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2003-07-22 Jakub Jelinek <jakub@redhat.com> * include/resolv.h (__resp): Declare. Define to __libc_resp if in libc.so. (_res): If USE___THREAD, define to (*__resp). * resolv/res_libc.c (_res): Normal .bss variable with compat_symbol even if USE___THREAD. (__resp): New __thread variable. (__libc_resp): New alias. * resolv/Versions (libc): Export _res@GLIBC_2.0 even if USE_TLS && HAVE___THREAD. Export __resp@@GLIBC_PRIVATE. * sysdeps/generic/res-state.c (__res_state): Return __resp if USE___THREAD.
267 lines
10 KiB
C
267 lines
10 KiB
C
/* Linuxthreads - a simple clone()-based implementation of Posix */
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/* threads for Linux. */
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/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
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/* */
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/* This program is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU Library General Public License */
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/* as published by the Free Software Foundation; either version 2 */
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/* of the License, or (at your option) any later version. */
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/* */
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/* This program 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 */
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/* GNU Library General Public License for more details. */
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#ifndef _DESCR_H
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#define _DESCR_H 1
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#define __need_res_state
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#include <resolv.h>
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#include <sched.h>
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#include <setjmp.h>
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#include <signal.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <hp-timing.h>
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#include <tls.h>
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/* Fast thread-specific data internal to libc. */
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enum __libc_tsd_key_t { _LIBC_TSD_KEY_MALLOC = 0,
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_LIBC_TSD_KEY_DL_ERROR,
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_LIBC_TSD_KEY_RPC_VARS,
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_LIBC_TSD_KEY_LOCALE,
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_LIBC_TSD_KEY_CTYPE_B,
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_LIBC_TSD_KEY_CTYPE_TOLOWER,
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_LIBC_TSD_KEY_CTYPE_TOUPPER,
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_LIBC_TSD_KEY_N };
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/* The type of thread descriptors */
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typedef struct _pthread_descr_struct *pthread_descr;
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/* Some more includes. */
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#include <pt-machine.h>
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#include <linuxthreads_db/thread_dbP.h>
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/* Arguments passed to thread creation routine */
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struct pthread_start_args {
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void *(*start_routine)(void *); /* function to run */
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void *arg; /* its argument */
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sigset_t mask; /* initial signal mask for thread */
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int schedpolicy; /* initial scheduling policy (if any) */
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struct sched_param schedparam; /* initial scheduling parameters (if any) */
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};
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/* Callback interface for removing the thread from waiting on an
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object if it is cancelled while waiting or about to wait.
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This hold a pointer to the object, and a pointer to a function
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which ``extricates'' the thread from its enqueued state.
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The function takes two arguments: pointer to the wait object,
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and a pointer to the thread. It returns 1 if an extrication
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actually occured, and hence the thread must also be signalled.
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It returns 0 if the thread had already been extricated. */
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typedef struct _pthread_extricate_struct {
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void *pu_object;
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int (*pu_extricate_func)(void *, pthread_descr);
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} pthread_extricate_if;
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/* Atomic counter made possible by compare_and_swap */
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struct pthread_atomic {
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long p_count;
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int p_spinlock;
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};
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/* Context info for read write locks. The pthread_rwlock_info structure
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is information about a lock that has been read-locked by the thread
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in whose list this structure appears. The pthread_rwlock_context
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is embedded in the thread context and contains a pointer to the
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head of the list of lock info structures, as well as a count of
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read locks that are untracked, because no info structure could be
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allocated for them. */
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struct _pthread_rwlock_t;
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typedef struct _pthread_rwlock_info {
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struct _pthread_rwlock_info *pr_next;
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struct _pthread_rwlock_t *pr_lock;
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int pr_lock_count;
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} pthread_readlock_info;
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/* We keep thread specific data in a special data structure, a two-level
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array. The top-level array contains pointers to dynamically allocated
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arrays of a certain number of data pointers. So we can implement a
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sparse array. Each dynamic second-level array has
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PTHREAD_KEY_2NDLEVEL_SIZE
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entries. This value shouldn't be too large. */
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#define PTHREAD_KEY_2NDLEVEL_SIZE 32
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/* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
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keys in each subarray. */
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#define PTHREAD_KEY_1STLEVEL_SIZE \
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((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
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/ PTHREAD_KEY_2NDLEVEL_SIZE)
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union dtv;
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struct _pthread_descr_struct
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{
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#if !defined USE_TLS || !TLS_DTV_AT_TP
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/* This overlaps tcbhead_t (see tls.h), as used for TLS without threads. */
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union
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{
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struct
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{
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void *tcb; /* Pointer to the TCB. This is not always
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the address of this thread descriptor. */
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union dtv *dtvp;
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pthread_descr self; /* Pointer to this structure */
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int multiple_threads;
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# ifdef NEED_DL_SYSINFO
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uintptr_t sysinfo;
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# endif
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} data;
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void *__padding[16];
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} p_header;
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# define p_multiple_threads p_header.data.multiple_threads
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#elif TLS_MULTIPLE_THREADS_IN_TCB
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int p_multiple_threads;
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#endif
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pthread_descr p_nextlive, p_prevlive;
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/* Double chaining of active threads */
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pthread_descr p_nextwaiting; /* Next element in the queue holding the thr */
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pthread_descr p_nextlock; /* can be on a queue and waiting on a lock */
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pthread_t p_tid; /* Thread identifier */
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int p_pid; /* PID of Unix process */
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int p_priority; /* Thread priority (== 0 if not realtime) */
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struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
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int p_signal; /* last signal received */
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sigjmp_buf * p_signal_jmp; /* where to siglongjmp on a signal or NULL */
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sigjmp_buf * p_cancel_jmp; /* where to siglongjmp on a cancel or NULL */
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char p_terminated; /* true if terminated e.g. by pthread_exit */
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char p_detached; /* true if detached */
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char p_exited; /* true if the assoc. process terminated */
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void * p_retval; /* placeholder for return value */
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int p_retcode; /* placeholder for return code */
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pthread_descr p_joining; /* thread joining on that thread or NULL */
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struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
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char p_cancelstate; /* cancellation state */
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char p_canceltype; /* cancellation type (deferred/async) */
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char p_canceled; /* cancellation request pending */
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char * p_in_sighandler; /* stack address of sighandler, or NULL */
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char p_sigwaiting; /* true if a sigwait() is in progress */
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struct pthread_start_args p_start_args; /* arguments for thread creation */
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void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
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#if !(USE_TLS && HAVE___THREAD)
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void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
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int * p_errnop; /* pointer to used errno variable */
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int p_errno; /* error returned by last system call */
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int * p_h_errnop; /* pointer to used h_errno variable */
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int p_h_errno; /* error returned by last netdb function */
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struct __res_state *p_resp; /* Pointer to resolver state */
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#endif
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struct __res_state p_res; /* per-thread resolver state */
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int p_userstack; /* nonzero if the user provided the stack */
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void *p_guardaddr; /* address of guard area or NULL */
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size_t p_guardsize; /* size of guard area */
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int p_nr; /* Index of descriptor in __pthread_handles */
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int p_report_events; /* Nonzero if events must be reported. */
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td_eventbuf_t p_eventbuf; /* Data for event. */
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struct pthread_atomic p_resume_count; /* number of times restart() was
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called on thread */
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char p_woken_by_cancel; /* cancellation performed wakeup */
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char p_condvar_avail; /* flag if conditional variable became avail */
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char p_sem_avail; /* flag if semaphore became available */
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pthread_extricate_if *p_extricate; /* See above */
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pthread_readlock_info *p_readlock_list; /* List of readlock info structs */
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pthread_readlock_info *p_readlock_free; /* Free list of structs */
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int p_untracked_readlock_count; /* Readlocks not tracked by list */
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int p_inheritsched; /* copied from the thread attribute */
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#if HP_TIMING_AVAIL
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hp_timing_t p_cpuclock_offset; /* Initial CPU clock for thread. */
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#endif
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#ifdef USE_TLS
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char *p_stackaddr; /* Stack address. */
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#endif
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size_t p_alloca_cutoff; /* Maximum size which should be allocated
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using alloca() instead of malloc(). */
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/* New elements must be added at the end. */
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} __attribute__ ((aligned(32))); /* We need to align the structure so that
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doubles are aligned properly. This is 8
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bytes on MIPS and 16 bytes on MIPS64.
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32 bytes might give better cache
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utilization. */
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/* Limit between the stack of the initial thread (above) and the
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stacks of other threads (below). Aligned on a STACK_SIZE boundary.
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Initially 0, meaning that the current thread is (by definition)
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the initial thread. */
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extern char *__pthread_initial_thread_bos;
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/* Descriptor of the initial thread */
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extern struct _pthread_descr_struct __pthread_initial_thread;
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/* Limits of the thread manager stack. */
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extern char *__pthread_manager_thread_bos;
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extern char *__pthread_manager_thread_tos;
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/* Descriptor of the manager thread */
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extern struct _pthread_descr_struct __pthread_manager_thread;
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/* Indicate whether at least one thread has a user-defined stack (if 1),
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or all threads have stacks supplied by LinuxThreads (if 0). */
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extern int __pthread_nonstandard_stacks;
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/* The max size of the thread stack segments. If the default
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THREAD_SELF implementation is used, this must be a power of two and
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a multiple of PAGE_SIZE. */
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#ifndef STACK_SIZE
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#define STACK_SIZE (2 * 1024 * 1024)
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#endif
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/* Get some notion of the current stack. Need not be exactly the top
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of the stack, just something somewhere in the current frame. */
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#ifndef CURRENT_STACK_FRAME
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#define CURRENT_STACK_FRAME ({ char __csf; &__csf; })
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#endif
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/* Recover thread descriptor for the current thread */
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extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
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static inline pthread_descr thread_self (void) __attribute__ ((const));
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static inline pthread_descr thread_self (void)
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{
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#ifdef THREAD_SELF
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return THREAD_SELF;
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#else
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char *sp = CURRENT_STACK_FRAME;
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if (sp >= __pthread_initial_thread_bos)
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return &__pthread_initial_thread;
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else if (sp >= __pthread_manager_thread_bos
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&& sp < __pthread_manager_thread_tos)
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return &__pthread_manager_thread;
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else if (__pthread_nonstandard_stacks)
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return __pthread_find_self();
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else
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#ifdef _STACK_GROWS_DOWN
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return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
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#else
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return (pthread_descr)((unsigned long)sp &~ (STACK_SIZE-1));
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#endif
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#endif
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}
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#endif /* descr.h */
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