2 * Copyright (c) 2005, 2006 Rene Scharfe
11 #define RECORDSIZE (512)
12 #define BLOCKSIZE (RECORDSIZE * 20)
14 static const char tar_tree_usage
[] = "git-tar-tree <key> [basedir]";
16 static char block
[BLOCKSIZE
];
17 static unsigned long offset
;
19 static time_t archive_time
;
21 /* tries hard to write, either succeeds or dies in the attempt */
22 static void reliable_write(void *buf
, unsigned long size
)
25 long ret
= xwrite(1, buf
, size
);
29 die("git-tar-tree: %s", strerror(errno
));
31 die("git-tar-tree: disk full?");
38 /* writes out the whole block, but only if it is full */
39 static void write_if_needed(void)
41 if (offset
== BLOCKSIZE
) {
42 reliable_write(block
, BLOCKSIZE
);
47 /* acquire the next record from the buffer; user must call write_if_needed() */
48 static char *get_record(void)
50 char *p
= block
+ offset
;
51 memset(p
, 0, RECORDSIZE
);
57 * The end of tar archives is marked by 1024 nul bytes and after that
58 * follows the rest of the block (if any).
60 static void write_trailer(void)
73 * queues up writes, so that all our write(2) calls write exactly one
74 * full block; pads writes to RECORDSIZE
76 static void write_blocked(void *buf
, unsigned long size
)
81 unsigned long chunk
= BLOCKSIZE
- offset
;
84 memcpy(block
+ offset
, buf
, chunk
);
90 while (size
>= BLOCKSIZE
) {
91 reliable_write(buf
, BLOCKSIZE
);
96 memcpy(block
+ offset
, buf
, size
);
100 tail
= offset
% RECORDSIZE
;
102 memset(block
+ offset
, 0, RECORDSIZE
- tail
);
103 offset
+= RECORDSIZE
- tail
;
108 static void strbuf_append_string(struct strbuf
*sb
, const char *s
)
110 int slen
= strlen(s
);
111 int total
= sb
->len
+ slen
;
112 if (total
> sb
->alloc
) {
113 sb
->buf
= xrealloc(sb
->buf
, total
);
116 memcpy(sb
->buf
+ sb
->len
, s
, slen
);
121 * pax extended header records have the format "%u %s=%s\n". %u contains
122 * the size of the whole string (including the %u), the first %s is the
123 * keyword, the second one is the value. This function constructs such a
124 * string and appends it to a struct strbuf.
126 static void strbuf_append_ext_header(struct strbuf
*sb
, const char *keyword
,
127 const char *value
, unsigned int valuelen
)
133 len
= 1 + 1 + strlen(keyword
) + 1 + valuelen
+ 1;
134 for (tmp
= len
; tmp
> 9; tmp
/= 10)
137 total
= sb
->len
+ len
;
138 if (total
> sb
->alloc
) {
139 sb
->buf
= xrealloc(sb
->buf
, total
);
144 p
+= sprintf(p
, "%u %s=", len
, keyword
);
145 memcpy(p
, value
, valuelen
);
151 static unsigned int ustar_header_chksum(const struct ustar_header
*header
)
153 char *p
= (char *)header
;
154 unsigned int chksum
= 0;
155 while (p
< header
->chksum
)
157 chksum
+= sizeof(header
->chksum
) * ' ';
158 p
+= sizeof(header
->chksum
);
159 while (p
< (char *)header
+ sizeof(struct ustar_header
))
164 static int get_path_prefix(const struct strbuf
*path
, int maxlen
)
169 while (i
> 0 && path
->buf
[i
] != '/')
174 static void write_entry(const unsigned char *sha1
, struct strbuf
*path
,
175 unsigned int mode
, void *buffer
, unsigned long size
)
177 struct ustar_header header
;
178 struct strbuf ext_header
;
180 memset(&header
, 0, sizeof(header
));
181 ext_header
.buf
= NULL
;
182 ext_header
.len
= ext_header
.alloc
= 0;
185 *header
.typeflag
= TYPEFLAG_GLOBAL_HEADER
;
187 strcpy(header
.name
, "pax_global_header");
189 *header
.typeflag
= TYPEFLAG_EXT_HEADER
;
191 sprintf(header
.name
, "%s.paxheader", sha1_to_hex(sha1
));
194 *header
.typeflag
= TYPEFLAG_DIR
;
196 } else if (S_ISLNK(mode
)) {
197 *header
.typeflag
= TYPEFLAG_LNK
;
199 } else if (S_ISREG(mode
)) {
200 *header
.typeflag
= TYPEFLAG_REG
;
201 mode
|= (mode
& 0100) ? 0777 : 0666;
203 error("unsupported file mode: 0%o (SHA1: %s)",
204 mode
, sha1_to_hex(sha1
));
207 if (path
->len
> sizeof(header
.name
)) {
208 int plen
= get_path_prefix(path
, sizeof(header
.prefix
));
209 int rest
= path
->len
- plen
- 1;
210 if (plen
> 0 && rest
<= sizeof(header
.name
)) {
211 memcpy(header
.prefix
, path
->buf
, plen
);
212 memcpy(header
.name
, path
->buf
+ plen
+ 1, rest
);
214 sprintf(header
.name
, "%s.data",
216 strbuf_append_ext_header(&ext_header
, "path",
217 path
->buf
, path
->len
);
220 memcpy(header
.name
, path
->buf
, path
->len
);
223 if (S_ISLNK(mode
) && buffer
) {
224 if (size
> sizeof(header
.linkname
)) {
225 sprintf(header
.linkname
, "see %s.paxheader",
227 strbuf_append_ext_header(&ext_header
, "linkpath",
230 memcpy(header
.linkname
, buffer
, size
);
233 sprintf(header
.mode
, "%07o", mode
& 07777);
234 sprintf(header
.size
, "%011lo", S_ISREG(mode
) ? size
: 0);
235 sprintf(header
.mtime
, "%011lo", archive_time
);
237 /* XXX: should we provide more meaningful info here? */
238 sprintf(header
.uid
, "%07o", 0);
239 sprintf(header
.gid
, "%07o", 0);
240 strncpy(header
.uname
, "git", 31);
241 strncpy(header
.gname
, "git", 31);
242 sprintf(header
.devmajor
, "%07o", 0);
243 sprintf(header
.devminor
, "%07o", 0);
245 memcpy(header
.magic
, "ustar", 6);
246 memcpy(header
.version
, "00", 2);
248 sprintf(header
.chksum
, "%07o", ustar_header_chksum(&header
));
250 if (ext_header
.len
> 0) {
251 write_entry(sha1
, NULL
, 0, ext_header
.buf
, ext_header
.len
);
252 free(ext_header
.buf
);
254 write_blocked(&header
, sizeof(header
));
255 if (S_ISREG(mode
) && buffer
&& size
> 0)
256 write_blocked(buffer
, size
);
259 static void write_global_extended_header(const unsigned char *sha1
)
261 struct strbuf ext_header
;
262 ext_header
.buf
= NULL
;
263 ext_header
.len
= ext_header
.alloc
= 0;
264 strbuf_append_ext_header(&ext_header
, "comment", sha1_to_hex(sha1
), 40);
265 write_entry(NULL
, NULL
, 0, ext_header
.buf
, ext_header
.len
);
266 free(ext_header
.buf
);
269 static void traverse_tree(struct tree_desc
*tree
, struct strbuf
*path
)
271 int pathlen
= path
->len
;
275 const unsigned char *sha1
;
279 unsigned long eltsize
;
281 sha1
= tree_entry_extract(tree
, &name
, &mode
);
282 update_tree_entry(tree
);
284 eltbuf
= read_sha1_file(sha1
, elttype
, &eltsize
);
286 die("cannot read %s", sha1_to_hex(sha1
));
289 strbuf_append_string(path
, name
);
291 strbuf_append_string(path
, "/");
293 write_entry(sha1
, path
, mode
, eltbuf
, eltsize
);
296 struct tree_desc subtree
;
297 subtree
.buf
= eltbuf
;
298 subtree
.size
= eltsize
;
299 traverse_tree(&subtree
, path
);
305 int main(int argc
, char **argv
)
307 unsigned char sha1
[20], tree_sha1
[20];
308 struct commit
*commit
;
309 struct tree_desc tree
;
310 struct strbuf current_path
;
312 current_path
.buf
= xmalloc(PATH_MAX
);
313 current_path
.alloc
= PATH_MAX
;
314 current_path
.len
= current_path
.eof
= 0;
316 setup_git_directory();
320 strbuf_append_string(¤t_path
, argv
[2]);
321 strbuf_append_string(¤t_path
, "/");
324 if (get_sha1(argv
[1], sha1
) < 0)
325 usage(tar_tree_usage
);
328 usage(tar_tree_usage
);
331 commit
= lookup_commit_reference_gently(sha1
, 1);
333 write_global_extended_header(commit
->object
.sha1
);
334 archive_time
= commit
->date
;
336 archive_time
= time(NULL
);
338 tree
.buf
= read_object_with_reference(sha1
, "tree", &tree
.size
,
341 die("not a reference to a tag, commit or tree object: %s",
344 if (current_path
.len
> 0)
345 write_entry(tree_sha1
, ¤t_path
, 040777, NULL
, 0);
346 traverse_tree(&tree
, ¤t_path
);
348 free(current_path
.buf
);