1 /* ----------------------------------------------------------------------- * 2 * 3 * Copyright 2007-2008 H. Peter Anvin - All Rights Reserved 4 * 5 * Permission is hereby granted, free of charge, to any person 6 * obtaining a copy of this software and associated documentation 7 * files (the "Software"), to deal in the Software without 8 * restriction, including without limitation the rights to use, 9 * copy, modify, merge, publish, distribute, sublicense, and/or 10 * sell copies of the Software, and to permit persons to whom 11 * the Software is furnished to do so, subject to the following 12 * conditions: 13 * 14 * The above copyright notice and this permission notice shall 15 * be included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 21 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 22 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 24 * OTHER DEALINGS IN THE SOFTWARE. 25 * 26 * ----------------------------------------------------------------------- */ 27 28 /* 29 * syslinux/getadv.c 30 * 31 * Get a data item from the auxilliary data vector. Returns a pointer 32 * and sets *size on success; NULL on failure. 33 */ 34 35 #include <syslinux/adv.h> 36 #include <klibc/compiler.h> 37 #include <inttypes.h> 38 39 __export const void *syslinux_getadv(int tag, size_t * size) 40 { 41 const uint8_t *p; 42 size_t left; 43 44 p = syslinux_adv_ptr(); 45 left = syslinux_adv_size(); 46 47 while (left >= 2) { 48 uint8_t ptag = *p++; 49 size_t plen = *p++; 50 left -= 2; 51 52 if (ptag == ADV_END) 53 return NULL; /* Not found */ 54 55 if (left < plen) 56 return NULL; /* Item overrun */ 57 58 if (ptag == tag) { 59 *size = plen; 60 return p; 61 } 62 63 p += plen; 64 left -= plen; 65 } 66 67 return NULL; 68 } 69
