68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
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/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include "fmap.h"
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static int is_fmap(uint8_t *ptr)
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{
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FmapHeader *fmap_header = (FmapHeader *)ptr;
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if (0 != memcmp(ptr, FMAP_SIGNATURE, FMAP_SIGNATURE_SIZE))
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return 0;
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if (fmap_header->fmap_ver_major == FMAP_VER_MAJOR)
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return 1;
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fprintf(stderr, "Found FMAP, but major version is %u instead of %u\n",
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fmap_header->fmap_ver_major, FMAP_VER_MAJOR);
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return 0;
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}
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/* Find and point to the FMAP header within the buffer */
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FmapHeader *fmap_find(uint8_t *ptr, size_t size)
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{
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ssize_t offset, align;
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ssize_t lim = size - sizeof(FmapHeader);
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if (lim >= 0 && is_fmap(ptr))
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return (FmapHeader *)ptr;
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/* Search large alignments before small ones to find "right" FMAP. */
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for (align = FMAP_SEARCH_STRIDE; align <= lim; align *= 2);
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for (; align >= FMAP_SEARCH_STRIDE; align /= 2)
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for (offset = align; offset <= lim; offset += align * 2)
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if (is_fmap(ptr + offset))
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return (FmapHeader *)(ptr + offset);
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return NULL;
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}
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/* Search for an area by name, return pointer to its beginning */
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uint8_t *fmap_find_by_name(uint8_t *ptr, size_t size, FmapHeader *fmap,
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const char *name, FmapAreaHeader **ah_ptr)
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{
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int i;
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FmapAreaHeader *ah;
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if (!fmap)
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fmap = fmap_find(ptr, size);
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if (!fmap)
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return NULL;
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ah = (FmapAreaHeader*)((void *)fmap + sizeof(FmapHeader));
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for (i = 0; i < fmap->fmap_nareas; i++)
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if (!strncmp(ah[i].area_name, name, FMAP_NAMELEN)) {
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if (ah_ptr)
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*ah_ptr = ah + i;
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return ptr + ah[i].area_offset;
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}
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return NULL;
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}
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