Parse /kboot.conf

If there's a kboot.conf, prase it after the command line args are
parsed. It's not always easy to get all the right command line args
depending on the environment. Allow an escape hatch. While we can't do
everything one might like in this file, we can do enough.

Sponsored by:		Netflix

stand/kboot/main.c

@@ -195,6 +195,31 @@ has_acpi(void)
 	return rsdp != 0;
 }
 
+static void
+parse_file(const char *fn)
+{
+	struct stat st;
+	int fd = -1;
+	char *env = NULL;
+
+	if (stat(fn, &st) != 0)
+		return;
+	fd = open(fn, O_RDONLY);
+	if (fd == -1)
+		return;
+	env = malloc(st.st_size + 1);
+	if (env == NULL)
+		goto out;
+	if (read(fd, env, st.st_size) != st.st_size)
+		goto out;
+	env[st.st_size] = '\0';
+	boot_parse_cmdline(env);
+out:
+	free(env);
+	close(fd);
+}
+
+
 int
 main(int argc, const char **argv)
 {
@@ -221,6 +246,8 @@ main(int argc, const char **argv)
 	/* Parse the command line args -- ignoring for now the console selection */
 	parse_args(argc, argv);
 
+	parse_file("host:/kboot.conf");
+
 	/*
 	 * Set up console.
 	 */