1 /* 2 * Copyright (c) 2016, EMC / Isilon Storage Division 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS 15 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 16 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR 18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/fcntl.h> 31 32 #include <errno.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 36 #include "local.h" 37 38 struct fopencookie_thunk { 39 void *foc_cookie; 40 cookie_io_functions_t foc_io; 41 }; 42 43 static int _fopencookie_read(void *, char *, int); 44 static int _fopencookie_write(void *, const char *, int); 45 static fpos_t _fopencookie_seek(void *, fpos_t, int); 46 static int _fopencookie_close(void *); 47 48 FILE * 49 fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs) 50 { 51 int (*readfn)(void *, char *, int); 52 int (*writefn)(void *, const char *, int); 53 struct fopencookie_thunk *thunk; 54 FILE *fp; 55 int flags, oflags; 56 57 if ((flags = __sflags(mode, &oflags)) == 0) 58 return (NULL); 59 60 thunk = malloc(sizeof(*thunk)); 61 if (thunk == NULL) 62 return (NULL); 63 64 thunk->foc_cookie = cookie; 65 thunk->foc_io = io_funcs; 66 67 readfn = _fopencookie_read; 68 writefn = _fopencookie_write; 69 if (flags == __SWR) 70 readfn = NULL; 71 else if (flags == __SRD) 72 writefn = NULL; 73 74 fp = funopen(thunk, readfn, writefn, _fopencookie_seek, 75 _fopencookie_close); 76 if (fp == NULL) { 77 free(thunk); 78 return (NULL); 79 } 80 81 if ((oflags & O_APPEND) != 0) 82 fp->_flags |= __SAPP; 83 84 return (fp); 85 } 86 87 static int 88 _fopencookie_read(void *cookie, char *buf, int size) 89 { 90 struct fopencookie_thunk *thunk; 91 92 thunk = cookie; 93 94 /* Reads from a stream with NULL read return EOF. */ 95 if (thunk->foc_io.read == NULL) 96 return (0); 97 98 return ((int)thunk->foc_io.read(thunk->foc_cookie, buf, (size_t)size)); 99 } 100 101 static int 102 _fopencookie_write(void *cookie, const char *buf, int size) 103 { 104 struct fopencookie_thunk *thunk; 105 106 thunk = cookie; 107 108 /* Writes to a stream with NULL write discard data. */ 109 if (thunk->foc_io.write == NULL) 110 return (size); 111 112 return ((int)thunk->foc_io.write(thunk->foc_cookie, buf, 113 (size_t)size)); 114 } 115 116 static fpos_t 117 _fopencookie_seek(void *cookie, fpos_t offset, int whence) 118 { 119 struct fopencookie_thunk *thunk; 120 off64_t off64; 121 int res; 122 123 switch (whence) { 124 case SEEK_SET: 125 case SEEK_CUR: 126 case SEEK_END: 127 break; 128 default: 129 /* fopencookie(3) only allows these three seek modes. */ 130 errno = EINVAL; 131 return (-1); 132 } 133 134 thunk = cookie; 135 136 /* 137 * If seek is NULL, it is not possible to perform seek operations on 138 * the stream. 139 */ 140 if (thunk->foc_io.seek == NULL) { 141 errno = ENOTSUP; 142 return (-1); 143 } 144 145 off64 = (off64_t)offset; 146 res = thunk->foc_io.seek(thunk->foc_cookie, &off64, whence); 147 if (res < 0) 148 return (res); 149 150 return ((fpos_t)off64); 151 } 152 153 static int 154 _fopencookie_close(void *cookie) 155 { 156 struct fopencookie_thunk *thunk; 157 int ret, serrno; 158 159 ret = 0; 160 thunk = cookie; 161 if (thunk->foc_io.close != NULL) 162 ret = thunk->foc_io.close(thunk->foc_cookie); 163 164 serrno = errno; 165 free(thunk); 166 errno = serrno; 167 return (ret); 168 } 169