1 /* 2 * Copyright (c) 2011 The Chromium OS Authors. All rights reserved. 3 * Use of this source code is governed by a BSD-style license that can be 4 * found in the LICENSE file. 5 */ 6 7 #include <stdio.h> 8 #include <string.h> 9 10 #include "fmap.h" 11 12 static int is_fmap(uint8_t *ptr) 13 { 14 FmapHeader *fmap_header = (FmapHeader *)ptr; 15 16 if (0 != memcmp(ptr, FMAP_SIGNATURE, FMAP_SIGNATURE_SIZE)) 17 return 0; 18 19 if (fmap_header->fmap_ver_major == FMAP_VER_MAJOR) 20 return 1; 21 22 fprintf(stderr, "Found FMAP, but major version is %u instead of %u\n", 23 fmap_header->fmap_ver_major, FMAP_VER_MAJOR); 24 return 0; 25 } 26 27 /* Find and point to the FMAP header within the buffer */ 28 FmapHeader *fmap_find(uint8_t *ptr, size_t size) 29 { 30 ssize_t offset, align; 31 ssize_t lim = size - sizeof(FmapHeader); 32 33 if (lim >= 0 && is_fmap(ptr)) 34 return (FmapHeader *)ptr; 35 36 /* Search large alignments before small ones to find "right" FMAP. */ 37 for (align = FMAP_SEARCH_STRIDE; align <= lim; align *= 2); 38 for (; align >= FMAP_SEARCH_STRIDE; align /= 2) 39 for (offset = align; offset <= lim; offset += align * 2) 40 if (is_fmap(ptr + offset)) 41 return (FmapHeader *)(ptr + offset); 42 43 return NULL; 44 } 45 46 /* Search for an area by name, return pointer to its beginning */ 47 uint8_t *fmap_find_by_name(uint8_t *ptr, size_t size, FmapHeader *fmap, 48 const char *name, FmapAreaHeader **ah_ptr) 49 { 50 int i; 51 FmapAreaHeader *ah; 52 53 if (!fmap) 54 fmap = fmap_find(ptr, size); 55 if (!fmap) 56 return NULL; 57 58 ah = (FmapAreaHeader*)((void *)fmap + sizeof(FmapHeader)); 59 for (i = 0; i < fmap->fmap_nareas; i++) 60 if (!strncmp(ah[i].area_name, name, FMAP_NAMELEN)) { 61 if (ah_ptr) 62 *ah_ptr = ah + i; 63 return ptr + ah[i].area_offset; 64 } 65 66 return NULL; 67 } 68
