src/dissect/dissect.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2016 Lennart Poettering
   6 ***/
   7
   8 #include <fcntl.h>
   9 #include <stdio.h>
  10 #include <getopt.h>
  11
  12 #include "architecture.h"
  13 #include "dissect-image.h"
  14 #include "hexdecoct.h"
  15 #include "log.h"
  16 #include "loop-util.h"
  17 #include "string-util.h"
  18 #include "strv.h"
  19 #include "user-util.h"
  20 #include "util.h"
  21
  22 static enum {
  23         ACTION_DISSECT,
  24         ACTION_MOUNT,
  25 } arg_action = ACTION_DISSECT;
  26 static const char *arg_image = NULL;
  27 static const char *arg_path = NULL;
  28 static DissectImageFlags arg_flags = DISSECT_IMAGE_REQUIRE_ROOT|DISSECT_IMAGE_DISCARD_ON_LOOP;
  29 static void *arg_root_hash = NULL;
  30 static size_t arg_root_hash_size = 0;
  31
  32 static void help(void) {
  33         printf("%s [OPTIONS...] IMAGE\n"
  34                "%s [OPTIONS...] --mount IMAGE PATH\n"
  35                "Dissect a file system OS image.\n\n"
  36                "  -h --help            Show this help\n"
  37                "     --version         Show package version\n"
  38                "  -m --mount           Mount the image to the specified directory\n"
  39                "  -r --read-only       Mount read-only\n"
  40                "     --discard=MODE    Choose 'discard' mode (disabled, loop, all, crypto)\n"
  41                "     --root-hash=HASH  Specify root hash for verity\n",
  42                program_invocation_short_name,
  43                program_invocation_short_name);
  44 }
  45
  46 static int parse_argv(int argc, char *argv[]) {
  47
  48         enum {
  49                 ARG_VERSION = 0x100,
  50                 ARG_DISCARD,
  51                 ARG_ROOT_HASH,
  52         };
  53
  54         static const struct option options[] = {
  55                 { "help",      no_argument,       NULL, 'h'           },
  56                 { "version",   no_argument,       NULL, ARG_VERSION   },
  57                 { "mount",     no_argument,       NULL, 'm'           },
  58                 { "read-only", no_argument,       NULL, 'r'           },
  59                 { "discard",   required_argument, NULL, ARG_DISCARD   },
  60                 { "root-hash", required_argument, NULL, ARG_ROOT_HASH },
  61                 {}
  62         };
  63
  64         int c, r;
  65
  66         assert(argc >= 0);
  67         assert(argv);
  68
  69         while ((c = getopt_long(argc, argv, "hmr", options, NULL)) >= 0) {
  70
  71                 switch (c) {
  72
  73                 case 'h':
  74                         help();
  75                         return 0;
  76
  77                 case ARG_VERSION:
  78                         return version();
  79
  80                 case 'm':
  81                         arg_action = ACTION_MOUNT;
  82                         break;
  83
  84                 case 'r':
  85                         arg_flags |= DISSECT_IMAGE_READ_ONLY;
  86                         break;
  87
  88                 case ARG_DISCARD: {
  89                         DissectImageFlags flags;
  90
  91                         if (streq(optarg, "disabled"))
  92                                 flags = 0;
  93                         else if (streq(optarg, "loop"))
  94                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP;
  95                         else if (streq(optarg, "all"))
  96                                 flags = DISSECT_IMAGE_DISCARD_ON_LOOP | DISSECT_IMAGE_DISCARD;
  97                         else if (streq(optarg, "crypt"))
  98                                 flags = DISSECT_IMAGE_DISCARD_ANY;
  99                         else {
 100                                 log_error("Unknown --discard= parameter: %s", optarg);
 101                                 return -EINVAL;
 102                         }
 103                         arg_flags = (arg_flags & ~DISSECT_IMAGE_DISCARD_ANY) | flags;
 104
 105                         break;
 106                 }
 107
 108                 case ARG_ROOT_HASH: {
 109                         void *p;
 110                         size_t l;
 111
 112                         r = unhexmem(optarg, strlen(optarg), &p, &l);
 113                         if (r < 0)
 114                                 return log_error_errno(r, "Failed to parse root hash: %s", optarg);
 115                         if (l < sizeof(sd_id128_t)) {
 116                                 log_error("Root hash must be at least 128bit long: %s", optarg);
 117                                 free(p);
 118                                 return -EINVAL;
 119                         }
 120
 121                         free(arg_root_hash);
 122                         arg_root_hash = p;
 123                         arg_root_hash_size = l;
 124                         break;
 125                 }
 126
 127                 case '?':
 128                         return -EINVAL;
 129
 130                 default:
 131                         assert_not_reached("Unhandled option");
 132                 }
 133
 134         }
 135
 136         switch (arg_action) {
 137
 138         case ACTION_DISSECT:
 139                 if (optind + 1 != argc) {
 140                         log_error("Expected a file path as only argument.");
 141                         return -EINVAL;
 142                 }
 143
 144                 arg_image = argv[optind];
 145                 arg_flags |= DISSECT_IMAGE_READ_ONLY;
 146                 break;
 147
 148         case ACTION_MOUNT:
 149                 if (optind + 2 != argc) {
 150                         log_error("Expected a file path and mount point path as only arguments.");
 151                         return -EINVAL;
 152                 }
 153
 154                 arg_image = argv[optind];
 155                 arg_path = argv[optind + 1];
 156                 break;
 157
 158         default:
 159                 assert_not_reached("Unknown action.");
 160         }
 161
 162         return 1;
 163 }
 164
 165 int main(int argc, char *argv[]) {
 166         _cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
 167         _cleanup_(decrypted_image_unrefp) DecryptedImage *di = NULL;
 168         _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
 169         int r;
 170
 171         log_parse_environment();
 172         log_open();
 173
 174         r = parse_argv(argc, argv);
 175         if (r <= 0)
 176                 goto finish;
 177
 178         r = loop_device_make_by_path(arg_image, (arg_flags & DISSECT_IMAGE_READ_ONLY) ? O_RDONLY : O_RDWR, &d);
 179         if (r < 0) {
 180                 log_error_errno(r, "Failed to set up loopback device: %m");
 181                 goto finish;
 182         }
 183
 184         if (!arg_root_hash) {
 185                 r = root_hash_load(arg_image, &arg_root_hash, &arg_root_hash_size);
 186                 if (r < 0) {
 187                         log_error_errno(r, "Failed to read root hash file for %s: %m", arg_image);
 188                         goto finish;
 189                 }
 190         }
 191
 192         r = dissect_image_and_warn(d->fd, arg_image, arg_root_hash, arg_root_hash_size, arg_flags, &m);
 193         if (r < 0)
 194                 goto finish;
 195
 196         switch (arg_action) {
 197
 198         case ACTION_DISSECT: {
 199                 unsigned i;
 200
 201                 for (i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
 202                         DissectedPartition *p = m->partitions + i;
 203                         int k;
 204
 205                         if (!p->found)
 206                                 continue;
 207
 208                         printf("Found %s '%s' partition",
 209                                p->rw ? "writable" : "read-only",
 210                                partition_designator_to_string(i));
 211
 212                         if (!sd_id128_is_null(p->uuid))
 213                                 printf(" (UUID " SD_ID128_FORMAT_STR ")", SD_ID128_FORMAT_VAL(p->uuid));
 214
 215                         if (p->fstype)
 216                                 printf(" of type %s", p->fstype);
 217
 218                         if (p->architecture != _ARCHITECTURE_INVALID)
 219                                 printf(" for %s", architecture_to_string(p->architecture));
 220
 221                         k = PARTITION_VERITY_OF(i);
 222                         if (k >= 0)
 223                                 printf(" %s verity", m->partitions[k].found ? "with" : "without");
 224
 225                         if (p->partno >= 0)
 226                                 printf(" on partition #%i", p->partno);
 227
 228                         if (p->node)
 229                                 printf(" (%s)", p->node);
 230
 231                         putchar('\n');
 232                 }
 233
 234                 r = dissected_image_acquire_metadata(m);
 235                 if (r < 0) {
 236                         log_error_errno(r, "Failed to acquire image metadata: %m");
 237                         goto finish;
 238                 }
 239
 240                 if (m->hostname)
 241                         printf("  Hostname: %s\n", m->hostname);
 242
 243                 if (!sd_id128_is_null(m->machine_id))
 244                         printf("Machine ID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(m->machine_id));
 245
 246                 if (!strv_isempty(m->machine_info)) {
 247                         char **p, **q;
 248
 249                         STRV_FOREACH_PAIR(p, q, m->machine_info)
 250                                 printf("%s %s=%s\n",
 251                                        p == m->machine_info ? "Mach. Info:" : "           ",
 252                                        *p, *q);
 253                 }
 254
 255                 if (!strv_isempty(m->os_release)) {
 256                         char **p, **q;
 257
 258                         STRV_FOREACH_PAIR(p, q, m->os_release)
 259                                 printf("%s %s=%s\n",
 260                                        p == m->os_release ? "OS Release:" : "           ",
 261                                        *p, *q);
 262                 }
 263
 264                 break;
 265         }
 266
 267         case ACTION_MOUNT:
 268                 r = dissected_image_decrypt_interactively(m, NULL, arg_root_hash, arg_root_hash_size, arg_flags, &di);
 269                 if (r < 0)
 270                         goto finish;
 271
 272                 r = dissected_image_mount(m, arg_path, UID_INVALID, arg_flags);
 273                 if (r < 0) {
 274                         log_error_errno(r, "Failed to mount image: %m");
 275                         goto finish;
 276                 }
 277
 278                 if (di) {
 279                         r = decrypted_image_relinquish(di);
 280                         if (r < 0) {
 281                                 log_error_errno(r, "Failed to relinquish DM devices: %m");
 282                                 goto finish;
 283                         }
 284                 }
 285
 286                 loop_device_relinquish(d);
 287                 break;
 288
 289         default:
 290                 assert_not_reached("Unknown action.");
 291         }
 292
 293 finish:
 294         free(arg_root_hash);
 295         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 296 }