pthread.c

Axis 221 camera embedded programing interface

/* Linuxthreads - a simple clone()-based implementation of Posix        */
/* threads for Linux.                                                   */
/* Copyright (C) 1996 Xavier Leroy ([e-mail])              */
/*                                                                      */
/* This program is free software; you can redistribute it and/or        */
/* modify it under the terms of the GNU Library General Public License  */
/* as published by the Free Software Foundation; either version 2       */
/* of the License, or (at your option) any later version.               */
/*                                                                      */
/* This program is distributed in the hope that it will be useful,      */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
/* GNU Library General Public License for more details.                 */

/* Thread creation, initialization, and basic low-level routines */

#define __FORCE_GLIBC
#include <features.h>
#define __USE_GNU
#include <errno.h>
#include <netdb.h>	/* for h_errno */
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/resource.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include "restart.h"
#include "debug.h"      /* added to linuxthreads -StS */


/* Mods for uClibc: Some includes */
#include <signal.h>
#include <sys/types.h>
#include <sys/syscall.h>

/* mods for uClibc: getpwd and getpagesize are the syscalls */
#define __getpid getpid
#define __getpagesize getpagesize
/* mods for uClibc: __libc_sigaction is not in any standard headers */
extern int __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact);


/* These variables are used by the setup code.  */
extern int _errno;
extern int _h_errno;


/* Descriptor of the initial thread */

struct _pthread_descr_struct __pthread_initial_thread = {
  &__pthread_initial_thread,  /* pthread_descr p_nextlive */
  &__pthread_initial_thread,  /* pthread_descr p_prevlive */
  NULL,                       /* pthread_descr p_nextwaiting */
  NULL,			      /* pthread_descr p_nextlock */
  PTHREAD_THREADS_MAX,        /* pthread_t p_tid */
  0,                          /* int p_pid */
  0,                          /* int p_priority */
  &__pthread_handles[0].h_lock, /* struct _pthread_fastlock * p_lock */
  0,                          /* int p_signal */
  NULL,                       /* sigjmp_buf * p_signal_buf */
  NULL,                       /* sigjmp_buf * p_cancel_buf */
  0,                          /* char p_terminated */
  0,                          /* char p_detached */
  0,                          /* char p_exited */
  NULL,                       /* void * p_retval */
  0,                          /* int p_retval */
  NULL,                       /* pthread_descr p_joining */
  NULL,                       /* struct _pthread_cleanup_buffer * p_cleanup */
  0,                          /* char p_cancelstate */
  0,                          /* char p_canceltype */
  0,                          /* char p_canceled */
  &_errno,                       /* int *p_errnop */
  0,                          /* int p_errno */
  &_h_errno,                       /* int *p_h_errnop */
  0,                          /* int p_h_errno */
  NULL,                       /* char * p_in_sighandler */
  0,                          /* char p_sigwaiting */
  PTHREAD_START_ARGS_INITIALIZER, /* struct pthread_start_args p_start_args */
  {NULL},                     /* void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE] */
  {NULL},                     /* void * p_libc_specific[_LIBC_TSD_KEY_N] */
  0,                          /* int p_userstack */
  NULL,                       /* void * p_guardaddr */
  0,                          /* size_t p_guardsize */
  &__pthread_initial_thread,  /* pthread_descr p_self */
  0,                          /* Always index 0 */
  0,                          /* int p_report_events */
  {{{0, }}, 0, NULL},         /* td_eventbuf_t p_eventbuf */
  __ATOMIC_INITIALIZER,         /* struct pthread_atomic p_resume_count */
  0,                          /* char p_woken_by_cancel */
  0,                          /* char p_condvar_avail */
  0,                          /* char p_sem_avail */
  NULL,                       /* struct pthread_extricate_if *p_extricate */
  NULL,	                      /* pthread_readlock_info *p_readlock_list; */
  NULL,                       /* pthread_readlock_info *p_readlock_free; */
  0                           /* int p_untracked_readlock_count; */
#ifdef __UCLIBC_HAS_XLOCALE__
  ,
  &__global_locale_data,      /* __locale_t locale; */
#endif /* __UCLIBC_HAS_XLOCALE__ */
};

/* Descriptor of the manager thread; none of this is used but the error
   variables, the p_pid and p_priority fields,
   and the address for identification.  */
#define manager_thread (&__pthread_manager_thread)
struct _pthread_descr_struct __pthread_manager_thread = {
  NULL,                       /* pthread_descr p_nextlive */
  NULL,                       /* pthread_descr p_prevlive */
  NULL,                       /* pthread_descr p_nextwaiting */
  NULL,			      /* pthread_descr p_nextlock */
  0,                          /* int p_tid */
  0,                          /* int p_pid */
  0,                          /* int p_priority */
  &__pthread_handles[1].h_lock, /* struct _pthread_fastlock * p_lock */
  0,                          /* int p_signal */
  NULL,                       /* sigjmp_buf * p_signal_buf */
  NULL,                       /* sigjmp_buf * p_cancel_buf */
  0,                          /* char p_terminated */
  0,                          /* char p_detached */
  0,                          /* char p_exited */
  NULL,                       /* void * p_retval */
  0,                          /* int p_retval */
  NULL,                       /* pthread_descr p_joining */
  NULL,                       /* struct _pthread_cleanup_buffer * p_cleanup */
  0,                          /* char p_cancelstate */
  0,                          /* char p_canceltype */
  0,                          /* char p_canceled */
  &__pthread_manager_thread.p_errno, /* int *p_errnop */
  0,                          /* int p_errno */
  NULL,                       /* int *p_h_errnop */
  0,                          /* int p_h_errno */
  NULL,                       /* char * p_in_sighandler */
  0,                          /* char p_sigwaiting */
  PTHREAD_START_ARGS_INITIALIZER, /* struct pthread_start_args p_start_args */
  {NULL},                     /* void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE] */
  {NULL},                     /* void * p_libc_specific[_LIBC_TSD_KEY_N] */
  0,                          /* int p_userstack */
  NULL,                       /* void * p_guardaddr */
  0,                          /* size_t p_guardsize */
  &__pthread_manager_thread,  /* pthread_descr p_self */
  1,                          /* Always index 1 */
  0,                          /* int p_report_events */
  {{{0, }}, 0, NULL},         /* td_eventbuf_t p_eventbuf */
  __ATOMIC_INITIALIZER,         /* struct pthread_atomic p_resume_count */
  0,                          /* char p_woken_by_cancel */
  0,                          /* char p_condvar_avail */
  0,                          /* char p_sem_avail */
  NULL,                       /* struct pthread_extricate_if *p_extricate */
  NULL,	                      /* pthread_readlock_info *p_readlock_list; */
  NULL,                       /* pthread_readlock_info *p_readlock_free; */
  0                           /* int p_untracked_readlock_count; */
#ifdef __UCLIBC_HAS_XLOCALE__
  ,
  &__global_locale_data,      /* __locale_t locale; */
#endif /* __UCLIBC_HAS_XLOCALE__ */
};

/* Pointer to the main thread (the father of the thread manager thread) */
/* Originally, this is the initial thread, but this changes after fork() */

pthread_descr __pthread_main_thread = &__pthread_initial_thread;

/* Limit between the stack of the initial thread (above) and the
   stacks of other threads (below). Aligned on a STACK_SIZE boundary. */

char *__pthread_initial_thread_bos = NULL;

/* For non-MMU systems also remember to stack top of the initial thread.
 * This is adapted when other stacks are malloc'ed since we don't know
 * the bounds a-priori. -StS */

#ifndef __ARCH_HAS_MMU__
char *__pthread_initial_thread_tos = NULL;
#endif /* __ARCH_HAS_MMU__ */

/* File descriptor for sending requests to the thread manager. */
/* Initially -1, meaning that the thread manager is not running. */

int __pthread_manager_request = -1;

/* Other end of the pipe for sending requests to the thread manager. */

int __pthread_manager_reader;

/* Limits of the thread manager stack */

char *__pthread_manager_thread_bos = NULL;
char *__pthread_manager_thread_tos = NULL;

/* For process-wide exit() */

int __pthread_exit_requested = 0;
int __pthread_exit_code = 0;

/* Communicate relevant LinuxThreads constants to gdb */

const int __pthread_threads_max = PTHREAD_THREADS_MAX;
const int __pthread_sizeof_handle = sizeof(struct pthread_handle_struct);
const int __pthread_offsetof_descr = offsetof(struct pthread_handle_struct, h_descr);
const int __pthread_offsetof_pid = offsetof(struct _pthread_descr_struct,
                                            p_pid);
const int __linuxthreads_pthread_sizeof_descr
  = sizeof(struct _pthread_descr_struct);

const int __linuxthreads_initial_report_events;

const char __linuxthreads_version[] = VERSION;

/* Forward declarations */
static void pthread_onexit_process(int retcode, void *arg);
static void pthread_handle_sigcancel(int sig);
static void pthread_handle_sigrestart(int sig);
static void pthread_handle_sigdebug(int sig);
int __pthread_timedsuspend_new(pthread_descr self, const struct timespec *abstime);

/* Signal numbers used for the communication.
   In these variables we keep track of the used variables.  If the
   platform does not support any real-time signals we will define the
   values to some unreasonable value which will signal failing of all
   the functions below.  */
#ifndef __NR_rt_sigaction
static int current_rtmin = -1;
static int current_rtmax = -1;
int __pthread_sig_restart = SIGUSR1;
int __pthread_sig_cancel = SIGUSR2;
int __pthread_sig_debug;
#else

#if __SIGRTMAX - __SIGRTMIN >= 3
static int current_rtmin = __SIGRTMIN + 3;
static int current_rtmax = __SIGRTMAX;
int __pthread_sig_restart = __SIGRTMIN;
int __pthread_sig_cancel = __SIGRTMIN + 1;
int __pthread_sig_debug = __SIGRTMIN + 2;
void (*__pthread_restart)(pthread_descr) = __pthread_restart_new;
void (*__pthread_suspend)(pthread_descr) = __pthread_wait_for_restart_signal;
int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *) = __pthread_timedsuspend_new;
#else
static int current_rtmin = __SIGRTMIN;
static int current_rtmax = __SIGRTMAX;
int __pthread_sig_restart = SIGUSR1;
int __pthread_sig_cancel = SIGUSR2;
int __pthread_sig_debug;
void (*__pthread_restart)(pthread_descr) = __pthread_restart_old;
void (*__pthread_suspend)(pthread_descr) = __pthread_suspend_old;
int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *) = __pthread_timedsuspend_old;

#endif

/* Return number of available real-time signal with highest priority.  */
int __libc_current_sigrtmin (void)
{
    return current_rtmin;
}

/* Return number of available real-time signal with lowest priority.  */
int __libc_current_sigrtmax (void)
{
    return current_rtmax;
}

/* Allocate real-time signal with highest/lowest available
   priority.  Please note that we don't use a lock since we assume
   this function to be called at program start.  */
int __libc_allocate_rtsig (int high)
{
    if (current_rtmin == -1 || current_rtmin > current_rtmax)
	/* We don't have anymore signal available.  */
	return -1;
    return high ? current_rtmin++ : current_rtmax--;
}
#endif

/* Initialize the pthread library.
   Initialization is split in two functions:
   - a constructor function that blocks the __pthread_sig_restart signal
     (must do this very early, since the program could capture the signal
      mask with e.g. sigsetjmp before creating the first thread);
   - a regular function called from pthread_create when needed. */

static void pthread_initialize(void) __attribute__((constructor));

 /* Do some minimal initialization which has to be done during the
    startup of the C library.  */
void __pthread_initialize_minimal(void)
{
    /* If we have special thread_self processing, initialize 
     * that for the main thread now.  */
#ifdef INIT_THREAD_SELF
    INIT_THREAD_SELF(&__pthread_initial_thread, 0);
#endif
}


static void pthread_initialize(void)
{
  struct sigaction sa;
  sigset_t mask;
  struct rlimit limit;
  int max_stack;

  /* If already done (e.g. by a constructor called earlier!), bail out */
  if (__pthread_initial_thread_bos != NULL) return;
#ifdef TEST_FOR_COMPARE_AND_SWAP
  /* Test if compare-and-swap is available */
  __pthread_has_cas = compare_and_swap_is_available();
#endif
  /* For the initial stack, reserve at least STACK_SIZE bytes of stack
     below the current stack address, and align that on a
     STACK_SIZE boundary. */
  __pthread_initial_thread_bos =
    (char *)(((long)CURRENT_STACK_FRAME - 2 * STACK_SIZE) & ~(STACK_SIZE - 1));
  /* Update the descriptor for the initial thread. */
  __pthread_initial_thread.p_pid = __getpid();
  /* If we have special thread_self processing, initialize that for the
     main thread now.  */
#ifdef INIT_THREAD_SELF
  INIT_THREAD_SELF(&__pthread_initial_thread, 0);
#endif
  /* The errno/h_errno variable of the main thread are the global ones.  */
  __pthread_initial_thread.p_errnop = &_errno;
  __pthread_initial_thread.p_h_errnop = &_h_errno;

#ifdef __UCLIBC_HAS_XLOCALE__
  /* The locale of the main thread is the current locale in use. */
  __pthread_initial_thread.locale = __curlocale_var;
#endif /* __UCLIBC_HAS_XLOCALE__ */

 {			   /* uClibc-specific stdio initialization for threads. */
	 FILE *fp;
	 
	 _stdio_user_locking = 0;	/* 2 if threading not initialized */
	 for (fp = _stdio_openlist; fp != NULL; fp = fp->__nextopen) {
		 if (fp->__user_locking != 1) {
			 fp->__user_locking = 0;
		 }
	 }
 }

  /* Play with the stack size limit to make sure that no stack ever grows
     beyond STACK_SIZE minus two pages (one page for the thread descriptor