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 * 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 * 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 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 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 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 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