Andrew's git - gitweb.git/blob

3be0cdf35069c6e810ca61ad9faf3f0917ad2ee0
   1/*
   2 * Copyright (c) 2005, 2006 Rene Scharfe
   3 */
   4#include "cache.h"
   5#include "tar.h"
   6#include "archive.h"
   7#include "run-command.h"
   8
   9#define RECORDSIZE      (512)
  10#define BLOCKSIZE       (RECORDSIZE * 20)
  11
  12static char block[BLOCKSIZE];
  13static unsigned long offset;
  14
  15static int tar_umask = 002;
  16
  17static int write_tar_filter_archive(const struct archiver *ar,
  18                                    struct archiver_args *args);
  19
  20/* writes out the whole block, but only if it is full */
  21static void write_if_needed(void)
  22{
  23        if (offset == BLOCKSIZE) {
  24                write_or_die(1, block, BLOCKSIZE);
  25                offset = 0;
  26        }
  27}
  28
  29/*
  30 * queues up writes, so that all our write(2) calls write exactly one
  31 * full block; pads writes to RECORDSIZE
  32 */
  33static void write_blocked(const void *data, unsigned long size)
  34{
  35        const char *buf = data;
  36        unsigned long tail;
  37
  38        if (offset) {
  39                unsigned long chunk = BLOCKSIZE - offset;
  40                if (size < chunk)
  41                        chunk = size;
  42                memcpy(block + offset, buf, chunk);
  43                size -= chunk;
  44                offset += chunk;
  45                buf += chunk;
  46                write_if_needed();
  47        }
  48        while (size >= BLOCKSIZE) {
  49                write_or_die(1, buf, BLOCKSIZE);
  50                size -= BLOCKSIZE;
  51                buf += BLOCKSIZE;
  52        }
  53        if (size) {
  54                memcpy(block + offset, buf, size);
  55                offset += size;
  56        }
  57        tail = offset % RECORDSIZE;
  58        if (tail)  {
  59                memset(block + offset, 0, RECORDSIZE - tail);
  60                offset += RECORDSIZE - tail;
  61        }
  62        write_if_needed();
  63}
  64
  65/*
  66 * The end of tar archives is marked by 2*512 nul bytes and after that
  67 * follows the rest of the block (if any).
  68 */
  69static void write_trailer(void)
  70{
  71        int tail = BLOCKSIZE - offset;
  72        memset(block + offset, 0, tail);
  73        write_or_die(1, block, BLOCKSIZE);
  74        if (tail < 2 * RECORDSIZE) {
  75                memset(block, 0, offset);
  76                write_or_die(1, block, BLOCKSIZE);
  77        }
  78}
  79
  80/*
  81 * pax extended header records have the format "%u %s=%s\n".  %u contains
  82 * the size of the whole string (including the %u), the first %s is the
  83 * keyword, the second one is the value.  This function constructs such a
  84 * string and appends it to a struct strbuf.
  85 */
  86static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
  87                                     const char *value, unsigned int valuelen)
  88{
  89        int len, tmp;
  90
  91        /* "%u %s=%s\n" */
  92        len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
  93        for (tmp = len; tmp > 9; tmp /= 10)
  94                len++;
  95
  96        strbuf_grow(sb, len);
  97        strbuf_addf(sb, "%u %s=", len, keyword);
  98        strbuf_add(sb, value, valuelen);
  99        strbuf_addch(sb, '\n');
 100}
 101
 102static unsigned int ustar_header_chksum(const struct ustar_header *header)
 103{
 104        char *p = (char *)header;
 105        unsigned int chksum = 0;
 106        while (p < header->chksum)
 107                chksum += *p++;
 108        chksum += sizeof(header->chksum) * ' ';
 109        p += sizeof(header->chksum);
 110        while (p < (char *)header + sizeof(struct ustar_header))
 111                chksum += *p++;
 112        return chksum;
 113}
 114
 115static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
 116{
 117        size_t i = pathlen;
 118        if (i > maxlen)
 119                i = maxlen;
 120        do {
 121                i--;
 122        } while (i > 0 && path[i] != '/');
 123        return i;
 124}
 125
 126static void prepare_header(struct archiver_args *args,
 127                           struct ustar_header *header,
 128                           unsigned int mode, unsigned long size)
 129{
 130        sprintf(header->mode, "%07o", mode & 07777);
 131        sprintf(header->size, "%011lo", S_ISREG(mode) ? size : 0);
 132        sprintf(header->mtime, "%011lo", (unsigned long) args->time);
 133
 134        sprintf(header->uid, "%07o", 0);
 135        sprintf(header->gid, "%07o", 0);
 136        strlcpy(header->uname, "root", sizeof(header->uname));
 137        strlcpy(header->gname, "root", sizeof(header->gname));
 138        sprintf(header->devmajor, "%07o", 0);
 139        sprintf(header->devminor, "%07o", 0);
 140
 141        memcpy(header->magic, "ustar", 6);
 142        memcpy(header->version, "00", 2);
 143
 144        sprintf(header->chksum, "%07o", ustar_header_chksum(header));
 145}
 146
 147static int write_extended_header(struct archiver_args *args,
 148                                 const unsigned char *sha1,
 149                                 const void *buffer, unsigned long size)
 150{
 151        struct ustar_header header;
 152        unsigned int mode;
 153        memset(&header, 0, sizeof(header));
 154        *header.typeflag = TYPEFLAG_EXT_HEADER;
 155        mode = 0100666;
 156        sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 157        prepare_header(args, &header, mode, size);
 158        write_blocked(&header, sizeof(header));
 159        write_blocked(buffer, size);
 160        return 0;
 161}
 162
 163static int write_tar_entry(struct archiver_args *args,
 164                           const unsigned char *sha1,
 165                           const char *path, size_t pathlen,
 166                           unsigned int mode)
 167{
 168        struct ustar_header header;
 169        struct strbuf ext_header = STRBUF_INIT;
 170        unsigned int old_mode = mode;
 171        unsigned long size;
 172        void *buffer;
 173        int err = 0;
 174
 175        memset(&header, 0, sizeof(header));
 176
 177        if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 178                *header.typeflag = TYPEFLAG_DIR;
 179                mode = (mode | 0777) & ~tar_umask;
 180        } else if (S_ISLNK(mode)) {
 181                *header.typeflag = TYPEFLAG_LNK;
 182                mode |= 0777;
 183        } else if (S_ISREG(mode)) {
 184                *header.typeflag = TYPEFLAG_REG;
 185                mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 186        } else {
 187                return error("unsupported file mode: 0%o (SHA1: %s)",
 188                             mode, sha1_to_hex(sha1));
 189        }
 190        if (pathlen > sizeof(header.name)) {
 191                size_t plen = get_path_prefix(path, pathlen,
 192                                              sizeof(header.prefix));
 193                size_t rest = pathlen - plen - 1;
 194                if (plen > 0 && rest <= sizeof(header.name)) {
 195                        memcpy(header.prefix, path, plen);
 196                                memcpy(header.name, path + plen + 1, rest);
 197                } else {
 198                        sprintf(header.name, "%s.data",
 199                                sha1_to_hex(sha1));
 200                        strbuf_append_ext_header(&ext_header, "path",
 201                                                 path, pathlen);
 202                }
 203        } else
 204                memcpy(header.name, path, pathlen);
 205
 206        if (S_ISLNK(mode) || S_ISREG(mode)) {
 207                enum object_type type;
 208                buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size);
 209                if (!buffer)
 210                        return error("cannot read %s", sha1_to_hex(sha1));
 211        } else {
 212                buffer = NULL;
 213                size = 0;
 214        }
 215
 216        if (S_ISLNK(mode)) {
 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        prepare_header(args, &header, mode, size);
 227
 228        if (ext_header.len > 0) {
 229                err = write_extended_header(args, sha1, ext_header.buf,
 230                                            ext_header.len);
 231                if (err) {
 232                        free(buffer);
 233                        return err;
 234                }
 235        }
 236        strbuf_release(&ext_header);
 237        write_blocked(&header, sizeof(header));
 238        if (S_ISREG(mode) && buffer && size > 0)
 239                write_blocked(buffer, size);
 240        free(buffer);
 241        return err;
 242}
 243
 244static int write_global_extended_header(struct archiver_args *args)
 245{
 246        const unsigned char *sha1 = args->commit_sha1;
 247        struct strbuf ext_header = STRBUF_INIT;
 248        struct ustar_header header;
 249        unsigned int mode;
 250        int err = 0;
 251
 252        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 253        memset(&header, 0, sizeof(header));
 254        *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 255        mode = 0100666;
 256        strcpy(header.name, "pax_global_header");
 257        prepare_header(args, &header, mode, ext_header.len);
 258        write_blocked(&header, sizeof(header));
 259        write_blocked(ext_header.buf, ext_header.len);
 260        strbuf_release(&ext_header);
 261        return err;
 262}
 263
 264static struct archiver **tar_filters;
 265static int nr_tar_filters;
 266static int alloc_tar_filters;
 267
 268static struct archiver *find_tar_filter(const char *name, int len)
 269{
 270        int i;
 271        for (i = 0; i < nr_tar_filters; i++) {
 272                struct archiver *ar = tar_filters[i];
 273                if (!strncmp(ar->name, name, len) && !ar->name[len])
 274                        return ar;
 275        }
 276        return NULL;
 277}
 278
 279static int tar_filter_config(const char *var, const char *value, void *data)
 280{
 281        struct archiver *ar;
 282        const char *dot;
 283        const char *name;
 284        const char *type;
 285        int namelen;
 286
 287        if (prefixcmp(var, "tar."))
 288                return 0;
 289        dot = strrchr(var, '.');
 290        if (dot == var + 9)
 291                return 0;
 292
 293        name = var + 4;
 294        namelen = dot - name;
 295        type = dot + 1;
 296
 297        ar = find_tar_filter(name, namelen);
 298        if (!ar) {
 299                ar = xcalloc(1, sizeof(*ar));
 300                ar->name = xmemdupz(name, namelen);
 301                ar->write_archive = write_tar_filter_archive;
 302                ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
 303                ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
 304                tar_filters[nr_tar_filters++] = ar;
 305        }
 306
 307        if (!strcmp(type, "command")) {
 308                if (!value)
 309                        return config_error_nonbool(var);
 310                free(ar->data);
 311                ar->data = xstrdup(value);
 312                return 0;
 313        }
 314        if (!strcmp(type, "remote")) {
 315                if (git_config_bool(var, value))
 316                        ar->flags |= ARCHIVER_REMOTE;
 317                else
 318                        ar->flags &= ~ARCHIVER_REMOTE;
 319                return 0;
 320        }
 321
 322        return 0;
 323}
 324
 325static int git_tar_config(const char *var, const char *value, void *cb)
 326{
 327        if (!strcmp(var, "tar.umask")) {
 328                if (value && !strcmp(value, "user")) {
 329                        tar_umask = umask(0);
 330                        umask(tar_umask);
 331                } else {
 332                        tar_umask = git_config_int(var, value);
 333                }
 334                return 0;
 335        }
 336
 337        return tar_filter_config(var, value, cb);
 338}
 339
 340static int write_tar_archive(const struct archiver *ar,
 341                             struct archiver_args *args)
 342{
 343        int err = 0;
 344
 345        if (args->commit_sha1)
 346                err = write_global_extended_header(args);
 347        if (!err)
 348                err = write_archive_entries(args, write_tar_entry);
 349        if (!err)
 350                write_trailer();
 351        return err;
 352}
 353
 354static int write_tar_filter_archive(const struct archiver *ar,
 355                                    struct archiver_args *args)
 356{
 357        struct strbuf cmd = STRBUF_INIT;
 358        struct child_process filter;
 359        const char *argv[2];
 360        int r;
 361
 362        if (!ar->data)
 363                die("BUG: tar-filter archiver called with no filter defined");
 364
 365        strbuf_addstr(&cmd, ar->data);
 366        if (args->compression_level >= 0)
 367                strbuf_addf(&cmd, " -%d", args->compression_level);
 368
 369        memset(&filter, 0, sizeof(filter));
 370        argv[0] = cmd.buf;
 371        argv[1] = NULL;
 372        filter.argv = argv;
 373        filter.use_shell = 1;
 374        filter.in = -1;
 375
 376        if (start_command(&filter) < 0)
 377                die_errno("unable to start '%s' filter", argv[0]);
 378        close(1);
 379        if (dup2(filter.in, 1) < 0)
 380                die_errno("unable to redirect descriptor");
 381        close(filter.in);
 382
 383        r = write_tar_archive(ar, args);
 384
 385        close(1);
 386        if (finish_command(&filter) != 0)
 387                die("'%s' filter reported error", argv[0]);
 388
 389        strbuf_release(&cmd);
 390        return r;
 391}
 392
 393static struct archiver tar_archiver = {
 394        "tar",
 395        write_tar_archive,
 396        ARCHIVER_REMOTE
 397};
 398
 399void init_tar_archiver(void)
 400{
 401        int i;
 402        register_archiver(&tar_archiver);
 403
 404        tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
 405        tar_filter_config("tar.tgz.remote", "true", NULL);
 406        tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
 407        tar_filter_config("tar.tar.gz.remote", "true", NULL);
 408        git_config(git_tar_config, NULL);
 409        for (i = 0; i < nr_tar_filters; i++) {
 410                /* omit any filters that never had a command configured */
 411                if (tar_filters[i]->data)
 412                        register_archiver(tar_filters[i]);
 413        }
 414}