// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/net/sunrpc/sysctl.c
 *
 * Sysctl interface to sunrpc module.
 *
 * I would prefer to register the sunrpc table below sys/net, but that's
 * impossible at the moment.
 */

#include <linux/types.h>
#include <linux/linkage.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/sysctl.h>
#include <linux/module.h>

#include <linux/uaccess.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc_xprt.h>

#include "netns.h"

/*
 * Declare the debug flags here
 */
unsigned int    rpc_debug;
EXPORT_SYMBOL_GPL(rpc_debug);

unsigned int    nfs_debug;
EXPORT_SYMBOL_GPL(nfs_debug);

unsigned int    nfsd_debug;
EXPORT_SYMBOL_GPL(nfsd_debug);

unsigned int    nlm_debug;
EXPORT_SYMBOL_GPL(nlm_debug);

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)

static int proc_do_xprt(const struct ctl_table *table, int write,
                        void *buffer, size_t *lenp, loff_t *ppos)
{
        char tmpbuf[256];
        ssize_t len;

        if (write || *ppos) {
                *lenp = 0;
                return 0;
        }
        len = svc_print_xprts(tmpbuf, sizeof(tmpbuf));
        len = memory_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);

        if (len < 0) {
                *lenp = 0;
                return -EINVAL;
        }
        *lenp = len;
        return 0;
}

static int
proc_dodebug(const struct ctl_table *table, int write, void *buffer, size_t *lenp,
             loff_t *ppos)
{
        char            tmpbuf[20], *s = NULL;
        char *p;
        unsigned int    value;
        size_t          left, len;

        if ((*ppos && !write) || !*lenp) {
                *lenp = 0;
                return 0;
        }

        left = *lenp;

        if (write) {
                p = buffer;
                while (left && isspace(*p)) {
                        left--;
                        p++;
                }
                if (!left)
                        goto done;

                if (left > sizeof(tmpbuf) - 1)
                        return -EINVAL;
                memcpy(tmpbuf, p, left);
                tmpbuf[left] = '\0';

                value = simple_strtol(tmpbuf, &s, 0);
                if (s) {
                        left -= (s - tmpbuf);
                        if (left && !isspace(*s))
                                return -EINVAL;
                        while (left && isspace(*s)) {
                                left--;
                                s++;
                        }
                } else
                        left = 0;
                *(unsigned int *) table->data = value;
                /* Display the RPC tasks on writing to rpc_debug */
                if (strcmp(table->procname, "rpc_debug") == 0)
                        rpc_show_tasks(&init_net);
        } else {
                len = sprintf(tmpbuf, "0x%04x", *(unsigned int *) table->data);
                if (len > left)
                        len = left;
                memcpy(buffer, tmpbuf, len);
                if ((left -= len) > 0) {
                        *((char *)buffer + len) = '\n';
                        left--;
                }
        }

done:
        *lenp -= left;
        *ppos += *lenp;
        return 0;
}

static struct ctl_table_header *sunrpc_table_header;

static struct ctl_table debug_table[] = {
        {
                .procname       = "rpc_debug",
                .data           = &rpc_debug,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dodebug
        },
        {
                .procname       = "nfs_debug",
                .data           = &nfs_debug,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dodebug
        },
        {
                .procname       = "nfsd_debug",
                .data           = &nfsd_debug,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dodebug
        },
        {
                .procname       = "nlm_debug",
                .data           = &nlm_debug,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dodebug
        },
        {
                .procname       = "transports",
                .maxlen         = 256,
                .mode           = 0444,
                .proc_handler   = proc_do_xprt,
        },
};

void
rpc_register_sysctl(void)
{
        if (!sunrpc_table_header)
                sunrpc_table_header = register_sysctl("sunrpc", debug_table);
}

void
rpc_unregister_sysctl(void)
{
        if (sunrpc_table_header) {
                unregister_sysctl_table(sunrpc_table_header);
                sunrpc_table_header = NULL;
        }
}
#endif