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>

#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)))))

#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])
{
  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) */
  volatile sig_atomic_t sent;
} 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]))
        {
           close (ep.fd [0]);
           close (ep.fd [1]);
           return -1;
        }

      ep.len = 1;
    }

  ep.sent = 0;
  *epp = ep;
  return 0;
}

static void
s_epipe_destroy (s_epipe *epp)
{
  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)
{
  if (epp->sent)
    return;

  epp->sent = 1;
  {
#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;
    write (epp->fd [1], &counter, epp->len);
#endif
  }
}

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

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

  epp->sent = 0;
}

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

      if (epp->fd [1] != epp->fd [0])
        close (epn.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)
{
#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, 0);
#endif
}

#endif

Revision:	1.4
Committed:	Wed Jul 15 16:58:53 2009 UTC (14 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.3:	+186 -3 lines
Log Message:	* empty log message *
#	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
10			#ifndef _WIN32
11			# include <poll.h>
12			#endif
13
14	root	1.1	/* useful stuff, used by schmorp mostly */
15
16	root	1.2	#include "patchlevel.h"
17
18	root	1.1	#define PERL_VERSION_ATLEAST(a,b,c) \
19			(PERL_REVISION > (a) \
20			\|\| (PERL_REVISION == (a) \
21			&& (PERL_VERSION > (b) \
22			\|\| (PERL_VERSION == (b) && PERL_SUBVERSION >= (c)))))
23
24			#if !PERL_VERSION_ATLEAST (5,6,0)
25			# ifndef PL_ppaddr
26			# define PL_ppaddr ppaddr
27			# endif
28			# ifndef call_sv
29			# define call_sv perl_call_sv
30			# endif
31			# ifndef get_sv
32			# define get_sv perl_get_sv
33			# endif
34			# ifndef get_cv
35			# define get_cv perl_get_cv
36			# endif
37			# ifndef IS_PADGV
38			# define IS_PADGV(v) 0
39			# endif
40			# ifndef IS_PADCONST
41			# define IS_PADCONST(v) 0
42			# endif
43			#endif
44
45			/* 5.11 */
46			#ifndef CxHASARGS
47			# define CxHASARGS(cx) (cx)->blk_sub.hasargs
48			#endif
49
50			/* 5.10.0 */
51			#ifndef SvREFCNT_inc_NN
52			# define SvREFCNT_inc_NN(sv) SvREFCNT_inc (sv)
53			#endif
54
55			/* 5.8.8 */
56			#ifndef GV_NOTQUAL
57			# define GV_NOTQUAL 0
58			#endif
59			#ifndef newSV
60			# define newSV(l) NEWSV(0,l)
61			#endif
62			#ifndef CvISXSUB_on
63			# define CvISXSUB_on(cv) (void)cv
64			#endif
65			#ifndef CvISXSUB
66			# define CvISXSUB(cv) (CvXSUB (cv) ? TRUE : FALSE)
67			#endif
68			#ifndef Newx
69			# define Newx(ptr,nitems,type) New (0,ptr,nitems,type)
70			#endif
71
72			/* 5.8.7 */
73			#ifndef SvRV_set
74			# define SvRV_set(s,v) SvRV(s) = (v)
75			#endif
76
77			static int
78			s_signum (SV *sig)
79			{
80			#ifndef SIG_SIZE
81			/* kudos to Slaven Rezic for the idea */
82			static char sig_size [] = { SIG_NUM };
83			# define SIG_SIZE (sizeof (sig_size) + 1)
84			#endif
85	root	1.2	dTHX;
86	root	1.1	int signum;
87
88			SvGETMAGIC (sig);
89
90			for (signum = 1; signum < SIG_SIZE; ++signum)
91			if (strEQ (SvPV_nolen (sig), PL_sig_name [signum]))
92			return signum;
93
94			signum = SvIV (sig);
95
96			if (signum > 0 && signum < SIG_SIZE)
97			return signum;
98
99			return -1;
100			}
101
102			static int
103			s_signum_croak (SV *sig)
104			{
105			int signum = s_signum (sig);
106
107			if (signum < 0)
108	root	1.2	{
109			dTHX;
110			croak ("%s: invalid signal name or number", SvPV_nolen (sig));
111			}
112	root	1.1
113			return signum;
114			}
115
116			static int
117			s_fileno (SV *fh, int wr)
118			{
119	root	1.2	dTHX;
120	root	1.1	SvGETMAGIC (fh);
121
122			if (SvROK (fh))
123			{
124			fh = SvRV (fh);
125			SvGETMAGIC (fh);
126			}
127
128			if (SvTYPE (fh) == SVt_PVGV)
129			return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));
130
131			if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
132			return SvIV (fh);
133
134			return -1;
135			}
136
137			static int
138			s_fileno_croak (SV *fh, int wr)
139			{
140			int fd = s_fileno (fh, wr);
141
142			if (fd < 0)
143	root	1.2	{
144			dTHX;
145			croak ("%s: illegal fh argument, either not an OS file or read/write mode mismatch", SvPV_nolen (fh));
146			}
147	root	1.1
148			return fd;
149			}
150
151			static SV *
152			s_get_cv (SV *cb_sv)
153			{
154	root	1.2	dTHX;
155	root	1.1	HV *st;
156			GV *gvp;
157
158	root	1.2	return (SV *)sv_2cv (cb_sv, &st, &gvp, 0);
159	root	1.1	}
160
161			static SV *
162			s_get_cv_croak (SV *cb_sv)
163			{
164	root	1.2	SV *cv = s_get_cv (cb_sv);
165	root	1.1
166	root	1.2	if (!cv)
167			{
168			dTHX;
169			croak ("%s: callback must be a CODE reference or another callable object", SvPV_nolen (cb_sv));
170			}
171	root	1.1
172	root	1.2	return cv;
173	root	1.1	}
174
175			/*****************************************************************************/
176			/* gensub: simple closure generation utility */
177
178			#define S_GENSUB_ARG CvXSUBANY (cv).any_ptr
179
180			/* create a closure from XS, returns a code reference */
181			/* the arg can be accessed via GENSUB_ARG from the callback */
182			/* the callback must use dXSARGS/XSRETURN */
183			static SV *
184			s_gensub (pTHX_ void (xsub)(pTHX_ CV ), void *arg)
185			{
186			CV cv = (CV )newSV (0);
187
188			sv_upgrade ((SV *)cv, SVt_PVCV);
189
190			CvANON_on (cv);
191			CvISXSUB_on (cv);
192			CvXSUB (cv) = xsub;
193			S_GENSUB_ARG = arg;
194
195			return newRV_noinc ((SV *)cv);
196			}
197
198	root	1.4	/*****************************************************************************/
199			/* portable pipe/socketpair */
200	root	1.3
201			#ifdef USE_SOCKETS_AS_HANDLES
202	root	1.4	# define S_TO_HANDLE(x) ((HANDLE)win32_get_osfhandle (x))
203	root	1.3	#else
204	root	1.4	# define S_TO_HANDLE(x) ((HANDLE)x)
205	root	1.3	#endif
206
207			#ifdef _WIN32
208			/* taken almost verbatim from libev's ev_win32.c */
209			/* oh, the humanity! */
210			static int
211			s_pipe (int filedes [2])
212			{
213			struct sockaddr_in addr = { 0 };
214			int addr_size = sizeof (addr);
215			struct sockaddr_in adr2;
216			int adr2_size = sizeof (adr2);
217			SOCKET listener;
218			SOCKET sock [2] = { -1, -1 };
219
220			if ((listener = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
221			return -1;
222
223			addr.sin_family = AF_INET;
224			addr.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
225			addr.sin_port = 0;
226
227			if (bind (listener, (struct sockaddr *)&addr, addr_size))
228			goto fail;
229
230			if (getsockname (listener, (struct sockaddr *)&addr, &addr_size))
231			goto fail;
232
233			if (listen (listener, 1))
234			goto fail;
235
236			if ((sock [0] = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
237			goto fail;
238
239			if (connect (sock [0], (struct sockaddr *)&addr, addr_size))
240			goto fail;
241
242			if ((sock [1] = accept (listener, 0, 0)) < 0)
243			goto fail;
244
245			/* windows vista returns fantasy port numbers for getpeername.
246			* example for two interconnected tcp sockets:
247			*
248			* (Socket::unpack_sockaddr_in getsockname $sock0)[0] == 53364
249			* (Socket::unpack_sockaddr_in getpeername $sock0)[0] == 53363
250			* (Socket::unpack_sockaddr_in getsockname $sock1)[0] == 53363
251			* (Socket::unpack_sockaddr_in getpeername $sock1)[0] == 53365
252			*
253			* wow! tridirectional sockets!
254			*
255			* this way of checking ports seems to work:
256			*/
257			if (getpeername (sock [0], (struct sockaddr *)&addr, &addr_size))
258			goto fail;
259
260			if (getsockname (sock [1], (struct sockaddr *)&adr2, &adr2_size))
261			goto fail;
262
263			errno = WSAEINVAL;
264			if (addr_size != adr2_size
265			\|\| addr.sin_addr.s_addr != adr2.sin_addr.s_addr /* just to be sure, I mean, it's windows */
266			\|\| addr.sin_port != adr2.sin_port)
267			goto fail;
268
269			closesocket (listener);
270
271			#ifdef USE_SOCKETS_AS_HANDLES
272			/* when select isn't winsocket, we also expect socket, connect, accept etc.
273			* to work on fds */
274			filedes [0] = sock [0];
275			filedes [1] = sock [1];
276			#else
277			filedes [0] = _open_osfhandle (sock [0], 0);
278			filedes [1] = _open_osfhandle (sock [1], 0);
279			#endif
280
281			return 0;
282
283			fail:
284			closesocket (listener);
285
286			if (sock [0] != INVALID_SOCKET) closesocket (sock [0]);
287			if (sock [1] != INVALID_SOCKET) closesocket (sock [1]);
288
289			return -1;
290			}
291
292			#define s_socketpair(domain,type,protocol,filedes) s_pipe (filedes)
293
294	root	1.4	static int
295			s_fd_blocking (int fd, int blocking)
296			{
297			u_long nonblocking = !blocking;
298
299			return ioctlsocket ((SOCKET)S_TO_HANDLE (fd), FIONBIO, &nonblocking);
300			}
301
302			#define s_fd_prepare(fd) s_fd_blocking (fd, 0)
303
304	root	1.3	#else
305
306			#define s_socketpair(domain,type,protocol,filedes) socketpair (domain, type, protocol, filedes)
307			#define s_pipe(filedes) pipe (filedes)
308
309	root	1.4	static int
310			s_fd_blocking (int fd, int blocking)
311			{
312			return fcntl (fd, F_SETFL, blocking ? 0 : O_NONBLOCK);
313			}
314
315			static int
316			s_fd_prepare (int fd)
317			{
318			return s_fd_blocking (fd, 0)
319			\|\| fcntl (fd, F_SETFD, FD_CLOEXEC);
320			}
321
322			#endif
323
324			#if __linux && (__GLIBC__ > 2 \|\| (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
325			/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
326			# include <stdint.h>
327			# ifdef __cplusplus
328			extern "C" {
329			# endif
330			int eventfd (unsigned int initval, int flags);
331			# ifdef __cplusplus
332			}
333			# endif
334			#else
335			# define eventfd(initval,flags) -1
336			#endif
337
338			typedef struct {
339			int fd[2]; /* read, write fd, might be equal */
340			int len; /* write length (1 pipe/socket, 8 eventfd) */
341			volatile sig_atomic_t sent;
342			} s_epipe;
343
344			static int
345			s_epipe_new (s_epipe *epp)
346			{
347			s_epipe ep;
348
349			ep.fd [0] = ep.fd [1] = eventfd (0, 0);
350
351			if (ep.fd [0] >= 0)
352			{
353			s_fd_prepare (ep.fd [0]);
354			ep.len = 8;
355			}
356			else
357			{
358			if (s_pipe (ep.fd))
359			return -1;
360
361			if (s_fd_prepare (ep.fd [0])
362			\|\| s_fd_prepare (ep.fd [1]))
363			{
364			close (ep.fd [0]);
365			close (ep.fd [1]);
366			return -1;
367			}
368
369			ep.len = 1;
370			}
371
372			ep.sent = 0;
373			*epp = ep;
374			return 0;
375			}
376
377			static void
378			s_epipe_destroy (s_epipe *epp)
379			{
380			close (epp->fd [0]);
381
382			if (epp->fd [1] != epp->fd [0])
383			close (epp->fd [1]);
384
385			epp->len = 0;
386			}
387
388			static void
389			s_epipe_signal (s_epipe *epp)
390			{
391			if (epp->sent)
392			return;
393
394			epp->sent = 1;
395			{
396			#ifdef _WIN32
397			/* perl overrides send with a function that crashes in other threads.
398			* unfortunately, it overrides it with an argument-less macro, so
399			* there is no way to force usage of the real send function.
400			* incompetent windows programmers - is this redundant?
401			*/
402			DWORD dummy;
403			WriteFile (S_TO_HANDLE (epp->fd [1]), (LPCVOID)&dummy, 1, &dummy, 0);
404			#else
405			static uint64_t counter = 1;
406			write (epp->fd [1], &counter, epp->len);
407			#endif
408			}
409			}
410
411			static void
412			s_epipe_drain (s_epipe *epp)
413			{
414			char buf [9];
415
416			#ifdef _WIN32
417			recv (epp->fd [0], buf, sizeof (buf), 0);
418			#else
419			read (epp->fd [0], buf, sizeof (buf));
420	root	1.3	#endif
421
422	root	1.4	epp->sent = 0;
423			}
424
425			/* like new, but dups over old */
426			static int
427			s_epipe_renew (s_epipe *epp)
428			{
429			s_epipe epn;
430
431			if (epp->fd [1] != epp->fd [0])
432			close (epp->fd [1]);
433
434			if (s_epipe_new (&epn))
435			return -1;
436
437			if (epp->len)
438			{
439			if (dup2 (epn.fd [0], epp->fd [0]) < 0)
440			croak ("unable to dup over old event pipe"); /* should not croak */
441
442			if (epp->fd [1] != epp->fd [0])
443			close (epn.fd [0]);
444
445			epn.fd [0] = epp->fd [0];
446			}
447
448			*epp = epn;
449
450			return 0;
451			}
452
453			#define s_epipe_fd(epp) ((epp)->fd [0])
454
455			static int
456			s_epipe_wait (s_epipe *epp)
457			{
458			#ifdef _WIN32
459			fd_set rfd;
460			int fd = s_epipe_fd (epp);
461
462			FD_ZERO (&rfd);
463			FD_SET (fd, &rfd);
464
465			return PerlSock_select (fd + 1, &rfd, 0, 0, 0);
466			#else
467			/* poll is preferable on posix systems */
468			struct pollfd pfd;
469
470			pfd.fd = s_epipe_fd (epp);
471			pfd.events = POLLIN;
472
473			return poll (&pfd, 1, 0);
474			#endif
475			}
476
477	root	1.1	#endif
478