
 137         free(m2);
 138         free(m3);
 139         free(m4);
 140         return res;
 141 }
 142
 143 /* Read the next entry from the file fp. Stop reading at an incorrect entry. */
 144 struct mntent *
 145 my_getmntent (mntFILE *mfp) {
 146         static char buf[4096];
 147         static struct mntent me;
 148         char *s;
 149
 150  again:
 151         if (mfp->mntent_errs || mfp->mntent_softerrs >= ERR_MAX)
 152                 return NULL;
 153
 154         /* read the next non-blank non-comment line */
 155         do {
 156                 if (fgets (buf, sizeof(buf), mfp->mntent_fp) == NULL)
 157                         return NULL;
 158
 159                 mfp->mntent_lineno++;
 160                 s = index (buf, '\n');
 161                 if (s == NULL) {
 162                         /* Missing final newline?  Otherwise extremely */
 163                         /* long line - assume file was corrupted */
 164                         if (feof(mfp->mntent_fp)) {
 165                                 fprintf(stderr, _("[mntent]: warning: no final "
 166                                         "newline at the end of %s\n"),
 167                                         mfp->mntent_file);
 168                                 s = index (buf, 0);
 169                         } else {
 170                                 mfp->mntent_errs = 1;
 171                                 goto err;
 172                         }
 173                 }
 174                 *s = 0;
 175                 if (--s >= buf && *s == '\r')
 176                         *s = 0;
 177                 s = skip_spaces(buf);
 178         } while (*s == '\0' || *s == '#');
 179
 180         me.mnt_fsname = unmangle(s);
 181         s = skip_nonspaces(s);
 182         s = skip_spaces(s);
 183         me.mnt_dir = unmangle(s);
 184         s = skip_nonspaces(s);
 185         s = skip_spaces(s);
 186         me.mnt_type = unmangle(s);
 187         s = skip_nonspaces(s);
 188         s = skip_spaces(s);
 189         me.mnt_opts = unmangle(s);
 190         s = skip_nonspaces(s);
 191         s = skip_spaces(s);
 192
 193         if(isdigit(*s)) {
 194                 me.mnt_freq = atoi(s);
 195                 while(isdigit(*s)) s++;
 196         } else
 197                 me.mnt_freq = 0;
 198         if(*s && !is_space_or_tab(*s))
 199                 goto err;
 200
 201         s = skip_spaces(s);
 202         if(isdigit(*s)) {
 203                 me.mnt_passno = atoi(s);
 204                 while(isdigit(*s)) s++;
 205         } else
 206                 me.mnt_passno = 0;
 207         if(*s && !is_space_or_tab(*s))
 208                 goto err;
 209
 210         /* allow more stuff, e.g. comments, on this line */
 211
 212         return &me;
 213
 214  err:
 215         mfp->mntent_softerrs++;
 216         fprintf(stderr, _("[mntent]: line %d in %s is bad%s\n"),
 217                 mfp->mntent_lineno, mfp->mntent_file,
 218                 (mfp->mntent_errs || mfp->mntent_softerrs >= ERR_MAX) ?
 219                 _("; rest of file ignored") : "");
 220         goto again;
 221 }