1 #define _GNU_SOURCE
2
3 #include <stdio.h>
4 #include <getopt.h>
5 #include <string.h>
6 #include <unistd.h>
7 #include <limits.h>
8 #include <ext2fs/ext2fs.h>
9
10 #include "perms.h"
11 #include "base_fs.h"
12 #include "block_list.h"
13 #include "basefs_allocator.h"
14 #include "create_inode.h"
15
16 #ifndef UID_GID_MAP_MAX_EXTENTS
17 /*
18 * The value is defined in linux/user_namspace.h.
19 * The value is (arbitrarily) 5 in 4.14 and earlier, or 340 in 4.15 and later.
20 * Here, the bigger value is taken. See also man user_namespace(7).
21 */
22 #define UID_GID_MAP_MAX_EXTENTS 340
23 #endif
24
25 static char *prog_name = "e2fsdroid";
26 static char *in_file;
27 static char *block_list;
28 static char *basefs_out;
29 static char *basefs_in;
30 static char *mountpoint = "";
31 static time_t fixed_time = -1;
32 static char *fs_config_file;
33 static struct selinux_opt seopt_file[8];
34 static int max_nr_opt = (int)sizeof(seopt_file) / sizeof(seopt_file[0]);
35 static char *product_out;
36 static char *src_dir;
37 static int android_configure;
38 static int android_sparse_file = 1;
39
usage(int ret)40 static void usage(int ret)
41 {
42 fprintf(stderr, "%s [-B block_list] [-D basefs_out] [-T timestamp]\n"
43 "\t[-C fs_config] [-S file_contexts] [-p product_out]\n"
44 "\t[-a mountpoint] [-d basefs_in] [-f src_dir] [-e] [-s]\n"
45 "\t[-u uid-mapping] [-g gid-mapping] image\n",
46 prog_name);
47 exit(ret);
48 }
49
absolute_path(const char * file)50 static char *absolute_path(const char *file)
51 {
52 char *ret;
53 char cwd[PATH_MAX];
54
55 if (file[0] != '/') {
56 if (getcwd(cwd, PATH_MAX) == NULL) {
57 fprintf(stderr, "Failed to getcwd\n");
58 exit(EXIT_FAILURE);
59 }
60 ret = malloc(strlen(cwd) + 1 + strlen(file) + 1);
61 if (ret)
62 sprintf(ret, "%s/%s", cwd, file);
63 } else
64 ret = strdup(file);
65 return ret;
66 }
67
parse_ugid_map_entry(char * line,struct ugid_map_entry * result)68 static int parse_ugid_map_entry(char* line, struct ugid_map_entry* result)
69 {
70 char *token, *token_saveptr;
71 size_t num_tokens;
72 unsigned int *parsed[] = {&result->child_id,
73 &result->parent_id,
74 &result->length};
75 for (token = strtok_r(line, " ", &token_saveptr), num_tokens = 0;
76 token && num_tokens < 3;
77 token = strtok_r(NULL, " ", &token_saveptr), ++num_tokens) {
78 char* endptr = NULL;
79 *parsed[num_tokens] = strtoul(token, &endptr, 10);
80 if ((*parsed[num_tokens] == ULONG_MAX && errno) || *endptr) {
81 fprintf(stderr, "Malformed u/gid mapping line\n");
82 return 0;
83 }
84 }
85 if (num_tokens < 3 || strtok_r(NULL, " ", &token_saveptr) != NULL) {
86 fprintf(stderr, "Malformed u/gid mapping line\n");
87 return 0;
88 }
89 if (result->child_id + result->length < result->child_id ||
90 result->parent_id + result->length < result->parent_id) {
91 fprintf(stderr, "u/gid mapping overflow\n");
92 return 0;
93 }
94 return 1;
95 }
96
97 /*
98 * Returns 1 if [begin1, begin1+length1) and [begin2, begin2+length2) have
99 * overlapping range. Otherwise 0.
100 */
is_overlapping(unsigned int begin1,unsigned int length1,unsigned int begin2,unsigned int length2)101 static int is_overlapping(unsigned int begin1, unsigned int length1,
102 unsigned int begin2, unsigned int length2)
103 {
104 unsigned int end1 = begin1 + length1;
105 unsigned int end2 = begin2 + length2;
106 return !(end1 <= begin2 || end2 <= begin1);
107 }
108
109 /*
110 * Verifies if the given mapping works.
111 * - Checks if the number of entries is less than or equals to
112 * UID_GID_MAP_MAX_EXTENTS.
113 * - Checks if there is no overlapped ranges.
114 * Returns 1 if valid, otherwise 0.
115 */
is_valid_ugid_map(const struct ugid_map * mapping)116 static int is_valid_ugid_map(const struct ugid_map* mapping)
117 {
118 size_t i, j;
119
120 if (mapping->size > UID_GID_MAP_MAX_EXTENTS) {
121 fprintf(stderr, "too many u/gid mapping entries\n");
122 return 0;
123 }
124
125 for (i = 0; i < mapping->size; ++i) {
126 const struct ugid_map_entry *entry1 = &mapping->entries[i];
127 for (j = i + 1; j < mapping->size; ++j) {
128 const struct ugid_map_entry *entry2 =
129 &mapping->entries[j];
130 if (is_overlapping(entry1->child_id, entry1->length,
131 entry2->child_id, entry2->length)) {
132 fprintf(stderr,
133 "Overlapping child u/gid: [%d %d %d],"
134 " [%d %d %d]\n",
135 entry1->child_id, entry1->parent_id,
136 entry1->length, entry2->child_id,
137 entry2->parent_id, entry2->length);
138 return 0;
139 }
140 if (is_overlapping(entry1->parent_id, entry1->length,
141 entry2->parent_id, entry2->length)) {
142 fprintf(stderr,
143 "Overlapping parent u/gid: [%d %d %d],"
144 " [%d %d %d]\n",
145 entry1->child_id, entry1->parent_id,
146 entry1->length, entry2->child_id,
147 entry2->parent_id, entry2->length);
148 return 0;
149 }
150 }
151 }
152 return 1;
153 }
154
155 /*
156 * Parses the UID/GID mapping argument. The argument could be a multi-line
157 * string (separated by '\n', no trailing '\n' is allowed). Each line must
158 * contain exact three integer tokens; the first token is |child_id|,
159 * the second is |parent_id|, and the last is |length| of the mapping range.
160 * See also user_namespace(7) man page.
161 * On success, the parsed entries are stored in |result|, and it returns 1.
162 * Otherwise, returns 0.
163 */
parse_ugid_map(char * arg,struct ugid_map * result)164 static int parse_ugid_map(char* arg, struct ugid_map* result)
165 {
166 int i;
167 char *line, *line_saveptr;
168 size_t current_index;
169
170 /* Count the number of lines. */
171 result->size = 1;
172 for (i = 0; arg[i]; ++i) {
173 if (arg[i] == '\n')
174 ++result->size;
175 }
176
177 /* Allocate memory for entries. */
178 result->entries = malloc(sizeof(struct ugid_map_entry) * result->size);
179 if (!result->entries) {
180 result->size = 0;
181 return 0;
182 }
183
184 /* Parse each line */
185 for (line = strtok_r(arg, "\n", &line_saveptr), current_index = 0;
186 line;
187 line = strtok_r(NULL, "\n", &line_saveptr), ++current_index) {
188 if (!parse_ugid_map_entry(
189 line, &result->entries[current_index])) {
190 return 0;
191 }
192 }
193
194 return is_valid_ugid_map(result);
195 }
196
main(int argc,char * argv[])197 int main(int argc, char *argv[])
198 {
199 int c;
200 char *p;
201 int flags = EXT2_FLAG_RW;
202 errcode_t retval;
203 io_manager io_mgr;
204 ext2_filsys fs = NULL;
205 struct fs_ops_callbacks fs_callbacks = { NULL, NULL };
206 char *token;
207 int nr_opt = 0;
208 ext2_ino_t inodes_count;
209 ext2_ino_t free_inodes_count;
210 blk64_t blocks_count;
211 blk64_t free_blocks_count;
212 struct ugid_map uid_map = { 0, NULL }, gid_map = { 0, NULL };
213
214 add_error_table(&et_ext2_error_table);
215
216 while ((c = getopt (argc, argv, "T:C:S:p:a:D:d:B:f:esu:g:")) != EOF) {
217 switch (c) {
218 case 'T':
219 fixed_time = strtoul(optarg, &p, 0);
220 android_configure = 1;
221 break;
222 case 'C':
223 fs_config_file = absolute_path(optarg);
224 android_configure = 1;
225 break;
226 case 'S':
227 token = strtok(optarg, ",");
228 while (token) {
229 if (nr_opt == max_nr_opt) {
230 fprintf(stderr, "Expected at most %d selinux opts\n",
231 max_nr_opt);
232 exit(EXIT_FAILURE);
233 }
234 seopt_file[nr_opt].type = SELABEL_OPT_PATH;
235 seopt_file[nr_opt].value = absolute_path(token);
236 nr_opt++;
237 token = strtok(NULL, ",");
238 }
239 android_configure = 1;
240 break;
241 case 'p':
242 product_out = absolute_path(optarg);
243 android_configure = 1;
244 break;
245 case 'a':
246 mountpoint = strdup(optarg);
247 break;
248 case 'D':
249 basefs_out = absolute_path(optarg);
250 break;
251 case 'd':
252 basefs_in = absolute_path(optarg);
253 break;
254 case 'B':
255 block_list = absolute_path(optarg);
256 break;
257 case 'f':
258 src_dir = absolute_path(optarg);
259 break;
260 case 'e':
261 android_sparse_file = 0;
262 break;
263 case 's':
264 flags |= EXT2_FLAG_SHARE_DUP;
265 break;
266 case 'u':
267 if (!parse_ugid_map(optarg, &uid_map))
268 exit(EXIT_FAILURE);
269 android_configure = 1;
270 break;
271 case 'g':
272 if (!parse_ugid_map(optarg, &gid_map))
273 exit(EXIT_FAILURE);
274 android_configure = 1;
275 break;
276 default:
277 usage(EXIT_FAILURE);
278 }
279 }
280 if (optind >= argc) {
281 fprintf(stderr, "Expected filename after options\n");
282 exit(EXIT_FAILURE);
283 }
284
285 if (android_sparse_file) {
286 io_mgr = sparse_io_manager;
287 if (asprintf(&in_file, "(%s)", argv[optind]) == -1) {
288 fprintf(stderr, "Failed to allocate file name\n");
289 exit(EXIT_FAILURE);
290 }
291 } else {
292 io_mgr = unix_io_manager;
293 in_file = strdup(argv[optind]);
294 }
295 retval = ext2fs_open(in_file, flags, 0, 0, io_mgr, &fs);
296 if (retval) {
297 com_err(prog_name, retval, "while opening file %s\n", in_file);
298 return retval;
299 }
300
301 if (src_dir) {
302 ext2fs_read_bitmaps(fs);
303 if (basefs_in) {
304 retval = base_fs_alloc_load(fs, basefs_in, mountpoint);
305 if (retval) {
306 com_err(prog_name, retval, "%s",
307 "while reading base_fs file");
308 exit(1);
309 }
310 fs_callbacks.create_new_inode =
311 base_fs_alloc_set_target;
312 fs_callbacks.end_create_new_inode =
313 base_fs_alloc_unset_target;
314 }
315 retval = populate_fs2(fs, EXT2_ROOT_INO, src_dir,
316 EXT2_ROOT_INO, &fs_callbacks);
317 if (retval) {
318 com_err(prog_name, retval, "%s",
319 "while populating file system");
320 exit(1);
321 }
322 if (basefs_in)
323 base_fs_alloc_cleanup(fs);
324 }
325
326 if (android_configure) {
327 retval = android_configure_fs(
328 fs, src_dir, product_out, mountpoint, seopt_file,
329 nr_opt, fs_config_file, fixed_time, &uid_map, &gid_map);
330 if (retval) {
331 com_err(prog_name, retval, "%s",
332 "while configuring the file system");
333 exit(1);
334 }
335 }
336
337 if (block_list) {
338 retval = fsmap_iter_filsys(fs, &block_list_format, block_list,
339 mountpoint);
340 if (retval) {
341 com_err(prog_name, retval, "%s",
342 "while creating the block_list");
343 exit(1);
344 }
345 }
346
347 if (basefs_out) {
348 retval = fsmap_iter_filsys(fs, &base_fs_format,
349 basefs_out, mountpoint);
350 if (retval) {
351 com_err(prog_name, retval, "%s",
352 "while creating the basefs file");
353 exit(1);
354 }
355 }
356
357 inodes_count = fs->super->s_inodes_count;
358 free_inodes_count = fs->super->s_free_inodes_count;
359 blocks_count = ext2fs_blocks_count(fs->super);
360 free_blocks_count = ext2fs_free_blocks_count(fs->super);
361
362 retval = ext2fs_close_free(&fs);
363 if (retval) {
364 com_err(prog_name, retval, "%s",
365 "while writing superblocks");
366 exit(1);
367 }
368
369 printf("Created filesystem with %u/%u inodes and %llu/%llu blocks\n",
370 inodes_count - free_inodes_count, inodes_count,
371 blocks_count - free_blocks_count, blocks_count);
372
373 remove_error_table(&et_ext2_error_table);
374 return 0;
375 }
376