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97 lines
3.4 KiB
97 lines
3.4 KiB
/* |
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* Copyright (C) 2008, 2009 The Android Open Source Project |
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* All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* * Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* * Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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#if defined __ANDROID__ && !defined XASH_64BIT |
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#include <android/log.h> |
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#include "linker.h" |
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static Elf_Sym* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) { |
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Elf_Sym* symtab = si->symtab; |
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const char* strtab = si->strtab; |
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if( si->nbucket == 0 ) |
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return NULL; |
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for (unsigned n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]) { |
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Elf_Sym* s = symtab + n; |
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if (strcmp(strtab + s->st_name, name)) continue; |
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/* only concern ourselves with global and weak symbol definitions */ |
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switch (ELF_ST_BIND(s->st_info)) { |
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case STB_GLOBAL: |
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case STB_WEAK: |
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if (s->st_shndx == SHN_UNDEF) { |
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continue; |
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} |
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return s; |
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} |
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} |
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return NULL; |
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} |
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static unsigned elfhash(const char* _name) { |
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const unsigned char* name = (const unsigned char*) _name; |
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unsigned h = 0, g; |
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while(*name) { |
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h = (h << 4) + *name++; |
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g = h & 0xf0000000; |
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h ^= g; |
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h ^= g >> 24; |
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} |
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return h; |
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} |
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/* This is used by dlsym(3). It performs symbol lookup only within the |
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specified soinfo object and not in any of its dependencies. |
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TODO: Only looking in the specified soinfo seems wrong. dlsym(3) says |
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that it should do a breadth first search through the dependency |
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tree. This agrees with the ELF spec (aka System V Application |
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Binary Interface) where in Chapter 5 it discuss resolving "Shared |
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Object Dependencies" in breadth first search order. |
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*/ |
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static Elf_Sym* dlsym_handle_lookup(soinfo* si, const char* name) { |
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return soinfo_elf_lookup(si, elfhash(name), name); |
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} |
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extern "C" void* dlsym_weak(void* handle, const char* symbol) { |
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soinfo* found = NULL; |
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Elf_Sym* sym = NULL; |
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found = reinterpret_cast<soinfo*>(handle); |
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sym = dlsym_handle_lookup(found, symbol); |
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if (sym != NULL) { |
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return reinterpret_cast<void*>(sym->st_value + found->base/*load_bias*/); |
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} |
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__android_log_print(ANDROID_LOG_ERROR, "dlsym-weak", "Failed when looking up %s\n", symbol); |
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return NULL; |
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} |
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#endif
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