archival/libunarchive/unarchive.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 <errno.h>
  18 #include <fnmatch.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <utime.h>
  24 #include "unarchive.h"
  25 #include "libbb.h"
  26
  27 /* Extract the data postioned at src_stream to either filesystem, stdout or
  28  * buffer depending on the value of 'function' which is defined in libbb.h
  29  *
  30  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  31  *
  32  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  33  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  34  * 'dpkg.' as their prefix
  35  *
  36  * For this reason if prefix does point to a dir then it must end with a
  37  * trailing '/' or else the last dir will be assumed to be the file prefix
  38  */
  39 char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
  40  const int function, const char *prefix)
  41 {
  42         FILE *dst_stream = NULL;
  43         char *full_name = NULL;
  44         char *buffer = NULL;
  45         struct utimbuf t;
  46
  47         /* prefix doesnt have to be a proper path it may prepend
  48          * the filename as well */
  49         if (prefix != NULL) {
  50                 /* strip leading '/' in filename to extract as prefix may not be dir */
  51                 /* Cant use concat_path_file here as prefix might not be a directory */
  52                 char *path = file_entry->name;
  53                 if (strncmp("./", path, 2) == 0) {
  54                         path += 2;
  55                         if (strlen(path) == 0) {
  56                                 return(NULL);
  57                         }
  58                 }
  59                 full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
  60                 strcpy(full_name, prefix);
  61                 strcat(full_name, path);
  62         } else {
  63                 full_name = file_entry->name;
  64         }
  65         if (function & extract_to_stdout) {
  66                 if (S_ISREG(file_entry->mode)) {
  67                         copy_file_chunk(src_stream, out_stream, file_entry->size);
  68                         archive_offset += file_entry->size;
  69                 }
  70         }
  71         else if (function & extract_one_to_buffer) {
  72                 if (S_ISREG(file_entry->mode)) {
  73                         buffer = (char *) xmalloc(file_entry->size + 1);
  74                         fread(buffer, 1, file_entry->size, src_stream);
  75                         buffer[file_entry->size] = '\0';
  76                         archive_offset += file_entry->size;
  77                         return(buffer);
  78                 }
  79         }
  80         else if (function & extract_all_to_fs) {
  81                 struct stat oldfile;
  82                 int stat_res;
  83                 stat_res = lstat (full_name, &oldfile);
  84                 if (stat_res == 0) { /* The file already exists */
  85                         if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
  86                                 if (!S_ISDIR(oldfile.st_mode)) {
  87                                         unlink(full_name); /* Directories might not be empty etc */
  88                                 }
  89                         } else {
  90                                 if ((function & extract_quiet) != extract_quiet) {
  91                                         error_msg("%s not created: newer or same age file exists", file_entry->name);
  92                                 }
  93                                 seek_sub_file(src_stream, file_entry->size);
  94                                 return (NULL);
  95                         }
  96                 }
  97                 if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
  98                         char *buf, *parent;
  99                         buf = xstrdup(full_name);
 100                         parent = dirname(buf);
 101                         if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
 102                                 if ((function & extract_quiet) != extract_quiet) {
 103                                         error_msg("couldn't create leading directories");
 104                                 }
 105                         }
 106                         free (buf);
 107                 }
 108                 switch(file_entry->mode & S_IFMT) {
 109                         case S_IFREG:
 110                                 if (file_entry->link_name) { /* Found a cpio hard link */
 111                                         if (link(file_entry->link_name, full_name) != 0) {
 112                                                 if ((function & extract_quiet) != extract_quiet) {
 113                                                         perror_msg("Cannot link from %s to '%s'",
 114                                                                 file_entry->name, file_entry->link_name);
 115                                                 }
 116                                         }
 117                                 } else {
 118                                         if ((dst_stream = wfopen(full_name, "w")) == NULL) {
 119                                                 seek_sub_file(src_stream, file_entry->size);
 120                                                 return NULL;
 121                                         }
 122                                         archive_offset += file_entry->size;
 123                                         copy_file_chunk(src_stream, dst_stream, file_entry->size);
 124                                         fclose(dst_stream);
 125                                 }
 126                                 break;
 127                         case S_IFDIR:
 128                                 if (stat_res != 0) {
 129                                         if (mkdir(full_name, file_entry->mode) < 0) {
 130                                                 if ((function & extract_quiet) != extract_quiet) {
 131                                                         perror_msg("extract_archive: %s", full_name);
 132                                                 }
 133                                         }
 134                                 }
 135                                 break;
 136                         case S_IFLNK:
 137                                 if (symlink(file_entry->link_name, full_name) < 0) {
 138                                         if ((function & extract_quiet) != extract_quiet) {
 139                                                 perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
 140                                         }
 141                                         return NULL;
 142                                 }
 143                                 break;
 144                         case S_IFSOCK:
 145                         case S_IFBLK:
 146                         case S_IFCHR:
 147                         case S_IFIFO:
 148                                 if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
 149                                         if ((function & extract_quiet) != extract_quiet) {
 150                                                 perror_msg("Cannot create node %s", file_entry->name);
 151                                         }
 152                                         return NULL;
 153                                 }
 154                                 break;
 155                 }
 156
 157                 /* Changing a symlink's properties normally changes the properties of the
 158                  * file pointed to, so dont try and change the date or mode, lchown does
 159                  * does the right thing, but isnt available in older versions of libc */
 160                 if (S_ISLNK(file_entry->mode)) {
 161 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 162                         lchown(full_name, file_entry->uid, file_entry->gid);
 163 #endif
 164                 } else {
 165                         if (function & extract_preserve_date) {
 166                                 t.actime = file_entry->mtime;
 167                                 t.modtime = file_entry->mtime;
 168                                 utime(full_name, &t);
 169                         }
 170                         chmod(full_name, file_entry->mode);
 171                         chown(full_name, file_entry->uid, file_entry->gid);
 172                 }
 173         } else {
 174                 /* If we arent extracting data we have to skip it,
 175                  * if data size is 0 then then just do it anyway
 176                  * (saves testing for it) */
 177                 seek_sub_file(src_stream, file_entry->size);
 178         }
 179
 180         /* extract_list and extract_verbose_list can be used in conjunction
 181          * with one of the above four extraction functions, so do this seperately */
 182         if (function & extract_verbose_list) {
 183                 fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
 184                         file_entry->uid, file_entry->gid,
 185                         (int) file_entry->size, time_string(file_entry->mtime));
 186         }
 187         if ((function & extract_list) || (function & extract_verbose_list)){
 188                 /* fputs doesnt add a trailing \n, so use fprintf */
 189                 fprintf(out_stream, "%s\n", full_name);
 190         }
 191
 192         free(full_name);
 193
 194         return(NULL); /* Maybe we should say if failed */
 195 }
 196
 197 char *unarchive(FILE *src_stream, FILE *out_stream, file_header_t *(*get_headers)(FILE *),
 198         const int extract_function, const char *prefix, char **include_name, char **exclude_name)
 199 {
 200         file_header_t *file_entry;
 201         int extract_flag = TRUE;
 202         int i;
 203         char *buffer = NULL;
 204
 205         archive_offset = 0;
 206         while ((file_entry = get_headers(src_stream)) != NULL) {
 207
 208                 if (include_name != NULL) {
 209                         extract_flag = FALSE;
 210                         for(i = 0; include_name[i] != 0; i++) {
 211                                 if (fnmatch(include_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
 212                                         extract_flag = TRUE;
 213                                         break;
 214                                 }
 215                         }
 216                 } else {
 217                         extract_flag = TRUE;
 218                 }
 219
 220                 /* If the file entry is in the exclude list dont extract it */
 221                 if (exclude_name != NULL) {
 222                         for(i = 0; exclude_name[i] != 0; i++) {
 223                                 if (fnmatch(exclude_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
 224                                         extract_flag = FALSE;
 225                                         break;
 226                                 }
 227                         }
 228                 }
 229
 230                 if (extract_flag) {
 231                         buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
 232                 } else {
 233                         /* seek past the data entry */
 234                         seek_sub_file(src_stream, file_entry->size);
 235                 }
 236                 free(file_entry->name);
 237                 free(file_entry->link_name);
 238                 free(file_entry);
 239         }
 240         return(buffer);
 241 }