root/ext/zip/lib/zip_source_zip_new.c

DEFINITIONS

1. _zip_source_zip_new

   1 /*
   2   zip_source_zip_new.c -- prepare data structures for zip_fopen/zip_source_zip
   3   Copyright (C) 2012-2015 Dieter Baron and Thomas Klausner
   4 
   5   This file is part of libzip, a library to manipulate ZIP archives.
   6   The authors can be contacted at <libzip@nih.at>
   7 
   8   Redistribution and use in source and binary forms, with or without
   9   modification, are permitted provided that the following conditions
  10   are met:
  11   1. Redistributions of source code must retain the above copyright
  12      notice, this list of conditions and the following disclaimer.
  13   2. Redistributions in binary form must reproduce the above copyright
  14      notice, this list of conditions and the following disclaimer in
  15      the documentation and/or other materials provided with the
  16      distribution.
  17   3. The names of the authors may not be used to endorse or promote
  18      products derived from this software without specific prior
  19      written permission.
  20  
  21   THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
  22   OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24   ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  25   DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  27   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  29   IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  30   OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  31   IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32 */
  33 
  34 
  35 #include <stdlib.h>
  36 
  37 #include "zipint.h"
  38 
  39 
  40 zip_source_t *
  41 _zip_source_zip_new(zip_t *za, zip_t *srcza, zip_uint64_t srcidx, zip_flags_t flags, zip_uint64_t start, zip_uint64_t len, const char *password)
  42 {
  43     zip_compression_implementation comp_impl;
  44     zip_encryption_implementation enc_impl;
  45     zip_source_t *src, *s2;
  46     zip_uint64_t offset;
  47     struct zip_stat st;
  48 
  49     if (za == NULL)
  50         return NULL;
  51 
  52     if (srcza == NULL || srcidx >= srcza->nentry) {
  53         zip_error_set(&za->error, ZIP_ER_INVAL, 0);
  54         return NULL;
  55     }
  56 
  57     if ((flags & ZIP_FL_UNCHANGED) == 0
  58         && (ZIP_ENTRY_DATA_CHANGED(srcza->entry+srcidx) || srcza->entry[srcidx].deleted)) {
  59         zip_error_set(&za->error, ZIP_ER_CHANGED, 0);
  60         return NULL;
  61     }
  62 
  63     if (zip_stat_index(srcza, srcidx, flags|ZIP_FL_UNCHANGED, &st) < 0) {
  64         zip_error_set(&za->error, ZIP_ER_INTERNAL, 0);
  65         return NULL;
  66     }
  67 
  68     if (flags & ZIP_FL_ENCRYPTED)
  69         flags |= ZIP_FL_COMPRESSED;
  70 
  71     if ((start > 0 || len > 0) && (flags & ZIP_FL_COMPRESSED)) {
  72         zip_error_set(&za->error, ZIP_ER_INVAL, 0);
  73         return NULL;
  74     }
  75 
  76     /* overflow or past end of file */
  77     if ((start > 0 || len > 0) && (start+len < start || start+len > st.size)) {
  78         zip_error_set(&za->error, ZIP_ER_INVAL, 0);
  79         return NULL;
  80     }
  81 
  82     enc_impl = NULL;
  83     if (((flags & ZIP_FL_ENCRYPTED) == 0) && (st.encryption_method != ZIP_EM_NONE)) {
  84         if (password == NULL) {
  85             zip_error_set(&za->error, ZIP_ER_NOPASSWD, 0);
  86             return NULL;
  87         }
  88         if ((enc_impl=_zip_get_encryption_implementation(st.encryption_method)) == NULL) {
  89             zip_error_set(&za->error, ZIP_ER_ENCRNOTSUPP, 0);
  90             return NULL;
  91         }
  92     }
  93 
  94     comp_impl = NULL;
  95     if ((flags & ZIP_FL_COMPRESSED) == 0) {
  96         if (st.comp_method != ZIP_CM_STORE) {
  97             if ((comp_impl=_zip_get_compression_implementation(st.comp_method)) == NULL) {
  98                 zip_error_set(&za->error, ZIP_ER_COMPNOTSUPP, 0);
  99                 return NULL;
 100             }
 101         }
 102     }
 103 
 104     if ((offset=_zip_file_get_offset(srcza, srcidx, &za->error)) == 0)
 105         return NULL;
 106 
 107     if (st.comp_size == 0) {
 108         return zip_source_buffer(za, NULL, 0, 0);
 109     }
 110 
 111     if (start+len > 0 && enc_impl == NULL && comp_impl == NULL) {
 112         struct zip_stat st2;
 113         
 114         st2.size = len ? len : st.size-start;
 115         st2.comp_size = st2.size;
 116         st2.comp_method = ZIP_CM_STORE;
 117         st2.mtime = st.mtime;
 118         st2.valid = ZIP_STAT_SIZE|ZIP_STAT_COMP_SIZE|ZIP_STAT_COMP_METHOD|ZIP_STAT_MTIME;
 119         
 120         if ((src = _zip_source_window_new(srcza->src, offset+start, st2.size, &st2, &za->error)) == NULL) {
 121             return NULL;
 122         }
 123     }
 124     else {
 125         if ((src = _zip_source_window_new(srcza->src, offset, st.comp_size, &st, &za->error)) == NULL) {
 126             return NULL;
 127         }
 128     }
 129         
 130     if (_zip_source_set_source_archive(src, srcza) < 0) {
 131         zip_source_free(src);
 132         return NULL;
 133     }
 134 
 135     /* creating a layered source calls zip_keep() on the lower layer, so we free it */
 136         
 137     if (enc_impl) {
 138         s2 = enc_impl(za, src, st.encryption_method, 0, password);
 139         zip_source_free(src);
 140         if (s2 == NULL) {
 141             return NULL;
 142         }
 143         src = s2;
 144     }
 145     if (comp_impl) {
 146         s2 = comp_impl(za, src, st.comp_method, 0);
 147         zip_source_free(src);
 148         if (s2 == NULL) {
 149             return NULL;
 150         }
 151         src = s2;
 152     }
 153     if (((flags & ZIP_FL_COMPRESSED) == 0 || st.comp_method == ZIP_CM_STORE) && (len == 0 || len == st.comp_size)) {
 154         /* when reading the whole file, check for CRC errors */
 155         s2 = zip_source_crc(za, src, 1);
 156         zip_source_free(src);
 157         if (s2 == NULL) {
 158             return NULL;
 159         }
 160         src = s2;
 161     }
 162 
 163     if (start+len > 0 && (comp_impl || enc_impl)) {
 164         s2 = zip_source_window(za, src, start, len ? len : st.size-start);
 165         zip_source_free(src);
 166         if (s2 == NULL) {
 167             return NULL;
 168         }
 169         src = s2;
 170     }
 171 
 172     return src;
 173 }