1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * /proc/bootconfig - Extra boot configuration |
4 | */ |
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 | |
13 | static char *saved_boot_config; |
14 | |
15 | static int boot_config_proc_show(struct seq_file *m, void *v) |
16 | { |
17 | if (saved_boot_config) |
18 | seq_puts(m, s: 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 */ |
26 | static 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(node: leaf, buf: key, XBC_KEYLEN_MAX); |
40 | if (ret < 0) |
41 | break; |
42 | ret = snprintf(buf: dst, rest(dst, end), fmt: "%s = " , key); |
43 | if (ret < 0) |
44 | break; |
45 | dst += ret; |
46 | vnode = xbc_node_get_child(node: leaf); |
47 | if (vnode) { |
48 | xbc_array_for_each_value(vnode, val) { |
49 | if (strchr(val, '"')) |
50 | q = '\''; |
51 | else |
52 | q = '"'; |
53 | ret = snprintf(buf: dst, rest(dst, end), fmt: "%c%s%c%s" , |
54 | q, val, q, xbc_node_is_array(node: vnode) ? ", " : "\n" ); |
55 | if (ret < 0) |
56 | goto out; |
57 | dst += ret; |
58 | } |
59 | } else { |
60 | ret = snprintf(buf: dst, rest(dst, end), fmt: "\"\"\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(buf: dst, rest(dst, end), fmt: "# Parameters from bootloader:\n# %s\n" , |
68 | boot_command_line); |
69 | if (ret > 0) |
70 | dst += ret; |
71 | } |
72 | out: |
73 | kfree(objp: key); |
74 | |
75 | return ret < 0 ? ret : dst - (end - size); |
76 | } |
77 | |
78 | static int __init proc_boot_config_init(void) |
79 | { |
80 | int len; |
81 | |
82 | len = copy_xbc_key_value_list(NULL, size: 0); |
83 | if (len < 0) |
84 | return len; |
85 | |
86 | if (len > 0) { |
87 | saved_boot_config = kzalloc(size: len + 1, GFP_KERNEL); |
88 | if (!saved_boot_config) |
89 | return -ENOMEM; |
90 | |
91 | len = copy_xbc_key_value_list(dst: saved_boot_config, size: len + 1); |
92 | if (len < 0) { |
93 | kfree(objp: 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 | } |
102 | fs_initcall(proc_boot_config_init); |
103 | |