Merge branch 'jb/am-include'
[git] / archive-tar.c
1 /*
2  * Copyright (c) 2005, 2006 Rene Scharfe
3  */
4 #include "cache.h"
5 #include "tar.h"
6 #include "archive.h"
7 #include "run-command.h"
8
9 #define RECORDSIZE      (512)
10 #define BLOCKSIZE       (RECORDSIZE * 20)
11
12 static char block[BLOCKSIZE];
13 static unsigned long offset;
14
15 static int tar_umask = 002;
16
17 static int write_tar_filter_archive(const struct archiver *ar,
18                                     struct archiver_args *args);
19
20 /* writes out the whole block, but only if it is full */
21 static void write_if_needed(void)
22 {
23         if (offset == BLOCKSIZE) {
24                 write_or_die(1, block, BLOCKSIZE);
25                 offset = 0;
26         }
27 }
28
29 /*
30  * queues up writes, so that all our write(2) calls write exactly one
31  * full block; pads writes to RECORDSIZE
32  */
33 static void write_blocked(const void *data, unsigned long size)
34 {
35         const char *buf = data;
36         unsigned long tail;
37
38         if (offset) {
39                 unsigned long chunk = BLOCKSIZE - offset;
40                 if (size < chunk)
41                         chunk = size;
42                 memcpy(block + offset, buf, chunk);
43                 size -= chunk;
44                 offset += chunk;
45                 buf += chunk;
46                 write_if_needed();
47         }
48         while (size >= BLOCKSIZE) {
49                 write_or_die(1, buf, BLOCKSIZE);
50                 size -= BLOCKSIZE;
51                 buf += BLOCKSIZE;
52         }
53         if (size) {
54                 memcpy(block + offset, buf, size);
55                 offset += size;
56         }
57         tail = offset % RECORDSIZE;
58         if (tail)  {
59                 memset(block + offset, 0, RECORDSIZE - tail);
60                 offset += RECORDSIZE - tail;
61         }
62         write_if_needed();
63 }
64
65 /*
66  * The end of tar archives is marked by 2*512 nul bytes and after that
67  * follows the rest of the block (if any).
68  */
69 static void write_trailer(void)
70 {
71         int tail = BLOCKSIZE - offset;
72         memset(block + offset, 0, tail);
73         write_or_die(1, block, BLOCKSIZE);
74         if (tail < 2 * RECORDSIZE) {
75                 memset(block, 0, offset);
76                 write_or_die(1, block, BLOCKSIZE);
77         }
78 }
79
80 /*
81  * pax extended header records have the format "%u %s=%s\n".  %u contains
82  * the size of the whole string (including the %u), the first %s is the
83  * keyword, the second one is the value.  This function constructs such a
84  * string and appends it to a struct strbuf.
85  */
86 static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
87                                      const char *value, unsigned int valuelen)
88 {
89         int len, tmp;
90
91         /* "%u %s=%s\n" */
92         len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
93         for (tmp = len; tmp > 9; tmp /= 10)
94                 len++;
95
96         strbuf_grow(sb, len);
97         strbuf_addf(sb, "%u %s=", len, keyword);
98         strbuf_add(sb, value, valuelen);
99         strbuf_addch(sb, '\n');
100 }
101
102 static unsigned int ustar_header_chksum(const struct ustar_header *header)
103 {
104         char *p = (char *)header;
105         unsigned int chksum = 0;
106         while (p < header->chksum)
107                 chksum += *p++;
108         chksum += sizeof(header->chksum) * ' ';
109         p += sizeof(header->chksum);
110         while (p < (char *)header + sizeof(struct ustar_header))
111                 chksum += *p++;
112         return chksum;
113 }
114
115 static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
116 {
117         size_t i = pathlen;
118         if (i > maxlen)
119                 i = maxlen;
120         do {
121                 i--;
122         } while (i > 0 && path[i] != '/');
123         return i;
124 }
125
126 static int write_tar_entry(struct archiver_args *args,
127                 const unsigned char *sha1, const char *path, size_t pathlen,
128                 unsigned int mode, void *buffer, unsigned long size)
129 {
130         struct ustar_header header;
131         struct strbuf ext_header = STRBUF_INIT;
132         int err = 0;
133
134         memset(&header, 0, sizeof(header));
135
136         if (!sha1) {
137                 *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
138                 mode = 0100666;
139                 strcpy(header.name, "pax_global_header");
140         } else if (!path) {
141                 *header.typeflag = TYPEFLAG_EXT_HEADER;
142                 mode = 0100666;
143                 sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
144         } else {
145                 if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
146                         *header.typeflag = TYPEFLAG_DIR;
147                         mode = (mode | 0777) & ~tar_umask;
148                 } else if (S_ISLNK(mode)) {
149                         *header.typeflag = TYPEFLAG_LNK;
150                         mode |= 0777;
151                 } else if (S_ISREG(mode)) {
152                         *header.typeflag = TYPEFLAG_REG;
153                         mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
154                 } else {
155                         return error("unsupported file mode: 0%o (SHA1: %s)",
156                                         mode, sha1_to_hex(sha1));
157                 }
158                 if (pathlen > sizeof(header.name)) {
159                         size_t plen = get_path_prefix(path, pathlen,
160                                         sizeof(header.prefix));
161                         size_t rest = pathlen - plen - 1;
162                         if (plen > 0 && rest <= sizeof(header.name)) {
163                                 memcpy(header.prefix, path, plen);
164                                 memcpy(header.name, path + plen + 1, rest);
165                         } else {
166                                 sprintf(header.name, "%s.data",
167                                         sha1_to_hex(sha1));
168                                 strbuf_append_ext_header(&ext_header, "path",
169                                                 path, pathlen);
170                         }
171                 } else
172                         memcpy(header.name, path, pathlen);
173         }
174
175         if (S_ISLNK(mode) && buffer) {
176                 if (size > sizeof(header.linkname)) {
177                         sprintf(header.linkname, "see %s.paxheader",
178                                 sha1_to_hex(sha1));
179                         strbuf_append_ext_header(&ext_header, "linkpath",
180                                                  buffer, size);
181                 } else
182                         memcpy(header.linkname, buffer, size);
183         }
184
185         sprintf(header.mode, "%07o", mode & 07777);
186         sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
187         sprintf(header.mtime, "%011lo", (unsigned long) args->time);
188
189         sprintf(header.uid, "%07o", 0);
190         sprintf(header.gid, "%07o", 0);
191         strlcpy(header.uname, "root", sizeof(header.uname));
192         strlcpy(header.gname, "root", sizeof(header.gname));
193         sprintf(header.devmajor, "%07o", 0);
194         sprintf(header.devminor, "%07o", 0);
195
196         memcpy(header.magic, "ustar", 6);
197         memcpy(header.version, "00", 2);
198
199         sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
200
201         if (ext_header.len > 0) {
202                 err = write_tar_entry(args, sha1, NULL, 0, 0, ext_header.buf,
203                                 ext_header.len);
204                 if (err)
205                         return err;
206         }
207         strbuf_release(&ext_header);
208         write_blocked(&header, sizeof(header));
209         if (S_ISREG(mode) && buffer && size > 0)
210                 write_blocked(buffer, size);
211         return err;
212 }
213
214 static int write_global_extended_header(struct archiver_args *args)
215 {
216         const unsigned char *sha1 = args->commit_sha1;
217         struct strbuf ext_header = STRBUF_INIT;
218         int err;
219
220         strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
221         err = write_tar_entry(args, NULL, NULL, 0, 0, ext_header.buf,
222                         ext_header.len);
223         strbuf_release(&ext_header);
224         return err;
225 }
226
227 static struct archiver **tar_filters;
228 static int nr_tar_filters;
229 static int alloc_tar_filters;
230
231 static struct archiver *find_tar_filter(const char *name, int len)
232 {
233         int i;
234         for (i = 0; i < nr_tar_filters; i++) {
235                 struct archiver *ar = tar_filters[i];
236                 if (!strncmp(ar->name, name, len) && !ar->name[len])
237                         return ar;
238         }
239         return NULL;
240 }
241
242 static int tar_filter_config(const char *var, const char *value, void *data)
243 {
244         struct archiver *ar;
245         const char *dot;
246         const char *name;
247         const char *type;
248         int namelen;
249
250         if (prefixcmp(var, "tar."))
251                 return 0;
252         dot = strrchr(var, '.');
253         if (dot == var + 9)
254                 return 0;
255
256         name = var + 4;
257         namelen = dot - name;
258         type = dot + 1;
259
260         ar = find_tar_filter(name, namelen);
261         if (!ar) {
262                 ar = xcalloc(1, sizeof(*ar));
263                 ar->name = xmemdupz(name, namelen);
264                 ar->write_archive = write_tar_filter_archive;
265                 ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
266                 ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
267                 tar_filters[nr_tar_filters++] = ar;
268         }
269
270         if (!strcmp(type, "command")) {
271                 if (!value)
272                         return config_error_nonbool(var);
273                 free(ar->data);
274                 ar->data = xstrdup(value);
275                 return 0;
276         }
277         if (!strcmp(type, "remote")) {
278                 if (git_config_bool(var, value))
279                         ar->flags |= ARCHIVER_REMOTE;
280                 else
281                         ar->flags &= ~ARCHIVER_REMOTE;
282                 return 0;
283         }
284
285         return 0;
286 }
287
288 static int git_tar_config(const char *var, const char *value, void *cb)
289 {
290         if (!strcmp(var, "tar.umask")) {
291                 if (value && !strcmp(value, "user")) {
292                         tar_umask = umask(0);
293                         umask(tar_umask);
294                 } else {
295                         tar_umask = git_config_int(var, value);
296                 }
297                 return 0;
298         }
299
300         return tar_filter_config(var, value, cb);
301 }
302
303 static int write_tar_archive(const struct archiver *ar,
304                              struct archiver_args *args)
305 {
306         int err = 0;
307
308         if (args->commit_sha1)
309                 err = write_global_extended_header(args);
310         if (!err)
311                 err = write_archive_entries(args, write_tar_entry);
312         if (!err)
313                 write_trailer();
314         return err;
315 }
316
317 static int write_tar_filter_archive(const struct archiver *ar,
318                                     struct archiver_args *args)
319 {
320         struct strbuf cmd = STRBUF_INIT;
321         struct child_process filter;
322         const char *argv[2];
323         int r;
324
325         if (!ar->data)
326                 die("BUG: tar-filter archiver called with no filter defined");
327
328         strbuf_addstr(&cmd, ar->data);
329         if (args->compression_level >= 0)
330                 strbuf_addf(&cmd, " -%d", args->compression_level);
331
332         memset(&filter, 0, sizeof(filter));
333         argv[0] = cmd.buf;
334         argv[1] = NULL;
335         filter.argv = argv;
336         filter.use_shell = 1;
337         filter.in = -1;
338
339         if (start_command(&filter) < 0)
340                 die_errno("unable to start '%s' filter", argv[0]);
341         close(1);
342         if (dup2(filter.in, 1) < 0)
343                 die_errno("unable to redirect descriptor");
344         close(filter.in);
345
346         r = write_tar_archive(ar, args);
347
348         close(1);
349         if (finish_command(&filter) != 0)
350                 die("'%s' filter reported error", argv[0]);
351
352         strbuf_release(&cmd);
353         return r;
354 }
355
356 static struct archiver tar_archiver = {
357         "tar",
358         write_tar_archive,
359         ARCHIVER_REMOTE
360 };
361
362 void init_tar_archiver(void)
363 {
364         int i;
365         register_archiver(&tar_archiver);
366
367         tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
368         tar_filter_config("tar.tgz.remote", "true", NULL);
369         tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
370         tar_filter_config("tar.tar.gz.remote", "true", NULL);
371         git_config(git_tar_config, NULL);
372         for (i = 0; i < nr_tar_filters; i++) {
373                 /* omit any filters that never had a command configured */
374                 if (tar_filters[i]->data)
375                         register_archiver(tar_filters[i]);
376         }
377 }