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