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ba00d787f3
Now that the signal code no longer accesses it, the only real user of it was mig-reply.c, so move the logic for managing the port there. If we're in SHARED and outside of rtld, we know that __LIBC_NO_TLS () always evaluates to 0, and a TLS reply port will always be used, not __hurd_reply_port0. Still, the compiler does not see that __hurd_reply_port0 is never used due to its address being taken. To deal with this, explicitly compile out __hurd_reply_port0 when we know we won't use it. Also, instead of accessing the port via THREAD_SELF->reply_port, this uses THREAD_GETMEM and THREAD_SETMEM directly, avoiding possible miscompilations. Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
118 lines
3.6 KiB
C
118 lines
3.6 KiB
C
/* Copyright (C) 1994-2023 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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<https://www.gnu.org/licenses/>. */
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#include <mach.h>
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#include <mach/mig_support.h>
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#include <tls.h>
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/* These functions are called by MiG-generated code. */
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#if !defined (SHARED) || IS_IN (rtld)
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mach_port_t __hurd_reply_port0;
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#endif
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static mach_port_t
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get_reply_port (void)
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{
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#if !defined (SHARED) || IS_IN (rtld)
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if (__LIBC_NO_TLS ())
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return __hurd_reply_port0;
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#endif
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return THREAD_GETMEM (THREAD_SELF, reply_port);
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}
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static void
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set_reply_port (mach_port_t port)
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{
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#if !defined (SHARED) || IS_IN (rtld)
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if (__LIBC_NO_TLS ())
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__hurd_reply_port0 = port;
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else
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#endif
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THREAD_SETMEM (THREAD_SELF, reply_port, port);
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}
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/* Called by MiG to get a reply port. */
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mach_port_t
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__mig_get_reply_port (void)
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{
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mach_port_t port = get_reply_port ();
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if (__glibc_unlikely (port == MACH_PORT_NULL))
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{
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port = __mach_reply_port ();
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set_reply_port (port);
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}
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return port;
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}
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weak_alias (__mig_get_reply_port, mig_get_reply_port)
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libc_hidden_def (__mig_get_reply_port)
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/* Called by MiG to deallocate the reply port. */
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void
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__mig_dealloc_reply_port (mach_port_t arg)
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{
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error_t err;
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mach_port_t port = get_reply_port ();
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set_reply_port (MACH_PORT_NULL); /* So the mod_refs RPC won't use it. */
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/* Normally, ARG should be the same as PORT that we store. However, if a
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signal has interrupted the RPC, the stored PORT has been deallocated and
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reset to MACH_PORT_NULL (or possibly MACH_PORT_DEAD). In this case the
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MIG routine still has the old name, which it passes to us here. We must
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not deallocate (or otherwise touch) it, since it may be already allocated
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to another port right. Fortunately MIG itself doesn't do anything with
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the reply port on errors either, other than immediately calling this
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function.
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And so:
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1. Assert that things are sane, i.e. and PORT is either invalid or same
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as ARG.
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2. Only deallocate the name if our stored PORT still names it. In that
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case we're sure the right has not been deallocated / the name reused.
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*/
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if (!MACH_PORT_VALID (port))
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return;
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assert (port == arg);
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err = __mach_port_mod_refs (__mach_task_self (), port,
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MACH_PORT_RIGHT_RECEIVE, -1);
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assert_perror (err);
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}
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weak_alias (__mig_dealloc_reply_port, mig_dealloc_reply_port)
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libc_hidden_def (__mig_dealloc_reply_port)
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/* Called by mig interfaces when done with a port. Used to provide the
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same interface as needed when a custom allocator is used. */
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void
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__mig_put_reply_port(mach_port_t port)
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{
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/* Do nothing. */
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}
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weak_alias (__mig_put_reply_port, mig_put_reply_port)
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/* Called at startup with STACK == NULL. When per-thread variables are set
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up, this is called again with STACK set to the new stack being switched
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to, where per-thread variables should be set up. */
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void
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__mig_init (void *stack)
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{
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/* Do nothing. */
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}
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weak_alias (__mig_init, mig_init)
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libc_hidden_def (__mig_init)
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