libbb/parse_mode.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) many different people.  If you wrote this, please
   6  * acknowledge your work.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21  * USA
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include "libbb.h"
  27
  28
  29 /* This function parses the sort of string you might pass
  30  * to chmod (i.e., [ugoa]{+|-|=}[rwxst] ) and returns the
  31  * correct mode described by the string. */
  32 extern int parse_mode(const char *s, mode_t * theMode)
  33 {
  34         static const mode_t group_set[] = {
  35                 S_ISUID | S_IRWXU,              /* u */
  36                 S_ISGID | S_IRWXG,              /* g */
  37                 S_IRWXO,                                /* o */
  38                 S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO /* a */
  39         };
  40
  41         static const mode_t mode_set[] = {
  42                 S_IRUSR | S_IRGRP | S_IROTH, /* r */
  43                 S_IWUSR | S_IWGRP | S_IWOTH, /* w */
  44                 S_IXUSR | S_IXGRP | S_IXOTH, /* x */
  45                 S_ISUID | S_ISGID,              /* s */
  46                 S_ISVTX                                 /* t */
  47         };
  48
  49         static const char group_chars[] = "ugoa";
  50         static const char mode_chars[] = "rwxst";
  51
  52         const char *p;
  53
  54         mode_t andMode =
  55                 S_ISVTX | S_ISUID | S_ISGID | S_IRWXU | S_IRWXG | S_IRWXO;
  56         mode_t orMode = 0;
  57         mode_t mode;
  58         mode_t groups;
  59         char type;
  60         char c;
  61
  62         if (s==NULL) {
  63                 return (FALSE);
  64         }
  65
  66         do {
  67                 mode = 0;
  68                 groups = 0;
  69         NEXT_GROUP:
  70                 if ((c = *s++) == '\0') {
  71                         return -1;
  72                 }
  73                 for (p=group_chars ; *p ; p++) {
  74                         if (*p == c) {
  75                                 groups |= group_set[(int)(p-group_chars)];
  76                                 goto NEXT_GROUP;
  77                         }
  78                 }
  79                 switch (c) {
  80                         case '=':
  81                         case '+':
  82                         case '-':
  83                                 type = c;
  84                                 if (groups == 0) { /* The default is "all" */
  85                                         groups |= S_ISUID | S_ISGID | S_ISVTX
  86                                                         | S_IRWXU | S_IRWXG | S_IRWXO;
  87                                 }
  88                                 break;
  89                         default:
  90                                 if ((c < '0') || (c > '7') || (mode | groups)) {
  91                                         return (FALSE);
  92                                 } else {
  93                                         *theMode = strtol(--s, NULL, 8);
  94                                         return (TRUE);
  95                                 }
  96                 }
  97
  98         NEXT_MODE:
  99                 if (((c = *s++) != '\0') && (c != ',')) {
 100                         for (p=mode_chars ; *p ; p++) {
 101                                 if (*p == c) {
 102                                         mode |= mode_set[(int)(p-mode_chars)];
 103                                         goto NEXT_MODE;
 104                                 }
 105                         }
 106                         break;                          /* We're done so break out of loop.*/
 107                 }
 108                 switch (type) {
 109                         case '=':
 110                                 andMode &= ~(groups); /* Now fall through. */
 111                         case '+':
 112                                 orMode |= mode & groups;
 113                                 break;
 114                         case '-':
 115                                 andMode &= ~(mode & groups);
 116                                 orMode &= ~(mode & groups);
 117                                 break;
 118                 }
 119         } while (c == ',');
 120
 121         *theMode &= andMode;
 122         *theMode |= orMode;
 123
 124         return TRUE;
 125 }
 126
 127 /* END CODE */
 128 /*
 129 Local Variables:
 130 c-file-style: "linux"
 131 c-basic-offset: 4
 132 tab-width: 4
 133 End:
 134 */