Andrew's git - gitweb.git/blob - 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
  17static const char tar_tree_usage[] =
  18"git-tar-tree [--remote=<repo>] <tree-ish> [basedir]";
  19
  20static char block[BLOCKSIZE];
  21static unsigned long offset;
  22
  23static time_t archive_time;
  24static int tar_umask;
  25static int verbose;
  26
  27/* writes out the whole block, but only if it is full */
  28static 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 */
  40static 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 */
  76static 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
  87static 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 */
 105static 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
 130static 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
 143static 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
 154static 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
 241static 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
 251static 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
 282static 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
 296static 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
 345static 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
 384int 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
 412static const char *exec = "git-upload-tar";
 413
 414static 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
 458int 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
 470int 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}