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