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1 | /* | |
2 | * Copyright (c) 2005, 2006 Rene Scharfe | |
3 | */ | |
4 | #include "cache.h" | |
5 | #include "config.h" | |
6 | #include "tar.h" | |
7 | #include "archive.h" | |
8 | #include "object-store.h" | |
9 | #include "streaming.h" | |
10 | #include "run-command.h" | |
11 | ||
12 | #define RECORDSIZE (512) | |
13 | #define BLOCKSIZE (RECORDSIZE * 20) | |
14 | ||
15 | static char block[BLOCKSIZE]; | |
16 | static unsigned long offset; | |
17 | ||
18 | static int tar_umask = 002; | |
19 | ||
20 | static int write_tar_filter_archive(const struct archiver *ar, | |
21 | struct archiver_args *args); | |
22 | ||
23 | /* | |
24 | * This is the max value that a ustar size header can specify, as it is fixed | |
25 | * at 11 octal digits. POSIX specifies that we switch to extended headers at | |
26 | * this size. | |
27 | * | |
28 | * Likewise for the mtime (which happens to use a buffer of the same size). | |
29 | */ | |
30 | #if ULONG_MAX == 0xFFFFFFFF | |
31 | #define USTAR_MAX_SIZE ULONG_MAX | |
32 | #else | |
33 | #define USTAR_MAX_SIZE 077777777777UL | |
34 | #endif | |
35 | #if TIME_MAX == 0xFFFFFFFF | |
36 | #define USTAR_MAX_MTIME TIME_MAX | |
37 | #else | |
38 | #define USTAR_MAX_MTIME 077777777777ULL | |
39 | #endif | |
40 | ||
41 | /* writes out the whole block, but only if it is full */ | |
42 | static void write_if_needed(void) | |
43 | { | |
44 | if (offset == BLOCKSIZE) { | |
45 | write_or_die(1, block, BLOCKSIZE); | |
46 | offset = 0; | |
47 | } | |
48 | } | |
49 | ||
50 | /* | |
51 | * queues up writes, so that all our write(2) calls write exactly one | |
52 | * full block; pads writes to RECORDSIZE | |
53 | */ | |
54 | static void do_write_blocked(const void *data, unsigned long size) | |
55 | { | |
56 | const char *buf = data; | |
57 | ||
58 | if (offset) { | |
59 | unsigned long chunk = BLOCKSIZE - offset; | |
60 | if (size < chunk) | |
61 | chunk = size; | |
62 | memcpy(block + offset, buf, chunk); | |
63 | size -= chunk; | |
64 | offset += chunk; | |
65 | buf += chunk; | |
66 | write_if_needed(); | |
67 | } | |
68 | while (size >= BLOCKSIZE) { | |
69 | write_or_die(1, buf, BLOCKSIZE); | |
70 | size -= BLOCKSIZE; | |
71 | buf += BLOCKSIZE; | |
72 | } | |
73 | if (size) { | |
74 | memcpy(block + offset, buf, size); | |
75 | offset += size; | |
76 | } | |
77 | } | |
78 | ||
79 | static void finish_record(void) | |
80 | { | |
81 | unsigned long tail; | |
82 | tail = offset % RECORDSIZE; | |
83 | if (tail) { | |
84 | memset(block + offset, 0, RECORDSIZE - tail); | |
85 | offset += RECORDSIZE - tail; | |
86 | } | |
87 | write_if_needed(); | |
88 | } | |
89 | ||
90 | static void write_blocked(const void *data, unsigned long size) | |
91 | { | |
92 | do_write_blocked(data, size); | |
93 | finish_record(); | |
94 | } | |
95 | ||
96 | /* | |
97 | * The end of tar archives is marked by 2*512 nul bytes and after that | |
98 | * follows the rest of the block (if any). | |
99 | */ | |
100 | static void write_trailer(void) | |
101 | { | |
102 | int tail = BLOCKSIZE - offset; | |
103 | memset(block + offset, 0, tail); | |
104 | write_or_die(1, block, BLOCKSIZE); | |
105 | if (tail < 2 * RECORDSIZE) { | |
106 | memset(block, 0, offset); | |
107 | write_or_die(1, block, BLOCKSIZE); | |
108 | } | |
109 | } | |
110 | ||
111 | /* | |
112 | * queues up writes, so that all our write(2) calls write exactly one | |
113 | * full block; pads writes to RECORDSIZE | |
114 | */ | |
115 | static int stream_blocked(const struct object_id *oid) | |
116 | { | |
117 | struct git_istream *st; | |
118 | enum object_type type; | |
119 | unsigned long sz; | |
120 | char buf[BLOCKSIZE]; | |
121 | ssize_t readlen; | |
122 | ||
123 | st = open_istream(oid, &type, &sz, NULL); | |
124 | if (!st) | |
125 | return error(_("cannot stream blob %s"), oid_to_hex(oid)); | |
126 | for (;;) { | |
127 | readlen = read_istream(st, buf, sizeof(buf)); | |
128 | if (readlen <= 0) | |
129 | break; | |
130 | do_write_blocked(buf, readlen); | |
131 | } | |
132 | close_istream(st); | |
133 | if (!readlen) | |
134 | finish_record(); | |
135 | return readlen; | |
136 | } | |
137 | ||
138 | /* | |
139 | * pax extended header records have the format "%u %s=%s\n". %u contains | |
140 | * the size of the whole string (including the %u), the first %s is the | |
141 | * keyword, the second one is the value. This function constructs such a | |
142 | * string and appends it to a struct strbuf. | |
143 | */ | |
144 | static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword, | |
145 | const char *value, size_t valuelen) | |
146 | { | |
147 | size_t orig_len = sb->len; | |
148 | size_t len, tmp; | |
149 | ||
150 | /* "%u %s=%s\n" */ | |
151 | len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1; | |
152 | for (tmp = 1; len / 10 >= tmp; tmp *= 10) | |
153 | len++; | |
154 | ||
155 | strbuf_grow(sb, len); | |
156 | strbuf_addf(sb, "%"PRIuMAX" %s=", (uintmax_t)len, keyword); | |
157 | strbuf_add(sb, value, valuelen); | |
158 | strbuf_addch(sb, '\n'); | |
159 | ||
160 | if (len != sb->len - orig_len) | |
161 | BUG("pax extended header length miscalculated as %"PRIuMAX | |
162 | ", should be %"PRIuMAX, | |
163 | (uintmax_t)len, (uintmax_t)(sb->len - orig_len)); | |
164 | } | |
165 | ||
166 | /* | |
167 | * Like strbuf_append_ext_header, but for numeric values. | |
168 | */ | |
169 | static void strbuf_append_ext_header_uint(struct strbuf *sb, | |
170 | const char *keyword, | |
171 | uintmax_t value) | |
172 | { | |
173 | char buf[40]; /* big enough for 2^128 in decimal, plus NUL */ | |
174 | int len; | |
175 | ||
176 | len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value); | |
177 | strbuf_append_ext_header(sb, keyword, buf, len); | |
178 | } | |
179 | ||
180 | static unsigned int ustar_header_chksum(const struct ustar_header *header) | |
181 | { | |
182 | const unsigned char *p = (const unsigned char *)header; | |
183 | unsigned int chksum = 0; | |
184 | while (p < (const unsigned char *)header->chksum) | |
185 | chksum += *p++; | |
186 | chksum += sizeof(header->chksum) * ' '; | |
187 | p += sizeof(header->chksum); | |
188 | while (p < (const unsigned char *)header + sizeof(struct ustar_header)) | |
189 | chksum += *p++; | |
190 | return chksum; | |
191 | } | |
192 | ||
193 | static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen) | |
194 | { | |
195 | size_t i = pathlen; | |
196 | if (i > 1 && path[i - 1] == '/') | |
197 | i--; | |
198 | if (i > maxlen) | |
199 | i = maxlen; | |
200 | do { | |
201 | i--; | |
202 | } while (i > 0 && path[i] != '/'); | |
203 | return i; | |
204 | } | |
205 | ||
206 | static void prepare_header(struct archiver_args *args, | |
207 | struct ustar_header *header, | |
208 | unsigned int mode, unsigned long size) | |
209 | { | |
210 | xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777); | |
211 | xsnprintf(header->size, sizeof(header->size), "%011"PRIoMAX , S_ISREG(mode) ? (uintmax_t)size : (uintmax_t)0); | |
212 | xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time); | |
213 | ||
214 | xsnprintf(header->uid, sizeof(header->uid), "%07o", 0); | |
215 | xsnprintf(header->gid, sizeof(header->gid), "%07o", 0); | |
216 | strlcpy(header->uname, "root", sizeof(header->uname)); | |
217 | strlcpy(header->gname, "root", sizeof(header->gname)); | |
218 | xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0); | |
219 | xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0); | |
220 | ||
221 | memcpy(header->magic, "ustar", 6); | |
222 | memcpy(header->version, "00", 2); | |
223 | ||
224 | xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header)); | |
225 | } | |
226 | ||
227 | static void write_extended_header(struct archiver_args *args, | |
228 | const struct object_id *oid, | |
229 | const void *buffer, unsigned long size) | |
230 | { | |
231 | struct ustar_header header; | |
232 | unsigned int mode; | |
233 | memset(&header, 0, sizeof(header)); | |
234 | *header.typeflag = TYPEFLAG_EXT_HEADER; | |
235 | mode = 0100666; | |
236 | xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid)); | |
237 | prepare_header(args, &header, mode, size); | |
238 | write_blocked(&header, sizeof(header)); | |
239 | write_blocked(buffer, size); | |
240 | } | |
241 | ||
242 | static int write_tar_entry(struct archiver_args *args, | |
243 | const struct object_id *oid, | |
244 | const char *path, size_t pathlen, | |
245 | unsigned int mode) | |
246 | { | |
247 | struct ustar_header header; | |
248 | struct strbuf ext_header = STRBUF_INIT; | |
249 | unsigned int old_mode = mode; | |
250 | unsigned long size, size_in_header; | |
251 | void *buffer; | |
252 | int err = 0; | |
253 | ||
254 | memset(&header, 0, sizeof(header)); | |
255 | ||
256 | if (S_ISDIR(mode) || S_ISGITLINK(mode)) { | |
257 | *header.typeflag = TYPEFLAG_DIR; | |
258 | mode = (mode | 0777) & ~tar_umask; | |
259 | } else if (S_ISLNK(mode)) { | |
260 | *header.typeflag = TYPEFLAG_LNK; | |
261 | mode |= 0777; | |
262 | } else if (S_ISREG(mode)) { | |
263 | *header.typeflag = TYPEFLAG_REG; | |
264 | mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask; | |
265 | } else { | |
266 | return error(_("unsupported file mode: 0%o (SHA1: %s)"), | |
267 | mode, oid_to_hex(oid)); | |
268 | } | |
269 | if (pathlen > sizeof(header.name)) { | |
270 | size_t plen = get_path_prefix(path, pathlen, | |
271 | sizeof(header.prefix)); | |
272 | size_t rest = pathlen - plen - 1; | |
273 | if (plen > 0 && rest <= sizeof(header.name)) { | |
274 | memcpy(header.prefix, path, plen); | |
275 | memcpy(header.name, path + plen + 1, rest); | |
276 | } else { | |
277 | xsnprintf(header.name, sizeof(header.name), "%s.data", | |
278 | oid_to_hex(oid)); | |
279 | strbuf_append_ext_header(&ext_header, "path", | |
280 | path, pathlen); | |
281 | } | |
282 | } else | |
283 | memcpy(header.name, path, pathlen); | |
284 | ||
285 | if (S_ISREG(mode) && !args->convert && | |
286 | oid_object_info(args->repo, oid, &size) == OBJ_BLOB && | |
287 | size > big_file_threshold) | |
288 | buffer = NULL; | |
289 | else if (S_ISLNK(mode) || S_ISREG(mode)) { | |
290 | enum object_type type; | |
291 | buffer = object_file_to_archive(args, path, oid, old_mode, &type, &size); | |
292 | if (!buffer) | |
293 | return error(_("cannot read %s"), oid_to_hex(oid)); | |
294 | } else { | |
295 | buffer = NULL; | |
296 | size = 0; | |
297 | } | |
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(oid); | |
328 | } | |
329 | free(buffer); | |
330 | return err; | |
331 | } | |
332 | ||
333 | static void write_global_extended_header(struct archiver_args *args) | |
334 | { | |
335 | const struct object_id *oid = args->commit_oid; | |
336 | struct strbuf ext_header = STRBUF_INIT; | |
337 | struct ustar_header header; | |
338 | unsigned int mode; | |
339 | ||
340 | if (oid) | |
341 | strbuf_append_ext_header(&ext_header, "comment", | |
342 | oid_to_hex(oid), | |
343 | the_hash_algo->hexsz); | |
344 | if (args->time > USTAR_MAX_MTIME) { | |
345 | strbuf_append_ext_header_uint(&ext_header, "mtime", | |
346 | args->time); | |
347 | args->time = USTAR_MAX_MTIME; | |
348 | } | |
349 | ||
350 | if (!ext_header.len) | |
351 | return; | |
352 | ||
353 | memset(&header, 0, sizeof(header)); | |
354 | *header.typeflag = TYPEFLAG_GLOBAL_HEADER; | |
355 | mode = 0100666; | |
356 | xsnprintf(header.name, sizeof(header.name), "pax_global_header"); | |
357 | prepare_header(args, &header, mode, ext_header.len); | |
358 | write_blocked(&header, sizeof(header)); | |
359 | write_blocked(ext_header.buf, ext_header.len); | |
360 | strbuf_release(&ext_header); | |
361 | } | |
362 | ||
363 | static struct archiver **tar_filters; | |
364 | static int nr_tar_filters; | |
365 | static int alloc_tar_filters; | |
366 | ||
367 | static struct archiver *find_tar_filter(const char *name, int len) | |
368 | { | |
369 | int i; | |
370 | for (i = 0; i < nr_tar_filters; i++) { | |
371 | struct archiver *ar = tar_filters[i]; | |
372 | if (!strncmp(ar->name, name, len) && !ar->name[len]) | |
373 | return ar; | |
374 | } | |
375 | return NULL; | |
376 | } | |
377 | ||
378 | static int tar_filter_config(const char *var, const char *value, void *data) | |
379 | { | |
380 | struct archiver *ar; | |
381 | const char *name; | |
382 | const char *type; | |
383 | int 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 | ar = xcalloc(1, sizeof(*ar)); | |
391 | ar->name = xmemdupz(name, namelen); | |
392 | ar->write_archive = write_tar_filter_archive; | |
393 | ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS; | |
394 | ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters); | |
395 | tar_filters[nr_tar_filters++] = ar; | |
396 | } | |
397 | ||
398 | if (!strcmp(type, "command")) { | |
399 | if (!value) | |
400 | return config_error_nonbool(var); | |
401 | free(ar->data); | |
402 | ar->data = xstrdup(value); | |
403 | return 0; | |
404 | } | |
405 | if (!strcmp(type, "remote")) { | |
406 | if (git_config_bool(var, value)) | |
407 | ar->flags |= ARCHIVER_REMOTE; | |
408 | else | |
409 | ar->flags &= ~ARCHIVER_REMOTE; | |
410 | return 0; | |
411 | } | |
412 | ||
413 | return 0; | |
414 | } | |
415 | ||
416 | static int git_tar_config(const char *var, const char *value, void *cb) | |
417 | { | |
418 | if (!strcmp(var, "tar.umask")) { | |
419 | if (value && !strcmp(value, "user")) { | |
420 | tar_umask = umask(0); | |
421 | umask(tar_umask); | |
422 | } else { | |
423 | tar_umask = git_config_int(var, value); | |
424 | } | |
425 | return 0; | |
426 | } | |
427 | ||
428 | return tar_filter_config(var, value, cb); | |
429 | } | |
430 | ||
431 | static int write_tar_archive(const struct archiver *ar, | |
432 | struct archiver_args *args) | |
433 | { | |
434 | int err = 0; | |
435 | ||
436 | write_global_extended_header(args); | |
437 | err = write_archive_entries(args, write_tar_entry); | |
438 | if (!err) | |
439 | write_trailer(); | |
440 | return err; | |
441 | } | |
442 | ||
443 | static int write_tar_filter_archive(const struct archiver *ar, | |
444 | struct archiver_args *args) | |
445 | { | |
446 | struct strbuf cmd = STRBUF_INIT; | |
447 | struct child_process filter = CHILD_PROCESS_INIT; | |
448 | const char *argv[2]; | |
449 | int r; | |
450 | ||
451 | if (!ar->data) | |
452 | BUG("tar-filter archiver called with no filter defined"); | |
453 | ||
454 | strbuf_addstr(&cmd, ar->data); | |
455 | if (args->compression_level >= 0) | |
456 | strbuf_addf(&cmd, " -%d", args->compression_level); | |
457 | ||
458 | argv[0] = cmd.buf; | |
459 | argv[1] = NULL; | |
460 | filter.argv = argv; | |
461 | filter.use_shell = 1; | |
462 | filter.in = -1; | |
463 | ||
464 | if (start_command(&filter) < 0) | |
465 | die_errno(_("unable to start '%s' filter"), argv[0]); | |
466 | close(1); | |
467 | if (dup2(filter.in, 1) < 0) | |
468 | die_errno(_("unable to redirect descriptor")); | |
469 | close(filter.in); | |
470 | ||
471 | r = write_tar_archive(ar, args); | |
472 | ||
473 | close(1); | |
474 | if (finish_command(&filter) != 0) | |
475 | die(_("'%s' filter reported error"), argv[0]); | |
476 | ||
477 | strbuf_release(&cmd); | |
478 | return r; | |
479 | } | |
480 | ||
481 | static struct archiver tar_archiver = { | |
482 | "tar", | |
483 | write_tar_archive, | |
484 | ARCHIVER_REMOTE | |
485 | }; | |
486 | ||
487 | void init_tar_archiver(void) | |
488 | { | |
489 | int i; | |
490 | register_archiver(&tar_archiver); | |
491 | ||
492 | tar_filter_config("tar.tgz.command", "gzip -cn", NULL); | |
493 | tar_filter_config("tar.tgz.remote", "true", NULL); | |
494 | tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL); | |
495 | tar_filter_config("tar.tar.gz.remote", "true", NULL); | |
496 | git_config(git_tar_config, NULL); | |
497 | for (i = 0; i < nr_tar_filters; i++) { | |
498 | /* omit any filters that never had a command configured */ | |
499 | if (tar_filters[i]->data) | |
500 | register_archiver(tar_filters[i]); | |
501 | } | |
502 | } |