move rusers(1) to poll(2)

[Jeremie Courreges-Anglas]

Low priority as there isn't really room for fd_set overflow here, but
I think we agree that moving to poll(2) is always a good thing. Seems
to work fine in a simple setup.

Not checking for POLLHUP since those are UDP sockets.

ok?


Index: rusers.c
===================================================================
RCS file: /cvs/src/usr.bin/rusers/rusers.c,v
retrieving revision 1.38
diff -u -p -p -u -r1.38 rusers.c
--- rusers.c 28 Mar 2016 11:06:09 -0000 1.38
+++ rusers.c 1 Aug 2016 21:29:29 -0000
@@ -66,6 +66,7 @@
#include <termios.h>
#include <unistd.h>
#include <limits.h>
+#include <poll.h>

#define MINIMUM(a, b) (((a) < (b)) ? (a) : (b))
#define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b))
@@ -486,9 +487,9 @@ allhosts(void)
AUTH *unix_auth;
size_t outlen[2];
int sock[2] = { -1, -1 };
- int i, maxfd, rval;
+ int i, rval;
u_long xid[2], port[2];
- fd_set *fds = NULL;
+ struct pollfd pfd[2];
struct sockaddr_in *sin, baddr;
struct rmtcallargs args;
struct rmtcallres res[2];
@@ -533,11 +534,6 @@ allhosts(void)
outlen[1] = xdr_getpos(&xdr);
xdr_destroy(&xdr);

- maxfd = MAXIMUM(sock[0], sock[1]) + 1;
- fds = calloc(howmany(maxfd, NFDBITS), sizeof(fd_mask));
- if (fds == NULL)
- err(1, NULL);
-
baddr.sin_len = sizeof(struct sockaddr_in);
baddr.sin_family = AF_INET;
baddr.sin_port = htons(PMAPPORT);
@@ -558,7 +554,7 @@ allhosts(void)
* a version 3 broadcast. On odd ones we send a version 2
* broadcast. This should give version 3 replies enough
* of an 'edge' over the old version 2 ones in most cases.
- * We select() waiting for replies for 5 seconds in between
+ * We poll() waiting for replies for 5 seconds in between
* each broadcast.
*/
for (i = 0; i < 6; i++) {
@@ -587,28 +583,30 @@ allhosts(void)
}

/*
- * We stay in the select loop for ~5 seconds
+ * We stay in the poll loop for ~5 seconds
*/
timeout.it_value.tv_sec = 5;
timeout.it_value.tv_usec = 0;
while (timerisset(&timeout.it_value)) {
- FD_SET(sock[0], fds);
- FD_SET(sock[1], fds);
+ pfd[0].fd = sock[0];
+ pfd[0].events = POLLIN;
+ pfd[1].fd = sock[1];
+ pfd[1].events = POLLIN;
setitimer(ITIMER_REAL, &timeout, NULL);
- rval = select(maxfd, fds, NULL, NULL, NULL);
+ rval = poll(pfd, 2, 0);
setitimer(ITIMER_REAL, NULL, &timeout);
if (rval == -1) {
if (errno == EINTR)
break;
- err(1, "select"); /* shouldn't happen */
+ err(1, "poll"); /* shouldn't happen */
}
- if (FD_ISSET(sock[1], fds)) {
+ if (pfd[1].revents & POLLIN) {
stat = get_reply(sock[1], (in_port_t)port[1],
xid[1], &msg[1], &res[1], rusers_reply_3);
if (stat != RPC_SUCCESS)
goto cleanup;
}
- if (FD_ISSET(sock[0], fds)) {
+ if (pfd[0].revents & POLLIN) {
stat = get_reply(sock[0], (in_port_t)port[0],
xid[0], &msg[0], &res[0], rusers_reply);
if (stat != RPC_SUCCESS)
@@ -619,7 +617,6 @@ allhosts(void)
cleanup:
if (ifap != NULL)
freeifaddrs(ifap);
- free(fds);
if (sock[0] >= 0)
(void)close(sock[0]);
if (sock[1] >= 0)

--
jca | PGP: 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE

[Todd C. Miller]

On Tue, 02 Aug 2016 18:51:13 +0200, Jeremie Courreges-Anglas wrote:

> Low priority as there isn't really room for fd_set overflow here, but
> I think we agree that moving to poll(2) is always a good thing. Seems
> to work fine in a simple setup.
>
> Not checking for POLLHUP since those are UDP sockets.

OK millert@

- todd