Andrew's git - gitweb.git/blob

1727ab90ae1e9fd9584681de956038e34715b135
   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, const char *path, size_t pathlen,
 165                unsigned int mode, void *buffer, unsigned long size)
 166{
 167        struct ustar_header header;
 168        struct strbuf ext_header = STRBUF_INIT;
 169        int err = 0;
 170
 171        memset(&header, 0, sizeof(header));
 172
 173        if (!sha1) {
 174                die("BUG: sha1 == NULL is not supported");
 175        } else if (!path) {
 176                die("BUG: path == NULL is not supported");
 177        } else {
 178                if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 179                        *header.typeflag = TYPEFLAG_DIR;
 180                        mode = (mode | 0777) & ~tar_umask;
 181                } else if (S_ISLNK(mode)) {
 182                        *header.typeflag = TYPEFLAG_LNK;
 183                        mode |= 0777;
 184                } else if (S_ISREG(mode)) {
 185                        *header.typeflag = TYPEFLAG_REG;
 186                        mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 187                } else {
 188                        return error("unsupported file mode: 0%o (SHA1: %s)",
 189                                        mode, sha1_to_hex(sha1));
 190                }
 191                if (pathlen > sizeof(header.name)) {
 192                        size_t plen = get_path_prefix(path, pathlen,
 193                                        sizeof(header.prefix));
 194                        size_t rest = pathlen - plen - 1;
 195                        if (plen > 0 && rest <= sizeof(header.name)) {
 196                                memcpy(header.prefix, path, plen);
 197                                memcpy(header.name, path + plen + 1, rest);
 198                        } else {
 199                                sprintf(header.name, "%s.data",
 200                                        sha1_to_hex(sha1));
 201                                strbuf_append_ext_header(&ext_header, "path",
 202                                                path, pathlen);
 203                        }
 204                } else
 205                        memcpy(header.name, path, pathlen);
 206        }
 207
 208        if (S_ISLNK(mode) && buffer) {
 209                if (size > sizeof(header.linkname)) {
 210                        sprintf(header.linkname, "see %s.paxheader",
 211                                sha1_to_hex(sha1));
 212                        strbuf_append_ext_header(&ext_header, "linkpath",
 213                                                 buffer, size);
 214                } else
 215                        memcpy(header.linkname, buffer, size);
 216        }
 217
 218        prepare_header(args, &header, mode, size);
 219
 220        if (ext_header.len > 0) {
 221                err = write_extended_header(args, sha1, ext_header.buf,
 222                                            ext_header.len);
 223                if (err)
 224                        return err;
 225        }
 226        strbuf_release(&ext_header);
 227        write_blocked(&header, sizeof(header));
 228        if (S_ISREG(mode) && buffer && size > 0)
 229                write_blocked(buffer, size);
 230        return err;
 231}
 232
 233static int write_global_extended_header(struct archiver_args *args)
 234{
 235        const unsigned char *sha1 = args->commit_sha1;
 236        struct strbuf ext_header = STRBUF_INIT;
 237        struct ustar_header header;
 238        unsigned int mode;
 239        int err = 0;
 240
 241        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 242        memset(&header, 0, sizeof(header));
 243        *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 244        mode = 0100666;
 245        strcpy(header.name, "pax_global_header");
 246        prepare_header(args, &header, mode, ext_header.len);
 247        write_blocked(&header, sizeof(header));
 248        write_blocked(ext_header.buf, ext_header.len);
 249        strbuf_release(&ext_header);
 250        return err;
 251}
 252
 253static struct archiver **tar_filters;
 254static int nr_tar_filters;
 255static int alloc_tar_filters;
 256
 257static struct archiver *find_tar_filter(const char *name, int len)
 258{
 259        int i;
 260        for (i = 0; i < nr_tar_filters; i++) {
 261                struct archiver *ar = tar_filters[i];
 262                if (!strncmp(ar->name, name, len) && !ar->name[len])
 263                        return ar;
 264        }
 265        return NULL;
 266}
 267
 268static int tar_filter_config(const char *var, const char *value, void *data)
 269{
 270        struct archiver *ar;
 271        const char *dot;
 272        const char *name;
 273        const char *type;
 274        int namelen;
 275
 276        if (prefixcmp(var, "tar."))
 277                return 0;
 278        dot = strrchr(var, '.');
 279        if (dot == var + 9)
 280                return 0;
 281
 282        name = var + 4;
 283        namelen = dot - name;
 284        type = dot + 1;
 285
 286        ar = find_tar_filter(name, namelen);
 287        if (!ar) {
 288                ar = xcalloc(1, sizeof(*ar));
 289                ar->name = xmemdupz(name, namelen);
 290                ar->write_archive = write_tar_filter_archive;
 291                ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
 292                ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
 293                tar_filters[nr_tar_filters++] = ar;
 294        }
 295
 296        if (!strcmp(type, "command")) {
 297                if (!value)
 298                        return config_error_nonbool(var);
 299                free(ar->data);
 300                ar->data = xstrdup(value);
 301                return 0;
 302        }
 303        if (!strcmp(type, "remote")) {
 304                if (git_config_bool(var, value))
 305                        ar->flags |= ARCHIVER_REMOTE;
 306                else
 307                        ar->flags &= ~ARCHIVER_REMOTE;
 308                return 0;
 309        }
 310
 311        return 0;
 312}
 313
 314static int git_tar_config(const char *var, const char *value, void *cb)
 315{
 316        if (!strcmp(var, "tar.umask")) {
 317                if (value && !strcmp(value, "user")) {
 318                        tar_umask = umask(0);
 319                        umask(tar_umask);
 320                } else {
 321                        tar_umask = git_config_int(var, value);
 322                }
 323                return 0;
 324        }
 325
 326        return tar_filter_config(var, value, cb);
 327}
 328
 329static int write_tar_archive(const struct archiver *ar,
 330                             struct archiver_args *args)
 331{
 332        int err = 0;
 333
 334        if (args->commit_sha1)
 335                err = write_global_extended_header(args);
 336        if (!err)
 337                err = write_archive_entries(args, write_tar_entry);
 338        if (!err)
 339                write_trailer();
 340        return err;
 341}
 342
 343static int write_tar_filter_archive(const struct archiver *ar,
 344                                    struct archiver_args *args)
 345{
 346        struct strbuf cmd = STRBUF_INIT;
 347        struct child_process filter;
 348        const char *argv[2];
 349        int r;
 350
 351        if (!ar->data)
 352                die("BUG: tar-filter archiver called with no filter defined");
 353
 354        strbuf_addstr(&cmd, ar->data);
 355        if (args->compression_level >= 0)
 356                strbuf_addf(&cmd, " -%d", args->compression_level);
 357
 358        memset(&filter, 0, sizeof(filter));
 359        argv[0] = cmd.buf;
 360        argv[1] = NULL;
 361        filter.argv = argv;
 362        filter.use_shell = 1;
 363        filter.in = -1;
 364
 365        if (start_command(&filter) < 0)
 366                die_errno("unable to start '%s' filter", argv[0]);
 367        close(1);
 368        if (dup2(filter.in, 1) < 0)
 369                die_errno("unable to redirect descriptor");
 370        close(filter.in);
 371
 372        r = write_tar_archive(ar, args);
 373
 374        close(1);
 375        if (finish_command(&filter) != 0)
 376                die("'%s' filter reported error", argv[0]);
 377
 378        strbuf_release(&cmd);
 379        return r;
 380}
 381
 382static struct archiver tar_archiver = {
 383        "tar",
 384        write_tar_archive,
 385        ARCHIVER_REMOTE
 386};
 387
 388void init_tar_archiver(void)
 389{
 390        int i;
 391        register_archiver(&tar_archiver);
 392
 393        tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
 394        tar_filter_config("tar.tgz.remote", "true", NULL);
 395        tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
 396        tar_filter_config("tar.tar.gz.remote", "true", NULL);
 397        git_config(git_tar_config, NULL);
 398        for (i = 0; i < nr_tar_filters; i++) {
 399                /* omit any filters that never had a command configured */
 400                if (tar_filters[i]->data)
 401                        register_archiver(tar_filters[i]);
 402        }
 403}