// SPDX-License-Identifier: GPL-2.0

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/highmem.h>
#include <linux/kdev_t.h>
#include <linux/sysfs.h>
#include <linux/kobject.h>
#include <linux/mutex.h>

#include "dm-verity-debug.h"

#define ALTA_BUF_SIZE 4096

static DEFINE_MUTEX(alta_lock);

char *alta_buf;
size_t *alta_offset, alta_size;

struct kobject *kobj_ref;

void set_print_buf(char *buf, size_t *offset, size_t size)
{
	alta_buf = buf;
	alta_offset = offset;
	alta_size = size;

	*alta_offset = 0;
}

void alta_print(const char *fmt, ...)
{
	size_t offset = *alta_offset;
	va_list aptr;

	va_start(aptr, fmt);
	*alta_offset += vscnprintf(alta_buf + offset, (size_t)alta_size - offset, fmt, aptr);
	va_end(aptr);
}

static void show_fc_blks_list(void)
{
	int i = 0;

	if (empty_b_info())
		return;

	if (get_fec_correct_blks() == 0) {
		alta_print("\n");
		return;
	}

	if (get_fec_correct_blks() >= (long long)MAX_FC_BLKS_LIST) {
		alta_print(",\"fc_dev\":\"%s\"", b_info->dev_name[b_info->list_idx]);
		alta_print(",\"fc_blk\":\"%llu\"", b_info->fc_blks_list[b_info->list_idx]);
		i = (b_info->list_idx + 1) % MAX_FC_BLKS_LIST;
	}

	for (; i != b_info->list_idx; i = (i + 1) % MAX_FC_BLKS_LIST) {
		alta_print(",\"fc_dev\":\"%s\"", b_info->dev_name[i]);
		alta_print(",\"fc_blk\":\"%llu\"", b_info->fc_blks_list[i]);
	}
	alta_print("\n");
}

static void show_dmv_ctr_list(void)
{
	int i = 0, ctr_cnt = get_dmv_ctr_cnt();

	if (empty_b_info())
		return;

	alta_print(",\"dmv_dev_cnt\":\"%d\"", ctr_cnt);

	for (; i < ctr_cnt; i++)
		alta_print(",\"dmv_dev\":\"%s\"", b_info->dmv_ctr_list[i]);
}

static void show_blks_cnt(void)
{
	int i, foc = get_fec_off_cnt();

	if (empty_b_info())
		return;

	alta_print("\"total_blks\":\"%llu\"", get_total_blks());
	alta_print(",\"skipped_blks\":\"%llu\"", get_skipped_blks());
	alta_print(",\"corrupted_blks\":\"%llu\"", get_corrupted_blks());
	alta_print(",\"fec_correct_blks\":\"%llu\"", get_fec_correct_blks());

	if (foc > 0) {
		alta_print(",\"fec_off_cnt\":\"%d\"", foc);
		for (i = 0; i < foc; i++)
			alta_print(",\"fec_off_dev\":\"%s\"", b_info->fec_off_list[i]);
	}
}

ssize_t alta_bigdata_read(struct file *filep, char __user *buf, size_t size, loff_t *offset)
{
	ssize_t ret;
	size_t proc_offset = 0;
	char *proc_buf = kzalloc(ALTA_BUF_SIZE, GFP_KERNEL);

	if (!proc_buf)
		return -ENOMEM;

	mutex_lock(&alta_lock);
	set_print_buf(proc_buf, &proc_offset, ALTA_BUF_SIZE);

	/* Print DMV info */
	if (empty_b_info()) {
		alta_print("\"ERROR\":\"b_info_empty\"\n");
	} else {
		show_blks_cnt();
		show_dmv_ctr_list();
		show_fc_blks_list();
	}
	mutex_unlock(&alta_lock);

	ret = simple_read_from_buffer(buf, size, offset, proc_buf, proc_offset);
	kfree(proc_buf);

	return ret;
}

static ssize_t sysfs_show(struct kobject *kobj,
		struct kobj_attribute *attr, char *buf)
{
	size_t sysfs_offset;

	mutex_lock(&alta_lock);
	set_print_buf(buf, &sysfs_offset, PAGE_SIZE);

	/* Print DMV info */
	if (empty_b_info()) {
		alta_print("\"ERROR\":\"b_info_empty\"\n");
	} else {
		show_blks_cnt();
		show_dmv_ctr_list();
		show_fc_blks_list();
	}
	mutex_unlock(&alta_lock);

	return sysfs_offset;
}

static const struct proc_ops alta_proc_ops = {
	.proc_read = alta_bigdata_read,
};

struct kobj_attribute alta_attr = __ATTR(dmv_info, 0444, sysfs_show, NULL);

static int __init alta_bigdata_init(void)
{
	if (proc_create("alta_bigdata", 0444, NULL, &alta_proc_ops) == NULL) {
		printk(KERN_ERR "alta_bigdata: Error creating proc entry");
		goto bad_proc;
	}

	/*Creating a directory in /sys/kernel/ */
	kobj_ref = kobject_create_and_add("alta_bigdata", kernel_kobj);

	/*Creating sysfs file for dmv_info*/
	if (sysfs_create_file(kobj_ref, &alta_attr.attr)) {
		printk(KERN_INFO "alta_bigdata: Cannot create sysfs file......\n");
		goto bad_sysfs;
	}

	pr_info("alta_bigdata : create /proc/alta_bigdata");
	return 0;

bad_sysfs:
	kobject_put(kobj_ref);
	sysfs_remove_file(kernel_kobj, &alta_attr.attr);

bad_proc:
	free_b_info();
	remove_proc_entry("alta_bigdata", NULL);

	return -1;
}

static void __exit alta_bigdata_exit(void)
{
	kobject_put(kobj_ref);
	sysfs_remove_file(kernel_kobj, &alta_attr.attr);

	free_b_info();
	remove_proc_entry("alta_bigdata", NULL);
}
module_init(alta_bigdata_init);
module_exit(alta_bigdata_exit);