Andrew's git - gitweb.git/blob

f646c5bd6e01f07e6b6046e465ff9044d20f0c8f
   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>] <ent> [basedir]";
  18
  19static char block[BLOCKSIZE];
  20static unsigned long offset;
  21
  22static time_t archive_time;
  23
  24/* tries hard to write, either succeeds or dies in the attempt */
  25static void reliable_write(void *buf, unsigned long size)
  26{
  27        while (size > 0) {
  28                long ret = xwrite(1, buf, size);
  29                if (ret < 0) {
  30                        if (errno == EPIPE)
  31                                exit(0);
  32                        die("git-tar-tree: %s", strerror(errno));
  33                } else if (!ret) {
  34                        die("git-tar-tree: disk full?");
  35                }
  36                size -= ret;
  37                buf += ret;
  38        }
  39}
  40
  41/* writes out the whole block, but only if it is full */
  42static void write_if_needed(void)
  43{
  44        if (offset == BLOCKSIZE) {
  45                reliable_write(block, BLOCKSIZE);
  46                offset = 0;
  47        }
  48}
  49
  50/*
  51 * queues up writes, so that all our write(2) calls write exactly one
  52 * full block; pads writes to RECORDSIZE
  53 */
  54static void write_blocked(void *buf, unsigned long size)
  55{
  56        unsigned long tail;
  57
  58        if (offset) {
  59                unsigned long chunk = BLOCKSIZE - offset;
  60                if (size < chunk)
  61                        chunk = size;
  62                memcpy(block + offset, buf, chunk);
  63                size -= chunk;
  64                offset += chunk;
  65                buf += chunk;
  66                write_if_needed();
  67        }
  68        while (size >= BLOCKSIZE) {
  69                reliable_write(buf, BLOCKSIZE);
  70                size -= BLOCKSIZE;
  71                buf += BLOCKSIZE;
  72        }
  73        if (size) {
  74                memcpy(block + offset, buf, size);
  75                offset += size;
  76        }
  77        tail = offset % RECORDSIZE;
  78        if (tail)  {
  79                memset(block + offset, 0, RECORDSIZE - tail);
  80                offset += RECORDSIZE - tail;
  81        }
  82        write_if_needed();
  83}
  84
  85/*
  86 * The end of tar archives is marked by 2*512 nul bytes and after that
  87 * follows the rest of the block (if any).
  88 */
  89static void write_trailer(void)
  90{
  91        int tail = BLOCKSIZE - offset;
  92        memset(block + offset, 0, tail);
  93        reliable_write(block, BLOCKSIZE);
  94        if (tail < 2 * RECORDSIZE) {
  95                memset(block, 0, offset);
  96                reliable_write(block, BLOCKSIZE);
  97        }
  98}
  99
 100static void strbuf_append_string(struct strbuf *sb, const char *s)
 101{
 102        int slen = strlen(s);
 103        int total = sb->len + slen;
 104        if (total > sb->alloc) {
 105                sb->buf = xrealloc(sb->buf, total);
 106                sb->alloc = total;
 107        }
 108        memcpy(sb->buf + sb->len, s, slen);
 109        sb->len = total;
 110}
 111
 112/*
 113 * pax extended header records have the format "%u %s=%s\n".  %u contains
 114 * the size of the whole string (including the %u), the first %s is the
 115 * keyword, the second one is the value.  This function constructs such a
 116 * string and appends it to a struct strbuf.
 117 */
 118static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
 119                                     const char *value, unsigned int valuelen)
 120{
 121        char *p;
 122        int len, total, tmp;
 123
 124        /* "%u %s=%s\n" */
 125        len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
 126        for (tmp = len; tmp > 9; tmp /= 10)
 127                len++;
 128
 129        total = sb->len + len;
 130        if (total > sb->alloc) {
 131                sb->buf = xrealloc(sb->buf, total);
 132                sb->alloc = total;
 133        }
 134
 135        p = sb->buf;
 136        p += sprintf(p, "%u %s=", len, keyword);
 137        memcpy(p, value, valuelen);
 138        p += valuelen;
 139        *p = '\n';
 140        sb->len = total;
 141}
 142
 143static unsigned int ustar_header_chksum(const struct ustar_header *header)
 144{
 145        char *p = (char *)header;
 146        unsigned int chksum = 0;
 147        while (p < header->chksum)
 148                chksum += *p++;
 149        chksum += sizeof(header->chksum) * ' ';
 150        p += sizeof(header->chksum);
 151        while (p < (char *)header + sizeof(struct ustar_header))
 152                chksum += *p++;
 153        return chksum;
 154}
 155
 156static int get_path_prefix(const struct strbuf *path, int maxlen)
 157{
 158        int i = path->len;
 159        if (i > maxlen)
 160                i = maxlen;
 161        do {
 162                i--;
 163        } while (i > 0 && path->buf[i] != '/');
 164        return i;
 165}
 166
 167static void write_entry(const unsigned char *sha1, struct strbuf *path,
 168                        unsigned int mode, void *buffer, unsigned long size)
 169{
 170        struct ustar_header header;
 171        struct strbuf ext_header;
 172
 173        memset(&header, 0, sizeof(header));
 174        ext_header.buf = NULL;
 175        ext_header.len = ext_header.alloc = 0;
 176
 177        if (!sha1) {
 178                *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 179                mode = 0100666;
 180                strcpy(header.name, "pax_global_header");
 181        } else if (!path) {
 182                *header.typeflag = TYPEFLAG_EXT_HEADER;
 183                mode = 0100666;
 184                sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 185        } else {
 186                if (S_ISDIR(mode)) {
 187                        *header.typeflag = TYPEFLAG_DIR;
 188                        mode |= 0777;
 189                } else if (S_ISLNK(mode)) {
 190                        *header.typeflag = TYPEFLAG_LNK;
 191                        mode |= 0777;
 192                } else if (S_ISREG(mode)) {
 193                        *header.typeflag = TYPEFLAG_REG;
 194                        mode |= (mode & 0100) ? 0777 : 0666;
 195                } else {
 196                        error("unsupported file mode: 0%o (SHA1: %s)",
 197                              mode, sha1_to_hex(sha1));
 198                        return;
 199                }
 200                if (path->len > sizeof(header.name)) {
 201                        int plen = get_path_prefix(path, sizeof(header.prefix));
 202                        int rest = path->len - plen - 1;
 203                        if (plen > 0 && rest <= sizeof(header.name)) {
 204                                memcpy(header.prefix, path->buf, plen);
 205                                memcpy(header.name, path->buf + plen + 1, rest);
 206                        } else {
 207                                sprintf(header.name, "%s.data",
 208                                        sha1_to_hex(sha1));
 209                                strbuf_append_ext_header(&ext_header, "path",
 210                                                         path->buf, path->len);
 211                        }
 212                } else
 213                        memcpy(header.name, path->buf, path->len);
 214        }
 215
 216        if (S_ISLNK(mode) && buffer) {
 217                if (size > sizeof(header.linkname)) {
 218                        sprintf(header.linkname, "see %s.paxheader",
 219                                sha1_to_hex(sha1));
 220                        strbuf_append_ext_header(&ext_header, "linkpath",
 221                                                 buffer, size);
 222                } else
 223                        memcpy(header.linkname, buffer, size);
 224        }
 225
 226        sprintf(header.mode, "%07o", mode & 07777);
 227        sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 228        sprintf(header.mtime, "%011lo", archive_time);
 229
 230        /* XXX: should we provide more meaningful info here? */
 231        sprintf(header.uid, "%07o", 0);
 232        sprintf(header.gid, "%07o", 0);
 233        safe_strncpy(header.uname, "git", sizeof(header.uname));
 234        safe_strncpy(header.gname, "git", sizeof(header.gname));
 235        sprintf(header.devmajor, "%07o", 0);
 236        sprintf(header.devminor, "%07o", 0);
 237
 238        memcpy(header.magic, "ustar", 6);
 239        memcpy(header.version, "00", 2);
 240
 241        sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 242
 243        if (ext_header.len > 0) {
 244                write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
 245                free(ext_header.buf);
 246        }
 247        write_blocked(&header, sizeof(header));
 248        if (S_ISREG(mode) && buffer && size > 0)
 249                write_blocked(buffer, size);
 250}
 251
 252static void write_global_extended_header(const unsigned char *sha1)
 253{
 254        struct strbuf ext_header;
 255        ext_header.buf = NULL;
 256        ext_header.len = ext_header.alloc = 0;
 257        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 258        write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
 259        free(ext_header.buf);
 260}
 261
 262static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
 263{
 264        int pathlen = path->len;
 265        struct name_entry entry;
 266
 267        while (tree_entry(tree, &entry)) {
 268                void *eltbuf;
 269                char elttype[20];
 270                unsigned long eltsize;
 271
 272                eltbuf = read_sha1_file(entry.sha1, elttype, &eltsize);
 273                if (!eltbuf)
 274                        die("cannot read %s", sha1_to_hex(entry.sha1));
 275
 276                path->len = pathlen;
 277                strbuf_append_string(path, entry.path);
 278                if (S_ISDIR(entry.mode))
 279                        strbuf_append_string(path, "/");
 280
 281                write_entry(entry.sha1, path, entry.mode, eltbuf, eltsize);
 282
 283                if (S_ISDIR(entry.mode)) {
 284                        struct tree_desc subtree;
 285                        subtree.buf = eltbuf;
 286                        subtree.size = eltsize;
 287                        traverse_tree(&subtree, path);
 288                }
 289                free(eltbuf);
 290        }
 291}
 292
 293static int generate_tar(int argc, const char **argv, char** envp)
 294{
 295        unsigned char sha1[20], tree_sha1[20];
 296        struct commit *commit;
 297        struct tree_desc tree;
 298        struct strbuf current_path;
 299
 300        current_path.buf = xmalloc(PATH_MAX);
 301        current_path.alloc = PATH_MAX;
 302        current_path.len = current_path.eof = 0;
 303
 304        setup_git_directory();
 305        git_config(git_default_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 = read_object_with_reference(sha1, tree_type, &tree.size,
 328                                              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(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, char **envp)
 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, envp);
 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, char **envp)
 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}