Andrew's git - gitweb.git/blob

   1/*
   2 * Copyright (c) 2005, 2006 Rene Scharfe
   3 */
   4#include <time.h>
   5#include "cache.h"
   6#include "commit.h"
   7#include "strbuf.h"
   8#include "tar.h"
   9#include "builtin.h"
  10#include "archive.h"
  11
  12#define RECORDSIZE      (512)
  13#define BLOCKSIZE       (RECORDSIZE * 20)
  14
  15static char block[BLOCKSIZE];
  16static unsigned long offset;
  17
  18static time_t archive_time;
  19static int tar_umask;
  20static int verbose;
  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
  82static void strbuf_append_string(struct strbuf *sb, const char *s)
  83{
  84        int slen = strlen(s);
  85        int total = sb->len + slen;
  86        if (total > sb->alloc) {
  87                sb->buf = xrealloc(sb->buf, total);
  88                sb->alloc = total;
  89        }
  90        memcpy(sb->buf + sb->len, s, slen);
  91        sb->len = total;
  92}
  93
  94/*
  95 * pax extended header records have the format "%u %s=%s\n".  %u contains
  96 * the size of the whole string (including the %u), the first %s is the
  97 * keyword, the second one is the value.  This function constructs such a
  98 * string and appends it to a struct strbuf.
  99 */
 100static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
 101                                     const char *value, unsigned int valuelen)
 102{
 103        char *p;
 104        int len, total, tmp;
 105
 106        /* "%u %s=%s\n" */
 107        len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
 108        for (tmp = len; tmp > 9; tmp /= 10)
 109                len++;
 110
 111        total = sb->len + len;
 112        if (total > sb->alloc) {
 113                sb->buf = xrealloc(sb->buf, total);
 114                sb->alloc = total;
 115        }
 116
 117        p = sb->buf;
 118        p += sprintf(p, "%u %s=", len, keyword);
 119        memcpy(p, value, valuelen);
 120        p += valuelen;
 121        *p = '\n';
 122        sb->len = total;
 123}
 124
 125static unsigned int ustar_header_chksum(const struct ustar_header *header)
 126{
 127        char *p = (char *)header;
 128        unsigned int chksum = 0;
 129        while (p < header->chksum)
 130                chksum += *p++;
 131        chksum += sizeof(header->chksum) * ' ';
 132        p += sizeof(header->chksum);
 133        while (p < (char *)header + sizeof(struct ustar_header))
 134                chksum += *p++;
 135        return chksum;
 136}
 137
 138static int get_path_prefix(const struct strbuf *path, int maxlen)
 139{
 140        int i = path->len;
 141        if (i > maxlen)
 142                i = maxlen;
 143        do {
 144                i--;
 145        } while (i > 0 && path->buf[i] != '/');
 146        return i;
 147}
 148
 149static void write_entry(const unsigned char *sha1, struct strbuf *path,
 150                        unsigned int mode, void *buffer, unsigned long size)
 151{
 152        struct ustar_header header;
 153        struct strbuf ext_header;
 154
 155        memset(&header, 0, sizeof(header));
 156        ext_header.buf = NULL;
 157        ext_header.len = ext_header.alloc = 0;
 158
 159        if (!sha1) {
 160                *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 161                mode = 0100666;
 162                strcpy(header.name, "pax_global_header");
 163        } else if (!path) {
 164                *header.typeflag = TYPEFLAG_EXT_HEADER;
 165                mode = 0100666;
 166                sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 167        } else {
 168                if (verbose)
 169                        fprintf(stderr, "%.*s\n", path->len, path->buf);
 170                if (S_ISDIR(mode)) {
 171                        *header.typeflag = TYPEFLAG_DIR;
 172                        mode = (mode | 0777) & ~tar_umask;
 173                } else if (S_ISLNK(mode)) {
 174                        *header.typeflag = TYPEFLAG_LNK;
 175                        mode |= 0777;
 176                } else if (S_ISREG(mode)) {
 177                        *header.typeflag = TYPEFLAG_REG;
 178                        mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 179                } else {
 180                        error("unsupported file mode: 0%o (SHA1: %s)",
 181                              mode, sha1_to_hex(sha1));
 182                        return;
 183                }
 184                if (path->len > sizeof(header.name)) {
 185                        int plen = get_path_prefix(path, sizeof(header.prefix));
 186                        int rest = path->len - plen - 1;
 187                        if (plen > 0 && rest <= sizeof(header.name)) {
 188                                memcpy(header.prefix, path->buf, plen);
 189                                memcpy(header.name, path->buf + plen + 1, rest);
 190                        } else {
 191                                sprintf(header.name, "%s.data",
 192                                        sha1_to_hex(sha1));
 193                                strbuf_append_ext_header(&ext_header, "path",
 194                                                         path->buf, path->len);
 195                        }
 196                } else
 197                        memcpy(header.name, path->buf, path->len);
 198        }
 199
 200        if (S_ISLNK(mode) && buffer) {
 201                if (size > sizeof(header.linkname)) {
 202                        sprintf(header.linkname, "see %s.paxheader",
 203                                sha1_to_hex(sha1));
 204                        strbuf_append_ext_header(&ext_header, "linkpath",
 205                                                 buffer, size);
 206                } else
 207                        memcpy(header.linkname, buffer, size);
 208        }
 209
 210        sprintf(header.mode, "%07o", mode & 07777);
 211        sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 212        sprintf(header.mtime, "%011lo", archive_time);
 213
 214        /* XXX: should we provide more meaningful info here? */
 215        sprintf(header.uid, "%07o", 0);
 216        sprintf(header.gid, "%07o", 0);
 217        strlcpy(header.uname, "git", sizeof(header.uname));
 218        strlcpy(header.gname, "git", sizeof(header.gname));
 219        sprintf(header.devmajor, "%07o", 0);
 220        sprintf(header.devminor, "%07o", 0);
 221
 222        memcpy(header.magic, "ustar", 6);
 223        memcpy(header.version, "00", 2);
 224
 225        sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 226
 227        if (ext_header.len > 0) {
 228                write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
 229                free(ext_header.buf);
 230        }
 231        write_blocked(&header, sizeof(header));
 232        if (S_ISREG(mode) && buffer && size > 0)
 233                write_blocked(buffer, size);
 234}
 235
 236static void write_global_extended_header(const unsigned char *sha1)
 237{
 238        struct strbuf ext_header;
 239        ext_header.buf = NULL;
 240        ext_header.len = ext_header.alloc = 0;
 241        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 242        write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
 243        free(ext_header.buf);
 244}
 245
 246static int git_tar_config(const char *var, const char *value)
 247{
 248        if (!strcmp(var, "tar.umask")) {
 249                if (!strcmp(value, "user")) {
 250                        tar_umask = umask(0);
 251                        umask(tar_umask);
 252                } else {
 253                        tar_umask = git_config_int(var, value);
 254                }
 255                return 0;
 256        }
 257        return git_default_config(var, value);
 258}
 259
 260static int write_tar_entry(const unsigned char *sha1,
 261                           const char *base, int baselen,
 262                           const char *filename, unsigned mode, int stage)
 263{
 264        static struct strbuf path;
 265        int filenamelen = strlen(filename);
 266        void *buffer;
 267        char type[20];
 268        unsigned long size;
 269
 270        if (!path.alloc) {
 271                path.buf = xmalloc(PATH_MAX);
 272                path.alloc = PATH_MAX;
 273                path.len = path.eof = 0;
 274        }
 275        if (path.alloc < baselen + filenamelen) {
 276                free(path.buf);
 277                path.buf = xmalloc(baselen + filenamelen);
 278                path.alloc = baselen + filenamelen;
 279        }
 280        memcpy(path.buf, base, baselen);
 281        memcpy(path.buf + baselen, filename, filenamelen);
 282        path.len = baselen + filenamelen;
 283        if (S_ISDIR(mode)) {
 284                strbuf_append_string(&path, "/");
 285                buffer = NULL;
 286                size = 0;
 287        } else {
 288                buffer = read_sha1_file(sha1, type, &size);
 289                if (!buffer)
 290                        die("cannot read %s", sha1_to_hex(sha1));
 291        }
 292
 293        write_entry(sha1, &path, mode, buffer, size);
 294        free(buffer);
 295
 296        return READ_TREE_RECURSIVE;
 297}
 298
 299int write_tar_archive(struct archiver_args *args)
 300{
 301        int plen = args->base ? strlen(args->base) : 0;
 302
 303        git_config(git_tar_config);
 304
 305        archive_time = args->time;
 306        verbose = args->verbose;
 307
 308        if (args->commit_sha1)
 309                write_global_extended_header(args->commit_sha1);
 310
 311        if (args->base && plen > 0 && args->base[plen - 1] == '/') {
 312                char *base = xstrdup(args->base);
 313                int baselen = strlen(base);
 314
 315                while (baselen > 0 && base[baselen - 1] == '/')
 316                        base[--baselen] = '\0';
 317                write_tar_entry(args->tree->object.sha1, "", 0, base, 040777, 0);
 318                free(base);
 319        }
 320        read_tree_recursive(args->tree, args->base, plen, 0,
 321                            args->pathspec, write_tar_entry);
 322        write_trailer();
 323
 324        return 0;
 325}