fix firecfg --guide

src/firecfg/firejail-welcome.sh

@@ -4,22 +4,21 @@
 # Copyright (C) 2020-2022 Firejail Authors
 # License GPL v2
 #
-# Usage: firejail-welcome PROGRAM SYSCONFDIR
+# Usage: firejail-welcome PROGRAM SYSCONFDIR USER_NAME
 # where PROGRAM is detected and driven by firecfg.
 # SYSCONFDIR is most of the time /etc/firejail.
 #
 # The plan is to go with zenity by default. If zenity is not installed
 # we will provide a console-only replacement in /usr/lib/firejail/fzenity
 #
 
-PROGRAM=$1
-SYSCONFDIR=$2
-
-if ! command -v "$PROGRAM" >/dev/null; then
-	echo "Please install $PROGRAM."
+if ! command -v "$1" >/dev/null; then
+	echo "Please install $1."
 	exit 1
 fi
 
+PROGRAM="sudo -u $3 $1"
+SYSCONFDIR=$2
 export LANG=en_US.UTF8
 
 TITLE="Firejail Configuration Guide"
@@ -165,7 +164,7 @@ Now, I will apply the changes. This is what I will do:
 
 
 EOM
-
+MSG_RUN+="\n\n"
 if [[ "$run_firecfg" == "true" ]]; then
 	MSG_RUN+="     * enable Firejail for all recognized programs\n"
 fi

src/firecfg/main.c

@@ -443,11 +443,15 @@ int main(int argc, char **argv) {
 	}
 
 	if (arg_guide) {
-		int status = system("sudo "LIBDIR "/firejail/firejail-welcome.sh zenity " SYSCONFDIR);
+		char *cmd;
+		if (asprintf(&cmd, "sudo %s/firejail/firejail-welcome.sh /usr/bin/zenity %s %s", LIBDIR, SYSCONFDIR, user) == -1)
+			errExit("asprintf");
+		int status = system(cmd);
 		if (status == -1) {
 			fprintf(stderr, "Error: cannot run firejail-welcome.sh\n");
 			exit(1);
 		}
+		free(cmd);
 
 		// the last 8 bits of the status is the return value of the command executed by system()
 		// firejail-welcome.sh returns 55 if setting sysmlinks is required