1 /*
2 zip_source_crc.c -- pass-through source that calculates CRC32 and size
3 Copyright (C) 2009 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
36 #include <stdlib.h>
37 #include <string.h>
38
39 #include "zipint.h"
40
41 struct crc_context {
42 int eof;
43 int validate;
44 int e[2];
45 zip_uint64_t size;
46 zip_uint32_t crc;
47 };
48
49 static zip_int64_t crc_read(struct zip_source *, void *, void *
50 , zip_uint64_t, enum zip_source_cmd);
51
52
53
54 struct zip_source *
55 zip_source_crc(struct zip *za, struct zip_source *src, int validate)
56 {
57 struct crc_context *ctx;
58
59 if (src == NULL) {
60 _zip_error_set(&za->error, ZIP_ER_INVAL, 0);
61 return NULL;
62 }
63
64 if ((ctx=(struct crc_context *)malloc(sizeof(*ctx))) == NULL) {
65 _zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
66 return NULL;
67 }
68
69 ctx->eof = 0;
70 ctx->validate = validate;
71 ctx->e[0] = ctx->e[1] = 0;
72 ctx->size = 0;
73 ctx->crc = 0;
74
75 return zip_source_layered(za, src, crc_read, ctx);
76 }
77
78
79
80 static zip_int64_t
81 crc_read(struct zip_source *src, void *_ctx, void *data,
82 zip_uint64_t len, enum zip_source_cmd cmd)
83 {
84 struct crc_context *ctx;
85 zip_int64_t n;
86
87 ctx = (struct crc_context *)_ctx;
88
89 switch (cmd) {
90 case ZIP_SOURCE_OPEN:
91 ctx->eof = 0;
92 ctx->crc = (zip_uint32_t)crc32(0, NULL, 0);
93 ctx->size = 0;
94
95 return 0;
96
97 case ZIP_SOURCE_READ:
98 if (ctx->eof || len == 0)
99 return 0;
100
101 if ((n=zip_source_read(src, data, len)) < 0)
102 return ZIP_SOURCE_ERR_LOWER;
103
104 if (n == 0) {
105 ctx->eof = 1;
106 if (ctx->validate) {
107 struct zip_stat st;
108
109 if (zip_source_stat(src, &st) < 0)
110 return ZIP_SOURCE_ERR_LOWER;
111
112 if ((st.valid & ZIP_STAT_CRC) && st.crc != ctx->crc) {
113 ctx->e[0] = ZIP_ER_CRC;
114 ctx->e[1] = 0;
115
116 return -1;
117 }
118 if ((st.valid & ZIP_STAT_SIZE) && st.size != ctx->size) {
119 ctx->e[0] = ZIP_ER_INCONS;
120 ctx->e[1] = 0;
121
122 return -1;
123 }
124 }
125 }
126 else {
127 ctx->size += (zip_uint64_t)n;
128 ctx->crc = (zip_uint32_t)crc32(ctx->crc, (const Bytef *)data, (uInt)n); /* TODO: check for overflow, use multiple crc calls if needed */
129 }
130 return n;
131
132 case ZIP_SOURCE_CLOSE:
133 return 0;
134
135 case ZIP_SOURCE_STAT:
136 {
137 struct zip_stat *st;
138
139 st = (struct zip_stat *)data;
140
141 if (ctx->eof) {
142 /* TODO: Set comp_size, comp_method, encryption_method?
143 After all, this only works for uncompressed data. */
144 st->size = ctx->size;
145 st->crc = ctx->crc;
146 st->comp_size = ctx->size;
147 st->comp_method = ZIP_CM_STORE;
148 st->encryption_method = ZIP_EM_NONE;
149 st->valid |= ZIP_STAT_SIZE|ZIP_STAT_CRC|ZIP_STAT_COMP_SIZE|ZIP_STAT_COMP_METHOD|ZIP_STAT_ENCRYPTION_METHOD;;
150 }
151 }
152 return 0;
153
154 case ZIP_SOURCE_ERROR:
155 memcpy(data, ctx->e, sizeof(ctx->e));
156 return 0;
157
158 case ZIP_SOURCE_FREE:
159 free(ctx);
160 return 0;
161
162 default:
163 return -1;
164 }
165
166 }