Path: utzoo!dciem!nrcaer!scs!spl1!laidbak!att!pacbell!ames!mailrus!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!uw-beaver!ssc-vax!uvicctr!tholm
From: tholm@uvicctr.UUCP (Terrence W. Holm)
Newsgroups: comp.os.minix
Subject: su(1) passing the environment
Message-ID: <431@uvicctr.UUCP>
Date: 2 Jun 88 00:34:53 GMT
Article-I.D.: uvicctr.431
Reply-To: tholm@uvicctr.UUCP (Terrence W. Holm)
Organization: University of Victoria, Victoria B.C. Canada
Lines: 123

EFTH Minix report #15  - June 1988 -  su(1) and the environment


This is a modified su(1) that properly passes the environment.

Note: putenv(3) must be installed (see EFTH report #2).

A "man" page is included.


echo x - su.1
gres '^X' '' > su.1 << '/'
XNAME
X    su(1)		- superimpose another user's shell
X
XSYNOPSIS
X    su  [ username ]
X
XDESCRIPTION
X    This performs a log-in of another user, a new process is
X    used for the appropriate shell. Your current shell is not
X    destroyed, as occurs when using login(1).
X
X    If "username" is not given it defaults to "root" (the super-
X    user). A password will be asked for if "username" requires one.
X
X    The group and user id are changed for the new username.
X    The environment entries $HOME and $SHELL are set up according
X    to the new username's entry in the password file, but the
X    rest of the environment is passed untouched. The current
X    directory is not changed.
X
XFILES
X    /etc/passwd
X
XSEE ALSO
X    login(1)
/
echo x - su.c
gres '^X' '' > su.c << '/'
X/* su - become super-user		Author: Patrick van Kleef */
X
X/* Modified to set up HOME and SHELL in the environment, and pass */
X/* the rest of the environment to the new shell. 1987-Oct-7 EFTH  */
X
X#include "sgtty.h"
X#include "stdio.h"
X#include "pwd.h"
X
Xextern  char  **environ;
X
Xchar *malloc();
X
X
Xmain (argc, argv)
Xint   argc;
Xchar *argv[];
X{
X	register char   *name;
X	char   *crypt ();
X	char   *shell = "/bin/sh";
X	char   *_home, *_shell;
X	int     nr;
X	char    password[14];
X	struct sgttyb   args;
X	register struct passwd *pwd;
X	struct passwd *getpwnam ();
X
X	if (argc > 1)
X		name = argv[1];
X	else
X		name = "root";
X
X	if ((pwd = getpwnam (name)) == 0) {
X		std_err("Unknown id: ");
X		std_err(name);
X		std_err("\n");
X		exit (1);
X	}
X
X	if (pwd->pw_passwd[0] != '\0' && getuid()!= 0) {
X		std_err("Password: ");
X		ioctl (0, TIOCGETP, &args);	/* get parameters */
X		args.sg_flags = args.sg_flags & (~ECHO);
X		ioctl (0, TIOCSETP, &args); 
X		nr = read (0, password, 14);
X		password[nr - 1] = 0;
X		putc('\n',stderr);
X		args.sg_flags = args.sg_flags | ECHO;
X		ioctl (0, TIOCSETP, &args); 
X		if (strcmp (pwd->pw_passwd, crypt (password, pwd->pw_passwd))) {
X			std_err("Sorry\n");
X			exit (2);
X		}
X	}
X	setgid (pwd->pw_gid);
X	setuid (pwd->pw_uid);
X	if (pwd->pw_shell[0])
X		shell = pwd->pw_shell;
X
X	/*  Set up HOME and SHELL in the environment  */
X
X	_home = malloc( strlen(pwd->pw_dir) + 6 );
X	strcpy( _home, "HOME=" );
X	strcat( _home, pwd->pw_dir );
X	putenv( _home );
X
X	_shell = malloc( strlen(shell) + 7 );
X	strcpy( _shell, "SHELL=" );
X	strcat( _shell, shell );
X	putenv( _shell );
X
X	execle( shell, shell, (char *) 0, environ );
X	std_err("No shell\n");
X	exit (3);
X}
/
--------------------------------------------------------------------
               Edwin L. Froese
                  uw-beaver!ubc-cs!mprg!handel!froese

               Terrence W. Holm
                  {uw-beaver,ubc-cs}!uvicctr!sirius!tholm