Andrew's git - gitweb.git/blob

   1/*
   2 * Copyright (c) 2005, 2006 Rene Scharfe
   3 */
   4#include "cache.h"
   5#include "commit.h"
   6#include "tar.h"
   7#include "builtin.h"
   8#include "archive.h"
   9
  10#define RECORDSIZE      (512)
  11#define BLOCKSIZE       (RECORDSIZE * 20)
  12
  13static char block[BLOCKSIZE];
  14static unsigned long offset;
  15
  16static time_t archive_time;
  17static int tar_umask = 002;
  18static int verbose;
  19static const struct commit *commit;
  20static size_t base_len;
  21
  22/* writes out the whole block, but only if it is full */
  23static void write_if_needed(void)
  24{
  25        if (offset == BLOCKSIZE) {
  26                write_or_die(1, block, BLOCKSIZE);
  27                offset = 0;
  28        }
  29}
  30
  31/*
  32 * queues up writes, so that all our write(2) calls write exactly one
  33 * full block; pads writes to RECORDSIZE
  34 */
  35static void write_blocked(const void *data, unsigned long size)
  36{
  37        const char *buf = data;
  38        unsigned long tail;
  39
  40        if (offset) {
  41                unsigned long chunk = BLOCKSIZE - offset;
  42                if (size < chunk)
  43                        chunk = size;
  44                memcpy(block + offset, buf, chunk);
  45                size -= chunk;
  46                offset += chunk;
  47                buf += chunk;
  48                write_if_needed();
  49        }
  50        while (size >= BLOCKSIZE) {
  51                write_or_die(1, buf, BLOCKSIZE);
  52                size -= BLOCKSIZE;
  53                buf += BLOCKSIZE;
  54        }
  55        if (size) {
  56                memcpy(block + offset, buf, size);
  57                offset += size;
  58        }
  59        tail = offset % RECORDSIZE;
  60        if (tail)  {
  61                memset(block + offset, 0, RECORDSIZE - tail);
  62                offset += RECORDSIZE - tail;
  63        }
  64        write_if_needed();
  65}
  66
  67/*
  68 * The end of tar archives is marked by 2*512 nul bytes and after that
  69 * follows the rest of the block (if any).
  70 */
  71static void write_trailer(void)
  72{
  73        int tail = BLOCKSIZE - offset;
  74        memset(block + offset, 0, tail);
  75        write_or_die(1, block, BLOCKSIZE);
  76        if (tail < 2 * RECORDSIZE) {
  77                memset(block, 0, offset);
  78                write_or_die(1, block, BLOCKSIZE);
  79        }
  80}
  81
  82/*
  83 * pax extended header records have the format "%u %s=%s\n".  %u contains
  84 * the size of the whole string (including the %u), the first %s is the
  85 * keyword, the second one is the value.  This function constructs such a
  86 * string and appends it to a struct strbuf.
  87 */
  88static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
  89                                     const char *value, unsigned int valuelen)
  90{
  91        int len, tmp;
  92
  93        /* "%u %s=%s\n" */
  94        len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
  95        for (tmp = len; tmp > 9; tmp /= 10)
  96                len++;
  97
  98        strbuf_grow(sb, len);
  99        strbuf_addf(sb, "%u %s=", len, keyword);
 100        strbuf_add(sb, value, valuelen);
 101        strbuf_addch(sb, '\n');
 102}
 103
 104static unsigned int ustar_header_chksum(const struct ustar_header *header)
 105{
 106        char *p = (char *)header;
 107        unsigned int chksum = 0;
 108        while (p < header->chksum)
 109                chksum += *p++;
 110        chksum += sizeof(header->chksum) * ' ';
 111        p += sizeof(header->chksum);
 112        while (p < (char *)header + sizeof(struct ustar_header))
 113                chksum += *p++;
 114        return chksum;
 115}
 116
 117static int get_path_prefix(const struct strbuf *path, int maxlen)
 118{
 119        int i = path->len;
 120        if (i > maxlen)
 121                i = maxlen;
 122        do {
 123                i--;
 124        } while (i > 0 && path->buf[i] != '/');
 125        return i;
 126}
 127
 128static void write_entry(const unsigned char *sha1, struct strbuf *path,
 129                        unsigned int mode, void *buffer, unsigned long size)
 130{
 131        struct ustar_header header;
 132        struct strbuf ext_header;
 133
 134        memset(&header, 0, sizeof(header));
 135        strbuf_init(&ext_header, 0);
 136
 137        if (!sha1) {
 138                *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 139                mode = 0100666;
 140                strcpy(header.name, "pax_global_header");
 141        } else if (!path) {
 142                *header.typeflag = TYPEFLAG_EXT_HEADER;
 143                mode = 0100666;
 144                sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 145        } else {
 146                if (verbose)
 147                        fprintf(stderr, "%.*s\n", (int)path->len, path->buf);
 148                if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 149                        *header.typeflag = TYPEFLAG_DIR;
 150                        mode = (mode | 0777) & ~tar_umask;
 151                } else if (S_ISLNK(mode)) {
 152                        *header.typeflag = TYPEFLAG_LNK;
 153                        mode |= 0777;
 154                } else if (S_ISREG(mode)) {
 155                        *header.typeflag = TYPEFLAG_REG;
 156                        mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 157                } else {
 158                        error("unsupported file mode: 0%o (SHA1: %s)",
 159                              mode, sha1_to_hex(sha1));
 160                        return;
 161                }
 162                if (path->len > sizeof(header.name)) {
 163                        int plen = get_path_prefix(path, sizeof(header.prefix));
 164                        int rest = path->len - plen - 1;
 165                        if (plen > 0 && rest <= sizeof(header.name)) {
 166                                memcpy(header.prefix, path->buf, plen);
 167                                memcpy(header.name, path->buf + plen + 1, rest);
 168                        } else {
 169                                sprintf(header.name, "%s.data",
 170                                        sha1_to_hex(sha1));
 171                                strbuf_append_ext_header(&ext_header, "path",
 172                                                         path->buf, path->len);
 173                        }
 174                } else
 175                        memcpy(header.name, path->buf, path->len);
 176        }
 177
 178        if (S_ISLNK(mode) && buffer) {
 179                if (size > sizeof(header.linkname)) {
 180                        sprintf(header.linkname, "see %s.paxheader",
 181                                sha1_to_hex(sha1));
 182                        strbuf_append_ext_header(&ext_header, "linkpath",
 183                                                 buffer, size);
 184                } else
 185                        memcpy(header.linkname, buffer, size);
 186        }
 187
 188        sprintf(header.mode, "%07o", mode & 07777);
 189        sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 190        sprintf(header.mtime, "%011lo", archive_time);
 191
 192        sprintf(header.uid, "%07o", 0);
 193        sprintf(header.gid, "%07o", 0);
 194        strlcpy(header.uname, "root", sizeof(header.uname));
 195        strlcpy(header.gname, "root", sizeof(header.gname));
 196        sprintf(header.devmajor, "%07o", 0);
 197        sprintf(header.devminor, "%07o", 0);
 198
 199        memcpy(header.magic, "ustar", 6);
 200        memcpy(header.version, "00", 2);
 201
 202        sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 203
 204        if (ext_header.len > 0) {
 205                write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
 206        }
 207        strbuf_release(&ext_header);
 208        write_blocked(&header, sizeof(header));
 209        if (S_ISREG(mode) && buffer && size > 0)
 210                write_blocked(buffer, size);
 211}
 212
 213static void write_global_extended_header(const unsigned char *sha1)
 214{
 215        struct strbuf ext_header;
 216
 217        strbuf_init(&ext_header, 0);
 218        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 219        write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
 220        strbuf_release(&ext_header);
 221}
 222
 223static int git_tar_config(const char *var, const char *value, void *cb)
 224{
 225        if (!strcmp(var, "tar.umask")) {
 226                if (value && !strcmp(value, "user")) {
 227                        tar_umask = umask(0);
 228                        umask(tar_umask);
 229                } else {
 230                        tar_umask = git_config_int(var, value);
 231                }
 232                return 0;
 233        }
 234        return git_default_config(var, value, cb);
 235}
 236
 237static int write_tar_entry(const unsigned char *sha1,
 238                           const char *base, int baselen,
 239                           const char *filename, unsigned mode, int stage)
 240{
 241        static struct strbuf path = STRBUF_INIT;
 242        void *buffer;
 243        enum object_type type;
 244        unsigned long size;
 245
 246        strbuf_reset(&path);
 247        strbuf_grow(&path, PATH_MAX);
 248        strbuf_add(&path, base, baselen);
 249        strbuf_addstr(&path, filename);
 250        if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 251                strbuf_addch(&path, '/');
 252                buffer = NULL;
 253                size = 0;
 254        } else {
 255                buffer = sha1_file_to_archive(path.buf + base_len, sha1, mode,
 256                                &type, &size, commit);
 257                if (!buffer)
 258                        die("cannot read %s", sha1_to_hex(sha1));
 259        }
 260
 261        write_entry(sha1, &path, mode, buffer, size);
 262        free(buffer);
 263
 264        return READ_TREE_RECURSIVE;
 265}
 266
 267int write_tar_archive(struct archiver_args *args)
 268{
 269        int plen = args->base ? strlen(args->base) : 0;
 270
 271        git_config(git_tar_config, NULL);
 272
 273        archive_time = args->time;
 274        verbose = args->verbose;
 275        commit = args->commit;
 276        base_len = args->base ? strlen(args->base) : 0;
 277
 278        if (args->commit_sha1)
 279                write_global_extended_header(args->commit_sha1);
 280
 281        if (args->base && plen > 0 && args->base[plen - 1] == '/') {
 282                char *base = xstrdup(args->base);
 283                int baselen = strlen(base);
 284
 285                while (baselen > 0 && base[baselen - 1] == '/')
 286                        base[--baselen] = '\0';
 287                write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
 288                free(base);
 289        }
 290        read_tree_recursive(args->tree, args->base, plen, 0,
 291                            args->pathspec, write_tar_entry);
 292        write_trailer();
 293
 294        return 0;
 295}