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, 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 36 xbc_for_each_key_value(leaf, val) { 37 ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX); 38 if (ret < 0) 39 break; 40 ret = snprintf(dst, rest(dst, end), "%s = ", key); 41 if (ret < 0) 42 break; 43 dst += ret; 44 vnode = xbc_node_get_child(leaf); 45 if (vnode) { 46 xbc_array_for_each_value(vnode, val) { 47 if (strchr(val, '"')) 48 q = '\''; 49 else 50 q = '"'; 51 ret = snprintf(dst, rest(dst, end), "%c%s%c%s", 52 q, val, q, xbc_node_is_array(vnode) ? ", " : "\n"); 53 if (ret < 0) 54 goto out; 55 dst += ret; 56 } 57 } else { 58 ret = snprintf(dst, rest(dst, end), "\"\"\n"); 59 if (ret < 0) 60 break; 61 dst += ret; 62 } 63 } 64 out: 65 kfree(key); 66 67 return ret < 0 ? ret : dst - (end - size); 68 } 69 70 static int __init proc_boot_config_init(void) 71 { 72 int len; 73 74 len = copy_xbc_key_value_list(NULL, 0); 75 if (len < 0) 76 return len; 77 78 if (len > 0) { 79 saved_boot_config = kzalloc(len + 1, GFP_KERNEL); 80 if (!saved_boot_config) 81 return -ENOMEM; 82 83 len = copy_xbc_key_value_list(saved_boot_config, len + 1); 84 if (len < 0) { 85 kfree(saved_boot_config); 86 return len; 87 } 88 } 89 90 proc_create_single("bootconfig", 0, NULL, boot_config_proc_show); 91 92 return 0; 93 } 94 fs_initcall(proc_boot_config_init); 95