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 signum;
  volatile int blocked;

  int fd_r;
  volatile int 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;

  {
    int fd_w      = async->fd_w;
    int fd_enable = async->fd_enable;

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

#define block(async) ++(async)->blocked

static void
unblock (async_t *async)
{
  --async->blocked;
  if (async->pending && !async->blocked)
    handle_async (async);
}

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

void
unblock (async_t *async)
        CODE:
        unblock (async);

void
scope_block (SV *self)
        CODE:
{
        SV *async_sv = SvRV (self);
        async_t *async = SvASYNC_nrv (async_sv);
        block (async);

        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:	1.7
Committed:	Tue Jul 14 14:18:10 2009 UTC (14 years, 11 months ago) by root
Branch:	MAIN
Changes since 1.6:	+24 -14 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	root	1.6	int signum;
90	root	1.7	volatile int blocked;
91	root	1.1
92	root	1.7	int fd_r;
93			volatile int fd_w;
94	root	1.6	int fd_wlen;
95			atomic_t fd_enable;
96	root	1.1	atomic_t value;
97	root	1.2	atomic_t pending;
98	root	1.6	} async_t;
99
100			static AV *asyncs;
101			static async_t *sig_async [SIG_SIZE];
102
103			#define SvASYNC_nrv(sv) INT2PTR (async_t *, SvIVX (sv))
104			#define SvASYNC(rv) SvASYNC_nrv (SvRV (rv))
105	root	1.1
106			/* the main workhorse to signal */
107			static void
108			async_signal (void *signal_arg, int value)
109			{
110	root	1.6	static char pipedata [8];
111
112			async_t async = (async_t )signal_arg;
113	root	1.2	int pending = async->pending;
114	root	1.1
115	root	1.2	async->value = value;
116			async->pending = 1;
117			async_pending = 1;
118			psig_pend [9] = 1;
119			*sig_pending = 1;
120	root	1.1
121	root	1.7	{
122			int fd_w = async->fd_w;
123			int fd_enable = async->fd_enable;
124
125			if (!pending && fd_w >= 0 && fd_enable)
126			if (write (fd_w, pipedata, async->fd_wlen) < 0 && errno == EINVAL)
127			/* on EINVAL we assume it's an eventfd */
128			write (fd_w, pipedata, (async->fd_wlen = 8));
129			}
130	root	1.2	}
131
132			static void
133	root	1.6	handle_async (async_t *async)
134	root	1.2	{
135			int old_errno = errno;
136			int value = async->value;
137
138			async->pending = 0;
139
140			/* drain pipe */
141	root	1.6	if (async->fd_r >= 0 && async->fd_enable)
142	root	1.1	{
143	root	1.6	char dummy [9]; /* 9 is enough for eventfd and normal pipes */
144	root	1.2
145			while (read (async->fd_r, dummy, sizeof (dummy)) == sizeof (dummy))
146			;
147			}
148
149			if (async->c_cb)
150			{
151			dTHX;
152			async->c_cb (aTHX_ async->c_arg, value);
153			}
154
155			if (async->cb)
156			{
157			dSP;
158
159			SV *saveerr = SvOK (ERRSV) ? sv_mortalcopy (ERRSV) : 0;
160			SV *savedie = PL_diehook;
161
162			PL_diehook = 0;
163
164			PUSHSTACKi (PERLSI_SIGNAL);
165
166			PUSHMARK (SP);
167			XPUSHs (sv_2mortal (newSViv (value)));
168			PUTBACK;
169			call_sv (async->cb, G_VOID \| G_DISCARD \| G_EVAL);
170
171			if (SvTRUE (ERRSV))
172			{
173			SPAGAIN;
174
175			PUSHMARK (SP);
176			PUTBACK;
177			call_sv (get_sv ("Async::Interrupt::DIED", 1), G_VOID \| G_DISCARD \| G_EVAL \| G_KEEPERR);
178
179			sv_setpvn (ERRSV, "", 0);
180			}
181
182			if (saveerr)
183			sv_setsv (ERRSV, saveerr);
184	root	1.1
185	root	1.2	{
186			SV *oldhook = PL_diehook;
187			PL_diehook = savedie;
188			SvREFCNT_dec (oldhook);
189			}
190
191			POPSTACK;
192	root	1.1	}
193
194	root	1.2	errno = old_errno;
195	root	1.1	}
196
197			static void
198	root	1.2	handle_asyncs (void)
199	root	1.1	{
200	root	1.2	int i;
201
202	root	1.1	async_pending = 0;
203	root	1.2
204			for (i = AvFILLp (asyncs); i >= 0; --i)
205			{
206	root	1.6	async_t *async = SvASYNC_nrv (AvARRAY (asyncs)[i]);
207	root	1.2
208			if (async->pending && !async->blocked)
209			handle_async (async);
210			}
211	root	1.1	}
212
213	root	1.5	#if HAS_SA_SIGINFO
214	root	1.1	static Signal_t async_sighandler (int signum, siginfo_t si, void sarg)
215			{
216			if (signum == 9)
217	root	1.2	handle_asyncs ();
218	root	1.1	else
219			old_sighandler (signum, si, sarg);
220			}
221			#else
222	root	1.3	static Signal_t async_sighandler (int signum)
223	root	1.1	{
224			if (signum == 9)
225	root	1.3	handle_asyncs ();
226	root	1.1	else
227			old_sighandler (signum);
228			}
229			#endif
230
231	root	1.4	static void
232	root	1.6	async_sigsend (int signum)
233			{
234			async_signal (sig_async [signum], 0);
235			}
236
237	root	1.7	#define block(async) ++(async)->blocked
238
239	root	1.6	static void
240	root	1.7	unblock (async_t *async)
241	root	1.4	{
242			--async->blocked;
243			if (async->pending && !async->blocked)
244			handle_async (async);
245	root	1.7	}
246	root	1.4
247	root	1.7	static void
248			scope_block_cb (pTHX_ void *async_sv)
249			{
250			async_t async = SvASYNC_nrv ((SV )async_sv);
251			unblock (async);
252	root	1.4	SvREFCNT_dec (async_sv);
253			}
254	root	1.1
255			MODULE = Async::Interrupt PACKAGE = Async::Interrupt
256
257			BOOT:
258			old_sighandler = PL_sighandlerp;
259			PL_sighandlerp = async_sighandler;
260			sig_pending = &PL_sig_pending;
261			psig_pend = PL_psig_pend;
262			asyncs = newAV ();
263	root	1.4	CvNODEBUG_on (get_cv ("Async::Interrupt::scope_block", 0)); /* otherwise calling scope can be the debugger */
264	root	1.1
265	root	1.3	PROTOTYPES: DISABLE
266
267	root	1.6	void
268			_alloc (SV cb, void c_cb, void c_arg, SV fh_r, SV fh_w, SV signl)
269			PPCODE:
270	root	1.1	{
271	root	1.5	SV *cv = SvOK (cb) ? SvREFCNT_inc (get_cb (cb)) : 0;
272	root	1.2	int fd_r = SvOK (fh_r) ? extract_fd (fh_r, 0) : -1;
273			int fd_w = SvOK (fh_w) ? extract_fd (fh_w, 1) : -1;
274	root	1.6	async_t *async;
275	root	1.1
276	root	1.6	Newz (0, async, 1, async_t);
277	root	1.1
278	root	1.6	XPUSHs (sv_2mortal (newSViv (PTR2IV (async))));
279			av_push (asyncs, TOPs);
280	root	1.2
281	root	1.6	async->fh_r = fd_r >= 0 ? newSVsv (fh_r) : 0; async->fd_r = fd_r;
282			async->fh_w = fd_w >= 0 ? newSVsv (fh_w) : 0; async->fd_w = fd_w;
283			async->fd_wlen = 1;
284			async->fd_enable = 1;
285			async->cb = cv;
286			async->c_cb = c_cb;
287			async->c_arg = c_arg;
288			SvGETMAGIC (signl);
289			async->signum = SvOK (signl) ? sv_signum (signl) : 0;
290
291			if (async->signum)
292			{
293			if (async->signum < 0)
294			croak ("Async::Interrupt::new got passed illegal signal name or number: %s", SvPV_nolen (signl));
295
296			sig_async [async->signum] = async;
297			#if _WIN32
298			signal (async->signum, async_sigsend);
299			#else
300			{
301			struct sigaction sa = { };
302			sa.sa_handler = async_sigsend;
303			sigfillset (&sa.sa_mask);
304			sigaction (async->signum, &sa, 0);
305			}
306			#endif
307			}
308	root	1.1	}
309
310			void
311	root	1.6	signal_func (async_t *async)
312	root	1.1	PPCODE:
313			EXTEND (SP, 2);
314			PUSHs (sv_2mortal (newSViv (PTR2IV (async_signal))));
315	root	1.6	PUSHs (sv_2mortal (newSViv (PTR2IV (async))));
316	root	1.1
317			void
318	root	1.6	signal (async_t *async, int value = 0)
319	root	1.1	CODE:
320	root	1.6	async_signal (async, value);
321	root	1.2
322			void
323	root	1.6	block (async_t *async)
324	root	1.2	CODE:
325	root	1.7	block (async);
326	root	1.2
327			void
328	root	1.6	unblock (async_t *async)
329	root	1.2	CODE:
330	root	1.7	unblock (async);
331	root	1.1
332			void
333	root	1.4	scope_block (SV *self)
334			CODE:
335			{
336			SV *async_sv = SvRV (self);
337	root	1.6	async_t *async = SvASYNC_nrv (async_sv);
338	root	1.7	block (async);
339	root	1.4
340			LEAVE; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
341			SAVEDESTRUCTOR_X (scope_block_cb, (void *)SvREFCNT_inc (async_sv));
342			ENTER; /* unfortunately, perl sandwiches XS calls into ENTER/LEAVE */
343			}
344
345			void
346	root	1.6	pipe_enable (async_t *async)
347			ALIAS:
348			pipe_enable = 1
349			pipe_disable = 0
350			CODE:
351			async->fd_enable = ix;
352
353			void
354	root	1.1	DESTROY (SV *self)
355			CODE:
356			{
357			int i;
358			SV *async_sv = SvRV (self);
359	root	1.6	async_t *async = SvASYNC_nrv (async_sv);
360	root	1.1
361	root	1.2	for (i = AvFILLp (asyncs); i >= 0; --i)
362	root	1.1	if (AvARRAY (asyncs)[i] == async_sv)
363			{
364			if (i < AvFILLp (asyncs))
365	root	1.3	AvARRAY (asyncs)[i] = AvARRAY (asyncs)[AvFILLp (asyncs)];
366	root	1.1
367			assert (av_pop (asyncs) == async_sv);
368			goto found;
369			}
370
371			if (!PL_dirty)
372	root	1.2	warn ("Async::Interrupt::DESTROY could not find async object in list of asyncs, please report");
373	root	1.1
374			found:
375	root	1.6
376			if (async->signum)
377			{
378			#if _WIN32
379			signal (async->signum, SIG_DFL);
380			#else
381			{
382			struct sigaction sa = { };
383			sa.sa_handler = SIG_DFL;
384			sigaction (async->signum, &sa, 0);
385			}
386			#endif
387			}
388
389	root	1.2	SvREFCNT_dec (async->fh_r);
390			SvREFCNT_dec (async->fh_w);
391	root	1.1	SvREFCNT_dec (async->cb);
392
393			Safefree (async);
394			}
395