archival/libunarchive/get_header_tar.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify
   3  *  it under the terms of the GNU General Public License as published by
   4  *  the Free Software Foundation; either version 2 of the License, or
   5  *  (at your option) any later version.
   6  *
   7  *  This program is distributed in the hope that it will be useful,
   8  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  *  GNU Library General Public License for more details.
  11  *
  12  *  You should have received a copy of the GNU General Public License
  13  *  along with this program; if not, write to the Free Software
  14  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include "unarchive.h"
  21 #include "libbb.h"
  22
  23 extern char get_header_tar(archive_handle_t *archive_handle)
  24 {
  25         file_header_t *file_header = archive_handle->file_header;
  26         union {
  27                 unsigned char raw[512];
  28                 struct {
  29                         char name[100]; /*   0-99 */
  30                         char mode[8];   /* 100-107 */
  31                         char uid[8];    /* 108-115 */
  32                         char gid[8];    /* 116-123 */
  33                         char size[12];  /* 124-135 */
  34                         char mtime[12]; /* 136-147 */
  35                         char chksum[8]; /* 148-155 */
  36                         char typeflag;  /* 156-156 */
  37                         char linkname[100];     /* 157-256 */
  38                         char magic[6];  /* 257-262 */
  39                         char version[2];        /* 263-264 */
  40                         char uname[32]; /* 265-296 */
  41                         char gname[32]; /* 297-328 */
  42                         char devmajor[8];       /* 329-336 */
  43                         char devminor[8];       /* 337-344 */
  44                         char prefix[155];       /* 345-499 */
  45                         char padding[12];       /* 500-512 */
  46                 } formated;
  47         } tar;
  48         long sum = 0;
  49         long i;
  50
  51         /* Align header */
  52         archive_handle->offset += data_align(archive_handle->src_fd, archive_handle->offset, 512);
  53
  54         if (xread_all_eof(archive_handle->src_fd, tar.raw, 512) == 0) {
  55                 /* End of file */
  56                 return(EXIT_FAILURE);
  57         }
  58         archive_handle->offset += 512;
  59
  60         /* If there is no filename its an empty header */
  61         if (tar.formated.name[0] == 0) {
  62                 return(EXIT_SUCCESS);
  63         }
  64
  65         /* Check header has valid magic, "ustar" is for the proper tar
  66          * 0's are for the old tar format
  67          */
  68         if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
  69 #ifdef CONFIG_FEATURE_TAR_OLD_FORMAT
  70                 if (strncmp(tar.formated.magic, "\0\0\0\0\0", 5) != 0)
  71 #endif
  72                         error_msg_and_die("Invalid tar magic");
  73         }
  74
  75         /* Do checksum on headers */
  76         for (i =  0; i < 148 ; i++) {
  77                 sum += tar.raw[i];
  78         }
  79         sum += ' ' * 8;
  80         for (i =  156; i < 512 ; i++) {
  81                 sum += tar.raw[i];
  82         }
  83         if (sum != strtol(tar.formated.chksum, NULL, 8)) {
  84                 error_msg("Invalid tar header checksum");
  85                 return(EXIT_FAILURE);
  86         }
  87
  88         /* convert to type'ed variables */
  89         if (tar.formated.prefix[0] == 0) {
  90                 file_header->name = strdup(tar.formated.name);
  91         } else {
  92                 file_header->name = concat_path_file(tar.formated.prefix, tar.formated.name);
  93         }
  94         file_header->mode = strtol(tar.formated.mode, NULL, 8);
  95         file_header->uid = strtol(tar.formated.uid, NULL, 8);
  96         file_header->gid = strtol(tar.formated.gid, NULL, 8);
  97         file_header->size = strtol(tar.formated.size, NULL, 8);
  98         file_header->mtime = strtol(tar.formated.mtime, NULL, 8);
  99         file_header->link_name = (tar.formated.linkname[0] != '\0') ?
 100             xstrdup(tar.formated.linkname) : NULL;
 101         file_header->device = (dev_t) ((strtol(tar.formated.devmajor, NULL, 8) << 8) +
 102                                  strtol(tar.formated.devminor, NULL, 8));
 103
 104 #if defined CONFIG_FEATURE_TAR_OLD_FORMAT || defined CONFIG_FEATURE_GNUTAR_LONG_FILENAME
 105         /* Fix mode, used by the old format */
 106         switch (tar.formated.typeflag) {
 107 # ifdef CONFIG_FEATURE_TAR_OLD_FORMAT
 108         case 0:
 109                 file_header->mode |= S_IFREG;
 110                 break;
 111         case 1:
 112                 error_msg("Internal hard link not supported");
 113                 break;
 114         case 2:
 115                 file_header->mode |= S_IFLNK;
 116                 break;
 117         case 3:
 118                 file_header->mode |= S_IFCHR;
 119                 break;
 120         case 4:
 121                 file_header->mode |= S_IFBLK;
 122                 break;
 123         case 5:
 124                 file_header->mode |= S_IFDIR;
 125                 break;
 126         case 6:
 127                 file_header->mode |= S_IFIFO;
 128                 break;
 129 # endif
 130 # ifdef CONFIG_FEATURE_GNUTAR_LONG_FILENAME
 131         case 'L': {
 132                         char *longname;
 133
 134                         longname = xmalloc(file_header->size + 1);
 135                         xread_all(archive_handle->src_fd, longname, file_header->size);
 136                         longname[file_header->size] = '\0';
 137                         archive_handle->offset += file_header->size;
 138
 139                         get_header_tar(archive_handle);
 140                         file_header->name = longname;
 141                         break;
 142                 }
 143         case 'K': {
 144                         char *linkname;
 145
 146                         linkname = xmalloc(file_header->size + 1);
 147                         xread_all(archive_handle->src_fd, linkname, file_header->size);
 148                         linkname[file_header->size] = '\0';
 149                         archive_handle->offset += file_header->size;
 150
 151                         get_header_tar(archive_handle);
 152                         file_header->name = linkname;
 153                         break;
 154                 }
 155 # endif
 156         }
 157 #endif
 158         if (archive_handle->filter(archive_handle->accept, archive_handle->reject, archive_handle->file_header->name) == EXIT_SUCCESS) {
 159                 archive_handle->action_header(archive_handle->file_header);
 160                 archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
 161                 archive_handle->action_data(archive_handle);
 162         } else {
 163                 data_skip(archive_handle);
 164         }
 165         archive_handle->offset += file_header->size;
 166
 167         return(EXIT_SUCCESS);
 168 }
 169