diff --git a/cmd.c b/cmd.c
index 6c4a06f4..5333a023 100644
--- a/cmd.c
+++ b/cmd.c
@@ -356,7 +356,7 @@ cmd_current_session(struct cmd_ctx *ctx)
 	}
 
 	/* Use the session from the TMUX environment variable. */
-	if (data != NULL && data->pid == getpid()) {
+	if (data != NULL && data->pid == getpid() && data->idx != -1) {
 		s = session_find_by_index(data->idx);
 		if (s != NULL)
 			return (s);
diff --git a/job.c b/job.c
index c7181964..ce7961a1 100644
--- a/job.c
+++ b/job.c
@@ -137,7 +137,8 @@ job_free(struct job *job)
 int
 job_run(struct job *job)
 {
-	int	nullfd, out[2];
+	struct environ	env;
+	int		nullfd, out[2];
 
 	if (job->fd != -1 || job->pid != -1)
 		return (0);
@@ -145,13 +146,19 @@ job_run(struct job *job)
 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, out) != 0)
 		return (-1);
 
+	environ_init(&env);
+	environ_copy(&global_environ, &env);
+	server_fill_environ(NULL, &env);
+
 	switch (job->pid = fork()) {
 	case -1:
+		environ_free(&env);
 		return (-1);
 	case 0:		/* child */
 		clear_signals(1);
 
-		environ_push(&global_environ);
+		environ_push(&env);
+		environ_free(&env);
 
 		if (dup2(out[1], STDOUT_FILENO) == -1)
 			fatal("dup2 failed");
@@ -174,6 +181,7 @@ job_run(struct job *job)
 		execl(_PATH_BSHELL, "sh", "-c", job->cmd, (char *) NULL);
 		fatal("execl failed");
 	default:	/* parent */
+		environ_free(&env);
 		close(out[1]);
 
 		job->fd = out[0];
diff --git a/server-fn.c b/server-fn.c
index 7064c1ed..002d56ac 100644
--- a/server-fn.c
+++ b/server-fn.c
@@ -30,14 +30,20 @@ void		server_callback_identify(int, short, void *);
 void
 server_fill_environ(struct session *s, struct environ *env)
 {
-	char	tmuxvar[MAXPATHLEN], *term;
+	char	var[MAXPATHLEN], *term;
+	u_int	idx;
+	long	pid;
 
-	xsnprintf(tmuxvar, sizeof tmuxvar,
-	    "%s,%ld,%u", socket_path, (long) getpid(), s->idx);
-	environ_set(env, "TMUX", tmuxvar);
+	if (s != NULL) {
+		term = options_get_string(&s->options, "default-terminal");
+		environ_set(env, "TERM", term);
 
-	term = options_get_string(&s->options, "default-terminal");
-	environ_set(env, "TERM", term);
+		idx = s->idx;
+	} else
+		idx = -1;
+	pid = getpid();
+	xsnprintf(var, sizeof var, "%s,%ld,%d", socket_path, pid, idx);
+	environ_set(env, "TMUX", var);
 }
 
 void
diff --git a/tmux.c b/tmux.c
index 0225f5f6..31070f00 100644
--- a/tmux.c
+++ b/tmux.c
@@ -48,8 +48,8 @@ time_t		 start_time;
 char		 socket_path[MAXPATHLEN];
 int		 login_shell;
 char		*environ_path;
-pid_t		 environ_pid;
-u_int		 environ_idx;
+pid_t		 environ_pid = -1;
+int		 environ_idx = -1;
 
 __dead void	 usage(void);
 void	 	 parseenvironment(void);
@@ -125,45 +125,18 @@ areshell(const char *shell)
 void
 parseenvironment(void)
 {
-	char		*env, *path_pid, *pid_idx, buf[256];
-	size_t		 len;
-	const char	*errstr;
-	long long	 ll;
+	char	*env, path[256];
+	long	 pid;
+	int	 idx;
 
-	environ_pid = -1;
 	if ((env = getenv("TMUX")) == NULL)
 		return;
 
-	if ((path_pid = strchr(env, ',')) == NULL || path_pid == env)
+	if (sscanf(env, "%255s,%ld,%d", path, &pid, &idx) != 3)
 		return;
-	if ((pid_idx = strchr(path_pid + 1, ',')) == NULL)
-		return;
-	if ((pid_idx == path_pid + 1 || pid_idx[1] == '\0'))
-		return;
-
-	/* path */
-	len = path_pid - env;
-	environ_path = xmalloc(len + 1);
-	memcpy(environ_path, env, len);
-	environ_path[len] = '\0';
-
-	/* pid */
-	len = pid_idx - path_pid - 1;
-	if (len > (sizeof buf) - 1)
-		return;
-	memcpy(buf, path_pid + 1, len);
-	buf[len] = '\0';
-
-	ll = strtonum(buf, 0, LONG_MAX, &errstr);
-	if (errstr != NULL)
-		return;
-	environ_pid = ll;
-
-	/* idx */
-	ll = strtonum(pid_idx + 1, 0, UINT_MAX, &errstr);
-	if (errstr != NULL)
-		return;
-	environ_idx = ll;
+	environ_path = xstrdup(path);
+	environ_pid = pid;
+	environ_idx = idx;
 }
 
 char *
diff --git a/tmux.h b/tmux.h
index 4eab285c..f6a45d33 100644
--- a/tmux.h
+++ b/tmux.h
@@ -383,8 +383,8 @@ enum msgtype {
  * Don't forget to bump PROTOCOL_VERSION if any of these change!
  */
 struct msg_command_data {
-	pid_t		pid;			/* pid from $TMUX or -1 */
-	u_int		idx;			/* index from $TMUX */
+	pid_t		pid;	/* PID from $TMUX or -1 */
+	int		idx;	/* index from $TMUX or -1 */
 
 	int		argc;
 	char		argv[COMMAND_LENGTH];
@@ -1301,7 +1301,7 @@ extern char	 socket_path[MAXPATHLEN];
 extern int	 login_shell;
 extern char	*environ_path;
 extern pid_t	 environ_pid;
-extern u_int	 environ_idx;
+extern int	 environ_idx;
 void		 logfile(const char *);
 const char	*getshell(void);
 int		 checkshell(const char *);