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 #include <sys/fcntl.h> 29 30 #include <errno.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 34 #include "local.h" 35 36 struct fopencookie_thunk { 37 void *foc_cookie; 38 cookie_io_functions_t foc_io; 39 }; 40 41 static int _fopencookie_read(void *, char *, int); 42 static int _fopencookie_write(void *, const char *, int); 43 static fpos_t _fopencookie_seek(void *, fpos_t, int); 44 static int _fopencookie_close(void *); 45 46 FILE * 47 fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs) 48 { 49 int (*readfn)(void *, char *, int); 50 int (*writefn)(void *, const char *, int); 51 struct fopencookie_thunk *thunk; 52 FILE *fp; 53 int flags, oflags; 54 55 if ((flags = __sflags(mode, &oflags)) == 0) 56 return (NULL); 57 58 thunk = malloc(sizeof(*thunk)); 59 if (thunk == NULL) 60 return (NULL); 61 62 thunk->foc_cookie = cookie; 63 thunk->foc_io = io_funcs; 64 65 readfn = _fopencookie_read; 66 writefn = _fopencookie_write; 67 if (flags == __SWR) 68 readfn = NULL; 69 else if (flags == __SRD) 70 writefn = NULL; 71 72 fp = funopen(thunk, readfn, writefn, _fopencookie_seek, 73 _fopencookie_close); 74 if (fp == NULL) { 75 free(thunk); 76 return (NULL); 77 } 78 79 if ((oflags & O_APPEND) != 0) 80 fp->_flags |= __SAPP; 81 82 return (fp); 83 } 84 85 static int 86 _fopencookie_read(void *cookie, char *buf, int size) 87 { 88 struct fopencookie_thunk *thunk; 89 90 thunk = cookie; 91 92 /* Reads from a stream with NULL read return EOF. */ 93 if (thunk->foc_io.read == NULL) 94 return (0); 95 96 return ((int)thunk->foc_io.read(thunk->foc_cookie, buf, (size_t)size)); 97 } 98 99 static int 100 _fopencookie_write(void *cookie, const char *buf, int size) 101 { 102 struct fopencookie_thunk *thunk; 103 104 thunk = cookie; 105 106 /* Writes to a stream with NULL write discard data. */ 107 if (thunk->foc_io.write == NULL) 108 return (size); 109 110 return ((int)thunk->foc_io.write(thunk->foc_cookie, buf, 111 (size_t)size)); 112 } 113 114 static fpos_t 115 _fopencookie_seek(void *cookie, fpos_t offset, int whence) 116 { 117 struct fopencookie_thunk *thunk; 118 off64_t off64; 119 int res; 120 121 switch (whence) { 122 case SEEK_SET: 123 case SEEK_CUR: 124 case SEEK_END: 125 break; 126 default: 127 /* fopencookie(3) only allows these three seek modes. */ 128 errno = EINVAL; 129 return (-1); 130 } 131 132 thunk = cookie; 133 134 /* 135 * If seek is NULL, it is not possible to perform seek operations on 136 * the stream. 137 */ 138 if (thunk->foc_io.seek == NULL) { 139 errno = ENOTSUP; 140 return (-1); 141 } 142 143 off64 = (off64_t)offset; 144 res = thunk->foc_io.seek(thunk->foc_cookie, &off64, whence); 145 if (res < 0) 146 return (res); 147 148 return ((fpos_t)off64); 149 } 150 151 static int 152 _fopencookie_close(void *cookie) 153 { 154 struct fopencookie_thunk *thunk; 155 int ret, serrno; 156 157 ret = 0; 158 thunk = cookie; 159 if (thunk->foc_io.close != NULL) 160 ret = thunk->foc_io.close(thunk->foc_cookie); 161 162 serrno = errno; 163 free(thunk); 164 errno = serrno; 165 return (ret); 166 } 167