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                         }
 144                         break;
 145                 case opt_gid:
 146                         if (match_int(&args[0], &tmp)) {
 147                                 pr_err("gid requires an argument\n");
 148                                 return 0;
 149                         }
 150                         sbi->gid = make_kgid(current_user_ns(), (gid_t)tmp);
 151                         if (!gid_valid(sbi->gid)) {
 152                                 pr_err("invalid gid specified\n");
 153                                 return 0;
 154                         }
 155                         break;
 156                 case opt_part:
 157                         if (match_int(&args[0], &sbi->part)) {
 158                                 pr_err("part requires an argument\n");
 159                                 return 0;
 160                         }
 161                         break;
 162                 case opt_session:
 163                         if (match_int(&args[0], &sbi->session)) {
 164                                 pr_err("session requires an argument\n");
 165                                 return 0;
 166                         }
 167                         break;
 168                 case opt_nls:
 169                         if (sbi->nls) {
 170                                 pr_err("unable to change nls mapping\n");
 171                                 return 0;
 172                         }
 173                         p = match_strdup(&args[0]);
 174                         if (p)
 175                                 sbi->nls = load_nls(p);
 176                         if (!sbi->nls) {
 177                                 pr_err("unable to load nls mapping \"%s\"\n",
 178                                        p);
 179                                 kfree(p);
 180                                 return 0;
 181                         }
 182                         kfree(p);
 183                         break;
 184                 case opt_decompose:
 185                         clear_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
 186                         break;
 187                 case opt_nodecompose:
 188                         set_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
 189                         break;
 190                 case opt_barrier:
 191                         clear_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
 192                         break;
 193                 case opt_nobarrier:
 194                         set_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags);
 195                         break;
 196                 case opt_force:
 197                         set_bit(HFSPLUS_SB_FORCE, &sbi->flags);
 198                         break;
 199                 default:
 200                         return 0;
 201                 }
 202         }
 203
 204 done:
 205         if (!sbi->nls) {
 206                 /* try utf8 first, as this is the old default behaviour */
 207                 sbi->nls = load_nls("utf8");
 208                 if (!sbi->nls)
 209                         sbi->nls = load_nls_default();
 210                 if (!sbi->nls)
 211                         return 0;
 212         }
 213
 214         return 1;
 215 }
 216
 217 int hfsplus_show_options(struct seq_file *seq, struct dentry *root)
 218 {
 219         struct hfsplus_sb_info *sbi = HFSPLUS_SB(root->d_sb);
 220
 221         if (sbi->creator != HFSPLUS_DEF_CR_TYPE)
 222                 seq_show_option_n(seq, "creator", (char *)&sbi->creator, 4);
 223         if (sbi->type != HFSPLUS_DEF_CR_TYPE)
 224                 seq_show_option_n(seq, "type", (char *)&sbi->type, 4);
 225         seq_printf(seq, ",umask=%o,uid=%u,gid=%u", sbi->umask,
 226                         from_kuid_munged(&init_user_ns, sbi->uid),
 227                         from_kgid_munged(&init_user_ns, sbi->gid));
 228         if (sbi->part >= 0)
 229                 seq_printf(seq, ",part=%u", sbi->part);
 230         if (sbi->session >= 0)
 231                 seq_printf(seq, ",session=%u", sbi->session);
 232         if (sbi->nls)
 233                 seq_printf(seq, ",nls=%s", sbi->nls->charset);
 234         if (test_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags))
 235                 seq_puts(seq, ",nodecompose");
 236         if (test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
 237                 seq_puts(seq, ",nobarrier");
 238         return 0;
 239 }