builtin-tar-tree.c

   1 /*
   2  * Copyright (c) 2005, 2006 Rene Scharfe
   3  */
   4 #include <time.h>
   5 #include "cache.h"
   6 #include "commit.h"
   7 #include "strbuf.h"
   8 #include "tar.h"
   9 #include "builtin.h"
  10 #include "pkt-line.h"
  11 #include "archive.h"
  12
  13 #define RECORDSIZE      (512)
  14 #define BLOCKSIZE       (RECORDSIZE * 20)
  15
  16 static const char tar_tree_usage[] =
  17 "git-tar-tree [--remote=<repo>] <tree-ish> [basedir]";
  18
  19 static char block[BLOCKSIZE];
  20 static unsigned long offset;
  21
  22 static time_t archive_time;
  23 static int tar_umask;
  24 static int verbose;
  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 (verbose)
 173                         fprintf(stderr, "%.*s\n", path->len, path->buf);
 174                 if (S_ISDIR(mode)) {
 175                         *header.typeflag = TYPEFLAG_DIR;
 176                         mode = (mode | 0777) & ~tar_umask;
 177                 } else if (S_ISLNK(mode)) {
 178                         *header.typeflag = TYPEFLAG_LNK;
 179                         mode |= 0777;
 180                 } else if (S_ISREG(mode)) {
 181                         *header.typeflag = TYPEFLAG_REG;
 182                         mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 183                 } else {
 184                         error("unsupported file mode: 0%o (SHA1: %s)",
 185                               mode, sha1_to_hex(sha1));
 186                         return;
 187                 }
 188                 if (path->len > sizeof(header.name)) {
 189                         int plen = get_path_prefix(path, sizeof(header.prefix));
 190                         int rest = path->len - plen - 1;
 191                         if (plen > 0 && rest <= sizeof(header.name)) {
 192                                 memcpy(header.prefix, path->buf, plen);
 193                                 memcpy(header.name, path->buf + plen + 1, rest);
 194                         } else {
 195                                 sprintf(header.name, "%s.data",
 196                                         sha1_to_hex(sha1));
 197                                 strbuf_append_ext_header(&ext_header, "path",
 198                                                          path->buf, path->len);
 199                         }
 200                 } else
 201                         memcpy(header.name, path->buf, path->len);
 202         }
 203
 204         if (S_ISLNK(mode) && buffer) {
 205                 if (size > sizeof(header.linkname)) {
 206                         sprintf(header.linkname, "see %s.paxheader",
 207                                 sha1_to_hex(sha1));
 208                         strbuf_append_ext_header(&ext_header, "linkpath",
 209                                                  buffer, size);
 210                 } else
 211                         memcpy(header.linkname, buffer, size);
 212         }
 213
 214         sprintf(header.mode, "%07o", mode & 07777);
 215         sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 216         sprintf(header.mtime, "%011lo", archive_time);
 217
 218         /* XXX: should we provide more meaningful info here? */
 219         sprintf(header.uid, "%07o", 0);
 220         sprintf(header.gid, "%07o", 0);
 221         strlcpy(header.uname, "git", sizeof(header.uname));
 222         strlcpy(header.gname, "git", sizeof(header.gname));
 223         sprintf(header.devmajor, "%07o", 0);
 224         sprintf(header.devminor, "%07o", 0);
 225
 226         memcpy(header.magic, "ustar", 6);
 227         memcpy(header.version, "00", 2);
 228
 229         sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 230
 231         if (ext_header.len > 0) {
 232                 write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
 233                 free(ext_header.buf);
 234         }
 235         write_blocked(&header, sizeof(header));
 236         if (S_ISREG(mode) && buffer && size > 0)
 237                 write_blocked(buffer, size);
 238 }
 239
 240 static void write_global_extended_header(const unsigned char *sha1)
 241 {
 242         struct strbuf ext_header;
 243         ext_header.buf = NULL;
 244         ext_header.len = ext_header.alloc = 0;
 245         strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 246         write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
 247         free(ext_header.buf);
 248 }
 249
 250 static int git_tar_config(const char *var, const char *value)
 251 {
 252         if (!strcmp(var, "tar.umask")) {
 253                 if (!strcmp(value, "user")) {
 254                         tar_umask = umask(0);
 255                         umask(tar_umask);
 256                 } else {
 257                         tar_umask = git_config_int(var, value);
 258                 }
 259                 return 0;
 260         }
 261         return git_default_config(var, value);
 262 }
 263
 264 static int generate_tar(int argc, const char **argv, const char *prefix)
 265 {
 266         struct archiver_args args;
 267         int result;
 268         char *base = NULL;
 269
 270         git_config(git_tar_config);
 271
 272         memset(&args, 0, sizeof(args));
 273         if (argc != 2 && argc != 3)
 274                 usage(tar_tree_usage);
 275         if (argc == 3) {
 276                 int baselen = strlen(argv[2]);
 277                 base = xmalloc(baselen + 2);
 278                 memcpy(base, argv[2], baselen);
 279                 base[baselen] = '/';
 280                 base[baselen + 1] = '\0';
 281         }
 282         args.base = base;
 283         parse_treeish_arg(argv + 1, &args, NULL);
 284
 285         result = write_tar_archive(&args);
 286         free(base);
 287
 288         return result;
 289 }
 290
 291 static int write_tar_entry(const unsigned char *sha1,
 292                            const char *base, int baselen,
 293                            const char *filename, unsigned mode, int stage)
 294 {
 295         static struct strbuf path;
 296         int filenamelen = strlen(filename);
 297         void *buffer;
 298         char type[20];
 299         unsigned long size;
 300
 301         if (!path.alloc) {
 302                 path.buf = xmalloc(PATH_MAX);
 303                 path.alloc = PATH_MAX;
 304                 path.len = path.eof = 0;
 305         }
 306         if (path.alloc < baselen + filenamelen) {
 307                 free(path.buf);
 308                 path.buf = xmalloc(baselen + filenamelen);
 309                 path.alloc = baselen + filenamelen;
 310         }
 311         memcpy(path.buf, base, baselen);
 312         memcpy(path.buf + baselen, filename, filenamelen);
 313         path.len = baselen + filenamelen;
 314         if (S_ISDIR(mode)) {
 315                 strbuf_append_string(&path, "/");
 316                 buffer = NULL;
 317                 size = 0;
 318         } else {
 319                 buffer = read_sha1_file(sha1, type, &size);
 320                 if (!buffer)
 321                         die("cannot read %s", sha1_to_hex(sha1));
 322         }
 323
 324         write_entry(sha1, &path, mode, buffer, size);
 325         free(buffer);
 326
 327         return READ_TREE_RECURSIVE;
 328 }
 329
 330 int write_tar_archive(struct archiver_args *args)
 331 {
 332         int plen = args->base ? strlen(args->base) : 0;
 333
 334         git_config(git_tar_config);
 335
 336         archive_time = args->time;
 337         verbose = args->verbose;
 338
 339         if (args->commit_sha1)
 340                 write_global_extended_header(args->commit_sha1);
 341
 342         if (args->base && plen > 0 && args->base[plen - 1] == '/') {
 343                 char *base = xstrdup(args->base);
 344                 int baselen = strlen(base);
 345
 346                 while (baselen > 0 && base[baselen - 1] == '/')
 347                         base[--baselen] = '\0';
 348                 write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
 349                 free(base);
 350         }
 351         read_tree_recursive(args->tree, args->base, plen, 0,
 352                             args->pathspec, write_tar_entry);
 353         write_trailer();
 354
 355         return 0;
 356 }
 357
 358 static const char *exec = "git-upload-tar";
 359
 360 static int remote_tar(int argc, const char **argv)
 361 {
 362         int fd[2], ret, len;
 363         pid_t pid;
 364         char buf[1024];
 365         char *url;
 366
 367         if (argc < 3 || 4 < argc)
 368                 usage(tar_tree_usage);
 369
 370         /* --remote=<repo> */
 371         url = xstrdup(argv[1]+9);
 372         pid = git_connect(fd, url, exec);
 373         if (pid < 0)
 374                 return 1;
 375
 376         packet_write(fd[1], "want %s\n", argv[2]);
 377         if (argv[3])
 378                 packet_write(fd[1], "base %s\n", argv[3]);
 379         packet_flush(fd[1]);
 380
 381         len = packet_read_line(fd[0], buf, sizeof(buf));
 382         if (!len)
 383                 die("git-tar-tree: expected ACK/NAK, got EOF");
 384         if (buf[len-1] == '\n')
 385                 buf[--len] = 0;
 386         if (strcmp(buf, "ACK")) {
 387                 if (5 < len && !strncmp(buf, "NACK ", 5))
 388                         die("git-tar-tree: NACK %s", buf + 5);
 389                 die("git-tar-tree: protocol error");
 390         }
 391         /* expect a flush */
 392         len = packet_read_line(fd[0], buf, sizeof(buf));
 393         if (len)
 394                 die("git-tar-tree: expected a flush");
 395
 396         /* Now, start reading from fd[0] and spit it out to stdout */
 397         ret = copy_fd(fd[0], 1);
 398         close(fd[0]);
 399
 400         ret |= finish_connect(pid);
 401         return !!ret;
 402 }
 403
 404 int cmd_tar_tree(int argc, const char **argv, const char *prefix)
 405 {
 406         if (argc < 2)
 407                 usage(tar_tree_usage);
 408         if (!strncmp("--remote=", argv[1], 9))
 409                 return remote_tar(argc, argv);
 410         return generate_tar(argc, argv, prefix);
 411 }
 412
 413 /* ustar header + extended global header content */
 414 #define HEADERSIZE (2 * RECORDSIZE)
 415
 416 int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix)
 417 {
 418         char buffer[HEADERSIZE];
 419         struct ustar_header *header = (struct ustar_header *)buffer;
 420         char *content = buffer + RECORDSIZE;
 421         ssize_t n;
 422
 423         n = xread(0, buffer, HEADERSIZE);
 424         if (n < HEADERSIZE)
 425                 die("git-get-tar-commit-id: read error");
 426         if (header->typeflag[0] != 'g')
 427                 return 1;
 428         if (memcmp(content, "52 comment=", 11))
 429                 return 1;
 430
 431         n = xwrite(1, content + 11, 41);
 432         if (n < 41)
 433                 die("git-get-tar-commit-id: write error");
 434
 435         return 0;
 436 }