1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2013 Hudson River Trading LLC 5 * Written by: John H. Baldwin <jhb@FreeBSD.org> 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 AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR 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 #include <sys/cdefs.h> 31 #include "namespace.h" 32 #include <assert.h> 33 #include <errno.h> 34 #include <limits.h> 35 #ifdef DEBUG 36 #include <stdint.h> 37 #endif 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <wchar.h> 42 #include "un-namespace.h" 43 44 /* XXX: There is no FPOS_MAX. This assumes fpos_t is an off_t. */ 45 #define FPOS_MAX OFF_MAX 46 47 struct memstream { 48 char **bufp; 49 size_t *sizep; 50 ssize_t len; 51 fpos_t offset; 52 }; 53 54 static int 55 memstream_grow(struct memstream *ms, fpos_t newoff) 56 { 57 char *buf; 58 ssize_t newsize; 59 60 if (newoff < 0 || newoff >= SSIZE_MAX) 61 newsize = SSIZE_MAX - 1; 62 else 63 newsize = newoff; 64 if (newsize > ms->len) { 65 buf = realloc(*ms->bufp, newsize + 1); 66 if (buf != NULL) { 67 #ifdef DEBUG 68 fprintf(stderr, "MS: %p growing from %zd to %zd\n", 69 ms, ms->len, newsize); 70 #endif 71 memset(buf + ms->len + 1, 0, newsize - ms->len); 72 *ms->bufp = buf; 73 ms->len = newsize; 74 return (1); 75 } 76 return (0); 77 } 78 return (1); 79 } 80 81 static void 82 memstream_update(struct memstream *ms) 83 { 84 85 assert(ms->len >= 0 && ms->offset >= 0); 86 *ms->sizep = ms->len < ms->offset ? ms->len : ms->offset; 87 } 88 89 static int 90 memstream_write(void *cookie, const char *buf, int len) 91 { 92 struct memstream *ms; 93 ssize_t tocopy; 94 95 ms = cookie; 96 if (!memstream_grow(ms, ms->offset + len)) 97 return (-1); 98 tocopy = ms->len - ms->offset; 99 if (len < tocopy) 100 tocopy = len; 101 memcpy(*ms->bufp + ms->offset, buf, tocopy); 102 ms->offset += tocopy; 103 memstream_update(ms); 104 #ifdef DEBUG 105 fprintf(stderr, "MS: write(%p, %d) = %zd\n", ms, len, tocopy); 106 #endif 107 return (tocopy); 108 } 109 110 static fpos_t 111 memstream_seek(void *cookie, fpos_t pos, int whence) 112 { 113 struct memstream *ms; 114 #ifdef DEBUG 115 fpos_t old; 116 #endif 117 118 ms = cookie; 119 #ifdef DEBUG 120 old = ms->offset; 121 #endif 122 switch (whence) { 123 case SEEK_SET: 124 /* _fseeko() checks for negative offsets. */ 125 assert(pos >= 0); 126 ms->offset = pos; 127 break; 128 case SEEK_CUR: 129 /* This is only called by _ftello(). */ 130 assert(pos == 0); 131 break; 132 case SEEK_END: 133 if (pos < 0) { 134 if (pos + ms->len < 0) { 135 #ifdef DEBUG 136 fprintf(stderr, 137 "MS: bad SEEK_END: pos %jd, len %zd\n", 138 (intmax_t)pos, ms->len); 139 #endif 140 errno = EINVAL; 141 return (-1); 142 } 143 } else { 144 if (FPOS_MAX - ms->len < pos) { 145 #ifdef DEBUG 146 fprintf(stderr, 147 "MS: bad SEEK_END: pos %jd, len %zd\n", 148 (intmax_t)pos, ms->len); 149 #endif 150 errno = EOVERFLOW; 151 return (-1); 152 } 153 } 154 ms->offset = ms->len + pos; 155 break; 156 } 157 memstream_update(ms); 158 #ifdef DEBUG 159 fprintf(stderr, "MS: seek(%p, %jd, %d) %jd -> %jd\n", ms, (intmax_t)pos, 160 whence, (intmax_t)old, (intmax_t)ms->offset); 161 #endif 162 return (ms->offset); 163 } 164 165 static int 166 memstream_close(void *cookie) 167 { 168 169 free(cookie); 170 return (0); 171 } 172 173 FILE * 174 open_memstream(char **bufp, size_t *sizep) 175 { 176 struct memstream *ms; 177 int save_errno; 178 FILE *fp; 179 180 if (bufp == NULL || sizep == NULL) { 181 errno = EINVAL; 182 return (NULL); 183 } 184 *bufp = calloc(1, 1); 185 if (*bufp == NULL) 186 return (NULL); 187 ms = malloc(sizeof(*ms)); 188 if (ms == NULL) { 189 save_errno = errno; 190 free(*bufp); 191 *bufp = NULL; 192 errno = save_errno; 193 return (NULL); 194 } 195 ms->bufp = bufp; 196 ms->sizep = sizep; 197 ms->len = 0; 198 ms->offset = 0; 199 memstream_update(ms); 200 fp = funopen(ms, NULL, memstream_write, memstream_seek, 201 memstream_close); 202 if (fp == NULL) { 203 save_errno = errno; 204 free(ms); 205 free(*bufp); 206 *bufp = NULL; 207 errno = save_errno; 208 return (NULL); 209 } 210 fwide(fp, -1); 211 return (fp); 212 } 213