tree_entry(): new tree-walking helper function
[git/git.git] / builtin-tar-tree.c
1 /*
2 * Copyright (c) 2005, 2006 Rene Scharfe
3 */
4 #include <time.h>
5 #include "cache.h"
6 #include "tree-walk.h"
7 #include "commit.h"
8 #include "strbuf.h"
9 #include "tar.h"
10 #include "builtin.h"
11 #include "pkt-line.h"
12
13 #define RECORDSIZE (512)
14 #define BLOCKSIZE (RECORDSIZE * 20)
15
16 static const char tar_tree_usage[] =
17 "git-tar-tree [--remote=<repo>] <ent> [basedir]";
18
19 static char block[BLOCKSIZE];
20 static unsigned long offset;
21
22 static time_t archive_time;
23
24 /* tries hard to write, either succeeds or dies in the attempt */
25 static void reliable_write(void *buf, unsigned long size)
26 {
27 while (size > 0) {
28 long ret = xwrite(1, buf, size);
29 if (ret < 0) {
30 if (errno == EPIPE)
31 exit(0);
32 die("git-tar-tree: %s", strerror(errno));
33 } else if (!ret) {
34 die("git-tar-tree: disk full?");
35 }
36 size -= ret;
37 buf += ret;
38 }
39 }
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 reliable_write(block, BLOCKSIZE);
46 offset = 0;
47 }
48 }
49
50 /* acquire the next record from the buffer; user must call write_if_needed() */
51 static char *get_record(void)
52 {
53 char *p = block + offset;
54 memset(p, 0, RECORDSIZE);
55 offset += RECORDSIZE;
56 return p;
57 }
58
59 /*
60 * The end of tar archives is marked by 1024 nul bytes and after that
61 * follows the rest of the block (if any).
62 */
63 static void write_trailer(void)
64 {
65 get_record();
66 write_if_needed();
67 get_record();
68 write_if_needed();
69 while (offset) {
70 get_record();
71 write_if_needed();
72 }
73 }
74
75 /*
76 * queues up writes, so that all our write(2) calls write exactly one
77 * full block; pads writes to RECORDSIZE
78 */
79 static void write_blocked(void *buf, unsigned long size)
80 {
81 unsigned long tail;
82
83 if (offset) {
84 unsigned long chunk = BLOCKSIZE - offset;
85 if (size < chunk)
86 chunk = size;
87 memcpy(block + offset, buf, chunk);
88 size -= chunk;
89 offset += chunk;
90 buf += chunk;
91 write_if_needed();
92 }
93 while (size >= BLOCKSIZE) {
94 reliable_write(buf, BLOCKSIZE);
95 size -= BLOCKSIZE;
96 buf += BLOCKSIZE;
97 }
98 if (size) {
99 memcpy(block + offset, buf, size);
100 offset += size;
101 }
102 tail = offset % RECORDSIZE;
103 if (tail) {
104 memset(block + offset, 0, RECORDSIZE - tail);
105 offset += RECORDSIZE - tail;
106 }
107 write_if_needed();
108 }
109
110 static void strbuf_append_string(struct strbuf *sb, const char *s)
111 {
112 int slen = strlen(s);
113 int total = sb->len + slen;
114 if (total > sb->alloc) {
115 sb->buf = xrealloc(sb->buf, total);
116 sb->alloc = total;
117 }
118 memcpy(sb->buf + sb->len, s, slen);
119 sb->len = total;
120 }
121
122 /*
123 * pax extended header records have the format "%u %s=%s\n". %u contains
124 * the size of the whole string (including the %u), the first %s is the
125 * keyword, the second one is the value. This function constructs such a
126 * string and appends it to a struct strbuf.
127 */
128 static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
129 const char *value, unsigned int valuelen)
130 {
131 char *p;
132 int len, total, tmp;
133
134 /* "%u %s=%s\n" */
135 len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
136 for (tmp = len; tmp > 9; tmp /= 10)
137 len++;
138
139 total = sb->len + len;
140 if (total > sb->alloc) {
141 sb->buf = xrealloc(sb->buf, total);
142 sb->alloc = total;
143 }
144
145 p = sb->buf;
146 p += sprintf(p, "%u %s=", len, keyword);
147 memcpy(p, value, valuelen);
148 p += valuelen;
149 *p = '\n';
150 sb->len = total;
151 }
152
153 static unsigned int ustar_header_chksum(const struct ustar_header *header)
154 {
155 char *p = (char *)header;
156 unsigned int chksum = 0;
157 while (p < header->chksum)
158 chksum += *p++;
159 chksum += sizeof(header->chksum) * ' ';
160 p += sizeof(header->chksum);
161 while (p < (char *)header + sizeof(struct ustar_header))
162 chksum += *p++;
163 return chksum;
164 }
165
166 static int get_path_prefix(const struct strbuf *path, int maxlen)
167 {
168 int i = path->len;
169 if (i > maxlen)
170 i = maxlen;
171 while (i > 0 && path->buf[i] != '/')
172 i--;
173 return i;
174 }
175
176 static void write_entry(const unsigned char *sha1, struct strbuf *path,
177 unsigned int mode, void *buffer, unsigned long size)
178 {
179 struct ustar_header header;
180 struct strbuf ext_header;
181
182 memset(&header, 0, sizeof(header));
183 ext_header.buf = NULL;
184 ext_header.len = ext_header.alloc = 0;
185
186 if (!sha1) {
187 *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
188 mode = 0100666;
189 strcpy(header.name, "pax_global_header");
190 } else if (!path) {
191 *header.typeflag = TYPEFLAG_EXT_HEADER;
192 mode = 0100666;
193 sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
194 } else {
195 if (S_ISDIR(mode)) {
196 *header.typeflag = TYPEFLAG_DIR;
197 mode |= 0777;
198 } else if (S_ISLNK(mode)) {
199 *header.typeflag = TYPEFLAG_LNK;
200 mode |= 0777;
201 } else if (S_ISREG(mode)) {
202 *header.typeflag = TYPEFLAG_REG;
203 mode |= (mode & 0100) ? 0777 : 0666;
204 } else {
205 error("unsupported file mode: 0%o (SHA1: %s)",
206 mode, sha1_to_hex(sha1));
207 return;
208 }
209 if (path->len > sizeof(header.name)) {
210 int plen = get_path_prefix(path, sizeof(header.prefix));
211 int rest = path->len - plen - 1;
212 if (plen > 0 && rest <= sizeof(header.name)) {
213 memcpy(header.prefix, path->buf, plen);
214 memcpy(header.name, path->buf + plen + 1, rest);
215 } else {
216 sprintf(header.name, "%s.data",
217 sha1_to_hex(sha1));
218 strbuf_append_ext_header(&ext_header, "path",
219 path->buf, path->len);
220 }
221 } else
222 memcpy(header.name, path->buf, path->len);
223 }
224
225 if (S_ISLNK(mode) && buffer) {
226 if (size > sizeof(header.linkname)) {
227 sprintf(header.linkname, "see %s.paxheader",
228 sha1_to_hex(sha1));
229 strbuf_append_ext_header(&ext_header, "linkpath",
230 buffer, size);
231 } else
232 memcpy(header.linkname, buffer, size);
233 }
234
235 sprintf(header.mode, "%07o", mode & 07777);
236 sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
237 sprintf(header.mtime, "%011lo", archive_time);
238
239 /* XXX: should we provide more meaningful info here? */
240 sprintf(header.uid, "%07o", 0);
241 sprintf(header.gid, "%07o", 0);
242 strncpy(header.uname, "git", 31);
243 strncpy(header.gname, "git", 31);
244 sprintf(header.devmajor, "%07o", 0);
245 sprintf(header.devminor, "%07o", 0);
246
247 memcpy(header.magic, "ustar", 6);
248 memcpy(header.version, "00", 2);
249
250 sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
251
252 if (ext_header.len > 0) {
253 write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
254 free(ext_header.buf);
255 }
256 write_blocked(&header, sizeof(header));
257 if (S_ISREG(mode) && buffer && size > 0)
258 write_blocked(buffer, size);
259 }
260
261 static void write_global_extended_header(const unsigned char *sha1)
262 {
263 struct strbuf ext_header;
264 ext_header.buf = NULL;
265 ext_header.len = ext_header.alloc = 0;
266 strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
267 write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
268 free(ext_header.buf);
269 }
270
271 static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
272 {
273 int pathlen = path->len;
274 struct name_entry entry;
275
276 while (tree_entry(tree, &entry)) {
277 void *eltbuf;
278 char elttype[20];
279 unsigned long eltsize;
280
281 eltbuf = read_sha1_file(entry.sha1, elttype, &eltsize);
282 if (!eltbuf)
283 die("cannot read %s", sha1_to_hex(entry.sha1));
284
285 path->len = pathlen;
286 strbuf_append_string(path, entry.path);
287 if (S_ISDIR(entry.mode))
288 strbuf_append_string(path, "/");
289
290 write_entry(entry.sha1, path, entry.mode, eltbuf, eltsize);
291
292 if (S_ISDIR(entry.mode)) {
293 struct tree_desc subtree;
294 subtree.buf = eltbuf;
295 subtree.size = eltsize;
296 traverse_tree(&subtree, path);
297 }
298 free(eltbuf);
299 }
300 }
301
302 static int generate_tar(int argc, const char **argv, char** envp)
303 {
304 unsigned char sha1[20], tree_sha1[20];
305 struct commit *commit;
306 struct tree_desc tree;
307 struct strbuf current_path;
308
309 current_path.buf = xmalloc(PATH_MAX);
310 current_path.alloc = PATH_MAX;
311 current_path.len = current_path.eof = 0;
312
313 setup_git_directory();
314 git_config(git_default_config);
315
316 switch (argc) {
317 case 3:
318 strbuf_append_string(&current_path, argv[2]);
319 strbuf_append_string(&current_path, "/");
320 /* FALLTHROUGH */
321 case 2:
322 if (get_sha1(argv[1], sha1))
323 die("Not a valid object name %s", argv[1]);
324 break;
325 default:
326 usage(tar_tree_usage);
327 }
328
329 commit = lookup_commit_reference_gently(sha1, 1);
330 if (commit) {
331 write_global_extended_header(commit->object.sha1);
332 archive_time = commit->date;
333 } else
334 archive_time = time(NULL);
335
336 tree.buf = read_object_with_reference(sha1, tree_type, &tree.size,
337 tree_sha1);
338 if (!tree.buf)
339 die("not a reference to a tag, commit or tree object: %s",
340 sha1_to_hex(sha1));
341
342 if (current_path.len > 0)
343 write_entry(tree_sha1, &current_path, 040777, NULL, 0);
344 traverse_tree(&tree, &current_path);
345 write_trailer();
346 free(current_path.buf);
347 return 0;
348 }
349
350 static const char *exec = "git-upload-tar";
351
352 static int remote_tar(int argc, const char **argv)
353 {
354 int fd[2], ret, len;
355 pid_t pid;
356 char buf[1024];
357 char *url;
358
359 if (argc < 3 || 4 < argc)
360 usage(tar_tree_usage);
361
362 /* --remote=<repo> */
363 url = strdup(argv[1]+9);
364 pid = git_connect(fd, url, exec);
365 if (pid < 0)
366 return 1;
367
368 packet_write(fd[1], "want %s\n", argv[2]);
369 if (argv[3])
370 packet_write(fd[1], "base %s\n", argv[3]);
371 packet_flush(fd[1]);
372
373 len = packet_read_line(fd[0], buf, sizeof(buf));
374 if (!len)
375 die("git-tar-tree: expected ACK/NAK, got EOF");
376 if (buf[len-1] == '\n')
377 buf[--len] = 0;
378 if (strcmp(buf, "ACK")) {
379 if (5 < len && !strncmp(buf, "NACK ", 5))
380 die("git-tar-tree: NACK %s", buf + 5);
381 die("git-tar-tree: protocol error");
382 }
383 /* expect a flush */
384 len = packet_read_line(fd[0], buf, sizeof(buf));
385 if (len)
386 die("git-tar-tree: expected a flush");
387
388 /* Now, start reading from fd[0] and spit it out to stdout */
389 ret = copy_fd(fd[0], 1);
390 close(fd[0]);
391
392 ret |= finish_connect(pid);
393 return !!ret;
394 }
395
396 int cmd_tar_tree(int argc, const char **argv, char **envp)
397 {
398 if (argc < 2)
399 usage(tar_tree_usage);
400 if (!strncmp("--remote=", argv[1], 9))
401 return remote_tar(argc, argv);
402 return generate_tar(argc, argv, envp);
403 }