Annotation of src/usr.bin/compress/gzopen.c, Revision 1.12
1.12 ! millert 1: /* $OpenBSD: gzopen.c,v 1.11 2003/07/10 00:06:50 david Exp $ */
1.1 mickey 2:
3: /*
4: * Copyright (c) 1997 Michael Shalayeff
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: *
1.5 mickey 16: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1.1 mickey 18: * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26: * SUCH DAMAGE.
27: *
28: */
29: /* this is partially derived from the zlib's gzio.c file, so the notice: */
30: /*
31: zlib.h -- interface of the 'zlib' general purpose compression library
32: version 1.0.4, Jul 24th, 1996.
33:
34: Copyright (C) 1995-1996 Jean-loup Gailly and Mark Adler
35:
36: This software is provided 'as-is', without any express or implied
37: warranty. In no event will the authors be held liable for any damages
38: arising from the use of this software.
39:
40: Permission is granted to anyone to use this software for any purpose,
41: including commercial applications, and to alter it and redistribute it
42: freely, subject to the following restrictions:
43:
44: 1. The origin of this software must not be misrepresented; you must not
45: claim that you wrote the original software. If you use this software
46: in a product, an acknowledgment in the product documentation would be
47: appreciated but is not required.
48: 2. Altered source versions must be plainly marked as such, and must not be
49: misrepresented as being the original software.
50: 3. This notice may not be removed or altered from any source distribution.
51:
52: Jean-loup Gailly Mark Adler
53: gzip@prep.ai.mit.edu madler@alumni.caltech.edu
54:
55:
56: The data format used by the zlib library is described by RFCs (Request for
57: Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
58: (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
59: */
60:
1.5 mickey 61: const char gz_rcsid[] =
1.12 ! millert 62: "$OpenBSD: gzopen.c,v 1.11 2003/07/10 00:06:50 david Exp $";
1.5 mickey 63:
1.1 mickey 64: #include <sys/types.h>
65: #include <sys/stat.h>
66: #include <stdio.h>
67: #include <stdlib.h>
1.11 david 68: #include <string.h>
1.1 mickey 69: #include <errno.h>
70: #include <unistd.h>
71: #include <zlib.h>
72: #include "compress.h"
73:
74: /* gzip flag byte */
75: #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
76: #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */
77: #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
78: #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
79: #define COMMENT 0x10 /* bit 4 set: file comment present */
80: #define RESERVED 0xE0 /* bits 5..7: reserved */
81:
82: #define DEF_MEM_LEVEL 8
83: #define OS_CODE 0x03 /* unix */
84:
85: typedef
86: struct gz_stream {
87: int z_fd; /* .gz file */
88: z_stream z_stream; /* libz stream */
89: int z_eof; /* set if end of input file */
90: u_char z_buf[Z_BUFSIZE]; /* i/o buffer */
91: u_int32_t z_crc; /* crc32 of uncompressed data */
92: char z_mode; /* 'w' or 'r' */
93:
94: } gz_stream;
95:
1.5 mickey 96: static const u_char gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
1.1 mickey 97:
1.3 millert 98: static int put_int32(gz_stream *, u_int32_t);
99: static u_int32_t get_int32(gz_stream *);
1.12 ! millert 100: static int get_header(gz_stream *, int);
1.3 millert 101: static int get_byte(gz_stream *);
1.1 mickey 102:
103: void *
1.12 ! millert 104: gz_open(int fd, const char *mode, int bits, int gotmagic)
1.1 mickey 105: {
106: gz_stream *s;
107:
108: if (fd < 0 || !mode)
109: return NULL;
110:
111: if ((mode[0] != 'r' && mode[0] != 'w') || mode[1] != '\0' ||
112: bits < 0 || bits > Z_BEST_COMPRESSION) {
113: errno = EINVAL;
114: return NULL;
115: }
1.4 aaron 116: if ((s = (gz_stream *)calloc(1, sizeof(gz_stream))) == NULL)
1.1 mickey 117: return NULL;
118:
119: s->z_stream.zalloc = (alloc_func)0;
120: s->z_stream.zfree = (free_func)0;
121: s->z_stream.opaque = (voidpf)0;
122: s->z_stream.next_in = Z_NULL;
123: s->z_stream.next_out = Z_NULL;
124: s->z_stream.avail_in = s->z_stream.avail_out = 0;
125: s->z_fd = 0;
126: s->z_eof = 0;
127: s->z_crc = crc32(0L, Z_NULL, 0);
128: s->z_mode = mode[0];
129:
130: if (s->z_mode == 'w') {
131: /* windowBits is passed < 0 to suppress zlib header */
132: if (deflateInit2(&(s->z_stream), bits, Z_DEFLATED,
133: -MAX_WBITS, DEF_MEM_LEVEL, 0) != Z_OK) {
134: free (s);
135: return NULL;
136: }
137: s->z_stream.next_out = s->z_buf;
138: } else {
139: if (inflateInit2(&(s->z_stream), -MAX_WBITS) != Z_OK) {
140: free (s);
141: return NULL;
142: }
143: s->z_stream.next_in = s->z_buf;
144: }
145: s->z_stream.avail_out = Z_BUFSIZE;
146:
147: errno = 0;
148: s->z_fd = fd;
149:
150: if (s->z_mode == 'w') {
151: u_char buf[10];
152: /* Write a very simple .gz header: */
153: buf[0] = gz_magic[0];
154: buf[1] = gz_magic[1];
155: buf[2] = Z_DEFLATED;
156: buf[3] = 0 /*flags*/;
157: buf[4] = buf[5] = buf[6] = buf[7] = 0 /*time*/;
158: buf[8] = 0 /*xflags*/;
159: buf[9] = OS_CODE;
160: if (write(fd, buf, sizeof(buf)) != sizeof(buf)) {
161: gz_close(s);
162: s = NULL;
163: }
164: } else {
1.12 ! millert 165: if (get_header(s, gotmagic) != 0) { /* skip the .gz header */
1.1 mickey 166: gz_close (s);
167: s = NULL;
168: }
169: }
170:
171: return s;
172: }
173:
174: int
1.7 deraadt 175: gz_close(void *cookie)
1.1 mickey 176: {
1.2 mpech 177: gz_stream *s = (gz_stream*)cookie;
1.1 mickey 178: int err = 0;
179:
180: if (s == NULL)
181: return -1;
182:
183: if (s->z_mode == 'w' && (err = gz_flush (s, Z_FINISH)) == Z_OK) {
184: if ((err = put_int32 (s, s->z_crc)) == Z_OK)
185: err = put_int32 (s, s->z_stream.total_in);
186: }
187:
188: if (!err && s->z_stream.state != NULL) {
189: if (s->z_mode == 'w')
190: err = deflateEnd(&s->z_stream);
191: else if (s->z_mode == 'r')
192: err = inflateEnd(&s->z_stream);
193: }
1.10 mickey 194:
195: if (!err)
196: err = close(s->z_fd);
197: else
198: (void)close(s->z_fd);
1.1 mickey 199:
200: free(s);
201:
202: return err;
203: }
204:
205: int
1.7 deraadt 206: gz_flush(void *cookie, int flush)
1.1 mickey 207: {
1.2 mpech 208: gz_stream *s = (gz_stream*)cookie;
1.1 mickey 209: size_t len;
210: int done = 0;
211: int err;
212:
213: if (s == NULL || s->z_mode != 'w') {
214: errno = EBADF;
215: return Z_ERRNO;
216: }
217:
218: s->z_stream.avail_in = 0; /* should be zero already anyway */
219:
220: for (;;) {
221: len = Z_BUFSIZE - s->z_stream.avail_out;
222:
223: if (len != 0) {
224: if (write(s->z_fd, s->z_buf, len) != len)
225: return Z_ERRNO;
226: s->z_stream.next_out = s->z_buf;
227: s->z_stream.avail_out = Z_BUFSIZE;
228: }
229: if (done)
230: break;
231: if ((err = deflate(&(s->z_stream), flush)) != Z_OK &&
232: err != Z_STREAM_END)
233: return err;
234:
235: /* deflate has finished flushing only when it hasn't
236: * used up all the available space in the output buffer
237: */
238: done = (s->z_stream.avail_out != 0 || err == Z_STREAM_END);
239: }
240: return 0;
241: }
242:
243: static int
1.7 deraadt 244: put_int32(gz_stream *s, u_int32_t x)
1.1 mickey 245: {
1.8 millert 246: u_int32_t y = htole32(x);
247:
248: if (write(s->z_fd, &y, sizeof(y)) != sizeof(y))
1.1 mickey 249: return Z_ERRNO;
250: return 0;
251: }
252:
253: static int
1.7 deraadt 254: get_byte(gz_stream *s)
1.1 mickey 255: {
256: if (s->z_eof)
257: return EOF;
1.5 mickey 258:
1.1 mickey 259: if (s->z_stream.avail_in == 0) {
260: errno = 0;
261: s->z_stream.avail_in = read(s->z_fd, s->z_buf, Z_BUFSIZE);
262: if (s->z_stream.avail_in <= 0) {
263: s->z_eof = 1;
264: return EOF;
265: }
266: s->z_stream.next_in = s->z_buf;
267: }
268: s->z_stream.avail_in--;
269: return *s->z_stream.next_in++;
270: }
271:
1.5 mickey 272: static u_int32_t
1.7 deraadt 273: get_int32(gz_stream *s)
1.1 mickey 274: {
1.2 mpech 275: u_int32_t x;
1.1 mickey 276:
277: x = ((u_int32_t)(get_byte(s) & 0xff));
278: x |= ((u_int32_t)(get_byte(s) & 0xff))<<8;
279: x |= ((u_int32_t)(get_byte(s) & 0xff))<<16;
280: x |= ((u_int32_t)(get_byte(s) & 0xff))<<24;
281: return x;
282: }
283:
284: static int
1.12 ! millert 285: get_header(gz_stream *s, int gotmagic)
1.1 mickey 286: {
287: int method; /* method byte */
288: int flags; /* flags byte */
289: uInt len;
290: int c;
291:
292: /* Check the gzip magic header */
1.12 ! millert 293: if (!gotmagic) {
! 294: for (len = 0; len < 2; len++) {
! 295: c = get_byte(s);
! 296: if (c != gz_magic[len]) {
! 297: errno = EFTYPE;
! 298: return -1;
! 299: }
1.1 mickey 300: }
301: }
302:
303: method = get_byte(s);
304: flags = get_byte(s);
305: if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
306: errno = EFTYPE;
307: return -1;
308: }
309:
310: /* Discard time, xflags and OS code: */
311: for (len = 0; len < 6; len++)
312: (void)get_byte(s);
313:
314: if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
315: len = (uInt)get_byte(s);
316: len += ((uInt)get_byte(s))<<8;
317: /* len is garbage if EOF but the loop below will quit anyway */
318: while (len-- != 0 && get_byte(s) != EOF)
319: ;
320: }
321:
322: if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
323: while ((c = get_byte(s)) != 0 && c != EOF) ;
324: }
325:
326: if ((flags & COMMENT) != 0) { /* skip the .gz file comment */
327: while ((c = get_byte(s)) != 0 && c != EOF) ;
328: }
329:
330: if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
331: for (len = 0; len < 2; len++) (void)get_byte(s);
332: }
333:
334: if (s->z_eof) {
335: errno = EFTYPE;
336: return -1;
337: }
338:
339: return 0;
340: }
341:
342: int
1.7 deraadt 343: gz_read(void *cookie, char *buf, int len)
1.1 mickey 344: {
1.2 mpech 345: gz_stream *s = (gz_stream*)cookie;
1.1 mickey 346: u_char *start = buf; /* starting point for crc computation */
347:
348: s->z_stream.next_out = buf;
349: s->z_stream.avail_out = len;
350:
351: while (s->z_stream.avail_out != 0 && !s->z_eof) {
352:
353: if (s->z_stream.avail_in == 0) {
354:
355: errno = 0;
356: if ((s->z_stream.avail_in =
1.7 deraadt 357: read(s->z_fd, s->z_buf, Z_BUFSIZE)) == 0)
1.1 mickey 358: s->z_eof = 1;
359: s->z_stream.next_in = s->z_buf;
360: }
361:
362: if (inflate(&(s->z_stream), Z_NO_FLUSH) == Z_STREAM_END) {
363: /* Check CRC and original size */
364: s->z_crc = crc32(s->z_crc, start,
1.7 deraadt 365: (uInt)(s->z_stream.next_out - start));
1.1 mickey 366: start = s->z_stream.next_out;
367:
1.9 millert 368: if (get_int32(s) != s->z_crc) {
369: errno = EINVAL;
370: return -1;
371: }
372: if (get_int32(s) != s->z_stream.total_out) {
1.7 deraadt 373: errno = EIO;
1.1 mickey 374: return -1;
375: }
376: s->z_eof = 1;
377: break;
378: }
379: }
380: s->z_crc = crc32(s->z_crc, start,
1.7 deraadt 381: (uInt)(s->z_stream.next_out - start));
1.1 mickey 382:
383: return (int)(len - s->z_stream.avail_out);
384: }
385:
386: int
1.7 deraadt 387: gz_write(void *cookie, const char *buf, int len)
1.1 mickey 388: {
1.2 mpech 389: gz_stream *s = (gz_stream*)cookie;
1.1 mickey 390:
391: s->z_stream.next_in = (char *)buf;
392: s->z_stream.avail_in = len;
393:
394: while (s->z_stream.avail_in != 0) {
395: if (s->z_stream.avail_out == 0) {
396: if (write(s->z_fd, s->z_buf, Z_BUFSIZE) != Z_BUFSIZE)
397: break;
398: s->z_stream.next_out = s->z_buf;
399: s->z_stream.avail_out = Z_BUFSIZE;
400: }
401: if (deflate(&(s->z_stream), Z_NO_FLUSH) != Z_OK)
402: break;
403: }
404: s->z_crc = crc32(s->z_crc, buf, len);
405:
406: return (int)(len - s->z_stream.avail_in);
407: }
408:
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