1 /* $OpenBSD: nullopen.c,v 1.6 2016/09/03 11:41:10 tedu Exp $ */
2
3 /*
4 * Copyright (c) 2003 Can Erkin Acar
5 * Copyright (c) 1997 Michael Shalayeff
6 * All rights reserved.
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 the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 */
30
31 #include <sys/types.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <errno.h>
35 #include <unistd.h>
36 #include "compress.h"
37
38 typedef struct {
39 off_t total_in;
40 off_t total_out;
41 int fd;
42 int gotmagic;
43 char mode;
44 } null_stream;
45
46 char null_magic[2];
47
48
49 void *
null_ropen(int fd,char * name,int gotmagic)50 null_ropen(int fd, char *name, int gotmagic)
51 {
52 null_stream *s;
53
54 if (fd < 0)
55 return NULL;
56
57 if ((s = calloc(1, sizeof(null_stream))) == NULL)
58 return NULL;
59
60 s->fd = fd;
61 s->gotmagic = gotmagic;
62 s->total_in = s->total_out = 0;
63 s->mode = 'r';
64
65 return s;
66 }
67
68 void *
null_wopen(int fd,char * name,int bits,u_int32_t mtime)69 null_wopen(int fd, char *name, int bits, u_int32_t mtime)
70 {
71 null_stream *s;
72
73 if (fd < 0)
74 return NULL;
75
76 if ((s = calloc(1, sizeof(null_stream))) == NULL)
77 return NULL;
78
79 s->fd = fd;
80 s->gotmagic = 0;
81 s->total_in = s->total_out = 0;
82 s->mode = 'w';
83
84 return s;
85 }
86
87 int
null_close(void * cookie,struct z_info * info,const char * name,struct stat * sb)88 null_close(void *cookie, struct z_info *info, const char *name, struct stat *sb)
89 {
90 null_stream *s = (null_stream*) cookie;
91 int err = 0;
92
93 if (s == NULL)
94 return -1;
95
96
97 if (info != NULL) {
98 info->mtime = 0;
99 info->crc = (u_int32_t)-1;
100 info->hlen = 0;
101 info->total_in = (off_t) s->total_in;
102 info->total_out = (off_t) s->total_out;
103 }
104
105 setfile(name, s->fd, sb);
106 err = close(s->fd);
107
108 free(s);
109
110 return err;
111 }
112
113 int
null_flush(void * cookie,int flush)114 null_flush(void *cookie, int flush)
115 {
116 null_stream *s = (null_stream*)cookie;
117
118 if (s == NULL || s->mode != 'w') {
119 errno = EBADF;
120 return (-1);
121 }
122
123 return 0;
124 }
125
126 int
null_read(void * cookie,char * buf,int len)127 null_read(void *cookie, char *buf, int len)
128 {
129 null_stream *s = (null_stream*)cookie;
130
131 if (s == NULL) {
132 errno = EBADF;
133 return (-1);
134 }
135 if (s->gotmagic) {
136 if (len < 2) {
137 errno = EBADF;
138 return (-1);
139 }
140
141 buf[0] = null_magic[0];
142 buf[1] = null_magic[1];
143 s->gotmagic = 0;
144
145 return (2);
146 }
147
148 return read(s->fd, buf, len);
149 }
150
151 int
null_write(void * cookie,const char * buf,int len)152 null_write(void *cookie, const char *buf, int len)
153 {
154 null_stream *s = (null_stream*)cookie;
155
156 if (s == NULL) {
157 errno = EBADF;
158 return (-1);
159 }
160
161 return write(s->fd, buf, len);
162 }
163