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rlogin(1): Replace select(2) with poll(2).

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Obtanied from:	NetBSD (CVS Rev. 1.27 - 1.28)
This commit is contained in:
Pedro F. Giffuni 2016-02-26 20:02:01 +00:00
parent 563a01a1da
commit 2e0050835a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=296109
1 changed files with 22 additions and 42 deletions
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64
libexec/rlogind/rlogind.c
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@ -76,6 +76,7 @@ __FBSDID("$FreeBSD$");
#include <errno.h>
#include <libutil.h>
#include <paths.h>
#include <poll.h>
#include <pwd.h>
#include <syslog.h>
#include <stdio.h>
@ -350,34 +351,27 @@ protocol(int f, int p)
nfd = f + 1;
else
nfd = p + 1;
if (nfd > FD_SETSIZE) {
syslog(LOG_ERR, "select mask too small, increase FD_SETSIZE");
fatal(f, "internal error (select mask too small)", 0);
}
for (;;) {
fd_set ibits, obits, ebits, *omask;
struct pollfd set[2];
FD_ZERO(&ebits);
FD_ZERO(&ibits);
FD_ZERO(&obits);
omask = (fd_set *)NULL;
if (fcc) {
FD_SET(p, &obits);
omask = &obits;
} else
FD_SET(f, &ibits);
set[0].fd = p;
set[0].events = POLLPRI;
set[1].fd = f;
set[1].events = 0;
if (fcc)
set[0].events |= POLLOUT;
else
set[1].events |= POLLIN;
if (pcc >= 0) {
if (pcc) {
FD_SET(f, &obits);
omask = &obits;
} else
FD_SET(p, &ibits);
if (pcc)
set[1].events |= POLLOUT;
else
set[0].events |= POLLIN;
}
FD_SET(p, &ebits);
if ((n = select(nfd, &ibits, omask, &ebits, 0)) < 0) {
if ((n = poll(set, 2, INFTIM)) < 0) {
if (errno == EINTR)
continue;
fatal(f, "select", 1);
fatal(f, "poll", 1);
}
if (n == 0) {
/* shouldn't happen... */
@ -385,18 +379,16 @@ protocol(int f, int p)
continue;
}
#define pkcontrol(c) ((c)&(TIOCPKT_FLUSHWRITE|TIOCPKT_NOSTOP|TIOCPKT_DOSTOP))
if (FD_ISSET(p, &ebits)) {
if (set[0].revents & POLLPRI) {
cc = read(p, &cntl, 1);
if (cc == 1 && pkcontrol(cntl)) {
cntl |= oobdata[0];
send(f, &cntl, 1, MSG_OOB);
if (cntl & TIOCPKT_FLUSHWRITE) {
if (cntl & TIOCPKT_FLUSHWRITE)
pcc = 0;
FD_CLR(p, &ibits);
}
}
}
if (FD_ISSET(f, &ibits)) {
if (set[1].revents & POLLIN) {
fcc = read(f, fibuf, sizeof(fibuf));
if (fcc < 0 && errno == EWOULDBLOCK)
fcc = 0;
@ -422,11 +414,10 @@ protocol(int f, int p)
goto top; /* n^2 */
}
}
FD_SET(p, &obits); /* try write */
}
}
if (FD_ISSET(p, &obits) && fcc > 0) {
if (set[0].revents & POLLOUT && fcc > 0) {
cc = write(p, fbp, fcc);
if (cc > 0) {
fcc -= cc;
@ -434,7 +425,7 @@ protocol(int f, int p)
}
}
if (FD_ISSET(p, &ibits)) {
if (set[0].revents & POLLIN) {
pcc = read(p, pibuf, sizeof (pibuf));
pbp = pibuf;
if (pcc < 0 && errno == EWOULDBLOCK)
@ -443,7 +434,6 @@ protocol(int f, int p)
break;
else if (pibuf[0] == 0) {
pbp++, pcc--;
FD_SET(f, &obits); /* try write */
} else {
if (pkcontrol(pibuf[0])) {
pibuf[0] |= oobdata[0];
@ -452,18 +442,8 @@ protocol(int f, int p)
pcc = 0;
}
}
if ((FD_ISSET(f, &obits)) && pcc > 0) {
if (set[1].revents & POLLOUT && pcc > 0) {
cc = write(f, pbp, pcc);
if (cc < 0 && errno == EWOULDBLOCK) {
/*
* This happens when we try write after read
* from p, but some old kernels balk at large
* writes even when select returns true.
*/
if (!FD_ISSET(p, &ibits))
sleep(5);
continue;
}
if (cc > 0) {
pcc -= cc;
pbp += cc;