Andrew's git - gitweb.git/blob

   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 int write_tar_entry(struct archiver_args *args,
 127                const unsigned char *sha1, const char *path, size_t pathlen,
 128                unsigned int mode, void *buffer, unsigned long size)
 129{
 130        struct ustar_header header;
 131        struct strbuf ext_header = STRBUF_INIT;
 132        int err = 0;
 133
 134        memset(&header, 0, sizeof(header));
 135
 136        if (!sha1) {
 137                *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 138                mode = 0100666;
 139                strcpy(header.name, "pax_global_header");
 140        } else if (!path) {
 141                *header.typeflag = TYPEFLAG_EXT_HEADER;
 142                mode = 0100666;
 143                sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 144        } else {
 145                if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 146                        *header.typeflag = TYPEFLAG_DIR;
 147                        mode = (mode | 0777) & ~tar_umask;
 148                } else if (S_ISLNK(mode)) {
 149                        *header.typeflag = TYPEFLAG_LNK;
 150                        mode |= 0777;
 151                } else if (S_ISREG(mode)) {
 152                        *header.typeflag = TYPEFLAG_REG;
 153                        mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 154                } else {
 155                        return error("unsupported file mode: 0%o (SHA1: %s)",
 156                                        mode, sha1_to_hex(sha1));
 157                }
 158                if (pathlen > sizeof(header.name)) {
 159                        size_t plen = get_path_prefix(path, pathlen,
 160                                        sizeof(header.prefix));
 161                        size_t rest = pathlen - plen - 1;
 162                        if (plen > 0 && rest <= sizeof(header.name)) {
 163                                memcpy(header.prefix, path, plen);
 164                                memcpy(header.name, path + plen + 1, rest);
 165                        } else {
 166                                sprintf(header.name, "%s.data",
 167                                        sha1_to_hex(sha1));
 168                                strbuf_append_ext_header(&ext_header, "path",
 169                                                path, pathlen);
 170                        }
 171                } else
 172                        memcpy(header.name, path, pathlen);
 173        }
 174
 175        if (S_ISLNK(mode) && buffer) {
 176                if (size > sizeof(header.linkname)) {
 177                        sprintf(header.linkname, "see %s.paxheader",
 178                                sha1_to_hex(sha1));
 179                        strbuf_append_ext_header(&ext_header, "linkpath",
 180                                                 buffer, size);
 181                } else
 182                        memcpy(header.linkname, buffer, size);
 183        }
 184
 185        sprintf(header.mode, "%07o", mode & 07777);
 186        sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 187        sprintf(header.mtime, "%011lo", (unsigned long) args->time);
 188
 189        sprintf(header.uid, "%07o", 0);
 190        sprintf(header.gid, "%07o", 0);
 191        strlcpy(header.uname, "root", sizeof(header.uname));
 192        strlcpy(header.gname, "root", sizeof(header.gname));
 193        sprintf(header.devmajor, "%07o", 0);
 194        sprintf(header.devminor, "%07o", 0);
 195
 196        memcpy(header.magic, "ustar", 6);
 197        memcpy(header.version, "00", 2);
 198
 199        sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 200
 201        if (ext_header.len > 0) {
 202                err = write_tar_entry(args, sha1, NULL, 0, 0, ext_header.buf,
 203                                ext_header.len);
 204                if (err)
 205                        return err;
 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        return err;
 212}
 213
 214static int write_global_extended_header(struct archiver_args *args)
 215{
 216        const unsigned char *sha1 = args->commit_sha1;
 217        struct strbuf ext_header = STRBUF_INIT;
 218        int err;
 219
 220        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 221        err = write_tar_entry(args, NULL, NULL, 0, 0, ext_header.buf,
 222                        ext_header.len);
 223        strbuf_release(&ext_header);
 224        return err;
 225}
 226
 227static struct archiver **tar_filters;
 228static int nr_tar_filters;
 229static int alloc_tar_filters;
 230
 231static struct archiver *find_tar_filter(const char *name, int len)
 232{
 233        int i;
 234        for (i = 0; i < nr_tar_filters; i++) {
 235                struct archiver *ar = tar_filters[i];
 236                if (!strncmp(ar->name, name, len) && !ar->name[len])
 237                        return ar;
 238        }
 239        return NULL;
 240}
 241
 242static int tar_filter_config(const char *var, const char *value, void *data)
 243{
 244        struct archiver *ar;
 245        const char *dot;
 246        const char *name;
 247        const char *type;
 248        int namelen;
 249
 250        if (prefixcmp(var, "tar."))
 251                return 0;
 252        dot = strrchr(var, '.');
 253        if (dot == var + 9)
 254                return 0;
 255
 256        name = var + 4;
 257        namelen = dot - name;
 258        type = dot + 1;
 259
 260        ar = find_tar_filter(name, namelen);
 261        if (!ar) {
 262                ar = xcalloc(1, sizeof(*ar));
 263                ar->name = xmemdupz(name, namelen);
 264                ar->write_archive = write_tar_filter_archive;
 265                ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
 266                ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
 267                tar_filters[nr_tar_filters++] = ar;
 268        }
 269
 270        if (!strcmp(type, "command")) {
 271                if (!value)
 272                        return config_error_nonbool(var);
 273                free(ar->data);
 274                ar->data = xstrdup(value);
 275                return 0;
 276        }
 277        if (!strcmp(type, "remote")) {
 278                if (git_config_bool(var, value))
 279                        ar->flags |= ARCHIVER_REMOTE;
 280                else
 281                        ar->flags &= ~ARCHIVER_REMOTE;
 282                return 0;
 283        }
 284
 285        return 0;
 286}
 287
 288static int git_tar_config(const char *var, const char *value, void *cb)
 289{
 290        if (!strcmp(var, "tar.umask")) {
 291                if (value && !strcmp(value, "user")) {
 292                        tar_umask = umask(0);
 293                        umask(tar_umask);
 294                } else {
 295                        tar_umask = git_config_int(var, value);
 296                }
 297                return 0;
 298        }
 299
 300        return tar_filter_config(var, value, cb);
 301}
 302
 303static int write_tar_archive(const struct archiver *ar,
 304                             struct archiver_args *args)
 305{
 306        int err = 0;
 307
 308        if (args->commit_sha1)
 309                err = write_global_extended_header(args);
 310        if (!err)
 311                err = write_archive_entries(args, write_tar_entry);
 312        if (!err)
 313                write_trailer();
 314        return err;
 315}
 316
 317static int write_tar_filter_archive(const struct archiver *ar,
 318                                    struct archiver_args *args)
 319{
 320        struct strbuf cmd = STRBUF_INIT;
 321        struct child_process filter;
 322        const char *argv[2];
 323        int r;
 324
 325        if (!ar->data)
 326                die("BUG: tar-filter archiver called with no filter defined");
 327
 328        strbuf_addstr(&cmd, ar->data);
 329        if (args->compression_level >= 0)
 330                strbuf_addf(&cmd, " -%d", args->compression_level);
 331
 332        memset(&filter, 0, sizeof(filter));
 333        argv[0] = cmd.buf;
 334        argv[1] = NULL;
 335        filter.argv = argv;
 336        filter.use_shell = 1;
 337        filter.in = -1;
 338
 339        if (start_command(&filter) < 0)
 340                die_errno("unable to start '%s' filter", argv[0]);
 341        close(1);
 342        if (dup2(filter.in, 1) < 0)
 343                die_errno("unable to redirect descriptor");
 344        close(filter.in);
 345
 346        r = write_tar_archive(ar, args);
 347
 348        close(1);
 349        if (finish_command(&filter) != 0)
 350                die("'%s' filter reported error", argv[0]);
 351
 352        strbuf_release(&cmd);
 353        return r;
 354}
 355
 356static struct archiver tar_archiver = {
 357        "tar",
 358        write_tar_archive,
 359        ARCHIVER_REMOTE
 360};
 361
 362void init_tar_archiver(void)
 363{
 364        int i;
 365        register_archiver(&tar_archiver);
 366
 367        tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
 368        tar_filter_config("tar.tgz.remote", "true", NULL);
 369        tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
 370        tar_filter_config("tar.tar.gz.remote", "true", NULL);
 371        git_config(git_tar_config, NULL);
 372        for (i = 0; i < nr_tar_filters; i++) {
 373                /* omit any filters that never had a command configured */
 374                if (tar_filters[i]->data)
 375                        register_archiver(tar_filters[i]);
 376        }
 377}