Async-Interrupt/Interrupt.xs

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

typedef volatile sig_atomic_t atomic_t;

static int *sig_pending, *psig_pend; /* make local copies because of missing THX */
static Sighandler_t old_sighandler;
static atomic_t async_pending;

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

#if defined(HAS_SIGACTION) && defined(SA_SIGINFO)
# define HAS_SA_SIGINFO 1
#endif

#if !PERL_VERSION_ATLEAST(5,10,0)
# undef HAS_SA_SIGINFO
#endif

/*****************************************************************************/
/* support stuff, copied from EV.xs mostly */

static int
extract_fd (SV *fh, int wr)
{
  int fd = PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));

  if (fd < 0)
    croak ("illegal fh argument, either not an OS file or read/write mode mismatch");

  return fd;
}

static SV *
get_cb (SV *cb_sv)
{
  HV *st;
  GV *gvp;
  CV *cv;

  if (!SvOK (cb_sv))
    return 0;

  cv = sv_2cv (cb_sv, &st, &gvp, 0);

  if (!cv)
    croak ("Async::Interrupt callback must be undef or a CODE reference");

  return (SV *)cv;
}

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

static int
sv_signum (SV *sig)
{
  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;
}

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

typedef struct {
  SV *cb;
  void (*c_cb)(pTHX_ void *c_arg, int value);
  void *c_arg;
  SV *fh_r, *fh_w;
  int blocked;
  int signum;

  int fd_r, fd_w;
  int fd_wlen;
  atomic_t fd_enable;
  atomic_t value;
  atomic_t pending;
} async_t;

static AV *asyncs;
static async_t *sig_async [SIG_SIZE];

#define SvASYNC_nrv(sv) INT2PTR (async_t *, SvIVX (sv))
#define SvASYNC(rv)     SvASYNC_nrv (SvRV (rv))

/* the main workhorse to signal */
static void
async_signal (void *signal_arg, int value)
{
  static char pipedata [8];

  async_t *async = (async_t *)signal_arg;
  int pending = async->pending;

  async->value   = value;
  async->pending = 1;
  async_pending  = 1;
  psig_pend [9]  = 1;
  *sig_pending   = 1;

  if (!pending && async->fd_w >= 0 && async->fd_enable)
    if (write (async->fd_w, pipedata, async->fd_wlen) < 0 && errno == EINVAL)
      /* on EINVAL we assume it's an eventfd */
      write (async->fd_w, pipedata, (async->fd_wlen = 8));
}

static void
handle_async (async_t *async)
{
  int old_errno = errno;
  int value = async->value;

  async->pending = 0;

  /* drain pipe */
  if (async->fd_r >= 0 && async->fd_enable)
    {
      char dummy [9]; /* 9 is enough for eventfd and normal pipes */

      while (read (async->fd_r, dummy, sizeof (dummy)) == sizeof (dummy))
        ;
    }

  if (async->c_cb)
    {
      dTHX;
      async->c_cb (aTHX_ async->c_arg, value);
    }

  if (async->cb)
    {
      dSP;

      SV *saveerr = SvOK (ERRSV) ? sv_mortalcopy (ERRSV) : 0;
      SV *savedie = PL_diehook;

      PL_diehook = 0;

      PUSHSTACKi (PERLSI_SIGNAL);

      PUSHMARK (SP);
      XPUSHs (sv_2mortal (newSViv (value)));
      PUTBACK;
      call_sv (async->cb, G_VOID | G_DISCARD | G_EVAL);

      if (SvTRUE (ERRSV))
        {
          SPAGAIN;

          PUSHMARK (SP);
          PUTBACK;
          call_sv (get_sv ("Async::Interrupt::DIED", 1), G_VOID | G_DISCARD | G_EVAL | G_KEEPERR);

          sv_setpvn (ERRSV, "", 0);
        }

      if (saveerr)
        sv_setsv (ERRSV, saveerr);

      {
        SV *oldhook = PL_diehook;
        PL_diehook = savedie;
        SvREFCNT_dec (oldhook);
      }

      POPSTACK;
    }

  errno = old_errno;
}

static void
handle_asyncs (void)
{
  int i;

  async_pending = 0;

  for (i = AvFILLp (asyncs); i >= 0; --i)
    {
      async_t *async = SvASYNC_nrv (AvARRAY (asyncs)[i]);

      if (async->pending && !async->blocked)
        handle_async (async);
    }
}

#if HAS_SA_SIGINFO
static Signal_t async_sighandler (int signum, siginfo_t *si, void *sarg)
{
  if (signum == 9)
    handle_asyncs ();
  else
    old_sighandler (signum, si, sarg);
}
#else
static Signal_t async_sighandler (int signum)
{
  if (signum == 9)
    handle_asyncs ();
  else
    old_sighandler (signum);
}
#endif

static void
async_sigsend (int signum)
{
  async_signal (sig_async [signum], 0);
}

static void
scope_block_cb (pTHX_ void *async_sv)
{
  async_t *async = SvASYNC_nrv ((SV *)async_sv);

  --async->blocked;
  if (async->pending && !async->blocked)
    handle_async (async);

  SvREFCNT_dec (async_sv);
}

MODULE = Async::Interrupt               PACKAGE = Async::Interrupt

BOOT:
        old_sighandler = PL_sighandlerp;
        PL_sighandlerp = async_sighandler;
        sig_pending = &PL_sig_pending;
        psig_pend   = PL_psig_pend;
        asyncs      = newAV ();
        CvNODEBUG_on (get_cv ("Async::Interrupt::scope_block", 0)); /* otherwise calling scope can be the debugger */

PROTOTYPES: DISABLE

void
_alloc (SV *cb, void *c_cb, void *c_arg, SV *fh_r, SV *fh_w, SV *signl)
        PPCODE:
{
        SV *cv   = SvOK (cb) ? SvREFCNT_inc (get_cb (cb)) : 0;
        int fd_r = SvOK (fh_r) ? extract_fd (fh_r, 0) : -1;
        int fd_w = SvOK (fh_w) ? extract_fd (fh_w, 1) : -1;
        async_t *async;

        Newz (0, async, 1, async_t);

        XPUSHs (sv_2mortal (newSViv (PTR2IV (async))));
        av_push (asyncs, TOPs);

        async->fh_r      = fd_r >= 0 ? newSVsv (fh_r) : 0; async->fd_r = fd_r;
        async->fh_w      = fd_w >= 0 ? newSVsv (fh_w) : 0; async->fd_w = fd_w;
        async->fd_wlen   = 1;
        async->fd_enable = 1;
        async->cb        = cv;
        async->c_cb      = c_cb;
        async->c_arg     = c_arg;
        SvGETMAGIC (signl);
        async->signum    = SvOK (signl) ? sv_signum (signl) : 0;

        if (async->signum)
          {
            if (async->signum < 0)
              croak ("Async::Interrupt::new got passed illegal signal name or number: %s", SvPV_nolen (signl));

            sig_async [async->signum] = async;
#if _WIN32
            signal (async->signum, async_sigsend);
#else
            {
              struct sigaction sa = { };
              sa.sa_handler = async_sigsend;
              sigfillset (&sa.sa_mask);
              sigaction (async->signum, &sa, 0);
            }
#endif
          }
}

void
signal_func (async_t *async)
        PPCODE:
        EXTEND (SP, 2);
        PUSHs (sv_2mortal (newSViv (PTR2IV (async_signal))));
        PUSHs (sv_2mortal (newSViv (PTR2IV (async))));

void
signal (async_t *async, int value = 0)
        CODE:
        async_signal (async, value);

void
block (async_t *async)
        CODE:
        ++async->blocked;

void
unblock (async_t *async)
        CODE:
        --async->blocked;
        if (async->pending && !async->blocked)
          handle_async (async);

void
scope_block (SV *self)
        CODE:
{
        SV *async_sv = SvRV (self);
        async_t *async = SvASYNC_nrv (async_sv);
        ++async->blocked;

        LEAVE; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
        SAVEDESTRUCTOR_X (scope_block_cb, (void *)SvREFCNT_inc (async_sv));
        ENTER; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
}

void
pipe_enable (async_t *async)
        ALIAS:
        pipe_enable = 1
        pipe_disable = 0
        CODE:
        async->fd_enable = ix;

void
DESTROY (SV *self)
        CODE:
{
        int i;
        SV *async_sv = SvRV (self);
        async_t *async = SvASYNC_nrv (async_sv);

        for (i = AvFILLp (asyncs); i >= 0; --i)
          if (AvARRAY (asyncs)[i] == async_sv)
            {
              if (i < AvFILLp (asyncs))
                AvARRAY (asyncs)[i] = AvARRAY (asyncs)[AvFILLp (asyncs)];

              assert (av_pop (asyncs) == async_sv);
              goto found;
            }

        if (!PL_dirty)
          warn ("Async::Interrupt::DESTROY could not find async object in list of asyncs, please report");

        found:

        if (async->signum)
          {
#if _WIN32
            signal (async->signum, SIG_DFL);
#else
            {
              struct sigaction sa = { };
              sa.sa_handler = SIG_DFL;
              sigaction (async->signum, &sa, 0);
            }
#endif
          }

        SvREFCNT_dec (async->fh_r);
        SvREFCNT_dec (async->fh_w);
        SvREFCNT_dec (async->cb);

        Safefree (async);
}

Revision:	1.6
Committed:	Sat Jul 11 22:16:50 2009 UTC (17 years, 2 months ago) by root
Branch:	MAIN
CVS Tags:	rel-0_041, rel-0_04
Changes since 1.5:	+122 -41 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	#include "EXTERN.h"
2			#include "perl.h"
3			#include "XSUB.h"
4
5			typedef volatile sig_atomic_t atomic_t;
6
7			static int sig_pending, psig_pend; /* make local copies because of missing THX */
8			static Sighandler_t old_sighandler;
9			static atomic_t async_pending;
10
11	root	1.5	#define PERL_VERSION_ATLEAST(a,b,c) \
12			(PERL_REVISION > (a) \
13			\|\| (PERL_REVISION == (a) \
14			&& (PERL_VERSION > (b) \
15			\|\| (PERL_VERSION == (b) && PERL_SUBVERSION >= (c)))))
16
17			#if defined(HAS_SIGACTION) && defined(SA_SIGINFO)
18			# define HAS_SA_SIGINFO 1
19			#endif
20
21			#if !PERL_VERSION_ATLEAST(5,10,0)
22			# undef HAS_SA_SIGINFO
23			#endif
24
25	root	1.6	/*****************************************************************************/
26			/* support stuff, copied from EV.xs mostly */
27
28	root	1.1	static int
29			extract_fd (SV *fh, int wr)
30			{
31			int fd = PerlIO_fileno (wr ? IoOFP (sv_2io (fh)) : IoIFP (sv_2io (fh)));
32
33			if (fd < 0)
34			croak ("illegal fh argument, either not an OS file or read/write mode mismatch");
35
36			return fd;
37			}
38
39			static SV *
40			get_cb (SV *cb_sv)
41			{
42			HV *st;
43			GV *gvp;
44			CV *cv;
45
46			if (!SvOK (cb_sv))
47			return 0;
48
49			cv = sv_2cv (cb_sv, &st, &gvp, 0);
50
51			if (!cv)
52			croak ("Async::Interrupt callback must be undef or a CODE reference");
53
54			return (SV *)cv;
55			}
56
57	root	1.6	#ifndef SIG_SIZE
58			/* kudos to Slaven Rezic for the idea */
59			static char sig_size [] = { SIG_NUM };
60			# define SIG_SIZE (sizeof (sig_size) + 1)
61			#endif
62
63			static int
64			sv_signum (SV *sig)
65			{
66			int signum;
67
68			SvGETMAGIC (sig);
69
70			for (signum = 1; signum < SIG_SIZE; ++signum)
71			if (strEQ (SvPV_nolen (sig), PL_sig_name [signum]))
72			return signum;
73
74			signum = SvIV (sig);
75
76			if (signum > 0 && signum < SIG_SIZE)
77			return signum;
78
79			return -1;
80			}
81
82			/*****************************************************************************/
83	root	1.1
84	root	1.6	typedef struct {
85	root	1.1	SV *cb;
86	root	1.2	void (c_cb)(pTHX_ void c_arg, int value);
87			void *c_arg;
88			SV fh_r, fh_w;
89			int blocked;
90	root	1.6	int signum;
91	root	1.1
92	root	1.2	int fd_r, fd_w;
93	root	1.6	int fd_wlen;
94			atomic_t fd_enable;
95	root	1.1	atomic_t value;
96	root	1.2	atomic_t pending;
97	root	1.6	} async_t;
98
99			static AV *asyncs;
100			static async_t *sig_async [SIG_SIZE];
101
102			#define SvASYNC_nrv(sv) INT2PTR (async_t *, SvIVX (sv))
103			#define SvASYNC(rv) SvASYNC_nrv (SvRV (rv))
104	root	1.1
105			/* the main workhorse to signal */
106			static void
107			async_signal (void *signal_arg, int value)
108			{
109	root	1.6	static char pipedata [8];
110
111			async_t async = (async_t )signal_arg;
112	root	1.2	int pending = async->pending;
113	root	1.1
114	root	1.2	async->value = value;
115			async->pending = 1;
116			async_pending = 1;
117			psig_pend [9] = 1;
118			*sig_pending = 1;
119	root	1.1
120	root	1.6	if (!pending && async->fd_w >= 0 && async->fd_enable)
121			if (write (async->fd_w, pipedata, async->fd_wlen) < 0 && errno == EINVAL)
122			/* on EINVAL we assume it's an eventfd */
123			write (async->fd_w, pipedata, (async->fd_wlen = 8));
124	root	1.2	}
125
126			static void
127	root	1.6	handle_async (async_t *async)
128	root	1.2	{
129			int old_errno = errno;
130			int value = async->value;
131
132			async->pending = 0;
133
134			/* drain pipe */
135	root	1.6	if (async->fd_r >= 0 && async->fd_enable)
136	root	1.1	{
137	root	1.6	char dummy [9]; /* 9 is enough for eventfd and normal pipes */
138	root	1.2
139			while (read (async->fd_r, dummy, sizeof (dummy)) == sizeof (dummy))
140			;
141			}
142
143			if (async->c_cb)
144			{
145			dTHX;
146			async->c_cb (aTHX_ async->c_arg, value);
147			}
148
149			if (async->cb)
150			{
151			dSP;
152
153			SV *saveerr = SvOK (ERRSV) ? sv_mortalcopy (ERRSV) : 0;
154			SV *savedie = PL_diehook;
155
156			PL_diehook = 0;
157
158			PUSHSTACKi (PERLSI_SIGNAL);
159
160			PUSHMARK (SP);
161			XPUSHs (sv_2mortal (newSViv (value)));
162			PUTBACK;
163			call_sv (async->cb, G_VOID \| G_DISCARD \| G_EVAL);
164
165			if (SvTRUE (ERRSV))
166			{
167			SPAGAIN;
168
169			PUSHMARK (SP);
170			PUTBACK;
171			call_sv (get_sv ("Async::Interrupt::DIED", 1), G_VOID \| G_DISCARD \| G_EVAL \| G_KEEPERR);
172
173			sv_setpvn (ERRSV, "", 0);
174			}
175
176			if (saveerr)
177			sv_setsv (ERRSV, saveerr);
178	root	1.1
179	root	1.2	{
180			SV *oldhook = PL_diehook;
181			PL_diehook = savedie;
182			SvREFCNT_dec (oldhook);
183			}
184
185			POPSTACK;
186	root	1.1	}
187
188	root	1.2	errno = old_errno;
189	root	1.1	}
190
191			static void
192	root	1.2	handle_asyncs (void)
193	root	1.1	{
194	root	1.2	int i;
195
196	root	1.1	async_pending = 0;
197	root	1.2
198			for (i = AvFILLp (asyncs); i >= 0; --i)
199			{
200	root	1.6	async_t *async = SvASYNC_nrv (AvARRAY (asyncs)[i]);
201	root	1.2
202			if (async->pending && !async->blocked)
203			handle_async (async);
204			}
205	root	1.1	}
206
207	root	1.5	#if HAS_SA_SIGINFO
208	root	1.1	static Signal_t async_sighandler (int signum, siginfo_t si, void sarg)
209			{
210			if (signum == 9)
211	root	1.2	handle_asyncs ();
212	root	1.1	else
213			old_sighandler (signum, si, sarg);
214			}
215			#else
216	root	1.3	static Signal_t async_sighandler (int signum)
217	root	1.1	{
218			if (signum == 9)
219	root	1.3	handle_asyncs ();
220	root	1.1	else
221			old_sighandler (signum);
222			}
223			#endif
224
225	root	1.4	static void
226	root	1.6	async_sigsend (int signum)
227			{
228			async_signal (sig_async [signum], 0);
229			}
230
231			static void
232	root	1.4	scope_block_cb (pTHX_ void *async_sv)
233			{
234	root	1.6	async_t async = SvASYNC_nrv ((SV )async_sv);
235	root	1.4
236			--async->blocked;
237			if (async->pending && !async->blocked)
238			handle_async (async);
239
240			SvREFCNT_dec (async_sv);
241			}
242	root	1.1
243			MODULE = Async::Interrupt PACKAGE = Async::Interrupt
244
245			BOOT:
246			old_sighandler = PL_sighandlerp;
247			PL_sighandlerp = async_sighandler;
248			sig_pending = &PL_sig_pending;
249			psig_pend = PL_psig_pend;
250			asyncs = newAV ();
251	root	1.4	CvNODEBUG_on (get_cv ("Async::Interrupt::scope_block", 0)); /* otherwise calling scope can be the debugger */
252	root	1.1
253	root	1.3	PROTOTYPES: DISABLE
254
255	root	1.6	void
256			_alloc (SV cb, void c_cb, void c_arg, SV fh_r, SV fh_w, SV signl)
257			PPCODE:
258	root	1.1	{
259	root	1.5	SV *cv = SvOK (cb) ? SvREFCNT_inc (get_cb (cb)) : 0;
260	root	1.2	int fd_r = SvOK (fh_r) ? extract_fd (fh_r, 0) : -1;
261			int fd_w = SvOK (fh_w) ? extract_fd (fh_w, 1) : -1;
262	root	1.6	async_t *async;
263	root	1.1
264	root	1.6	Newz (0, async, 1, async_t);
265	root	1.1
266	root	1.6	XPUSHs (sv_2mortal (newSViv (PTR2IV (async))));
267			av_push (asyncs, TOPs);
268	root	1.2
269	root	1.6	async->fh_r = fd_r >= 0 ? newSVsv (fh_r) : 0; async->fd_r = fd_r;
270			async->fh_w = fd_w >= 0 ? newSVsv (fh_w) : 0; async->fd_w = fd_w;
271			async->fd_wlen = 1;
272			async->fd_enable = 1;
273			async->cb = cv;
274			async->c_cb = c_cb;
275			async->c_arg = c_arg;
276			SvGETMAGIC (signl);
277			async->signum = SvOK (signl) ? sv_signum (signl) : 0;
278
279			if (async->signum)
280			{
281			if (async->signum < 0)
282			croak ("Async::Interrupt::new got passed illegal signal name or number: %s", SvPV_nolen (signl));
283
284			sig_async [async->signum] = async;
285			#if _WIN32
286			signal (async->signum, async_sigsend);
287			#else
288			{
289			struct sigaction sa = { };
290			sa.sa_handler = async_sigsend;
291			sigfillset (&sa.sa_mask);
292			sigaction (async->signum, &sa, 0);
293			}
294			#endif
295			}
296	root	1.1	}
297
298			void
299	root	1.6	signal_func (async_t *async)
300	root	1.1	PPCODE:
301			EXTEND (SP, 2);
302			PUSHs (sv_2mortal (newSViv (PTR2IV (async_signal))));
303	root	1.6	PUSHs (sv_2mortal (newSViv (PTR2IV (async))));
304	root	1.1
305			void
306	root	1.6	signal (async_t *async, int value = 0)
307	root	1.1	CODE:
308	root	1.6	async_signal (async, value);
309	root	1.2
310			void
311	root	1.6	block (async_t *async)
312	root	1.2	CODE:
313			++async->blocked;
314
315			void
316	root	1.6	unblock (async_t *async)
317	root	1.2	CODE:
318			--async->blocked;
319			if (async->pending && !async->blocked)
320			handle_async (async);
321	root	1.1
322			void
323	root	1.4	scope_block (SV *self)
324			CODE:
325			{
326			SV *async_sv = SvRV (self);
327	root	1.6	async_t *async = SvASYNC_nrv (async_sv);
328	root	1.4	++async->blocked;
329
330			LEAVE; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
331			SAVEDESTRUCTOR_X (scope_block_cb, (void *)SvREFCNT_inc (async_sv));
332			ENTER; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
333			}
334
335			void
336	root	1.6	pipe_enable (async_t *async)
337			ALIAS:
338			pipe_enable = 1
339			pipe_disable = 0
340			CODE:
341			async->fd_enable = ix;
342
343			void
344	root	1.1	DESTROY (SV *self)
345			CODE:
346			{
347			int i;
348			SV *async_sv = SvRV (self);
349	root	1.6	async_t *async = SvASYNC_nrv (async_sv);
350	root	1.1
351	root	1.2	for (i = AvFILLp (asyncs); i >= 0; --i)
352	root	1.1	if (AvARRAY (asyncs)[i] == async_sv)
353			{
354			if (i < AvFILLp (asyncs))
355	root	1.3	AvARRAY (asyncs)[i] = AvARRAY (asyncs)[AvFILLp (asyncs)];
356	root	1.1
357			assert (av_pop (asyncs) == async_sv);
358			goto found;
359			}
360
361			if (!PL_dirty)
362	root	1.2	warn ("Async::Interrupt::DESTROY could not find async object in list of asyncs, please report");
363	root	1.1
364			found:
365	root	1.6
366			if (async->signum)
367			{
368			#if _WIN32
369			signal (async->signum, SIG_DFL);
370			#else
371			{
372			struct sigaction sa = { };
373			sa.sa_handler = SIG_DFL;
374			sigaction (async->signum, &sa, 0);
375			}
376			#endif
377			}
378
379	root	1.2	SvREFCNT_dec (async->fh_r);
380			SvREFCNT_dec (async->fh_w);
381	root	1.1	SvREFCNT_dec (async->cb);
382
383			Safefree (async);
384			}
385