/**
* util/locks.c - unbound locking primitives
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/**
* \file
* Implementation of locking and threading support.
* A place for locking debug code since most locking functions are macros.
*/

#include "config.h"
#include "util/locks.h"
#include <signal.h>
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif

/** block all signals, masks them away. */
void
ub_thread_blocksigs(void)
{
#if defined(HAVE_PTHREAD) || defined(HAVE_SOLARIS_THREADS) || defined(HAVE_SIGPROCMASK)
#  if defined(HAVE_PTHREAD) || defined(HAVE_SOLARIS_THREADS)
       int err;
#  endif
       sigset_t sigset;
       sigfillset(&sigset);
#ifdef HAVE_PTHREAD
       if((err=pthread_sigmask(SIG_SETMASK, &sigset, NULL)))
               fatal_exit("pthread_sigmask: %s", strerror(err));
#else
#  ifdef HAVE_SOLARIS_THREADS
       if((err=thr_sigsetmask(SIG_SETMASK, &sigset, NULL)))
               fatal_exit("thr_sigsetmask: %s", strerror(err));
#  else
       /* have nothing, do single process signal mask */
       if(sigprocmask(SIG_SETMASK, &sigset, NULL))
               fatal_exit("sigprocmask: %s", strerror(errno));
#  endif /* HAVE_SOLARIS_THREADS */
#endif /* HAVE_PTHREAD */
#endif /* have signal stuff */
}

/** unblock one signal, so we can catch it */
void ub_thread_sig_unblock(int sig)
{
#if defined(HAVE_PTHREAD) || defined(HAVE_SOLARIS_THREADS) || defined(HAVE_SIGPROCMASK)
#  if defined(HAVE_PTHREAD) || defined(HAVE_SOLARIS_THREADS)
       int err;
#  endif
       sigset_t sigset;
       sigemptyset(&sigset);
       sigaddset(&sigset, sig);
#ifdef HAVE_PTHREAD
       if((err=pthread_sigmask(SIG_UNBLOCK, &sigset, NULL)))
               fatal_exit("pthread_sigmask: %s", strerror(err));
#else
#  ifdef HAVE_SOLARIS_THREADS
       if((err=thr_sigsetmask(SIG_UNBLOCK, &sigset, NULL)))
               fatal_exit("thr_sigsetmask: %s", strerror(err));
#  else
       /* have nothing, do single thread case */
       if(sigprocmask(SIG_UNBLOCK, &sigset, NULL))
               fatal_exit("sigprocmask: %s", strerror(errno));
#  endif /* HAVE_SOLARIS_THREADS */
#endif /* HAVE_PTHREAD */
#else
       (void)sig;
#endif /* have signal stuff */
}

#if !defined(HAVE_PTHREAD) && !defined(HAVE_SOLARIS_THREADS) && !defined(HAVE_WINDOWS_THREADS)
/**
* No threading available: fork a new process.
* This means no shared data structure, and no locking.
* Only the main thread ever returns. Exits on errors.
* @param thr: the location where to store the thread-id.
* @param func: function body of the thread. Return value of func is lost.
* @param arg: user argument to func.
*/
void
ub_thr_fork_create(ub_thread_type* thr, void* (*func)(void*), void* arg)
{
       pid_t pid = fork();
       switch(pid) {
       default:        /* main */
                       *thr = (ub_thread_type)pid;
                       return;
       case 0:         /* child */
                       *thr = (ub_thread_type)getpid();
                       (void)(*func)(arg);
                       exit(0);
       case -1:        /* error */
                       fatal_exit("could not fork: %s", strerror(errno));
       }
}

/**
* There is no threading. Wait for a process to terminate.
* Note that ub_thread_type is defined as pid_t.
* @param thread: the process id to wait for.
*/
void ub_thr_fork_wait(ub_thread_type thread)
{
       int status = 0;
       if(waitpid((pid_t)thread, &status, 0) == -1)
               log_err("waitpid(%d): %s", (int)thread, strerror(errno));
       if(status != 0)
               log_warn("process %d abnormal exit with status %d",
                       (int)thread, status);
}
#endif /* !defined(HAVE_PTHREAD) && !defined(HAVE_SOLARIS_THREADS) && !defined(HAVE_WINDOWS_THREADS) */

#ifdef HAVE_SOLARIS_THREADS
void* ub_thread_key_get(ub_thread_key_type key)
{
       void* ret=NULL;
       LOCKRET(thr_getspecific(key, &ret));
       return ret;
}
#endif

#ifdef HAVE_WINDOWS_THREADS
/** log a windows GetLastError message */
static void log_win_err(const char* str, DWORD err)
{
       LPTSTR buf;
       if(FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
               FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_ALLOCATE_BUFFER,
               NULL, err, 0, (LPTSTR)&buf, 0, NULL) == 0) {
               /* could not format error message */
               log_err("%s, GetLastError=%d", str, (int)err);
               return;
       }
       log_err("%s, (err=%d): %s", str, (int)err, buf);
       LocalFree(buf);
}

void lock_basic_init(lock_basic_type* lock)
{
       /* implement own lock, because windows HANDLE as Mutex usage
        * uses too many handles and would bog down the whole system. */
       (void)InterlockedExchange(lock, 0);
}

void lock_basic_destroy(lock_basic_type* lock)
{
       (void)InterlockedExchange(lock, 0);
}

void lock_basic_lock(lock_basic_type* lock)
{
       LONG wait = 1; /* wait 1 msec at first */

       while(InterlockedExchange(lock, 1)) {
               /* if the old value was 1 then if was already locked */
               Sleep(wait); /* wait with sleep */
               wait *= 2;   /* exponential backoff for waiting */
       }
       /* the old value was 0, but we inserted 1, we locked it! */
}

void lock_basic_unlock(lock_basic_type* lock)
{
       /* unlock it by inserting the value of 0. xchg for cache coherency. */
       (void)InterlockedExchange(lock, 0);
}

void ub_thread_key_create(ub_thread_key_type* key, void* f)
{
       *key = TlsAlloc();
       if(*key == TLS_OUT_OF_INDEXES) {
               *key = 0;
               log_win_err("TlsAlloc Failed(OUT_OF_INDEXES)", GetLastError());
       }
       else ub_thread_key_set(*key, f);
}

void ub_thread_key_set(ub_thread_key_type key, void* v)
{
       if(!TlsSetValue(key, v)) {
               log_win_err("TlsSetValue failed", GetLastError());
       }
}

void* ub_thread_key_get(ub_thread_key_type key)
{
       void* ret = (void*)TlsGetValue(key);
       if(ret == NULL && GetLastError() != ERROR_SUCCESS) {
               log_win_err("TlsGetValue failed", GetLastError());
       }
       return ret;
}

void ub_thread_create(ub_thread_type* thr, void* (*func)(void*), void* arg)
{
#ifndef HAVE__BEGINTHREADEX
       *thr = CreateThread(NULL, /* default security (no inherit handle) */
               0, /* default stack size */
               (LPTHREAD_START_ROUTINE)func, arg,
               0, /* default flags, run immediately */
               NULL); /* do not store thread identifier anywhere */
#else
       /* the beginthreadex routine setups for the C lib; aligns stack */
       *thr=(ub_thread_type)_beginthreadex(NULL, 0, (void*)func, arg, 0, NULL);
#endif
       if(*thr == NULL) {
               log_win_err("CreateThread failed", GetLastError());
               fatal_exit("thread create failed");
       }
}

ub_thread_type ub_thread_self(void)
{
       return GetCurrentThread();
}

void ub_thread_join(ub_thread_type thr)
{
       DWORD ret = WaitForSingleObject(thr, INFINITE);
       if(ret == WAIT_FAILED) {
               log_win_err("WaitForSingleObject(Thread):WAIT_FAILED",
                       GetLastError());
       } else if(ret == WAIT_TIMEOUT) {
               log_win_err("WaitForSingleObject(Thread):WAIT_TIMEOUT",
                       GetLastError());
       }
       /* and close the handle to the thread */
       if(!CloseHandle(thr)) {
               log_win_err("CloseHandle(Thread) failed", GetLastError());
       }
}
#endif /* HAVE_WINDOWS_THREADS */

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