forked from luck/tmp_suning_uos_patched
c1a3c36017
Add /proc/bootconfig which shows the list of key-value pairs in boot config. Since after boot, all boot configs and tree are removed, this interface just keep a copy of key-value pairs in text. Link: http://lkml.kernel.org/r/157867225967.17873.12155805787236073787.stgit@devnote2 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
90 lines
1.9 KiB
C
90 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* /proc/bootconfig - Extra boot configuration
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/printk.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/bootconfig.h>
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#include <linux/slab.h>
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static char *saved_boot_config;
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static int boot_config_proc_show(struct seq_file *m, void *v)
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{
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if (saved_boot_config)
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seq_puts(m, saved_boot_config);
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return 0;
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}
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/* Rest size of buffer */
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#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
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/* Return the needed total length if @size is 0 */
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static int __init copy_xbc_key_value_list(char *dst, size_t size)
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{
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struct xbc_node *leaf, *vnode;
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const char *val;
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char *key, *end = dst + size;
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int ret = 0;
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key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);
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xbc_for_each_key_value(leaf, val) {
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ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);
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if (ret < 0)
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break;
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ret = snprintf(dst, rest(dst, end), "%s = ", key);
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if (ret < 0)
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break;
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dst += ret;
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vnode = xbc_node_get_child(leaf);
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if (vnode && xbc_node_is_array(vnode)) {
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xbc_array_for_each_value(vnode, val) {
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ret = snprintf(dst, rest(dst, end), "\"%s\"%s",
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val, vnode->next ? ", " : "\n");
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if (ret < 0)
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goto out;
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dst += ret;
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}
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} else {
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ret = snprintf(dst, rest(dst, end), "\"%s\"\n", val);
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if (ret < 0)
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break;
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dst += ret;
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}
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}
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out:
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kfree(key);
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return ret < 0 ? ret : dst - (end - size);
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}
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static int __init proc_boot_config_init(void)
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{
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int len;
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len = copy_xbc_key_value_list(NULL, 0);
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if (len < 0)
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return len;
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if (len > 0) {
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saved_boot_config = kzalloc(len + 1, GFP_KERNEL);
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if (!saved_boot_config)
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return -ENOMEM;
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len = copy_xbc_key_value_list(saved_boot_config, len + 1);
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if (len < 0) {
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kfree(saved_boot_config);
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return len;
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}
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}
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proc_create_single("bootconfig", 0, NULL, boot_config_proc_show);
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return 0;
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}
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fs_initcall(proc_boot_config_init);
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