// SPDX-License-Identifier: GPL-2.0/* * /proc/bootconfig - Extra boot configuration */#include <linux/fs.h>#include <linux/init.h>#include <linux/printk.h>#include <linux/proc_fs.h>#include <linux/seq_file.h>#include <linux/bootconfig.h>#include <linux/slab.h> static char *saved_boot_config; static int boot_config_proc_show(struct seq_file *m, void *v){	if (saved_boot_config)		seq_puts(m, saved_boot_config);	return 0;} /* Rest size of buffer */#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0) /* Return the needed total length if @size is 0 */static int __init copy_xbc_key_value_list(char *dst, size_t size){	struct xbc_node *leaf, *vnode;	char *key, *end = dst + size;	const char *val;	char q;	int ret = 0; 	key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);	if (!key)		return -ENOMEM; 	xbc_for_each_key_value(leaf, val) {		ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);		if (ret < 0)			break;		ret = snprintf(dst, rest(dst, end), "%s = ", key);		if (ret < 0)			break;		dst += ret;		vnode = xbc_node_get_child(leaf);		if (vnode) {			xbc_array_for_each_value(vnode, val) {				if (strchr(val, '"'))					q = '\'';				else					q = '"';				ret = snprintf(dst, rest(dst, end), "%c%s%c%s",					q, val, q, xbc_node_is_array(vnode) ? ", " : "\n");				if (ret < 0)					goto out;				dst += ret;			}		} else {			ret = snprintf(dst, rest(dst, end), "\"\"\n");			if (ret < 0)				break;			dst += ret;		}	}	if (cmdline_has_extra_options() && ret >= 0 && boot_command_line[0]) {		ret = snprintf(dst, rest(dst, end), "# Parameters from bootloader:\n# %s\n",			       boot_command_line);		if (ret > 0)			dst += ret;	}out:	kfree(key); 	return ret < 0 ? ret : dst - (end - size);} static int __init proc_boot_config_init(void){	int len; 	len = copy_xbc_key_value_list(NULL, 0);	if (len < 0)		return len; 	if (len > 0) {		saved_boot_config = kzalloc(len + 1, GFP_KERNEL);		if (!saved_boot_config)			return -ENOMEM; 		len = copy_xbc_key_value_list(saved_boot_config, len + 1);		if (len < 0) {			kfree(saved_boot_config);			return len;		}	} 	proc_create_single("bootconfig", 0, NULL, boot_config_proc_show); 	return 0;}fs_initcall(proc_boot_config_init);