c6736a59b3
for the initial stack, just change the initial thread's pt_uc to point to the opposite end of the stack (away from the argv, environment, etc).
224 lines
6.6 KiB
C
224 lines
6.6 KiB
C
/* $NetBSD: pthread_stack.c,v 1.16 2004/08/17 14:16:00 chs Exp $ */
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/*-
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* Copyright (c) 2001 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Nathan J. Williams.
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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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* 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: pthread_stack.c,v 1.16 2004/08/17 14:16:00 chs Exp $");
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#define __EXPOSE_STACK 1
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#include <sys/param.h>
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#include <err.h>
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#include <errno.h>
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#include <signal.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <ucontext.h>
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#include <unistd.h>
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#include <sys/queue.h>
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#include <sys/mman.h>
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#include <sys/resource.h>
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#include <sched.h>
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#include "pthread.h"
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#include "pthread_int.h"
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static pthread_t
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pthread__stackid_setup(void *base, size_t size);
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#ifndef PT_FIXEDSTACKSIZE_LG
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/*
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* We have to initialize the pthread_stack* variables here because
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* mutexes are used before pthread_init() and thus pthread__initmain()
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* are called. Since mutexes only save the stack pointer and not a
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* pointer to the thread data, it is safe to change the mapping from
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* stack pointer to thread data afterwards.
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*/
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#define _STACKSIZE_LG 18
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int pthread_stacksize_lg = _STACKSIZE_LG;
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size_t pthread_stacksize = 1 << _STACKSIZE_LG;
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vaddr_t pthread_stackmask = (1 << _STACKSIZE_LG) - 1;
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#undef _STACKSIZE_LG
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#endif /* !PT_FIXEDSTACKSIZE_LG */
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/*
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* Allocate a stack for a thread, and set it up. It needs to be aligned, so
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* that a thread can find itself by its stack pointer.
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*/
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int
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pthread__stackalloc(pthread_t *newt)
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{
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void *addr;
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addr = mmap(NULL, PT_STACKSIZE, PROT_READ|PROT_WRITE,
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MAP_ANON|MAP_PRIVATE | MAP_ALIGNED(PT_STACKSIZE_LG), -1, (off_t)0);
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if (addr == MAP_FAILED)
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return ENOMEM;
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pthread__assert(((intptr_t)addr & PT_STACKMASK) == 0);
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*newt = pthread__stackid_setup(addr, PT_STACKSIZE);
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return 0;
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}
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/*
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* Set up the slightly special stack for the "initial" thread, which
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* runs on the normal system stack, and thus gets slightly different
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* treatment.
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*/
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void
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pthread__initmain(pthread_t *newt)
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{
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pthread_t t;
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void *base;
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size_t size;
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#ifndef PT_FIXEDSTACKSIZE_LG
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struct rlimit slimit;
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size_t pagesize;
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char *value;
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int ret;
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pagesize = (size_t)sysconf(_SC_PAGESIZE);
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pthread_stacksize = 0;
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ret = getrlimit(RLIMIT_STACK, &slimit);
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if (ret == -1)
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err(1, "Couldn't get stack resource consumption limits");
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value = getenv("PTHREAD_STACKSIZE");
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if (value) {
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pthread_stacksize = atoi(value) * 1024;
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if (pthread_stacksize > slimit.rlim_cur)
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pthread_stacksize = (size_t)slimit.rlim_cur;
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}
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if (pthread_stacksize == 0)
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pthread_stacksize = (size_t)slimit.rlim_cur;
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if (pthread_stacksize < 4 * pagesize)
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errx(1, "Stacksize limit is too low, minimum %zd kbyte.",
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4 * pagesize / 1024);
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pthread_stacksize_lg = -1;
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while (pthread_stacksize) {
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pthread_stacksize >>= 1;
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pthread_stacksize_lg++;
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}
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pthread_stacksize = (1 << pthread_stacksize_lg);
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pthread_stackmask = pthread_stacksize - 1;
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#endif /* PT_FIXEDSTACKSIZE_LG */
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base = (void *)(pthread__sp() & ~PT_STACKMASK);
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size = PT_STACKSIZE;
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t = pthread__stackid_setup(base, size);
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/*
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* The "safe" area chosen below isn't safe for the initial thread stack
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* because we don't control the end of the stack.
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* For example, on i386 the stack usually ends at 0xbfc00000,
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* so for requested sizes >=8MB, the last 4MB of stack isn't available.
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* Also, we don't want to clobber the argv, environment, etc.
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* Reset the initial pt_uc pointer to be safe for the initial thread.
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*/
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#ifdef __MACHINE_STACK_GROWS_UP
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t->pt_uc = (ucontext_t *)
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((char *)t->pt_stack.ss_sp + t->pt_stack.ss_size -
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sizeof (ucontext_t));
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#else
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t->pt_uc = (ucontext_t *)t->pt_stack.ss_sp;
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#endif
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*newt = t;
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}
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static pthread_t
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/*ARGSUSED*/
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pthread__stackid_setup(void *base, size_t size)
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{
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pthread_t t;
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void *redaddr;
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size_t pagesize;
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caddr_t sp;
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int ret;
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t = base;
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pagesize = (size_t)sysconf(_SC_PAGESIZE);
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/*
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* Put a pointer to the pthread in the bottom (but
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* redzone-protected section) of the stack.
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*/
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redaddr = STACK_SHRINK(STACK_MAX(base, size), pagesize);
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t->pt_stack.ss_size = size - 2 * pagesize;
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#ifdef __MACHINE_STACK_GROWS_UP
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t->pt_stack.ss_sp = (char *)base + pagesize;
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sp = t->pt_stack.ss_sp;
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#else
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t->pt_stack.ss_sp = (char *)base + 2 * pagesize;
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sp = (caddr_t)t->pt_stack.ss_sp + t->pt_stack.ss_size;
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#endif
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/* Set up an initial ucontext pointer to a "safe" area */
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t->pt_uc = (ucontext_t *)
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STACK_ALIGN(STACK_GROW(sp, pagesize / 2), ~_UC_UCONTEXT_ALIGN);
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/* Protect the next-to-bottom stack page as a red zone. */
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ret = mprotect(redaddr, pagesize, PROT_NONE);
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if (ret == -1)
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err(2, "Couldn't mprotect() stack redzone at %p\n", redaddr);
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return t;
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}
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ssize_t
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pthread__stackinfo_offset()
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{
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size_t pagesize;
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pagesize = (size_t)sysconf(_SC_PAGESIZE);
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#ifdef __MACHINE_STACK_GROWS_UP
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return (-pagesize + offsetof(struct __pthread_st, pt_stackinfo));
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#else
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return (-(2 * pagesize) + offsetof(struct __pthread_st, pt_stackinfo));
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#endif
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}
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