103 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * /proc/bootconfig - Extra boot configuration4 */5#include <linux/fs.h>6#include <linux/init.h>7#include <linux/printk.h>8#include <linux/proc_fs.h>9#include <linux/seq_file.h>10#include <linux/bootconfig.h>11#include <linux/slab.h>12 13static char *saved_boot_config;14 15static int boot_config_proc_show(struct seq_file *m, void *v)16{17 if (saved_boot_config)18 seq_puts(m, saved_boot_config);19 return 0;20}21 22/* Rest size of buffer */23#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)24 25/* Return the needed total length if @size is 0 */26static int __init copy_xbc_key_value_list(char *dst, size_t size)27{28 struct xbc_node *leaf, *vnode;29 char *key, *end = dst + size;30 const char *val;31 char q;32 int ret = 0;33 34 key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);35 if (!key)36 return -ENOMEM;37 38 xbc_for_each_key_value(leaf, val) {39 ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);40 if (ret < 0)41 break;42 ret = snprintf(dst, rest(dst, end), "%s = ", key);43 if (ret < 0)44 break;45 dst += ret;46 vnode = xbc_node_get_child(leaf);47 if (vnode) {48 xbc_array_for_each_value(vnode, val) {49 if (strchr(val, '"'))50 q = '\'';51 else52 q = '"';53 ret = snprintf(dst, rest(dst, end), "%c%s%c%s",54 q, val, q, xbc_node_is_array(vnode) ? ", " : "\n");55 if (ret < 0)56 goto out;57 dst += ret;58 }59 } else {60 ret = snprintf(dst, rest(dst, end), "\"\"\n");61 if (ret < 0)62 break;63 dst += ret;64 }65 }66 if (cmdline_has_extra_options() && ret >= 0 && boot_command_line[0]) {67 ret = snprintf(dst, rest(dst, end), "# Parameters from bootloader:\n# %s\n",68 boot_command_line);69 if (ret > 0)70 dst += ret;71 }72out:73 kfree(key);74 75 return ret < 0 ? ret : dst - (end - size);76}77 78static int __init proc_boot_config_init(void)79{80 int len;81 82 len = copy_xbc_key_value_list(NULL, 0);83 if (len < 0)84 return len;85 86 if (len > 0) {87 saved_boot_config = kzalloc(len + 1, GFP_KERNEL);88 if (!saved_boot_config)89 return -ENOMEM;90 91 len = copy_xbc_key_value_list(saved_boot_config, len + 1);92 if (len < 0) {93 kfree(saved_boot_config);94 return len;95 }96 }97 98 proc_create_single("bootconfig", 0, NULL, boot_config_proc_show);99 100 return 0;101}102fs_initcall(proc_boot_config_init);103