libbb/extract_archive.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 <stdlib.h>
  18 #include <string.h>
  19 #include <time.h>
  20 #include <unistd.h>
  21 #include <utime.h>
  22 #include "libbb.h"
  23
  24 /* Extract files in the linear linked list 'extract_headers' to either
  25  * filesystem, stdout or buffer depending on the value of 'function' which is
  26  * described in extract_files.h
  27  *
  28  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  29  *
  30  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  31  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  32  * 'dpkg.' as their prefix
  33  *
  34  * For this reason if prefix does point to a dir then it must end with a
  35  * trailing '/' or else the last dir will be assumed to be the file prefix
  36  */
  37
  38 char *extract_archive(FILE *src_stream, FILE *out_stream, file_headers_t *extract_headers, int function, const char *prefix)
  39 {
  40         FILE *dst_stream = NULL;
  41         char *full_name = NULL;
  42         char *buffer = NULL;
  43         size_t uncompressed_count = 0;
  44         struct utimbuf t;
  45
  46         /* find files to extract or display */
  47         while (extract_headers != NULL) {
  48                 /* prefix doesnt have to be a proper path it may prepend
  49                  * the filename as well */
  50                 if (prefix != NULL) {
  51                         /* strip leading '/' in filename to extract as prefix may not be dir */
  52                         char *tmp_str = strchr(extract_headers->name, '/');
  53                         if (tmp_str == NULL) {
  54                                 tmp_str = extract_headers->name;
  55                         } else {
  56                                 tmp_str++;
  57                         }
  58                         /* Cant use concat_path_file here as prefix might not be a directory */
  59                         full_name = xmalloc(strlen(prefix) + strlen(tmp_str) + 1);
  60                         strcpy(full_name, prefix);
  61                         strcat(full_name, tmp_str);
  62                 } else {
  63                         full_name = extract_headers->name;
  64                 }
  65
  66                 /* Seek to start of file, have to use fgetc as src_stream may be a pipe
  67                  * you cant [lf]seek on pipes */
  68                 while (uncompressed_count < extract_headers->offset) {
  69                         fgetc(src_stream);
  70                         uncompressed_count++;
  71                 }
  72
  73                 if (S_ISREG(extract_headers->mode)) {
  74                         if (function & extract_to_stdout) {
  75                                 copy_file_chunk(src_stream, out_stream, extract_headers->size);
  76                                 uncompressed_count += extract_headers->size;
  77                         }
  78                         else if (function & extract_all_to_fs) {
  79                                 dst_stream = wfopen(full_name, "w");
  80                                 copy_file_chunk(src_stream, dst_stream, extract_headers->size);
  81                                 uncompressed_count += extract_headers->size;
  82                                 fclose(dst_stream);
  83                         }
  84                         else if (function & extract_one_to_buffer) {
  85                                 buffer = (char *) xmalloc(extract_headers->size + 1);
  86                                 fread(buffer, 1, extract_headers->size, src_stream);
  87                                 break;
  88                         }
  89                 }
  90 #if defined BB_DPKG | defined BB_DPKG_DEB
  91                 else if (S_ISDIR(extract_headers->mode)) {
  92                         if (function & extract_all_to_fs) {
  93                                 if (create_path(full_name, extract_headers->mode) == FALSE) {
  94                                         perror_msg("Cannot mkdir %s", extract_headers->name);
  95                                         return NULL;
  96                                 }
  97                         }
  98                 }
  99                 else if (S_ISLNK(extract_headers->mode)) {
 100                         if (function & extract_all_to_fs) {
 101                                 if (symlink(extract_headers->link_name, full_name) < 0) {
 102                                         perror_msg("Cannot create hard link from %s to '%s'", extract_headers->name, extract_headers->link_name);
 103                                         return NULL;
 104                                 }
 105                         }
 106                 }
 107 #endif
 108                 if (function & extract_verbose_list) {
 109                         fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(extract_headers->mode),
 110                                 extract_headers->uid, extract_headers->gid,
 111                                 (int) extract_headers->size, time_string(extract_headers->mtime));
 112                 }
 113
 114                 if ((function & extract_list) || (function & extract_verbose_list)){
 115                         /* fputs doesnt add a trailing \n, so use fprintf */
 116                         fprintf(out_stream, "%s\n", extract_headers->name);
 117                 }
 118
 119                 if (function & extract_preserve_date) {
 120                         t.actime = extract_headers->mtime;
 121                         t.modtime = extract_headers->mtime;
 122                         utime(full_name, &t);
 123                 }
 124                 chmod(full_name, extract_headers->mode);
 125                 free(full_name);
 126
 127                 extract_headers = extract_headers->next;
 128         }
 129
 130         return(buffer);
 131 }
 132