cmds-property.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public
   4  * License v2 as published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   9  * General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public
  12  * License along with this program; if not, write to the
  13  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14  * Boston, MA 021110-1307, USA.
  15  */
  16
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <stdio.h>
  20 #include <unistd.h>
  21 #include <fcntl.h>
  22 #include <sys/ioctl.h>
  23 #include <sys/stat.h>
  24
  25 #include "commands.h"
  26 #include "props.h"
  27 #include "ctree.h"
  28 #include "utils.h"
  29
  30 static const char * const property_cmd_group_usage[] = {
  31         "btrfs property get/set/list [-t <type>] <object> [<name>] [value]",
  32         NULL
  33 };
  34
  35 static int parse_prop(const char *arg, const struct prop_handler *props,
  36                       const struct prop_handler **prop_ret)
  37 {
  38         const struct prop_handler *prop = props;
  39
  40         for (; prop->name; prop++) {
  41                 if (!strcmp(prop->name, arg)) {
  42                         *prop_ret = prop;
  43                         return 0;
  44                 }
  45         }
  46
  47         return -1;
  48 }
  49
  50 static int get_fsid(const char *path, u8 *fsid, int silent)
  51 {
  52         int ret;
  53         int fd;
  54         struct btrfs_ioctl_fs_info_args args;
  55
  56         fd = open(path, O_RDONLY);
  57         if (fd < 0) {
  58                 ret = -errno;
  59                 if (!silent)
  60                         error("failed to open %s: %s", path,
  61                                 strerror(-ret));
  62                 goto out;
  63         }
  64
  65         ret = ioctl(fd, BTRFS_IOC_FS_INFO, &args);
  66         if (ret < 0) {
  67                 ret = -errno;
  68                 goto out;
  69         }
  70
  71         memcpy(fsid, args.fsid, BTRFS_FSID_SIZE);
  72         ret = 0;
  73
  74 out:
  75         if (fd != -1)
  76                 close(fd);
  77         return ret;
  78 }
  79
  80 static int check_btrfs_object(const char *object)
  81 {
  82         int ret;
  83         u8 fsid[BTRFS_FSID_SIZE];
  84
  85         ret = get_fsid(object, fsid, 0);
  86         if (ret < 0)
  87                 ret = 0;
  88         else
  89                 ret = 1;
  90         return ret;
  91 }
  92
  93 static int check_is_root(const char *object)
  94 {
  95         int ret;
  96         u8 fsid[BTRFS_FSID_SIZE];
  97         u8 fsid2[BTRFS_FSID_SIZE];
  98         char *tmp = NULL;
  99         char *rp;
 100
 101         rp = realpath(object, NULL);
 102         if (!rp) {
 103                 ret = -errno;
 104                 goto out;
 105         }
 106         if (!strcmp(rp, "/")) {
 107                 ret = 0;
 108                 goto out;
 109         }
 110
 111         tmp = malloc(strlen(object) + 5);
 112         if (!tmp) {
 113                 ret = -ENOMEM;
 114                 goto out;
 115         }
 116         strcpy(tmp, object);
 117         if (tmp[strlen(tmp) - 1] != '/')
 118                 strcat(tmp, "/");
 119         strcat(tmp, "..");
 120
 121         ret = get_fsid(object, fsid, 0);
 122         if (ret < 0) {
 123                 error("get_fsid for %s failed: %s", object, strerror(-ret));
 124                 goto out;
 125         }
 126
 127         ret = get_fsid(tmp, fsid2, 1);
 128         if (ret == -ENOTTY) {
 129                 ret = 0;
 130                 goto out;
 131         } else if (ret == -ENOTDIR) {
 132                 ret = 1;
 133                 goto out;
 134         } else if (ret < 0) {
 135                 error("get_fsid for %s failed: %s", tmp, strerror(-ret));
 136                 goto out;
 137         }
 138
 139         if (memcmp(fsid, fsid2, BTRFS_FSID_SIZE)) {
 140                 ret = 0;
 141                 goto out;
 142         }
 143
 144         ret = 1;
 145
 146 out:
 147         free(tmp);
 148         free(rp);
 149         return ret;
 150 }
 151
 152 static int count_bits(int v)
 153 {
 154         unsigned int tmp = (unsigned int)v;
 155         int cnt = 0;
 156
 157         while (tmp) {
 158                 if (tmp & 1)
 159                         cnt++;
 160                 tmp >>= 1;
 161         }
 162         return cnt;
 163 }
 164
 165 static int autodetect_object_types(const char *object, int *types_out)
 166 {
 167         int ret;
 168         int is_btrfs_object;
 169         int types = 0;
 170         struct stat st;
 171
 172         is_btrfs_object = check_btrfs_object(object);
 173
 174         ret = lstat(object, &st);
 175         if (ret < 0) {
 176                 ret = -errno;
 177                 goto out;
 178         }
 179
 180         if (is_btrfs_object) {
 181                 types |= prop_object_inode;
 182                 if (st.st_ino == BTRFS_FIRST_FREE_OBJECTID)
 183                         types |= prop_object_subvol;
 184
 185                 ret = check_is_root(object);
 186                 if (ret < 0)
 187                         goto out;
 188                 if (!ret)
 189                         types |= prop_object_root;
 190         }
 191
 192         if (S_ISBLK(st.st_mode))
 193                 types |= prop_object_dev;
 194
 195         ret = 0;
 196         *types_out = types;
 197
 198 out:
 199         return ret;
 200 }
 201
 202 static int print_prop_help(const struct prop_handler *prop)
 203 {
 204         fprintf(stdout, "%-20s%s\n", prop->name, prop->desc);
 205         return 0;
 206 }
 207
 208 static int dump_prop(const struct prop_handler *prop,
 209                      const char *object,
 210                      int types,
 211                      int type,
 212                      int name_and_help)
 213 {
 214         int ret = 0;
 215
 216         if ((types & type) && (prop->types & type)) {
 217                 if (!name_and_help)
 218                         ret = prop->handler(type, object, prop->name, NULL);
 219                 else
 220                         ret = print_prop_help(prop);
 221         }
 222         return ret;
 223 }
 224
 225 static int dump_props(int types, const char *object, int name_and_help)
 226 {
 227         int ret;
 228         int i;
 229         int j;
 230         const struct prop_handler *prop;
 231
 232         for (i = 0; prop_handlers[i].name; i++) {
 233                 prop = &prop_handlers[i];
 234                 for (j = 1; j < __prop_object_max; j <<= 1) {
 235                         ret = dump_prop(prop, object, types, j, name_and_help);
 236                         if (ret < 0) {
 237                                 ret = 50;
 238                                 goto out;
 239                         }
 240                 }
 241         }
 242
 243         ret = 0;
 244
 245 out:
 246         return ret;
 247 }
 248
 249 static int setget_prop(int types, const char *object,
 250                        const char *name, const char *value)
 251 {
 252         int ret;
 253         const struct prop_handler *prop = NULL;
 254
 255         ret = parse_prop(name, prop_handlers, &prop);
 256         if (ret == -1) {
 257                 error("unknown property: %s", name);
 258                 ret = 40;
 259                 goto out;
 260         }
 261
 262         types &= prop->types;
 263         if (!types) {
 264                 error("object is not compatible with property: %s", prop->name);
 265                 ret = 47;
 266                 goto out;
 267         }
 268
 269         if (count_bits(types) > 1) {
 270                 error("type of object is ambiguous, please use option -t");
 271                 ret = 48;
 272                 goto out;
 273         }
 274
 275         if (value && prop->read_only) {
 276                 error("property is read-only property: %s",
 277                                 prop->name);
 278                 ret = 51;
 279                 goto out;
 280         }
 281
 282         ret = prop->handler(types, object, name, value);
 283
 284         if (ret < 0)
 285                 ret = 50;
 286         else
 287                 ret = 0;
 288
 289 out:
 290         return ret;
 291
 292 }
 293
 294 static void parse_args(int argc, char **argv,
 295                        const char * const *usage_str,
 296                        int *types, char **object,
 297                        char **name, char **value, int min_nonopt_args)
 298 {
 299         int ret;
 300         char *type_str = NULL;
 301         int max_nonopt_args = 1;
 302
 303         optind = 1;
 304         while (1) {
 305                 int c = getopt(argc, argv, "t:");
 306                 if (c < 0)
 307                         break;
 308
 309                 switch (c) {
 310                 case 't':
 311                         type_str = optarg;
 312                         break;
 313                 default:
 314                         usage(usage_str);
 315                 }
 316         }
 317
 318         if (name)
 319                 max_nonopt_args++;
 320         if (value)
 321                 max_nonopt_args++;
 322
 323         if (check_argc_min(argc - optind, min_nonopt_args) ||
 324             check_argc_max(argc - optind, max_nonopt_args))
 325                 usage(usage_str);
 326
 327         *types = 0;
 328         if (type_str) {
 329                 if (!strcmp(type_str, "s") || !strcmp(type_str, "subvol")) {
 330                         *types = prop_object_subvol;
 331                 } else if (!strcmp(type_str, "f") ||
 332                            !strcmp(type_str, "filesystem")) {
 333                         *types = prop_object_root;
 334                 } else if (!strcmp(type_str, "i") ||
 335                            !strcmp(type_str, "inode")) {
 336                         *types = prop_object_inode;
 337                 } else if (!strcmp(type_str, "d") ||
 338                            !strcmp(type_str, "device")) {
 339                         *types = prop_object_dev;
 340                 } else {
 341                         error("invalid object type: %s", type_str);
 342                         usage(usage_str);
 343                 }
 344         }
 345
 346         *object = argv[optind++];
 347         if (optind < argc)
 348                 *name = argv[optind++];
 349         if (optind < argc)
 350                 *value = argv[optind++];
 351
 352         if (!*types) {
 353                 ret = autodetect_object_types(*object, types);
 354                 if (ret < 0) {
 355                         error("failed to detect object type: %s",
 356                                 strerror(-ret));
 357                         usage(usage_str);
 358                 }
 359                 if (!*types) {
 360                         error("object is not a btrfs object: %s", *object);
 361                         usage(usage_str);
 362                 }
 363         }
 364 }
 365
 366 static const char * const cmd_property_get_usage[] = {
 367         "btrfs property get [-t <type>] <object> [<name>]",
 368         "Gets a property from a btrfs object.",
 369         "If no name is specified, all properties for the given object are",
 370         "printed.",
 371         "A filesystem object can be a the filesystem itself, a subvolume,",
 372         "an inode or a device. The '-t <type>' option can be used to explicitly",
 373         "specify what type of object you meant. This is only needed when a",
 374         "property could be set for more then one object type. Possible types",
 375         "are s[ubvol], f[ilesystem], i[node] and d[evice].",
 376         NULL
 377 };
 378
 379 static int cmd_property_get(int argc, char **argv)
 380 {
 381         int ret;
 382         char *object = NULL;
 383         char *name = NULL;
 384         int types = 0;
 385
 386         parse_args(argc, argv, cmd_property_get_usage, &types, &object, &name,
 387                    NULL, 1);
 388
 389         if (name)
 390                 ret = setget_prop(types, object, name, NULL);
 391         else
 392                 ret = dump_props(types, object, 0);
 393
 394         return ret;
 395 }
 396
 397 static const char * const cmd_property_set_usage[] = {
 398         "btrfs property set [-t <type>] <object> <name> <value>",
 399         "Sets a property on a btrfs object.",
 400         "Please see the help of 'btrfs property get' for a description of",
 401         "objects and object types.",
 402         NULL
 403 };
 404
 405 static int cmd_property_set(int argc, char **argv)
 406 {
 407         int ret;
 408         char *object = NULL;
 409         char *name = NULL;
 410         char *value = NULL;
 411         int types = 0;
 412
 413         parse_args(argc, argv, cmd_property_set_usage, &types,
 414                    &object, &name, &value, 3);
 415
 416         ret = setget_prop(types, object, name, value);
 417
 418         return ret;
 419 }
 420
 421 static const char * const cmd_property_list_usage[] = {
 422         "btrfs property list [-t <type>] <object>",
 423         "Lists available properties with their descriptions for the given object.",
 424         "Please see the help of 'btrfs property get' for a description of",
 425         "objects and object types.",
 426         NULL
 427 };
 428
 429 static int cmd_property_list(int argc, char **argv)
 430 {
 431         int ret;
 432         char *object = NULL;
 433         int types = 0;
 434
 435         parse_args(argc, argv, cmd_property_list_usage,
 436                    &types, &object, NULL, NULL, 1);
 437
 438         ret = dump_props(types, object, 1);
 439
 440         return ret;
 441 }
 442
 443 static const char property_cmd_group_info[] =
 444 "modify properties of filesystem objects";
 445
 446 const struct cmd_group property_cmd_group = {
 447         property_cmd_group_usage, property_cmd_group_info, {
 448                 { "get", cmd_property_get,
 449                         cmd_property_get_usage, NULL, 0 },
 450                 { "set", cmd_property_set,
 451                         cmd_property_set_usage, NULL, 0 },
 452                 { "list", cmd_property_list,
 453                         cmd_property_list_usage, NULL, 0 },
 454                 NULL_CMD_STRUCT
 455         }
 456 };
 457
 458 int cmd_property(int argc, char **argv)
 459 {
 460         return handle_command_group(&property_cmd_group, argc, argv);
 461 }