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Path: utzoo!mnetor!seismo!ut-sally!husc6!cmcl2!brl-adm!adm!drears@ARDEC.arpa
From: drears@ARDEC.arpa (FSAC)
Newsgroups: comp.unix.wizards
Subject: Re:  Adding to Environment Pointers
Message-ID: <7950@brl-adm.ARPA>
Date: Mon, 22-Jun-87 15:20:39 EDT
Article-I.D.: brl-adm.7950
Posted: Mon Jun 22 15:20:39 1987
Date-Received: Tue, 23-Jun-87 04:56:45 EDT
Sender: news@brl-adm.ARPA
Lines: 62


  I am trying to write a program that sets up a environment and then
execs a shell.  I am trying to build my environmental poingters one
by one but when I run the compiled program I get the error message:
"Trace/BPT trap".  I am running ULtrik 2.0 on a VAX 8600.  ANy
comments would be appreciated.  I have tried using the putenv(3)
command put it doesn't always work right. He is the code that matters:



#include <stdio.h>
#include <pwd.h>
#include <errno.h>

#define	PATH	"/usr/pica/bin:/bin:/usr/ucb:/usr/usg:/usr/brl/bin:/local/bin"

extern int	errno;

main(argc,argv,envp)
int	argc;
char	*argv[], *envp[];
{
	FILE	*fopen(), *fp;
	int result;
	int	uid, auid, agid;
	char	*identity, username[15];
	char	command[300], userfile[50], *fgets(), line[15], *ret;
	char	*home, *malloc(); 
	char	*newarg[], *newenvp[]; 
	struct	passwd *pwp, *getpwnam(), *getpwuid();

	identity=argv[0];

	/*  rest of code is deleted for space consideration reason
	    i get home define from the password entry */

	if (chdir(home)){
		fprintf(stderr,"ERRNO=%d",errno);
		fprintf(stderr,"%s: Could not cd to %s\n",identity,home);
		fprintf(stderr,"ERRNO=%d",errno);
		exit(-1);
	}

	/*  set up the envirnoment    */

	newarg[0]="/bin/sh";
	newenvp[0]=PATH;
	sprintf(newenvp[1],"HOME=%s",home);
	sprintf(newenvp[2],"PS1=%s>",identity);
	sprintf(newenvp[3],"MAIL=%s/mailbox",home);
	sprintf(newenvp[4],"USER=%s",identity);
	system("/bin/sh");

	/*  exec the shell with the new identity */

	exect("bin/sh",newarg,newenvp);


}


Dennis