On Fri, 2012-12-07 at 18:45 +0100, Svante Signell wrote:
> On Fri, 2012-12-07 at 17:35 +0100, Samuel Thibault wrote:
> > Svante Signell, le Fri 07 Dec 2012 17:13:00 +0100, a écrit :
> > > In the works of rewriting hurdselect.c I have some question on how to
> > > write patches. The changed code contains three parts:
> > > 1) Introducing three cases: DELAY, POLL, and SELECT
> >
> > Why three cases? Isn't there a lot of common code between poll and
> > select?
>
> Unfortunately the differences are too large to have them in the same
> code path, without loosing the overview. Additionally, the pure delay
> code is much faster than today's as reported in
> http://lists.gnu.org/archive/html/bug-hurd/2012-11/msg00000.html
As promised, attached is the first patch to split hurdselect.c code into
three cases: DELAY, POLL and SELECT, doing the first two parts as
promised in an earlier mail:
1) Introducing three cases: DELAY, POLL, and SELECT
2) Removing the unneeded code for each case statement
It does _not_ include any poll code updates yet, that will be in part 3,
i.e. the step 2 patch:
3) Rewriting the poll case to be compliant with POSIX 2001.
Attached is both a diff with the new code to the debian patched
hurdselect.c and the complete hurdselect_step1.c.
Additional notes:
- The one FD patch by Richard is included, applied to both the POLL and
SELECT cases. Now the timeouts are correct (measured too).
- The pure delay case is much faster now, making it necessary to
introduce a delay of 1 msec when the timeout parameter is set to zero.
Otherwise the file descriptors will not be ready, and the test fails.
For test code see the link above.
- The flat delay of 1 msec is also needed in order to get ntpdate
working! The old implementation does also work now, but as mentioned
above, it does not with the new code. (and according to the debian
patch: vim)
- The union and some constant definitions have been moved to before the
three cases: DELAY, POLL and SELECT.
- Comments for the sigmask stuff, needed for ppoll and pselect has been
added. These functions are not yet implemented.
- Notes haver been added to where the code has a bug for the POLL case.
The updated POLL code will resolve mot of these bugs.
- Hopefully the code is more readable now, without causing regressions.
- Of course there might be indentation differences, not so clear
comments, etc, but this is the first version of the rewrite!
Comments welcomed, when hopefully accepted (after reviews) the POLL
update will follow. Further test code both for the DELAY, POLL and
SELECT cases is available if of interest.
Thanks,
Svante
--- hurdselect_orig.c 2012-10-21 22:55:26.000000000 +0200
+++ hurdselect_step1.c 2012-12-12 19:29:26.000000000 +0100
@@ -37,6 +37,13 @@
each of READFDS, WRITEFDS, EXCEPTFDS that is nonnull. If TIMEOUT is not
NULL, time out after waiting the interval specified therein. Returns
the number of ready descriptors, or -1 for errors. */
+
+enum {
+ DELAY = -1,
+ SELECT = 0,
+ POLL = 1
+} ispoll;
+
int
_hurd_select (int nfds,
struct pollfd *pollfds,
@@ -68,6 +75,52 @@ _hurd_select (int nfds,
assert (sizeof (union typeword) == sizeof (mach_msg_type_t));
assert (sizeof (uint32_t) == sizeof (mach_msg_type_t));
+
+ union
+ {
+ mach_msg_header_t head;
+#ifdef MACH_MSG_TRAILER_MINIMUM_SIZE
+ struct
+ {
+ mach_msg_header_t head;
+ NDR_record_t ndr;
+ error_t err;
+ } error;
+ struct
+ {
+ mach_msg_header_t head;
+ NDR_record_t ndr;
+ error_t err;
+ int result;
+ mach_msg_trailer_t trailer;
+ } success;
+#else
+ struct
+ {
+ mach_msg_header_t head;
+ union typeword err_type;
+ error_t err;
+ } error;
+ struct
+ {
+ mach_msg_header_t head;
+ union typeword err_type;
+ error_t err;
+ union typeword result_type;
+ int result;
+ } success;
+#endif
+ } msg;
+ mach_msg_option_t options = (timeout == NULL ? 0 : MACH_RCV_TIMEOUT);
+ error_t msgerr;
+#define IO_SELECT_REPLY_MSGID (21012 + 100) /* XXX */
+#ifdef MACH_MSG_TYPE_BIT
+ const union typeword inttype =
+ { type:
+ { MACH_MSG_TYPE_INTEGER_T, sizeof (integer_t) * 8, 1, 1, 0, 0 }
+ };
+#endif
+
if (nfds < 0 || nfds > FD_SETSIZE)
{
errno = EINVAL;
@@ -84,15 +137,114 @@ _hurd_select (int nfds,
to = (timeout->tv_sec * 1000 +
(timeout->tv_nsec + 999999) / 1000000);
- if (strcmp(program_invocation_short_name, "vi") && strcmp(program_invocation_short_name, "vim") && strcmp(program_invocation_short_name, "vimdiff") && !to)
- to = 1;
}
+ /* XXX: A timeout of 0 returns immediately, even if no file
+ descriptors are ready. This is correct according to POSIX.1-2001.
+ As many programs rely on file descriptors being ready for a
+ timeout of zero use 1 msec as the minimum delay */
+ /* FIXME: replace with something better */
+#if 1
+ if (to == 0)
+ to = 1;
+#endif
+ /* FIXME: sigmask is only used for ppoll and pselect: not yet implemented */
if (sigmask && __sigprocmask (SIG_SETMASK, sigmask, &oset))
return -1;
- if (pollfds)
+ if (nfds == 0)
+ ispoll = DELAY;
+ else if (pollfds)
+ ispoll = POLL;
+ else
+ ispoll = SELECT;
+
+ if (nfds > _hurd_dtablesize)
+ nfds = _hurd_dtablesize;
+
+ switch (ispoll)
{
+ case DELAY:
+ /* We are just a pure timeout. */
+ portset = __mach_reply_port ();
+
+ err = 0;
+
+ /* Now wait for reply messages. */
+ if (!err)
+ {
+ /* Now wait for io_select_reply messages on PORT,
+ timing out as appropriate. */
+ while ((msgerr = __mach_msg (&msg.head,
+ MACH_RCV_MSG | options,
+ 0, sizeof msg, portset, to,
+ MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
+ {
+ /* We got a message. Decode it. */
+ if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
+ msg.head.msgh_size >= sizeof msg.error &&
+ !(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
+#ifdef MACH_MSG_TYPE_BIT
+ msg.error.err_type.word == inttype.word
+#endif
+ )
+ {
+ /* This is a properly formatted message so far.
+ See if it is a success or a failure. */
+ if (msg.error.err == EINTR &&
+ msg.head.msgh_size == sizeof msg.error)
+ {
+ /* EINTR response; poll for further responses
+ and then return quickly. */
+ err = EINTR;
+ goto exit;
+ }
+ if (msg.error.err ||
+ msg.head.msgh_size != sizeof msg.success ||
+#ifdef MACH_MSG_TYPE_BIT
+ msg.success.result_type.word != inttype.word ||
+#endif
+ (msg.success.result & SELECT_ALL) == 0)
+ {
+ /* Error or bogus reply. Simulate readiness. */
+ __mach_msg_destroy (&msg.head);
+ msg.success.result = SELECT_ALL;
+ }
+ } /* end ) { */
+
+ if (msg.head.msgh_remote_port != MACH_PORT_NULL)
+ __mach_port_deallocate (__mach_task_self (),
+ msg.head.msgh_remote_port);
+ } /* while */
+
+ exit:
+ if (err == MACH_RCV_TIMED_OUT)
+ /* This is the normal value for ERR. We might have timed
+ out and read no messages. Otherwise, after receiving
+ the first message, we poll for more messages. We
+ receive with a timeout of 0 to effect a poll, so ERR is
+ MACH_RCV_TIMED_OUT when the poll finds no message
+ waiting. */
+ err = 0;
+
+ } /* if(!err) */
+
+ /* Destroy PORTSET, but only if it's not actually the reply
+ port for a single descriptor (in which case it's
+ destroyed in the previous loop; not doing it here is just
+ a bit more efficient). */
+ __mach_port_destroy (__mach_task_self (), portset);
+
+ if (err)
+ {
+ errno = err;
+ return -1;
+ }
+ else
+ return 0;
+ break;
+
+ case POLL:
/* Collect interesting descriptors from the user's `pollfd' array.
We do a first pass that reads the user's array before taking
any locks. The second pass then only touches our own stack,
@@ -132,6 +284,7 @@ _hurd_select (int nfds,
}
/* If one descriptor is bogus, we fail completely. */
+ /* This is a bug in the current implementation, see POSIX 2001 */
while (i-- > 0)
if (d[i].type != 0)
_hurd_port_free (&d[i].cell->port,
@@ -142,21 +295,212 @@ _hurd_select (int nfds,
__mutex_unlock (&_hurd_dtable_lock);
HURD_CRITICAL_END;
+ /* This is a bug in the current implementation, see POSIX 2001 */
if (i < nfds)
{
+ /* FIXME: Only for ppoll */
if (sigmask)
__sigprocmask (SIG_SETMASK, &oset, NULL);
errno = EBADF;
return -1;
}
+ firstfd = 0;
lastfd = i - 1;
- firstfd = i == 0 ? lastfd : 0;
- }
- else
- {
+ err = 0;
+ got = 0;
+
+ /* Send them all io_select request messages. */
+ portset = MACH_PORT_NULL;
+
+ for (i = firstfd; i <= lastfd; ++i)
+ if (d[i].type)
+ {
+ int type = d[i].type;
+ d[i].reply_port = __mach_reply_port ();
+ err = __io_select (d[i].io_port, d[i].reply_port,
+ /* Poll only if there's a single descriptor. */
+ (firstfd == lastfd) ? to : 0,
+ &type);
+ switch (err)
+ {
+ case MACH_RCV_TIMED_OUT:
+ /* No immediate response. This is normal. */
+ err = 0;
+ if (firstfd == lastfd)
+ /* When there's a single descriptor, we don't need a
+ portset, so just pretend we have one, but really
+ use the single reply port. */
+ portset = d[i].reply_port;
+ else if (got == 0)
+ /* We've got multiple reply ports, so we need a port set to
+ multiplex them. */
+ {
+ /* We will wait again for a reply later. */
+ if (portset == MACH_PORT_NULL)
+ /* Create the portset to receive all the replies on. */
+ err = __mach_port_allocate (__mach_task_self (),
+ MACH_PORT_RIGHT_PORT_SET,
+ &portset);
+ if (! err)
+ /* Put this reply port in the port set. */
+ __mach_port_move_member (__mach_task_self (),
+ d[i].reply_port, portset);
+ }
+ break;
+
+ default:
+ /* No other error should happen. Callers of select
+ don't expect to see errors, so we simulate
+ readiness of the erring object and the next call
+ hopefully will get the error again. */
+ type = SELECT_ALL;
+ /* FALLTHROUGH */
+
+ case 0:
+ /* We got an answer. */
+ if ((type & SELECT_ALL) == 0)
+ /* Bogus answer; treat like an error, as a fake positive. */
+ type = SELECT_ALL;
+
+ /* This port is already ready already. */
+ d[i].type &= type;
+ d[i].type |= SELECT_RETURNED;
+ ++got;
+ break;
+ }
+ _hurd_port_free (&d[i].cell->port, &d[i].ulink, d[i].io_port);
+ }
+
+ /* Now wait for reply messages. */
+ if (!err && got == 0 && (firstfd != lastfd))
+ {
+ /* Now wait for io_select_reply messages on PORT,
+ timing out as appropriate. */
+
+ while ((msgerr = __mach_msg (&msg.head,
+ MACH_RCV_MSG | options,
+ 0, sizeof msg, portset, to,
+ MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
+ {
+ /* We got a message. Decode it. */
+ if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
+ msg.head.msgh_size >= sizeof msg.error &&
+ !(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
+#ifdef MACH_MSG_TYPE_BIT
+ msg.error.err_type.word == inttype.word
+#endif
+ )
+ {
+ /* This is a properly formatted message so far.
+ See if it is a success or a failure. */
+ if (msg.error.err == EINTR &&
+ msg.head.msgh_size == sizeof msg.error)
+ {
+ /* EINTR response; poll for further responses
+ and then return quickly. */
+ err = EINTR;
+ goto poll;
+ }
+ if (msg.error.err ||
+ msg.head.msgh_size != sizeof msg.success ||
+#ifdef MACH_MSG_TYPE_BIT
+ msg.success.result_type.word != inttype.word ||
+#endif
+ (msg.success.result & SELECT_ALL) == 0)
+ {
+ /* Error or bogus reply. Simulate readiness. */
+ __mach_msg_destroy (&msg.head);
+ msg.success.result = SELECT_ALL;
+ }
+
+ /* Look up the respondent's reply port and record its
+ readiness. */
+ int had = got;
+ for (i = firstfd; i <= lastfd; ++i)
+ if (d[i].type
+ && d[i].reply_port == msg.head.msgh_local_port)
+ {
+ d[i].type &= msg.success.result;
+ d[i].type |= SELECT_RETURNED;
+ ++got;
+ }
+ assert (got > had);
+ }
+
+ if (msg.head.msgh_remote_port != MACH_PORT_NULL)
+ __mach_port_deallocate (__mach_task_self (),
+ msg.head.msgh_remote_port);
+
+ if (got)
+ poll:
+ {
+ /* Poll for another message. */
+ to = 0;
+ options |= MACH_RCV_TIMEOUT;
+ }
+ }
+
+ if (err == MACH_RCV_TIMED_OUT)
+ /* This is the normal value for ERR. We might have timed out and
+ read no messages. Otherwise, after receiving the first message,
+ we poll for more messages. We receive with a timeout of 0 to
+ effect a poll, so ERR is MACH_RCV_TIMED_OUT when the poll finds no
+ message waiting. */
+ err = 0;
+
+ if (got)
+ /* At least one descriptor is known to be ready now, so we will
+ return success. */
+ err = 0;
+ }
+
+ for (i = firstfd; i <= lastfd; ++i)
+ if (d[i].type)
+ __mach_port_destroy (__mach_task_self (), d[i].reply_port);
+ if ((firstfd != lastfd) && (portset != MACH_PORT_NULL))
+ /* Destroy PORTSET, but only if it's not actually the reply
+ port for a single descriptor (in which case it's destroyed
+ in the previous loop; not doing it here is just a bit more
+ efficient). */
+ __mach_port_destroy (__mach_task_self (), portset);
+
+ if (err)
+ {
+ /* FIXME: Only for ppoll */
+ if (sigmask)
+ __sigprocmask (SIG_SETMASK, &oset, NULL);
+ return __hurd_fail (err);
+ }
+
+ /* Fill in the `revents' members of the user's array. */
+ for (i = 0; i < nfds; ++i)
+ {
+ int type = d[i].type;
+ int_fast16_t revents = 0;
+
+ if (type & SELECT_RETURNED)
+ {
+ if (type & SELECT_READ)
+ revents |= POLLIN;
+ if (type & SELECT_WRITE)
+ revents |= POLLOUT;
+ if (type & SELECT_URG)
+ revents |= POLLPRI;
+ }
+ pollfds[i].revents = revents;
+ }
+
+ /* FIXME: Only for ppoll */
+ if (sigmask && __sigprocmask (SIG_SETMASK, &oset, NULL))
+ return -1;
+
+ return got;
+ break;
+
+ case SELECT:
/* Collect interested descriptors from the user's fd_set arguments.
- Use local copies so we can't crash from user bogosity. */
+ Use local copies so we can't crash from user bogosity. */
if (readfds == NULL)
FD_ZERO (&rfds);
@@ -174,11 +518,7 @@ _hurd_select (int nfds,
HURD_CRITICAL_BEGIN;
__mutex_lock (&_hurd_dtable_lock);
- if (nfds > _hurd_dtablesize)
- nfds = _hurd_dtablesize;
-
- /* Collect the ports for interesting FDs. */
- firstfd = lastfd = -1;
+ /* Collect the ports for interesting FDs. */
for (i = 0; i < nfds; ++i)
{
int type = 0;
@@ -203,8 +543,6 @@ _hurd_select (int nfds,
break;
}
lastfd = i;
- if (firstfd == -1)
- firstfd = i;
}
}
@@ -213,25 +551,17 @@ _hurd_select (int nfds,
if (i < nfds)
{
+ /* FIXME: Only for pselect */
if (sigmask)
__sigprocmask (SIG_SETMASK, &oset, NULL);
errno = EBADF;
return -1;
}
- }
-
-
- err = 0;
- got = 0;
-
- /* Send them all io_select request messages. */
+ firstfd = 0;
+ err = 0;
+ got = 0;
- if (firstfd == -1)
- /* But not if there were no ports to deal with at all.
- We are just a pure timeout. */
- portset = __mach_reply_port ();
- else
- {
+ /* Send them all io_select request messages. */
portset = MACH_PORT_NULL;
for (i = firstfd; i <= lastfd; ++i)
@@ -284,7 +614,7 @@ _hurd_select (int nfds,
/* Bogus answer; treat like an error, as a fake positive. */
type = SELECT_ALL;
- /* This port is already ready already. */
+ /* This port is already ready already. */
d[i].type &= type;
d[i].type |= SELECT_RETURNED;
++got;
@@ -292,99 +622,51 @@ _hurd_select (int nfds,
}
_hurd_port_free (&d[i].cell->port, &d[i].ulink, d[i].io_port);
}
- }
-
- /* Now wait for reply messages. */
- if (!err && got == 0)
- {
- /* Now wait for io_select_reply messages on PORT,
- timing out as appropriate. */
- union
+ /* Now wait for reply messages. */
+ if (!err && got == 0 && (firstfd != lastfd))
{
- mach_msg_header_t head;
-#ifdef MACH_MSG_TRAILER_MINIMUM_SIZE
- struct
+ /* Now wait for io_select_reply messages on PORT,
+ timing out as appropriate. */
+ while ((msgerr = __mach_msg (&msg.head,
+ MACH_RCV_MSG | options,
+ 0, sizeof msg, portset, to,
+ MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
{
- mach_msg_header_t head;
- NDR_record_t ndr;
- error_t err;
- } error;
- struct
- {
- mach_msg_header_t head;
- NDR_record_t ndr;
- error_t err;
- int result;
- mach_msg_trailer_t trailer;
- } success;
-#else
- struct
- {
- mach_msg_header_t head;
- union typeword err_type;
- error_t err;
- } error;
- struct
- {
- mach_msg_header_t head;
- union typeword err_type;
- error_t err;
- union typeword result_type;
- int result;
- } success;
-#endif
- } msg;
- mach_msg_option_t options = (timeout == NULL ? 0 : MACH_RCV_TIMEOUT);
- error_t msgerr;
- while ((msgerr = __mach_msg (&msg.head,
- MACH_RCV_MSG | options,
- 0, sizeof msg, portset, to,
- MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
- {
- /* We got a message. Decode it. */
-#define IO_SELECT_REPLY_MSGID (21012 + 100) /* XXX */
-#ifdef MACH_MSG_TYPE_BIT
- const union typeword inttype =
- { type:
- { MACH_MSG_TYPE_INTEGER_T, sizeof (integer_t) * 8, 1, 1, 0, 0 }
- };
-#endif
- if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
- msg.head.msgh_size >= sizeof msg.error &&
- !(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
+ /* We got a message. Decode it. */
+ if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
+ msg.head.msgh_size >= sizeof msg.error &&
+ !(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
#ifdef MACH_MSG_TYPE_BIT
- msg.error.err_type.word == inttype.word
+ msg.error.err_type.word == inttype.word
#endif
- )
- {
- /* This is a properly formatted message so far.
- See if it is a success or a failure. */
- if (msg.error.err == EINTR &&
- msg.head.msgh_size == sizeof msg.error)
+ )
{
- /* EINTR response; poll for further responses
- and then return quickly. */
- err = EINTR;
- goto poll;
- }
- if (msg.error.err ||
- msg.head.msgh_size != sizeof msg.success ||
+ /* This is a properly formatted message so far.
+ See if it is a success or a failure. */
+ if (msg.error.err == EINTR &&
+ msg.head.msgh_size == sizeof msg.error)
+ {
+ /* EINTR response; poll for further responses
+ and then return quickly. */
+ err = EINTR;
+ goto poll2;
+ }
+ if (msg.error.err ||
+ msg.head.msgh_size != sizeof msg.success ||
#ifdef MACH_MSG_TYPE_BIT
- msg.success.result_type.word != inttype.word ||
+ msg.success.result_type.word != inttype.word ||
#endif
- (msg.success.result & SELECT_ALL) == 0)
- {
- /* Error or bogus reply. Simulate readiness. */
- __mach_msg_destroy (&msg.head);
- msg.success.result = SELECT_ALL;
- }
-
- /* Look up the respondent's reply port and record its
- readiness. */
- {
- int had = got;
- if (firstfd != -1)
+ (msg.success.result & SELECT_ALL) == 0)
+ {
+ /* Error or bogus reply. Simulate readiness. */
+ __mach_msg_destroy (&msg.head);
+ msg.success.result = SELECT_ALL;
+ }
+
+ /* Look up the respondent's reply port and record its
+ readiness. */
+ int had = got;
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type
&& d[i].reply_port == msg.head.msgh_local_port)
@@ -393,106 +675,90 @@ _hurd_select (int nfds,
d[i].type |= SELECT_RETURNED;
++got;
}
- assert (got > had);
- }
- }
+ assert (got > had);
+ }
- if (msg.head.msgh_remote_port != MACH_PORT_NULL)
- __mach_port_deallocate (__mach_task_self (),
- msg.head.msgh_remote_port);
+ if (msg.head.msgh_remote_port != MACH_PORT_NULL)
+ __mach_port_deallocate (__mach_task_self (),
+ msg.head.msgh_remote_port);
- if (got)
- poll:
- {
- /* Poll for another message. */
- to = 0;
- options |= MACH_RCV_TIMEOUT;
+ if (got)
+ poll2:
+ {
+ /* Poll for another message. */
+ to = 0;
+ options |= MACH_RCV_TIMEOUT;
+ }
}
- }
- if (err == MACH_RCV_TIMED_OUT)
- /* This is the normal value for ERR. We might have timed out and
- read no messages. Otherwise, after receiving the first message,
- we poll for more messages. We receive with a timeout of 0 to
- effect a poll, so ERR is MACH_RCV_TIMED_OUT when the poll finds no
- message waiting. */
- err = 0;
-
- if (got)
- /* At least one descriptor is known to be ready now, so we will
- return success. */
- err = 0;
- }
+ if (err == MACH_RCV_TIMED_OUT)
+ /* This is the normal value for ERR. We might have timed out and
+ read no messages. Otherwise, after receiving the first message,
+ we poll for more messages. We receive with a timeout of 0 to
+ effect a poll, so ERR is MACH_RCV_TIMED_OUT when the poll finds no
+ message waiting. */
+ err = 0;
- if (firstfd != -1)
- for (i = firstfd; i <= lastfd; ++i)
- if (d[i].type)
- __mach_port_destroy (__mach_task_self (), d[i].reply_port);
- if (firstfd == -1 || (firstfd != lastfd && portset != MACH_PORT_NULL))
- /* Destroy PORTSET, but only if it's not actually the reply port for a
- single descriptor (in which case it's destroyed in the previous loop;
- not doing it here is just a bit more efficient). */
- __mach_port_destroy (__mach_task_self (), portset);
-
- if (err)
- {
- if (sigmask)
- __sigprocmask (SIG_SETMASK, &oset, NULL);
- return __hurd_fail (err);
- }
-
- if (pollfds)
- /* Fill in the `revents' members of the user's array. */
- for (i = 0; i < nfds; ++i)
- {
- int type = d[i].type;
- int_fast16_t revents = 0;
+ if (got)
+ /* At least one descriptor is known to be ready now, so we will
+ return success. */
+ err = 0;
+ }
- if (type & SELECT_RETURNED)
- {
- if (type & SELECT_READ)
- revents |= POLLIN;
- if (type & SELECT_WRITE)
- revents |= POLLOUT;
- if (type & SELECT_URG)
- revents |= POLLPRI;
- }
+ for (i = firstfd; i <= lastfd; ++i)
+ if (d[i].type)
+ __mach_port_destroy (__mach_task_self (), d[i].reply_port);
+ if ((firstfd != lastfd) && (portset != MACH_PORT_NULL))
+ /* Destroy PORTSET, but only if it's not actually the reply port for a
+ single descriptor (in which case it's destroyed in the previous loop;
+ not doing it here is just a bit more efficient). */
+ __mach_port_destroy (__mach_task_self (), portset);
+
+ if (err)
+ {
+ /* FIXME: Only for pselect */
+ if (sigmask)
+ __sigprocmask (SIG_SETMASK, &oset, NULL);
+ return __hurd_fail (err);
+ }
- pollfds[i].revents = revents;
- }
- else
- {
/* Below we recalculate GOT to include an increment for each operation
allowed on each fd. */
got = 0;
/* Set the user bitarrays. We only ever have to clear bits, as all
desired ones are initially set. */
- if (firstfd != -1)
- for (i = firstfd; i <= lastfd; ++i)
- {
- int type = d[i].type;
+ for (i = firstfd; i <= lastfd; ++i)
+ {
+ int type = d[i].type;
+
+ if ((type & SELECT_RETURNED) == 0)
+ type = 0;
+
+ if (type & SELECT_READ)
+ got++;
+ else if (readfds)
+ FD_CLR (i, readfds);
+ if (type & SELECT_WRITE)
+ got++;
+ else if (writefds)
+ FD_CLR (i, writefds);
+ if (type & SELECT_URG)
+ got++;
+ else if (exceptfds)
+ FD_CLR (i, exceptfds);
+ }
- if ((type & SELECT_RETURNED) == 0)
- type = 0;
+ /* FIXME: Only for pselect */
+ if (sigmask && __sigprocmask (SIG_SETMASK, &oset, NULL))
+ return -1;
- if (type & SELECT_READ)
- got++;
- else if (readfds)
- FD_CLR (i, readfds);
- if (type & SELECT_WRITE)
- got++;
- else if (writefds)
- FD_CLR (i, writefds);
- if (type & SELECT_URG)
- got++;
- else if (exceptfds)
- FD_CLR (i, exceptfds);
- }
- }
+ return got;
+ break;
- if (sigmask && __sigprocmask (SIG_SETMASK, &oset, NULL))
- return -1;
+ default:
+ errno = EINVAL;
+ return -1;
- return got;
+ } /* switch ispoll */
}
/* Guts of both `select' and `poll' for Hurd.
Copyright (C) 1991-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sys/types.h>
#include <sys/poll.h>
#include <hurd.h>
#include <hurd/fd.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdint.h>
/* All user select types. */
#define SELECT_ALL (SELECT_READ | SELECT_WRITE | SELECT_URG)
/* Used to record that a particular select rpc returned. Must be distinct
from SELECT_ALL (which better not have the high bit set). */
#define SELECT_RETURNED ((SELECT_ALL << 1) & ~SELECT_ALL)
/* Check the first NFDS descriptors either in POLLFDS (if nonnnull) or in
each of READFDS, WRITEFDS, EXCEPTFDS that is nonnull. If TIMEOUT is not
NULL, time out after waiting the interval specified therein. Returns
the number of ready descriptors, or -1 for errors. */
enum {
DELAY = -1,
SELECT = 0,
POLL = 1
} ispoll;
int
_hurd_select (int nfds,
struct pollfd *pollfds,
fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
const struct timespec *timeout, const sigset_t *sigmask)
{
int i;
mach_port_t portset;
int got;
error_t err;
fd_set rfds, wfds, xfds;
int firstfd, lastfd;
mach_msg_timeout_t to = 0;
struct
{
struct hurd_userlink ulink;
struct hurd_fd *cell;
mach_port_t io_port;
int type;
mach_port_t reply_port;
} d[nfds];
sigset_t oset;
union typeword /* Use this to avoid unkosher casts. */
{
mach_msg_type_t type;
uint32_t word;
};
assert (sizeof (union typeword) == sizeof (mach_msg_type_t));
assert (sizeof (uint32_t) == sizeof (mach_msg_type_t));
union
{
mach_msg_header_t head;
#ifdef MACH_MSG_TRAILER_MINIMUM_SIZE
struct
{
mach_msg_header_t head;
NDR_record_t ndr;
error_t err;
} error;
struct
{
mach_msg_header_t head;
NDR_record_t ndr;
error_t err;
int result;
mach_msg_trailer_t trailer;
} success;
#else
struct
{
mach_msg_header_t head;
union typeword err_type;
error_t err;
} error;
struct
{
mach_msg_header_t head;
union typeword err_type;
error_t err;
union typeword result_type;
int result;
} success;
#endif
} msg;
mach_msg_option_t options = (timeout == NULL ? 0 : MACH_RCV_TIMEOUT);
error_t msgerr;
#define IO_SELECT_REPLY_MSGID (21012 + 100) /* XXX */
#ifdef MACH_MSG_TYPE_BIT
const union typeword inttype =
{ type:
{ MACH_MSG_TYPE_INTEGER_T, sizeof (integer_t) * 8, 1, 1, 0, 0 }
};
#endif
if (nfds < 0 || nfds > FD_SETSIZE)
{
errno = EINVAL;
return -1;
}
if (timeout != NULL)
{
if (timeout->tv_sec < 0 || timeout->tv_nsec < 0)
{
errno = EINVAL;
return -1;
}
to = (timeout->tv_sec * 1000 +
(timeout->tv_nsec + 999999) / 1000000);
}
/* XXX: A timeout of 0 returns immediately, even if no file
descriptors are ready. This is correct according to POSIX.1-2001.
As many programs rely on file descriptors being ready for a
timeout of zero use 1 msec as the minimum delay */
/* FIXME: replace with something better */
#if 1
if (to == 0)
to = 1;
#endif
/* FIXME: sigmask is only used for ppoll and pselect: not yet implemented */
if (sigmask && __sigprocmask (SIG_SETMASK, sigmask, &oset))
return -1;
if (nfds == 0)
ispoll = DELAY;
else if (pollfds)
ispoll = POLL;
else
ispoll = SELECT;
if (nfds > _hurd_dtablesize)
nfds = _hurd_dtablesize;
switch (ispoll)
{
case DELAY:
/* We are just a pure timeout. */
portset = __mach_reply_port ();
err = 0;
/* Now wait for reply messages. */
if (!err)
{
/* Now wait for io_select_reply messages on PORT,
timing out as appropriate. */
while ((msgerr = __mach_msg (&msg.head,
MACH_RCV_MSG | options,
0, sizeof msg, portset, to,
MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
{
/* We got a message. Decode it. */
if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
msg.head.msgh_size >= sizeof msg.error &&
!(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
#ifdef MACH_MSG_TYPE_BIT
msg.error.err_type.word == inttype.word
#endif
)
{
/* This is a properly formatted message so far.
See if it is a success or a failure. */
if (msg.error.err == EINTR &&
msg.head.msgh_size == sizeof msg.error)
{
/* EINTR response; poll for further responses
and then return quickly. */
err = EINTR;
goto exit;
}
if (msg.error.err ||
msg.head.msgh_size != sizeof msg.success ||
#ifdef MACH_MSG_TYPE_BIT
msg.success.result_type.word != inttype.word ||
#endif
(msg.success.result & SELECT_ALL) == 0)
{
/* Error or bogus reply. Simulate readiness. */
__mach_msg_destroy (&msg.head);
msg.success.result = SELECT_ALL;
}
} /* end ) { */
if (msg.head.msgh_remote_port != MACH_PORT_NULL)
__mach_port_deallocate (__mach_task_self (),
msg.head.msgh_remote_port);
} /* while */
exit:
if (err == MACH_RCV_TIMED_OUT)
/* This is the normal value for ERR. We might have timed
out and read no messages. Otherwise, after receiving
the first message, we poll for more messages. We
receive with a timeout of 0 to effect a poll, so ERR is
MACH_RCV_TIMED_OUT when the poll finds no message
waiting. */
err = 0;
} /* if(!err) */
/* Destroy PORTSET, but only if it's not actually the reply
port for a single descriptor (in which case it's
destroyed in the previous loop; not doing it here is just
a bit more efficient). */
__mach_port_destroy (__mach_task_self (), portset);
if (err)
{
errno = err;
return -1;
}
else
return 0;
break;
case POLL:
/* Collect interesting descriptors from the user's `pollfd' array.
We do a first pass that reads the user's array before taking
any locks. The second pass then only touches our own stack,
and gets the port references. */
for (i = 0; i < nfds; ++i)
if (pollfds[i].fd >= 0)
{
int type = 0;
if (pollfds[i].events & POLLIN)
type |= SELECT_READ;
if (pollfds[i].events & POLLOUT)
type |= SELECT_WRITE;
if (pollfds[i].events & POLLPRI)
type |= SELECT_URG;
d[i].io_port = pollfds[i].fd;
d[i].type = type;
}
else
d[i].type = 0;
HURD_CRITICAL_BEGIN;
__mutex_lock (&_hurd_dtable_lock);
for (i = 0; i < nfds; ++i)
if (d[i].type != 0)
{
const int fd = (int) d[i].io_port;
if (fd < _hurd_dtablesize)
{
d[i].cell = _hurd_dtable[fd];
d[i].io_port = _hurd_port_get (&d[i].cell->port, &d[i].ulink);
if (d[i].io_port != MACH_PORT_NULL)
continue;
}
/* If one descriptor is bogus, we fail completely. */
/* This is a bug in the current implementation, see POSIX 2001 */
while (i-- > 0)
if (d[i].type != 0)
_hurd_port_free (&d[i].cell->port,
&d[i].ulink, d[i].io_port);
break;
}
__mutex_unlock (&_hurd_dtable_lock);
HURD_CRITICAL_END;
/* This is a bug in the current implementation, see POSIX 2001 */
if (i < nfds)
{
/* FIXME: Only for ppoll */
if (sigmask)
__sigprocmask (SIG_SETMASK, &oset, NULL);
errno = EBADF;
return -1;
}
firstfd = 0;
lastfd = i - 1;
err = 0;
got = 0;
/* Send them all io_select request messages. */
portset = MACH_PORT_NULL;
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type)
{
int type = d[i].type;
d[i].reply_port = __mach_reply_port ();
err = __io_select (d[i].io_port, d[i].reply_port,
/* Poll only if there's a single descriptor. */
(firstfd == lastfd) ? to : 0,
&type);
switch (err)
{
case MACH_RCV_TIMED_OUT:
/* No immediate response. This is normal. */
err = 0;
if (firstfd == lastfd)
/* When there's a single descriptor, we don't need a
portset, so just pretend we have one, but really
use the single reply port. */
portset = d[i].reply_port;
else if (got == 0)
/* We've got multiple reply ports, so we need a port set to
multiplex them. */
{
/* We will wait again for a reply later. */
if (portset == MACH_PORT_NULL)
/* Create the portset to receive all the replies on. */
err = __mach_port_allocate (__mach_task_self (),
MACH_PORT_RIGHT_PORT_SET,
&portset);
if (! err)
/* Put this reply port in the port set. */
__mach_port_move_member (__mach_task_self (),
d[i].reply_port, portset);
}
break;
default:
/* No other error should happen. Callers of select
don't expect to see errors, so we simulate
readiness of the erring object and the next call
hopefully will get the error again. */
type = SELECT_ALL;
/* FALLTHROUGH */
case 0:
/* We got an answer. */
if ((type & SELECT_ALL) == 0)
/* Bogus answer; treat like an error, as a fake positive. */
type = SELECT_ALL;
/* This port is already ready already. */
d[i].type &= type;
d[i].type |= SELECT_RETURNED;
++got;
break;
}
_hurd_port_free (&d[i].cell->port, &d[i].ulink, d[i].io_port);
}
/* Now wait for reply messages. */
if (!err && got == 0 && (firstfd != lastfd))
{
/* Now wait for io_select_reply messages on PORT,
timing out as appropriate. */
while ((msgerr = __mach_msg (&msg.head,
MACH_RCV_MSG | options,
0, sizeof msg, portset, to,
MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
{
/* We got a message. Decode it. */
if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
msg.head.msgh_size >= sizeof msg.error &&
!(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
#ifdef MACH_MSG_TYPE_BIT
msg.error.err_type.word == inttype.word
#endif
)
{
/* This is a properly formatted message so far.
See if it is a success or a failure. */
if (msg.error.err == EINTR &&
msg.head.msgh_size == sizeof msg.error)
{
/* EINTR response; poll for further responses
and then return quickly. */
err = EINTR;
goto poll;
}
if (msg.error.err ||
msg.head.msgh_size != sizeof msg.success ||
#ifdef MACH_MSG_TYPE_BIT
msg.success.result_type.word != inttype.word ||
#endif
(msg.success.result & SELECT_ALL) == 0)
{
/* Error or bogus reply. Simulate readiness. */
__mach_msg_destroy (&msg.head);
msg.success.result = SELECT_ALL;
}
/* Look up the respondent's reply port and record its
readiness. */
int had = got;
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type
&& d[i].reply_port == msg.head.msgh_local_port)
{
d[i].type &= msg.success.result;
d[i].type |= SELECT_RETURNED;
++got;
}
assert (got > had);
}
if (msg.head.msgh_remote_port != MACH_PORT_NULL)
__mach_port_deallocate (__mach_task_self (),
msg.head.msgh_remote_port);
if (got)
poll:
{
/* Poll for another message. */
to = 0;
options |= MACH_RCV_TIMEOUT;
}
}
if (err == MACH_RCV_TIMED_OUT)
/* This is the normal value for ERR. We might have timed out and
read no messages. Otherwise, after receiving the first message,
we poll for more messages. We receive with a timeout of 0 to
effect a poll, so ERR is MACH_RCV_TIMED_OUT when the poll finds no
message waiting. */
err = 0;
if (got)
/* At least one descriptor is known to be ready now, so we will
return success. */
err = 0;
}
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type)
__mach_port_destroy (__mach_task_self (), d[i].reply_port);
if ((firstfd != lastfd) && (portset != MACH_PORT_NULL))
/* Destroy PORTSET, but only if it's not actually the reply
port for a single descriptor (in which case it's destroyed
in the previous loop; not doing it here is just a bit more
efficient). */
__mach_port_destroy (__mach_task_self (), portset);
if (err)
{
/* FIXME: Only for ppoll */
if (sigmask)
__sigprocmask (SIG_SETMASK, &oset, NULL);
return __hurd_fail (err);
}
/* Fill in the `revents' members of the user's array. */
for (i = 0; i < nfds; ++i)
{
int type = d[i].type;
int_fast16_t revents = 0;
if (type & SELECT_RETURNED)
{
if (type & SELECT_READ)
revents |= POLLIN;
if (type & SELECT_WRITE)
revents |= POLLOUT;
if (type & SELECT_URG)
revents |= POLLPRI;
}
pollfds[i].revents = revents;
}
/* FIXME: Only for ppoll */
if (sigmask && __sigprocmask (SIG_SETMASK, &oset, NULL))
return -1;
return got;
break;
case SELECT:
/* Collect interested descriptors from the user's fd_set arguments.
Use local copies so we can't crash from user bogosity. */
if (readfds == NULL)
FD_ZERO (&rfds);
else
rfds = *readfds;
if (writefds == NULL)
FD_ZERO (&wfds);
else
wfds = *writefds;
if (exceptfds == NULL)
FD_ZERO (&xfds);
else
xfds = *exceptfds;
HURD_CRITICAL_BEGIN;
__mutex_lock (&_hurd_dtable_lock);
/* Collect the ports for interesting FDs. */
for (i = 0; i < nfds; ++i)
{
int type = 0;
if (readfds != NULL && FD_ISSET (i, &rfds))
type |= SELECT_READ;
if (writefds != NULL && FD_ISSET (i, &wfds))
type |= SELECT_WRITE;
if (exceptfds != NULL && FD_ISSET (i, &xfds))
type |= SELECT_URG;
d[i].type = type;
if (type)
{
d[i].cell = _hurd_dtable[i];
d[i].io_port = _hurd_port_get (&d[i].cell->port, &d[i].ulink);
if (d[i].io_port == MACH_PORT_NULL)
{
/* If one descriptor is bogus, we fail completely. */
while (i-- > 0)
if (d[i].type != 0)
_hurd_port_free (&d[i].cell->port, &d[i].ulink,
d[i].io_port);
break;
}
lastfd = i;
}
}
__mutex_unlock (&_hurd_dtable_lock);
HURD_CRITICAL_END;
if (i < nfds)
{
/* FIXME: Only for pselect */
if (sigmask)
__sigprocmask (SIG_SETMASK, &oset, NULL);
errno = EBADF;
return -1;
}
firstfd = 0;
err = 0;
got = 0;
/* Send them all io_select request messages. */
portset = MACH_PORT_NULL;
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type)
{
int type = d[i].type;
d[i].reply_port = __mach_reply_port ();
err = __io_select (d[i].io_port, d[i].reply_port,
/* Poll only if there's a single descriptor. */
(firstfd == lastfd) ? to : 0,
&type);
switch (err)
{
case MACH_RCV_TIMED_OUT:
/* No immediate response. This is normal. */
err = 0;
if (firstfd == lastfd)
/* When there's a single descriptor, we don't need a
portset, so just pretend we have one, but really
use the single reply port. */
portset = d[i].reply_port;
else if (got == 0)
/* We've got multiple reply ports, so we need a port set to
multiplex them. */
{
/* We will wait again for a reply later. */
if (portset == MACH_PORT_NULL)
/* Create the portset to receive all the replies on. */
err = __mach_port_allocate (__mach_task_self (),
MACH_PORT_RIGHT_PORT_SET,
&portset);
if (! err)
/* Put this reply port in the port set. */
__mach_port_move_member (__mach_task_self (),
d[i].reply_port, portset);
}
break;
default:
/* No other error should happen. Callers of select
don't expect to see errors, so we simulate
readiness of the erring object and the next call
hopefully will get the error again. */
type = SELECT_ALL;
/* FALLTHROUGH */
case 0:
/* We got an answer. */
if ((type & SELECT_ALL) == 0)
/* Bogus answer; treat like an error, as a fake positive. */
type = SELECT_ALL;
/* This port is already ready already. */
d[i].type &= type;
d[i].type |= SELECT_RETURNED;
++got;
break;
}
_hurd_port_free (&d[i].cell->port, &d[i].ulink, d[i].io_port);
}
/* Now wait for reply messages. */
if (!err && got == 0 && (firstfd != lastfd))
{
/* Now wait for io_select_reply messages on PORT,
timing out as appropriate. */
while ((msgerr = __mach_msg (&msg.head,
MACH_RCV_MSG | options,
0, sizeof msg, portset, to,
MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
{
/* We got a message. Decode it. */
if (msg.head.msgh_id == IO_SELECT_REPLY_MSGID &&
msg.head.msgh_size >= sizeof msg.error &&
!(msg.head.msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
#ifdef MACH_MSG_TYPE_BIT
msg.error.err_type.word == inttype.word
#endif
)
{
/* This is a properly formatted message so far.
See if it is a success or a failure. */
if (msg.error.err == EINTR &&
msg.head.msgh_size == sizeof msg.error)
{
/* EINTR response; poll for further responses
and then return quickly. */
err = EINTR;
goto poll2;
}
if (msg.error.err ||
msg.head.msgh_size != sizeof msg.success ||
#ifdef MACH_MSG_TYPE_BIT
msg.success.result_type.word != inttype.word ||
#endif
(msg.success.result & SELECT_ALL) == 0)
{
/* Error or bogus reply. Simulate readiness. */
__mach_msg_destroy (&msg.head);
msg.success.result = SELECT_ALL;
}
/* Look up the respondent's reply port and record its
readiness. */
int had = got;
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type
&& d[i].reply_port == msg.head.msgh_local_port)
{
d[i].type &= msg.success.result;
d[i].type |= SELECT_RETURNED;
++got;
}
assert (got > had);
}
if (msg.head.msgh_remote_port != MACH_PORT_NULL)
__mach_port_deallocate (__mach_task_self (),
msg.head.msgh_remote_port);
if (got)
poll2:
{
/* Poll for another message. */
to = 0;
options |= MACH_RCV_TIMEOUT;
}
}
if (err == MACH_RCV_TIMED_OUT)
/* This is the normal value for ERR. We might have timed out and
read no messages. Otherwise, after receiving the first message,
we poll for more messages. We receive with a timeout of 0 to
effect a poll, so ERR is MACH_RCV_TIMED_OUT when the poll finds no
message waiting. */
err = 0;
if (got)
/* At least one descriptor is known to be ready now, so we will
return success. */
err = 0;
}
for (i = firstfd; i <= lastfd; ++i)
if (d[i].type)
__mach_port_destroy (__mach_task_self (), d[i].reply_port);
if ((firstfd != lastfd) && (portset != MACH_PORT_NULL))
/* Destroy PORTSET, but only if it's not actually the reply port for a
single descriptor (in which case it's destroyed in the previous loop;
not doing it here is just a bit more efficient). */
__mach_port_destroy (__mach_task_self (), portset);
if (err)
{
/* FIXME: Only for pselect */
if (sigmask)
__sigprocmask (SIG_SETMASK, &oset, NULL);
return __hurd_fail (err);
}
/* Below we recalculate GOT to include an increment for each operation
allowed on each fd. */
got = 0;
/* Set the user bitarrays. We only ever have to clear bits, as all
desired ones are initially set. */
for (i = firstfd; i <= lastfd; ++i)
{
int type = d[i].type;
if ((type & SELECT_RETURNED) == 0)
type = 0;
if (type & SELECT_READ)
got++;
else if (readfds)
FD_CLR (i, readfds);
if (type & SELECT_WRITE)
got++;
else if (writefds)
FD_CLR (i, writefds);
if (type & SELECT_URG)
got++;
else if (exceptfds)
FD_CLR (i, exceptfds);
}
/* FIXME: Only for pselect */
if (sigmask && __sigprocmask (SIG_SETMASK, &oset, NULL))
return -1;
return got;
break;
default:
errno = EINVAL;
return -1;
} /* switch ispoll */
}
