EV/schmorp.h

#ifndef SCHMORP_PERL_H_
#define SCHMORP_PERL_H_

/* WARNING
 * This header file is a shared resource between many modules.
 */

#include <signal.h>
#include <errno.h>

#ifndef _WIN32
# include <poll.h>
#endif

/* useful stuff, used by schmorp mostly */

#include "patchlevel.h"

#define PERL_VERSION_ATLEAST(a,b,c)                             \
  (PERL_REVISION > (a)                                          \
   || (PERL_REVISION == (a)                                     \
       && (PERL_VERSION > (b)                                   \
           || (PERL_VERSION == (b) && PERL_SUBVERSION >= (c)))))

#ifndef PERL_MAGIC_ext
# define PERL_MAGIC_ext '~'
#endif

#if !PERL_VERSION_ATLEAST (5,6,0)
# ifndef PL_ppaddr
#  define PL_ppaddr ppaddr
# endif
# ifndef call_sv
#  define call_sv perl_call_sv
# endif
# ifndef get_sv
#  define get_sv perl_get_sv
# endif
# ifndef get_cv
#  define get_cv perl_get_cv
# endif
# ifndef IS_PADGV
#  define IS_PADGV(v) 0
# endif
# ifndef IS_PADCONST
#  define IS_PADCONST(v) 0
# endif
#endif

/* 5.11 */
#ifndef CxHASARGS
# define CxHASARGS(cx) (cx)->blk_sub.hasargs
#endif

/* 5.10.0 */
#ifndef SvREFCNT_inc_NN
# define SvREFCNT_inc_NN(sv) SvREFCNT_inc (sv)
#endif

/* 5.8.8 */
#ifndef GV_NOTQUAL
# define GV_NOTQUAL 0
#endif
#ifndef newSV
# define newSV(l) NEWSV(0,l)
#endif
#ifndef CvISXSUB_on
# define CvISXSUB_on(cv) (void)cv
#endif
#ifndef CvISXSUB
# define CvISXSUB(cv) (CvXSUB (cv) ? TRUE : FALSE)
#endif
#ifndef Newx
# define Newx(ptr,nitems,type) New (0,ptr,nitems,type)
#endif

/* 5.8.7 */
#ifndef SvRV_set
# define SvRV_set(s,v) SvRV(s) = (v)
#endif

static int
s_signum (SV *sig)
{
#ifndef SIG_SIZE
  /* kudos to Slaven Rezic for the idea */
  static char sig_size [] = { SIG_NUM };
# define SIG_SIZE (sizeof (sig_size) + 1)
#endif
  dTHX;
  int signum;

  SvGETMAGIC (sig);

  for (signum = 1; signum < SIG_SIZE; ++signum)
    if (strEQ (SvPV_nolen (sig), PL_sig_name [signum]))
      return signum;

  signum = SvIV (sig);

  if (signum > 0 && signum < SIG_SIZE)
    return signum;

  return -1;
}

static int
s_signum_croak (SV *sig)
{
  int signum = s_signum (sig);

  if (signum < 0)
    {
      dTHX;
      croak ("%s: invalid signal name or number", SvPV_nolen (sig));
    }

  return signum;
}

static int
s_fileno (SV *fh, int wr)
{
  dTHX;
  SvGETMAGIC (fh);

  if (SvROK (fh))
    {
      fh = SvRV (fh);
      SvGETMAGIC (fh);
    }

  if (SvTYPE (fh) == SVt_PVGV)
    return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));

  if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
    return SvIV (fh);

  return -1;
}

static int
s_fileno_croak (SV *fh, int wr)
{
  int fd = s_fileno (fh, wr);

  if (fd < 0)
    {
      dTHX;
      croak ("%s: illegal fh argument, either not an OS file or read/write mode mismatch", SvPV_nolen (fh));
    }

  return fd;
}

static SV *
s_get_cv (SV *cb_sv)
{
  dTHX;
  HV *st;
  GV *gvp;

  return (SV *)sv_2cv (cb_sv, &st, &gvp, 0);
}

static SV *
s_get_cv_croak (SV *cb_sv)
{
  SV *cv = s_get_cv (cb_sv);

  if (!cv)
    {
      dTHX;
      croak ("%s: callback must be a CODE reference or another callable object", SvPV_nolen (cb_sv));
    }

  return cv;
}

/*****************************************************************************/
/* gensub: simple closure generation utility */

#define S_GENSUB_ARG CvXSUBANY (cv).any_ptr

/* create a closure from XS, returns a code reference */
/* the arg can be accessed via GENSUB_ARG from the callback */
/* the callback must use dXSARGS/XSRETURN */
static SV *
s_gensub (pTHX_ void (*xsub)(pTHX_ CV *), void *arg)
{
  CV *cv = (CV *)newSV (0);

  sv_upgrade ((SV *)cv, SVt_PVCV);

  CvANON_on (cv);
  CvISXSUB_on (cv);
  CvXSUB (cv) = xsub;
  S_GENSUB_ARG = arg;

  return newRV_noinc ((SV *)cv);
}

/*****************************************************************************/
/* portable pipe/socketpair */

#ifdef USE_SOCKETS_AS_HANDLES
# define S_TO_HANDLE(x) ((HANDLE)win32_get_osfhandle (x))
#else
# define S_TO_HANDLE(x) ((HANDLE)x)
#endif

#ifdef _WIN32
/* taken almost verbatim from libev's ev_win32.c */
/* oh, the humanity! */
static int
s_pipe (int filedes [2])
{
  dTHX;

  struct sockaddr_in addr = { 0 };
  int addr_size = sizeof (addr);
  struct sockaddr_in adr2;
  int adr2_size = sizeof (adr2);
  SOCKET listener;
  SOCKET sock [2] = { -1, -1 };

  if ((listener = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) 
    return -1;

  addr.sin_family = AF_INET;
  addr.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
  addr.sin_port = 0;

  if (bind (listener, (struct sockaddr *)&addr, addr_size))
    goto fail;

  if (getsockname (listener, (struct sockaddr *)&addr, &addr_size))
    goto fail;

  if (listen (listener, 1))
    goto fail;

  if ((sock [0] = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) 
    goto fail;

  if (connect (sock [0], (struct sockaddr *)&addr, addr_size))
    goto fail;

  if ((sock [1] = accept (listener, 0, 0)) < 0)
    goto fail;

  /* windows vista returns fantasy port numbers for getpeername.
   * example for two interconnected tcp sockets:
   *
   * (Socket::unpack_sockaddr_in getsockname $sock0)[0] == 53364
   * (Socket::unpack_sockaddr_in getpeername $sock0)[0] == 53363
   * (Socket::unpack_sockaddr_in getsockname $sock1)[0] == 53363
   * (Socket::unpack_sockaddr_in getpeername $sock1)[0] == 53365
   *
   * wow! tridirectional sockets!
   *
   * this way of checking ports seems to work:
   */
  if (getpeername (sock [0], (struct sockaddr *)&addr, &addr_size))
    goto fail;

  if (getsockname (sock [1], (struct sockaddr *)&adr2, &adr2_size))
    goto fail;

  errno = WSAEINVAL;
  if (addr_size != adr2_size
      || addr.sin_addr.s_addr != adr2.sin_addr.s_addr /* just to be sure, I mean, it's windows */
      || addr.sin_port        != adr2.sin_port)
    goto fail;

  closesocket (listener);

#ifdef USE_SOCKETS_AS_HANDLES
  /* when select isn't winsocket, we also expect socket, connect, accept etc.
   * to work on fds */
  filedes [0] = sock [0];
  filedes [1] = sock [1];
#else
  filedes [0] = _open_osfhandle (sock [0], 0);
  filedes [1] = _open_osfhandle (sock [1], 0);
#endif

  return 0;

fail:
  closesocket (listener);

  if (sock [0] != INVALID_SOCKET) closesocket (sock [0]);
  if (sock [1] != INVALID_SOCKET) closesocket (sock [1]);

  return -1;
}

#define s_socketpair(domain,type,protocol,filedes) s_pipe (filedes)

static int
s_fd_blocking (int fd, int blocking)
{
  u_long nonblocking = !blocking;

  return ioctlsocket ((SOCKET)S_TO_HANDLE (fd), FIONBIO, &nonblocking);
}

#define s_fd_prepare(fd) s_fd_blocking (fd, 0)

#else

#define s_socketpair(domain,type,protocol,filedes) socketpair (domain, type, protocol, filedes)
#define s_pipe(filedes) pipe (filedes)

static int
s_fd_blocking (int fd, int blocking)
{
  return fcntl (fd, F_SETFL, blocking ? 0 : O_NONBLOCK);
}

static int
s_fd_prepare (int fd)
{
  return s_fd_blocking (fd, 0)
         || fcntl (fd, F_SETFD, FD_CLOEXEC);
}

#endif

#if __linux && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
# include <stdint.h>
# ifdef __cplusplus
extern "C" {
# endif
  int eventfd (unsigned int initval, int flags);
# ifdef __cplusplus
}
# endif
#else
# define eventfd(initval,flags) -1
#endif

typedef struct {
  int fd[2]; /* read, write fd, might be equal */
  int len; /* write length (1 pipe/socket, 8 eventfd) */
} s_epipe;

static int
s_epipe_new (s_epipe *epp)
{
  s_epipe ep;

  ep.fd [0] = ep.fd [1] = eventfd (0, 0);

  if (ep.fd [0] >= 0)
    {
      s_fd_prepare (ep.fd [0]);
      ep.len = 8;
    }
  else
    {
      if (s_pipe (ep.fd))
        return -1;

      if (s_fd_prepare (ep.fd [0])
          || s_fd_prepare (ep.fd [1]))
        {
           dTHX;

           close (ep.fd [0]);
           close (ep.fd [1]);
           return -1;
        }

      ep.len = 1;
    }

  *epp = ep;
  return 0;
}

static void
s_epipe_destroy (s_epipe *epp)
{
  dTHX;

  close (epp->fd [0]);

  if (epp->fd [1] != epp->fd [0])
    close (epp->fd [1]);

  epp->len = 0;
}

static void
s_epipe_signal (s_epipe *epp)
{
#ifdef _WIN32
  /* perl overrides send with a function that crashes in other threads.
   * unfortunately, it overrides it with an argument-less macro, so
   * there is no way to force usage of the real send function.
   * incompetent windows programmers - is this redundant?
   */
  DWORD dummy;
  WriteFile (S_TO_HANDLE (epp->fd [1]), (LPCVOID)&dummy, 1, &dummy, 0);
#else
  static uint64_t counter = 1;
  /* some modules accept fd's from outside, support eventfd here */
  if (write (epp->fd [1], &counter, epp->len) < 0
      && errno == EINVAL
      && epp->len != 8)
    write (epp->fd [1], &counter, (epp->len = 8));
#endif
}

static void
s_epipe_drain (s_epipe *epp)
{
  dTHX;
  char buf [9];

#ifdef _WIN32
  recv (epp->fd [0], buf, sizeof (buf), 0);
#else
  read (epp->fd [0], buf, sizeof (buf));
#endif
}

/* like new, but dups over old */
static int
s_epipe_renew (s_epipe *epp)
{
  dTHX;
  s_epipe epn;

  if (epp->fd [1] != epp->fd [0])
    close (epp->fd [1]);

  if (s_epipe_new (&epn))
    return -1;

  if (epp->len)
    {
      if (dup2 (epn.fd [0], epp->fd [0]) < 0)
        croak ("unable to dup over old event pipe"); /* should not croak */

      close (epn.fd [0]);

      if (epn.fd [0] == epn.fd [1])
        epn.fd [1] = epp->fd [0];

      epn.fd [0] = epp->fd [0];
    }

  *epp = epn;

  return 0;
}

#define s_epipe_fd(epp) ((epp)->fd [0])

static int
s_epipe_wait (s_epipe *epp)
{
  dTHX;
#ifdef _WIN32
  fd_set rfd;
  int fd = s_epipe_fd (epp);

  FD_ZERO (&rfd);
  FD_SET (fd, &rfd);

  return PerlSock_select (fd + 1, &rfd, 0, 0, 0);
#else
  /* poll is preferable on posix systems */
  struct pollfd pfd;

  pfd.fd = s_epipe_fd (epp);
  pfd.events = POLLIN;

  return poll (&pfd, 1, -1);
#endif
}

#endif

Revision:	1.8
Committed:	Wed Apr 14 00:17:22 2010 UTC (14 years, 1 month ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.7:	+4 -2 lines
Log Message:	strict(er?) aliasing
#	User	Rev	Content
1	root	1.1	#ifndef SCHMORP_PERL_H_
2			#define SCHMORP_PERL_H_
3
4	root	1.2	/* WARNING
5			* This header file is a shared resource between many modules.
6			*/
7
8	root	1.4	#include <signal.h>
9	root	1.5	#include <errno.h>
10	root	1.4
11			#ifndef _WIN32
12			# include <poll.h>
13			#endif
14
15	root	1.1	/* useful stuff, used by schmorp mostly */
16
17	root	1.2	#include "patchlevel.h"
18
19	root	1.1	#define PERL_VERSION_ATLEAST(a,b,c) \
20			(PERL_REVISION > (a) \
21			\|\| (PERL_REVISION == (a) \
22			&& (PERL_VERSION > (b) \
23			\|\| (PERL_VERSION == (b) && PERL_SUBVERSION >= (c)))))
24
25	root	1.7	#ifndef PERL_MAGIC_ext
26			# define PERL_MAGIC_ext '~'
27			#endif
28
29	root	1.1	#if !PERL_VERSION_ATLEAST (5,6,0)
30			# ifndef PL_ppaddr
31			# define PL_ppaddr ppaddr
32			# endif
33			# ifndef call_sv
34			# define call_sv perl_call_sv
35			# endif
36			# ifndef get_sv
37			# define get_sv perl_get_sv
38			# endif
39			# ifndef get_cv
40			# define get_cv perl_get_cv
41			# endif
42			# ifndef IS_PADGV
43			# define IS_PADGV(v) 0
44			# endif
45			# ifndef IS_PADCONST
46			# define IS_PADCONST(v) 0
47			# endif
48			#endif
49
50			/* 5.11 */
51			#ifndef CxHASARGS
52			# define CxHASARGS(cx) (cx)->blk_sub.hasargs
53			#endif
54
55			/* 5.10.0 */
56			#ifndef SvREFCNT_inc_NN
57			# define SvREFCNT_inc_NN(sv) SvREFCNT_inc (sv)
58			#endif
59
60			/* 5.8.8 */
61			#ifndef GV_NOTQUAL
62			# define GV_NOTQUAL 0
63			#endif
64			#ifndef newSV
65			# define newSV(l) NEWSV(0,l)
66			#endif
67			#ifndef CvISXSUB_on
68			# define CvISXSUB_on(cv) (void)cv
69			#endif
70			#ifndef CvISXSUB
71			# define CvISXSUB(cv) (CvXSUB (cv) ? TRUE : FALSE)
72			#endif
73			#ifndef Newx
74			# define Newx(ptr,nitems,type) New (0,ptr,nitems,type)
75			#endif
76
77			/* 5.8.7 */
78			#ifndef SvRV_set
79			# define SvRV_set(s,v) SvRV(s) = (v)
80			#endif
81
82			static int
83			s_signum (SV *sig)
84			{
85			#ifndef SIG_SIZE
86			/* kudos to Slaven Rezic for the idea */
87			static char sig_size [] = { SIG_NUM };
88			# define SIG_SIZE (sizeof (sig_size) + 1)
89			#endif
90	root	1.2	dTHX;
91	root	1.1	int signum;
92
93			SvGETMAGIC (sig);
94
95			for (signum = 1; signum < SIG_SIZE; ++signum)
96			if (strEQ (SvPV_nolen (sig), PL_sig_name [signum]))
97			return signum;
98
99			signum = SvIV (sig);
100
101			if (signum > 0 && signum < SIG_SIZE)
102			return signum;
103
104			return -1;
105			}
106
107			static int
108			s_signum_croak (SV *sig)
109			{
110			int signum = s_signum (sig);
111
112			if (signum < 0)
113	root	1.2	{
114			dTHX;
115			croak ("%s: invalid signal name or number", SvPV_nolen (sig));
116			}
117	root	1.1
118			return signum;
119			}
120
121			static int
122			s_fileno (SV *fh, int wr)
123			{
124	root	1.2	dTHX;
125	root	1.1	SvGETMAGIC (fh);
126
127			if (SvROK (fh))
128			{
129			fh = SvRV (fh);
130			SvGETMAGIC (fh);
131			}
132
133			if (SvTYPE (fh) == SVt_PVGV)
134			return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));
135
136			if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
137			return SvIV (fh);
138
139			return -1;
140			}
141
142			static int
143			s_fileno_croak (SV *fh, int wr)
144			{
145			int fd = s_fileno (fh, wr);
146
147			if (fd < 0)
148	root	1.2	{
149			dTHX;
150			croak ("%s: illegal fh argument, either not an OS file or read/write mode mismatch", SvPV_nolen (fh));
151			}
152	root	1.1
153			return fd;
154			}
155
156			static SV *
157			s_get_cv (SV *cb_sv)
158			{
159	root	1.2	dTHX;
160	root	1.1	HV *st;
161			GV *gvp;
162
163	root	1.2	return (SV *)sv_2cv (cb_sv, &st, &gvp, 0);
164	root	1.1	}
165
166			static SV *
167			s_get_cv_croak (SV *cb_sv)
168			{
169	root	1.2	SV *cv = s_get_cv (cb_sv);
170	root	1.1
171	root	1.2	if (!cv)
172			{
173			dTHX;
174			croak ("%s: callback must be a CODE reference or another callable object", SvPV_nolen (cb_sv));
175			}
176	root	1.1
177	root	1.2	return cv;
178	root	1.1	}
179
180			/*****************************************************************************/
181			/* gensub: simple closure generation utility */
182
183			#define S_GENSUB_ARG CvXSUBANY (cv).any_ptr
184
185			/* create a closure from XS, returns a code reference */
186			/* the arg can be accessed via GENSUB_ARG from the callback */
187			/* the callback must use dXSARGS/XSRETURN */
188			static SV *
189			s_gensub (pTHX_ void (xsub)(pTHX_ CV ), void *arg)
190			{
191			CV cv = (CV )newSV (0);
192
193			sv_upgrade ((SV *)cv, SVt_PVCV);
194
195			CvANON_on (cv);
196			CvISXSUB_on (cv);
197			CvXSUB (cv) = xsub;
198			S_GENSUB_ARG = arg;
199
200			return newRV_noinc ((SV *)cv);
201			}
202
203	root	1.4	/*****************************************************************************/
204			/* portable pipe/socketpair */
205	root	1.3
206			#ifdef USE_SOCKETS_AS_HANDLES
207	root	1.4	# define S_TO_HANDLE(x) ((HANDLE)win32_get_osfhandle (x))
208	root	1.3	#else
209	root	1.4	# define S_TO_HANDLE(x) ((HANDLE)x)
210	root	1.3	#endif
211
212			#ifdef _WIN32
213			/* taken almost verbatim from libev's ev_win32.c */
214			/* oh, the humanity! */
215			static int
216			s_pipe (int filedes [2])
217			{
218	root	1.6	dTHX;
219
220	root	1.3	struct sockaddr_in addr = { 0 };
221			int addr_size = sizeof (addr);
222			struct sockaddr_in adr2;
223			int adr2_size = sizeof (adr2);
224			SOCKET listener;
225			SOCKET sock [2] = { -1, -1 };
226
227			if ((listener = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
228			return -1;
229
230			addr.sin_family = AF_INET;
231			addr.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
232			addr.sin_port = 0;
233
234			if (bind (listener, (struct sockaddr *)&addr, addr_size))
235			goto fail;
236
237			if (getsockname (listener, (struct sockaddr *)&addr, &addr_size))
238			goto fail;
239
240			if (listen (listener, 1))
241			goto fail;
242
243			if ((sock [0] = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
244			goto fail;
245
246			if (connect (sock [0], (struct sockaddr *)&addr, addr_size))
247			goto fail;
248
249			if ((sock [1] = accept (listener, 0, 0)) < 0)
250			goto fail;
251
252			/* windows vista returns fantasy port numbers for getpeername.
253			* example for two interconnected tcp sockets:
254			*
255			* (Socket::unpack_sockaddr_in getsockname $sock0)[0] == 53364
256			* (Socket::unpack_sockaddr_in getpeername $sock0)[0] == 53363
257			* (Socket::unpack_sockaddr_in getsockname $sock1)[0] == 53363
258			* (Socket::unpack_sockaddr_in getpeername $sock1)[0] == 53365
259			*
260			* wow! tridirectional sockets!
261			*
262			* this way of checking ports seems to work:
263			*/
264			if (getpeername (sock [0], (struct sockaddr *)&addr, &addr_size))
265			goto fail;
266
267			if (getsockname (sock [1], (struct sockaddr *)&adr2, &adr2_size))
268			goto fail;
269
270			errno = WSAEINVAL;
271			if (addr_size != adr2_size
272			\|\| addr.sin_addr.s_addr != adr2.sin_addr.s_addr /* just to be sure, I mean, it's windows */
273			\|\| addr.sin_port != adr2.sin_port)
274			goto fail;
275
276			closesocket (listener);
277
278			#ifdef USE_SOCKETS_AS_HANDLES
279			/* when select isn't winsocket, we also expect socket, connect, accept etc.
280			* to work on fds */
281			filedes [0] = sock [0];
282			filedes [1] = sock [1];
283			#else
284			filedes [0] = _open_osfhandle (sock [0], 0);
285			filedes [1] = _open_osfhandle (sock [1], 0);
286			#endif
287
288			return 0;
289
290			fail:
291			closesocket (listener);
292
293			if (sock [0] != INVALID_SOCKET) closesocket (sock [0]);
294			if (sock [1] != INVALID_SOCKET) closesocket (sock [1]);
295
296			return -1;
297			}
298
299			#define s_socketpair(domain,type,protocol,filedes) s_pipe (filedes)
300
301	root	1.4	static int
302			s_fd_blocking (int fd, int blocking)
303			{
304			u_long nonblocking = !blocking;
305
306			return ioctlsocket ((SOCKET)S_TO_HANDLE (fd), FIONBIO, &nonblocking);
307			}
308
309			#define s_fd_prepare(fd) s_fd_blocking (fd, 0)
310
311	root	1.3	#else
312
313			#define s_socketpair(domain,type,protocol,filedes) socketpair (domain, type, protocol, filedes)
314			#define s_pipe(filedes) pipe (filedes)
315
316	root	1.4	static int
317			s_fd_blocking (int fd, int blocking)
318			{
319			return fcntl (fd, F_SETFL, blocking ? 0 : O_NONBLOCK);
320			}
321
322			static int
323			s_fd_prepare (int fd)
324			{
325			return s_fd_blocking (fd, 0)
326			\|\| fcntl (fd, F_SETFD, FD_CLOEXEC);
327			}
328
329			#endif
330
331			#if __linux && (__GLIBC__ > 2 \|\| (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
332			/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
333			# include <stdint.h>
334			# ifdef __cplusplus
335			extern "C" {
336			# endif
337			int eventfd (unsigned int initval, int flags);
338			# ifdef __cplusplus
339			}
340			# endif
341			#else
342			# define eventfd(initval,flags) -1
343			#endif
344
345			typedef struct {
346			int fd[2]; /* read, write fd, might be equal */
347			int len; /* write length (1 pipe/socket, 8 eventfd) */
348			} s_epipe;
349
350			static int
351			s_epipe_new (s_epipe *epp)
352			{
353			s_epipe ep;
354
355			ep.fd [0] = ep.fd [1] = eventfd (0, 0);
356
357			if (ep.fd [0] >= 0)
358			{
359			s_fd_prepare (ep.fd [0]);
360			ep.len = 8;
361			}
362			else
363			{
364			if (s_pipe (ep.fd))
365			return -1;
366
367			if (s_fd_prepare (ep.fd [0])
368			\|\| s_fd_prepare (ep.fd [1]))
369			{
370	root	1.6	dTHX;
371
372	root	1.4	close (ep.fd [0]);
373			close (ep.fd [1]);
374			return -1;
375			}
376
377			ep.len = 1;
378			}
379
380			*epp = ep;
381			return 0;
382			}
383
384			static void
385			s_epipe_destroy (s_epipe *epp)
386			{
387	root	1.6	dTHX;
388
389	root	1.4	close (epp->fd [0]);
390
391			if (epp->fd [1] != epp->fd [0])
392			close (epp->fd [1]);
393
394			epp->len = 0;
395			}
396
397			static void
398			s_epipe_signal (s_epipe *epp)
399			{
400			#ifdef _WIN32
401	root	1.6	/* perl overrides send with a function that crashes in other threads.
402			* unfortunately, it overrides it with an argument-less macro, so
403			* there is no way to force usage of the real send function.
404			* incompetent windows programmers - is this redundant?
405			*/
406			DWORD dummy;
407			WriteFile (S_TO_HANDLE (epp->fd [1]), (LPCVOID)&dummy, 1, &dummy, 0);
408	root	1.4	#else
409	root	1.6	static uint64_t counter = 1;
410			/* some modules accept fd's from outside, support eventfd here */
411			if (write (epp->fd [1], &counter, epp->len) < 0
412			&& errno == EINVAL
413			&& epp->len != 8)
414			write (epp->fd [1], &counter, (epp->len = 8));
415	root	1.4	#endif
416			}
417
418			static void
419			s_epipe_drain (s_epipe *epp)
420			{
421	root	1.6	dTHX;
422	root	1.4	char buf [9];
423
424			#ifdef _WIN32
425			recv (epp->fd [0], buf, sizeof (buf), 0);
426			#else
427			read (epp->fd [0], buf, sizeof (buf));
428	root	1.3	#endif
429	root	1.4	}
430
431			/* like new, but dups over old */
432			static int
433			s_epipe_renew (s_epipe *epp)
434			{
435	root	1.6	dTHX;
436	root	1.4	s_epipe epn;
437
438			if (epp->fd [1] != epp->fd [0])
439			close (epp->fd [1]);
440
441			if (s_epipe_new (&epn))
442			return -1;
443
444			if (epp->len)
445			{
446			if (dup2 (epn.fd [0], epp->fd [0]) < 0)
447			croak ("unable to dup over old event pipe"); /* should not croak */
448
449	root	1.8	close (epn.fd [0]);
450
451			if (epn.fd [0] == epn.fd [1])
452			epn.fd [1] = epp->fd [0];
453	root	1.4
454			epn.fd [0] = epp->fd [0];
455			}
456
457			*epp = epn;
458
459			return 0;
460			}
461
462			#define s_epipe_fd(epp) ((epp)->fd [0])
463
464			static int
465			s_epipe_wait (s_epipe *epp)
466			{
467	root	1.6	dTHX;
468	root	1.4	#ifdef _WIN32
469			fd_set rfd;
470			int fd = s_epipe_fd (epp);
471
472			FD_ZERO (&rfd);
473			FD_SET (fd, &rfd);
474
475			return PerlSock_select (fd + 1, &rfd, 0, 0, 0);
476			#else
477			/* poll is preferable on posix systems */
478			struct pollfd pfd;
479
480			pfd.fd = s_epipe_fd (epp);
481			pfd.events = POLLIN;
482
483	root	1.7	return poll (&pfd, 1, -1);
484	root	1.4	#endif
485			}
486
487	root	1.1	#endif
488