lib/exfat_fs.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   Copyright (C) 2021 LG Electronics.
   4  *
   5  *   Author(s): Hyunchul Lee <hyc.lee@gmail.com>
   6  */
   7
   8 #include <stdlib.h>
   9 #include <stdio.h>
  10 #include <string.h>
  11 #include <errno.h>
  12
  13 #include "exfat_ondisk.h"
  14 #include "libexfat.h"
  15
  16 #include "exfat_fs.h"
  17 #include "exfat_dir.h"
  18
  19 struct exfat_inode *exfat_alloc_inode(__u16 attr)
  20 {
  21         struct exfat_inode *node;
  22         int size;
  23
  24         size = offsetof(struct exfat_inode, name) + NAME_BUFFER_SIZE;
  25         node = calloc(1, size);
  26         if (!node) {
  27                 exfat_err("failed to allocate exfat_node\n");
  28                 return NULL;
  29         }
  30
  31         node->parent = NULL;
  32         INIT_LIST_HEAD(&node->children);
  33         INIT_LIST_HEAD(&node->sibling);
  34         INIT_LIST_HEAD(&node->list);
  35
  36         node->attr = attr;
  37         return node;
  38 }
  39
  40 void exfat_free_inode(struct exfat_inode *node)
  41 {
  42         if (node) {
  43                 if (node->dentry_set)
  44                         free(node->dentry_set);
  45                 free(node);
  46         }
  47 }
  48
  49 void exfat_free_children(struct exfat_inode *dir, bool file_only)
  50 {
  51         struct exfat_inode *node, *i;
  52
  53         list_for_each_entry_safe(node, i, &dir->children, sibling) {
  54                 if (file_only) {
  55                         if (!(node->attr & ATTR_SUBDIR)) {
  56                                 list_del(&node->sibling);
  57                                 exfat_free_inode(node);
  58                         }
  59                 } else {
  60                         list_del(&node->sibling);
  61                         list_del(&node->list);
  62                         exfat_free_inode(node);
  63                 }
  64         }
  65 }
  66
  67 void exfat_free_file_children(struct exfat_inode *dir)
  68 {
  69         exfat_free_children(dir, true);
  70 }
  71
  72 /* delete @child and all ancestors that does not have
  73  * children
  74  */
  75 void exfat_free_ancestors(struct exfat_inode *child)
  76 {
  77         struct exfat_inode *parent;
  78
  79         while (child && list_empty(&child->children)) {
  80                 if (!child->parent || !(child->attr & ATTR_SUBDIR))
  81                         return;
  82
  83                 parent = child->parent;
  84                 list_del(&child->sibling);
  85                 exfat_free_inode(child);
  86
  87                 child = parent;
  88         }
  89         return;
  90 }
  91
  92 void exfat_free_dir_list(struct exfat *exfat)
  93 {
  94         struct exfat_inode *dir, *i;
  95
  96         list_for_each_entry_safe(dir, i, &exfat->dir_list, list) {
  97                 if (!dir->parent)
  98                         continue;
  99                 exfat_free_file_children(dir);
 100                 list_del(&dir->list);
 101                 exfat_free_inode(dir);
 102         }
 103 }
 104
 105 void exfat_free_exfat(struct exfat *exfat)
 106 {
 107         if (exfat) {
 108                 if (exfat->bs)
 109                         free(exfat->bs);
 110                 if (exfat->alloc_bitmap)
 111                         free(exfat->alloc_bitmap);
 112                 if (exfat->disk_bitmap)
 113                         free(exfat->disk_bitmap);
 114                 if (exfat->ohead_bitmap)
 115                         free(exfat->ohead_bitmap);
 116                 if (exfat->upcase_table)
 117                         free(exfat->upcase_table);
 118                 if (exfat->root)
 119                         exfat_free_inode(exfat->root);
 120                 if (exfat->lookup_buffer)
 121                         free(exfat->lookup_buffer);
 122                 free(exfat);
 123         }
 124 }
 125
 126 struct exfat *exfat_alloc_exfat(struct exfat_blk_dev *blk_dev, struct pbr *bs)
 127 {
 128         struct exfat *exfat;
 129
 130         exfat = calloc(1, sizeof(*exfat));
 131         if (!exfat) {
 132                 free(bs);
 133                 return NULL;
 134         }
 135
 136         INIT_LIST_HEAD(&exfat->dir_list);
 137         exfat->blk_dev = blk_dev;
 138         exfat->bs = bs;
 139         exfat->clus_count = le32_to_cpu(bs->bsx.clu_count);
 140         exfat->clus_size = EXFAT_CLUSTER_SIZE(bs);
 141         exfat->sect_size = EXFAT_SECTOR_SIZE(bs);
 142
 143         /* TODO: bitmap could be very large. */
 144         exfat->alloc_bitmap = calloc(1, EXFAT_BITMAP_SIZE(exfat->clus_count));
 145         if (!exfat->alloc_bitmap) {
 146                 exfat_err("failed to allocate bitmap\n");
 147                 goto err;
 148         }
 149
 150         exfat->ohead_bitmap = calloc(1, EXFAT_BITMAP_SIZE(exfat->clus_count));
 151         if (!exfat->ohead_bitmap) {
 152                 exfat_err("failed to allocate bitmap\n");
 153                 goto err;
 154         }
 155
 156         exfat->disk_bitmap = calloc(1, EXFAT_BITMAP_SIZE(exfat->clus_count));
 157         if (!exfat->disk_bitmap) {
 158                 exfat_err("failed to allocate bitmap\n");
 159                 goto err;
 160         }
 161
 162         exfat->buffer_count = ((MAX_EXT_DENTRIES + 1) * DENTRY_SIZE) /
 163                 exfat_get_read_size(exfat) + 1;
 164
 165         exfat->start_clu = EXFAT_FIRST_CLUSTER;
 166         return exfat;
 167 err:
 168         exfat_free_exfat(exfat);
 169         return NULL;
 170 }
 171
 172 struct buffer_desc *exfat_alloc_buffer(struct exfat *exfat)
 173 {
 174         struct buffer_desc *bd;
 175         unsigned int i;
 176         unsigned int read_size = exfat_get_read_size(exfat);
 177
 178         bd = calloc(exfat->buffer_count, sizeof(*bd));
 179         if (!bd)
 180                 return NULL;
 181
 182         for (i = 0; i < exfat->buffer_count; i++) {
 183                 bd[i].buffer = malloc(read_size);
 184                 if (!bd[i].buffer)
 185                         goto err;
 186
 187                 memset(&bd[i].dirty, 0, sizeof(bd[i].dirty));
 188         }
 189         return bd;
 190 err:
 191         exfat_free_buffer(exfat, bd);
 192         return NULL;
 193 }
 194
 195 void exfat_free_buffer(const struct exfat *exfat, struct buffer_desc *bd)
 196 {
 197         unsigned int i;
 198
 199         for (i = 0; i < exfat->buffer_count; i++) {
 200                 if (bd[i].buffer)
 201                         free(bd[i].buffer);
 202         }
 203         free(bd);
 204 }
 205
 206 /*
 207  * get references of ancestors that include @child until the count of
 208  * ancesters is not larger than @count and the count of characters of
 209  * their names is not larger than @max_char_len.
 210  * return true if root is reached.
 211  */
 212 static bool get_ancestors(struct exfat_inode *child,
 213                           struct exfat_inode **ancestors, int count,
 214                           int max_char_len,
 215                           int *ancestor_count)
 216 {
 217         struct exfat_inode *dir;
 218         int name_len, char_len;
 219         int root_depth, depth, i;
 220
 221         root_depth = 0;
 222         char_len = 0;
 223         max_char_len += 1;
 224
 225         dir = child;
 226         while (dir) {
 227                 name_len = exfat_utf16_len(dir->name, NAME_BUFFER_SIZE);
 228                 if (char_len + name_len > max_char_len)
 229                         break;
 230
 231                 /* include '/' */
 232                 char_len += name_len + 1;
 233                 root_depth++;
 234
 235                 dir = dir->parent;
 236         }
 237
 238         depth = MIN(root_depth, count);
 239
 240         for (dir = child, i = depth - 1; i >= 0; dir = dir->parent, i--)
 241                 ancestors[i] = dir;
 242
 243         *ancestor_count = depth;
 244         return !dir;
 245 }
 246
 247 int exfat_resolve_path(struct path_resolve_ctx *ctx, struct exfat_inode *child)
 248 {
 249         int depth, i;
 250         int name_len;
 251         __le16 *utf16_path;
 252         static const __le16 utf16_slash = cpu_to_le16(0x002F);
 253         static const __le16 utf16_null = cpu_to_le16(0x0000);
 254         size_t in_size;
 255
 256         ctx->local_path[0] = '\0';
 257
 258         get_ancestors(child,
 259                       ctx->ancestors,
 260                       sizeof(ctx->ancestors) / sizeof(ctx->ancestors[0]),
 261                       PATH_MAX,
 262                       &depth);
 263
 264         utf16_path = ctx->utf16_path;
 265         for (i = 0; i < depth; i++) {
 266                 name_len = exfat_utf16_len(ctx->ancestors[i]->name,
 267                                            NAME_BUFFER_SIZE);
 268                 memcpy((char *)utf16_path, (char *)ctx->ancestors[i]->name,
 269                        name_len * 2);
 270                 utf16_path += name_len;
 271                 memcpy((char *)utf16_path, &utf16_slash, sizeof(utf16_slash));
 272                 utf16_path++;
 273         }
 274
 275         if (depth > 1)
 276                 utf16_path--;
 277         memcpy((char *)utf16_path, &utf16_null, sizeof(utf16_null));
 278         utf16_path++;
 279
 280         in_size = (utf16_path - ctx->utf16_path) * sizeof(__le16);
 281         return exfat_utf16_dec(ctx->utf16_path, in_size,
 282                                 ctx->local_path, sizeof(ctx->local_path));
 283 }
 284
 285 int exfat_resolve_path_parent(struct path_resolve_ctx *ctx,
 286                               struct exfat_inode *parent, struct exfat_inode *child)
 287 {
 288         int ret;
 289         struct exfat_inode *old;
 290
 291         old = child->parent;
 292         child->parent = parent;
 293
 294         ret = exfat_resolve_path(ctx, child);
 295         child->parent = old;
 296         return ret;
 297 }