Create pack_report() as a debugging aid.
[git] / archive-tar.c
1 /*
2  * Copyright (c) 2005, 2006 Rene Scharfe
3  */
4 #include "cache.h"
5 #include "commit.h"
6 #include "strbuf.h"
7 #include "tar.h"
8 #include "builtin.h"
9 #include "archive.h"
10
11 #define RECORDSIZE      (512)
12 #define BLOCKSIZE       (RECORDSIZE * 20)
13
14 static char block[BLOCKSIZE];
15 static unsigned long offset;
16
17 static time_t archive_time;
18 static int tar_umask;
19 static int verbose;
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 static void strbuf_append_string(struct strbuf *sb, const char *s)
82 {
83         int slen = strlen(s);
84         int total = sb->len + slen;
85         if (total > sb->alloc) {
86                 sb->buf = xrealloc(sb->buf, total);
87                 sb->alloc = total;
88         }
89         memcpy(sb->buf + sb->len, s, slen);
90         sb->len = total;
91 }
92
93 /*
94  * pax extended header records have the format "%u %s=%s\n".  %u contains
95  * the size of the whole string (including the %u), the first %s is the
96  * keyword, the second one is the value.  This function constructs such a
97  * string and appends it to a struct strbuf.
98  */
99 static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
100                                      const char *value, unsigned int valuelen)
101 {
102         char *p;
103         int len, total, tmp;
104
105         /* "%u %s=%s\n" */
106         len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
107         for (tmp = len; tmp > 9; tmp /= 10)
108                 len++;
109
110         total = sb->len + len;
111         if (total > sb->alloc) {
112                 sb->buf = xrealloc(sb->buf, total);
113                 sb->alloc = total;
114         }
115
116         p = sb->buf;
117         p += sprintf(p, "%u %s=", len, keyword);
118         memcpy(p, value, valuelen);
119         p += valuelen;
120         *p = '\n';
121         sb->len = total;
122 }
123
124 static unsigned int ustar_header_chksum(const struct ustar_header *header)
125 {
126         char *p = (char *)header;
127         unsigned int chksum = 0;
128         while (p < header->chksum)
129                 chksum += *p++;
130         chksum += sizeof(header->chksum) * ' ';
131         p += sizeof(header->chksum);
132         while (p < (char *)header + sizeof(struct ustar_header))
133                 chksum += *p++;
134         return chksum;
135 }
136
137 static int get_path_prefix(const struct strbuf *path, int maxlen)
138 {
139         int i = path->len;
140         if (i > maxlen)
141                 i = maxlen;
142         do {
143                 i--;
144         } while (i > 0 && path->buf[i] != '/');
145         return i;
146 }
147
148 static void write_entry(const unsigned char *sha1, struct strbuf *path,
149                         unsigned int mode, void *buffer, unsigned long size)
150 {
151         struct ustar_header header;
152         struct strbuf ext_header;
153
154         memset(&header, 0, sizeof(header));
155         ext_header.buf = NULL;
156         ext_header.len = ext_header.alloc = 0;
157
158         if (!sha1) {
159                 *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
160                 mode = 0100666;
161                 strcpy(header.name, "pax_global_header");
162         } else if (!path) {
163                 *header.typeflag = TYPEFLAG_EXT_HEADER;
164                 mode = 0100666;
165                 sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
166         } else {
167                 if (verbose)
168                         fprintf(stderr, "%.*s\n", path->len, path->buf);
169                 if (S_ISDIR(mode)) {
170                         *header.typeflag = TYPEFLAG_DIR;
171                         mode = (mode | 0777) & ~tar_umask;
172                 } else if (S_ISLNK(mode)) {
173                         *header.typeflag = TYPEFLAG_LNK;
174                         mode |= 0777;
175                 } else if (S_ISREG(mode)) {
176                         *header.typeflag = TYPEFLAG_REG;
177                         mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
178                 } else {
179                         error("unsupported file mode: 0%o (SHA1: %s)",
180                               mode, sha1_to_hex(sha1));
181                         return;
182                 }
183                 if (path->len > sizeof(header.name)) {
184                         int plen = get_path_prefix(path, sizeof(header.prefix));
185                         int rest = path->len - plen - 1;
186                         if (plen > 0 && rest <= sizeof(header.name)) {
187                                 memcpy(header.prefix, path->buf, plen);
188                                 memcpy(header.name, path->buf + plen + 1, rest);
189                         } else {
190                                 sprintf(header.name, "%s.data",
191                                         sha1_to_hex(sha1));
192                                 strbuf_append_ext_header(&ext_header, "path",
193                                                          path->buf, path->len);
194                         }
195                 } else
196                         memcpy(header.name, path->buf, path->len);
197         }
198
199         if (S_ISLNK(mode) && buffer) {
200                 if (size > sizeof(header.linkname)) {
201                         sprintf(header.linkname, "see %s.paxheader",
202                                 sha1_to_hex(sha1));
203                         strbuf_append_ext_header(&ext_header, "linkpath",
204                                                  buffer, size);
205                 } else
206                         memcpy(header.linkname, buffer, size);
207         }
208
209         sprintf(header.mode, "%07o", mode & 07777);
210         sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
211         sprintf(header.mtime, "%011lo", archive_time);
212
213         /* XXX: should we provide more meaningful info here? */
214         sprintf(header.uid, "%07o", 0);
215         sprintf(header.gid, "%07o", 0);
216         strlcpy(header.uname, "git", sizeof(header.uname));
217         strlcpy(header.gname, "git", sizeof(header.gname));
218         sprintf(header.devmajor, "%07o", 0);
219         sprintf(header.devminor, "%07o", 0);
220
221         memcpy(header.magic, "ustar", 6);
222         memcpy(header.version, "00", 2);
223
224         sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
225
226         if (ext_header.len > 0) {
227                 write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
228                 free(ext_header.buf);
229         }
230         write_blocked(&header, sizeof(header));
231         if (S_ISREG(mode) && buffer && size > 0)
232                 write_blocked(buffer, size);
233 }
234
235 static void write_global_extended_header(const unsigned char *sha1)
236 {
237         struct strbuf ext_header;
238         ext_header.buf = NULL;
239         ext_header.len = ext_header.alloc = 0;
240         strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
241         write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
242         free(ext_header.buf);
243 }
244
245 static int git_tar_config(const char *var, const char *value)
246 {
247         if (!strcmp(var, "tar.umask")) {
248                 if (!strcmp(value, "user")) {
249                         tar_umask = umask(0);
250                         umask(tar_umask);
251                 } else {
252                         tar_umask = git_config_int(var, value);
253                 }
254                 return 0;
255         }
256         return git_default_config(var, value);
257 }
258
259 static int write_tar_entry(const unsigned char *sha1,
260                            const char *base, int baselen,
261                            const char *filename, unsigned mode, int stage)
262 {
263         static struct strbuf path;
264         int filenamelen = strlen(filename);
265         void *buffer;
266         char type[20];
267         unsigned long size;
268
269         if (!path.alloc) {
270                 path.buf = xmalloc(PATH_MAX);
271                 path.alloc = PATH_MAX;
272                 path.len = path.eof = 0;
273         }
274         if (path.alloc < baselen + filenamelen) {
275                 free(path.buf);
276                 path.buf = xmalloc(baselen + filenamelen);
277                 path.alloc = baselen + filenamelen;
278         }
279         memcpy(path.buf, base, baselen);
280         memcpy(path.buf + baselen, filename, filenamelen);
281         path.len = baselen + filenamelen;
282         if (S_ISDIR(mode)) {
283                 strbuf_append_string(&path, "/");
284                 buffer = NULL;
285                 size = 0;
286         } else {
287                 buffer = read_sha1_file(sha1, type, &size);
288                 if (!buffer)
289                         die("cannot read %s", sha1_to_hex(sha1));
290         }
291
292         write_entry(sha1, &path, mode, buffer, size);
293         free(buffer);
294
295         return READ_TREE_RECURSIVE;
296 }
297
298 int write_tar_archive(struct archiver_args *args)
299 {
300         int plen = args->base ? strlen(args->base) : 0;
301
302         git_config(git_tar_config);
303
304         archive_time = args->time;
305         verbose = args->verbose;
306
307         if (args->commit_sha1)
308                 write_global_extended_header(args->commit_sha1);
309
310         if (args->base && plen > 0 && args->base[plen - 1] == '/') {
311                 char *base = xstrdup(args->base);
312                 int baselen = strlen(base);
313
314                 while (baselen > 0 && base[baselen - 1] == '/')
315                         base[--baselen] = '\0';
316                 write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
317                 free(base);
318         }
319         read_tree_recursive(args->tree, args->base, plen, 0,
320                             args->pathspec, write_tar_entry);
321         write_trailer();
322
323         return 0;
324 }