chmod.c

   1 /*
   2  * Implement the core of the --chmod option.
   3  *
   4  * Copyright (C) 2002 Scott Howard
   5  * Copyright (C) 2005-2007 Wayne Davison
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, visit the http://fsf.org website.
  19  */
  20
  21 #include "rsync.h"
  22
  23 extern mode_t orig_umask;
  24
  25 #define FLAG_X_KEEP (1<<0)
  26 #define FLAG_DIRS_ONLY (1<<1)
  27 #define FLAG_FILES_ONLY (1<<2)
  28
  29 struct chmod_mode_struct {
  30         struct chmod_mode_struct *next;
  31         int ModeAND, ModeOR;
  32         char flags;
  33 };
  34
  35 #define CHMOD_ADD 1
  36 #define CHMOD_SUB 2
  37 #define CHMOD_EQ  3
  38
  39 #define STATE_ERROR 0
  40 #define STATE_1ST_HALF 1
  41 #define STATE_2ND_HALF 2
  42
  43 /* Parse a chmod-style argument, and break it down into one or more AND/OR
  44  * pairs in a linked list.  We return a pointer to new items on succcess
  45  * (appending the items to the specified list), or NULL on error. */
  46 struct chmod_mode_struct *parse_chmod(const char *modestr,
  47                                       struct chmod_mode_struct **root_mode_ptr)
  48 {
  49         int state = STATE_1ST_HALF;
  50         int where = 0, what = 0, op = 0, topbits = 0, topoct = 0, flags = 0;
  51         struct chmod_mode_struct *first_mode = NULL, *curr_mode = NULL,
  52                                  *prev_mode = NULL;
  53
  54         while (state != STATE_ERROR) {
  55                 if (!*modestr || *modestr == ',') {
  56                         int bits;
  57
  58                         if (!op) {
  59                                 state = STATE_ERROR;
  60                                 break;
  61                         }
  62                         prev_mode = curr_mode;
  63                         curr_mode = new_array(struct chmod_mode_struct, 1);
  64                         if (prev_mode)
  65                                 prev_mode->next = curr_mode;
  66                         else
  67                                 first_mode = curr_mode;
  68                         curr_mode->next = NULL;
  69
  70                         if (where)
  71                                 bits = where * what;
  72                         else {
  73                                 where = 0111;
  74                                 bits = (where * what) & ~orig_umask;
  75                         }
  76
  77                         switch (op) {
  78                         case CHMOD_ADD:
  79                                 curr_mode->ModeAND = CHMOD_BITS;
  80                                 curr_mode->ModeOR  = bits + topoct;
  81                                 break;
  82                         case CHMOD_SUB:
  83                                 curr_mode->ModeAND = CHMOD_BITS - bits - topoct;
  84                                 curr_mode->ModeOR  = 0;
  85                                 break;
  86                         case CHMOD_EQ:
  87                                 curr_mode->ModeAND = CHMOD_BITS - (where * 7) - (topoct ? topbits : 0);
  88                                 curr_mode->ModeOR  = bits + topoct;
  89                                 break;
  90                         }
  91
  92                         curr_mode->flags = flags;
  93
  94                         if (!*modestr)
  95                                 break;
  96                         modestr++;
  97
  98                         state = STATE_1ST_HALF;
  99                         where = what = op = topoct = topbits = flags = 0;
 100                 }
 101
 102                 if (state != STATE_2ND_HALF) {
 103                         switch (*modestr) {
 104                         case 'D':
 105                                 if (flags & FLAG_FILES_ONLY)
 106                                         state = STATE_ERROR;
 107                                 flags |= FLAG_DIRS_ONLY;
 108                                 break;
 109                         case 'F':
 110                                 if (flags & FLAG_DIRS_ONLY)
 111                                         state = STATE_ERROR;
 112                                 flags |= FLAG_FILES_ONLY;
 113                                 break;
 114                         case 'u':
 115                                 where |= 0100;
 116                                 topbits |= 04000;
 117                                 break;
 118                         case 'g':
 119                                 where |= 0010;
 120                                 topbits |= 02000;
 121                                 break;
 122                         case 'o':
 123                                 where |= 0001;
 124                                 break;
 125                         case 'a':
 126                                 where |= 0111;
 127                                 break;
 128                         case '+':
 129                                 op = CHMOD_ADD;
 130                                 state = STATE_2ND_HALF;
 131                                 break;
 132                         case '-':
 133                                 op = CHMOD_SUB;
 134                                 state = STATE_2ND_HALF;
 135                                 break;
 136                         case '=':
 137                                 op = CHMOD_EQ;
 138                                 state = STATE_2ND_HALF;
 139                                 break;
 140                         default:
 141                                 state = STATE_ERROR;
 142                                 break;
 143                         }
 144                 } else {
 145                         switch (*modestr) {
 146                         case 'r':
 147                                 what |= 4;
 148                                 break;
 149                         case 'w':
 150                                 what |= 2;
 151                                 break;
 152                         case 'X':
 153                                 flags |= FLAG_X_KEEP;
 154                                 /* FALL THROUGH */
 155                         case 'x':
 156                                 what |= 1;
 157                                 break;
 158                         case 's':
 159                                 if (topbits)
 160                                         topoct |= topbits;
 161                                 else
 162                                         topoct = 04000;
 163                                 break;
 164                         case 't':
 165                                 topoct |= 01000;
 166                                 break;
 167                         default:
 168                                 state = STATE_ERROR;
 169                                 break;
 170                         }
 171                 }
 172                 modestr++;
 173         }
 174
 175         if (state == STATE_ERROR) {
 176                 free_chmod_mode(first_mode);
 177                 return NULL;
 178         }
 179
 180         if (!(curr_mode = *root_mode_ptr))
 181                 *root_mode_ptr = first_mode;
 182         else {
 183                 while (curr_mode->next)
 184                         curr_mode = curr_mode->next;
 185                 curr_mode->next = first_mode;
 186         }
 187
 188         return first_mode;
 189 }
 190
 191
 192 /* Takes an existing file permission and a list of AND/OR changes, and
 193  * create a new permissions. */
 194 int tweak_mode(int mode, struct chmod_mode_struct *chmod_modes)
 195 {
 196         int IsX = mode & 0111;
 197         int NonPerm = mode & ~CHMOD_BITS;
 198
 199         for ( ; chmod_modes; chmod_modes = chmod_modes->next) {
 200                 if ((chmod_modes->flags & FLAG_DIRS_ONLY) && !S_ISDIR(NonPerm))
 201                         continue;
 202                 if ((chmod_modes->flags & FLAG_FILES_ONLY) && S_ISDIR(NonPerm))
 203                         continue;
 204                 mode &= chmod_modes->ModeAND;
 205                 if ((chmod_modes->flags & FLAG_X_KEEP) && !IsX && !S_ISDIR(NonPerm))
 206                         mode |= chmod_modes->ModeOR & ~0111;
 207                 else
 208                         mode |= chmod_modes->ModeOR;
 209         }
 210
 211         return mode | NonPerm;
 212 }
 213
 214 /* Free the linked list created by parse_chmod. */
 215 int free_chmod_mode(struct chmod_mode_struct *chmod_modes)
 216 {
 217         struct chmod_mode_struct *next;
 218
 219         while (chmod_modes) {
 220                 next = chmod_modes->next;
 221                 free(chmod_modes);
 222                 chmod_modes = next;
 223         }
 224         return 0;
 225 }