cmd/mbr.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * cmd_mbr.c -- MBR (Master Boot Record) handling command
   4  *
   5  * Copyright (C) 2020 Samsung Electronics
   6  * author: Marek Szyprowski <m.szyprowski@samsung.com>
   7  *
   8  * based on the gpt command.
   9  */
  10
  11 #include <blk.h>
  12 #include <command.h>
  13 #include <malloc.h>
  14 #include <part.h>
  15 #include <vsprintf.h>
  16
  17 /**
  18  * extract_val() - Extract a value from the key=value pair list
  19  * @str: pointer to string with key=values pairs
  20  * @key: pointer to the key to search for
  21  *
  22  * The list of parameters is come separated, only a value for
  23  * the given key is returend.
  24  *
  25  * Function allocates memory for the value, remember to free!
  26  *
  27  * Return: Pointer to allocated string with the value.
  28  */
  29 static char *extract_val(const char *str, const char *key)
  30 {
  31         char *v, *k;
  32         char *s, *strcopy;
  33         char *new = NULL;
  34
  35         strcopy = strdup(str);
  36         if (strcopy == NULL)
  37                 return NULL;
  38
  39         s = strcopy;
  40         while (s) {
  41                 v = strsep(&s, ",");
  42                 if (!v)
  43                         break;
  44                 k = strsep(&v, "=");
  45                 if (!k)
  46                         break;
  47                 if  (strcmp(k, key) == 0) {
  48                         new = strdup(v);
  49                         break;
  50                 }
  51         }
  52
  53         free(strcopy);
  54
  55         return new;
  56 }
  57
  58 /**
  59  * found_key() - Search for a key without a value in the parameter list
  60  * @str: pointer to string with key
  61  * @key: pointer to the key to search for
  62  *
  63  * The list of parameters is come separated.
  64  *
  65  * Return: True if key has been found.
  66  */
  67 static bool found_key(const char *str, const char *key)
  68 {
  69         char *k;
  70         char *s, *strcopy;
  71         bool result = false;
  72
  73         strcopy = strdup(str);
  74         if (!strcopy)
  75                 return NULL;
  76
  77         s = strcopy;
  78         while (s) {
  79                 k = strsep(&s, ",");
  80                 if (!k)
  81                         break;
  82                 if  (strcmp(k, key) == 0) {
  83                         result = true;
  84                         break;
  85                 }
  86         }
  87
  88         free(strcopy);
  89
  90         return result;
  91 }
  92
  93 static int str_to_partitions(const char *str_part, int blksz,
  94         unsigned long *disk_uuid, struct disk_partition **partitions,
  95         int *parts_count)
  96 {
  97         char *tok, *str, *s;
  98         int i;
  99         char *val, *p;
 100         int p_count;
 101         struct disk_partition *parts;
 102         int errno = 0;
 103         uint64_t size_ll, start_ll;
 104
 105         if (str_part == NULL)
 106                 return -1;
 107
 108         str = strdup(str_part);
 109         if (str == NULL)
 110                 return -ENOMEM;
 111
 112         /* extract disk guid */
 113         s = str;
 114         val = extract_val(str, "uuid_disk");
 115         if (val) {
 116                 val = strsep(&val, ";");
 117                 p = val;
 118                 *disk_uuid = ustrtoull(p, &p, 0);
 119                 free(val);
 120                 /* Move s to first partition */
 121                 strsep(&s, ";");
 122         }
 123         if (s == NULL) {
 124                 printf("Error: is the partitions string NULL-terminated?\n");
 125                 return -EINVAL;
 126         }
 127
 128         /* remove the optional semicolon at the end of the string */
 129         i = strlen(s) - 1;
 130         if (s[i] == ';')
 131                 s[i] = '\0';
 132
 133         /* calculate expected number of partitions */
 134         p_count = 1;
 135         p = s;
 136         while (*p) {
 137                 if (*p++ == ';')
 138                         p_count++;
 139         }
 140
 141         /* allocate memory for partitions */
 142         parts = calloc(sizeof(struct disk_partition), p_count);
 143         if (parts == NULL)
 144                 return -ENOMEM;
 145
 146         /* retrieve partitions data from string */
 147         for (i = 0; i < p_count; i++) {
 148                 tok = strsep(&s, ";");
 149
 150                 if (tok == NULL)
 151                         break;
 152
 153                 /* size */
 154                 val = extract_val(tok, "size");
 155                 if (!val) { /* 'size' is mandatory */
 156                         errno = -4;
 157                         goto err;
 158                 }
 159                 p = val;
 160                 if ((strcmp(p, "-") == 0)) {
 161                         /* auto extend the size */
 162                         parts[i].size = 0;
 163                 } else {
 164                         size_ll = ustrtoull(p, &p, 0);
 165                         parts[i].size = size_ll / blksz;
 166                 }
 167                 free(val);
 168
 169                 /* start address */
 170                 val = extract_val(tok, "start");
 171                 if (val) { /* start address is optional */
 172                         p = val;
 173                         start_ll = ustrtoull(p, &p, 0);
 174                         parts[i].start = start_ll / blksz;
 175                         free(val);
 176                 }
 177
 178                 /* system id */
 179                 val = extract_val(tok, "id");
 180                 if (!val) { /* '' is mandatory */
 181                         errno = -4;
 182                         goto err;
 183                 }
 184                 p = val;
 185                 parts[i].sys_ind = ustrtoul(p, &p, 0);
 186                 free(val);
 187
 188                 /* bootable */
 189                 if (found_key(tok, "bootable"))
 190                         parts[i].bootable = PART_BOOTABLE;
 191         }
 192
 193         *parts_count = p_count;
 194         *partitions = parts;
 195         free(str);
 196
 197         return 0;
 198 err:
 199         free(str);
 200         free(parts);
 201
 202         return errno;
 203 }
 204
 205 static int do_write_mbr(struct blk_desc *dev, const char *str)
 206 {
 207         unsigned long disk_uuid = 0;
 208         struct disk_partition *partitions;
 209         int blksz = dev->blksz;
 210         int count;
 211
 212         if (str_to_partitions(str, blksz, &disk_uuid, &partitions, &count)) {
 213                 printf("MBR: failed to setup partitions from \"%s\"\n", str);
 214                 return -1;
 215         }
 216
 217         if (layout_mbr_partitions(partitions, count, dev->lba)) {
 218                 printf("MBR: failed to layout partitions on the device\n");
 219                 free(partitions);
 220                 return -1;
 221         }
 222
 223         if (write_mbr_partitions(dev, partitions, count, disk_uuid)) {
 224                 printf("MBR: failed to write partitions to the device\n");
 225                 free(partitions);
 226                 return -1;
 227         }
 228
 229         return 0;
 230 }
 231
 232 static int do_verify_mbr(struct blk_desc *dev, const char *str)
 233 {
 234         unsigned long disk_uuid = 0;
 235         struct disk_partition *partitions;
 236         int blksz = dev->blksz;
 237         int count, i, ret = 1;
 238
 239         if (str_to_partitions(str, blksz, &disk_uuid, &partitions, &count)) {
 240                 printf("MBR: failed to setup partitions from \"%s\"\n", str);
 241                 return -1;
 242         }
 243
 244         for (i = 0; i < count; i++) {
 245                 struct disk_partition p;
 246
 247                 if (part_get_info_by_type(dev, i + 1, PART_TYPE_DOS, &p))
 248                         goto fail;
 249
 250                 if ((partitions[i].size && p.size != partitions[i].size) ||
 251                     (partitions[i].start && p.start != partitions[i].start) ||
 252                     p.sys_ind != partitions[i].sys_ind)
 253                         goto fail;
 254         }
 255         ret = 0;
 256 fail:
 257         free(partitions);
 258         return ret;
 259 }
 260
 261 static int do_mbr(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 262 {
 263         const char *parts = NULL;
 264         int ret = CMD_RET_SUCCESS;
 265         int dev = 0;
 266         char *ep;
 267         struct blk_desc *blk_dev_desc = NULL;
 268
 269         if (argc != 4 && argc != 5)
 270                 return CMD_RET_USAGE;
 271
 272         dev = (int)dectoul(argv[3], &ep);
 273         if (!ep || ep[0] != '\0') {
 274                 printf("'%s' is not a number\n", argv[3]);
 275                 return CMD_RET_USAGE;
 276         }
 277         blk_dev_desc = blk_get_dev(argv[2], dev);
 278         if (!blk_dev_desc) {
 279                 printf("%s: %s dev %d NOT available\n",
 280                        __func__, argv[2], dev);
 281                 return CMD_RET_FAILURE;
 282         }
 283
 284         if ((strcmp(argv[1], "write") == 0)) {
 285                 parts = (argc == 5) ? argv[4] : env_get("mbr_parts");
 286                 printf("MBR: write ");
 287                 ret = do_write_mbr(blk_dev_desc, parts);
 288         } else if ((strcmp(argv[1], "verify") == 0)) {
 289                 printf("MBR: verify ");
 290                 parts = (argc == 5) ? argv[4] : env_get("mbr_parts");
 291                 ret = do_verify_mbr(blk_dev_desc, parts);
 292         } else {
 293                 return CMD_RET_USAGE;
 294         }
 295
 296         if (ret) {
 297                 printf("error!\n");
 298                 return CMD_RET_FAILURE;
 299         }
 300
 301         printf("success!\n");
 302         return CMD_RET_SUCCESS;
 303 }
 304
 305 U_BOOT_CMD(mbr, CONFIG_SYS_MAXARGS, 1, do_mbr,
 306         "MBR (Master Boot Record)",
 307         "<command> <interface> <dev> <partitions_list>\n"
 308         " - MBR partition table restoration utility\n"
 309         " Restore or check partition information on a device connected\n"
 310         " to the given block interface\n"
 311         " Example usage:\n"
 312         " mbr write mmc 0 [\"${mbr_parts}\"]\n"
 313         " mbr verify mmc 0 [\"${partitions}\"]\n"
 314 );