xref: /aosp_15_r20/bionic/tests/libs/elftls_dynamic.cpp (revision 8d67ca893c1523eb926b9080dbe4e2ffd2a27ba1)

/*
 * 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
 *    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 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
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * 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 buf[1024];
  return &buf[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;
}

extern "C" int get_local_var1() {
  return local_var_1;
}

extern "C" int* get_local_var1_addr() {
  return &local_var_1;
}

extern "C" int get_local_var2() {
  return 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;
}