232 lines
8.5 KiB
C
232 lines
8.5 KiB
C
/*
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* Copyright (c) 2013, 2014 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* pthread/pthread_create.c
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* Creates a new thread.
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*/
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#include <sys/mman.h>
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#include <assert.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdalign.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 <string.h>
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#include <pthread.h>
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#include <unistd.h>
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// Utility function that rounds size upwards to a multiple of alignment.
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static size_t align_size(size_t size, size_t alignment)
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{
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return -(-size & ~(alignment-1));
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}
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__attribute__((noreturn))
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static void pthread_entrance(struct pthread* thread)
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{
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pthread_exit(thread->entry_function(thread->entry_cookie));
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}
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#if defined(__i386__) || defined(__x86_64__)
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static const unsigned long FLAGS_CARRY = 1 << 0; // 0x000001
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static const unsigned long FLAGS_RESERVED1 = 1 << 1; // 0x000002, read as one
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static const unsigned long FLAGS_PARITY = 1 << 2; // 0x000004
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static const unsigned long FLAGS_RESERVED2 = 1 << 3; // 0x000008
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static const unsigned long FLAGS_AUX = 1 << 4; // 0x000010
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static const unsigned long FLAGS_RESERVED3 = 1 << 5; // 0x000020
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static const unsigned long FLAGS_ZERO = 1 << 6; // 0x000040
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static const unsigned long FLAGS_SIGN = 1 << 7; // 0x000080
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static const unsigned long FLAGS_TRAP = 1 << 8; // 0x000100
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static const unsigned long FLAGS_INTERRUPT = 1 << 9; // 0x000200
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static const unsigned long FLAGS_DIRECTION = 1 << 10; // 0x000400
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static const unsigned long FLAGS_OVERFLOW = 1 << 11; // 0x000800
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static const unsigned long FLAGS_IOPRIVLEVEL = 1 << 12 | 1 << 13;
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static const unsigned long FLAGS_NESTEDTASK = 1 << 14; // 0x004000
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static const unsigned long FLAGS_RESERVED4 = 1 << 15; // 0x008000
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static const unsigned long FLAGS_RESUME = 1 << 16; // 0x010000
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static const unsigned long FLAGS_VIRTUAL8086 = 1 << 17; // 0x020000
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static const unsigned long FLAGS_ALIGNCHECK = 1 << 18; // 0x040000
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static const unsigned long FLAGS_VIRTINTR = 1 << 19; // 0x080000
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static const unsigned long FLAGS_VIRTINTRPEND = 1 << 20; // 0x100000
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static const unsigned long FLAGS_ID = 1 << 21; // 0x200000
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#endif
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#if defined(__i386__)
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static const unsigned long MINIMUM_STACK_SIZE = 4 * sizeof(unsigned long);
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static void setup_thread_state(struct pthread* thread, struct tfork* regs)
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{
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assert(MINIMUM_STACK_SIZE <= thread->uthread.stack_size);
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memset(regs, 0, sizeof(*regs));
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regs->eip = (uintptr_t) pthread_entrance;
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regs->eflags = FLAGS_RESERVED1 | FLAGS_INTERRUPT | FLAGS_ID;
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regs->gsbase = (unsigned long) thread;
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unsigned long* stack =
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(unsigned long*) ((uint8_t*) thread->uthread.stack_mmap +
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thread->uthread.stack_size);
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*--stack = 0; // Alignment.
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*--stack = (unsigned long) thread;
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*--stack = 0; // rip=0
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regs->esp = (uintptr_t) stack;
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regs->ebp = 0;
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}
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#endif
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#if defined(__x86_64__)
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static const unsigned long MINIMUM_STACK_SIZE = 2 * sizeof(unsigned long);
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static void setup_thread_state(struct pthread* thread, struct tfork* regs)
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{
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assert(MINIMUM_STACK_SIZE <= thread->uthread.stack_size);
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memset(regs, 0, sizeof(*regs));
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regs->rip = (uintptr_t) pthread_entrance;
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regs->rdi = (uintptr_t) thread;
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regs->rflags = FLAGS_RESERVED1 | FLAGS_INTERRUPT | FLAGS_ID;
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regs->fsbase = (unsigned long) thread;
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unsigned long* stack =
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(unsigned long*) ((uint8_t*) thread->uthread.stack_mmap +
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thread->uthread.stack_size);
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*--stack = 0; // rip=0
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regs->rsp = (uintptr_t) stack;
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regs->rbp = 0;
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}
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#endif
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int pthread_create(pthread_t* restrict thread_ptr,
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const pthread_attr_t* restrict attr,
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void* (*entry_function)(void*),
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void* restrict entry_cookie)
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{
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assert(thread_ptr);
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pthread_attr_t default_attr;
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if ( !attr )
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{
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pthread_attr_init(&default_attr);
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attr = &default_attr;
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}
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struct pthread* self = pthread_self();
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// We can't create a thread local storage copy (and thus a new thread) if
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// the kernel failed to allocate the thread local storage master copy.
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if ( self->uthread.tls_master_size && !self->uthread.tls_master_mmap )
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return errno = ENOMEM;
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size_t raw_tls_size = self->uthread.tls_master_size;
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size_t raw_tls_size_aligned = align_size(raw_tls_size, self->uthread.tls_master_align);
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if ( raw_tls_size && raw_tls_size_aligned == 0 /* overflow */ )
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return errno = EINVAL;
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size_t tls_size = raw_tls_size_aligned + sizeof(struct pthread);
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size_t tls_offset_tls = 0;
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size_t tls_offset_pthread = raw_tls_size_aligned;
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if ( self->uthread.tls_master_align < alignof(struct pthread) )
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{
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size_t more_aligned = align_size(raw_tls_size_aligned, alignof(struct pthread));
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if ( raw_tls_size_aligned && more_aligned == 0 /* overflow */ )
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return errno = EINVAL;
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size_t difference = more_aligned - raw_tls_size_aligned;
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tls_size += difference;
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tls_offset_tls += difference;
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tls_offset_pthread += difference;
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}
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assert((tls_offset_tls & (self->uthread.tls_master_align-1)) == 0);
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assert((tls_offset_pthread & (alignof(struct pthread)-1)) == 0);
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// Allocate a copy of the base thread-local storage area for use by the new
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// thread, followed by the struct pthread for the new thread.
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int prot = PROT_READ | PROT_WRITE;
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int flags = MAP_PRIVATE | MAP_ANONYMOUS;
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uint8_t* mapping = (uint8_t*) mmap(NULL, tls_size, prot, flags, -1, 0);
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if ( (void*) mapping == MAP_FAILED )
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return errno;
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// We'll put the struct pthread nicely aligned in the new mapping.
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struct pthread* thread =
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(struct pthread*) (mapping + tls_offset_pthread);
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assert((((uintptr_t) thread) & (alignof(struct pthread)-1)) == 0);
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// Let's put the thread-local storage just before the struct pthread.
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uint8_t* tls = mapping + tls_offset_tls;
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// We will now initialize the thread-local storage of the new thread.
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memcpy(tls, self->uthread.tls_master_mmap, self->uthread.tls_master_size);
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// We'll clean up the new struct pthread before initializing it.
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memset(thread, 0, sizeof(struct pthread));
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// Initialize the thread object.
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thread->uthread.uthread_pointer = &thread->uthread;
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thread->uthread.uthread_size = sizeof(struct pthread);
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thread->uthread.uthread_flags = 0;
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thread->uthread.tls_master_mmap = self->uthread.tls_master_mmap;
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thread->uthread.tls_master_size = self->uthread.tls_master_size;
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thread->uthread.tls_master_align = self->uthread.tls_master_align;
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thread->uthread.tls_mmap = mapping;
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thread->uthread.tls_size = tls_size;
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thread->uthread.arg_mmap = self->uthread.arg_mmap;
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thread->uthread.arg_size = self->uthread.arg_size;
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thread->join_lock = (pthread_mutex_t) PTHREAD_NORMAL_MUTEX_INITIALIZER_NP;
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thread->join_lock.lock = 1 /* LOCKED_VALUE */;
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thread->join_lock.type = PTHREAD_MUTEX_NORMAL;
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thread->join_lock.owner = (unsigned long) thread;
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thread->detach_lock = (pthread_mutex_t) PTHREAD_NORMAL_MUTEX_INITIALIZER_NP;
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thread->detach_state = attr->detach_state;
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thread->entry_function = entry_function;
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thread->entry_cookie = entry_cookie;
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// Set up a stack for the new thread.
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int stack_prot = PROT_READ | PROT_WRITE;
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int stack_flags = MAP_PRIVATE | MAP_ANONYMOUS;
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thread->uthread.stack_size = attr->stack_size;
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thread->uthread.stack_mmap =
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mmap(NULL, thread->uthread.stack_size, stack_prot, stack_flags, -1, 0);
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if ( thread->uthread.stack_mmap == MAP_FAILED )
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{
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munmap(thread->uthread.tls_mmap, thread->uthread.tls_size);
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return errno;
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}
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// Prepare the registers and initial stack for the new thread.
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struct tfork regs;
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setup_thread_state(thread, ®s);
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memset(®s.altstack, 0, sizeof(regs.altstack));
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regs.altstack.ss_flags = SS_DISABLE;
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sigprocmask(SIG_SETMASK, NULL, ®s.sigmask);
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// Create a new thread with the requested state.
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if ( tfork(SFTHREAD, ®s) < 0 )
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{
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munmap(thread->uthread.stack_mmap, thread->uthread.stack_size);
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munmap(thread->uthread.tls_mmap, thread->uthread.tls_size);
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return errno;
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}
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*thread_ptr = thread;
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return 0;
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}
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