fs/hfsplus/options.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/hfsplus/options.c
   4  *
   5  * Copyright (C) 2001
   6  * Brad Boyer (flar@allandria.com)
   7  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   8  *
   9  * Option parsing
  10  */
  11
  12 #include <linux/string.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/parser.h>
  16 #include <linux/nls.h>
  17 #include <linux/mount.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/slab.h>
  20 #include "hfsplus_fs.h"
  21
  22 enum {
  23         opt_creator, opt_type,
  24         opt_umask, opt_uid, opt_gid,
  25         opt_part, opt_session, opt_nls,
  26         opt_nodecompose, opt_decompose,
  27         opt_barrier, opt_nobarrier,
  28         opt_force, opt_err
  29 };
  30
  31 static const match_table_t tokens = {
  32         { opt_creator, "creator=%s" },
  33         { opt_type, "type=%s" },
  34         { opt_umask, "umask=%o" },
  35         { opt_uid, "uid=%u" },
  36         { opt_gid, "gid=%u" },
  37         { opt_part, "part=%u" },
  38         { opt_session, "session=%u" },
  39         { opt_nls, "nls=%s" },
  40         { opt_decompose, "decompose" },
  41         { opt_nodecompose, "nodecompose" },
  42         { opt_barrier, "barrier" },
  43         { opt_nobarrier, "nobarrier" },
  44         { opt_force, "force" },
  45         { opt_err, NULL }
  46 };
  47
  48 /* Initialize an options object to reasonable defaults */
  49 void hfsplus_fill_defaults(struct hfsplus_sb_info *opts)
  50 {
  51         if (!opts)
  52                 return;
  53
  54         opts->creator = HFSPLUS_DEF_CR_TYPE;
  55         opts->type = HFSPLUS_DEF_CR_TYPE;
  56         opts->umask = current_umask();
  57         opts->uid = current_uid();
  58         opts->gid = current_gid();
  59         opts->part = -1;
  60         opts->session = -1;
  61 }
  62
  63 /* convert a "four byte character" to a 32 bit int with error checks */
  64 static inline int match_fourchar(substring_t *arg, u32 *result)
  65 {
  66         if (arg->to - arg->from != 4)
  67                 return -EINVAL;
  68         memcpy(result, arg->from, 4);
  69         return 0;
  70 }
  71
  72 int hfsplus_parse_options_remount(char *input, int *force)
  73 {
  74         char *p;
  75         substring_t args[MAX_OPT_ARGS];
  76         int token;
  77
  78         if (!input)
  79                 return 1;
  80
  81         while ((p = strsep(&input, ",")) != NULL) {
  82                 if (!*p)
  83                         continue;
  84
  85                 token = match_token(p, tokens, args);
  86                 switch (token) {
  87                 case opt_force:
  88                         *force = 1;
  89                         break;
  90                 default:
  91                         break;
  92                 }
  93         }
  94
  95         return 1;
  96 }
  97
  98 /* Parse options from mount. Returns 0 on failure */
  99 /* input is the options passed to mount() as a string */
 100 int hfsplus_parse_options(char *input, struct hfsplus_sb_info *sbi)
 101 {
 102         char *p;
 103         substring_t args[MAX_OPT_ARGS];
 104         int tmp, token;
 105
 106         if (!input)
 107                 goto done;
 108
 109         while ((p = strsep(&input, ",")) != NULL) {
 110                 if (!*p)
 111                         continue;
 112
 113                 token = match_token(p, tokens, args);
 114                 switch (token) {
 115                 case opt_creator:
 116                         if (match_fourchar(&args[0], &sbi->creator)) {
 117                                 pr_err("creator requires a 4 character value\n");
 118                                 return 0;
 119                         }
 120                         break;
 121                 case opt_type:
 122                         if (match_fourchar(&args[0], &sbi->type)) {
 123                                 pr_err("type requires a 4 character value\n");
 124                                 return 0;
 125                         }
 126                         break;
 127                 case opt_umask:
 128                         if (match_octal(&args[0], &tmp)) {
 129                                 pr_err("umask requires a value\n");
 130                                 return 0;
 131                         }
 132                         sbi->umask = (umode_t)tmp;
 133                         break;
 134                 case opt_uid:
 135                         if (match_int(&args[0], &tmp)) {
 136                                 pr_err("uid requires an argument\n");
 137                                 return 0;
 138                         }
 139                         sbi->uid = make_kuid(current_user_ns(), (uid_t)tmp);
 140                         if (!uid_valid(sbi->uid)) {
 141                                 pr_err("invalid uid specified\n");
 142                                 return 0;
 143                         } else {
 144                                 set_bit(HFSPLUS_SB_UID, &sbi->flags);
 145                         }
 146                         break;
 147                 case opt_gid:
 148                         if (match_int(&args[0], &tmp)) {
 149                                 pr_err("gid requires an argument\n");
 150                                 return 0;
 151                         }
 152                         sbi->gid = make_kgid(current_user_ns(), (gid_t)tmp);
 153                         if (!gid_valid(sbi->gid)) {
 154                                 pr_err("invalid gid specified\n");
 155                                 return 0;
 156                         } else {
 157                                 set_bit(HFSPLUS_SB_GID, &sbi->flags);
 158                         }
 159                         break;
 160                 case opt_part:
 161                         if (match_int(&args[0], &sbi->part)) {
 162                                 pr_err("part requires an argument\n");
 163                                 return 0;
 164                         }
 165                         break;
 166                 case opt_session:
 167                         if (match_int(&args[0], &sbi->session)) {
 168                                 pr_err("session requires an argument\n");
 169                                 return 0;
 170                         }
 171                         break;
 172                 case opt_nls:
 173                         if (sbi->nls) {
 174                                 pr_err("unable to change nls mapping\n");
 175                                 return 0;
 176                         }
 177                         p = match_strdup(&args[0]);
 178                         if (p)
 179                                 sbi->nls = load_nls(p);
 180                         if (!sbi->nls) {
 181                                 pr_err("unable to load nls mapping \"%s\"\n",
 182                                        p);
 183                                 kfree(p);
 184                                 return 0;
 185                         }
 186                         kfree(p);
 187                         break;
 188                 case opt_decompose:
 189                         clear_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
 190                         break;
 191                 case opt_nodecompose:
 192                         set_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
 193                         break;
 194                 case opt_barrier:
 195                         clear_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
 196                         break;
 197                 case opt_nobarrier:
 198                         set_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
 199                         break;
 200                 case opt_force:
 201                         set_bit(HFSPLUS_SB_FORCE, &sbi->flags);
 202                         break;
 203                 default:
 204                         return 0;
 205                 }
 206         }
 207
 208 done:
 209         if (!sbi->nls) {
 210                 /* try utf8 first, as this is the old default behaviour */
 211                 sbi->nls = load_nls("utf8");
 212                 if (!sbi->nls)
 213                         sbi->nls = load_nls_default();
 214                 if (!sbi->nls)
 215                         return 0;
 216         }
 217
 218         return 1;
 219 }
 220
 221 int hfsplus_show_options(struct seq_file *seq, struct dentry *root)
 222 {
 223         struct hfsplus_sb_info *sbi = HFSPLUS_SB(root->d_sb);
 224
 225         if (sbi->creator != HFSPLUS_DEF_CR_TYPE)
 226                 seq_show_option_n(seq, "creator", (char *)&sbi->creator, 4);
 227         if (sbi->type != HFSPLUS_DEF_CR_TYPE)
 228                 seq_show_option_n(seq, "type", (char *)&sbi->type, 4);
 229         seq_printf(seq, ",umask=%o,uid=%u,gid=%u", sbi->umask,
 230                         from_kuid_munged(&init_user_ns, sbi->uid),
 231                         from_kgid_munged(&init_user_ns, sbi->gid));
 232         if (sbi->part >= 0)
 233                 seq_printf(seq, ",part=%u", sbi->part);
 234         if (sbi->session >= 0)
 235                 seq_printf(seq, ",session=%u", sbi->session);
 236         if (sbi->nls)
 237                 seq_printf(seq, ",nls=%s", sbi->nls->charset);
 238         if (test_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags))
 239                 seq_puts(seq, ",nodecompose");
 240         if (test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
 241                 seq_puts(seq, ",nobarrier");
 242         return 0;
 243 }