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Diffstat (limited to 'sysdeps/mach/hurd/select.c')
-rw-r--r--sysdeps/mach/hurd/select.c189
1 files changed, 101 insertions, 88 deletions
diff --git a/sysdeps/mach/hurd/select.c b/sysdeps/mach/hurd/select.c
index 8e78adb1bc..188f65b3c0 100644
--- a/sysdeps/mach/hurd/select.c
+++ b/sysdeps/mach/hurd/select.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
+/* Copyright (C) 1991, 92, 93, 94, 95, 96 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
@@ -22,6 +22,7 @@ Cambridge, MA 02139, USA. */
#include <hurd/fd.h>
#include <stdlib.h>
#include <string.h>
+#include <assert.h>
/* All user select types. */
#define SELECT_ALL (SELECT_READ | SELECT_WRITE | SELECT_URG)
@@ -41,12 +42,8 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
fd_set *exceptfds AND struct timeval *timeout)
{
int i;
- mach_port_t port;
+ mach_port_t portset;
int got;
- int *types;
- struct hurd_userlink *ulink;
- mach_port_t *ports;
- struct hurd_fd **cells;
error_t err;
fd_set rfds, wfds, xfds;
int firstfd, lastfd;
@@ -54,6 +51,14 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
(timeout->tv_sec * 1000 +
timeout->tv_usec / 1000) :
0);
+ struct
+ {
+ struct hurd_userlink ulink;
+ struct hurd_fd *cell;
+ mach_port_t io_port;
+ int type;
+ mach_port_t reply_port;
+ } d[nfds];
/* Use local copies so we can't crash from user bogosity. */
if (readfds == NULL)
@@ -76,10 +81,6 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
nfds = _hurd_dtablesize;
/* Collect the ports for interesting FDs. */
- cells = __alloca (nfds * sizeof (*cells));
- ports = __alloca (nfds * sizeof (*ports));
- types = __alloca (nfds * sizeof (*types));
- ulink = __alloca (nfds * sizeof (*ulink));
firstfd = lastfd = -1;
for (i = 0; i < nfds; ++i)
{
@@ -90,16 +91,16 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
type |= SELECT_WRITE;
if (exceptfds != NULL && FD_ISSET (i, &xfds))
type |= SELECT_URG;
- types[i] = type;
+ d[i].type = type;
if (type)
{
- cells[i] = _hurd_dtable[i];
- ports[i] = _hurd_port_get (&cells[i]->port, &ulink[i]);
- if (ports[i] == MACH_PORT_NULL)
+ 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)
- _hurd_port_free (&cells[i]->port, &ulink[i], ports[i]);
+ _hurd_port_free (&d[i].cell->port, &d[i].ulink, d[i].io_port);
errno = EBADF;
break;
}
@@ -115,58 +116,63 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
if (i < nfds)
return -1;
- /* Get a port to receive the io_select_reply messages on. */
- port = __mach_reply_port ();
-
/* Send them all io_select request messages. */
- got = 0;
err = 0;
+ got = 0;
+ portset = MACH_PORT_NULL;
for (i = firstfd; i <= lastfd; ++i)
- if (types[i])
+ if (d[i].type)
{
- if (!err)
+ int type = d[i].type;
+ d[i].reply_port = __mach_reply_port ();
+ err = __io_select (d[i].io_port, d[i].reply_port,
+ /* Poll for each but the last. */
+ (i == lastfd && got == 0) ? to : 0,
+ &type);
+ switch (err)
{
- int tag = i;
- int type = types[i];
- err = __io_select (ports[i], port,
- /* Poll for each but the last. */
- (i == lastfd && got == 0) ? to : 0,
- &type, &tag);
- switch (err)
+ case MACH_RCV_TIMED_OUT:
+ /* No immediate response. This is normal. */
+ err = 0;
+ if (got == 0)
{
- case MACH_RCV_TIMED_OUT:
- /* No immediate response. This is normal. */
- err = 0;
- break;
-
- case 0:
- /* We got an answer. This is not necessarily the answer to
- the query we sent just now. It may correspond to any
- prior query which timed out before its answer arrived. */
- if (tag < 0 || tag > i || (type & SELECT_ALL) == 0)
- /* This is not a proper answer to any query we have yet
- made. */
- err = EGRATUITOUS;
- else
- {
- /* Some port is ready. TAG tells us which. */
- types[tag] &= type;
- types[tag] |= SELECT_RETURNED;
- ++got;
- }
- break;
-
- default:
- /* Any other error kills us.
- But we must continue to loop to free the ports. */
- break;
+ /* 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 (&cells[i]->port, &ulink[i], ports[i]);
+ _hurd_port_free (&d[i].cell->port, &d[i].ulink, d[i].io_port);
}
/* Now wait for reply messages. */
- if (!err && got == 0 && port != MACH_PORT_NULL)
+ if (!err && got == 0)
{
/* Now wait for io_select_reply messages on PORT,
timing out as appropriate. */
@@ -187,15 +193,13 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
error_t err;
mach_msg_type_t result_type;
int result;
- mach_msg_type_t tag_type;
- int tag;
} success;
} 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, port, to,
+ 0, sizeof msg, portset, to,
MACH_PORT_NULL)) == MACH_MSG_SUCCESS)
{
/* We got a message. Decode it. */
@@ -209,34 +213,45 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
{
/* This is a properly formatted message so far.
See if it is a success or a failure. */
- if (msg.error.err)
+ if (msg.error.err == EINTR &&
+ msg.head.msgh_size == sizeof msg.error)
{
- err = msg.error.err;
- if (msg.head.msgh_size != sizeof msg.error)
- __mach_msg_destroy (&msg);
+ /* EINTR response; poll for further responses
+ and then return quickly. */
+ err = EINTR;
+ goto poll;
}
- else if (msg.head.msgh_size != sizeof msg.success ||
- *(int *) &msg.success.tag_type != *(int *) &inttype ||
- *(int *) &msg.success.result_type != *(int *) &inttype)
- __mach_msg_destroy (&msg);
- else if ((msg.success.result & SELECT_ALL) == 0 ||
- msg.success.tag < firstfd || msg.success.tag > lastfd)
- err = EGRATUITOUS;
- else
+ if (msg.error.err ||
+ msg.head.msgh_size != sizeof msg.success ||
+ *(int *) &msg.success.result_type != *(int *) &inttype ||
+ (msg.success.result & SELECT_ALL) == 0)
{
- /* This is a winning io_select_reply message!
- Record the readiness it indicates and send a reply. */
- types[msg.success.tag] &= msg.success.result;
- types[msg.success.tag] |= SELECT_RETURNED;
- ++got;
+ /* Error or bogus reply. Simulate readiness. */
+ __mach_msg_destroy (&msg);
+ msg.success.result = SELECT_ALL;
}
+
+ /* Look up the respondant'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 || err == EINTR)
+ if (got)
+ poll:
{
/* Poll for another message. */
to = 0;
@@ -252,19 +267,17 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
message waiting. */
err = 0;
- if (got && err == EINTR)
- /* Some calls were interrupted, but at least one descriptor
- is known to be ready now, so we will return success. */
+ if (got)
+ /* At least one descriptor is known to be ready now, so we will
+ return success. */
err = 0;
}
- if (port != MACH_PORT_NULL)
- /* We must destroy the port if we made some select requests
- that might send notification on that port after we no longer care.
- If the port were reused, that notification could confuse the next
- select call to use the port. The notification might be valid,
- but the descriptor may have changed to a different server. */
- __mach_port_destroy (__mach_task_self (), port);
+ for (i = firstfd; i <= lastfd; ++i)
+ if (d[i].type)
+ __mach_port_destroy (__mach_task_self (), d[i].reply_port);
+ if (portset != MACH_PORT_NULL)
+ __mach_port_destroy (__mach_task_self (), portset);
if (err)
return __hurd_fail (err);
@@ -277,7 +290,7 @@ DEFUN(__select, (nfds, readfds, writefds, exceptfds, timeout),
ones are initially set. */
for (i = firstfd; i <= lastfd; ++i)
{
- int type = types[i];
+ int type = d[i].type;
if ((type & SELECT_RETURNED) == 0)
type = 0;