Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!uunet!bfmny0!tneff
From: tneff@bfmny0.UUCP (Tom Neff)
Newsgroups: alt.sources
Subject: euser - display the effective user name, SysV-ish
Message-ID: <14448@bfmny0.UUCP>
Date: 7 Jul 89 23:29:21 GMT
Reply-To: tneff@bfmny0.UUCP (Tom Neff)
Organization: ^
Lines: 62
Summary:
Expires:
References:
Sender:
Followup-To:
Distribution:
Keywords:

If you need a FAST way to generate the name of your current effective
user (including the effects of su(1) etc), this works.  It's not fancy.
Obviously it has to read /etc/passwd.  Feel free to hack and pass
around.

#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create:
#	euser.c
# This archive created: Wed Jul  5 19:58:33 1989
export PATH; PATH=/bin:/usr/bin:$PATH
if test -f 'euser.c'
then
	echo shar: "will not over-write existing file 'euser.c'"
else
sed 's/^X//' << \SHAR_EOF > 'euser.c'
X/*
X	euser.c		rev: 05-Jul-89		Tom Neff
X
X	Display the name of our effective user at the moment.
X
X	System V-ish.  Have a blast.
X
X	Uses /etc/passwd.
X */
X
X#include <stdio.h>
X#include <string.h>
X
Xunsigned short geteuid(), euid;
X
XFILE *pass;
Xchar line[256], *name;
Xint uid = 0;
X
Xmain()
X{
X	euid = geteuid();
X	if ((pass = fopen("/etc/passwd","r")) == NULL)
X		exit(2);
X	while (fgets(line, sizeof(line), pass) != NULL)
X	{
X		name = strtok(line, ":");
X		strtok(NULL, ":");
X		uid = atoi(strtok(NULL, ":"));
X		if (euid == uid)
X		{
X			puts(name);
X			exit(0);
X		}
X	}
X	exit(1);
X}
SHAR_EOF
fi
exit 0
#	End of shell archive
-- 
"My God, Thiokol, when do you     \\	Tom Neff
want me to launch -- next April?"  \\	uunet!bfmny0!tneff