aeb757d841
solved by a simple 'make world'. The signalcontext function was going to the trouble of generating an even 16 byte alignment, but in fact it needed to be odd aligned to simulate the 8-byte return address having been pushed by the caller. This fixes yet another group of crashes in applications using libpthread. And yet again, it was my fault all along. While here, rename the duplicate internal ctx_wrapper() functions to makectx_wrapper() and sigctx_wrapper() so that traces aren't ambiguous.
105 lines
3.3 KiB
C
105 lines
3.3 KiB
C
/*
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* Copyright (c) 2003 Marcel Moolenaar
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/ucontext.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <strings.h>
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typedef void (*handler_t)(uint64_t, uint64_t, uint64_t);
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/* Prototypes */
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static void sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args);
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__weak_reference(__signalcontext, signalcontext);
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int
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__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func)
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{
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uint64_t *args;
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siginfo_t *sig_si;
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ucontext_t *sig_uc;
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uint64_t sp;
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/* Bail out if we don't have a valid ucontext pointer. */
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if (ucp == NULL)
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abort();
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/*
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* Build a signal frame and copy the arguments of signal handler
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* 'func' onto the stack and do the funky stack alignment.
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* This means that we need an 8-byte-odd alignment since the ABI expects
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* the return address to be pushed, thus breaking the 16 byte alignment.
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*/
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sp = (ucp->uc_mcontext.mc_rsp - sizeof(ucontext_t)) & ~15UL;
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sig_uc = (ucontext_t *)sp;
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bcopy(ucp, sig_uc, sizeof(*sig_uc));
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sp = (sp - sizeof(siginfo_t)) & ~15UL;
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sig_si = (siginfo_t *)sp;
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bzero(sig_si, sizeof(*sig_si));
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sig_si->si_signo = sig;
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sp -= 3 * sizeof(uint64_t);
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args = (uint64_t *)sp;
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args[0] = sig;
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args[1] = (intptr_t)sig_si;
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args[2] = (intptr_t)sig_uc;
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sp -= 16;
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/*
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* Setup the ucontext of the signal handler.
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*/
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bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext));
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ucp->uc_link = sig_uc;
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sigdelset(&ucp->uc_sigmask, sig);
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ucp->uc_mcontext.mc_len = sizeof(mcontext_t);
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ucp->uc_mcontext.mc_rdi = (register_t)ucp;
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ucp->uc_mcontext.mc_rsi = (register_t)func;
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ucp->uc_mcontext.mc_rdx = (register_t)args;
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ucp->uc_mcontext.mc_rbp = (register_t)sp;
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ucp->uc_mcontext.mc_rbx = (register_t)sp;
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ucp->uc_mcontext.mc_rsp = (register_t)sp;
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ucp->uc_mcontext.mc_rip = (register_t)sigctx_wrapper;
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return (0);
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}
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static void
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sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args)
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{
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(*func)(args[0], args[1], args[2]);
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if (ucp->uc_link == NULL)
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exit(0);
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setcontext((const ucontext_t *)ucp->uc_link);
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/* should never get here */
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abort();
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/* NOTREACHED */
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}
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