builtin-tar-tree.c

   1 /*
   2  * Copyright (c) 2005, 2006 Rene Scharfe
   3  */
   4 #include <time.h>
   5 #include "cache.h"
   6 #include "tree-walk.h"
   7 #include "commit.h"
   8 #include "strbuf.h"
   9 #include "tar.h"
  10 #include "builtin.h"
  11 #include "pkt-line.h"
  12 #include "archive.h"
  13
  14 #define RECORDSIZE      (512)
  15 #define BLOCKSIZE       (RECORDSIZE * 20)
  16
  17 static const char tar_tree_usage[] =
  18 "git-tar-tree [--remote=<repo>] <tree-ish> [basedir]";
  19
  20 static char block[BLOCKSIZE];
  21 static unsigned long offset;
  22
  23 static time_t archive_time;
  24 static int tar_umask;
  25 static int verbose;
  26
  27 /* writes out the whole block, but only if it is full */
  28 static void write_if_needed(void)
  29 {
  30         if (offset == BLOCKSIZE) {
  31                 write_or_die(1, block, BLOCKSIZE);
  32                 offset = 0;
  33         }
  34 }
  35
  36 /*
  37  * queues up writes, so that all our write(2) calls write exactly one
  38  * full block; pads writes to RECORDSIZE
  39  */
  40 static void write_blocked(const void *data, unsigned long size)
  41 {
  42         const char *buf = data;
  43         unsigned long tail;
  44
  45         if (offset) {
  46                 unsigned long chunk = BLOCKSIZE - offset;
  47                 if (size < chunk)
  48                         chunk = size;
  49                 memcpy(block + offset, buf, chunk);
  50                 size -= chunk;
  51                 offset += chunk;
  52                 buf += chunk;
  53                 write_if_needed();
  54         }
  55         while (size >= BLOCKSIZE) {
  56                 write_or_die(1, buf, BLOCKSIZE);
  57                 size -= BLOCKSIZE;
  58                 buf += BLOCKSIZE;
  59         }
  60         if (size) {
  61                 memcpy(block + offset, buf, size);
  62                 offset += size;
  63         }
  64         tail = offset % RECORDSIZE;
  65         if (tail)  {
  66                 memset(block + offset, 0, RECORDSIZE - tail);
  67                 offset += RECORDSIZE - tail;
  68         }
  69         write_if_needed();
  70 }
  71
  72 /*
  73  * The end of tar archives is marked by 2*512 nul bytes and after that
  74  * follows the rest of the block (if any).
  75  */
  76 static void write_trailer(void)
  77 {
  78         int tail = BLOCKSIZE - offset;
  79         memset(block + offset, 0, tail);
  80         write_or_die(1, block, BLOCKSIZE);
  81         if (tail < 2 * RECORDSIZE) {
  82                 memset(block, 0, offset);
  83                 write_or_die(1, block, BLOCKSIZE);
  84         }
  85 }
  86
  87 static void strbuf_append_string(struct strbuf *sb, const char *s)
  88 {
  89         int slen = strlen(s);
  90         int total = sb->len + slen;
  91         if (total > sb->alloc) {
  92                 sb->buf = xrealloc(sb->buf, total);
  93                 sb->alloc = total;
  94         }
  95         memcpy(sb->buf + sb->len, s, slen);
  96         sb->len = total;
  97 }
  98
  99 /*
 100  * pax extended header records have the format "%u %s=%s\n".  %u contains
 101  * the size of the whole string (including the %u), the first %s is the
 102  * keyword, the second one is the value.  This function constructs such a
 103  * string and appends it to a struct strbuf.
 104  */
 105 static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
 106                                      const char *value, unsigned int valuelen)
 107 {
 108         char *p;
 109         int len, total, tmp;
 110
 111         /* "%u %s=%s\n" */
 112         len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
 113         for (tmp = len; tmp > 9; tmp /= 10)
 114                 len++;
 115
 116         total = sb->len + len;
 117         if (total > sb->alloc) {
 118                 sb->buf = xrealloc(sb->buf, total);
 119                 sb->alloc = total;
 120         }
 121
 122         p = sb->buf;
 123         p += sprintf(p, "%u %s=", len, keyword);
 124         memcpy(p, value, valuelen);
 125         p += valuelen;
 126         *p = '\n';
 127         sb->len = total;
 128 }
 129
 130 static unsigned int ustar_header_chksum(const struct ustar_header *header)
 131 {
 132         char *p = (char *)header;
 133         unsigned int chksum = 0;
 134         while (p < header->chksum)
 135                 chksum += *p++;
 136         chksum += sizeof(header->chksum) * ' ';
 137         p += sizeof(header->chksum);
 138         while (p < (char *)header + sizeof(struct ustar_header))
 139                 chksum += *p++;
 140         return chksum;
 141 }
 142
 143 static int get_path_prefix(const struct strbuf *path, int maxlen)
 144 {
 145         int i = path->len;
 146         if (i > maxlen)
 147                 i = maxlen;
 148         do {
 149                 i--;
 150         } while (i > 0 && path->buf[i] != '/');
 151         return i;
 152 }
 153
 154 static void write_entry(const unsigned char *sha1, struct strbuf *path,
 155                         unsigned int mode, void *buffer, unsigned long size)
 156 {
 157         struct ustar_header header;
 158         struct strbuf ext_header;
 159
 160         memset(&header, 0, sizeof(header));
 161         ext_header.buf = NULL;
 162         ext_header.len = ext_header.alloc = 0;
 163
 164         if (!sha1) {
 165                 *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 166                 mode = 0100666;
 167                 strcpy(header.name, "pax_global_header");
 168         } else if (!path) {
 169                 *header.typeflag = TYPEFLAG_EXT_HEADER;
 170                 mode = 0100666;
 171                 sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 172         } else {
 173                 if (verbose)
 174                         fprintf(stderr, "%.*s\n", path->len, path->buf);
 175                 if (S_ISDIR(mode)) {
 176                         *header.typeflag = TYPEFLAG_DIR;
 177                         mode = (mode | 0777) & ~tar_umask;
 178                 } else if (S_ISLNK(mode)) {
 179                         *header.typeflag = TYPEFLAG_LNK;
 180                         mode |= 0777;
 181                 } else if (S_ISREG(mode)) {
 182                         *header.typeflag = TYPEFLAG_REG;
 183                         mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 184                 } else {
 185                         error("unsupported file mode: 0%o (SHA1: %s)",
 186                               mode, sha1_to_hex(sha1));
 187                         return;
 188                 }
 189                 if (path->len > sizeof(header.name)) {
 190                         int plen = get_path_prefix(path, sizeof(header.prefix));
 191                         int rest = path->len - plen - 1;
 192                         if (plen > 0 && rest <= sizeof(header.name)) {
 193                                 memcpy(header.prefix, path->buf, plen);
 194                                 memcpy(header.name, path->buf + plen + 1, rest);
 195                         } else {
 196                                 sprintf(header.name, "%s.data",
 197                                         sha1_to_hex(sha1));
 198                                 strbuf_append_ext_header(&ext_header, "path",
 199                                                          path->buf, path->len);
 200                         }
 201                 } else
 202                         memcpy(header.name, path->buf, path->len);
 203         }
 204
 205         if (S_ISLNK(mode) && buffer) {
 206                 if (size > sizeof(header.linkname)) {
 207                         sprintf(header.linkname, "see %s.paxheader",
 208                                 sha1_to_hex(sha1));
 209                         strbuf_append_ext_header(&ext_header, "linkpath",
 210                                                  buffer, size);
 211                 } else
 212                         memcpy(header.linkname, buffer, size);
 213         }
 214
 215         sprintf(header.mode, "%07o", mode & 07777);
 216         sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 217         sprintf(header.mtime, "%011lo", archive_time);
 218
 219         /* XXX: should we provide more meaningful info here? */
 220         sprintf(header.uid, "%07o", 0);
 221         sprintf(header.gid, "%07o", 0);
 222         strlcpy(header.uname, "git", sizeof(header.uname));
 223         strlcpy(header.gname, "git", sizeof(header.gname));
 224         sprintf(header.devmajor, "%07o", 0);
 225         sprintf(header.devminor, "%07o", 0);
 226
 227         memcpy(header.magic, "ustar", 6);
 228         memcpy(header.version, "00", 2);
 229
 230         sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 231
 232         if (ext_header.len > 0) {
 233                 write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
 234                 free(ext_header.buf);
 235         }
 236         write_blocked(&header, sizeof(header));
 237         if (S_ISREG(mode) && buffer && size > 0)
 238                 write_blocked(buffer, size);
 239 }
 240
 241 static void write_global_extended_header(const unsigned char *sha1)
 242 {
 243         struct strbuf ext_header;
 244         ext_header.buf = NULL;
 245         ext_header.len = ext_header.alloc = 0;
 246         strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 247         write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
 248         free(ext_header.buf);
 249 }
 250
 251 static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
 252 {
 253         int pathlen = path->len;
 254         struct name_entry entry;
 255
 256         while (tree_entry(tree, &entry)) {
 257                 void *eltbuf;
 258                 char elttype[20];
 259                 unsigned long eltsize;
 260
 261                 eltbuf = read_sha1_file(entry.sha1, elttype, &eltsize);
 262                 if (!eltbuf)
 263                         die("cannot read %s", sha1_to_hex(entry.sha1));
 264
 265                 path->len = pathlen;
 266                 strbuf_append_string(path, entry.path);
 267                 if (S_ISDIR(entry.mode))
 268                         strbuf_append_string(path, "/");
 269
 270                 write_entry(entry.sha1, path, entry.mode, eltbuf, eltsize);
 271
 272                 if (S_ISDIR(entry.mode)) {
 273                         struct tree_desc subtree;
 274                         subtree.buf = eltbuf;
 275                         subtree.size = eltsize;
 276                         traverse_tree(&subtree, path);
 277                 }
 278                 free(eltbuf);
 279         }
 280 }
 281
 282 static int git_tar_config(const char *var, const char *value)
 283 {
 284         if (!strcmp(var, "tar.umask")) {
 285                 if (!strcmp(value, "user")) {
 286                         tar_umask = umask(0);
 287                         umask(tar_umask);
 288                 } else {
 289                         tar_umask = git_config_int(var, value);
 290                 }
 291                 return 0;
 292         }
 293         return git_default_config(var, value);
 294 }
 295
 296 static int generate_tar(int argc, const char **argv, const char *prefix)
 297 {
 298         unsigned char sha1[20], tree_sha1[20];
 299         struct commit *commit;
 300         struct tree_desc tree;
 301         struct strbuf current_path;
 302         void *buffer;
 303
 304         current_path.buf = xmalloc(PATH_MAX);
 305         current_path.alloc = PATH_MAX;
 306         current_path.len = current_path.eof = 0;
 307
 308         git_config(git_tar_config);
 309
 310         switch (argc) {
 311         case 3:
 312                 strbuf_append_string(&current_path, argv[2]);
 313                 strbuf_append_string(&current_path, "/");
 314                 /* FALLTHROUGH */
 315         case 2:
 316                 if (get_sha1(argv[1], sha1))
 317                         die("Not a valid object name %s", argv[1]);
 318                 break;
 319         default:
 320                 usage(tar_tree_usage);
 321         }
 322
 323         commit = lookup_commit_reference_gently(sha1, 1);
 324         if (commit) {
 325                 write_global_extended_header(commit->object.sha1);
 326                 archive_time = commit->date;
 327         } else
 328                 archive_time = time(NULL);
 329
 330         tree.buf = buffer = read_object_with_reference(sha1, tree_type,
 331                                                        &tree.size, tree_sha1);
 332         if (!tree.buf)
 333                 die("not a reference to a tag, commit or tree object: %s",
 334                     sha1_to_hex(sha1));
 335
 336         if (current_path.len > 0)
 337                 write_entry(tree_sha1, &current_path, 040777, NULL, 0);
 338         traverse_tree(&tree, &current_path);
 339         write_trailer();
 340         free(buffer);
 341         free(current_path.buf);
 342         return 0;
 343 }
 344
 345 static int write_tar_entry(const unsigned char *sha1,
 346                            const char *base, int baselen,
 347                            const char *filename, unsigned mode, int stage)
 348 {
 349         static struct strbuf path;
 350         int filenamelen = strlen(filename);
 351         void *buffer;
 352         char type[20];
 353         unsigned long size;
 354
 355         if (!path.alloc) {
 356                 path.buf = xmalloc(PATH_MAX);
 357                 path.alloc = PATH_MAX;
 358                 path.len = path.eof = 0;
 359         }
 360         if (path.alloc < baselen + filenamelen) {
 361                 free(path.buf);
 362                 path.buf = xmalloc(baselen + filenamelen);
 363                 path.alloc = baselen + filenamelen;
 364         }
 365         memcpy(path.buf, base, baselen);
 366         memcpy(path.buf + baselen, filename, filenamelen);
 367         path.len = baselen + filenamelen;
 368         if (S_ISDIR(mode)) {
 369                 strbuf_append_string(&path, "/");
 370                 buffer = NULL;
 371                 size = 0;
 372         } else {
 373                 buffer = read_sha1_file(sha1, type, &size);
 374                 if (!buffer)
 375                         die("cannot read %s", sha1_to_hex(sha1));
 376         }
 377
 378         write_entry(sha1, &path, mode, buffer, size);
 379         free(buffer);
 380
 381         return READ_TREE_RECURSIVE;
 382 }
 383
 384 int write_tar_archive(struct archiver_args *args)
 385 {
 386         int plen = strlen(args->base);
 387
 388         git_config(git_tar_config);
 389
 390         archive_time = args->time;
 391         verbose = args->verbose;
 392
 393         if (args->commit_sha1)
 394                 write_global_extended_header(args->commit_sha1);
 395
 396         if (args->base && plen > 0 && args->base[plen - 1] == '/') {
 397                 char *base = xstrdup(args->base);
 398                 int baselen = strlen(base);
 399
 400                 while (baselen > 0 && base[baselen - 1] == '/')
 401                         base[--baselen] = '\0';
 402                 write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
 403                 free(base);
 404         }
 405         read_tree_recursive(args->tree, args->base, plen, 0,
 406                             args->pathspec, write_tar_entry);
 407         write_trailer();
 408
 409         return 0;
 410 }
 411
 412 static const char *exec = "git-upload-tar";
 413
 414 static int remote_tar(int argc, const char **argv)
 415 {
 416         int fd[2], ret, len;
 417         pid_t pid;
 418         char buf[1024];
 419         char *url;
 420
 421         if (argc < 3 || 4 < argc)
 422                 usage(tar_tree_usage);
 423
 424         /* --remote=<repo> */
 425         url = xstrdup(argv[1]+9);
 426         pid = git_connect(fd, url, exec);
 427         if (pid < 0)
 428                 return 1;
 429
 430         packet_write(fd[1], "want %s\n", argv[2]);
 431         if (argv[3])
 432                 packet_write(fd[1], "base %s\n", argv[3]);
 433         packet_flush(fd[1]);
 434
 435         len = packet_read_line(fd[0], buf, sizeof(buf));
 436         if (!len)
 437                 die("git-tar-tree: expected ACK/NAK, got EOF");
 438         if (buf[len-1] == '\n')
 439                 buf[--len] = 0;
 440         if (strcmp(buf, "ACK")) {
 441                 if (5 < len && !strncmp(buf, "NACK ", 5))
 442                         die("git-tar-tree: NACK %s", buf + 5);
 443                 die("git-tar-tree: protocol error");
 444         }
 445         /* expect a flush */
 446         len = packet_read_line(fd[0], buf, sizeof(buf));
 447         if (len)
 448                 die("git-tar-tree: expected a flush");
 449
 450         /* Now, start reading from fd[0] and spit it out to stdout */
 451         ret = copy_fd(fd[0], 1);
 452         close(fd[0]);
 453
 454         ret |= finish_connect(pid);
 455         return !!ret;
 456 }
 457
 458 int cmd_tar_tree(int argc, const char **argv, const char *prefix)
 459 {
 460         if (argc < 2)
 461                 usage(tar_tree_usage);
 462         if (!strncmp("--remote=", argv[1], 9))
 463                 return remote_tar(argc, argv);
 464         return generate_tar(argc, argv, prefix);
 465 }
 466
 467 /* ustar header + extended global header content */
 468 #define HEADERSIZE (2 * RECORDSIZE)
 469
 470 int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
 471 {
 472         char buffer[HEADERSIZE];
 473         struct ustar_header *header = (struct ustar_header *)buffer;
 474         char *content = buffer + RECORDSIZE;
 475         ssize_t n;
 476
 477         n = xread(0, buffer, HEADERSIZE);
 478         if (n < HEADERSIZE)
 479                 die("git-get-tar-commit-id: read error");
 480         if (header->typeflag[0] != 'g')
 481                 return 1;
 482         if (memcmp(content, "52 comment=", 11))
 483                 return 1;
 484
 485         n = xwrite(1, content + 11, 41);
 486         if (n < 41)
 487                 die("git-get-tar-commit-id: write error");
 488
 489         return 0;
 490 }