2827ab990a
The __libc_freeres framework does not extend to non-libc.so objects. This causes problems in general for valgrind and mtrace detecting unfreed objects in both libdl.so and libpthread.so. This change is a pre-requisite to properly moving the malloc hooks out of malloc since such a move now requires precise accounting of all allocated data before destructors are run. This commit adds a proper hook in libc.so.6 for both libdl.so and for libpthread.so, this ensures that shm-directory.c which uses freeit () to free memory is called properly. We also remove the nptl_freeres hook and fall back to using weak-ref-and-check idiom for a loaded libpthread.so, thus making this process similar for all DSOs. Lastly we follow best practice and use explicit free calls for both libdl.so and libpthread.so instead of the generic hook process which has undefined order. Tested on x86_64 with no regressions. Signed-off-by: DJ Delorie <dj@redhat.com> Signed-off-by: Carlos O'Donell <carlos@redhat.com>
150 lines
4.3 KiB
C
150 lines
4.3 KiB
C
/* Copyright (C) 2003-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Jakub Jelinek <jakub@redhat.com>.
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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 License as
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published by the Free Software Foundation; either version 2.1 of the
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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; see the file COPYING.LIB. If
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not, see <http://www.gnu.org/licenses/>. */
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#include <dlfcn.h>
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#include <stdio.h>
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#include <unwind.h>
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#include <pthreadP.h>
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#include <sysdep.h>
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#include <gnu/lib-names.h>
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#include <unwind-resume.h>
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static void *libgcc_s_handle;
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void (*__libgcc_s_resume) (struct _Unwind_Exception *exc)
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attribute_hidden __attribute__ ((noreturn));
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static _Unwind_Reason_Code (*libgcc_s_personality) PERSONALITY_PROTO;
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static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
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(struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
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static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
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void
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__attribute_noinline__
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pthread_cancel_init (void)
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{
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void *resume;
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void *personality;
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void *forcedunwind;
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void *getcfa;
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void *handle;
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if (__glibc_likely (libgcc_s_handle != NULL))
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{
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/* Force gcc to reload all values. */
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asm volatile ("" ::: "memory");
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return;
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}
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/* See include/dlfcn.h. Use of __libc_dlopen requires RTLD_NOW. */
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handle = __libc_dlopen (LIBGCC_S_SO);
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if (handle == NULL
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|| (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
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|| (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
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|| (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
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== NULL
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|| (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
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#ifdef ARCH_CANCEL_INIT
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|| ARCH_CANCEL_INIT (handle)
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#endif
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)
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__libc_fatal (LIBGCC_S_SO " must be installed for pthread_cancel to work\n");
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PTR_MANGLE (resume);
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__libgcc_s_resume = resume;
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PTR_MANGLE (personality);
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libgcc_s_personality = personality;
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PTR_MANGLE (forcedunwind);
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libgcc_s_forcedunwind = forcedunwind;
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PTR_MANGLE (getcfa);
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libgcc_s_getcfa = getcfa;
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/* Make sure libgcc_s_handle is written last. Otherwise,
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pthread_cancel_init might return early even when the pointer the
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caller is interested in is not initialized yet. */
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atomic_write_barrier ();
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libgcc_s_handle = handle;
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}
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/* Register for cleanup in libpthread.so. */
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void
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__nptl_unwind_freeres (void)
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{
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void *handle = libgcc_s_handle;
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if (handle != NULL)
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{
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libgcc_s_handle = NULL;
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__libc_dlclose (handle);
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}
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}
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#if !HAVE_ARCH_UNWIND_RESUME
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void
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_Unwind_Resume (struct _Unwind_Exception *exc)
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{
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if (__glibc_unlikely (libgcc_s_handle == NULL))
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pthread_cancel_init ();
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else
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atomic_read_barrier ();
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void (*resume) (struct _Unwind_Exception *exc) = __libgcc_s_resume;
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PTR_DEMANGLE (resume);
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resume (exc);
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}
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#endif
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_Unwind_Reason_Code
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__gcc_personality_v0 PERSONALITY_PROTO
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{
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if (__glibc_unlikely (libgcc_s_handle == NULL))
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pthread_cancel_init ();
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else
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atomic_read_barrier ();
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__typeof (libgcc_s_personality) personality = libgcc_s_personality;
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PTR_DEMANGLE (personality);
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return (*personality) PERSONALITY_ARGS;
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}
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_Unwind_Reason_Code
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_Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
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void *stop_argument)
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{
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if (__glibc_unlikely (libgcc_s_handle == NULL))
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pthread_cancel_init ();
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else
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atomic_read_barrier ();
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_Unwind_Reason_Code (*forcedunwind)
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(struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)
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= libgcc_s_forcedunwind;
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PTR_DEMANGLE (forcedunwind);
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return forcedunwind (exc, stop, stop_argument);
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}
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_Unwind_Word
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_Unwind_GetCFA (struct _Unwind_Context *context)
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{
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if (__glibc_unlikely (libgcc_s_handle == NULL))
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pthread_cancel_init ();
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else
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atomic_read_barrier ();
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_Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;
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PTR_DEMANGLE (getcfa);
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return getcfa (context);
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}
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