Ticket #16 (new enhancement)

Description

This patch adds an option "realuser" which, if enabled, sets the environment variables REALUSER to the user and the REALUID to the uid of the user who called op. We needed this functionality so that normal users can do a pmap (which needs root permissions to read /proc/...) on their processes (Example at the end).

diff -ruN op-1.32.orig/main.c op-1.32/main.c
--- op-1.32.orig/main.c	2005-12-08 01:48:25.000000000 +0100
+++ op-1.32/main.c	2006-01-17 11:14:01.000000000 +0100
@@ -74,6 +74,7 @@
 cmd_t	*First = NULL;
 var_t	*Variables = NULL;
 char *realuser = NULL;
+uid_t realuid;
 int gargc = -1;
 char **gargv = NULL;
 sigset_t sig_mask, old_sig_mask;
@@ -275,7 +276,7 @@
 	if (!read_conf && !read_conf_dir)
 		fatal(1, "could not open %s or any configuration files in %s (check that file permissions are 600)", OP_ACCESS, OP_ACCESS_DIR);
 
-	if ((pw = getpwuid(getuid())) == NULL) 
+	if ((pw = getpwuid(realuid = getuid())) == NULL) 
 		exit(1);
 	realuser = (char*)strdup(pw->pw_name);
 	strncpy(user, pw->pw_name, MAXSTRLEN);
@@ -1015,6 +1016,26 @@
 			continue;
 		}
 	}
+
+	if (FindOpt(cmd, "realuser") != NULL) {
+                if (strlen(realuser) + 10 > MAXSTRLEN)
+			fatal(1, "Username too long");
+ 
+	        sprintf(str, "REALUSER=%s", realuser);
+		new_envp[curenv] = malloc(strlen(str) + 1);
+		strcpy(new_envp[curenv], str);
+		if (curenv + 1 >= MAXENV)
+			fatal(1, "%s: environment length exceeded", cmd->name);
+		++curenv;
+
+        	sprintf(str, "REALUID=%d", realuid);
+		new_envp[curenv] = malloc(strlen(str) + 1);
+		strcpy(new_envp[curenv], str);
+		if (curenv + 1 >= MAXENV)
+			fatal(1, "%s: environment length exceeded", cmd->name);
+		++curenv;
+	}
+
 	new_envp[curenv] = NULL;
 
 	/* --------------------------------------------------- */ 

pmap            /bin/sh -c '
                        if [ -z "$*" ]; then
                                /usr/bin/pmap
                                exit 0
                        fi

                        for arg in $*; do
                                case "$arg" in
                                        [0-9]*)
                                                /usr/binpgrep -U $REALUID | /usr/bin/grep "^$arg$" >/dev/null 2>&1
                                                if [ $? -ne 0 ]; then
                                                        echo "permission denied by op"
                                                        exit 0
                                                fi
                                                ;;
                                esac
                        done

                        /usr/bin/pmap $*
                ';
                users=twls
                realuser
                help=" "
                $*=(-r|-x|-l|[0-9]+)