[patch] who and stale utmp entries

[Tim Waugh]

Hi,

Here is a patch to prevent the who(1) command showing stale utmp
entries of user logins.

Tim.
*/

--- coreutils-5.2.1/src/who.c.stale-utmp        2005-03-23 13:43:55.000000000 
+0000
+++ coreutils-5.2.1/src/who.c   2005-03-23 13:46:44.000000000 +0000
@@ -27,6 +27,8 @@
 #include <config.h>
 #include <getopt.h>
 #include <stdio.h>
+#include <signal.h>
+#include <errno.h>
 
 #include <sys/types.h>
 #include "system.h"
@@ -521,7 +523,8 @@
 
   while (n--)
     {
-      if (UT_USER (utmp_buf)[0] && UT_TYPE (utmp_buf) == USER_PROCESS)
+      if (UT_USER (utmp_buf)[0] && UT_TYPE (utmp_buf) == USER_PROCESS &&
+         !(kill(utmp_buf->ut_pid, 0) < 0 && errno == ESRCH))
        {
          char *trimmed_name;
 
@@ -567,7 +570,8 @@
          strncmp (ttyname_b, utmp_buf->ut_line,
                   sizeof (utmp_buf->ut_line)) == 0)
        {
-         if (need_users && IS_USER_PROCESS (utmp_buf))
+         if (need_users && IS_USER_PROCESS (utmp_buf) &&
+             !(kill(utmp_buf->ut_pid, 0) < 0 && errno == ESRCH))
            print_user (utmp_buf);
          else if (need_runlevel && UT_TYPE (utmp_buf) == RUN_LVL)
            print_runlevel (utmp_buf);