libbb/untar.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  * NOTE: This is used by deb_extract to avoid calling the whole tar applet.
  17  * Its functionality should be merged with tar to avoid duplication
  18  */
  19
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include "libbb.h"
  24
  25 extern int untar(FILE *src_tar_file, int untar_function, char *base_path)
  26 {
  27         typedef struct raw_tar_header {
  28         char name[100];               /*   0-99 */
  29         char mode[8];                 /* 100-107 */
  30         char uid[8];                  /* 108-115 */
  31         char gid[8];                  /* 116-123 */
  32         char size[12];                /* 124-135 */
  33         char mtime[12];               /* 136-147 */
  34         char chksum[8];               /* 148-155 */
  35         char typeflag;                /* 156-156 */
  36         char linkname[100];           /* 157-256 */
  37         char magic[6];                /* 257-262 */
  38         char version[2];              /* 263-264 */
  39         char uname[32];               /* 265-296 */
  40         char gname[32];               /* 297-328 */
  41         char devmajor[8];             /* 329-336 */
  42         char devminor[8];             /* 337-344 */
  43         char prefix[155];             /* 345-499 */
  44         char padding[12];             /* 500-512 */
  45         } raw_tar_header_t;
  46
  47         raw_tar_header_t raw_tar_header;
  48         unsigned char *temp = (unsigned char *) &raw_tar_header;
  49         long i;
  50         long next_header_offset = 0;
  51         long uncompressed_count = 0;
  52         size_t size;
  53         mode_t mode;
  54
  55         while (fread((char *) &raw_tar_header, 1, 512, src_tar_file) == 512) {
  56                 long sum = 0;
  57                 char *dir = NULL;
  58
  59                 uncompressed_count += 512;
  60
  61                 /* Check header has valid magic */
  62                 if (strncmp(raw_tar_header.magic, "ustar", 5) != 0) {
  63                         /* Put this pack after TODO (check child still alive) is done */
  64                         error_msg("Invalid tar magic");
  65                         break;
  66                 }
  67
  68                 /* Do checksum on headers */
  69         for (i =  0; i < 148 ; i++) {
  70                         sum += temp[i];
  71                 }
  72         sum += ' ' * 8;
  73                 for (i =  156; i < 512 ; i++) {
  74                         sum += temp[i];
  75                 }
  76         if (sum != strtol(raw_tar_header.chksum, NULL, 8)) {
  77                         error_msg("Invalid tar header checksum");
  78                         break;
  79                 }
  80
  81                 /* convert to type'ed variables */
  82         size = strtol(raw_tar_header.size, NULL, 8);
  83                 parse_mode(raw_tar_header.mode, &mode);
  84
  85                 /* start of next header is at */
  86                 next_header_offset = uncompressed_count + size;
  87                 if (size % 512 != 0) {
  88                         next_header_offset += (512 - size % 512);
  89                 }
  90
  91                 /*
  92                  * seek to start of control file, return length
  93                  *
  94                 if (dpkg_untar_function & dpkg_untar_seek_control) {
  95                         if ((raw_tar_header.typeflag == '0') || (raw_tar_header.typeflag == '\0')) {
  96                                 char *tar_filename;
  97
  98                                 tar_filename = strrchr(raw_tar_header.name, '/');
  99                                 if (tar_filename == NULL) {
 100                                         tar_filename = strdup(raw_tar_header.name);
 101                                 } else {
 102                                         tar_filename++;
 103                                 }
 104
 105                                 if (strcmp(tar_filename, "control") == 0) {
 106                                         return(size);
 107                                 }
 108                         }
 109
 110                 }
 111 */
 112                 if (untar_function & (extract_verbose_extract | extract_contents)) {
 113                         printf("%s\n", raw_tar_header.name);
 114                 }
 115
 116                 /* extract files */
 117                 if (base_path != NULL) {
 118                         dir = xmalloc(strlen(raw_tar_header.name) + strlen(base_path) + 2);
 119                         sprintf(dir, "%s/%s", base_path, raw_tar_header.name);
 120                         create_path(dir, 0777);
 121                 }
 122                 switch (raw_tar_header.typeflag ) {
 123                         case '0':
 124                         case '\0':
 125                                 /* If the name ends in a '/' then assume it is
 126                                  * supposed to be a directory, and fall through
 127                                  */
 128                                 if (raw_tar_header.name[strlen(raw_tar_header.name)-1] != '/') {
 129                                         switch (untar_function) {
 130                                                 case (extract_extract): {
 131                                                                 FILE *dst_file = wfopen(dir, "w");
 132                                                                 copy_file_chunk(src_tar_file, dst_file, size);
 133                                                                 fclose(dst_file);
 134                                                         }
 135                                                         break;
 136                                                 default: {
 137                                                                 int remaining = size;
 138                                                                 while (remaining-- > 0) {
 139                                                                         fgetc(src_tar_file);
 140                                                                 }
 141                                                         }
 142                                         }
 143                                         uncompressed_count += size;
 144                                         break;
 145                                 }
 146                         case '5':
 147                                 if (untar_function & (extract_extract | extract_verbose_extract)) {
 148                                         if (create_path(dir, mode) != TRUE) {
 149                                                 free(dir);
 150                                                 perror_msg("%s: Cannot mkdir", raw_tar_header.name);
 151                                                 return(EXIT_FAILURE);
 152                                         }
 153                                 }
 154                                 break;
 155                         case '1':
 156                                 if (untar_function & extract_extract) {
 157                                         if (link(raw_tar_header.linkname, raw_tar_header.name) < 0) {
 158                                                 free(dir);
 159                                                 perror_msg("%s: Cannot create hard link to '%s'", raw_tar_header.name, raw_tar_header.linkname);
 160                                                 return(EXIT_FAILURE);
 161                                         }
 162                                 }
 163                                 break;
 164                         case '2':
 165                                 if (untar_function & extract_extract) {
 166                                         if (symlink(raw_tar_header.linkname, raw_tar_header.name) < 0) {
 167                                                 free(dir);
 168                                                 perror_msg("%s: Cannot create symlink to '%s'", raw_tar_header.name, raw_tar_header.linkname);
 169                                                 return(EXIT_FAILURE);
 170                                         }
 171                                 }
 172                                 break;
 173                         case '3':
 174                         case '4':
 175                         case '6':
 176 //                              if (tarExtractSpecial( &header, extractFlag, tostdoutFlag)==FALSE)
 177 //                                      errorFlag=TRUE;
 178 //                              break;
 179                         default:
 180                                 error_msg("Unknown file type '%c' in tar file", raw_tar_header.typeflag);
 181                                 free(dir);
 182                                 return(EXIT_FAILURE);
 183                 }
 184 //              free(dir);
 185         }
 186         return(EXIT_SUCCESS);
 187 }