/src/libzip/lib/zip_source_window.c

Source
/*
  zip_source_window.c -- return part of lower source
  Copyright (C) 2012-2025 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.
  The authors can be contacted at <info@libzip.org>

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.
  3. The names of the authors may not be used to endorse or promote
     products derived from this software without specific prior
     written permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include "zipint.h"

#include <stdlib.h>
#include <string.h>

struct window {
    zip_uint64_t start; /* where in file we start reading */
    zip_uint64_t end;   /* where in file we stop reading */
    bool end_valid;     /* whether end is set, otherwise read until EOF */

    /* if not NULL, read file data for this file */
    zip_t *source_archive;
    zip_uint64_t source_index;

    zip_uint64_t offset; /* offset in src for next read */

    zip_stat_t stat;
    zip_uint64_t stat_invalid;
    zip_file_attributes_t attributes;
    zip_dostime_t dostime;
    bool dostime_valid;
    zip_error_t error;
    zip_int64_t supports;
    bool needs_seek;
};

typedef struct window window_t;

static window_t *window_new(void);
static void window_free(window_t *ctx);

static zip_int64_t window_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);


ZIP_EXTERN zip_source_t *zip_source_window_create(zip_source_t *src, zip_uint64_t start, zip_int64_t len, zip_error_t *error) {
    return _zip_source_window_new(src, start, len, NULL, 0, NULL, NULL, NULL, 0, false, error);
}


zip_source_t *_zip_source_window_new(zip_source_t *src, zip_uint64_t start, zip_int64_t length, zip_stat_t *st, zip_uint64_t st_invalid, zip_file_attributes_t *attributes, zip_dostime_t *dostime, zip_t *source_archive, zip_uint64_t source_index, bool take_ownership, zip_error_t *error) {
    zip_source_t *window_source;
    struct window *ctx;
    zip_stat_t lower_st;

    if (src == NULL || length < -1 || (source_archive == NULL && source_index != 0)) {
        zip_error_set(error, ZIP_ER_INVAL, 0);
        return NULL;
    }

    if (length > 0) {
        if (start + (zip_uint64_t)length < start) {
            zip_error_set(error, ZIP_ER_INVAL, 0);
            return NULL;
        }
    }

    zip_stat_init(&lower_st);
    (void)zip_source_stat(src, &lower_st);

    if (lower_st.valid & ZIP_STAT_SIZE) {
        if (start > lower_st.size || (length > 0 && start + (zip_uint64_t)length > lower_st.size)) {
            zip_error_set(error, ZIP_ER_INVAL, 0);
            return NULL;
        }
    }

    if ((ctx = window_new()) == NULL) {
        zip_error_set(error, ZIP_ER_MEMORY, 0);
        return NULL;
    }

    ctx->start = start;
    if (length == -1) {
        ctx->end_valid = false;
    }
    else {
        ctx->end = start + (zip_uint64_t)length;
        ctx->end_valid = true;
    }
    ctx->stat_invalid = st_invalid;
    if (attributes != NULL) {
        (void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
    }
    if (dostime != NULL) {
        ctx->dostime = *dostime;
        ctx->dostime_valid = true;
    }
    ctx->source_archive = source_archive;
    ctx->source_index = source_index;
    ctx->supports = (zip_source_supports(src) & (ZIP_SOURCE_SUPPORTS_SEEKABLE | ZIP_SOURCE_SUPPORTS_REOPEN)) | (zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_GET_DOS_TIME, ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, ZIP_SOURCE_FREE, -1));
    if (ctx->end_valid) {
        ctx->supports |= ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_AT_EOF);
    }
    ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;

    if (st) {
        if (_zip_stat_merge(&ctx->stat, st, error) < 0) {
            window_free(ctx);
            return NULL;
        }
    }

    window_source = zip_source_layered_create(src, window_read, ctx, error);
    if (window_source == NULL) {
        window_free(ctx);
        return NULL;
    }
    if (!take_ownership) {
        zip_source_keep(src);
    }
    return window_source;
}


int _zip_source_set_source_archive(zip_source_t *src, zip_t *za) {
    src->source_archive = za;
    return _zip_register_source(za, src);
}


/* called by zip_discard to avoid operating on file from closed archive */
void _zip_source_invalidate(zip_source_t *src) {
    if (ZIP_SOURCE_IS_OPEN_READING(src)) {
        (void)zip_source_close(src);
    }

    src->source_closed = 1;

    if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {
        zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);
    }
}


static zip_int64_t window_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
    struct window *ctx;
    zip_int64_t ret;
    zip_uint64_t n, i;

    ctx = (struct window *)_ctx;

    switch (cmd) {
    case ZIP_SOURCE_AT_EOF:
        if (ctx->end_valid) {
            return ctx->offset == ctx->end;
        }
        else {
            return zip_source_pass_to_lower_layer(src, data, len, cmd);
        }

    case ZIP_SOURCE_CLOSE:
        return 0;

    case ZIP_SOURCE_ERROR:
        return zip_error_to_data(&ctx->error, data, len);

    case ZIP_SOURCE_FREE:
        window_free(ctx);
        return 0;

    case ZIP_SOURCE_OPEN:
        if (ctx->source_archive) {
            zip_uint64_t offset;

            if ((offset = _zip_file_get_offset(ctx->source_archive, ctx->source_index, &ctx->error)) == 0) {
                return -1;
            }
            if (ctx->end_valid) {
                if (ctx->end + offset < ctx->end) {
                    /* zip archive data claims end of data past zip64 limits */
                    zip_error_set(&ctx->error, ZIP_ER_INCONS, MAKE_DETAIL_WITH_INDEX(ZIP_ER_DETAIL_CDIR_ENTRY_INVALID, ctx->source_index));
                    return -1;
                }
                ctx->end += offset;
            }
            ctx->start += offset;
            ctx->source_archive = NULL;
        }

        if (!ctx->needs_seek) {
            DEFINE_BYTE_ARRAY(b, BUFSIZE);

            if (!byte_array_init(b, BUFSIZE)) {
                zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
                return -1;
            }

            for (n = 0; n < ctx->start; n += (zip_uint64_t)ret) {
                i = (ctx->start - n > BUFSIZE ? BUFSIZE : ctx->start - n);
                if ((ret = zip_source_read(src, b, i)) < 0) {
                    zip_error_set_from_source(&ctx->error, src);
                    byte_array_fini(b);
                    return -1;
                }
                if (ret == 0) {
                    zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
                    byte_array_fini(b);
                    return -1;
                }
            }

            byte_array_fini(b);
        }

        ctx->offset = ctx->start;
        return 0;

    case ZIP_SOURCE_READ:
        if (ctx->end_valid && len > ctx->end - ctx->offset) {
            len = ctx->end - ctx->offset;
        }

        if (len == 0) {
            return 0;
        }

        if (ctx->needs_seek) {
            if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {
                zip_error_set_from_source(&ctx->error, src);
                if (zip_error_code_zip(&ctx->error) == ZIP_ER_INVAL) {
                    /* We validated ctx->offset in ZIP_SEEK. */
                    zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
                }
                return -1;
            }
        }

        if ((ret = zip_source_read(src, data, len)) < 0) {
            zip_error_set_from_source(&ctx->error, src);
            return -1;
        }

        if (ret == 0) {
            if (ctx->end_valid && ctx->offset < ctx->end) {
                zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
                return -1;
            }
        }

        ctx->offset += (zip_uint64_t)ret;
        return ret;

    case ZIP_SOURCE_SEEK: {
        zip_uint64_t length;
        zip_int64_t new_offset;
        zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);

        /*
          If we don't know the length and seek from the end, we seek in the lower source to get the new offset.
        */
        if (!ctx->end_valid && args->whence == SEEK_END) {
            zip_int64_t lower_offset;

            if (zip_source_seek(src, args->offset, args->whence) < 0) {
                zip_error_set_from_source(&ctx->error, src);
                return -1;
            }
            if ((lower_offset = zip_source_tell(src)) < 0) {
                zip_error_set_from_source(&ctx->error, src);
                return -1;
            }
            if ((zip_uint64_t)lower_offset < ctx->start) {
                zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
                return -1;
            }
            ctx->offset = (zip_uint64_t)lower_offset;
            return 0;
        }

        /*
          If we don't know the length, we disable the end check in zip_source_seek_compute_offset by passing in the largest possible value and seek in the lower source to validate the new offset.
        */
        length = ctx->end_valid ? (ctx->end - ctx->start) : ZIP_INT64_MAX;
        new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, length, data, len, &ctx->error);

        if (new_offset < 0) {
            return -1;
        }

        if (new_offset + ctx->start < ctx->start) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }
        new_offset += ctx->start;

        if (!ctx->end_valid) {
            if (zip_source_seek(src, new_offset, SEEK_SET) < 0) {
                zip_error_set_from_source(&ctx->error, src);
                return -1;
            }
        }
        ctx->offset = (zip_uint64_t)new_offset;
        return 0;
    }

    case ZIP_SOURCE_STAT: {
        zip_stat_t *st;

        st = (zip_stat_t *)data;

        if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {
            return -1;
        }

        if (!(ctx->stat.valid & ZIP_STAT_SIZE)) {
            if (ctx->end_valid) {
                st->valid |= ZIP_STAT_SIZE;
                st->size = ctx->end - ctx->start;
            }
            else if (st->valid & ZIP_STAT_SIZE) {
                if (st->size < ctx->start) {
                    st->valid &= ~ZIP_STAT_SIZE;
                }
                else {
                    st->size -= ctx->start;
                }
            }
        }

        st->valid &= ~ctx->stat_invalid;

        return 0;
    }

    case ZIP_SOURCE_GET_FILE_ATTRIBUTES:
        if (len < sizeof(ctx->attributes)) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }

        (void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));
        return sizeof(ctx->attributes);

    case ZIP_SOURCE_GET_DOS_TIME:
        if (len < sizeof(ctx->dostime)) {
            zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
            return -1;
        }
        if (ctx->dostime_valid) {
            (void)memcpy_s(data, sizeof(ctx->dostime), &ctx->dostime, sizeof(ctx->dostime));
            return sizeof(ctx->dostime);
        }
        else {
            return 0;
        }

    case ZIP_SOURCE_SUPPORTS:
        return ctx->supports;

    case ZIP_SOURCE_TELL:
        return (zip_int64_t)(ctx->offset - ctx->start);

    default:
        return zip_source_pass_to_lower_layer(src, data, len, cmd);
    }
}


void _zip_deregister_source(zip_t *za, zip_source_t *src) {
    zip_uint64_t i;

    for (i = 0; i < za->nopen_source; i++) {
        if (za->open_source[i] == src) {
            za->open_source[i] = za->open_source[za->nopen_source - 1];
            za->nopen_source--;
            break;
        }
    }
}


int _zip_register_source(zip_t *za, zip_source_t *src) {
    if (za->nopen_source + 1 >= za->nopen_source_alloc) {
        if (!ZIP_REALLOC(za->open_source, za->nopen_source_alloc, 10, &za->error)) {
            return -1;
        }
    }

    za->open_source[za->nopen_source++] = src;

    return 0;
}

static window_t *window_new(void) {
    window_t *ctx;

    if ((ctx = (window_t *)malloc(sizeof(window_t))) == NULL) {
        return NULL;
    }

    ctx->start = 0;
    ctx->end = 0;
    ctx->end_valid = false;
    ctx->source_archive = NULL;
    ctx->source_index = 0;
    ctx->offset = 0;
    zip_stat_init(&ctx->stat);
    ctx->stat_invalid = 0;
    zip_file_attributes_init(&ctx->attributes);
    ctx->dostime_valid = false;
    zip_error_init(&ctx->error);
    ctx->supports = 0;
    ctx->needs_seek = false;

    return ctx;
}

static void window_free(window_t *ctx) {
    if (ctx == NULL) {
        return;
    }

    zip_error_fini(&ctx->error);
    free(ctx);
}

Coverage Report

Created: 2026-10-28 07:26

Line	Count	Source
1		/*
2		zip_source_window.c -- return part of lower source
3		Copyright (C) 2012-2025 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 <info@libzip.org>
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		#include "zipint.h"
35
36		#include <stdlib.h>
37		#include <string.h>
38
39		struct window {
40		zip_uint64_t start; /* where in file we start reading */
41		zip_uint64_t end; /* where in file we stop reading */
42		bool end_valid; /* whether end is set, otherwise read until EOF */
43
44		/* if not NULL, read file data for this file */
45		zip_t *source_archive;
46		zip_uint64_t source_index;
47
48		zip_uint64_t offset; /* offset in src for next read */
49
50		zip_stat_t stat;
51		zip_uint64_t stat_invalid;
52		zip_file_attributes_t attributes;
53		zip_dostime_t dostime;
54		bool dostime_valid;
55		zip_error_t error;
56		zip_int64_t supports;
57		bool needs_seek;
58		};
59
60		typedef struct window window_t;
61
62		static window_t *window_new(void);
63		static void window_free(window_t *ctx);
64
65		static zip_int64_t window_read(zip_source_t , void , void *, zip_uint64_t, zip_source_cmd_t);
66
67
68	0	ZIP_EXTERN zip_source_t zip_source_window_create(zip_source_t src, zip_uint64_t start, zip_int64_t len, zip_error_t *error) {
69	0	return _zip_source_window_new(src, start, len, NULL, 0, NULL, NULL, NULL, 0, false, error);
70	0	}
71
72
73	0	zip_source_t _zip_source_window_new(zip_source_t src, zip_uint64_t start, zip_int64_t length, zip_stat_t st, zip_uint64_t st_invalid, zip_file_attributes_t attributes, zip_dostime_t dostime, zip_t source_archive, zip_uint64_t source_index, bool take_ownership, zip_error_t *error) {
74	0	zip_source_t *window_source;
75	0	struct window *ctx;
76	0	zip_stat_t lower_st;
77
78	0	if (src == NULL \|\| length < -1 \|\| (source_archive == NULL && source_index != 0)) {
79	0	zip_error_set(error, ZIP_ER_INVAL, 0);
80	0	return NULL;
81	0	}
82
83	0	if (length > 0) {
84	0	if (start + (zip_uint64_t)length < start) {
85	0	zip_error_set(error, ZIP_ER_INVAL, 0);
86	0	return NULL;
87	0	}
88	0	}
89
90	0	zip_stat_init(&lower_st);
91	0	(void)zip_source_stat(src, &lower_st);
92
93	0	if (lower_st.valid & ZIP_STAT_SIZE) {
94	0	if (start > lower_st.size \|\| (length > 0 && start + (zip_uint64_t)length > lower_st.size)) {
95	0	zip_error_set(error, ZIP_ER_INVAL, 0);
96	0	return NULL;
97	0	}
98	0	}
99
100	0	if ((ctx = window_new()) == NULL) {
101	0	zip_error_set(error, ZIP_ER_MEMORY, 0);
102	0	return NULL;
103	0	}
104
105	0	ctx->start = start;
106	0	if (length == -1) {
107	0	ctx->end_valid = false;
108	0	}
109	0	else {
110	0	ctx->end = start + (zip_uint64_t)length;
111	0	ctx->end_valid = true;
112	0	}
113	0	ctx->stat_invalid = st_invalid;
114	0	if (attributes != NULL) {
115	0	(void)memcpy_s(&ctx->attributes, sizeof(ctx->attributes), attributes, sizeof(ctx->attributes));
116	0	}
117	0	if (dostime != NULL) {
118	0	ctx->dostime = *dostime;
119	0	ctx->dostime_valid = true;
120	0	}
121	0	ctx->source_archive = source_archive;
122	0	ctx->source_index = source_index;
123	0	ctx->supports = (zip_source_supports(src) & (ZIP_SOURCE_SUPPORTS_SEEKABLE \| ZIP_SOURCE_SUPPORTS_REOPEN)) \| (zip_source_make_command_bitmap(ZIP_SOURCE_GET_FILE_ATTRIBUTES, ZIP_SOURCE_GET_DOS_TIME, ZIP_SOURCE_SUPPORTS, ZIP_SOURCE_TELL, ZIP_SOURCE_FREE, -1));
124	0	if (ctx->end_valid) {
125	0	ctx->supports \|= ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_AT_EOF);
126	0	}
127	0	ctx->needs_seek = (ctx->supports & ZIP_SOURCE_MAKE_COMMAND_BITMASK(ZIP_SOURCE_SEEK)) ? true : false;
128
129	0	if (st) {
130	0	if (_zip_stat_merge(&ctx->stat, st, error) < 0) {
131	0	window_free(ctx);
132	0	return NULL;
133	0	}
134	0	}
135
136	0	window_source = zip_source_layered_create(src, window_read, ctx, error);
137	0	if (window_source == NULL) {
138	0	window_free(ctx);
139	0	return NULL;
140	0	}
141	0	if (!take_ownership) {
142	0	zip_source_keep(src);
143	0	}
144	0	return window_source;
145	0	}
146
147
148	0	int _zip_source_set_source_archive(zip_source_t src, zip_t za) {
149	0	src->source_archive = za;
150	0	return _zip_register_source(za, src);
151	0	}
152
153
154		/* called by zip_discard to avoid operating on file from closed archive */
155	0	void _zip_source_invalidate(zip_source_t *src) {
156	0	if (ZIP_SOURCE_IS_OPEN_READING(src)) {
157	0	(void)zip_source_close(src);
158	0	}
159
160	0	src->source_closed = 1;
161
162	0	if (zip_error_code_zip(&src->error) == ZIP_ER_OK) {
163	0	zip_error_set(&src->error, ZIP_ER_ZIPCLOSED, 0);
164	0	}
165	0	}
166
167
168	0	static zip_int64_t window_read(zip_source_t src, void _ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
169	0	struct window *ctx;
170	0	zip_int64_t ret;
171	0	zip_uint64_t n, i;
172
173	0	ctx = (struct window *)_ctx;
174
175	0	switch (cmd) {
176	0	case ZIP_SOURCE_AT_EOF:
177	0	if (ctx->end_valid) {
178	0	return ctx->offset == ctx->end;
179	0	}
180	0	else {
181	0	return zip_source_pass_to_lower_layer(src, data, len, cmd);
182	0	}
183
184	0	case ZIP_SOURCE_CLOSE:
185	0	return 0;
186
187	0	case ZIP_SOURCE_ERROR:
188	0	return zip_error_to_data(&ctx->error, data, len);
189
190	0	case ZIP_SOURCE_FREE:
191	0	window_free(ctx);
192	0	return 0;
193
194	0	case ZIP_SOURCE_OPEN:
195	0	if (ctx->source_archive) {
196	0	zip_uint64_t offset;
197
198	0	if ((offset = _zip_file_get_offset(ctx->source_archive, ctx->source_index, &ctx->error)) == 0) {
199	0	return -1;
200	0	}
201	0	if (ctx->end_valid) {
202	0	if (ctx->end + offset < ctx->end) {
203		/* zip archive data claims end of data past zip64 limits */
204	0	zip_error_set(&ctx->error, ZIP_ER_INCONS, MAKE_DETAIL_WITH_INDEX(ZIP_ER_DETAIL_CDIR_ENTRY_INVALID, ctx->source_index));
205	0	return -1;
206	0	}
207	0	ctx->end += offset;
208	0	}
209	0	ctx->start += offset;
210	0	ctx->source_archive = NULL;
211	0	}
212
213	0	if (!ctx->needs_seek) {
214	0	DEFINE_BYTE_ARRAY(b, BUFSIZE);
215
216	0	if (!byte_array_init(b, BUFSIZE)) {
217	0	zip_error_set(&ctx->error, ZIP_ER_MEMORY, 0);
218	0	return -1;
219	0	}
220
221	0	for (n = 0; n < ctx->start; n += (zip_uint64_t)ret) {
222	0	i = (ctx->start - n > BUFSIZE ? BUFSIZE : ctx->start - n);
223	0	if ((ret = zip_source_read(src, b, i)) < 0) {
224	0	zip_error_set_from_source(&ctx->error, src);
225	0	byte_array_fini(b);
226	0	return -1;
227	0	}
228	0	if (ret == 0) {
229	0	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
230	0	byte_array_fini(b);
231	0	return -1;
232	0	}
233	0	}
234
235	0	byte_array_fini(b);
236	0	}
237
238	0	ctx->offset = ctx->start;
239	0	return 0;
240
241	0	case ZIP_SOURCE_READ:
242	0	if (ctx->end_valid && len > ctx->end - ctx->offset) {
243	0	len = ctx->end - ctx->offset;
244	0	}
245
246	0	if (len == 0) {
247	0	return 0;
248	0	}
249
250	0	if (ctx->needs_seek) {
251	0	if (zip_source_seek(src, (zip_int64_t)ctx->offset, SEEK_SET) < 0) {
252	0	zip_error_set_from_source(&ctx->error, src);
253	0	if (zip_error_code_zip(&ctx->error) == ZIP_ER_INVAL) {
254		/* We validated ctx->offset in ZIP_SEEK. */
255	0	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
256	0	}
257	0	return -1;
258	0	}
259	0	}
260
261	0	if ((ret = zip_source_read(src, data, len)) < 0) {
262	0	zip_error_set_from_source(&ctx->error, src);
263	0	return -1;
264	0	}
265
266	0	if (ret == 0) {
267	0	if (ctx->end_valid && ctx->offset < ctx->end) {
268	0	zip_error_set(&ctx->error, ZIP_ER_EOF, 0);
269	0	return -1;
270	0	}
271	0	}
272
273	0	ctx->offset += (zip_uint64_t)ret;
274	0	return ret;
275
276	0	case ZIP_SOURCE_SEEK: {
277	0	zip_uint64_t length;
278	0	zip_int64_t new_offset;
279	0	zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);
280
281		/*
282		If we don't know the length and seek from the end, we seek in the lower source to get the new offset.
283		*/
284	0	if (!ctx->end_valid && args->whence == SEEK_END) {
285	0	zip_int64_t lower_offset;
286
287	0	if (zip_source_seek(src, args->offset, args->whence) < 0) {
288	0	zip_error_set_from_source(&ctx->error, src);
289	0	return -1;
290	0	}
291	0	if ((lower_offset = zip_source_tell(src)) < 0) {
292	0	zip_error_set_from_source(&ctx->error, src);
293	0	return -1;
294	0	}
295	0	if ((zip_uint64_t)lower_offset < ctx->start) {
296	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
297	0	return -1;
298	0	}
299	0	ctx->offset = (zip_uint64_t)lower_offset;
300	0	return 0;
301	0	}
302
303		/*
304		If we don't know the length, we disable the end check in zip_source_seek_compute_offset by passing in the largest possible value and seek in the lower source to validate the new offset.
305		*/
306	0	length = ctx->end_valid ? (ctx->end - ctx->start) : ZIP_INT64_MAX;
307	0	new_offset = zip_source_seek_compute_offset(ctx->offset - ctx->start, length, data, len, &ctx->error);
308
309	0	if (new_offset < 0) {
310	0	return -1;
311	0	}
312
313	0	if (new_offset + ctx->start < ctx->start) {
314	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
315	0	return -1;
316	0	}
317	0	new_offset += ctx->start;
318
319	0	if (!ctx->end_valid) {
320	0	if (zip_source_seek(src, new_offset, SEEK_SET) < 0) {
321	0	zip_error_set_from_source(&ctx->error, src);
322	0	return -1;
323	0	}
324	0	}
325	0	ctx->offset = (zip_uint64_t)new_offset;
326	0	return 0;
327	0	}
328
329	0	case ZIP_SOURCE_STAT: {
330	0	zip_stat_t *st;
331
332	0	st = (zip_stat_t *)data;
333
334	0	if (_zip_stat_merge(st, &ctx->stat, &ctx->error) < 0) {
335	0	return -1;
336	0	}
337
338	0	if (!(ctx->stat.valid & ZIP_STAT_SIZE)) {
339	0	if (ctx->end_valid) {
340	0	st->valid \|= ZIP_STAT_SIZE;
341	0	st->size = ctx->end - ctx->start;
342	0	}
343	0	else if (st->valid & ZIP_STAT_SIZE) {
344	0	if (st->size < ctx->start) {
345	0	st->valid &= ~ZIP_STAT_SIZE;
346	0	}
347	0	else {
348	0	st->size -= ctx->start;
349	0	}
350	0	}
351	0	}
352
353	0	st->valid &= ~ctx->stat_invalid;
354
355	0	return 0;
356	0	}
357
358	0	case ZIP_SOURCE_GET_FILE_ATTRIBUTES:
359	0	if (len < sizeof(ctx->attributes)) {
360	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
361	0	return -1;
362	0	}
363
364	0	(void)memcpy_s(data, sizeof(ctx->attributes), &ctx->attributes, sizeof(ctx->attributes));
365	0	return sizeof(ctx->attributes);
366
367	0	case ZIP_SOURCE_GET_DOS_TIME:
368	0	if (len < sizeof(ctx->dostime)) {
369	0	zip_error_set(&ctx->error, ZIP_ER_INVAL, 0);
370	0	return -1;
371	0	}
372	0	if (ctx->dostime_valid) {
373	0	(void)memcpy_s(data, sizeof(ctx->dostime), &ctx->dostime, sizeof(ctx->dostime));
374	0	return sizeof(ctx->dostime);
375	0	}
376	0	else {
377	0	return 0;
378	0	}
379
380	0	case ZIP_SOURCE_SUPPORTS:
381	0	return ctx->supports;
382
383	0	case ZIP_SOURCE_TELL:
384	0	return (zip_int64_t)(ctx->offset - ctx->start);
385
386	0	default:
387	0	return zip_source_pass_to_lower_layer(src, data, len, cmd);
388	0	}
389	0	}
390
391
392	0	void _zip_deregister_source(zip_t za, zip_source_t src) {
393	0	zip_uint64_t i;
394
395	0	for (i = 0; i < za->nopen_source; i++) {
396	0	if (za->open_source[i] == src) {
397	0	za->open_source[i] = za->open_source[za->nopen_source - 1];
398	0	za->nopen_source--;
399	0	break;
400	0	}
401	0	}
402	0	}
403
404
405	0	int _zip_register_source(zip_t za, zip_source_t src) {
406	0	if (za->nopen_source + 1 >= za->nopen_source_alloc) {
407	0	if (!ZIP_REALLOC(za->open_source, za->nopen_source_alloc, 10, &za->error)) {
408	0	return -1;
409	0	}
410	0	}
411
412	0	za->open_source[za->nopen_source++] = src;
413
414	0	return 0;
415	0	}
416
417	0	static window_t *window_new(void) {
418	0	window_t *ctx;
419
420	0	if ((ctx = (window_t *)malloc(sizeof(window_t))) == NULL) {
421	0	return NULL;
422	0	}
423
424	0	ctx->start = 0;
425	0	ctx->end = 0;
426	0	ctx->end_valid = false;
427	0	ctx->source_archive = NULL;
428	0	ctx->source_index = 0;
429	0	ctx->offset = 0;
430	0	zip_stat_init(&ctx->stat);
431	0	ctx->stat_invalid = 0;
432	0	zip_file_attributes_init(&ctx->attributes);
433	0	ctx->dostime_valid = false;
434	0	zip_error_init(&ctx->error);
435	0	ctx->supports = 0;
436	0	ctx->needs_seek = false;
437
438	0	return ctx;
439	0	}
440
441	0	static void window_free(window_t *ctx) {
442	0	if (ctx == NULL) {
443	0	return;
444	0	}
445
446	0	zip_error_fini(&ctx->error);
447	0	free(ctx);
448	0	}