git

1
/*
2
 * Copyright (c) 2005, 2006 Rene Scharfe
3
 */
4

5
#define USE_THE_REPOSITORY_VARIABLE
6

7
#include "git-compat-util.h"
8
#include "config.h"
9
#include "gettext.h"
10
#include "git-zlib.h"
11
#include "hex.h"
12
#include "tar.h"
13
#include "archive.h"
14
#include "object-store-ll.h"
15
#include "strbuf.h"
16
#include "streaming.h"
17
#include "run-command.h"
18
#include "write-or-die.h"
19

20
#define RECORDSIZE	(512)
21
#define BLOCKSIZE	(RECORDSIZE * 20)
22

23
static char block[BLOCKSIZE];
24
static unsigned long offset;
25

26
static int tar_umask = 002;
27

28
static int write_tar_filter_archive(const struct archiver *ar,
29
				    struct archiver_args *args);
30

31
/*
32
 * This is the max value that a ustar size header can specify, as it is fixed
33
 * at 11 octal digits. POSIX specifies that we switch to extended headers at
34
 * this size.
35
 *
36
 * Likewise for the mtime (which happens to use a buffer of the same size).
37
 */
38
#if ULONG_MAX == 0xFFFFFFFF
39
#define USTAR_MAX_SIZE ULONG_MAX
40
#else
41
#define USTAR_MAX_SIZE 077777777777UL
42
#endif
43
#if TIME_MAX == 0xFFFFFFFF
44
#define USTAR_MAX_MTIME TIME_MAX
45
#else
46
#define USTAR_MAX_MTIME 077777777777ULL
47
#endif
48

49
static void tar_write_block(const void *buf)
50
{
51
	write_or_die(1, buf, BLOCKSIZE);
52
}
53

54
static void (*write_block)(const void *) = tar_write_block;
55

56
/* writes out the whole block, but only if it is full */
57
static void write_if_needed(void)
58
{
59
	if (offset == BLOCKSIZE) {
60
		write_block(block);
61
		offset = 0;
62
	}
63
}
64

65
/*
66
 * queues up writes, so that all our write(2) calls write exactly one
67
 * full block; pads writes to RECORDSIZE
68
 */
69
static void do_write_blocked(const void *data, unsigned long size)
70
{
71
	const char *buf = data;
72

73
	if (offset) {
74
		unsigned long chunk = BLOCKSIZE - offset;
75
		if (size < chunk)
76
			chunk = size;
77
		memcpy(block + offset, buf, chunk);
78
		size -= chunk;
79
		offset += chunk;
80
		buf += chunk;
81
		write_if_needed();
82
	}
83
	while (size >= BLOCKSIZE) {
84
		write_block(buf);
85
		size -= BLOCKSIZE;
86
		buf += BLOCKSIZE;
87
	}
88
	if (size) {
89
		memcpy(block + offset, buf, size);
90
		offset += size;
91
	}
92
}
93

94
static void finish_record(void)
95
{
96
	unsigned long tail;
97
	tail = offset % RECORDSIZE;
98
	if (tail)  {
99
		memset(block + offset, 0, RECORDSIZE - tail);
100
		offset += RECORDSIZE - tail;
101
	}
102
	write_if_needed();
103
}
104

105
static void write_blocked(const void *data, unsigned long size)
106
{
107
	do_write_blocked(data, size);
108
	finish_record();
109
}
110

111
/*
112
 * The end of tar archives is marked by 2*512 nul bytes and after that
113
 * follows the rest of the block (if any).
114
 */
115
static void write_trailer(void)
116
{
117
	int tail = BLOCKSIZE - offset;
118
	memset(block + offset, 0, tail);
119
	write_block(block);
120
	if (tail < 2 * RECORDSIZE) {
121
		memset(block, 0, offset);
122
		write_block(block);
123
	}
124
}
125

126
/*
127
 * queues up writes, so that all our write(2) calls write exactly one
128
 * full block; pads writes to RECORDSIZE
129
 */
130
static int stream_blocked(struct repository *r, const struct object_id *oid)
131
{
132
	struct git_istream *st;
133
	enum object_type type;
134
	unsigned long sz;
135
	char buf[BLOCKSIZE];
136
	ssize_t readlen;
137

138
	st = open_istream(r, oid, &type, &sz, NULL);
139
	if (!st)
140
		return error(_("cannot stream blob %s"), oid_to_hex(oid));
141
	for (;;) {
142
		readlen = read_istream(st, buf, sizeof(buf));
143
		if (readlen <= 0)
144
			break;
145
		do_write_blocked(buf, readlen);
146
	}
147
	close_istream(st);
148
	if (!readlen)
149
		finish_record();
150
	return readlen;
151
}
152

153
/*
154
 * pax extended header records have the format "%u %s=%s\n".  %u contains
155
 * the size of the whole string (including the %u), the first %s is the
156
 * keyword, the second one is the value.  This function constructs such a
157
 * string and appends it to a struct strbuf.
158
 */
159
static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
160
				     const char *value, size_t valuelen)
161
{
162
	size_t orig_len = sb->len;
163
	size_t len, tmp;
164

165
	/* "%u %s=%s\n" */
166
	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
167
	for (tmp = 1; len / 10 >= tmp; tmp *= 10)
168
		len++;
169

170
	strbuf_grow(sb, len);
171
	strbuf_addf(sb, "%"PRIuMAX" %s=", (uintmax_t)len, keyword);
172
	strbuf_add(sb, value, valuelen);
173
	strbuf_addch(sb, '\n');
174

175
	if (len != sb->len - orig_len)
176
		BUG("pax extended header length miscalculated as %"PRIuMAX
177
		    ", should be %"PRIuMAX,
178
		    (uintmax_t)len, (uintmax_t)(sb->len - orig_len));
179
}
180

181
/*
182
 * Like strbuf_append_ext_header, but for numeric values.
183
 */
184
static void strbuf_append_ext_header_uint(struct strbuf *sb,
185
					  const char *keyword,
186
					  uintmax_t value)
187
{
188
	char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
189
	int len;
190

191
	len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
192
	strbuf_append_ext_header(sb, keyword, buf, len);
193
}
194

195
static unsigned int ustar_header_chksum(const struct ustar_header *header)
196
{
197
	const unsigned char *p = (const unsigned char *)header;
198
	unsigned int chksum = 0;
199
	while (p < (const unsigned char *)header->chksum)
200
		chksum += *p++;
201
	chksum += sizeof(header->chksum) * ' ';
202
	p += sizeof(header->chksum);
203
	while (p < (const unsigned char *)header + sizeof(struct ustar_header))
204
		chksum += *p++;
205
	return chksum;
206
}
207

208
static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
209
{
210
	size_t i = pathlen;
211
	if (i > 1 && path[i - 1] == '/')
212
		i--;
213
	if (i > maxlen)
214
		i = maxlen;
215
	do {
216
		i--;
217
	} while (i > 0 && path[i] != '/');
218
	return i;
219
}
220

221
static void prepare_header(struct archiver_args *args,
222
			   struct ustar_header *header,
223
			   unsigned int mode, unsigned long size)
224
{
225
	xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
226
	xsnprintf(header->size, sizeof(header->size), "%011"PRIoMAX , S_ISREG(mode) ? (uintmax_t)size : (uintmax_t)0);
227
	xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
228

229
	xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
230
	xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
231
	strlcpy(header->uname, "root", sizeof(header->uname));
232
	strlcpy(header->gname, "root", sizeof(header->gname));
233
	xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
234
	xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);
235

236
	memcpy(header->magic, "ustar", 6);
237
	memcpy(header->version, "00", 2);
238

239
	xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
240
}
241

242
static void write_extended_header(struct archiver_args *args,
243
				  const struct object_id *oid,
244
				  const void *buffer, unsigned long size)
245
{
246
	struct ustar_header header;
247
	unsigned int mode;
248
	memset(&header, 0, sizeof(header));
249
	*header.typeflag = TYPEFLAG_EXT_HEADER;
250
	mode = 0100666;
251
	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid));
252
	prepare_header(args, &header, mode, size);
253
	write_blocked(&header, sizeof(header));
254
	write_blocked(buffer, size);
255
}
256

257
static int write_tar_entry(struct archiver_args *args,
258
			   const struct object_id *oid,
259
			   const char *path, size_t pathlen,
260
			   unsigned int mode,
261
			   void *buffer, unsigned long size)
262
{
263
	struct ustar_header header;
264
	struct strbuf ext_header = STRBUF_INIT;
265
	unsigned long size_in_header;
266
	int err = 0;
267

268
	memset(&header, 0, sizeof(header));
269

270
	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
271
		*header.typeflag = TYPEFLAG_DIR;
272
		mode = (mode | 0777) & ~tar_umask;
273
	} else if (S_ISLNK(mode)) {
274
		*header.typeflag = TYPEFLAG_LNK;
275
		mode |= 0777;
276
	} else if (S_ISREG(mode)) {
277
		*header.typeflag = TYPEFLAG_REG;
278
		mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
279
	} else {
280
		return error(_("unsupported file mode: 0%o (SHA1: %s)"),
281
			     mode, oid_to_hex(oid));
282
	}
283
	if (pathlen > sizeof(header.name)) {
284
		size_t plen = get_path_prefix(path, pathlen,
285
					      sizeof(header.prefix));
286
		size_t rest = pathlen - plen - 1;
287
		if (plen > 0 && rest <= sizeof(header.name)) {
288
			memcpy(header.prefix, path, plen);
289
			memcpy(header.name, path + plen + 1, rest);
290
		} else {
291
			xsnprintf(header.name, sizeof(header.name), "%s.data",
292
				  oid_to_hex(oid));
293
			strbuf_append_ext_header(&ext_header, "path",
294
						 path, pathlen);
295
		}
296
	} else
297
		memcpy(header.name, path, pathlen);
298

299
	if (S_ISLNK(mode)) {
300
		if (size > sizeof(header.linkname)) {
301
			xsnprintf(header.linkname, sizeof(header.linkname),
302
				  "see %s.paxheader", oid_to_hex(oid));
303
			strbuf_append_ext_header(&ext_header, "linkpath",
304
			                         buffer, size);
305
		} else
306
			memcpy(header.linkname, buffer, size);
307
	}
308

309
	size_in_header = size;
310
	if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
311
		size_in_header = 0;
312
		strbuf_append_ext_header_uint(&ext_header, "size", size);
313
	}
314

315
	prepare_header(args, &header, mode, size_in_header);
316

317
	if (ext_header.len > 0) {
318
		write_extended_header(args, oid, ext_header.buf,
319
				      ext_header.len);
320
	}
321
	strbuf_release(&ext_header);
322
	write_blocked(&header, sizeof(header));
323
	if (S_ISREG(mode) && size > 0) {
324
		if (buffer)
325
			write_blocked(buffer, size);
326
		else
327
			err = stream_blocked(args->repo, oid);
328
	}
329
	return err;
330
}
331

332
static void write_global_extended_header(struct archiver_args *args)
333
{
334
	const struct object_id *oid = args->commit_oid;
335
	struct strbuf ext_header = STRBUF_INIT;
336
	struct ustar_header header;
337
	unsigned int mode;
338

339
	if (oid)
340
		strbuf_append_ext_header(&ext_header, "comment",
341
					 oid_to_hex(oid),
342
					 the_hash_algo->hexsz);
343
	if (args->time > USTAR_MAX_MTIME) {
344
		strbuf_append_ext_header_uint(&ext_header, "mtime",
345
					      args->time);
346
		args->time = USTAR_MAX_MTIME;
347
	}
348

349
	if (!ext_header.len)
350
		return;
351

352
	memset(&header, 0, sizeof(header));
353
	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
354
	mode = 0100666;
355
	xsnprintf(header.name, sizeof(header.name), "pax_global_header");
356
	prepare_header(args, &header, mode, ext_header.len);
357
	write_blocked(&header, sizeof(header));
358
	write_blocked(ext_header.buf, ext_header.len);
359
	strbuf_release(&ext_header);
360
}
361

362
static struct archiver **tar_filters;
363
static int nr_tar_filters;
364
static int alloc_tar_filters;
365

366
static struct archiver *find_tar_filter(const char *name, size_t len)
367
{
368
	int i;
369
	for (i = 0; i < nr_tar_filters; i++) {
370
		struct archiver *ar = tar_filters[i];
371
		if (!xstrncmpz(ar->name, name, len))
372
			return ar;
373
	}
374
	return NULL;
375
}
376

377
static int tar_filter_config(const char *var, const char *value,
378
			     void *data UNUSED)
379
{
380
	struct archiver *ar;
381
	const char *name;
382
	const char *type;
383
	size_t namelen;
384

385
	if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name)
386
		return 0;
387

388
	ar = find_tar_filter(name, namelen);
389
	if (!ar) {
390
		CALLOC_ARRAY(ar, 1);
391
		ar->name = xmemdupz(name, namelen);
392
		ar->write_archive = write_tar_filter_archive;
393
		ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS |
394
			    ARCHIVER_HIGH_COMPRESSION_LEVELS;
395
		ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
396
		tar_filters[nr_tar_filters++] = ar;
397
	}
398

399
	if (!strcmp(type, "command")) {
400
		if (!value)
401
			return config_error_nonbool(var);
402
		free(ar->filter_command);
403
		ar->filter_command = xstrdup(value);
404
		return 0;
405
	}
406
	if (!strcmp(type, "remote")) {
407
		if (git_config_bool(var, value))
408
			ar->flags |= ARCHIVER_REMOTE;
409
		else
410
			ar->flags &= ~ARCHIVER_REMOTE;
411
		return 0;
412
	}
413

414
	return 0;
415
}
416

417
static int git_tar_config(const char *var, const char *value,
418
			  const struct config_context *ctx, void *cb)
419
{
420
	if (!strcmp(var, "tar.umask")) {
421
		if (value && !strcmp(value, "user")) {
422
			tar_umask = umask(0);
423
			umask(tar_umask);
424
		} else {
425
			tar_umask = git_config_int(var, value, ctx->kvi);
426
		}
427
		return 0;
428
	}
429

430
	return tar_filter_config(var, value, cb);
431
}
432

433
static int write_tar_archive(const struct archiver *ar UNUSED,
434
			     struct archiver_args *args)
435
{
436
	int err = 0;
437

438
	write_global_extended_header(args);
439
	err = write_archive_entries(args, write_tar_entry);
440
	if (!err)
441
		write_trailer();
442
	return err;
443
}
444

445
static git_zstream gzstream;
446
static unsigned char outbuf[16384];
447

448
static void tgz_deflate(int flush)
449
{
450
	while (gzstream.avail_in || flush == Z_FINISH) {
451
		int status = git_deflate(&gzstream, flush);
452
		if (!gzstream.avail_out || status == Z_STREAM_END) {
453
			write_or_die(1, outbuf, gzstream.next_out - outbuf);
454
			gzstream.next_out = outbuf;
455
			gzstream.avail_out = sizeof(outbuf);
456
			if (status == Z_STREAM_END)
457
				break;
458
		}
459
		if (status != Z_OK && status != Z_BUF_ERROR)
460
			die(_("deflate error (%d)"), status);
461
	}
462
}
463

464
static void tgz_write_block(const void *data)
465
{
466
	gzstream.next_in = (void *)data;
467
	gzstream.avail_in = BLOCKSIZE;
468
	tgz_deflate(Z_NO_FLUSH);
469
}
470

471
static const char internal_gzip_command[] = "git archive gzip";
472

473
static int write_tar_filter_archive(const struct archiver *ar,
474
				    struct archiver_args *args)
475
{
476
#if ZLIB_VERNUM >= 0x1221
477
	struct gz_header_s gzhead = { .os = 3 }; /* Unix, for reproducibility */
478
#endif
479
	struct strbuf cmd = STRBUF_INIT;
480
	struct child_process filter = CHILD_PROCESS_INIT;
481
	int r;
482

483
	if (!ar->filter_command)
484
		BUG("tar-filter archiver called with no filter defined");
485

486
	if (!strcmp(ar->filter_command, internal_gzip_command)) {
487
		write_block = tgz_write_block;
488
		git_deflate_init_gzip(&gzstream, args->compression_level);
489
#if ZLIB_VERNUM >= 0x1221
490
		if (deflateSetHeader(&gzstream.z, &gzhead) != Z_OK)
491
			BUG("deflateSetHeader() called too late");
492
#endif
493
		gzstream.next_out = outbuf;
494
		gzstream.avail_out = sizeof(outbuf);
495

496
		r = write_tar_archive(ar, args);
497

498
		tgz_deflate(Z_FINISH);
499
		git_deflate_end(&gzstream);
500
		return r;
501
	}
502

503
	strbuf_addstr(&cmd, ar->filter_command);
504
	if (args->compression_level >= 0)
505
		strbuf_addf(&cmd, " -%d", args->compression_level);
506

507
	strvec_push(&filter.args, cmd.buf);
508
	filter.use_shell = 1;
509
	filter.in = -1;
510
	filter.silent_exec_failure = 1;
511

512
	if (start_command(&filter) < 0)
513
		die_errno(_("unable to start '%s' filter"), cmd.buf);
514
	close(1);
515
	if (dup2(filter.in, 1) < 0)
516
		die_errno(_("unable to redirect descriptor"));
517
	close(filter.in);
518

519
	r = write_tar_archive(ar, args);
520

521
	close(1);
522
	if (finish_command(&filter) != 0)
523
		die(_("'%s' filter reported error"), cmd.buf);
524

525
	strbuf_release(&cmd);
526
	return r;
527
}
528

529
static struct archiver tar_archiver = {
530
	.name = "tar",
531
	.write_archive = write_tar_archive,
532
	.flags = ARCHIVER_REMOTE,
533
};
534

535
void init_tar_archiver(void)
536
{
537
	int i;
538
	register_archiver(&tar_archiver);
539

540
	tar_filter_config("tar.tgz.command", internal_gzip_command, NULL);
541
	tar_filter_config("tar.tgz.remote", "true", NULL);
542
	tar_filter_config("tar.tar.gz.command", internal_gzip_command, NULL);
543
	tar_filter_config("tar.tar.gz.remote", "true", NULL);
544
	git_config(git_tar_config, NULL);
545
	for (i = 0; i < nr_tar_filters; i++) {
546
		/* omit any filters that never had a command configured */
547
		if (tar_filters[i]->filter_command)
548
			register_archiver(tar_filters[i]);
549
	}
550
}
551