platform_bionic/tests/libs/elftls_dynamic.cpp
Ryan Prichard e4d620bc80 Fix dlsym and dladdr for TLS symbols
* dlsym: call __tls_get_addr for TLS symbols

 * dladdr: skip TLS symbols

Bug: b/123772574
Test: bionic unit tests
Change-Id: I59a8bc4a7d455e1018b0d577b027b6417c8487cd
2019-04-03 18:19:50 -07:00

73 lines
2.9 KiB
C++

/*
* Copyright (C) 2019 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
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* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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*/
// This shared object test library is dlopen'ed by the main test executable.
// Export a large TLS variable from a solib for testing dladdr and dlsym. The
// TLS symbol's value will appear to overlap almost everything else in the
// shared object, but dladdr must not return it.
__thread char large_tls_var[4 * 1024 * 1024];
extern "C" char* get_large_tls_var_addr() {
return large_tls_var;
}
// For testing dladdr, return an address that's part of the solib's .bss
// section, but does not have an entry in the dynsym table and whose
// solib-relative address appears to overlap with the large TLS variable.
extern "C" void* get_local_addr() {
static char dummy[1024];
return &dummy[512];
}
// This variable comes from libtest_elftls_shared_var.so, which is part of
// static TLS. Verify that a GD-model access can access the variable.
//
// Accessing the static TLS variable from an solib prevents the static linker
// from relaxing the GD access to IE and lets us test that __tls_get_addr and
// the tlsdesc resolver handle a static TLS variable.
extern "C" __thread int elftls_shared_var;
extern "C" int bump_shared_var() {
return ++elftls_shared_var;
}
// The static linker denotes the current module by omitting the symbol from
// the DTPMOD/TLSDESC relocations.
static __thread int local_var_1 = 15;
static __thread int local_var_2 = 25;
extern "C" int bump_local_vars() {
return ++local_var_1 + ++local_var_2;
}
__attribute__((weak)) extern "C" __thread int missing_weak_dyn_tls;
extern "C" int* missing_weak_dyn_tls_addr() {
return &missing_weak_dyn_tls;
}