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[src/trunk]: src/lib/librumphijack Support dual kernel select() by emulating ...
details: https://anonhg.NetBSD.org/src/rev/c7f2fab9e76a
branches: trunk
changeset: 760597:c7f2fab9e76a
user: pooka <pooka%NetBSD.org@localhost>
date: Sat Jan 08 21:30:24 2011 +0000
description:
Support dual kernel select() by emulating it with pollts(). It
would have been much easier if up to and including 5.0 we wouldn't
silently cap the nfds argument to poll(!!!).
Makes things like socket(1) work out-of-the-box, and pretty much
every other decidedly prehistoric select() user.
(netcat is a slight exception since it sets FD_SETSIZE, a.k.a.
interface-of-the-year, to 16)
diffstat:
lib/librumphijack/hijack.c | 163 +++++++++++++++++++++++++-------------------
1 files changed, 93 insertions(+), 70 deletions(-)
diffs (222 lines):
diff -r 6a6e01fd2a52 -r c7f2fab9e76a lib/librumphijack/hijack.c
--- a/lib/librumphijack/hijack.c Sat Jan 08 20:37:05 2011 +0000
+++ b/lib/librumphijack/hijack.c Sat Jan 08 21:30:24 2011 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: hijack.c,v 1.3 2011/01/08 18:11:46 pooka Exp $ */
+/* $NetBSD: hijack.c,v 1.4 2011/01/08 21:30:24 pooka Exp $ */
/*-
* Copyright (c) 2011 Antti Kantee. All Rights Reserved.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: hijack.c,v 1.3 2011/01/08 18:11:46 pooka Exp $");
+__RCSID("$NetBSD: hijack.c,v 1.4 2011/01/08 21:30:24 pooka Exp $");
#include <sys/param.h>
#include <sys/types.h>
@@ -62,7 +62,7 @@
RUMPCALL_WRITE, RUMPCALL_WRITEV,
RUMPCALL_IOCTL, RUMPCALL_FCNTL,
RUMPCALL_CLOSE,
- RUMPCALL_SELECT, RUMPCALL_POLLTS,
+ RUMPCALL_POLLTS,
RUMPCALL__NUM
};
@@ -88,7 +88,6 @@
"ioctl",
"fcntl",
"close",
- "__select50",
"__pollts50",
};
@@ -99,8 +98,6 @@
static int (*host_ioctl)(int, unsigned long, ...);
static int (*host_fcntl)(int, int, ...);
static int (*host_close)(int);
-static int (*host_select)(int, fd_set *, fd_set *, fd_set *,
- struct timeval *);
static int (*host_pollts)(struct pollfd *, nfds_t,
const struct timespec *, const sigset_t *);
static pid_t (*host_fork)(void);
@@ -143,7 +140,6 @@
host_ioctl = dlsym(RTLD_NEXT, "ioctl");
host_fcntl = dlsym(RTLD_NEXT, "fcntl");
host_close = dlsym(RTLD_NEXT, "close");
- host_select = dlsym(RTLD_NEXT, "select");
host_pollts = dlsym(RTLD_NEXT, "pollts");
host_fork = dlsym(RTLD_NEXT, "fork");
host_dup2 = dlsym(RTLD_NEXT, "dup2");
@@ -586,79 +582,106 @@
return op_close(fd);
}
-/*
- * select() has more than one implication. e.g. we cannot know
- * the caller's FD_SETSIZE. So just assume something and hope.
- */
-static void
-checkset(fd_set *setti, int nfds, int *hostcall, int *rumpcall)
-{
- int i;
-
- if (!setti)
- return;
-
- for (i = 0; i < MIN(nfds, FD_SETSIZE); i++) {
- if (FD_ISSET(i, setti)) {
- if (fd_isrump(i))
- *rumpcall = 1;
- else
- *hostcall = 1;
- }
- }
-}
-
-static void
-adjustset(fd_set *setti, int nfds, int (*fdadj)(int))
-{
- int fd, i;
-
- if (!setti)
- return;
-
- for (i = 0; i < MIN(nfds, FD_SETSIZE); i++) {
- if (FD_ISSET(i, setti)) {
- FD_CLR(i, setti);
- fd = fdadj(fd);
- FD_SET(fd, setti);
- }
- }
-}
-
int
select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
struct timeval *timeout)
{
- int (*op_select)(int, fd_set *, fd_set *, fd_set *, struct timeval *);
- int hostcall = 0, rumpcall = 0;
- int rv;
+ struct pollfd *pfds;
+ struct timespec ts, *tsp = NULL;
+ nfds_t i, j, realnfds;
+ int rv, incr;
- checkset(readfds, nfds, &hostcall, &rumpcall);
- checkset(writefds, nfds, &hostcall, &rumpcall);
- checkset(exceptfds, nfds, &hostcall, &rumpcall);
-
- if (hostcall && rumpcall) {
- fprintf(stderr, "cannot select() two kernels! (fixme)\n");
- return EINVAL;
+ /*
+ * Well, first we must scan the fds to figure out how many
+ * fds there really are. This is because up to and including
+ * nb5 poll() silently refuses nfds > process_open_fds.
+ * Seems to be fixed in current, thank the maker.
+ * god damn cluster...bomb.
+ */
+
+ for (i = 0, realnfds = 0; i < nfds; i++) {
+ if (readfds && FD_ISSET(i, readfds)) {
+ realnfds++;
+ continue;
+ }
+ if (writefds && FD_ISSET(i, writefds)) {
+ realnfds++;
+ continue;
+ }
+ if (exceptfds && FD_ISSET(i, exceptfds)) {
+ realnfds++;
+ continue;
+ }
}
- if (hostcall) {
- op_select = host_select;
- } else {
- adjustset(readfds, nfds, fd_host2rump);
- adjustset(writefds, nfds, fd_host2rump);
- adjustset(exceptfds, nfds, fd_host2rump);
- op_select = rumpcalls[RUMPCALL_SELECT];
+ pfds = malloc(sizeof(*pfds) * realnfds);
+ if (!pfds)
+ return -1;
+
+ for (i = 0, j = 0; i < nfds; i++) {
+ incr = 0;
+ pfds[j].events = pfds[j].revents = 0;
+ if (readfds && FD_ISSET(i, readfds)) {
+ pfds[j].fd = i;
+ pfds[j].events |= POLLIN;
+ incr=1;
+ }
+ if (writefds && FD_ISSET(i, writefds)) {
+ pfds[j].fd = i;
+ pfds[j].events |= POLLOUT;
+ incr=1;
+ }
+ if (exceptfds && FD_ISSET(i, exceptfds)) {
+ pfds[j].fd = i;
+ pfds[j].events |= POLLHUP|POLLERR;
+ incr=1;
+ }
+ if (incr)
+ j++;
}
- DPRINTF(("select\n"));
- rv = op_select(nfds+HIJACK_SELECT,
- readfds, writefds, exceptfds, timeout);
- if (rumpcall) {
- adjustset(readfds, nfds, fd_rump2host);
- adjustset(writefds, nfds, fd_rump2host);
- adjustset(exceptfds, nfds, fd_rump2host);
+ if (timeout) {
+ TIMEVAL_TO_TIMESPEC(timeout, &ts);
+ tsp = &ts;
+ }
+ rv = pollts(pfds, realnfds, tsp, NULL);
+ if (rv <= 0)
+ goto out;
+
+ /*
+ * ok, harvest results. first zero out entries (can't use
+ * FD_ZERO for the obvious select-me-not reason). whee.
+ */
+ for (i = 0; i < nfds; i++) {
+ if (readfds)
+ FD_CLR(i, readfds);
+ if (writefds)
+ FD_CLR(i, writefds);
+ if (exceptfds)
+ FD_CLR(i, exceptfds);
}
+
+ /* and then plug in the results */
+ for (i = 0; i < realnfds; i++) {
+ if (readfds) {
+ if (pfds[i].revents & POLLIN) {
+ FD_SET(pfds[i].fd, readfds);
+ }
+ }
+ if (writefds) {
+ if (pfds[i].revents & POLLOUT) {
+ FD_SET(pfds[i].fd, writefds);
+ }
+ }
+ if (exceptfds) {
+ if (pfds[i].revents & (POLLHUP|POLLERR)) {
+ FD_SET(pfds[i].fd, exceptfds);
+ }
+ }
+ }
+
+ out:
+ free(pfds);
return rv;
}
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