git-name-rev.txt: document --no-undefined and --always
[git] / archive-tar.c
1 /*
2  * Copyright (c) 2005, 2006 Rene Scharfe
3  */
4 #include "cache.h"
5 #include "commit.h"
6 #include "tar.h"
7 #include "builtin.h"
8 #include "archive.h"
9
10 #define RECORDSIZE      (512)
11 #define BLOCKSIZE       (RECORDSIZE * 20)
12
13 static char block[BLOCKSIZE];
14 static unsigned long offset;
15
16 static time_t archive_time;
17 static int tar_umask = 002;
18 static int verbose;
19 static const struct commit *commit;
20 static size_t base_len;
21
22 /* writes out the whole block, but only if it is full */
23 static void write_if_needed(void)
24 {
25         if (offset == BLOCKSIZE) {
26                 write_or_die(1, block, BLOCKSIZE);
27                 offset = 0;
28         }
29 }
30
31 /*
32  * queues up writes, so that all our write(2) calls write exactly one
33  * full block; pads writes to RECORDSIZE
34  */
35 static void write_blocked(const void *data, unsigned long size)
36 {
37         const char *buf = data;
38         unsigned long tail;
39
40         if (offset) {
41                 unsigned long chunk = BLOCKSIZE - offset;
42                 if (size < chunk)
43                         chunk = size;
44                 memcpy(block + offset, buf, chunk);
45                 size -= chunk;
46                 offset += chunk;
47                 buf += chunk;
48                 write_if_needed();
49         }
50         while (size >= BLOCKSIZE) {
51                 write_or_die(1, buf, BLOCKSIZE);
52                 size -= BLOCKSIZE;
53                 buf += BLOCKSIZE;
54         }
55         if (size) {
56                 memcpy(block + offset, buf, size);
57                 offset += size;
58         }
59         tail = offset % RECORDSIZE;
60         if (tail)  {
61                 memset(block + offset, 0, RECORDSIZE - tail);
62                 offset += RECORDSIZE - tail;
63         }
64         write_if_needed();
65 }
66
67 /*
68  * The end of tar archives is marked by 2*512 nul bytes and after that
69  * follows the rest of the block (if any).
70  */
71 static void write_trailer(void)
72 {
73         int tail = BLOCKSIZE - offset;
74         memset(block + offset, 0, tail);
75         write_or_die(1, block, BLOCKSIZE);
76         if (tail < 2 * RECORDSIZE) {
77                 memset(block, 0, offset);
78                 write_or_die(1, block, BLOCKSIZE);
79         }
80 }
81
82 /*
83  * pax extended header records have the format "%u %s=%s\n".  %u contains
84  * the size of the whole string (including the %u), the first %s is the
85  * keyword, the second one is the value.  This function constructs such a
86  * string and appends it to a struct strbuf.
87  */
88 static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
89                                      const char *value, unsigned int valuelen)
90 {
91         int len, tmp;
92
93         /* "%u %s=%s\n" */
94         len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
95         for (tmp = len; tmp > 9; tmp /= 10)
96                 len++;
97
98         strbuf_grow(sb, len);
99         strbuf_addf(sb, "%u %s=", len, keyword);
100         strbuf_add(sb, value, valuelen);
101         strbuf_addch(sb, '\n');
102 }
103
104 static unsigned int ustar_header_chksum(const struct ustar_header *header)
105 {
106         char *p = (char *)header;
107         unsigned int chksum = 0;
108         while (p < header->chksum)
109                 chksum += *p++;
110         chksum += sizeof(header->chksum) * ' ';
111         p += sizeof(header->chksum);
112         while (p < (char *)header + sizeof(struct ustar_header))
113                 chksum += *p++;
114         return chksum;
115 }
116
117 static int get_path_prefix(const struct strbuf *path, int maxlen)
118 {
119         int i = path->len;
120         if (i > maxlen)
121                 i = maxlen;
122         do {
123                 i--;
124         } while (i > 0 && path->buf[i] != '/');
125         return i;
126 }
127
128 static void write_entry(const unsigned char *sha1, struct strbuf *path,
129                         unsigned int mode, void *buffer, unsigned long size)
130 {
131         struct ustar_header header;
132         struct strbuf ext_header;
133
134         memset(&header, 0, sizeof(header));
135         strbuf_init(&ext_header, 0);
136
137         if (!sha1) {
138                 *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
139                 mode = 0100666;
140                 strcpy(header.name, "pax_global_header");
141         } else if (!path) {
142                 *header.typeflag = TYPEFLAG_EXT_HEADER;
143                 mode = 0100666;
144                 sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
145         } else {
146                 if (verbose)
147                         fprintf(stderr, "%.*s\n", (int)path->len, path->buf);
148                 if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
149                         *header.typeflag = TYPEFLAG_DIR;
150                         mode = (mode | 0777) & ~tar_umask;
151                 } else if (S_ISLNK(mode)) {
152                         *header.typeflag = TYPEFLAG_LNK;
153                         mode |= 0777;
154                 } else if (S_ISREG(mode)) {
155                         *header.typeflag = TYPEFLAG_REG;
156                         mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
157                 } else {
158                         error("unsupported file mode: 0%o (SHA1: %s)",
159                               mode, sha1_to_hex(sha1));
160                         return;
161                 }
162                 if (path->len > sizeof(header.name)) {
163                         int plen = get_path_prefix(path, sizeof(header.prefix));
164                         int rest = path->len - plen - 1;
165                         if (plen > 0 && rest <= sizeof(header.name)) {
166                                 memcpy(header.prefix, path->buf, plen);
167                                 memcpy(header.name, path->buf + plen + 1, rest);
168                         } else {
169                                 sprintf(header.name, "%s.data",
170                                         sha1_to_hex(sha1));
171                                 strbuf_append_ext_header(&ext_header, "path",
172                                                          path->buf, path->len);
173                         }
174                 } else
175                         memcpy(header.name, path->buf, path->len);
176         }
177
178         if (S_ISLNK(mode) && buffer) {
179                 if (size > sizeof(header.linkname)) {
180                         sprintf(header.linkname, "see %s.paxheader",
181                                 sha1_to_hex(sha1));
182                         strbuf_append_ext_header(&ext_header, "linkpath",
183                                                  buffer, size);
184                 } else
185                         memcpy(header.linkname, buffer, size);
186         }
187
188         sprintf(header.mode, "%07o", mode & 07777);
189         sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
190         sprintf(header.mtime, "%011lo", archive_time);
191
192         sprintf(header.uid, "%07o", 0);
193         sprintf(header.gid, "%07o", 0);
194         strlcpy(header.uname, "root", sizeof(header.uname));
195         strlcpy(header.gname, "root", sizeof(header.gname));
196         sprintf(header.devmajor, "%07o", 0);
197         sprintf(header.devminor, "%07o", 0);
198
199         memcpy(header.magic, "ustar", 6);
200         memcpy(header.version, "00", 2);
201
202         sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
203
204         if (ext_header.len > 0) {
205                 write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
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 }
212
213 static void write_global_extended_header(const unsigned char *sha1)
214 {
215         struct strbuf ext_header;
216
217         strbuf_init(&ext_header, 0);
218         strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
219         write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
220         strbuf_release(&ext_header);
221 }
222
223 static int git_tar_config(const char *var, const char *value, void *cb)
224 {
225         if (!strcmp(var, "tar.umask")) {
226                 if (value && !strcmp(value, "user")) {
227                         tar_umask = umask(0);
228                         umask(tar_umask);
229                 } else {
230                         tar_umask = git_config_int(var, value);
231                 }
232                 return 0;
233         }
234         return git_default_config(var, value, cb);
235 }
236
237 static int write_tar_entry(const unsigned char *sha1,
238                            const char *base, int baselen,
239                            const char *filename, unsigned mode, int stage)
240 {
241         static struct strbuf path = STRBUF_INIT;
242         void *buffer;
243         enum object_type type;
244         unsigned long size;
245
246         strbuf_reset(&path);
247         strbuf_grow(&path, PATH_MAX);
248         strbuf_add(&path, base, baselen);
249         strbuf_addstr(&path, filename);
250         if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
251                 strbuf_addch(&path, '/');
252                 buffer = NULL;
253                 size = 0;
254         } else {
255                 buffer = sha1_file_to_archive(path.buf + base_len, sha1, mode,
256                                 &type, &size, commit);
257                 if (!buffer)
258                         die("cannot read %s", sha1_to_hex(sha1));
259         }
260
261         write_entry(sha1, &path, mode, buffer, size);
262         free(buffer);
263
264         return READ_TREE_RECURSIVE;
265 }
266
267 int write_tar_archive(struct archiver_args *args)
268 {
269         int plen = args->base ? strlen(args->base) : 0;
270
271         git_config(git_tar_config, NULL);
272
273         archive_time = args->time;
274         verbose = args->verbose;
275         commit = args->commit;
276         base_len = args->base ? strlen(args->base) : 0;
277
278         if (args->commit_sha1)
279                 write_global_extended_header(args->commit_sha1);
280
281         if (args->base && plen > 0 && args->base[plen - 1] == '/') {
282                 char *base = xstrdup(args->base);
283                 int baselen = strlen(base);
284
285                 while (baselen > 0 && base[baselen - 1] == '/')
286                         base[--baselen] = '\0';
287                 write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
288                 free(base);
289         }
290         read_tree_recursive(args->tree, args->base, plen, 0,
291                             args->pathspec, write_tar_entry);
292         write_trailer();
293
294         return 0;
295 }