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1 | /* | |
2 | * Copyright (c) 2005, 2006 Rene Scharfe | |
3 | */ | |
4 | #include "cache.h" | |
5 | #include "tar.h" | |
6 | #include "archive.h" | |
7 | #include "streaming.h" | |
8 | #include "run-command.h" | |
9 | ||
10 | #define RECORDSIZE (512) | |
11 | #define BLOCKSIZE (RECORDSIZE * 20) | |
12 | ||
13 | static char block[BLOCKSIZE]; | |
14 | static unsigned long offset; | |
15 | ||
16 | static int tar_umask = 002; | |
17 | ||
18 | static int write_tar_filter_archive(const struct archiver *ar, | |
19 | struct archiver_args *args); | |
20 | ||
21 | /* | |
22 | * This is the max value that a ustar size header can specify, as it is fixed | |
23 | * at 11 octal digits. POSIX specifies that we switch to extended headers at | |
24 | * this size. | |
25 | * | |
26 | * Likewise for the mtime (which happens to use a buffer of the same size). | |
27 | */ | |
28 | #if ULONG_MAX == 0xFFFFFFFF | |
29 | #define USTAR_MAX_SIZE ULONG_MAX | |
30 | #define USTAR_MAX_MTIME ULONG_MAX | |
31 | #else | |
32 | #define USTAR_MAX_SIZE 077777777777UL | |
33 | #define USTAR_MAX_MTIME 077777777777UL | |
34 | #endif | |
35 | ||
36 | /* writes out the whole block, but only if it is full */ | |
37 | static void write_if_needed(void) | |
38 | { | |
39 | if (offset == BLOCKSIZE) { | |
40 | write_or_die(1, block, BLOCKSIZE); | |
41 | offset = 0; | |
42 | } | |
43 | } | |
44 | ||
45 | /* | |
46 | * queues up writes, so that all our write(2) calls write exactly one | |
47 | * full block; pads writes to RECORDSIZE | |
48 | */ | |
49 | static void do_write_blocked(const void *data, unsigned long size) | |
50 | { | |
51 | const char *buf = data; | |
52 | ||
53 | if (offset) { | |
54 | unsigned long chunk = BLOCKSIZE - offset; | |
55 | if (size < chunk) | |
56 | chunk = size; | |
57 | memcpy(block + offset, buf, chunk); | |
58 | size -= chunk; | |
59 | offset += chunk; | |
60 | buf += chunk; | |
61 | write_if_needed(); | |
62 | } | |
63 | while (size >= BLOCKSIZE) { | |
64 | write_or_die(1, buf, BLOCKSIZE); | |
65 | size -= BLOCKSIZE; | |
66 | buf += BLOCKSIZE; | |
67 | } | |
68 | if (size) { | |
69 | memcpy(block + offset, buf, size); | |
70 | offset += size; | |
71 | } | |
72 | } | |
73 | ||
74 | static void finish_record(void) | |
75 | { | |
76 | unsigned long tail; | |
77 | tail = offset % RECORDSIZE; | |
78 | if (tail) { | |
79 | memset(block + offset, 0, RECORDSIZE - tail); | |
80 | offset += RECORDSIZE - tail; | |
81 | } | |
82 | write_if_needed(); | |
83 | } | |
84 | ||
85 | static void write_blocked(const void *data, unsigned long size) | |
86 | { | |
87 | do_write_blocked(data, size); | |
88 | finish_record(); | |
89 | } | |
90 | ||
91 | /* | |
92 | * The end of tar archives is marked by 2*512 nul bytes and after that | |
93 | * follows the rest of the block (if any). | |
94 | */ | |
95 | static void write_trailer(void) | |
96 | { | |
97 | int tail = BLOCKSIZE - offset; | |
98 | memset(block + offset, 0, tail); | |
99 | write_or_die(1, block, BLOCKSIZE); | |
100 | if (tail < 2 * RECORDSIZE) { | |
101 | memset(block, 0, offset); | |
102 | write_or_die(1, block, BLOCKSIZE); | |
103 | } | |
104 | } | |
105 | ||
106 | /* | |
107 | * queues up writes, so that all our write(2) calls write exactly one | |
108 | * full block; pads writes to RECORDSIZE | |
109 | */ | |
110 | static int stream_blocked(const unsigned char *sha1) | |
111 | { | |
112 | struct git_istream *st; | |
113 | enum object_type type; | |
114 | unsigned long sz; | |
115 | char buf[BLOCKSIZE]; | |
116 | ssize_t readlen; | |
117 | ||
118 | st = open_istream(sha1, &type, &sz, NULL); | |
119 | if (!st) | |
120 | return error("cannot stream blob %s", sha1_to_hex(sha1)); | |
121 | for (;;) { | |
122 | readlen = read_istream(st, buf, sizeof(buf)); | |
123 | if (readlen <= 0) | |
124 | break; | |
125 | do_write_blocked(buf, readlen); | |
126 | } | |
127 | close_istream(st); | |
128 | if (!readlen) | |
129 | finish_record(); | |
130 | return readlen; | |
131 | } | |
132 | ||
133 | /* | |
134 | * pax extended header records have the format "%u %s=%s\n". %u contains | |
135 | * the size of the whole string (including the %u), the first %s is the | |
136 | * keyword, the second one is the value. This function constructs such a | |
137 | * string and appends it to a struct strbuf. | |
138 | */ | |
139 | static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword, | |
140 | const char *value, unsigned int valuelen) | |
141 | { | |
142 | int len, tmp; | |
143 | ||
144 | /* "%u %s=%s\n" */ | |
145 | len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1; | |
146 | for (tmp = len; tmp > 9; tmp /= 10) | |
147 | len++; | |
148 | ||
149 | strbuf_grow(sb, len); | |
150 | strbuf_addf(sb, "%u %s=", len, keyword); | |
151 | strbuf_add(sb, value, valuelen); | |
152 | strbuf_addch(sb, '\n'); | |
153 | } | |
154 | ||
155 | /* | |
156 | * Like strbuf_append_ext_header, but for numeric values. | |
157 | */ | |
158 | static void strbuf_append_ext_header_uint(struct strbuf *sb, | |
159 | const char *keyword, | |
160 | uintmax_t value) | |
161 | { | |
162 | char buf[40]; /* big enough for 2^128 in decimal, plus NUL */ | |
163 | int len; | |
164 | ||
165 | len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value); | |
166 | strbuf_append_ext_header(sb, keyword, buf, len); | |
167 | } | |
168 | ||
169 | static unsigned int ustar_header_chksum(const struct ustar_header *header) | |
170 | { | |
171 | const unsigned char *p = (const unsigned char *)header; | |
172 | unsigned int chksum = 0; | |
173 | while (p < (const unsigned char *)header->chksum) | |
174 | chksum += *p++; | |
175 | chksum += sizeof(header->chksum) * ' '; | |
176 | p += sizeof(header->chksum); | |
177 | while (p < (const unsigned char *)header + sizeof(struct ustar_header)) | |
178 | chksum += *p++; | |
179 | return chksum; | |
180 | } | |
181 | ||
182 | static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen) | |
183 | { | |
184 | size_t i = pathlen; | |
185 | if (i > 1 && path[i - 1] == '/') | |
186 | i--; | |
187 | if (i > maxlen) | |
188 | i = maxlen; | |
189 | do { | |
190 | i--; | |
191 | } while (i > 0 && path[i] != '/'); | |
192 | return i; | |
193 | } | |
194 | ||
195 | static void prepare_header(struct archiver_args *args, | |
196 | struct ustar_header *header, | |
197 | unsigned int mode, unsigned long size) | |
198 | { | |
199 | xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777); | |
200 | xsnprintf(header->size, sizeof(header->size), "%011lo", S_ISREG(mode) ? size : 0); | |
201 | xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time); | |
202 | ||
203 | xsnprintf(header->uid, sizeof(header->uid), "%07o", 0); | |
204 | xsnprintf(header->gid, sizeof(header->gid), "%07o", 0); | |
205 | strlcpy(header->uname, "root", sizeof(header->uname)); | |
206 | strlcpy(header->gname, "root", sizeof(header->gname)); | |
207 | xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0); | |
208 | xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0); | |
209 | ||
210 | memcpy(header->magic, "ustar", 6); | |
211 | memcpy(header->version, "00", 2); | |
212 | ||
213 | xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header)); | |
214 | } | |
215 | ||
216 | static void write_extended_header(struct archiver_args *args, | |
217 | const unsigned char *sha1, | |
218 | const void *buffer, unsigned long size) | |
219 | { | |
220 | struct ustar_header header; | |
221 | unsigned int mode; | |
222 | memset(&header, 0, sizeof(header)); | |
223 | *header.typeflag = TYPEFLAG_EXT_HEADER; | |
224 | mode = 0100666; | |
225 | xsnprintf(header.name, sizeof(header.name), "%s.paxheader", sha1_to_hex(sha1)); | |
226 | prepare_header(args, &header, mode, size); | |
227 | write_blocked(&header, sizeof(header)); | |
228 | write_blocked(buffer, size); | |
229 | } | |
230 | ||
231 | static int write_tar_entry(struct archiver_args *args, | |
232 | const unsigned char *sha1, | |
233 | const char *path, size_t pathlen, | |
234 | unsigned int mode) | |
235 | { | |
236 | struct ustar_header header; | |
237 | struct strbuf ext_header = STRBUF_INIT; | |
238 | unsigned int old_mode = mode; | |
239 | unsigned long size, size_in_header; | |
240 | void *buffer; | |
241 | int err = 0; | |
242 | ||
243 | memset(&header, 0, sizeof(header)); | |
244 | ||
245 | if (S_ISDIR(mode) || S_ISGITLINK(mode)) { | |
246 | *header.typeflag = TYPEFLAG_DIR; | |
247 | mode = (mode | 0777) & ~tar_umask; | |
248 | } else if (S_ISLNK(mode)) { | |
249 | *header.typeflag = TYPEFLAG_LNK; | |
250 | mode |= 0777; | |
251 | } else if (S_ISREG(mode)) { | |
252 | *header.typeflag = TYPEFLAG_REG; | |
253 | mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask; | |
254 | } else { | |
255 | return error("unsupported file mode: 0%o (SHA1: %s)", | |
256 | mode, sha1_to_hex(sha1)); | |
257 | } | |
258 | if (pathlen > sizeof(header.name)) { | |
259 | size_t plen = get_path_prefix(path, pathlen, | |
260 | sizeof(header.prefix)); | |
261 | size_t rest = pathlen - plen - 1; | |
262 | if (plen > 0 && rest <= sizeof(header.name)) { | |
263 | memcpy(header.prefix, path, plen); | |
264 | memcpy(header.name, path + plen + 1, rest); | |
265 | } else { | |
266 | xsnprintf(header.name, sizeof(header.name), "%s.data", | |
267 | sha1_to_hex(sha1)); | |
268 | strbuf_append_ext_header(&ext_header, "path", | |
269 | path, pathlen); | |
270 | } | |
271 | } else | |
272 | memcpy(header.name, path, pathlen); | |
273 | ||
274 | if (S_ISREG(mode) && !args->convert && | |
275 | sha1_object_info(sha1, &size) == OBJ_BLOB && | |
276 | size > big_file_threshold) | |
277 | buffer = NULL; | |
278 | else if (S_ISLNK(mode) || S_ISREG(mode)) { | |
279 | enum object_type type; | |
280 | buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size); | |
281 | if (!buffer) | |
282 | return error("cannot read %s", sha1_to_hex(sha1)); | |
283 | } else { | |
284 | buffer = NULL; | |
285 | size = 0; | |
286 | } | |
287 | ||
288 | if (S_ISLNK(mode)) { | |
289 | if (size > sizeof(header.linkname)) { | |
290 | xsnprintf(header.linkname, sizeof(header.linkname), | |
291 | "see %s.paxheader", sha1_to_hex(sha1)); | |
292 | strbuf_append_ext_header(&ext_header, "linkpath", | |
293 | buffer, size); | |
294 | } else | |
295 | memcpy(header.linkname, buffer, size); | |
296 | } | |
297 | ||
298 | size_in_header = size; | |
299 | if (S_ISREG(mode) && size > USTAR_MAX_SIZE) { | |
300 | size_in_header = 0; | |
301 | strbuf_append_ext_header_uint(&ext_header, "size", size); | |
302 | } | |
303 | ||
304 | prepare_header(args, &header, mode, size_in_header); | |
305 | ||
306 | if (ext_header.len > 0) { | |
307 | write_extended_header(args, sha1, ext_header.buf, | |
308 | ext_header.len); | |
309 | } | |
310 | strbuf_release(&ext_header); | |
311 | write_blocked(&header, sizeof(header)); | |
312 | if (S_ISREG(mode) && size > 0) { | |
313 | if (buffer) | |
314 | write_blocked(buffer, size); | |
315 | else | |
316 | err = stream_blocked(sha1); | |
317 | } | |
318 | free(buffer); | |
319 | return err; | |
320 | } | |
321 | ||
322 | static void write_global_extended_header(struct archiver_args *args) | |
323 | { | |
324 | const unsigned char *sha1 = args->commit_sha1; | |
325 | struct strbuf ext_header = STRBUF_INIT; | |
326 | struct ustar_header header; | |
327 | unsigned int mode; | |
328 | ||
329 | if (sha1) | |
330 | strbuf_append_ext_header(&ext_header, "comment", | |
331 | sha1_to_hex(sha1), 40); | |
332 | if (args->time > USTAR_MAX_MTIME) { | |
333 | strbuf_append_ext_header_uint(&ext_header, "mtime", | |
334 | args->time); | |
335 | args->time = USTAR_MAX_MTIME; | |
336 | } | |
337 | ||
338 | if (!ext_header.len) | |
339 | return; | |
340 | ||
341 | memset(&header, 0, sizeof(header)); | |
342 | *header.typeflag = TYPEFLAG_GLOBAL_HEADER; | |
343 | mode = 0100666; | |
344 | xsnprintf(header.name, sizeof(header.name), "pax_global_header"); | |
345 | prepare_header(args, &header, mode, ext_header.len); | |
346 | write_blocked(&header, sizeof(header)); | |
347 | write_blocked(ext_header.buf, ext_header.len); | |
348 | strbuf_release(&ext_header); | |
349 | } | |
350 | ||
351 | static struct archiver **tar_filters; | |
352 | static int nr_tar_filters; | |
353 | static int alloc_tar_filters; | |
354 | ||
355 | static struct archiver *find_tar_filter(const char *name, int len) | |
356 | { | |
357 | int i; | |
358 | for (i = 0; i < nr_tar_filters; i++) { | |
359 | struct archiver *ar = tar_filters[i]; | |
360 | if (!strncmp(ar->name, name, len) && !ar->name[len]) | |
361 | return ar; | |
362 | } | |
363 | return NULL; | |
364 | } | |
365 | ||
366 | static int tar_filter_config(const char *var, const char *value, void *data) | |
367 | { | |
368 | struct archiver *ar; | |
369 | const char *name; | |
370 | const char *type; | |
371 | int namelen; | |
372 | ||
373 | if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name) | |
374 | return 0; | |
375 | ||
376 | ar = find_tar_filter(name, namelen); | |
377 | if (!ar) { | |
378 | ar = xcalloc(1, sizeof(*ar)); | |
379 | ar->name = xmemdupz(name, namelen); | |
380 | ar->write_archive = write_tar_filter_archive; | |
381 | ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS; | |
382 | ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters); | |
383 | tar_filters[nr_tar_filters++] = ar; | |
384 | } | |
385 | ||
386 | if (!strcmp(type, "command")) { | |
387 | if (!value) | |
388 | return config_error_nonbool(var); | |
389 | free(ar->data); | |
390 | ar->data = xstrdup(value); | |
391 | return 0; | |
392 | } | |
393 | if (!strcmp(type, "remote")) { | |
394 | if (git_config_bool(var, value)) | |
395 | ar->flags |= ARCHIVER_REMOTE; | |
396 | else | |
397 | ar->flags &= ~ARCHIVER_REMOTE; | |
398 | return 0; | |
399 | } | |
400 | ||
401 | return 0; | |
402 | } | |
403 | ||
404 | static int git_tar_config(const char *var, const char *value, void *cb) | |
405 | { | |
406 | if (!strcmp(var, "tar.umask")) { | |
407 | if (value && !strcmp(value, "user")) { | |
408 | tar_umask = umask(0); | |
409 | umask(tar_umask); | |
410 | } else { | |
411 | tar_umask = git_config_int(var, value); | |
412 | } | |
413 | return 0; | |
414 | } | |
415 | ||
416 | return tar_filter_config(var, value, cb); | |
417 | } | |
418 | ||
419 | static int write_tar_archive(const struct archiver *ar, | |
420 | struct archiver_args *args) | |
421 | { | |
422 | int err = 0; | |
423 | ||
424 | write_global_extended_header(args); | |
425 | err = write_archive_entries(args, write_tar_entry); | |
426 | if (!err) | |
427 | write_trailer(); | |
428 | return err; | |
429 | } | |
430 | ||
431 | static int write_tar_filter_archive(const struct archiver *ar, | |
432 | struct archiver_args *args) | |
433 | { | |
434 | struct strbuf cmd = STRBUF_INIT; | |
435 | struct child_process filter = CHILD_PROCESS_INIT; | |
436 | const char *argv[2]; | |
437 | int r; | |
438 | ||
439 | if (!ar->data) | |
440 | die("BUG: tar-filter archiver called with no filter defined"); | |
441 | ||
442 | strbuf_addstr(&cmd, ar->data); | |
443 | if (args->compression_level >= 0) | |
444 | strbuf_addf(&cmd, " -%d", args->compression_level); | |
445 | ||
446 | argv[0] = cmd.buf; | |
447 | argv[1] = NULL; | |
448 | filter.argv = argv; | |
449 | filter.use_shell = 1; | |
450 | filter.in = -1; | |
451 | ||
452 | if (start_command(&filter) < 0) | |
453 | die_errno("unable to start '%s' filter", argv[0]); | |
454 | close(1); | |
455 | if (dup2(filter.in, 1) < 0) | |
456 | die_errno("unable to redirect descriptor"); | |
457 | close(filter.in); | |
458 | ||
459 | r = write_tar_archive(ar, args); | |
460 | ||
461 | close(1); | |
462 | if (finish_command(&filter) != 0) | |
463 | die("'%s' filter reported error", argv[0]); | |
464 | ||
465 | strbuf_release(&cmd); | |
466 | return r; | |
467 | } | |
468 | ||
469 | static struct archiver tar_archiver = { | |
470 | "tar", | |
471 | write_tar_archive, | |
472 | ARCHIVER_REMOTE | |
473 | }; | |
474 | ||
475 | void init_tar_archiver(void) | |
476 | { | |
477 | int i; | |
478 | register_archiver(&tar_archiver); | |
479 | ||
480 | tar_filter_config("tar.tgz.command", "gzip -cn", NULL); | |
481 | tar_filter_config("tar.tgz.remote", "true", NULL); | |
482 | tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL); | |
483 | tar_filter_config("tar.tar.gz.remote", "true", NULL); | |
484 | git_config(git_tar_config, NULL); | |
485 | for (i = 0; i < nr_tar_filters; i++) { | |
486 | /* omit any filters that never had a command configured */ | |
487 | if (tar_filters[i]->data) | |
488 | register_archiver(tar_filters[i]); | |
489 | } | |
490 | } |