1 /*
2 * Copyright (C) 2008 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 <errno.h>
18 #include <libgen.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <sys/stat.h>
23 #include <sys/statfs.h>
24 #include <sys/types.h>
25 #include <fcntl.h>
26 #include <unistd.h>
27 #include <stdbool.h>
28
29 #include "mincrypt/sha.h"
30 #include "applypatch.h"
31 #include "mtdutils/mtdutils.h"
32 #include "edify/expr.h"
33
34 static int LoadPartitionContents(const char* filename, FileContents* file);
35 static ssize_t FileSink(const unsigned char* data, ssize_t len, void* token);
36 static int GenerateTarget(FileContents* source_file,
37 const Value* source_patch_value,
38 FileContents* copy_file,
39 const Value* copy_patch_value,
40 const char* source_filename,
41 const char* target_filename,
42 const uint8_t target_sha1[SHA_DIGEST_SIZE],
43 size_t target_size,
44 const Value* bonus_data);
45
46 static int mtd_partitions_scanned = 0;
47
48 // Read a file into memory; store the file contents and associated
49 // metadata in *file.
50 //
51 // Return 0 on success.
LoadFileContents(const char * filename,FileContents * file)52 int LoadFileContents(const char* filename, FileContents* file) {
53 file->data = NULL;
54
55 // A special 'filename' beginning with "MTD:" or "EMMC:" means to
56 // load the contents of a partition.
57 if (strncmp(filename, "MTD:", 4) == 0 ||
58 strncmp(filename, "EMMC:", 5) == 0) {
59 return LoadPartitionContents(filename, file);
60 }
61
62 if (stat(filename, &file->st) != 0) {
63 printf("failed to stat \"%s\": %s\n", filename, strerror(errno));
64 return -1;
65 }
66
67 file->size = file->st.st_size;
68 file->data = malloc(file->size);
69
70 FILE* f = fopen(filename, "rb");
71 if (f == NULL) {
72 printf("failed to open \"%s\": %s\n", filename, strerror(errno));
73 free(file->data);
74 file->data = NULL;
75 return -1;
76 }
77
78 ssize_t bytes_read = fread(file->data, 1, file->size, f);
79 if (bytes_read != file->size) {
80 printf("short read of \"%s\" (%ld bytes of %ld)\n",
81 filename, (long)bytes_read, (long)file->size);
82 free(file->data);
83 file->data = NULL;
84 return -1;
85 }
86 fclose(f);
87
88 SHA_hash(file->data, file->size, file->sha1);
89 return 0;
90 }
91
92 static size_t* size_array;
93 // comparison function for qsort()ing an int array of indexes into
94 // size_array[].
compare_size_indices(const void * a,const void * b)95 static int compare_size_indices(const void* a, const void* b) {
96 int aa = *(int*)a;
97 int bb = *(int*)b;
98 if (size_array[aa] < size_array[bb]) {
99 return -1;
100 } else if (size_array[aa] > size_array[bb]) {
101 return 1;
102 } else {
103 return 0;
104 }
105 }
106
107 // Load the contents of an MTD or EMMC partition into the provided
108 // FileContents. filename should be a string of the form
109 // "MTD:<partition_name>:<size_1>:<sha1_1>:<size_2>:<sha1_2>:..." (or
110 // "EMMC:<partition_device>:..."). The smallest size_n bytes for
111 // which that prefix of the partition contents has the corresponding
112 // sha1 hash will be loaded. It is acceptable for a size value to be
113 // repeated with different sha1s. Will return 0 on success.
114 //
115 // This complexity is needed because if an OTA installation is
116 // interrupted, the partition might contain either the source or the
117 // target data, which might be of different lengths. We need to know
118 // the length in order to read from a partition (there is no
119 // "end-of-file" marker), so the caller must specify the possible
120 // lengths and the hash of the data, and we'll do the load expecting
121 // to find one of those hashes.
122 enum PartitionType { MTD, EMMC };
123
LoadPartitionContents(const char * filename,FileContents * file)124 static int LoadPartitionContents(const char* filename, FileContents* file) {
125 char* copy = strdup(filename);
126 const char* magic = strtok(copy, ":");
127
128 enum PartitionType type;
129
130 if (strcmp(magic, "MTD") == 0) {
131 type = MTD;
132 } else if (strcmp(magic, "EMMC") == 0) {
133 type = EMMC;
134 } else {
135 printf("LoadPartitionContents called with bad filename (%s)\n",
136 filename);
137 return -1;
138 }
139 const char* partition = strtok(NULL, ":");
140
141 int i;
142 int colons = 0;
143 for (i = 0; filename[i] != '\0'; ++i) {
144 if (filename[i] == ':') {
145 ++colons;
146 }
147 }
148 if (colons < 3 || colons%2 == 0) {
149 printf("LoadPartitionContents called with bad filename (%s)\n",
150 filename);
151 }
152
153 int pairs = (colons-1)/2; // # of (size,sha1) pairs in filename
154 int* index = malloc(pairs * sizeof(int));
155 size_t* size = malloc(pairs * sizeof(size_t));
156 char** sha1sum = malloc(pairs * sizeof(char*));
157
158 for (i = 0; i < pairs; ++i) {
159 const char* size_str = strtok(NULL, ":");
160 size[i] = strtol(size_str, NULL, 10);
161 if (size[i] == 0) {
162 printf("LoadPartitionContents called with bad size (%s)\n", filename);
163 return -1;
164 }
165 sha1sum[i] = strtok(NULL, ":");
166 index[i] = i;
167 }
168
169 // sort the index[] array so it indexes the pairs in order of
170 // increasing size.
171 size_array = size;
172 qsort(index, pairs, sizeof(int), compare_size_indices);
173
174 MtdReadContext* ctx = NULL;
175 FILE* dev = NULL;
176
177 switch (type) {
178 case MTD:
179 if (!mtd_partitions_scanned) {
180 mtd_scan_partitions();
181 mtd_partitions_scanned = 1;
182 }
183
184 const MtdPartition* mtd = mtd_find_partition_by_name(partition);
185 if (mtd == NULL) {
186 printf("mtd partition \"%s\" not found (loading %s)\n",
187 partition, filename);
188 return -1;
189 }
190
191 ctx = mtd_read_partition(mtd);
192 if (ctx == NULL) {
193 printf("failed to initialize read of mtd partition \"%s\"\n",
194 partition);
195 return -1;
196 }
197 break;
198
199 case EMMC:
200 dev = fopen(partition, "rb");
201 if (dev == NULL) {
202 printf("failed to open emmc partition \"%s\": %s\n",
203 partition, strerror(errno));
204 return -1;
205 }
206 }
207
208 SHA_CTX sha_ctx;
209 SHA_init(&sha_ctx);
210 uint8_t parsed_sha[SHA_DIGEST_SIZE];
211
212 // allocate enough memory to hold the largest size.
213 file->data = malloc(size[index[pairs-1]]);
214 char* p = (char*)file->data;
215 file->size = 0; // # bytes read so far
216
217 for (i = 0; i < pairs; ++i) {
218 // Read enough additional bytes to get us up to the next size
219 // (again, we're trying the possibilities in order of increasing
220 // size).
221 size_t next = size[index[i]] - file->size;
222 size_t read = 0;
223 if (next > 0) {
224 switch (type) {
225 case MTD:
226 read = mtd_read_data(ctx, p, next);
227 break;
228
229 case EMMC:
230 read = fread(p, 1, next, dev);
231 break;
232 }
233 if (next != read) {
234 printf("short read (%zu bytes of %zu) for partition \"%s\"\n",
235 read, next, partition);
236 free(file->data);
237 file->data = NULL;
238 return -1;
239 }
240 SHA_update(&sha_ctx, p, read);
241 file->size += read;
242 }
243
244 // Duplicate the SHA context and finalize the duplicate so we can
245 // check it against this pair's expected hash.
246 SHA_CTX temp_ctx;
247 memcpy(&temp_ctx, &sha_ctx, sizeof(SHA_CTX));
248 const uint8_t* sha_so_far = SHA_final(&temp_ctx);
249
250 if (ParseSha1(sha1sum[index[i]], parsed_sha) != 0) {
251 printf("failed to parse sha1 %s in %s\n",
252 sha1sum[index[i]], filename);
253 free(file->data);
254 file->data = NULL;
255 return -1;
256 }
257
258 if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) {
259 // we have a match. stop reading the partition; we'll return
260 // the data we've read so far.
261 printf("partition read matched size %zu sha %s\n",
262 size[index[i]], sha1sum[index[i]]);
263 break;
264 }
265
266 p += read;
267 }
268
269 switch (type) {
270 case MTD:
271 mtd_read_close(ctx);
272 break;
273
274 case EMMC:
275 fclose(dev);
276 break;
277 }
278
279
280 if (i == pairs) {
281 // Ran off the end of the list of (size,sha1) pairs without
282 // finding a match.
283 printf("contents of partition \"%s\" didn't match %s\n",
284 partition, filename);
285 free(file->data);
286 file->data = NULL;
287 return -1;
288 }
289
290 const uint8_t* sha_final = SHA_final(&sha_ctx);
291 for (i = 0; i < SHA_DIGEST_SIZE; ++i) {
292 file->sha1[i] = sha_final[i];
293 }
294
295 // Fake some stat() info.
296 file->st.st_mode = 0644;
297 file->st.st_uid = 0;
298 file->st.st_gid = 0;
299
300 free(copy);
301 free(index);
302 free(size);
303 free(sha1sum);
304
305 return 0;
306 }
307
308
309 // Save the contents of the given FileContents object under the given
310 // filename. Return 0 on success.
SaveFileContents(const char * filename,const FileContents * file)311 int SaveFileContents(const char* filename, const FileContents* file) {
312 int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR);
313 if (fd < 0) {
314 printf("failed to open \"%s\" for write: %s\n",
315 filename, strerror(errno));
316 return -1;
317 }
318
319 ssize_t bytes_written = FileSink(file->data, file->size, &fd);
320 if (bytes_written != file->size) {
321 printf("short write of \"%s\" (%ld bytes of %ld) (%s)\n",
322 filename, (long)bytes_written, (long)file->size,
323 strerror(errno));
324 close(fd);
325 return -1;
326 }
327 if (fsync(fd) != 0) {
328 printf("fsync of \"%s\" failed: %s\n", filename, strerror(errno));
329 return -1;
330 }
331 if (close(fd) != 0) {
332 printf("close of \"%s\" failed: %s\n", filename, strerror(errno));
333 return -1;
334 }
335
336 if (chmod(filename, file->st.st_mode) != 0) {
337 printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno));
338 return -1;
339 }
340 if (chown(filename, file->st.st_uid, file->st.st_gid) != 0) {
341 printf("chown of \"%s\" failed: %s\n", filename, strerror(errno));
342 return -1;
343 }
344
345 return 0;
346 }
347
348 // Write a memory buffer to 'target' partition, a string of the form
349 // "MTD:<partition>[:...]" or "EMMC:<partition_device>:". Return 0 on
350 // success.
WriteToPartition(unsigned char * data,size_t len,const char * target)351 int WriteToPartition(unsigned char* data, size_t len,
352 const char* target) {
353 char* copy = strdup(target);
354 const char* magic = strtok(copy, ":");
355
356 enum PartitionType type;
357 if (strcmp(magic, "MTD") == 0) {
358 type = MTD;
359 } else if (strcmp(magic, "EMMC") == 0) {
360 type = EMMC;
361 } else {
362 printf("WriteToPartition called with bad target (%s)\n", target);
363 return -1;
364 }
365 const char* partition = strtok(NULL, ":");
366
367 if (partition == NULL) {
368 printf("bad partition target name \"%s\"\n", target);
369 return -1;
370 }
371
372 switch (type) {
373 case MTD:
374 if (!mtd_partitions_scanned) {
375 mtd_scan_partitions();
376 mtd_partitions_scanned = 1;
377 }
378
379 const MtdPartition* mtd = mtd_find_partition_by_name(partition);
380 if (mtd == NULL) {
381 printf("mtd partition \"%s\" not found for writing\n",
382 partition);
383 return -1;
384 }
385
386 MtdWriteContext* ctx = mtd_write_partition(mtd);
387 if (ctx == NULL) {
388 printf("failed to init mtd partition \"%s\" for writing\n",
389 partition);
390 return -1;
391 }
392
393 size_t written = mtd_write_data(ctx, (char*)data, len);
394 if (written != len) {
395 printf("only wrote %zu of %zu bytes to MTD %s\n",
396 written, len, partition);
397 mtd_write_close(ctx);
398 return -1;
399 }
400
401 if (mtd_erase_blocks(ctx, -1) < 0) {
402 printf("error finishing mtd write of %s\n", partition);
403 mtd_write_close(ctx);
404 return -1;
405 }
406
407 if (mtd_write_close(ctx)) {
408 printf("error closing mtd write of %s\n", partition);
409 return -1;
410 }
411 break;
412
413 case EMMC:
414 {
415 size_t start = 0;
416 int success = 0;
417 int fd = open(partition, O_RDWR | O_SYNC);
418 if (fd < 0) {
419 printf("failed to open %s: %s\n", partition, strerror(errno));
420 return -1;
421 }
422 int attempt;
423
424 for (attempt = 0; attempt < 2; ++attempt) {
425 lseek(fd, start, SEEK_SET);
426 while (start < len) {
427 size_t to_write = len - start;
428 if (to_write > 1<<20) to_write = 1<<20;
429
430 ssize_t written = write(fd, data+start, to_write);
431 if (written < 0) {
432 if (errno == EINTR) {
433 written = 0;
434 } else {
435 printf("failed write writing to %s (%s)\n",
436 partition, strerror(errno));
437 return -1;
438 }
439 }
440 start += written;
441 }
442 if (fsync(fd) != 0) {
443 printf("failed to sync to %s (%s)\n",
444 partition, strerror(errno));
445 return -1;
446 }
447 if (close(fd) != 0) {
448 printf("failed to close %s (%s)\n",
449 partition, strerror(errno));
450 return -1;
451 }
452 fd = open(partition, O_RDONLY);
453 if (fd < 0) {
454 printf("failed to reopen %s for verify (%s)\n",
455 partition, strerror(errno));
456 return -1;
457 }
458
459 // drop caches so our subsequent verification read
460 // won't just be reading the cache.
461 sync();
462 int dc = open("/proc/sys/vm/drop_caches", O_WRONLY);
463 write(dc, "3\n", 2);
464 close(dc);
465 sleep(1);
466 printf(" caches dropped\n");
467
468 // verify
469 lseek(fd, 0, SEEK_SET);
470 unsigned char buffer[4096];
471 start = len;
472 size_t p;
473 for (p = 0; p < len; p += sizeof(buffer)) {
474 size_t to_read = len - p;
475 if (to_read > sizeof(buffer)) to_read = sizeof(buffer);
476
477 size_t so_far = 0;
478 while (so_far < to_read) {
479 ssize_t read_count = read(fd, buffer+so_far, to_read-so_far);
480 if (read_count < 0) {
481 if (errno == EINTR) {
482 read_count = 0;
483 } else {
484 printf("verify read error %s at %zu: %s\n",
485 partition, p, strerror(errno));
486 return -1;
487 }
488 }
489 if ((size_t)read_count < to_read) {
490 printf("short verify read %s at %zu: %zd %zu %s\n",
491 partition, p, read_count, to_read, strerror(errno));
492 }
493 so_far += read_count;
494 }
495
496 if (memcmp(buffer, data+p, to_read)) {
497 printf("verification failed starting at %zu\n", p);
498 start = p;
499 break;
500 }
501 }
502
503 if (start == len) {
504 printf("verification read succeeded (attempt %d)\n", attempt+1);
505 success = true;
506 break;
507 }
508 }
509
510 if (!success) {
511 printf("failed to verify after all attempts\n");
512 return -1;
513 }
514
515 if (close(fd) != 0) {
516 printf("error closing %s (%s)\n", partition, strerror(errno));
517 return -1;
518 }
519 sync();
520 break;
521 }
522 }
523
524 free(copy);
525 return 0;
526 }
527
528
529 // Take a string 'str' of 40 hex digits and parse it into the 20
530 // byte array 'digest'. 'str' may contain only the digest or be of
531 // the form "<digest>:<anything>". Return 0 on success, -1 on any
532 // error.
ParseSha1(const char * str,uint8_t * digest)533 int ParseSha1(const char* str, uint8_t* digest) {
534 int i;
535 const char* ps = str;
536 uint8_t* pd = digest;
537 for (i = 0; i < SHA_DIGEST_SIZE * 2; ++i, ++ps) {
538 int digit;
539 if (*ps >= '0' && *ps <= '9') {
540 digit = *ps - '0';
541 } else if (*ps >= 'a' && *ps <= 'f') {
542 digit = *ps - 'a' + 10;
543 } else if (*ps >= 'A' && *ps <= 'F') {
544 digit = *ps - 'A' + 10;
545 } else {
546 return -1;
547 }
548 if (i % 2 == 0) {
549 *pd = digit << 4;
550 } else {
551 *pd |= digit;
552 ++pd;
553 }
554 }
555 if (*ps != '\0') return -1;
556 return 0;
557 }
558
559 // Search an array of sha1 strings for one matching the given sha1.
560 // Return the index of the match on success, or -1 if no match is
561 // found.
FindMatchingPatch(uint8_t * sha1,char * const * const patch_sha1_str,int num_patches)562 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str,
563 int num_patches) {
564 int i;
565 uint8_t patch_sha1[SHA_DIGEST_SIZE];
566 for (i = 0; i < num_patches; ++i) {
567 if (ParseSha1(patch_sha1_str[i], patch_sha1) == 0 &&
568 memcmp(patch_sha1, sha1, SHA_DIGEST_SIZE) == 0) {
569 return i;
570 }
571 }
572 return -1;
573 }
574
575 // Returns 0 if the contents of the file (argv[2]) or the cached file
576 // match any of the sha1's on the command line (argv[3:]). Returns
577 // nonzero otherwise.
applypatch_check(const char * filename,int num_patches,char ** const patch_sha1_str)578 int applypatch_check(const char* filename,
579 int num_patches, char** const patch_sha1_str) {
580 FileContents file;
581 file.data = NULL;
582
583 // It's okay to specify no sha1s; the check will pass if the
584 // LoadFileContents is successful. (Useful for reading
585 // partitions, where the filename encodes the sha1s; no need to
586 // check them twice.)
587 if (LoadFileContents(filename, &file) != 0 ||
588 (num_patches > 0 &&
589 FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) {
590 printf("file \"%s\" doesn't have any of expected "
591 "sha1 sums; checking cache\n", filename);
592
593 free(file.data);
594 file.data = NULL;
595
596 // If the source file is missing or corrupted, it might be because
597 // we were killed in the middle of patching it. A copy of it
598 // should have been made in CACHE_TEMP_SOURCE. If that file
599 // exists and matches the sha1 we're looking for, the check still
600 // passes.
601
602 if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) {
603 printf("failed to load cache file\n");
604 return 1;
605 }
606
607 if (FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0) {
608 printf("cache bits don't match any sha1 for \"%s\"\n", filename);
609 free(file.data);
610 return 1;
611 }
612 }
613
614 free(file.data);
615 return 0;
616 }
617
ShowLicenses()618 int ShowLicenses() {
619 ShowBSDiffLicense();
620 return 0;
621 }
622
FileSink(const unsigned char * data,ssize_t len,void * token)623 ssize_t FileSink(const unsigned char* data, ssize_t len, void* token) {
624 int fd = *(int *)token;
625 ssize_t done = 0;
626 ssize_t wrote;
627 while (done < (ssize_t) len) {
628 wrote = write(fd, data+done, len-done);
629 if (wrote <= 0) {
630 printf("error writing %d bytes: %s\n", (int)(len-done), strerror(errno));
631 return done;
632 }
633 done += wrote;
634 }
635 return done;
636 }
637
638 typedef struct {
639 unsigned char* buffer;
640 ssize_t size;
641 ssize_t pos;
642 } MemorySinkInfo;
643
MemorySink(const unsigned char * data,ssize_t len,void * token)644 ssize_t MemorySink(const unsigned char* data, ssize_t len, void* token) {
645 MemorySinkInfo* msi = (MemorySinkInfo*)token;
646 if (msi->size - msi->pos < len) {
647 return -1;
648 }
649 memcpy(msi->buffer + msi->pos, data, len);
650 msi->pos += len;
651 return len;
652 }
653
654 // Return the amount of free space (in bytes) on the filesystem
655 // containing filename. filename must exist. Return -1 on error.
FreeSpaceForFile(const char * filename)656 size_t FreeSpaceForFile(const char* filename) {
657 struct statfs sf;
658 if (statfs(filename, &sf) != 0) {
659 printf("failed to statfs %s: %s\n", filename, strerror(errno));
660 return -1;
661 }
662 return sf.f_bsize * sf.f_bfree;
663 }
664
CacheSizeCheck(size_t bytes)665 int CacheSizeCheck(size_t bytes) {
666 if (MakeFreeSpaceOnCache(bytes) < 0) {
667 printf("unable to make %ld bytes available on /cache\n", (long)bytes);
668 return 1;
669 } else {
670 return 0;
671 }
672 }
673
print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE])674 static void print_short_sha1(const uint8_t sha1[SHA_DIGEST_SIZE]) {
675 int i;
676 const char* hex = "0123456789abcdef";
677 for (i = 0; i < 4; ++i) {
678 putchar(hex[(sha1[i]>>4) & 0xf]);
679 putchar(hex[sha1[i] & 0xf]);
680 }
681 }
682
683 // This function applies binary patches to files in a way that is safe
684 // (the original file is not touched until we have the desired
685 // replacement for it) and idempotent (it's okay to run this program
686 // multiple times).
687 //
688 // - if the sha1 hash of <target_filename> is <target_sha1_string>,
689 // does nothing and exits successfully.
690 //
691 // - otherwise, if the sha1 hash of <source_filename> is one of the
692 // entries in <patch_sha1_str>, the corresponding patch from
693 // <patch_data> (which must be a VAL_BLOB) is applied to produce a
694 // new file (the type of patch is automatically detected from the
695 // blob daat). If that new file has sha1 hash <target_sha1_str>,
696 // moves it to replace <target_filename>, and exits successfully.
697 // Note that if <source_filename> and <target_filename> are not the
698 // same, <source_filename> is NOT deleted on success.
699 // <target_filename> may be the string "-" to mean "the same as
700 // source_filename".
701 //
702 // - otherwise, or if any error is encountered, exits with non-zero
703 // status.
704 //
705 // <source_filename> may refer to a partition to read the source data.
706 // See the comments for the LoadPartition Contents() function above
707 // for the format of such a filename.
708
applypatch(const char * source_filename,const char * target_filename,const char * target_sha1_str,size_t target_size,int num_patches,char ** const patch_sha1_str,Value ** patch_data,Value * bonus_data)709 int applypatch(const char* source_filename,
710 const char* target_filename,
711 const char* target_sha1_str,
712 size_t target_size,
713 int num_patches,
714 char** const patch_sha1_str,
715 Value** patch_data,
716 Value* bonus_data) {
717 printf("patch %s: ", source_filename);
718
719 if (target_filename[0] == '-' &&
720 target_filename[1] == '\0') {
721 target_filename = source_filename;
722 }
723
724 uint8_t target_sha1[SHA_DIGEST_SIZE];
725 if (ParseSha1(target_sha1_str, target_sha1) != 0) {
726 printf("failed to parse tgt-sha1 \"%s\"\n", target_sha1_str);
727 return 1;
728 }
729
730 FileContents copy_file;
731 FileContents source_file;
732 copy_file.data = NULL;
733 source_file.data = NULL;
734 const Value* source_patch_value = NULL;
735 const Value* copy_patch_value = NULL;
736
737 // We try to load the target file into the source_file object.
738 if (LoadFileContents(target_filename, &source_file) == 0) {
739 if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) {
740 // The early-exit case: the patch was already applied, this file
741 // has the desired hash, nothing for us to do.
742 printf("already ");
743 print_short_sha1(target_sha1);
744 putchar('\n');
745 free(source_file.data);
746 return 0;
747 }
748 }
749
750 if (source_file.data == NULL ||
751 (target_filename != source_filename &&
752 strcmp(target_filename, source_filename) != 0)) {
753 // Need to load the source file: either we failed to load the
754 // target file, or we did but it's different from the source file.
755 free(source_file.data);
756 source_file.data = NULL;
757 LoadFileContents(source_filename, &source_file);
758 }
759
760 if (source_file.data != NULL) {
761 int to_use = FindMatchingPatch(source_file.sha1,
762 patch_sha1_str, num_patches);
763 if (to_use >= 0) {
764 source_patch_value = patch_data[to_use];
765 }
766 }
767
768 if (source_patch_value == NULL) {
769 free(source_file.data);
770 source_file.data = NULL;
771 printf("source file is bad; trying copy\n");
772
773 if (LoadFileContents(CACHE_TEMP_SOURCE, ©_file) < 0) {
774 // fail.
775 printf("failed to read copy file\n");
776 return 1;
777 }
778
779 int to_use = FindMatchingPatch(copy_file.sha1,
780 patch_sha1_str, num_patches);
781 if (to_use >= 0) {
782 copy_patch_value = patch_data[to_use];
783 }
784
785 if (copy_patch_value == NULL) {
786 // fail.
787 printf("copy file doesn't match source SHA-1s either\n");
788 free(copy_file.data);
789 return 1;
790 }
791 }
792
793 int result = GenerateTarget(&source_file, source_patch_value,
794 ©_file, copy_patch_value,
795 source_filename, target_filename,
796 target_sha1, target_size, bonus_data);
797 free(source_file.data);
798 free(copy_file.data);
799
800 return result;
801 }
802
GenerateTarget(FileContents * source_file,const Value * source_patch_value,FileContents * copy_file,const Value * copy_patch_value,const char * source_filename,const char * target_filename,const uint8_t target_sha1[SHA_DIGEST_SIZE],size_t target_size,const Value * bonus_data)803 static int GenerateTarget(FileContents* source_file,
804 const Value* source_patch_value,
805 FileContents* copy_file,
806 const Value* copy_patch_value,
807 const char* source_filename,
808 const char* target_filename,
809 const uint8_t target_sha1[SHA_DIGEST_SIZE],
810 size_t target_size,
811 const Value* bonus_data) {
812 int retry = 1;
813 SHA_CTX ctx;
814 int output;
815 MemorySinkInfo msi;
816 FileContents* source_to_use;
817 char* outname;
818 int made_copy = 0;
819
820 // assume that target_filename (eg "/system/app/Foo.apk") is located
821 // on the same filesystem as its top-level directory ("/system").
822 // We need something that exists for calling statfs().
823 char target_fs[strlen(target_filename)+1];
824 char* slash = strchr(target_filename+1, '/');
825 if (slash != NULL) {
826 int count = slash - target_filename;
827 strncpy(target_fs, target_filename, count);
828 target_fs[count] = '\0';
829 } else {
830 strcpy(target_fs, target_filename);
831 }
832
833 do {
834 // Is there enough room in the target filesystem to hold the patched
835 // file?
836
837 if (strncmp(target_filename, "MTD:", 4) == 0 ||
838 strncmp(target_filename, "EMMC:", 5) == 0) {
839 // If the target is a partition, we're actually going to
840 // write the output to /tmp and then copy it to the
841 // partition. statfs() always returns 0 blocks free for
842 // /tmp, so instead we'll just assume that /tmp has enough
843 // space to hold the file.
844
845 // We still write the original source to cache, in case
846 // the partition write is interrupted.
847 if (MakeFreeSpaceOnCache(source_file->size) < 0) {
848 printf("not enough free space on /cache\n");
849 return 1;
850 }
851 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) {
852 printf("failed to back up source file\n");
853 return 1;
854 }
855 made_copy = 1;
856 retry = 0;
857 } else {
858 int enough_space = 0;
859 if (retry > 0) {
860 size_t free_space = FreeSpaceForFile(target_fs);
861 enough_space =
862 (free_space > (256 << 10)) && // 256k (two-block) minimum
863 (free_space > (target_size * 3 / 2)); // 50% margin of error
864 if (!enough_space) {
865 printf("target %ld bytes; free space %ld bytes; retry %d; enough %d\n",
866 (long)target_size, (long)free_space, retry, enough_space);
867 }
868 }
869
870 if (!enough_space) {
871 retry = 0;
872 }
873
874 if (!enough_space && source_patch_value != NULL) {
875 // Using the original source, but not enough free space. First
876 // copy the source file to cache, then delete it from the original
877 // location.
878
879 if (strncmp(source_filename, "MTD:", 4) == 0 ||
880 strncmp(source_filename, "EMMC:", 5) == 0) {
881 // It's impossible to free space on the target filesystem by
882 // deleting the source if the source is a partition. If
883 // we're ever in a state where we need to do this, fail.
884 printf("not enough free space for target but source "
885 "is partition\n");
886 return 1;
887 }
888
889 if (MakeFreeSpaceOnCache(source_file->size) < 0) {
890 printf("not enough free space on /cache\n");
891 return 1;
892 }
893
894 if (SaveFileContents(CACHE_TEMP_SOURCE, source_file) < 0) {
895 printf("failed to back up source file\n");
896 return 1;
897 }
898 made_copy = 1;
899 unlink(source_filename);
900
901 size_t free_space = FreeSpaceForFile(target_fs);
902 printf("(now %ld bytes free for target) ", (long)free_space);
903 }
904 }
905
906 const Value* patch;
907 if (source_patch_value != NULL) {
908 source_to_use = source_file;
909 patch = source_patch_value;
910 } else {
911 source_to_use = copy_file;
912 patch = copy_patch_value;
913 }
914
915 if (patch->type != VAL_BLOB) {
916 printf("patch is not a blob\n");
917 return 1;
918 }
919
920 SinkFn sink = NULL;
921 void* token = NULL;
922 output = -1;
923 outname = NULL;
924 if (strncmp(target_filename, "MTD:", 4) == 0 ||
925 strncmp(target_filename, "EMMC:", 5) == 0) {
926 // We store the decoded output in memory.
927 msi.buffer = malloc(target_size);
928 if (msi.buffer == NULL) {
929 printf("failed to alloc %ld bytes for output\n",
930 (long)target_size);
931 return 1;
932 }
933 msi.pos = 0;
934 msi.size = target_size;
935 sink = MemorySink;
936 token = &msi;
937 } else {
938 // We write the decoded output to "<tgt-file>.patch".
939 outname = (char*)malloc(strlen(target_filename) + 10);
940 strcpy(outname, target_filename);
941 strcat(outname, ".patch");
942
943 output = open(outname, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC,
944 S_IRUSR | S_IWUSR);
945 if (output < 0) {
946 printf("failed to open output file %s: %s\n",
947 outname, strerror(errno));
948 return 1;
949 }
950 sink = FileSink;
951 token = &output;
952 }
953
954 char* header = patch->data;
955 ssize_t header_bytes_read = patch->size;
956
957 SHA_init(&ctx);
958
959 int result;
960
961 if (header_bytes_read >= 8 &&
962 memcmp(header, "BSDIFF40", 8) == 0) {
963 result = ApplyBSDiffPatch(source_to_use->data, source_to_use->size,
964 patch, 0, sink, token, &ctx);
965 } else if (header_bytes_read >= 8 &&
966 memcmp(header, "IMGDIFF2", 8) == 0) {
967 result = ApplyImagePatch(source_to_use->data, source_to_use->size,
968 patch, sink, token, &ctx, bonus_data);
969 } else {
970 printf("Unknown patch file format\n");
971 return 1;
972 }
973
974 if (output >= 0) {
975 if (fsync(output) != 0) {
976 printf("failed to fsync file \"%s\" (%s)\n", outname, strerror(errno));
977 result = 1;
978 }
979 if (close(output) != 0) {
980 printf("failed to close file \"%s\" (%s)\n", outname, strerror(errno));
981 result = 1;
982 }
983 }
984
985 if (result != 0) {
986 if (retry == 0) {
987 printf("applying patch failed\n");
988 return result != 0;
989 } else {
990 printf("applying patch failed; retrying\n");
991 }
992 if (outname != NULL) {
993 unlink(outname);
994 }
995 } else {
996 // succeeded; no need to retry
997 break;
998 }
999 } while (retry-- > 0);
1000
1001 const uint8_t* current_target_sha1 = SHA_final(&ctx);
1002 if (memcmp(current_target_sha1, target_sha1, SHA_DIGEST_SIZE) != 0) {
1003 printf("patch did not produce expected sha1\n");
1004 return 1;
1005 } else {
1006 printf("now ");
1007 print_short_sha1(target_sha1);
1008 putchar('\n');
1009 }
1010
1011 if (output < 0) {
1012 // Copy the temp file to the partition.
1013 if (WriteToPartition(msi.buffer, msi.pos, target_filename) != 0) {
1014 printf("write of patched data to %s failed\n", target_filename);
1015 return 1;
1016 }
1017 free(msi.buffer);
1018 } else {
1019 // Give the .patch file the same owner, group, and mode of the
1020 // original source file.
1021 if (chmod(outname, source_to_use->st.st_mode) != 0) {
1022 printf("chmod of \"%s\" failed: %s\n", outname, strerror(errno));
1023 return 1;
1024 }
1025 if (chown(outname, source_to_use->st.st_uid,
1026 source_to_use->st.st_gid) != 0) {
1027 printf("chown of \"%s\" failed: %s\n", outname, strerror(errno));
1028 return 1;
1029 }
1030
1031 // Finally, rename the .patch file to replace the target file.
1032 if (rename(outname, target_filename) != 0) {
1033 printf("rename of .patch to \"%s\" failed: %s\n",
1034 target_filename, strerror(errno));
1035 return 1;
1036 }
1037 }
1038
1039 // If this run of applypatch created the copy, and we're here, we
1040 // can delete it.
1041 if (made_copy) unlink(CACHE_TEMP_SOURCE);
1042
1043 // Success!
1044 return 0;
1045 }
1046