contrib/git-svn: fix a copied-tree bug in an overzealous assertion
[git/git.git] / tar-tree.c
1 /*
2 * Copyright (c) 2005 Rene Scharfe
3 */
4 #include <time.h>
5 #include "cache.h"
6 #include "diff.h"
7 #include "commit.h"
8
9 #define RECORDSIZE (512)
10 #define BLOCKSIZE (RECORDSIZE * 20)
11
12 #define TYPEFLAG_AUTO '\0'
13 #define TYPEFLAG_REG '0'
14 #define TYPEFLAG_LNK '2'
15 #define TYPEFLAG_DIR '5'
16 #define TYPEFLAG_GLOBAL_HEADER 'g'
17 #define TYPEFLAG_EXT_HEADER 'x'
18
19 #define EXT_HEADER_PATH 1
20 #define EXT_HEADER_LINKPATH 2
21
22 static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
23
24 static char block[BLOCKSIZE];
25 static unsigned long offset;
26
27 static const char *basedir;
28 static time_t archive_time;
29
30 struct path_prefix {
31 struct path_prefix *prev;
32 const char *name;
33 };
34
35 /* tries hard to write, either succeeds or dies in the attempt */
36 static void reliable_write(void *buf, unsigned long size)
37 {
38 while (size > 0) {
39 long ret = xwrite(1, buf, size);
40 if (ret < 0) {
41 if (errno == EPIPE)
42 exit(0);
43 die("git-tar-tree: %s", strerror(errno));
44 } else if (!ret) {
45 die("git-tar-tree: disk full?");
46 }
47 size -= ret;
48 buf += ret;
49 }
50 }
51
52 /* writes out the whole block, but only if it is full */
53 static void write_if_needed(void)
54 {
55 if (offset == BLOCKSIZE) {
56 reliable_write(block, BLOCKSIZE);
57 offset = 0;
58 }
59 }
60
61 /* acquire the next record from the buffer; user must call write_if_needed() */
62 static char *get_record(void)
63 {
64 char *p = block + offset;
65 memset(p, 0, RECORDSIZE);
66 offset += RECORDSIZE;
67 return p;
68 }
69
70 /*
71 * The end of tar archives is marked by 1024 nul bytes and after that
72 * follows the rest of the block (if any).
73 */
74 static void write_trailer(void)
75 {
76 get_record();
77 write_if_needed();
78 get_record();
79 write_if_needed();
80 while (offset) {
81 get_record();
82 write_if_needed();
83 }
84 }
85
86 /*
87 * queues up writes, so that all our write(2) calls write exactly one
88 * full block; pads writes to RECORDSIZE
89 */
90 static void write_blocked(void *buf, unsigned long size)
91 {
92 unsigned long tail;
93
94 if (offset) {
95 unsigned long chunk = BLOCKSIZE - offset;
96 if (size < chunk)
97 chunk = size;
98 memcpy(block + offset, buf, chunk);
99 size -= chunk;
100 offset += chunk;
101 buf += chunk;
102 write_if_needed();
103 }
104 while (size >= BLOCKSIZE) {
105 reliable_write(buf, BLOCKSIZE);
106 size -= BLOCKSIZE;
107 buf += BLOCKSIZE;
108 }
109 if (size) {
110 memcpy(block + offset, buf, size);
111 buf += size;
112 offset += size;
113 }
114 tail = offset % RECORDSIZE;
115 if (tail) {
116 memset(block + offset, 0, RECORDSIZE - tail);
117 offset += RECORDSIZE - tail;
118 }
119 write_if_needed();
120 }
121
122 static void append_string(char **p, const char *s)
123 {
124 unsigned int len = strlen(s);
125 memcpy(*p, s, len);
126 *p += len;
127 }
128
129 static void append_char(char **p, char c)
130 {
131 **p = c;
132 *p += 1;
133 }
134
135 static void append_path_prefix(char **buffer, struct path_prefix *prefix)
136 {
137 if (!prefix)
138 return;
139 append_path_prefix(buffer, prefix->prev);
140 append_string(buffer, prefix->name);
141 append_char(buffer, '/');
142 }
143
144 static unsigned int path_prefix_len(struct path_prefix *prefix)
145 {
146 if (!prefix)
147 return 0;
148 return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
149 }
150
151 static void append_path(char **p, int is_dir, const char *basepath,
152 struct path_prefix *prefix, const char *path)
153 {
154 if (basepath) {
155 append_string(p, basepath);
156 append_char(p, '/');
157 }
158 append_path_prefix(p, prefix);
159 append_string(p, path);
160 if (is_dir)
161 append_char(p, '/');
162 }
163
164 static unsigned int path_len(int is_dir, const char *basepath,
165 struct path_prefix *prefix, const char *path)
166 {
167 unsigned int len = 0;
168 if (basepath)
169 len += strlen(basepath) + 1;
170 len += path_prefix_len(prefix) + strlen(path);
171 if (is_dir)
172 len++;
173 return len;
174 }
175
176 static void append_extended_header_prefix(char **p, unsigned int size,
177 const char *keyword)
178 {
179 int len = sprintf(*p, "%u %s=", size, keyword);
180 *p += len;
181 }
182
183 static unsigned int extended_header_len(const char *keyword,
184 unsigned int valuelen)
185 {
186 /* "%u %s=%s\n" */
187 unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
188 if (len > 9)
189 len++;
190 if (len > 99)
191 len++;
192 return len;
193 }
194
195 static void append_extended_header(char **p, const char *keyword,
196 const char *value, unsigned int len)
197 {
198 unsigned int size = extended_header_len(keyword, len);
199 append_extended_header_prefix(p, size, keyword);
200 memcpy(*p, value, len);
201 *p += len;
202 append_char(p, '\n');
203 }
204
205 static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
206 const char *, unsigned int, void *, unsigned long);
207
208 /* stores a pax extended header directly in the block buffer */
209 static void write_extended_header(const char *headerfilename, int is_dir,
210 unsigned int flags, const char *basepath,
211 struct path_prefix *prefix,
212 const char *path, unsigned int namelen,
213 void *content, unsigned int contentsize)
214 {
215 char *buffer, *p;
216 unsigned int pathlen, size, linkpathlen = 0;
217
218 size = pathlen = extended_header_len("path", namelen);
219 if (flags & EXT_HEADER_LINKPATH) {
220 linkpathlen = extended_header_len("linkpath", contentsize);
221 size += linkpathlen;
222 }
223 write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
224 0100600, NULL, size);
225
226 buffer = p = malloc(size);
227 if (!buffer)
228 die("git-tar-tree: %s", strerror(errno));
229 append_extended_header_prefix(&p, pathlen, "path");
230 append_path(&p, is_dir, basepath, prefix, path);
231 append_char(&p, '\n');
232 if (flags & EXT_HEADER_LINKPATH)
233 append_extended_header(&p, "linkpath", content, contentsize);
234 write_blocked(buffer, size);
235 free(buffer);
236 }
237
238 static void write_global_extended_header(const unsigned char *sha1)
239 {
240 char *p;
241 unsigned int size;
242
243 size = extended_header_len("comment", 40);
244 write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
245 "pax_global_header", 0100600, NULL, size);
246
247 p = get_record();
248 append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
249 write_if_needed();
250 }
251
252 /* stores a ustar header directly in the block buffer */
253 static void write_header(const unsigned char *sha1, char typeflag, const char *basepath,
254 struct path_prefix *prefix, const char *path,
255 unsigned int mode, void *buffer, unsigned long size)
256 {
257 unsigned int namelen;
258 char *header = NULL;
259 unsigned int checksum = 0;
260 int i;
261 unsigned int ext_header = 0;
262
263 if (typeflag == TYPEFLAG_AUTO) {
264 if (S_ISDIR(mode))
265 typeflag = TYPEFLAG_DIR;
266 else if (S_ISLNK(mode))
267 typeflag = TYPEFLAG_LNK;
268 else
269 typeflag = TYPEFLAG_REG;
270 }
271
272 namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
273 if (namelen > 100)
274 ext_header |= EXT_HEADER_PATH;
275 if (typeflag == TYPEFLAG_LNK && size > 100)
276 ext_header |= EXT_HEADER_LINKPATH;
277
278 /* the extended header must be written before the normal one */
279 if (ext_header) {
280 char headerfilename[51];
281 sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
282 write_extended_header(headerfilename, S_ISDIR(mode),
283 ext_header, basepath, prefix, path,
284 namelen, buffer, size);
285 }
286
287 header = get_record();
288
289 if (ext_header) {
290 sprintf(header, "%s.data", sha1_to_hex(sha1));
291 } else {
292 char *p = header;
293 append_path(&p, S_ISDIR(mode), basepath, prefix, path);
294 }
295
296 if (typeflag == TYPEFLAG_LNK) {
297 if (ext_header & EXT_HEADER_LINKPATH) {
298 sprintf(&header[157], "see %s.paxheader",
299 sha1_to_hex(sha1));
300 } else {
301 if (buffer)
302 strncpy(&header[157], buffer, size);
303 }
304 }
305
306 if (S_ISDIR(mode))
307 mode |= 0755; /* GIT doesn't store permissions of dirs */
308 if (S_ISLNK(mode))
309 mode |= 0777; /* ... nor of symlinks */
310 sprintf(&header[100], "%07o", mode & 07777);
311
312 /* XXX: should we provide more meaningful info here? */
313 sprintf(&header[108], "%07o", 0); /* uid */
314 sprintf(&header[116], "%07o", 0); /* gid */
315 strncpy(&header[265], "git", 31); /* uname */
316 strncpy(&header[297], "git", 31); /* gname */
317
318 if (S_ISDIR(mode) || S_ISLNK(mode))
319 size = 0;
320 sprintf(&header[124], "%011lo", size);
321 sprintf(&header[136], "%011lo", archive_time);
322
323 header[156] = typeflag;
324
325 memcpy(&header[257], "ustar", 6);
326 memcpy(&header[263], "00", 2);
327
328 sprintf(&header[329], "%07o", 0); /* devmajor */
329 sprintf(&header[337], "%07o", 0); /* devminor */
330
331 memset(&header[148], ' ', 8);
332 for (i = 0; i < RECORDSIZE; i++)
333 checksum += header[i];
334 sprintf(&header[148], "%07o", checksum & 0x1fffff);
335
336 write_if_needed();
337 }
338
339 static void traverse_tree(struct tree_desc *tree,
340 struct path_prefix *prefix)
341 {
342 struct path_prefix this_prefix;
343 this_prefix.prev = prefix;
344
345 while (tree->size) {
346 const char *name;
347 const unsigned char *sha1;
348 unsigned mode;
349 void *eltbuf;
350 char elttype[20];
351 unsigned long eltsize;
352
353 sha1 = tree_entry_extract(tree, &name, &mode);
354 update_tree_entry(tree);
355
356 eltbuf = read_sha1_file(sha1, elttype, &eltsize);
357 if (!eltbuf)
358 die("cannot read %s", sha1_to_hex(sha1));
359 write_header(sha1, TYPEFLAG_AUTO, basedir,
360 prefix, name, mode, eltbuf, eltsize);
361 if (S_ISDIR(mode)) {
362 struct tree_desc subtree;
363 subtree.buf = eltbuf;
364 subtree.size = eltsize;
365 this_prefix.name = name;
366 traverse_tree(&subtree, &this_prefix);
367 } else if (!S_ISLNK(mode)) {
368 write_blocked(eltbuf, eltsize);
369 }
370 free(eltbuf);
371 }
372 }
373
374 int main(int argc, char **argv)
375 {
376 unsigned char sha1[20];
377 struct commit *commit;
378 struct tree_desc tree;
379
380 setup_git_directory();
381
382 switch (argc) {
383 case 3:
384 basedir = argv[2];
385 /* FALLTHROUGH */
386 case 2:
387 if (get_sha1(argv[1], sha1) < 0)
388 usage(tar_tree_usage);
389 break;
390 default:
391 usage(tar_tree_usage);
392 }
393
394 commit = lookup_commit_reference(sha1);
395 if (commit) {
396 write_global_extended_header(commit->object.sha1);
397 archive_time = commit->date;
398 }
399 tree.buf = read_object_with_reference(sha1, "tree", &tree.size, NULL);
400 if (!tree.buf)
401 die("not a reference to a tag, commit or tree object: %s",
402 sha1_to_hex(sha1));
403 if (!archive_time)
404 archive_time = time(NULL);
405 if (basedir)
406 write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
407 basedir, 040777, NULL, 0);
408 traverse_tree(&tree, NULL);
409 write_trailer();
410 return 0;
411 }