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 (14 years, 11 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 *
#	Content
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	#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	/*****************************************************************************/
26	/* support stuff, copied from EV.xs mostly */
27
28	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	#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
84	typedef struct {
85	SV *cb;
86	void (c_cb)(pTHX_ void c_arg, int value);
87	void *c_arg;
88	SV fh_r, fh_w;
89	int blocked;
90	int signum;
91
92	int fd_r, fd_w;
93	int fd_wlen;
94	atomic_t fd_enable;
95	atomic_t value;
96	atomic_t pending;
97	} 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
105	/* the main workhorse to signal */
106	static void
107	async_signal (void *signal_arg, int value)
108	{
109	static char pipedata [8];
110
111	async_t async = (async_t )signal_arg;
112	int pending = async->pending;
113
114	async->value = value;
115	async->pending = 1;
116	async_pending = 1;
117	psig_pend [9] = 1;
118	*sig_pending = 1;
119
120	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	}
125
126	static void
127	handle_async (async_t *async)
128	{
129	int old_errno = errno;
130	int value = async->value;
131
132	async->pending = 0;
133
134	/* drain pipe */
135	if (async->fd_r >= 0 && async->fd_enable)
136	{
137	char dummy [9]; /* 9 is enough for eventfd and normal pipes */
138
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
179	{
180	SV *oldhook = PL_diehook;
181	PL_diehook = savedie;
182	SvREFCNT_dec (oldhook);
183	}
184
185	POPSTACK;
186	}
187
188	errno = old_errno;
189	}
190
191	static void
192	handle_asyncs (void)
193	{
194	int i;
195
196	async_pending = 0;
197
198	for (i = AvFILLp (asyncs); i >= 0; --i)
199	{
200	async_t *async = SvASYNC_nrv (AvARRAY (asyncs)[i]);
201
202	if (async->pending && !async->blocked)
203	handle_async (async);
204	}
205	}
206
207	#if HAS_SA_SIGINFO
208	static Signal_t async_sighandler (int signum, siginfo_t si, void sarg)
209	{
210	if (signum == 9)
211	handle_asyncs ();
212	else
213	old_sighandler (signum, si, sarg);
214	}
215	#else
216	static Signal_t async_sighandler (int signum)
217	{
218	if (signum == 9)
219	handle_asyncs ();
220	else
221	old_sighandler (signum);
222	}
223	#endif
224
225	static void
226	async_sigsend (int signum)
227	{
228	async_signal (sig_async [signum], 0);
229	}
230
231	static void
232	scope_block_cb (pTHX_ void *async_sv)
233	{
234	async_t async = SvASYNC_nrv ((SV )async_sv);
235
236	--async->blocked;
237	if (async->pending && !async->blocked)
238	handle_async (async);
239
240	SvREFCNT_dec (async_sv);
241	}
242
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	CvNODEBUG_on (get_cv ("Async::Interrupt::scope_block", 0)); /* otherwise calling scope can be the debugger */
252
253	PROTOTYPES: DISABLE
254
255	void
256	_alloc (SV cb, void c_cb, void c_arg, SV fh_r, SV fh_w, SV signl)
257	PPCODE:
258	{
259	SV *cv = SvOK (cb) ? SvREFCNT_inc (get_cb (cb)) : 0;
260	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	async_t *async;
263
264	Newz (0, async, 1, async_t);
265
266	XPUSHs (sv_2mortal (newSViv (PTR2IV (async))));
267	av_push (asyncs, TOPs);
268
269	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	}
297
298	void
299	signal_func (async_t *async)
300	PPCODE:
301	EXTEND (SP, 2);
302	PUSHs (sv_2mortal (newSViv (PTR2IV (async_signal))));
303	PUSHs (sv_2mortal (newSViv (PTR2IV (async))));
304
305	void
306	signal (async_t *async, int value = 0)
307	CODE:
308	async_signal (async, value);
309
310	void
311	block (async_t *async)
312	CODE:
313	++async->blocked;
314
315	void
316	unblock (async_t *async)
317	CODE:
318	--async->blocked;
319	if (async->pending && !async->blocked)
320	handle_async (async);
321
322	void
323	scope_block (SV *self)
324	CODE:
325	{
326	SV *async_sv = SvRV (self);
327	async_t *async = SvASYNC_nrv (async_sv);
328	++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	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	DESTROY (SV *self)
345	CODE:
346	{
347	int i;
348	SV *async_sv = SvRV (self);
349	async_t *async = SvASYNC_nrv (async_sv);
350
351	for (i = AvFILLp (asyncs); i >= 0; --i)
352	if (AvARRAY (asyncs)[i] == async_sv)
353	{
354	if (i < AvFILLp (asyncs))
355	AvARRAY (asyncs)[i] = AvARRAY (asyncs)[AvFILLp (asyncs)];
356
357	assert (av_pop (asyncs) == async_sv);
358	goto found;
359	}
360
361	if (!PL_dirty)
362	warn ("Async::Interrupt::DESTROY could not find async object in list of asyncs, please report");
363
364	found:
365
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	SvREFCNT_dec (async->fh_r);
380	SvREFCNT_dec (async->fh_w);
381	SvREFCNT_dec (async->cb);
382
383	Safefree (async);
384	}
385