server/common/utils.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 *
 * Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 *
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 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 General Public License for more details.
 *
 * You should have received a copy of the Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

/*
 * General convenience functions for deliantra.
 */

#include <cstdlib>
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <time.h>
#include <signal.h>

#include <global.h>
#include <material.h>
#include <object.h>

#include <sys/time.h>
#include <sys/resource.h>

#include <glib.h>

refcnt_base::refcnt_t refcnt_dummy;
ssize_t slice_alloc;

/******************************************************************************/

/* Checks a player-provided string which will become the msg property of
 * an object for dangerous input.
 */
bool
msg_is_safe (const char *msg)
{
  bool safe = true;

  /* Trying to cheat by getting data into the object */
  if (!strncmp (msg, "endmsg", sizeof ("endmsg") - 1)
      || strstr (msg, "\nendmsg"))
    safe = false;

  /* Trying to make the object talk, and potentially access arbitrary code */
  if (object::msg_has_dialogue (msg))
    safe = false;

  return safe;
}

/////////////////////////////////////////////////////////////////////////////

void
fork_abort (const char *msg)
{
  if (!fork ())
    {
      signal (SIGINT , SIG_IGN);
      signal (SIGTERM, SIG_IGN);
      signal (SIGABRT, SIG_IGN);

      signal (SIGSEGV, SIG_DFL);
      signal (SIGFPE , SIG_DFL);
#ifdef SIGBUS
      signal (SIGBUS , SIG_DFL);
#endif
      signal (SIGILL , SIG_DFL);
      signal (SIGTRAP, SIG_DFL);

      // try to put corefiles into a subdirectory, if existing, to allow
      // an administrator to reduce the I/O load.
      chdir ("cores");

      // try to detach us from as many external dependencies as possible
      // as coredumping can take time by closing all fd's.
      {
        struct rlimit lim;

        if (getrlimit (RLIMIT_NOFILE, &lim))
          lim.rlim_cur = 1024;

        for (int i = 0; i < lim.rlim_cur; ++i)
          close (i);
      }

      {
        sigset_t empty;
        sigemptyset (&empty);
        sigprocmask (SIG_SETMASK, &empty, 0);
      }

      // try to coredump with SIGTRAP
      kill (getpid (), SIGTRAP);
      abort ();
    }

  LOG (llevError, "fork abort: %s\n", msg);
}

void *
salloc_ (int n)
{
  void *ptr = g_slice_alloc (n);

  if (!ptr)
    throw std::bad_alloc ();

  slice_alloc += n;
  return ptr;
}

void *
salloc_ (int n, void *src)
{
  void *ptr = salloc_ (n);

  if (src)
    memcpy (ptr, src, n);
  else
    memset (ptr, 0, n);

  return ptr;
}

/******************************************************************************/

#if DEBUG_SALLOC

#define MAGIC 0xa1b2c35543deadLL

void *
g_slice_alloc (unsigned long size)
{
  unsigned long *p = (unsigned long *) (g_slice_alloc)(size + sizeof (unsigned long));
  *p++ = size ^ MAGIC;
  //fprintf (stderr, "g_slice_alloc %ld %p\n", size, p);//D
  return (void *)p;
}

void *
g_slice_alloc0 (unsigned long size)
{
  return memset (g_slice_alloc (size), 0, size);
}

void
g_slice_free1 (unsigned long size, void *ptr)
{
  //fprintf (stderr, "g_slice_free %ld %p\n", size, ptr);//D
  if (expect_true (ptr))
    {
      unsigned long *p = (unsigned long *)ptr;
      unsigned long s = *--p ^ MAGIC;

      if (size != (unsigned long)(*p ^ MAGIC))
        {
          LOG (logBacktrace | llevError, "slice free size (%lx) doesn't match alloc size (%lx)\n", size, s);
          abort ();
        }

      *p = MAGIC;

      (g_slice_free1)(s + sizeof (unsigned long), p);
    }
}

#endif

/******************************************************************************/

refcnt_buf::refcnt_buf (size_t size)
{
  static uint32_t empty_buf [2] = { 0, 1 }; // 2 == never deallocated
  data = (char *)empty_buf + overhead;
  assert (overhead == sizeof (empty_buf));
  inc ();
}

refcnt_buf::refcnt_buf (void *data, size_t size)
{
  _alloc (size);
  memcpy (this->data, data, size);
}

refcnt_buf::~refcnt_buf ()
{
  dec ();
}

void
refcnt_buf::_dealloc ()
{
  sfree<char> (data - overhead, size () + overhead);
}

refcnt_buf &
refcnt_buf::operator =(const refcnt_buf &src)
{
  dec ();
  data = src.data;
  inc ();
  return *this;
}

/******************************************************************************/

int
assign (char *dst, const char *src, int maxsize)
{
  if (!src)
    src = "";

  int len = strlen (src);

  if (len >= maxsize)
    {
      if (maxsize <= 4)
        {
          memset (dst, '.', maxsize - 2);
          dst [maxsize - 1] = 0;
        }
      else
        {
          memcpy (dst, src, maxsize - 4);
          memcpy (dst + maxsize - 4, "...", 4);
        }

      len = maxsize;
    }
  else
    memcpy (dst, src, ++len);

  return len;
}

char *
vformat (const char *format, va_list ap)
{
  static dynbuf_text bufs[8];
  static int bufidx;

  dynbuf_text &buf = bufs [++bufidx & 7];

  buf.clear ();
  buf.vprintf (format, ap);
  return buf;
}

char *
format (const char *format, ...)
{
  va_list ap;
  va_start (ap, format);
  char *buf = vformat (format, ap);
  va_end (ap);

  return buf;
}

tstamp
now ()
{
  struct timeval tv;

  gettimeofday (&tv, 0);
  return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
}

int
similar_direction (int a, int b)
{
  if (!a || !b)
    return 0;

  int diff = (b - a) & 7;
  return diff <= 1 || diff >= 7;
}

/* crc32 0xdebb20e3 table and supplementary functions.  */
extern const uint32_t crc_32_tab[256] =
{
    0x00000000UL, 0x77073096UL, 0xee0e612cUL, 0x990951baUL, 0x076dc419UL,
    0x706af48fUL, 0xe963a535UL, 0x9e6495a3UL, 0x0edb8832UL, 0x79dcb8a4UL,
    0xe0d5e91eUL, 0x97d2d988UL, 0x09b64c2bUL, 0x7eb17cbdUL, 0xe7b82d07UL,
    0x90bf1d91UL, 0x1db71064UL, 0x6ab020f2UL, 0xf3b97148UL, 0x84be41deUL,
    0x1adad47dUL, 0x6ddde4ebUL, 0xf4d4b551UL, 0x83d385c7UL, 0x136c9856UL,
    0x646ba8c0UL, 0xfd62f97aUL, 0x8a65c9ecUL, 0x14015c4fUL, 0x63066cd9UL,
    0xfa0f3d63UL, 0x8d080df5UL, 0x3b6e20c8UL, 0x4c69105eUL, 0xd56041e4UL,
    0xa2677172UL, 0x3c03e4d1UL, 0x4b04d447UL, 0xd20d85fdUL, 0xa50ab56bUL,
    0x35b5a8faUL, 0x42b2986cUL, 0xdbbbc9d6UL, 0xacbcf940UL, 0x32d86ce3UL,
    0x45df5c75UL, 0xdcd60dcfUL, 0xabd13d59UL, 0x26d930acUL, 0x51de003aUL,
    0xc8d75180UL, 0xbfd06116UL, 0x21b4f4b5UL, 0x56b3c423UL, 0xcfba9599UL,
    0xb8bda50fUL, 0x2802b89eUL, 0x5f058808UL, 0xc60cd9b2UL, 0xb10be924UL,
    0x2f6f7c87UL, 0x58684c11UL, 0xc1611dabUL, 0xb6662d3dUL, 0x76dc4190UL,
    0x01db7106UL, 0x98d220bcUL, 0xefd5102aUL, 0x71b18589UL, 0x06b6b51fUL,
    0x9fbfe4a5UL, 0xe8b8d433UL, 0x7807c9a2UL, 0x0f00f934UL, 0x9609a88eUL,
    0xe10e9818UL, 0x7f6a0dbbUL, 0x086d3d2dUL, 0x91646c97UL, 0xe6635c01UL,
    0x6b6b51f4UL, 0x1c6c6162UL, 0x856530d8UL, 0xf262004eUL, 0x6c0695edUL,
    0x1b01a57bUL, 0x8208f4c1UL, 0xf50fc457UL, 0x65b0d9c6UL, 0x12b7e950UL,
    0x8bbeb8eaUL, 0xfcb9887cUL, 0x62dd1ddfUL, 0x15da2d49UL, 0x8cd37cf3UL,
    0xfbd44c65UL, 0x4db26158UL, 0x3ab551ceUL, 0xa3bc0074UL, 0xd4bb30e2UL,
    0x4adfa541UL, 0x3dd895d7UL, 0xa4d1c46dUL, 0xd3d6f4fbUL, 0x4369e96aUL,
    0x346ed9fcUL, 0xad678846UL, 0xda60b8d0UL, 0x44042d73UL, 0x33031de5UL,
    0xaa0a4c5fUL, 0xdd0d7cc9UL, 0x5005713cUL, 0x270241aaUL, 0xbe0b1010UL,
    0xc90c2086UL, 0x5768b525UL, 0x206f85b3UL, 0xb966d409UL, 0xce61e49fUL,
    0x5edef90eUL, 0x29d9c998UL, 0xb0d09822UL, 0xc7d7a8b4UL, 0x59b33d17UL,
    0x2eb40d81UL, 0xb7bd5c3bUL, 0xc0ba6cadUL, 0xedb88320UL, 0x9abfb3b6UL,
    0x03b6e20cUL, 0x74b1d29aUL, 0xead54739UL, 0x9dd277afUL, 0x04db2615UL,
    0x73dc1683UL, 0xe3630b12UL, 0x94643b84UL, 0x0d6d6a3eUL, 0x7a6a5aa8UL,
    0xe40ecf0bUL, 0x9309ff9dUL, 0x0a00ae27UL, 0x7d079eb1UL, 0xf00f9344UL,
    0x8708a3d2UL, 0x1e01f268UL, 0x6906c2feUL, 0xf762575dUL, 0x806567cbUL,
    0x196c3671UL, 0x6e6b06e7UL, 0xfed41b76UL, 0x89d32be0UL, 0x10da7a5aUL,
    0x67dd4accUL, 0xf9b9df6fUL, 0x8ebeeff9UL, 0x17b7be43UL, 0x60b08ed5UL,
    0xd6d6a3e8UL, 0xa1d1937eUL, 0x38d8c2c4UL, 0x4fdff252UL, 0xd1bb67f1UL,
    0xa6bc5767UL, 0x3fb506ddUL, 0x48b2364bUL, 0xd80d2bdaUL, 0xaf0a1b4cUL,
    0x36034af6UL, 0x41047a60UL, 0xdf60efc3UL, 0xa867df55UL, 0x316e8eefUL,
    0x4669be79UL, 0xcb61b38cUL, 0xbc66831aUL, 0x256fd2a0UL, 0x5268e236UL,
    0xcc0c7795UL, 0xbb0b4703UL, 0x220216b9UL, 0x5505262fUL, 0xc5ba3bbeUL,
    0xb2bd0b28UL, 0x2bb45a92UL, 0x5cb36a04UL, 0xc2d7ffa7UL, 0xb5d0cf31UL,
    0x2cd99e8bUL, 0x5bdeae1dUL, 0x9b64c2b0UL, 0xec63f226UL, 0x756aa39cUL,
    0x026d930aUL, 0x9c0906a9UL, 0xeb0e363fUL, 0x72076785UL, 0x05005713UL,
    0x95bf4a82UL, 0xe2b87a14UL, 0x7bb12baeUL, 0x0cb61b38UL, 0x92d28e9bUL,
    0xe5d5be0dUL, 0x7cdcefb7UL, 0x0bdbdf21UL, 0x86d3d2d4UL, 0xf1d4e242UL,
    0x68ddb3f8UL, 0x1fda836eUL, 0x81be16cdUL, 0xf6b9265bUL, 0x6fb077e1UL,
    0x18b74777UL, 0x88085ae6UL, 0xff0f6a70UL, 0x66063bcaUL, 0x11010b5cUL,
    0x8f659effUL, 0xf862ae69UL, 0x616bffd3UL, 0x166ccf45UL, 0xa00ae278UL,
    0xd70dd2eeUL, 0x4e048354UL, 0x3903b3c2UL, 0xa7672661UL, 0xd06016f7UL,
    0x4969474dUL, 0x3e6e77dbUL, 0xaed16a4aUL, 0xd9d65adcUL, 0x40df0b66UL,
    0x37d83bf0UL, 0xa9bcae53UL, 0xdebb9ec5UL, 0x47b2cf7fUL, 0x30b5ffe9UL,
    0xbdbdf21cUL, 0xcabac28aUL, 0x53b39330UL, 0x24b4a3a6UL, 0xbad03605UL,
    0xcdd70693UL, 0x54de5729UL, 0x23d967bfUL, 0xb3667a2eUL, 0xc4614ab8UL,
    0x5d681b02UL, 0x2a6f2b94UL, 0xb40bbe37UL, 0xc30c8ea1UL, 0x5a05df1bUL,
    0x2d02ef8dL
};

void
thread::start (void *(*start_routine)(void *), void *arg)
{
  pthread_attr_t attr;

  pthread_attr_init (&attr);
  pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
  pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN < sizeof (long) * 4096
                                    ? sizeof (long) * 4096 : PTHREAD_STACK_MIN);
#ifdef PTHREAD_SCOPE_PROCESS
  pthread_attr_setscope (&attr, PTHREAD_SCOPE_PROCESS);
#endif

  sigset_t fullsigset, oldsigset;
  sigfillset (&fullsigset);

  pthread_sigmask (SIG_SETMASK, &fullsigset, &oldsigset);

  if (pthread_create (&id, &attr, start_routine, arg))
    cleanup ("unable to create a new thread");

  pthread_sigmask (SIG_SETMASK, &oldsigset, 0);
}

Revision:	1.107
Committed:	Sat Nov 17 23:33:17 2018 UTC (5 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.106:	+0 -17 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	elmex	1.1	/*
2	root	1.68	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	root	1.101	*
4	root	1.104	* Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	root	1.101	*
6	root	1.89	* Deliantra is free software: you can redistribute it and/or modify it under
7			* the terms of the Affero GNU General Public License as published by the
8			* Free Software Foundation, either version 3 of the License, or (at your
9			* option) any later version.
10	root	1.101	*
11	root	1.60	* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15	root	1.101	*
16	root	1.89	* You should have received a copy of the Affero GNU General Public License
17			* and the GNU General Public License along with this program. If not, see
18			* <http://www.gnu.org/licenses/>.
19	root	1.101	*
20	root	1.68	* The authors can be reached via e-mail to <support@deliantra.net>
21	pippijn	1.39	*/
22	elmex	1.1
23			/*
24	root	1.92	* General convenience functions for deliantra.
25	elmex	1.1	*/
26
27	root	1.37	#include <cstdlib>
28			#include <sys/types.h>
29			#include <unistd.h>
30			#include <sys/time.h>
31			#include <time.h>
32			#include <signal.h>
33
34	elmex	1.1	#include <global.h>
35			#include <material.h>
36	sf-marcmagus	1.87	#include <object.h>
37	elmex	1.1
38	root	1.79	#include <sys/time.h>
39			#include <sys/resource.h>
40
41	root	1.4	#include <glib.h>
42
43	root	1.63	refcnt_base::refcnt_t refcnt_dummy;
44	root	1.74	ssize_t slice_alloc;
45	root	1.40
46	sf-marcmagus	1.87	/******************************************************************************/
47
48			/* Checks a player-provided string which will become the msg property of
49			* an object for dangerous input.
50			*/
51	root	1.105	bool
52	sf-marcmagus	1.87	msg_is_safe (const char *msg)
53			{
54			bool safe = true;
55
56			/* Trying to cheat by getting data into the object */
57	root	1.88	if (!strncmp (msg, "endmsg", sizeof ("endmsg") - 1)
58			\|\| strstr (msg, "\nendmsg"))
59	sf-marcmagus	1.87	safe = false;
60
61			/* Trying to make the object talk, and potentially access arbitrary code */
62			if (object::msg_has_dialogue (msg))
63			safe = false;
64
65			return safe;
66			}
67
68	root	1.14	/////////////////////////////////////////////////////////////////////////////
69
70	root	1.37	void
71			fork_abort (const char *msg)
72			{
73			if (!fork ())
74			{
75	root	1.80	signal (SIGINT , SIG_IGN);
76			signal (SIGTERM, SIG_IGN);
77			signal (SIGABRT, SIG_IGN);
78	root	1.79
79	root	1.81	signal (SIGSEGV, SIG_DFL);
80	root	1.103	signal (SIGFPE , SIG_DFL);
81			#ifdef SIGBUS
82	root	1.81	signal (SIGBUS , SIG_DFL);
83	root	1.103	#endif
84	root	1.81	signal (SIGILL , SIG_DFL);
85			signal (SIGTRAP, SIG_DFL);
86
87	root	1.52	// try to put corefiles into a subdirectory, if existing, to allow
88			// an administrator to reduce the I/O load.
89			chdir ("cores");
90	root	1.79
91			// try to detach us from as many external dependencies as possible
92			// as coredumping can take time by closing all fd's.
93			{
94			struct rlimit lim;
95
96			if (getrlimit (RLIMIT_NOFILE, &lim))
97			lim.rlim_cur = 1024;
98
99			for (int i = 0; i < lim.rlim_cur; ++i)
100			close (i);
101			}
102
103	root	1.81	{
104			sigset_t empty;
105			sigemptyset (&empty);
106			sigprocmask (SIG_SETMASK, &empty, 0);
107			}
108
109			// try to coredump with SIGTRAP
110			kill (getpid (), SIGTRAP);
111	root	1.37	abort ();
112			}
113
114	root	1.38	LOG (llevError, "fork abort: %s\n", msg);
115	root	1.37	}
116	root	1.38
117	root	1.99	void *
118	root	1.106	salloc_ (int n)
119	root	1.10	{
120	root	1.25	void *ptr = g_slice_alloc (n);
121	root	1.13
122	root	1.23	if (!ptr)
123	root	1.13	throw std::bad_alloc ();
124	root	1.4
125	root	1.74	slice_alloc += n;
126	root	1.23	return ptr;
127			}
128
129	root	1.99	void *
130	root	1.106	salloc_ (int n, void *src)
131	root	1.23	{
132	root	1.25	void *ptr = salloc_ (n);
133	root	1.23
134	root	1.24	if (src)
135	root	1.25	memcpy (ptr, src, n);
136	root	1.24	else
137	root	1.25	memset (ptr, 0, n);
138	root	1.23
139			return ptr;
140	root	1.3	}
141	root	1.11
142	root	1.69	/******************************************************************************/
143
144	root	1.72	#if DEBUG_SALLOC
145	root	1.69
146	root	1.70	#define MAGIC 0xa1b2c35543deadLL
147	root	1.69
148	root	1.99	void *
149			g_slice_alloc (unsigned long size)
150	root	1.69	{
151			unsigned long p = (unsigned long ) (g_slice_alloc)(size + sizeof (unsigned long));
152			*p++ = size ^ MAGIC;
153			//fprintf (stderr, "g_slice_alloc %ld %p\n", size, p);//D
154			return (void *)p;
155			}
156
157	root	1.99	void *
158			g_slice_alloc0 (unsigned long size)
159	root	1.69	{
160			return memset (g_slice_alloc (size), 0, size);
161			}
162
163	root	1.99	void
164			g_slice_free1 (unsigned long size, void *ptr)
165	root	1.69	{
166	root	1.74	//fprintf (stderr, "g_slice_free %ld %p\n", size, ptr);//D
167	root	1.69	if (expect_true (ptr))
168			{
169			unsigned long p = (unsigned long )ptr;
170			unsigned long s = *--p ^ MAGIC;
171
172	root	1.71	if (size != (unsigned long)(*p ^ MAGIC))
173	root	1.74	{
174			LOG (logBacktrace \| llevError, "slice free size (%lx) doesn't match alloc size (%lx)\n", size, s);
175			abort ();
176			}
177	root	1.69
178			*p = MAGIC;
179
180			(g_slice_free1)(s + sizeof (unsigned long), p);
181			}
182			}
183
184			#endif
185
186			/******************************************************************************/
187
188	root	1.99	refcnt_buf::refcnt_buf (size_t size)
189			{
190	root	1.102	static uint32_t empty_buf [2] = { 0, 1 }; // 2 == never deallocated
191			data = (char *)empty_buf + overhead;
192			assert (overhead == sizeof (empty_buf));
193			inc ();
194	root	1.99	}
195
196			refcnt_buf::refcnt_buf (void *data, size_t size)
197			{
198			_alloc (size);
199			memcpy (this->data, data, size);
200			}
201
202			refcnt_buf::~refcnt_buf ()
203			{
204			dec ();
205			}
206
207	root	1.102	void
208			refcnt_buf::_dealloc ()
209			{
210			sfree<char> (data - overhead, size () + overhead);
211			}
212
213	root	1.99	refcnt_buf &
214			refcnt_buf::operator =(const refcnt_buf &src)
215			{
216			dec ();
217			data = src.data;
218	root	1.102	inc ();
219	root	1.99	return *this;
220			}
221
222			/******************************************************************************/
223
224	root	1.86	int
225			assign (char dst, const char src, int maxsize)
226	root	1.11	{
227			if (!src)
228			src = "";
229
230			int len = strlen (src);
231
232	root	1.86	if (len >= maxsize)
233	root	1.11	{
234	root	1.86	if (maxsize <= 4)
235	root	1.11	{
236	root	1.86	memset (dst, '.', maxsize - 2);
237			dst [maxsize - 1] = 0;
238	root	1.11	}
239			else
240			{
241	root	1.86	memcpy (dst, src, maxsize - 4);
242			memcpy (dst + maxsize - 4, "...", 4);
243	root	1.11	}
244	root	1.86
245			len = maxsize;
246	root	1.11	}
247			else
248	root	1.86	memcpy (dst, src, ++len);
249
250			return len;
251	root	1.11	}
252
253	root	1.90	char *
254			vformat (const char *format, va_list ap)
255			{
256	root	1.96	static dynbuf_text bufs[8];
257			static int bufidx;
258
259			dynbuf_text &buf = bufs [++bufidx & 7];
260
261			buf.clear ();
262	root	1.90	buf.vprintf (format, ap);
263			return buf;
264			}
265
266			char *
267	root	1.51	format (const char *format, ...)
268			{
269	root	1.65	va_list ap;
270			va_start (ap, format);
271	root	1.90	char *buf = vformat (format, ap);
272	root	1.65	va_end (ap);
273
274			return buf;
275	root	1.51	}
276
277	root	1.99	tstamp
278			now ()
279	root	1.23	{
280			struct timeval tv;
281
282			gettimeofday (&tv, 0);
283			return tstamp (tv.tv_sec) + tstamp (tv.tv_usec) * tstamp (1e-6);
284			}
285	root	1.17
286	root	1.32	int
287			similar_direction (int a, int b)
288			{
289			if (!a \|\| !b)
290			return 0;
291
292			int diff = (b - a) & 7;
293			return diff <= 1 \|\| diff >= 7;
294			}
295
296	root	1.48	/* crc32 0xdebb20e3 table and supplementary functions. */
297			extern const uint32_t crc_32_tab[256] =
298			{
299			0x00000000UL, 0x77073096UL, 0xee0e612cUL, 0x990951baUL, 0x076dc419UL,
300			0x706af48fUL, 0xe963a535UL, 0x9e6495a3UL, 0x0edb8832UL, 0x79dcb8a4UL,
301			0xe0d5e91eUL, 0x97d2d988UL, 0x09b64c2bUL, 0x7eb17cbdUL, 0xe7b82d07UL,
302			0x90bf1d91UL, 0x1db71064UL, 0x6ab020f2UL, 0xf3b97148UL, 0x84be41deUL,
303			0x1adad47dUL, 0x6ddde4ebUL, 0xf4d4b551UL, 0x83d385c7UL, 0x136c9856UL,
304			0x646ba8c0UL, 0xfd62f97aUL, 0x8a65c9ecUL, 0x14015c4fUL, 0x63066cd9UL,
305			0xfa0f3d63UL, 0x8d080df5UL, 0x3b6e20c8UL, 0x4c69105eUL, 0xd56041e4UL,
306			0xa2677172UL, 0x3c03e4d1UL, 0x4b04d447UL, 0xd20d85fdUL, 0xa50ab56bUL,
307			0x35b5a8faUL, 0x42b2986cUL, 0xdbbbc9d6UL, 0xacbcf940UL, 0x32d86ce3UL,
308			0x45df5c75UL, 0xdcd60dcfUL, 0xabd13d59UL, 0x26d930acUL, 0x51de003aUL,
309			0xc8d75180UL, 0xbfd06116UL, 0x21b4f4b5UL, 0x56b3c423UL, 0xcfba9599UL,
310			0xb8bda50fUL, 0x2802b89eUL, 0x5f058808UL, 0xc60cd9b2UL, 0xb10be924UL,
311			0x2f6f7c87UL, 0x58684c11UL, 0xc1611dabUL, 0xb6662d3dUL, 0x76dc4190UL,
312			0x01db7106UL, 0x98d220bcUL, 0xefd5102aUL, 0x71b18589UL, 0x06b6b51fUL,
313			0x9fbfe4a5UL, 0xe8b8d433UL, 0x7807c9a2UL, 0x0f00f934UL, 0x9609a88eUL,
314			0xe10e9818UL, 0x7f6a0dbbUL, 0x086d3d2dUL, 0x91646c97UL, 0xe6635c01UL,
315			0x6b6b51f4UL, 0x1c6c6162UL, 0x856530d8UL, 0xf262004eUL, 0x6c0695edUL,
316			0x1b01a57bUL, 0x8208f4c1UL, 0xf50fc457UL, 0x65b0d9c6UL, 0x12b7e950UL,
317			0x8bbeb8eaUL, 0xfcb9887cUL, 0x62dd1ddfUL, 0x15da2d49UL, 0x8cd37cf3UL,
318			0xfbd44c65UL, 0x4db26158UL, 0x3ab551ceUL, 0xa3bc0074UL, 0xd4bb30e2UL,
319			0x4adfa541UL, 0x3dd895d7UL, 0xa4d1c46dUL, 0xd3d6f4fbUL, 0x4369e96aUL,
320			0x346ed9fcUL, 0xad678846UL, 0xda60b8d0UL, 0x44042d73UL, 0x33031de5UL,
321			0xaa0a4c5fUL, 0xdd0d7cc9UL, 0x5005713cUL, 0x270241aaUL, 0xbe0b1010UL,
322			0xc90c2086UL, 0x5768b525UL, 0x206f85b3UL, 0xb966d409UL, 0xce61e49fUL,
323			0x5edef90eUL, 0x29d9c998UL, 0xb0d09822UL, 0xc7d7a8b4UL, 0x59b33d17UL,
324			0x2eb40d81UL, 0xb7bd5c3bUL, 0xc0ba6cadUL, 0xedb88320UL, 0x9abfb3b6UL,
325			0x03b6e20cUL, 0x74b1d29aUL, 0xead54739UL, 0x9dd277afUL, 0x04db2615UL,
326			0x73dc1683UL, 0xe3630b12UL, 0x94643b84UL, 0x0d6d6a3eUL, 0x7a6a5aa8UL,
327			0xe40ecf0bUL, 0x9309ff9dUL, 0x0a00ae27UL, 0x7d079eb1UL, 0xf00f9344UL,
328			0x8708a3d2UL, 0x1e01f268UL, 0x6906c2feUL, 0xf762575dUL, 0x806567cbUL,
329			0x196c3671UL, 0x6e6b06e7UL, 0xfed41b76UL, 0x89d32be0UL, 0x10da7a5aUL,
330			0x67dd4accUL, 0xf9b9df6fUL, 0x8ebeeff9UL, 0x17b7be43UL, 0x60b08ed5UL,
331			0xd6d6a3e8UL, 0xa1d1937eUL, 0x38d8c2c4UL, 0x4fdff252UL, 0xd1bb67f1UL,
332			0xa6bc5767UL, 0x3fb506ddUL, 0x48b2364bUL, 0xd80d2bdaUL, 0xaf0a1b4cUL,
333			0x36034af6UL, 0x41047a60UL, 0xdf60efc3UL, 0xa867df55UL, 0x316e8eefUL,
334			0x4669be79UL, 0xcb61b38cUL, 0xbc66831aUL, 0x256fd2a0UL, 0x5268e236UL,
335			0xcc0c7795UL, 0xbb0b4703UL, 0x220216b9UL, 0x5505262fUL, 0xc5ba3bbeUL,
336			0xb2bd0b28UL, 0x2bb45a92UL, 0x5cb36a04UL, 0xc2d7ffa7UL, 0xb5d0cf31UL,
337			0x2cd99e8bUL, 0x5bdeae1dUL, 0x9b64c2b0UL, 0xec63f226UL, 0x756aa39cUL,
338			0x026d930aUL, 0x9c0906a9UL, 0xeb0e363fUL, 0x72076785UL, 0x05005713UL,
339			0x95bf4a82UL, 0xe2b87a14UL, 0x7bb12baeUL, 0x0cb61b38UL, 0x92d28e9bUL,
340			0xe5d5be0dUL, 0x7cdcefb7UL, 0x0bdbdf21UL, 0x86d3d2d4UL, 0xf1d4e242UL,
341			0x68ddb3f8UL, 0x1fda836eUL, 0x81be16cdUL, 0xf6b9265bUL, 0x6fb077e1UL,
342			0x18b74777UL, 0x88085ae6UL, 0xff0f6a70UL, 0x66063bcaUL, 0x11010b5cUL,
343			0x8f659effUL, 0xf862ae69UL, 0x616bffd3UL, 0x166ccf45UL, 0xa00ae278UL,
344			0xd70dd2eeUL, 0x4e048354UL, 0x3903b3c2UL, 0xa7672661UL, 0xd06016f7UL,
345			0x4969474dUL, 0x3e6e77dbUL, 0xaed16a4aUL, 0xd9d65adcUL, 0x40df0b66UL,
346			0x37d83bf0UL, 0xa9bcae53UL, 0xdebb9ec5UL, 0x47b2cf7fUL, 0x30b5ffe9UL,
347			0xbdbdf21cUL, 0xcabac28aUL, 0x53b39330UL, 0x24b4a3a6UL, 0xbad03605UL,
348			0xcdd70693UL, 0x54de5729UL, 0x23d967bfUL, 0xb3667a2eUL, 0xc4614ab8UL,
349			0x5d681b02UL, 0x2a6f2b94UL, 0xb40bbe37UL, 0xc30c8ea1UL, 0x5a05df1bUL,
350			0x2d02ef8dL
351			};
352
353	root	1.99	void
354			thread::start (void (start_routine)(void ), void arg)
355	root	1.73	{
356	root	1.75	pthread_attr_t attr;
357
358			pthread_attr_init (&attr);
359			pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
360			pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN < sizeof (long) * 4096
361			? sizeof (long) * 4096 : PTHREAD_STACK_MIN);
362			#ifdef PTHREAD_SCOPE_PROCESS
363			pthread_attr_setscope (&attr, PTHREAD_SCOPE_PROCESS);
364			#endif
365
366	root	1.73	sigset_t fullsigset, oldsigset;
367			sigfillset (&fullsigset);
368
369			pthread_sigmask (SIG_SETMASK, &fullsigset, &oldsigset);
370
371	root	1.75	if (pthread_create (&id, &attr, start_routine, arg))
372	root	1.73	cleanup ("unable to create a new thread");
373
374			pthread_sigmask (SIG_SETMASK, &oldsigset, 0);
375			}
376	root	1.75