make_ext4fs.c revision 2e5c52322d54d0f98d36b499fcaa31a0e84ca87c 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "make_ext4fs.h"
18#include "output_file.h"
19#include "ext4_utils.h"
20#include "allocate.h"
21#include "contents.h"
22#include "uuid.h"
23#include "backed_block.h"
24
25#include <assert.h>
26#include <dirent.h>
27#include <fcntl.h>
28#include <libgen.h>
29#include <stdio.h>
30#include <stdlib.h>
31#include <string.h>
32#include <unistd.h>
33#include <sys/stat.h>
34#include <sys/types.h>
35
36#ifdef USE_MINGW
37
38#include <winsock2.h>
39
40/* These match the Linux definitions of these flags.
41   L_xx is defined to avoid conflicting with the win32 versions.
42*/
43#define L_S_IRUSR 00400
44#define L_S_IWUSR 00200
45#define L_S_IXUSR 00100
46#define S_IRWXU (L_S_IRUSR | L_S_IWUSR | L_S_IXUSR)
47#define S_IRGRP 00040
48#define S_IWGRP 00020
49#define S_IXGRP 00010
50#define S_IRWXG (S_IRGRP | S_IWGRP | S_IXGRP)
51#define S_IROTH 00004
52#define S_IWOTH 00002
53#define S_IXOTH 00001
54#define S_IRWXO (S_IROTH | S_IWOTH | S_IXOTH)
55#define S_ISUID 0004000
56#define S_ISGID 0002000
57#define S_ISVTX 0001000
58
59#else
60
61#define O_BINARY 0
62
63#endif
64
65/* TODO: Not implemented:
66   Allocating blocks in the same block group as the file inode
67   Hash or binary tree directories
68   Special files: sockets, devices, fifos
69 */
70
71static int filter_dot(const struct dirent *d)
72{
73	return (strcmp(d->d_name, "..") && strcmp(d->d_name, "."));
74}
75
76static u32 build_default_directory_structure()
77{
78	u32 inode;
79	u32 root_inode;
80	struct dentry dentries = {
81			.filename = "lost+found",
82			.file_type = EXT4_FT_DIR,
83			.mode = S_IRWXU,
84			.uid = 0,
85			.gid = 0,
86			.mtime = 0,
87	};
88	root_inode = make_directory(0, 1, &dentries, 1);
89	inode = make_directory(root_inode, 0, NULL, 0);
90	*dentries.inode = inode;
91	inode_set_permissions(inode, dentries.mode,
92		dentries.uid, dentries.gid, dentries.mtime);
93
94	return root_inode;
95}
96
97#ifndef USE_MINGW
98/* Read a local directory and create the same tree in the generated filesystem.
99   Calls itself recursively with each directory in the given directory */
100static u32 build_directory_structure(const char *full_path, const char *dir_path,
101		u32 dir_inode, fs_config_func_t fs_config_func,
102		struct selabel_handle *sehnd)
103{
104	int entries = 0;
105	struct dentry *dentries;
106	struct dirent **namelist;
107	struct stat stat;
108	int ret;
109	int i;
110	u32 inode;
111	u32 entry_inode;
112	u32 dirs = 0;
113
114	entries = scandir(full_path, &namelist, filter_dot, (void*)alphasort);
115	if (entries < 0) {
116		error_errno("scandir");
117		return EXT4_ALLOCATE_FAILED;
118	}
119
120	dentries = calloc(entries, sizeof(struct dentry));
121	if (dentries == NULL)
122		critical_error_errno("malloc");
123
124	for (i = 0; i < entries; i++) {
125		dentries[i].filename = strdup(namelist[i]->d_name);
126		if (dentries[i].filename == NULL)
127			critical_error_errno("strdup");
128
129		asprintf(&dentries[i].path, "%s/%s", dir_path, namelist[i]->d_name);
130		asprintf(&dentries[i].full_path, "%s/%s", full_path, namelist[i]->d_name);
131
132		free(namelist[i]);
133
134		ret = lstat(dentries[i].full_path, &stat);
135		if (ret < 0) {
136			error_errno("lstat");
137			i--;
138			entries--;
139			continue;
140		}
141
142		dentries[i].size = stat.st_size;
143		dentries[i].mode = stat.st_mode & (S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO);
144		dentries[i].mtime = stat.st_mtime;
145		if (fs_config_func != NULL) {
146#ifdef ANDROID
147			unsigned int mode = 0;
148			unsigned int uid = 0;
149			unsigned int gid = 0;
150			int dir = S_ISDIR(stat.st_mode);
151			fs_config_func(dentries[i].path, dir, &uid, &gid, &mode);
152			dentries[i].mode = mode;
153			dentries[i].uid = uid;
154			dentries[i].gid = gid;
155#else
156			error("can't set android permissions - built without android support");
157#endif
158		}
159#ifdef HAVE_SELINUX
160		if (sehnd) {
161			char *sepath = NULL;
162			asprintf(&sepath, "/%s", dentries[i].path);
163			if (selabel_lookup(sehnd, &dentries[i].secon, sepath, stat.st_mode) < 0) {
164				error("cannot lookup security context for %s", sepath);
165			}
166			if (dentries[i].secon)
167				printf("Labeling %s as %s\n", sepath, dentries[i].secon);
168			free(sepath);
169		}
170#endif
171
172		if (S_ISREG(stat.st_mode)) {
173			dentries[i].file_type = EXT4_FT_REG_FILE;
174		} else if (S_ISDIR(stat.st_mode)) {
175			dentries[i].file_type = EXT4_FT_DIR;
176			dirs++;
177		} else if (S_ISCHR(stat.st_mode)) {
178			dentries[i].file_type = EXT4_FT_CHRDEV;
179		} else if (S_ISBLK(stat.st_mode)) {
180			dentries[i].file_type = EXT4_FT_BLKDEV;
181		} else if (S_ISFIFO(stat.st_mode)) {
182			dentries[i].file_type = EXT4_FT_FIFO;
183		} else if (S_ISSOCK(stat.st_mode)) {
184			dentries[i].file_type = EXT4_FT_SOCK;
185		} else if (S_ISLNK(stat.st_mode)) {
186			dentries[i].file_type = EXT4_FT_SYMLINK;
187			dentries[i].link = calloc(info.block_size, 1);
188			readlink(dentries[i].full_path, dentries[i].link, info.block_size - 1);
189		} else {
190			error("unknown file type on %s", dentries[i].path);
191			i--;
192			entries--;
193		}
194	}
195	free(namelist);
196
197	inode = make_directory(dir_inode, entries, dentries, dirs);
198
199	for (i = 0; i < entries; i++) {
200		if (dentries[i].file_type == EXT4_FT_REG_FILE) {
201			entry_inode = make_file(dentries[i].full_path, dentries[i].size);
202		} else if (dentries[i].file_type == EXT4_FT_DIR) {
203			entry_inode = build_directory_structure(dentries[i].full_path,
204					dentries[i].path, inode, fs_config_func, sehnd);
205		} else if (dentries[i].file_type == EXT4_FT_SYMLINK) {
206			entry_inode = make_link(dentries[i].full_path, dentries[i].link);
207		} else {
208			error("unknown file type on %s", dentries[i].path);
209			entry_inode = 0;
210		}
211		*dentries[i].inode = entry_inode;
212
213		ret = inode_set_permissions(entry_inode, dentries[i].mode,
214			dentries[i].uid, dentries[i].gid,
215			dentries[i].mtime);
216		if (ret)
217			error("failed to set permissions on %s\n", dentries[i].path);
218		ret = inode_set_selinux(entry_inode, dentries[i].secon);
219		if (ret)
220			error("failed to set SELinux context on %s\n", dentries[i].path);
221
222		free(dentries[i].path);
223		free(dentries[i].full_path);
224		free(dentries[i].link);
225		free((void *)dentries[i].filename);
226		free(dentries[i].secon);
227	}
228
229	free(dentries);
230	return inode;
231}
232#endif
233
234static u32 compute_block_size()
235{
236	return 4096;
237}
238
239static u32 compute_journal_blocks()
240{
241	u32 journal_blocks = DIV_ROUND_UP(info.len, info.block_size) / 64;
242	if (journal_blocks < 1024)
243		journal_blocks = 1024;
244	if (journal_blocks > 32768)
245		journal_blocks = 32768;
246	return journal_blocks;
247}
248
249static u32 compute_blocks_per_group()
250{
251	return info.block_size * 8;
252}
253
254static u32 compute_inodes()
255{
256	return DIV_ROUND_UP(info.len, info.block_size) / 4;
257}
258
259static u32 compute_inodes_per_group()
260{
261	u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
262	u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
263	u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
264	inodes = ALIGN(inodes, (info.block_size / info.inode_size));
265
266	/* After properly rounding up the number of inodes/group,
267	 * make sure to update the total inodes field in the info struct.
268	 */
269	info.inodes = inodes * block_groups;
270
271	return inodes;
272}
273
274static u32 compute_bg_desc_reserve_blocks()
275{
276	u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
277	u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
278	u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
279			info.block_size);
280
281	u32 bg_desc_reserve_blocks =
282			DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
283					info.block_size) - bg_desc_blocks;
284
285	if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
286		bg_desc_reserve_blocks = info.block_size / sizeof(u32);
287
288	return bg_desc_reserve_blocks;
289}
290
291void reset_ext4fs_info() {
292    // Reset all the global data structures used by make_ext4fs so it
293    // can be called again.
294    memset(&info, 0, sizeof(info));
295    memset(&aux_info, 0, sizeof(aux_info));
296    free_data_blocks();
297}
298
299int make_ext4fs(const char *filename, s64 len,
300                const char *mountpoint, struct selabel_handle *sehnd)
301{
302	int fd;
303	int status;
304
305	reset_ext4fs_info();
306	info.len = len;
307
308	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
309	if (fd < 0) {
310		error_errno("open");
311		return EXIT_FAILURE;
312	}
313
314	status = make_ext4fs_internal(fd, NULL, mountpoint, NULL, 0, 0, 0, 1, 0, sehnd);
315	close(fd);
316
317	return status;
318}
319
320int make_ext4fs_internal(int fd, const char *directory,
321                         char *mountpoint, fs_config_func_t fs_config_func, int gzip, int sparse,
322                         int crc, int wipe, int init_itabs, struct selabel_handle *sehnd)
323{
324	u32 root_inode_num;
325	u16 root_mode;
326
327	if (setjmp(setjmp_env))
328		return EXIT_FAILURE; /* Handle a call to longjmp() */
329
330	if (info.len <= 0)
331		info.len = get_file_size(fd);
332
333	if (info.len <= 0) {
334		fprintf(stderr, "Need size of filesystem\n");
335		return EXIT_FAILURE;
336	}
337
338	if (info.block_size <= 0)
339		info.block_size = compute_block_size();
340
341	/* Round down the filesystem length to be a multiple of the block size */
342	info.len &= ~((u64)info.block_size - 1);
343
344	if (info.journal_blocks == 0)
345		info.journal_blocks = compute_journal_blocks();
346
347	if (info.no_journal == 0)
348		info.feat_compat = EXT4_FEATURE_COMPAT_HAS_JOURNAL;
349	else
350		info.journal_blocks = 0;
351
352	if (info.blocks_per_group <= 0)
353		info.blocks_per_group = compute_blocks_per_group();
354
355	if (info.inodes <= 0)
356		info.inodes = compute_inodes();
357
358	if (info.inode_size <= 0)
359		info.inode_size = 256;
360
361	if (info.label == NULL)
362		info.label = "";
363
364	info.inodes_per_group = compute_inodes_per_group();
365
366	info.feat_compat |=
367			EXT4_FEATURE_COMPAT_RESIZE_INODE;
368
369	info.feat_ro_compat |=
370			EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER |
371			EXT4_FEATURE_RO_COMPAT_LARGE_FILE;
372
373	info.feat_incompat |=
374			EXT4_FEATURE_INCOMPAT_EXTENTS |
375			EXT4_FEATURE_INCOMPAT_FILETYPE;
376
377
378	info.bg_desc_reserve_blocks = compute_bg_desc_reserve_blocks();
379
380	printf("Creating filesystem with parameters:\n");
381	printf("    Size: %llu\n", info.len);
382	printf("    Block size: %d\n", info.block_size);
383	printf("    Blocks per group: %d\n", info.blocks_per_group);
384	printf("    Inodes per group: %d\n", info.inodes_per_group);
385	printf("    Inode size: %d\n", info.inode_size);
386	printf("    Journal blocks: %d\n", info.journal_blocks);
387	printf("    Label: %s\n", info.label);
388
389	ext4_create_fs_aux_info();
390
391	printf("    Blocks: %llu\n", aux_info.len_blocks);
392	printf("    Block groups: %d\n", aux_info.groups);
393	printf("    Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
394
395	block_allocator_init();
396
397	ext4_fill_in_sb();
398
399	if (reserve_inodes(0, 10) == EXT4_ALLOCATE_FAILED)
400		error("failed to reserve first 10 inodes");
401
402	if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
403		ext4_create_journal_inode();
404
405	if (info.feat_compat & EXT4_FEATURE_COMPAT_RESIZE_INODE)
406		ext4_create_resize_inode();
407
408#ifdef USE_MINGW
409	// Windows needs only 'create an empty fs image' functionality
410	assert(!directory);
411	root_inode_num = build_default_directory_structure();
412#else
413	if (directory)
414		root_inode_num = build_directory_structure(directory, mountpoint, 0,
415                        fs_config_func, sehnd);
416	else
417		root_inode_num = build_default_directory_structure();
418#endif
419
420	root_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
421	inode_set_permissions(root_inode_num, root_mode, 0, 0, 0);
422
423#ifdef HAVE_SELINUX
424	if (sehnd) {
425		char *sepath = NULL;
426		char *secontext = NULL;
427
428		if (mountpoint[0] == '/')
429			sepath = strdup(mountpoint);
430		else
431			asprintf(&sepath, "/%s", mountpoint);
432		if (!sepath)
433			critical_error_errno("malloc");
434		if (selabel_lookup(sehnd, &secontext, sepath, S_IFDIR) < 0) {
435			error("cannot lookup security context for %s", sepath);
436		}
437		if (secontext) {
438			printf("Labeling %s as %s\n", sepath, secontext);
439			inode_set_selinux(root_inode_num, secontext);
440		}
441		free(sepath);
442		freecon(secontext);
443	}
444#endif
445
446	ext4_update_free();
447
448	if (init_itabs)
449		init_unused_inode_tables();
450
451	ext4_queue_sb();
452
453	printf("Created filesystem with %d/%d inodes and %d/%d blocks\n",
454			aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
455			aux_info.sb->s_inodes_count,
456			aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
457			aux_info.sb->s_blocks_count_lo);
458
459	write_ext4_image(fd, gzip, sparse, crc, wipe);
460
461	return 0;
462}
463