+static int build_environment(
+ ExecContext *c,
+ unsigned n_fds,
+ usec_t watchdog_usec,
+ const char *home,
+ const char *username,
+ const char *shell,
+ char ***ret) {
+
+ _cleanup_strv_free_ char **our_env = NULL;
+ unsigned n_env = 0;
+ char *x;
+
+ assert(c);
+ assert(ret);
+
+ our_env = new0(char*, 10);
+ if (!our_env)
+ return -ENOMEM;
+
+ if (n_fds > 0) {
+ if (asprintf(&x, "LISTEN_PID="PID_FMT, getpid()) < 0)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+
+ if (asprintf(&x, "LISTEN_FDS=%u", n_fds) < 0)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
+ if (watchdog_usec > 0) {
+ if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid()) < 0)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+
+ if (asprintf(&x, "WATCHDOG_USEC=%llu", (unsigned long long) watchdog_usec) < 0)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
+ if (home) {
+ x = strappend("HOME=", home);
+ if (!x)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
+ if (username) {
+ x = strappend("LOGNAME=", username);
+ if (!x)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+
+ x = strappend("USER=", username);
+ if (!x)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
+ if (shell) {
+ x = strappend("SHELL=", shell);
+ if (!x)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
+ if (is_terminal_input(c->std_input) ||
+ c->std_output == EXEC_OUTPUT_TTY ||
+ c->std_error == EXEC_OUTPUT_TTY ||
+ c->tty_path) {
+
+ x = strdup(default_term_for_tty(tty_path(c)));
+ if (!x)
+ return -ENOMEM;
+ our_env[n_env++] = x;
+ }
+
+ our_env[n_env++] = NULL;
+ assert(n_env <= 10);
+
+ *ret = our_env;
+ our_env = NULL;
+
+ return 0;
+}
+