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)))))

#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;
    /* 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)
{
  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:	1.5
Committed:	Fri Jul 17 14:49:33 2009 UTC (14 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-3_7
Changes since 1.4:	+6 -1 lines
Log Message:	3.7
#	Content
1	#ifndef SCHMORP_PERL_H_
2	#define SCHMORP_PERL_H_
3
4	/* WARNING
5	* This header file is a shared resource between many modules.
6	*/
7
8	#include <signal.h>
9	#include <errno.h>
10
11	#ifndef _WIN32
12	# include <poll.h>
13	#endif
14
15	/* useful stuff, used by schmorp mostly */
16
17	#include "patchlevel.h"
18
19	#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	#if !PERL_VERSION_ATLEAST (5,6,0)
26	# ifndef PL_ppaddr
27	# define PL_ppaddr ppaddr
28	# endif
29	# ifndef call_sv
30	# define call_sv perl_call_sv
31	# endif
32	# ifndef get_sv
33	# define get_sv perl_get_sv
34	# endif
35	# ifndef get_cv
36	# define get_cv perl_get_cv
37	# endif
38	# ifndef IS_PADGV
39	# define IS_PADGV(v) 0
40	# endif
41	# ifndef IS_PADCONST
42	# define IS_PADCONST(v) 0
43	# endif
44	#endif
45
46	/* 5.11 */
47	#ifndef CxHASARGS
48	# define CxHASARGS(cx) (cx)->blk_sub.hasargs
49	#endif
50
51	/* 5.10.0 */
52	#ifndef SvREFCNT_inc_NN
53	# define SvREFCNT_inc_NN(sv) SvREFCNT_inc (sv)
54	#endif
55
56	/* 5.8.8 */
57	#ifndef GV_NOTQUAL
58	# define GV_NOTQUAL 0
59	#endif
60	#ifndef newSV
61	# define newSV(l) NEWSV(0,l)
62	#endif
63	#ifndef CvISXSUB_on
64	# define CvISXSUB_on(cv) (void)cv
65	#endif
66	#ifndef CvISXSUB
67	# define CvISXSUB(cv) (CvXSUB (cv) ? TRUE : FALSE)
68	#endif
69	#ifndef Newx
70	# define Newx(ptr,nitems,type) New (0,ptr,nitems,type)
71	#endif
72
73	/* 5.8.7 */
74	#ifndef SvRV_set
75	# define SvRV_set(s,v) SvRV(s) = (v)
76	#endif
77
78	static int
79	s_signum (SV *sig)
80	{
81	#ifndef SIG_SIZE
82	/* kudos to Slaven Rezic for the idea */
83	static char sig_size [] = { SIG_NUM };
84	# define SIG_SIZE (sizeof (sig_size) + 1)
85	#endif
86	dTHX;
87	int signum;
88
89	SvGETMAGIC (sig);
90
91	for (signum = 1; signum < SIG_SIZE; ++signum)
92	if (strEQ (SvPV_nolen (sig), PL_sig_name [signum]))
93	return signum;
94
95	signum = SvIV (sig);
96
97	if (signum > 0 && signum < SIG_SIZE)
98	return signum;
99
100	return -1;
101	}
102
103	static int
104	s_signum_croak (SV *sig)
105	{
106	int signum = s_signum (sig);
107
108	if (signum < 0)
109	{
110	dTHX;
111	croak ("%s: invalid signal name or number", SvPV_nolen (sig));
112	}
113
114	return signum;
115	}
116
117	static int
118	s_fileno (SV *fh, int wr)
119	{
120	dTHX;
121	SvGETMAGIC (fh);
122
123	if (SvROK (fh))
124	{
125	fh = SvRV (fh);
126	SvGETMAGIC (fh);
127	}
128
129	if (SvTYPE (fh) == SVt_PVGV)
130	return PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));
131
132	if (SvOK (fh) && (SvIV (fh) >= 0) && (SvIV (fh) < 0x7fffffffL))
133	return SvIV (fh);
134
135	return -1;
136	}
137
138	static int
139	s_fileno_croak (SV *fh, int wr)
140	{
141	int fd = s_fileno (fh, wr);
142
143	if (fd < 0)
144	{
145	dTHX;
146	croak ("%s: illegal fh argument, either not an OS file or read/write mode mismatch", SvPV_nolen (fh));
147	}
148
149	return fd;
150	}
151
152	static SV *
153	s_get_cv (SV *cb_sv)
154	{
155	dTHX;
156	HV *st;
157	GV *gvp;
158
159	return (SV *)sv_2cv (cb_sv, &st, &gvp, 0);
160	}
161
162	static SV *
163	s_get_cv_croak (SV *cb_sv)
164	{
165	SV *cv = s_get_cv (cb_sv);
166
167	if (!cv)
168	{
169	dTHX;
170	croak ("%s: callback must be a CODE reference or another callable object", SvPV_nolen (cb_sv));
171	}
172
173	return cv;
174	}
175
176	/*****************************************************************************/
177	/* gensub: simple closure generation utility */
178
179	#define S_GENSUB_ARG CvXSUBANY (cv).any_ptr
180
181	/* create a closure from XS, returns a code reference */
182	/* the arg can be accessed via GENSUB_ARG from the callback */
183	/* the callback must use dXSARGS/XSRETURN */
184	static SV *
185	s_gensub (pTHX_ void (xsub)(pTHX_ CV ), void *arg)
186	{
187	CV cv = (CV )newSV (0);
188
189	sv_upgrade ((SV *)cv, SVt_PVCV);
190
191	CvANON_on (cv);
192	CvISXSUB_on (cv);
193	CvXSUB (cv) = xsub;
194	S_GENSUB_ARG = arg;
195
196	return newRV_noinc ((SV *)cv);
197	}
198
199	/*****************************************************************************/
200	/* portable pipe/socketpair */
201
202	#ifdef USE_SOCKETS_AS_HANDLES
203	# define S_TO_HANDLE(x) ((HANDLE)win32_get_osfhandle (x))
204	#else
205	# define S_TO_HANDLE(x) ((HANDLE)x)
206	#endif
207
208	#ifdef _WIN32
209	/* taken almost verbatim from libev's ev_win32.c */
210	/* oh, the humanity! */
211	static int
212	s_pipe (int filedes [2])
213	{
214	struct sockaddr_in addr = { 0 };
215	int addr_size = sizeof (addr);
216	struct sockaddr_in adr2;
217	int adr2_size = sizeof (adr2);
218	SOCKET listener;
219	SOCKET sock [2] = { -1, -1 };
220
221	if ((listener = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
222	return -1;
223
224	addr.sin_family = AF_INET;
225	addr.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
226	addr.sin_port = 0;
227
228	if (bind (listener, (struct sockaddr *)&addr, addr_size))
229	goto fail;
230
231	if (getsockname (listener, (struct sockaddr *)&addr, &addr_size))
232	goto fail;
233
234	if (listen (listener, 1))
235	goto fail;
236
237	if ((sock [0] = socket (AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
238	goto fail;
239
240	if (connect (sock [0], (struct sockaddr *)&addr, addr_size))
241	goto fail;
242
243	if ((sock [1] = accept (listener, 0, 0)) < 0)
244	goto fail;
245
246	/* windows vista returns fantasy port numbers for getpeername.
247	* example for two interconnected tcp sockets:
248	*
249	* (Socket::unpack_sockaddr_in getsockname $sock0)[0] == 53364
250	* (Socket::unpack_sockaddr_in getpeername $sock0)[0] == 53363
251	* (Socket::unpack_sockaddr_in getsockname $sock1)[0] == 53363
252	* (Socket::unpack_sockaddr_in getpeername $sock1)[0] == 53365
253	*
254	* wow! tridirectional sockets!
255	*
256	* this way of checking ports seems to work:
257	*/
258	if (getpeername (sock [0], (struct sockaddr *)&addr, &addr_size))
259	goto fail;
260
261	if (getsockname (sock [1], (struct sockaddr *)&adr2, &adr2_size))
262	goto fail;
263
264	errno = WSAEINVAL;
265	if (addr_size != adr2_size
266	\|\| addr.sin_addr.s_addr != adr2.sin_addr.s_addr /* just to be sure, I mean, it's windows */
267	\|\| addr.sin_port != adr2.sin_port)
268	goto fail;
269
270	closesocket (listener);
271
272	#ifdef USE_SOCKETS_AS_HANDLES
273	/* when select isn't winsocket, we also expect socket, connect, accept etc.
274	* to work on fds */
275	filedes [0] = sock [0];
276	filedes [1] = sock [1];
277	#else
278	filedes [0] = _open_osfhandle (sock [0], 0);
279	filedes [1] = _open_osfhandle (sock [1], 0);
280	#endif
281
282	return 0;
283
284	fail:
285	closesocket (listener);
286
287	if (sock [0] != INVALID_SOCKET) closesocket (sock [0]);
288	if (sock [1] != INVALID_SOCKET) closesocket (sock [1]);
289
290	return -1;
291	}
292
293	#define s_socketpair(domain,type,protocol,filedes) s_pipe (filedes)
294
295	static int
296	s_fd_blocking (int fd, int blocking)
297	{
298	u_long nonblocking = !blocking;
299
300	return ioctlsocket ((SOCKET)S_TO_HANDLE (fd), FIONBIO, &nonblocking);
301	}
302
303	#define s_fd_prepare(fd) s_fd_blocking (fd, 0)
304
305	#else
306
307	#define s_socketpair(domain,type,protocol,filedes) socketpair (domain, type, protocol, filedes)
308	#define s_pipe(filedes) pipe (filedes)
309
310	static int
311	s_fd_blocking (int fd, int blocking)
312	{
313	return fcntl (fd, F_SETFL, blocking ? 0 : O_NONBLOCK);
314	}
315
316	static int
317	s_fd_prepare (int fd)
318	{
319	return s_fd_blocking (fd, 0)
320	\|\| fcntl (fd, F_SETFD, FD_CLOEXEC);
321	}
322
323	#endif
324
325	#if __linux && (__GLIBC__ > 2 \|\| (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7))
326	/* our minimum requirement is glibc 2.7 which has the stub, but not the header */
327	# include <stdint.h>
328	# ifdef __cplusplus
329	extern "C" {
330	# endif
331	int eventfd (unsigned int initval, int flags);
332	# ifdef __cplusplus
333	}
334	# endif
335	#else
336	# define eventfd(initval,flags) -1
337	#endif
338
339	typedef struct {
340	int fd[2]; /* read, write fd, might be equal */
341	int len; /* write length (1 pipe/socket, 8 eventfd) */
342	volatile sig_atomic_t sent;
343	} s_epipe;
344
345	static int
346	s_epipe_new (s_epipe *epp)
347	{
348	s_epipe ep;
349
350	ep.fd [0] = ep.fd [1] = eventfd (0, 0);
351
352	if (ep.fd [0] >= 0)
353	{
354	s_fd_prepare (ep.fd [0]);
355	ep.len = 8;
356	}
357	else
358	{
359	if (s_pipe (ep.fd))
360	return -1;
361
362	if (s_fd_prepare (ep.fd [0])
363	\|\| s_fd_prepare (ep.fd [1]))
364	{
365	close (ep.fd [0]);
366	close (ep.fd [1]);
367	return -1;
368	}
369
370	ep.len = 1;
371	}
372
373	ep.sent = 0;
374	*epp = ep;
375	return 0;
376	}
377
378	static void
379	s_epipe_destroy (s_epipe *epp)
380	{
381	close (epp->fd [0]);
382
383	if (epp->fd [1] != epp->fd [0])
384	close (epp->fd [1]);
385
386	epp->len = 0;
387	}
388
389	static void
390	s_epipe_signal (s_epipe *epp)
391	{
392	if (epp->sent)
393	return;
394
395	epp->sent = 1;
396	{
397	#ifdef _WIN32
398	/* perl overrides send with a function that crashes in other threads.
399	* unfortunately, it overrides it with an argument-less macro, so
400	* there is no way to force usage of the real send function.
401	* incompetent windows programmers - is this redundant?
402	*/
403	DWORD dummy;
404	WriteFile (S_TO_HANDLE (epp->fd [1]), (LPCVOID)&dummy, 1, &dummy, 0);
405	#else
406	static uint64_t counter = 1;
407	/* some modules accept fd's from outside, support eventfd here */
408	if (write (epp->fd [1], &counter, epp->len) < 0
409	&& errno == EINVAL
410	&& epp->len != 8)
411	write (epp->fd [1], &counter, (epp->len = 8));
412	#endif
413	}
414	}
415
416	static void
417	s_epipe_drain (s_epipe *epp)
418	{
419	char buf [9];
420
421	#ifdef _WIN32
422	recv (epp->fd [0], buf, sizeof (buf), 0);
423	#else
424	read (epp->fd [0], buf, sizeof (buf));
425	#endif
426
427	epp->sent = 0;
428	}
429
430	/* like new, but dups over old */
431	static int
432	s_epipe_renew (s_epipe *epp)
433	{
434	s_epipe epn;
435
436	if (epp->fd [1] != epp->fd [0])
437	close (epp->fd [1]);
438
439	if (s_epipe_new (&epn))
440	return -1;
441
442	if (epp->len)
443	{
444	if (dup2 (epn.fd [0], epp->fd [0]) < 0)
445	croak ("unable to dup over old event pipe"); /* should not croak */
446
447	if (epp->fd [1] != epp->fd [0])
448	close (epn.fd [0]);
449
450	epn.fd [0] = epp->fd [0];
451	}
452
453	*epp = epn;
454
455	return 0;
456	}
457
458	#define s_epipe_fd(epp) ((epp)->fd [0])
459
460	static int
461	s_epipe_wait (s_epipe *epp)
462	{
463	#ifdef _WIN32
464	fd_set rfd;
465	int fd = s_epipe_fd (epp);
466
467	FD_ZERO (&rfd);
468	FD_SET (fd, &rfd);
469
470	return PerlSock_select (fd + 1, &rfd, 0, 0, 0);
471	#else
472	/* poll is preferable on posix systems */
473	struct pollfd pfd;
474
475	pfd.fd = s_epipe_fd (epp);
476	pfd.events = POLLIN;
477
478	return poll (&pfd, 1, 0);
479	#endif
480	}
481
482	#endif
483