diff options
Diffstat (limited to 'sysdeps/mach/hurd/select.c')
| -rw-r--r-- | sysdeps/mach/hurd/select.c | 189 |
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; |