1 /* $NetBSD: store_emem.c,v 1.3 2023/06/19 21:41:44 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1997 - 2002 Kungliga Tekniska Hgskolan 5 * (Royal Institute of Technology, Stockholm, Sweden). 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 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * 3. Neither the name of the Institute nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include "krb5_locl.h" 37 #include "store-int.h" 38 39 typedef struct emem_storage{ 40 unsigned char *base; 41 size_t size; 42 size_t len; 43 unsigned char *ptr; 44 }emem_storage; 45 46 static ssize_t 47 emem_fetch(krb5_storage *sp, void *data, size_t size) 48 { 49 emem_storage *s = (emem_storage*)sp->data; 50 if((size_t)(s->base + s->len - s->ptr) < size) 51 size = s->base + s->len - s->ptr; 52 memmove(data, s->ptr, size); 53 sp->seek(sp, size, SEEK_CUR); 54 return size; 55 } 56 57 static ssize_t 58 emem_store(krb5_storage *sp, const void *data, size_t size) 59 { 60 emem_storage *s = (emem_storage*)sp->data; 61 if(size > (size_t)(s->base + s->size - s->ptr)){ 62 void *base; 63 size_t sz, off; 64 off = s->ptr - s->base; 65 sz = off + size; 66 if (sz < 4096) 67 sz *= 2; 68 base = realloc(s->base, sz); 69 if(base == NULL) 70 return -1; 71 s->size = sz; 72 s->base = base; 73 s->ptr = (unsigned char*)base + off; 74 } 75 if (size) 76 memmove(s->ptr, data, size); 77 sp->seek(sp, size, SEEK_CUR); 78 return size; 79 } 80 81 static off_t 82 emem_seek(krb5_storage *sp, off_t offset, int whence) 83 { 84 emem_storage *s = (emem_storage*)sp->data; 85 switch(whence){ 86 case SEEK_SET: 87 if((size_t)offset > s->size) 88 offset = s->size; 89 if(offset < 0) 90 offset = 0; 91 s->ptr = s->base + offset; 92 if((size_t)offset > s->len) 93 s->len = offset; 94 break; 95 case SEEK_CUR: 96 sp->seek(sp,s->ptr - s->base + offset, SEEK_SET); 97 break; 98 case SEEK_END: 99 sp->seek(sp, s->len + offset, SEEK_SET); 100 break; 101 default: 102 errno = EINVAL; 103 return -1; 104 } 105 return s->ptr - s->base; 106 } 107 108 static int 109 emem_trunc(krb5_storage *sp, off_t offset) 110 { 111 emem_storage *s = (emem_storage*)sp->data; 112 /* 113 * If offset is larget then current size, or current size is 114 * shrunk more then half of the current size, adjust buffer. 115 */ 116 if (offset == 0) { 117 free(s->base); 118 s->size = 0; 119 s->base = NULL; 120 s->ptr = NULL; 121 } else if ((size_t)offset > s->size || (s->size / 2) > (size_t)offset) { 122 void *base; 123 size_t off; 124 off = s->ptr - s->base; 125 base = realloc(s->base, offset); 126 if(base == NULL) 127 return ENOMEM; 128 if ((size_t)offset > s->size) 129 memset((char *)base + s->size, 0, offset - s->size); 130 s->size = offset; 131 s->base = base; 132 s->ptr = (unsigned char *)base + off; 133 } 134 s->len = offset; 135 if ((s->ptr - s->base) > offset) 136 s->ptr = s->base + offset; 137 return 0; 138 } 139 140 141 static void 142 emem_free(krb5_storage *sp) 143 { 144 emem_storage *s = sp->data; 145 memset(s->base, 0, s->len); 146 free(s->base); 147 } 148 149 /** 150 * Create a elastic (allocating) memory storage backend. Memory is 151 * allocated on demand. Free returned krb5_storage with 152 * krb5_storage_free(). 153 * 154 * @return A krb5_storage on success, or NULL on out of memory error. 155 * 156 * @ingroup krb5_storage 157 * 158 * @sa krb5_storage_from_mem() 159 * @sa krb5_storage_from_readonly_mem() 160 * @sa krb5_storage_from_fd() 161 * @sa krb5_storage_from_data() 162 * @sa krb5_storage_from_socket() 163 */ 164 165 KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL 166 krb5_storage_emem(void) 167 { 168 krb5_storage *sp; 169 emem_storage *s; 170 171 sp = malloc(sizeof(krb5_storage)); 172 if (sp == NULL) 173 return NULL; 174 175 s = malloc(sizeof(*s)); 176 if (s == NULL) { 177 free(sp); 178 return NULL; 179 } 180 sp->data = s; 181 sp->flags = 0; 182 sp->eof_code = HEIM_ERR_EOF; 183 s->size = 1024; 184 s->base = malloc(s->size); 185 if (s->base == NULL) { 186 free(sp); 187 free(s); 188 return NULL; 189 } 190 s->len = 0; 191 s->ptr = s->base; 192 sp->fetch = emem_fetch; 193 sp->store = emem_store; 194 sp->seek = emem_seek; 195 sp->trunc = emem_trunc; 196 sp->fsync = NULL; 197 sp->free = emem_free; 198 sp->max_alloc = UINT_MAX/8; 199 return sp; 200 } 201
Indexes created Wed Mar 18 00:23:26 UTC 2026