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-rw-r--r--ext/libelf/libelf_xlate.c141
1 files changed, 141 insertions, 0 deletions
diff --git a/ext/libelf/libelf_xlate.c b/ext/libelf/libelf_xlate.c
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+/*-
+ * Copyright (c) 2006 Joseph Koshy
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <assert.h>
+
+#include "libelf.h"
+#include "_libelf.h"
+
+/*
+ * Translate to/from the file representation of ELF objects.
+ *
+ * Translation could potentially involve the following
+ * transformations:
+ *
+ * - an endianness conversion,
+ * - a change of layout, as the file representation of ELF objects
+ * can differ from their in-memory representation.
+ * - a change in representation due to a layout version change.
+ */
+
+Elf_Data *
+_libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding,
+ int elfclass, int direction)
+{
+ size_t cnt, dsz, fsz, msz;
+ uintptr_t sb, se, db, de;
+
+ if (encoding == ELFDATANONE)
+ encoding = LIBELF_PRIVATE(byteorder);
+
+ if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) ||
+ dst == NULL || src == NULL || dst == src) {
+ LIBELF_SET_ERROR(ARGUMENT, 0);
+ return (NULL);
+ }
+
+ assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
+ assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY);
+
+ if (dst->d_version != src->d_version) {
+ LIBELF_SET_ERROR(UNIMPL, 0);
+ return (NULL);
+ }
+
+ if (src->d_buf == NULL || dst->d_buf == NULL ||
+ src->d_size == 0) {
+ LIBELF_SET_ERROR(DATA, 0);
+ return (NULL);
+ }
+
+ if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) {
+ LIBELF_SET_ERROR(DATA, 0);
+ return (NULL);
+ }
+
+ if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)(src->d_type,
+ (size_t) 1, src->d_version)) == 0)
+ return (NULL);
+
+ msz = _libelf_msize(src->d_type, elfclass, src->d_version);
+
+ assert(msz > 0);
+
+ if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) {
+ LIBELF_SET_ERROR(DATA, 0);
+ return (NULL);
+ }
+
+ /*
+ * Determine the number of objects that need to be converted, and
+ * the space required for the converted objects in the destination
+ * buffer.
+ */
+ if (direction == ELF_TOMEMORY) {
+ cnt = src->d_size / fsz;
+ dsz = cnt * msz;
+ } else {
+ cnt = src->d_size / msz;
+ dsz = cnt * fsz;
+ }
+
+ if (dst->d_size < dsz) {
+ LIBELF_SET_ERROR(DATA, 0);
+ return (NULL);
+ }
+
+ sb = (uintptr_t) src->d_buf;
+ se = sb + src->d_size;
+ db = (uintptr_t) dst->d_buf;
+ de = db + dst->d_size;
+
+ /*
+ * Check for overlapping buffers. Note that db == sb is
+ * allowed.
+ */
+ if (db != sb && de > sb && se > db) {
+ LIBELF_SET_ERROR(DATA, 0);
+ return (NULL);
+ }
+
+ if ((direction == ELF_TOMEMORY ? db : sb) %
+ _libelf_malign(src->d_type, elfclass)) {
+ LIBELF_SET_ERROR(DATA, 0);
+ return (NULL);
+ }
+
+ dst->d_type = src->d_type;
+ dst->d_size = dsz;
+
+ if (db == sb && encoding == LIBELF_PRIVATE(byteorder) &&
+ fsz == msz)
+ return (dst); /* nothing more to do */
+
+ (_libelf_get_translator(src->d_type, direction, elfclass))(dst->d_buf,
+ src->d_buf, cnt, encoding != LIBELF_PRIVATE(byteorder));
+
+ return (dst);
+}