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[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
21 /* writes out the whole block, but only if it is full */
22 static void write_if_needed(void)
23 {
24         if (offset == BLOCKSIZE) {
25                 write_or_die(1, block, BLOCKSIZE);
26                 offset = 0;
27         }
28 }
29
30 /*
31  * queues up writes, so that all our write(2) calls write exactly one
32  * full block; pads writes to RECORDSIZE
33  */
34 static void write_blocked(const void *data, unsigned long size)
35 {
36         const char *buf = data;
37         unsigned long tail;
38
39         if (offset) {
40                 unsigned long chunk = BLOCKSIZE - offset;
41                 if (size < chunk)
42                         chunk = size;
43                 memcpy(block + offset, buf, chunk);
44                 size -= chunk;
45                 offset += chunk;
46                 buf += chunk;
47                 write_if_needed();
48         }
49         while (size >= BLOCKSIZE) {
50                 write_or_die(1, buf, BLOCKSIZE);
51                 size -= BLOCKSIZE;
52                 buf += BLOCKSIZE;
53         }
54         if (size) {
55                 memcpy(block + offset, buf, size);
56                 offset += size;
57         }
58         tail = offset % RECORDSIZE;
59         if (tail)  {
60                 memset(block + offset, 0, RECORDSIZE - tail);
61                 offset += RECORDSIZE - tail;
62         }
63         write_if_needed();
64 }
65
66 /*
67  * The end of tar archives is marked by 2*512 nul bytes and after that
68  * follows the rest of the block (if any).
69  */
70 static void write_trailer(void)
71 {
72         int tail = BLOCKSIZE - offset;
73         memset(block + offset, 0, tail);
74         write_or_die(1, block, BLOCKSIZE);
75         if (tail < 2 * RECORDSIZE) {
76                 memset(block, 0, offset);
77                 write_or_die(1, block, BLOCKSIZE);
78         }
79 }
80
81 /*
82  * pax extended header records have the format "%u %s=%s\n".  %u contains
83  * the size of the whole string (including the %u), the first %s is the
84  * keyword, the second one is the value.  This function constructs such a
85  * string and appends it to a struct strbuf.
86  */
87 static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
88                                      const char *value, unsigned int valuelen)
89 {
90         int len, tmp;
91
92         /* "%u %s=%s\n" */
93         len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
94         for (tmp = len; tmp > 9; tmp /= 10)
95                 len++;
96
97         strbuf_grow(sb, len);
98         strbuf_addf(sb, "%u %s=", len, keyword);
99         strbuf_add(sb, value, valuelen);
100         strbuf_addch(sb, '\n');
101 }
102
103 static unsigned int ustar_header_chksum(const struct ustar_header *header)
104 {
105         char *p = (char *)header;
106         unsigned int chksum = 0;
107         while (p < header->chksum)
108                 chksum += *p++;
109         chksum += sizeof(header->chksum) * ' ';
110         p += sizeof(header->chksum);
111         while (p < (char *)header + sizeof(struct ustar_header))
112                 chksum += *p++;
113         return chksum;
114 }
115
116 static int get_path_prefix(const struct strbuf *path, int maxlen)
117 {
118         int i = path->len;
119         if (i > maxlen)
120                 i = maxlen;
121         do {
122                 i--;
123         } while (i > 0 && path->buf[i] != '/');
124         return i;
125 }
126
127 static void write_entry(const unsigned char *sha1, struct strbuf *path,
128                         unsigned int mode, void *buffer, unsigned long size)
129 {
130         struct ustar_header header;
131         struct strbuf ext_header;
132
133         memset(&header, 0, sizeof(header));
134         strbuf_init(&ext_header, 0);
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 (verbose)
146                         fprintf(stderr, "%.*s\n", (int)path->len, path->buf);
147                 if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
148                         *header.typeflag = TYPEFLAG_DIR;
149                         mode = (mode | 0777) & ~tar_umask;
150                 } else if (S_ISLNK(mode)) {
151                         *header.typeflag = TYPEFLAG_LNK;
152                         mode |= 0777;
153                 } else if (S_ISREG(mode)) {
154                         *header.typeflag = TYPEFLAG_REG;
155                         mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
156                 } else {
157                         error("unsupported file mode: 0%o (SHA1: %s)",
158                               mode, sha1_to_hex(sha1));
159                         return;
160                 }
161                 if (path->len > sizeof(header.name)) {
162                         int plen = get_path_prefix(path, sizeof(header.prefix));
163                         int rest = path->len - plen - 1;
164                         if (plen > 0 && rest <= sizeof(header.name)) {
165                                 memcpy(header.prefix, path->buf, plen);
166                                 memcpy(header.name, path->buf + plen + 1, rest);
167                         } else {
168                                 sprintf(header.name, "%s.data",
169                                         sha1_to_hex(sha1));
170                                 strbuf_append_ext_header(&ext_header, "path",
171                                                          path->buf, path->len);
172                         }
173                 } else
174                         memcpy(header.name, path->buf, path->len);
175         }
176
177         if (S_ISLNK(mode) && buffer) {
178                 if (size > sizeof(header.linkname)) {
179                         sprintf(header.linkname, "see %s.paxheader",
180                                 sha1_to_hex(sha1));
181                         strbuf_append_ext_header(&ext_header, "linkpath",
182                                                  buffer, size);
183                 } else
184                         memcpy(header.linkname, buffer, size);
185         }
186
187         sprintf(header.mode, "%07o", mode & 07777);
188         sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
189         sprintf(header.mtime, "%011lo", archive_time);
190
191         sprintf(header.uid, "%07o", 0);
192         sprintf(header.gid, "%07o", 0);
193         strlcpy(header.uname, "root", sizeof(header.uname));
194         strlcpy(header.gname, "root", sizeof(header.gname));
195         sprintf(header.devmajor, "%07o", 0);
196         sprintf(header.devminor, "%07o", 0);
197
198         memcpy(header.magic, "ustar", 6);
199         memcpy(header.version, "00", 2);
200
201         sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
202
203         if (ext_header.len > 0) {
204                 write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
205         }
206         strbuf_release(&ext_header);
207         write_blocked(&header, sizeof(header));
208         if (S_ISREG(mode) && buffer && size > 0)
209                 write_blocked(buffer, size);
210 }
211
212 static void write_global_extended_header(const unsigned char *sha1)
213 {
214         struct strbuf ext_header;
215
216         strbuf_init(&ext_header, 0);
217         strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
218         write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
219         strbuf_release(&ext_header);
220 }
221
222 static int git_tar_config(const char *var, const char *value)
223 {
224         if (!strcmp(var, "tar.umask")) {
225                 if (!strcmp(value, "user")) {
226                         tar_umask = umask(0);
227                         umask(tar_umask);
228                 } else {
229                         tar_umask = git_config_int(var, value);
230                 }
231                 return 0;
232         }
233         return git_default_config(var, value);
234 }
235
236 static int write_tar_entry(const unsigned char *sha1,
237                            const char *base, int baselen,
238                            const char *filename, unsigned mode, int stage)
239 {
240         static struct strbuf path = STRBUF_INIT;
241         void *buffer;
242         enum object_type type;
243         unsigned long size;
244
245         strbuf_reset(&path);
246         strbuf_grow(&path, PATH_MAX);
247         strbuf_add(&path, base, baselen);
248         strbuf_addstr(&path, filename);
249         if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
250                 strbuf_addch(&path, '/');
251                 buffer = NULL;
252                 size = 0;
253         } else {
254                 buffer = sha1_file_to_archive(path.buf, sha1, mode, &type,
255                                               &size, commit);
256                 if (!buffer)
257                         die("cannot read %s", sha1_to_hex(sha1));
258         }
259
260         write_entry(sha1, &path, mode, buffer, size);
261         free(buffer);
262
263         return READ_TREE_RECURSIVE;
264 }
265
266 int write_tar_archive(struct archiver_args *args)
267 {
268         int plen = args->base ? strlen(args->base) : 0;
269
270         git_config(git_tar_config);
271
272         archive_time = args->time;
273         verbose = args->verbose;
274         commit = args->commit;
275
276         if (args->commit_sha1)
277                 write_global_extended_header(args->commit_sha1);
278
279         if (args->base && plen > 0 && args->base[plen - 1] == '/') {
280                 char *base = xstrdup(args->base);
281                 int baselen = strlen(base);
282
283                 while (baselen > 0 && base[baselen - 1] == '/')
284                         base[--baselen] = '\0';
285                 write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
286                 free(base);
287         }
288         read_tree_recursive(args->tree, args->base, plen, 0,
289                             args->pathspec, write_tar_entry);
290         write_trailer();
291
292         return 0;
293 }