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82eef55f8f
This commit adds a new _dl_open_hook entry for dlvsym and implements the function using the existing dl_lookup_symbol_x function supplied by the dynamic loader. A new hook variable, _dl_open_hook2, is introduced, which should make this change suitable for backporting: For old statically linked binaries, __libc_dlvsym will always return NULL.
126 lines
4.3 KiB
C
126 lines
4.3 KiB
C
/* Compare dlvsym and __libc_dlvsym results. Common code.
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Copyright (C) 2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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/* compare_vsyms is the main entry point for these tests.
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Indirectly, It calls __libc_dlvsym (from libc.so; internal
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interface) and dlvsym (from libdl.so; public interface) to compare
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the results for a selected set of symbols in libc.so which
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typically have more than one symbol version. The two functions are
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implemented by somewhat different code, and this test checks that
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their results are the same.
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The versions are generated to range from GLIBC_2.0 to GLIBC_2.Y,
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with Y being the current __GLIBC_MINOR__ version plus two. In
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addition, there is a list of special symbol versions of the form
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GLIBC_2.Y.Z, which were used for some releases.
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Comparing the two dlvsym results at versions which do not actually
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exist does not test much, but it will not contribute to false test
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failures, either. */
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#include <array_length.h>
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#include <gnu/lib-names.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <support/check.h>
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#include <support/xdlfcn.h>
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/* Run consistency check for versioned symbol NAME@VERSION. NB: We
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may execute in a shared object, so exit on error for proper error
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reporting. */
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static void
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compare_vsyms_0 (void *libc_handle, const char *name, const char *version,
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bool *pfound)
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{
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void *dlvsym_address = dlvsym (libc_handle, name, version);
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void *libc_dlvsym_address
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= __libc_dlvsym (libc_handle, name, version);
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if (dlvsym_address != libc_dlvsym_address)
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FAIL_EXIT1 ("%s@%s mismatch: %p != %p",
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name, version, dlvsym_address, libc_dlvsym_address);
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if (dlvsym_address != NULL)
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*pfound = true;
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}
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/* Run consistency check for versioned symbol NAME at multiple symbol
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version. */
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static void
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compare_vsyms_1 (void *libc_handle, const char *name)
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{
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bool found = false;
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/* Historic versions which do not follow the usual GLIBC_2.Y
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pattern, to increase test coverage. Not all architectures have
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those, but probing additional versions does not hurt. */
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static const char special_versions[][12] =
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{
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"GLIBC_2.1.1",
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"GLIBC_2.1.2",
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"GLIBC_2.1.3",
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"GLIBC_2.1.4",
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"GLIBC_2.2.1",
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"GLIBC_2.2.2",
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"GLIBC_2.2.3",
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"GLIBC_2.2.4",
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"GLIBC_2.2.5",
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"GLIBC_2.2.6",
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"GLIBC_2.3.2",
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"GLIBC_2.3.3",
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"GLIBC_2.3.4",
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};
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for (int i = 0; i < array_length (special_versions); ++i)
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compare_vsyms_0 (libc_handle, name, special_versions[i], &found);
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/* Iterate to an out-of-range version, to cover some unused symbols
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as well. */
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for (int minor_version = 0; minor_version <= __GLIBC_MINOR__ + 2;
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++minor_version)
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{
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char version[30];
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snprintf (version, sizeof (version), "GLIBC_%d.%d",
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__GLIBC__, minor_version);
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compare_vsyms_0 (libc_handle, name, version, &found);
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}
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if (!found)
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FAIL_EXIT1 ("symbol %s not found at any version", name);
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}
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/* Run consistency checks for various symbols which usually have
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multiple versions. */
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static void
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compare_vsyms (void)
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{
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/* The minor version loop in compare_vsyms_1 needs updating in case
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we ever switch to glibc 3.0. */
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if (__GLIBC__ != 2)
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FAIL_EXIT1 ("unexpected glibc major version: %d", __GLIBC__);
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/* __libc_dlvsym does not recognize the special RTLD_* handles, so
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obtain an explicit handle for libc.so. */
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void *libc_handle = xdlopen (LIBC_SO, RTLD_LAZY | RTLD_NOLOAD);
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compare_vsyms_1 (libc_handle, "_sys_errlist");
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compare_vsyms_1 (libc_handle, "_sys_siglist");
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compare_vsyms_1 (libc_handle, "quick_exit");
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xdlclose (libc_handle);
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}
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