Date: Sun, 30 Sep 2001 23:29:35 +0400 (MSD) From: andrew@nas.dgap.mipt.ru To: FreeBSD-gnats-submit@freebsd.org Subject: bin/30939: top(1) behaves badly when it loses terminal Message-ID: <200109301929.f8UJTZS24778@nas.dgap.mipt.ru>
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>Number: 30939
>Category: bin
>Synopsis: top(1) behaves badly when it loses terminal
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sun Sep 30 12:30:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator: Andrew L. Neporada
>Release: FreeBSD 4.3-RELEASE i386
>Organization:
>Environment:
System: FreeBSD nas.dgap.mipt.ru 4.3-RELEASE FreeBSD 4.3-RELEASE #0: Mon May 7 20:16:53 MSD 2001 root@nas.dgap.mipt.ru:/usr/obj/usr/src/sys/NAS i386
>Description:
After losing its control terminal top(1) eats all available CPU resources
(when running under root privileges).
>How-To-Repeat:
Example session:
andrew@nas > ssh localhost
socket: Protocol not supported
andrew@localhost's password:
.
.
.
andrew@nas > su
Password:
nas# top
Then enter ~. to kill ssh and launch top or ps waux.
>Fix:
Maybe it is better to just exit() instead of sleep() but anyway ...
--- contrib/top/top.c.orig Sun Sep 30 21:30:08 2001
+++ contrib/top/top.c Sun Sep 30 22:51:23 2001
@@ -157,6 +157,7 @@
int topn = Default_TOPN;
int delay = Default_DELAY;
int displays = 0; /* indicates unspecified */
+ int sel_ret = 0;
time_t curr_time;
char *(*get_userid)() = username;
char *uname_field = "USERNAME";
@@ -711,7 +712,9 @@
}
/* wait for either input or the end of the delay period */
- if (select(32, &readfds, (fd_set *)NULL, (fd_set *)NULL, &timeout) > 0)
+ sel_ret = select(2, &readfds, (fd_set *)NULL, (fd_set *)NULL,
+ &timeout);
+ if (sel_ret > 0)
{
int newval;
char *errmsg;
@@ -721,7 +724,12 @@
/* now read it and convert to command strchr */
/* (use "change" as a temporary to hold strchr) */
- (void) read(0, &ch, 1);
+ /* sleep if input from stdin causes error */
+ if (read(0, &ch, 1) != 1)
+ {
+ ch = '\r';
+ sleep(delay);
+ }
if ((iptr = strchr(command_chars, ch)) == NULL)
{
if (ch != '\r' && ch != '\n')
@@ -960,6 +968,11 @@
/* flush out stuff that may have been written */
fflush(stdout);
+ }
+ /* sleep if input from stdin causes error */
+ if (sel_ret < 0)
+ {
+ sleep(delay);
}
}
}
>Release-Note:
>Audit-Trail:
>Unformatted:
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