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fs/proc/bootconfig.c
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c1a3c3601
proc: bootconfig:...
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// 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;
const char *val;
char *key, *end = dst + size;
int ret = 0;
key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);
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_node_is_array(vnode)) {
xbc_array_for_each_value(vnode, val) {
ret = snprintf(dst, rest(dst, end), "\"%s\"%s",
val, vnode->next ? ", " : "
");
if (ret < 0)
goto out;
dst += ret;
}
} else {
ret = snprintf(dst, rest(dst, end), "\"%s\"
", val);
if (ret < 0)
break;
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);
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