2 * Copyright (c) 2005 Rene Scharfe
7 #define RECORDSIZE (512)
8 #define BLOCKSIZE (RECORDSIZE * 20)
10 #define TYPEFLAG_AUTO '\0'
11 #define TYPEFLAG_REG '0'
12 #define TYPEFLAG_LNK '2'
13 #define TYPEFLAG_DIR '5'
14 #define TYPEFLAG_GLOBAL_HEADER 'g'
15 #define TYPEFLAG_EXT_HEADER 'x'
17 #define EXT_HEADER_PATH 1
18 #define EXT_HEADER_LINKPATH 2
20 static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
22 static char block[BLOCKSIZE];
23 static unsigned long offset;
25 static const char *basedir;
26 static time_t archive_time;
29 struct path_prefix *prev;
33 /* tries hard to write, either succeeds or dies in the attempt */
34 static void reliable_write(void *buf, unsigned long size)
37 long ret = write(1, buf, size);
43 die("git-tar-tree: %s", strerror(errno));
45 die("git-tar-tree: disk full?");
52 /* writes out the whole block, but only if it is full */
53 static void write_if_needed(void)
55 if (offset == BLOCKSIZE) {
56 reliable_write(block, BLOCKSIZE);
61 /* acquire the next record from the buffer; user must call write_if_needed() */
62 static char *get_record(void)
64 char *p = block + offset;
65 memset(p, 0, RECORDSIZE);
71 * The end of tar archives is marked by 1024 nul bytes and after that
72 * follows the rest of the block (if any).
74 static void write_trailer(void)
87 * queues up writes, so that all our write(2) calls write exactly one
88 * full block; pads writes to RECORDSIZE
90 static void write_blocked(void *buf, unsigned long size)
95 unsigned long chunk = BLOCKSIZE - offset;
98 memcpy(block + offset, buf, chunk);
104 while (size >= BLOCKSIZE) {
105 reliable_write(buf, BLOCKSIZE);
110 memcpy(block + offset, buf, size);
114 tail = offset % RECORDSIZE;
116 memset(block + offset, 0, RECORDSIZE - tail);
117 offset += RECORDSIZE - tail;
122 static void append_string(char **p, const char *s)
124 unsigned int len = strlen(s);
129 static void append_char(char **p, char c)
135 static void append_path_prefix(char **buffer, struct path_prefix *prefix)
139 append_path_prefix(buffer, prefix->prev);
140 append_string(buffer, prefix->name);
141 append_char(buffer, '/');
144 static unsigned int path_prefix_len(struct path_prefix *prefix)
148 return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
151 static void append_path(char **p, int is_dir, const char *basepath,
152 struct path_prefix *prefix, const char *path)
155 append_string(p, basepath);
158 append_path_prefix(p, prefix);
159 append_string(p, path);
164 static unsigned int path_len(int is_dir, const char *basepath,
165 struct path_prefix *prefix, const char *path)
167 unsigned int len = 0;
169 len += strlen(basepath) + 1;
170 len += path_prefix_len(prefix) + strlen(path);
176 static void append_extended_header_prefix(char **p, unsigned int size,
179 int len = sprintf(*p, "%u %s=", size, keyword);
183 static unsigned int extended_header_len(const char *keyword,
184 unsigned int valuelen)
187 unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
195 static void append_extended_header(char **p, const char *keyword,
196 const char *value, unsigned int len)
198 unsigned int size = extended_header_len(keyword, len);
199 append_extended_header_prefix(p, size, keyword);
200 memcpy(*p, value, len);
202 append_char(p, '\n');
205 static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
206 const char *, unsigned int, void *, unsigned long);
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)
216 unsigned int pathlen, size, linkpathlen = 0;
218 size = pathlen = extended_header_len("path", namelen);
219 if (flags & EXT_HEADER_LINKPATH) {
220 linkpathlen = extended_header_len("linkpath", contentsize);
223 write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
224 0100600, NULL, size);
226 buffer = p = malloc(size);
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);
238 static void write_global_extended_header(const unsigned char *sha1)
243 size = extended_header_len("comment", 40);
244 write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
245 "pax_global_header", 0100600, NULL, size);
248 append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
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)
257 unsigned int namelen;
259 unsigned int checksum = 0;
261 unsigned int ext_header = 0;
263 if (typeflag == TYPEFLAG_AUTO) {
265 typeflag = TYPEFLAG_DIR;
266 else if (S_ISLNK(mode))
267 typeflag = TYPEFLAG_LNK;
269 typeflag = TYPEFLAG_REG;
272 namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
274 ext_header |= EXT_HEADER_PATH;
275 if (typeflag == TYPEFLAG_LNK && size > 100)
276 ext_header |= EXT_HEADER_LINKPATH;
278 /* the extended header must be written before the normal one */
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);
287 header = get_record();
290 sprintf(header, "%s.data", sha1_to_hex(sha1));
293 append_path(&p, S_ISDIR(mode), basepath, prefix, path);
296 if (typeflag == TYPEFLAG_LNK) {
297 if (ext_header & EXT_HEADER_LINKPATH) {
298 sprintf(&header[157], "see %s.paxheader",
302 strncpy(&header[157], buffer, size);
307 mode |= 0755; /* GIT doesn't store permissions of dirs */
309 mode |= 0777; /* ... nor of symlinks */
310 sprintf(&header[100], "%07o", mode & 07777);
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 */
318 if (S_ISDIR(mode) || S_ISLNK(mode))
320 sprintf(&header[124], "%011lo", size);
321 sprintf(&header[136], "%011lo", archive_time);
323 header[156] = typeflag;
325 memcpy(&header[257], "ustar", 6);
326 memcpy(&header[263], "00", 2);
328 sprintf(&header[329], "%07o", 0); /* devmajor */
329 sprintf(&header[337], "%07o", 0); /* devminor */
331 memset(&header[148], ' ', 8);
332 for (i = 0; i < RECORDSIZE; i++)
333 checksum += header[i];
334 sprintf(&header[148], "%07o", checksum & 0x1fffff);
339 static void traverse_tree(void *buffer, unsigned long size,
340 struct path_prefix *prefix)
342 struct path_prefix this_prefix;
343 this_prefix.prev = prefix;
346 int namelen = strlen(buffer)+1;
349 unsigned long eltsize;
350 unsigned char *sha1 = buffer + namelen;
351 char *path = strchr(buffer, ' ') + 1;
354 if (size < namelen + 20 || sscanf(buffer, "%o", &mode) != 1)
355 die("corrupt 'tree' file");
357 size -= namelen + 20;
359 eltbuf = read_sha1_file(sha1, elttype, &eltsize);
361 die("cannot read %s", sha1_to_hex(sha1));
362 write_header(sha1, TYPEFLAG_AUTO, basedir, prefix, path,
363 mode, eltbuf, eltsize);
364 if (!strcmp(elttype, "tree")) {
365 this_prefix.name = path;
366 traverse_tree(eltbuf, eltsize, &this_prefix);
367 } else if (!strcmp(elttype, "blob") && !S_ISLNK(mode)) {
368 write_blocked(eltbuf, eltsize);
374 /* get commit time from committer line of commit object */
375 static time_t commit_time(void * buffer, unsigned long size)
381 char *endp = memchr(p, '\n', size);
382 if (!endp || endp == p)
385 if (endp - p > 10 && !memcmp(p, "committer ", 10)) {
386 char *nump = strrchr(p, '>');
390 result = strtoul(nump, &endp, 10);
395 size -= endp - p - 1;
401 int main(int argc, char **argv)
403 unsigned char sha1[20];
404 unsigned char commit_sha1[20];
413 if (get_sha1(argv[1], sha1) < 0)
414 usage(tar_tree_usage);
417 usage(tar_tree_usage);
420 buffer = read_object_with_reference(sha1, "commit", &size, commit_sha1);
422 write_global_extended_header(commit_sha1);
423 archive_time = commit_time(buffer, size);
426 buffer = read_object_with_reference(sha1, "tree", &size, NULL);
428 die("not a reference to a tag, commit or tree object: %s",
431 archive_time = time(NULL);
433 write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
434 basedir, 040755, NULL, 0);
435 traverse_tree(buffer, size, NULL);