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 <sys/wait.h>
  25 #include <signal.h>
  26 #include "unarchive.h"
  27 #include "busybox.h"
  28
  29 /* Extract the data postioned at src_stream to either filesystem, stdout or
  30  * buffer depending on the value of 'function' which is defined in libbb.h
  31  *
  32  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  33  *
  34  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  35  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  36  * 'dpkg.' as their prefix
  37  *
  38  * For this reason if prefix does point to a dir then it must end with a
  39  * trailing '/' or else the last dir will be assumed to be the file prefix
  40  */
  41 char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
  42  const int function, const char *prefix)
  43 {
  44         FILE *dst_stream = NULL;
  45         char *full_name = NULL;
  46         char *buffer = NULL;
  47         struct utimbuf t;
  48
  49         /* prefix doesnt have to be a proper path it may prepend
  50          * the filename as well */
  51         if (prefix != NULL) {
  52                 /* strip leading '/' in filename to extract as prefix may not be dir */
  53                 /* Cant use concat_path_file here as prefix might not be a directory */
  54                 char *path = file_entry->name;
  55                 if (strncmp("./", path, 2) == 0) {
  56                         path += 2;
  57                         if (strlen(path) == 0) {
  58                                 return(NULL);
  59                         }
  60                 }
  61                 full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
  62                 strcpy(full_name, prefix);
  63                 strcat(full_name, path);
  64         } else {
  65                 full_name = file_entry->name;
  66         }
  67         if (function & extract_to_stdout) {
  68                 if (S_ISREG(file_entry->mode)) {
  69                         copy_file_chunk(src_stream, out_stream, file_entry->size);
  70                         archive_offset += file_entry->size;
  71                 }
  72         }
  73         else if (function & extract_one_to_buffer) {
  74                 if (S_ISREG(file_entry->mode)) {
  75                         buffer = (char *) xmalloc(file_entry->size + 1);
  76                         fread(buffer, 1, file_entry->size, src_stream);
  77                         buffer[file_entry->size] = '\0';
  78                         archive_offset += file_entry->size;
  79                         return(buffer);
  80                 }
  81         }
  82         else if (function & extract_all_to_fs) {
  83                 struct stat oldfile;
  84                 int stat_res;
  85                 stat_res = lstat (full_name, &oldfile);
  86                 if (stat_res == 0) { /* The file already exists */
  87                         if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
  88                                 if (!S_ISDIR(oldfile.st_mode)) {
  89                                         unlink(full_name); /* Directories might not be empty etc */
  90                                 }
  91                         } else {
  92                                 if ((function & extract_quiet) != extract_quiet) {
  93                                         error_msg("%s not created: newer or same age file exists", file_entry->name);
  94                                 }
  95                                 seek_sub_file(src_stream, file_entry->size);
  96                                 return (NULL);
  97                         }
  98                 }
  99                 if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
 100                         char *buf, *parent;
 101                         buf = xstrdup(full_name);
 102                         parent = dirname(buf);
 103                         if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
 104                                 if ((function & extract_quiet) != extract_quiet) {
 105                                         error_msg("couldn't create leading directories");
 106                                 }
 107                         }
 108                         free (buf);
 109                 }
 110                 switch(file_entry->mode & S_IFMT) {
 111                         case S_IFREG:
 112                                 if (file_entry->link_name) { /* Found a cpio hard link */
 113                                         if (link(file_entry->link_name, full_name) != 0) {
 114                                                 if ((function & extract_quiet) != extract_quiet) {
 115                                                         perror_msg("Cannot link from %s to '%s'",
 116                                                                 file_entry->name, file_entry->link_name);
 117                                                 }
 118                                         }
 119                                 } else {
 120                                         if ((dst_stream = wfopen(full_name, "w")) == NULL) {
 121                                                 seek_sub_file(src_stream, file_entry->size);
 122                                                 return NULL;
 123                                         }
 124                                         archive_offset += file_entry->size;
 125                                         if (file_entry->extract_func) file_entry->extract_func(src_stream, dst_stream);
 126                                         else copy_file_chunk(src_stream, dst_stream, file_entry->size);
 127                                         fclose(dst_stream);
 128                                 }
 129                                 break;
 130                         case S_IFDIR:
 131                                 if (stat_res != 0) {
 132                                         if (mkdir(full_name, file_entry->mode) < 0) {
 133                                                 if ((function & extract_quiet) != extract_quiet) {
 134                                                         perror_msg("extract_archive: %s", full_name);
 135                                                 }
 136                                         }
 137                                 }
 138                                 break;
 139                         case S_IFLNK:
 140                                 if (symlink(file_entry->link_name, full_name) < 0) {
 141                                         if ((function & extract_quiet) != extract_quiet) {
 142                                                 perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
 143                                         }
 144                                         return NULL;
 145                                 }
 146                                 break;
 147                         case S_IFSOCK:
 148                         case S_IFBLK:
 149                         case S_IFCHR:
 150                         case S_IFIFO:
 151                                 if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
 152                                         if ((function & extract_quiet) != extract_quiet) {
 153                                                 perror_msg("Cannot create node %s", file_entry->name);
 154                                         }
 155                                         return NULL;
 156                                 }
 157                                 break;
 158                 }
 159
 160                 /* Changing a symlink's properties normally changes the properties of the
 161                  * file pointed to, so dont try and change the date or mode, lchown does
 162                  * does the right thing, but isnt available in older versions of libc */
 163                 if (S_ISLNK(file_entry->mode)) {
 164 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 165                         lchown(full_name, file_entry->uid, file_entry->gid);
 166 #endif
 167                 } else {
 168                         if (function & extract_preserve_date) {
 169                                 t.actime = file_entry->mtime;
 170                                 t.modtime = file_entry->mtime;
 171                                 utime(full_name, &t);
 172                         }
 173                         chmod(full_name, file_entry->mode);
 174                         chown(full_name, file_entry->uid, file_entry->gid);
 175                 }
 176         } else {
 177                 /* If we arent extracting data we have to skip it,
 178                  * if data size is 0 then then just do it anyway
 179                  * (saves testing for it) */
 180                 seek_sub_file(src_stream, file_entry->size);
 181         }
 182
 183         /* extract_list and extract_verbose_list can be used in conjunction
 184          * with one of the above four extraction functions, so do this seperately */
 185         if (function & extract_verbose_list) {
 186                 fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
 187                         file_entry->uid, file_entry->gid,
 188                         (int) file_entry->size, time_string(file_entry->mtime));
 189         }
 190         if ((function & extract_list) || (function & extract_verbose_list)){
 191                 /* fputs doesnt add a trailing \n, so use fprintf */
 192                 fprintf(out_stream, "%s\n", full_name);
 193         }
 194
 195         if (prefix != NULL) {
 196           free(full_name);
 197         }
 198
 199         return(NULL); /* Maybe we should say if failed */
 200 }
 201
 202 char *unarchive(FILE *src_stream, FILE *out_stream, file_header_t *(*get_headers)(FILE *),
 203         const int extract_function, const char *prefix, char **include_name, char **exclude_name)
 204 {
 205         file_header_t *file_entry;
 206         int extract_flag = TRUE;
 207         int i;
 208         char *buffer = NULL;
 209 #ifdef CONFIG_FEATURE_UNARCHIVE_TAPE
 210         int pid, tape_pipe[2];
 211
 212         if (pipe(tape_pipe) != 0) error_msg_and_die("Can't create pipe\n");
 213         if ((pid = fork()) == -1) error_msg_and_die("Fork failed\n");
 214         if (pid==0) { /* child process */
 215             close(tape_pipe[0]); /* We don't wan't to read from the pipe */
 216             copyfd(fileno(src_stream), tape_pipe[1]);
 217             close(tape_pipe[1]); /* Send EOF */
 218             exit(0);
 219             /* notreached */
 220         }
 221         close(tape_pipe[1]); /* Don't want to write down the pipe */
 222         fclose(src_stream);
 223         src_stream = fdopen(tape_pipe[0], "r");
 224 #endif
 225         archive_offset = 0;
 226         while ((file_entry = get_headers(src_stream)) != NULL) {
 227
 228                 if (include_name != NULL) {
 229                         extract_flag = FALSE;
 230                         for(i = 0; include_name[i] != 0; i++) {
 231                                 if (fnmatch(include_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
 232                                         extract_flag = TRUE;
 233                                         break;
 234                                 }
 235                         }
 236                 } else {
 237                         extract_flag = TRUE;
 238                 }
 239
 240                 /* If the file entry is in the exclude list dont extract it */
 241                 if (exclude_name != NULL) {
 242                         for(i = 0; exclude_name[i] != 0; i++) {
 243                                 if (fnmatch(exclude_name[i], file_entry->name, FNM_LEADING_DIR) == 0) {
 244                                         extract_flag = FALSE;
 245                                         break;
 246                                 }
 247                         }
 248                 }
 249
 250                 if (extract_flag) {
 251                         buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
 252                 } else {
 253                         /* seek past the data entry */
 254                         seek_sub_file(src_stream, file_entry->size);
 255                 }
 256                 free(file_entry->name);
 257                 free(file_entry->link_name);
 258                 free(file_entry);
 259         }
 260 #ifdef CONFIG_FEATURE_UNARCHIVE_TAPE
 261         kill(pid, SIGTERM);
 262         waitpid(pid, NULL, 0);
 263 #endif
 264         return(buffer);
 265 }