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/fcntl.h> 28 29 #include <errno.h> 30 #include <stdio.h> 31 #include <stdlib.h> 32 33 #include "local.h" 34 35 struct fopencookie_thunk { 36 void *foc_cookie; 37 cookie_io_functions_t foc_io; 38 }; 39 40 static int _fopencookie_read(void *, char *, int); 41 static int _fopencookie_write(void *, const char *, int); 42 static fpos_t _fopencookie_seek(void *, fpos_t, int); 43 static int _fopencookie_close(void *); 44 45 FILE * 46 fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs) 47 { 48 int (*readfn)(void *, char *, int); 49 int (*writefn)(void *, const char *, int); 50 struct fopencookie_thunk *thunk; 51 FILE *fp; 52 int flags, oflags; 53 54 if ((flags = __sflags(mode, &oflags)) == 0) 55 return (NULL); 56 57 thunk = malloc(sizeof(*thunk)); 58 if (thunk == NULL) 59 return (NULL); 60 61 thunk->foc_cookie = cookie; 62 thunk->foc_io = io_funcs; 63 64 readfn = _fopencookie_read; 65 writefn = _fopencookie_write; 66 if (flags == __SWR) 67 readfn = NULL; 68 else if (flags == __SRD) 69 writefn = NULL; 70 71 fp = funopen(thunk, readfn, writefn, _fopencookie_seek, 72 _fopencookie_close); 73 if (fp == NULL) { 74 free(thunk); 75 return (NULL); 76 } 77 78 if ((oflags & O_APPEND) != 0) 79 fp->_flags |= __SAPP; 80 81 return (fp); 82 } 83 84 static int 85 _fopencookie_read(void *cookie, char *buf, int size) 86 { 87 struct fopencookie_thunk *thunk; 88 89 thunk = cookie; 90 91 /* Reads from a stream with NULL read return EOF. */ 92 if (thunk->foc_io.read == NULL) 93 return (0); 94 95 return ((int)thunk->foc_io.read(thunk->foc_cookie, buf, (size_t)size)); 96 } 97 98 static int 99 _fopencookie_write(void *cookie, const char *buf, int size) 100 { 101 struct fopencookie_thunk *thunk; 102 103 thunk = cookie; 104 105 /* Writes to a stream with NULL write discard data. */ 106 if (thunk->foc_io.write == NULL) 107 return (size); 108 109 return ((int)thunk->foc_io.write(thunk->foc_cookie, buf, 110 (size_t)size)); 111 } 112 113 static fpos_t 114 _fopencookie_seek(void *cookie, fpos_t offset, int whence) 115 { 116 struct fopencookie_thunk *thunk; 117 off64_t off64; 118 int res; 119 120 switch (whence) { 121 case SEEK_SET: 122 case SEEK_CUR: 123 case SEEK_END: 124 break; 125 default: 126 /* fopencookie(3) only allows these three seek modes. */ 127 errno = EINVAL; 128 return (-1); 129 } 130 131 thunk = cookie; 132 133 /* 134 * If seek is NULL, it is not possible to perform seek operations on 135 * the stream. 136 */ 137 if (thunk->foc_io.seek == NULL) { 138 errno = ENOTSUP; 139 return (-1); 140 } 141 142 off64 = (off64_t)offset; 143 res = thunk->foc_io.seek(thunk->foc_cookie, &off64, whence); 144 if (res < 0) 145 return (res); 146 147 return ((fpos_t)off64); 148 } 149 150 static int 151 _fopencookie_close(void *cookie) 152 { 153 struct fopencookie_thunk *thunk; 154 int ret, serrno; 155 156 ret = 0; 157 thunk = cookie; 158 if (thunk->foc_io.close != NULL) 159 ret = thunk->foc_io.close(thunk->foc_cookie); 160 161 serrno = errno; 162 free(thunk); 163 errno = serrno; 164 return (ret); 165 } 166