// SPDX-License-Identifier: GPL-2.0-or-later
/* /proc interface for AFS
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include "internal.h"

struct afs_vl_seq_net_private {
        struct seq_net_private          seq;    /* Must be first */
        struct afs_vlserver_list        *vllist;
};

static inline struct afs_net *afs_seq2net(struct seq_file *m)
{
        return afs_net(seq_file_net(m));
}

static inline struct afs_net *afs_seq2net_single(struct seq_file *m)
{
        return afs_net(seq_file_single_net(m));
}

/*
 * Display the list of cells known to the namespace.
 */
static int afs_proc_cells_show(struct seq_file *m, void *v)
{
        struct afs_vlserver_list *vllist;
        struct afs_cell *cell;

        if (v == SEQ_START_TOKEN) {
                /* display header on line 1 */
                seq_puts(m, "USE    TTL SV NAME\n");
                return 0;
        }

        cell = list_entry(v, struct afs_cell, proc_link);
        vllist = rcu_dereference(cell->vl_servers);

        /* display one cell per line on subsequent lines */
        seq_printf(m, "%3u %6lld %2u %s\n",
                   atomic_read(&cell->usage),
                   cell->dns_expiry - ktime_get_real_seconds(),
                   vllist->nr_servers,
                   cell->name);
        return 0;
}

static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
        __acquires(rcu)
{
        rcu_read_lock();
        return seq_hlist_start_head_rcu(&afs_seq2net(m)->proc_cells, *_pos);
}

static void *afs_proc_cells_next(struct seq_file *m, void *v, loff_t *pos)
{
        return seq_hlist_next_rcu(v, &afs_seq2net(m)->proc_cells, pos);
}

static void afs_proc_cells_stop(struct seq_file *m, void *v)
        __releases(rcu)
{
        rcu_read_unlock();
}

static const struct seq_operations afs_proc_cells_ops = {
        .start  = afs_proc_cells_start,
        .next   = afs_proc_cells_next,
        .stop   = afs_proc_cells_stop,
        .show   = afs_proc_cells_show,
};

/*
 * handle writes to /proc/fs/afs/cells
 * - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
 */
static int afs_proc_cells_write(struct file *file, char *buf, size_t size)
{
        struct seq_file *m = file->private_data;
        struct afs_net *net = afs_seq2net(m);
        char *name, *args;
        int ret;

        /* trim to first NL */
        name = memchr(buf, '\n', size);
        if (name)
                *name = 0;

        /* split into command, name and argslist */
        name = strchr(buf, ' ');
        if (!name)
                goto inval;
        do {
                *name++ = 0;
        } while(*name == ' ');
        if (!*name)
                goto inval;

        args = strchr(name, ' ');
        if (args) {
                do {
                        *args++ = 0;
                } while(*args == ' ');
                if (!*args)
                        goto inval;
        }

        /* determine command to perform */
        _debug("cmd=%s name=%s args=%s", buf, name, args);

        if (strcmp(buf, "add") == 0) {
                struct afs_cell *cell;

                cell = afs_lookup_cell(net, name, strlen(name), args, true);
                if (IS_ERR(cell)) {
                        ret = PTR_ERR(cell);
                        goto done;
                }

                if (test_and_set_bit(AFS_CELL_FL_NO_GC, &cell->flags))
                        afs_put_cell(net, cell);
        } else {
                goto inval;
        }

        ret = 0;

done:
        _leave(" = %d", ret);
        return ret;

inval:
        ret = -EINVAL;
        printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
        goto done;
}

/*
 * Display the name of the current workstation cell.
 */
static int afs_proc_rootcell_show(struct seq_file *m, void *v)
{
        struct afs_cell *cell;
        struct afs_net *net;

        net = afs_seq2net_single(m);
        if (rcu_access_pointer(net->ws_cell)) {
                rcu_read_lock();
                cell = rcu_dereference(net->ws_cell);
                if (cell)
                        seq_printf(m, "%s\n", cell->name);
                rcu_read_unlock();
        }
        return 0;
}

/*
 * Set the current workstation cell and optionally supply its list of volume
 * location servers.
 *
 *      echo "cell.name:192.168.231.14" >/proc/fs/afs/rootcell
 */
static int afs_proc_rootcell_write(struct file *file, char *buf, size_t size)
{
        struct seq_file *m = file->private_data;
        struct afs_net *net = afs_seq2net_single(m);
        char *s;
        int ret;

        ret = -EINVAL;
        if (buf[0] == '.')
                goto out;
        if (memchr(buf, '/', size))
                goto out;

        /* trim to first NL */
        s = memchr(buf, '\n', size);
        if (s)
                *s = 0;

        /* determine command to perform */
        _debug("rootcell=%s", buf);

        ret = afs_cell_init(net, buf);

out:
        _leave(" = %d", ret);
        return ret;
}

static const char afs_vol_types[3][3] = {
        [AFSVL_RWVOL]   = "RW",
        [AFSVL_ROVOL]   = "RO",
        [AFSVL_BACKVOL] = "BK",
};

/*
 * Display the list of volumes known to a cell.
 */
static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
{
        struct afs_cell *cell = PDE_DATA(file_inode(m->file));
        struct afs_volume *vol = list_entry(v, struct afs_volume, proc_link);

        /* Display header on line 1 */
        if (v == &cell->proc_volumes) {
                seq_puts(m, "USE VID      TY\n");
                return 0;
        }

        seq_printf(m, "%3d %08llx %s\n",
                   atomic_read(&vol->usage), vol->vid,
                   afs_vol_types[vol->type]);

        return 0;
}

static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
        __acquires(cell->proc_lock)
{
        struct afs_cell *cell = PDE_DATA(file_inode(m->file));

        read_lock(&cell->proc_lock);
        return seq_list_start_head(&cell->proc_volumes, *_pos);
}

static void *afs_proc_cell_volumes_next(struct seq_file *m, void *v,
                                        loff_t *_pos)
{
        struct afs_cell *cell = PDE_DATA(file_inode(m->file));

        return seq_list_next(v, &cell->proc_volumes, _pos);
}

static void afs_proc_cell_volumes_stop(struct seq_file *m, void *v)
        __releases(cell->proc_lock)
{
        struct afs_cell *cell = PDE_DATA(file_inode(m->file));

        read_unlock(&cell->proc_lock);
}

static const struct seq_operations afs_proc_cell_volumes_ops = {
        .start  = afs_proc_cell_volumes_start,
        .next   = afs_proc_cell_volumes_next,
        .stop   = afs_proc_cell_volumes_stop,
        .show   = afs_proc_cell_volumes_show,
};

static const char *const dns_record_sources[NR__dns_record_source + 1] = {
        [DNS_RECORD_UNAVAILABLE]        = "unav",
        [DNS_RECORD_FROM_CONFIG]        = "cfg",
        [DNS_RECORD_FROM_DNS_A]         = "A",
        [DNS_RECORD_FROM_DNS_AFSDB]     = "AFSDB",
        [DNS_RECORD_FROM_DNS_SRV]       = "SRV",
        [DNS_RECORD_FROM_NSS]           = "nss",
        [NR__dns_record_source]         = "[weird]"
};

static const char *const dns_lookup_statuses[NR__dns_lookup_status + 1] = {
        [DNS_LOOKUP_NOT_DONE]           = "no-lookup",
        [DNS_LOOKUP_GOOD]               = "good",
        [DNS_LOOKUP_GOOD_WITH_BAD]      = "good/bad",
        [DNS_LOOKUP_BAD]                = "bad",
        [DNS_LOOKUP_GOT_NOT_FOUND]      = "not-found",
        [DNS_LOOKUP_GOT_LOCAL_FAILURE]  = "local-failure",
        [DNS_LOOKUP_GOT_TEMP_FAILURE]   = "temp-failure",
        [DNS_LOOKUP_GOT_NS_FAILURE]     = "ns-failure",
        [NR__dns_lookup_status]         = "[weird]"
};

/*
 * Display the list of Volume Location servers we're using for a cell.
 */
static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
{
        const struct afs_vl_seq_net_private *priv = m->private;
        const struct afs_vlserver_list *vllist = priv->vllist;
        const struct afs_vlserver_entry *entry;
        const struct afs_vlserver *vlserver;
        const struct afs_addr_list *alist;
        int i;

        if (v == SEQ_START_TOKEN) {
                seq_printf(m, "# source %s, status %s\n",
                           dns_record_sources[vllist ? vllist->source : 0],
                           dns_lookup_statuses[vllist ? vllist->status : 0]);
                return 0;
        }

        entry = v;
        vlserver = entry->server;
        alist = rcu_dereference(vlserver->addresses);

        seq_printf(m, "%s [p=%hu w=%hu s=%s,%s]:\n",
                   vlserver->name, entry->priority, entry->weight,
                   dns_record_sources[alist ? alist->source : entry->source],
                   dns_lookup_statuses[alist ? alist->status : entry->status]);
        if (alist) {
                for (i = 0; i < alist->nr_addrs; i++)
                        seq_printf(m, " %c %pISpc\n",
                                   alist->preferred == i ? '>' : '-',
                                   &alist->addrs[i].transport);
        }
        return 0;
}

static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
        __acquires(rcu)
{
        struct afs_vl_seq_net_private *priv = m->private;
        struct afs_vlserver_list *vllist;
        struct afs_cell *cell = PDE_DATA(file_inode(m->file));
        loff_t pos = *_pos;

        rcu_read_lock();

        vllist = rcu_dereference(cell->vl_servers);
        priv->vllist = vllist;

        if (pos < 0)
                *_pos = pos = 0;
        if (pos == 0)
                return SEQ_START_TOKEN;

        if (pos - 1 >= vllist->nr_servers)
                return NULL;

        return &vllist->servers[pos - 1];
}

static void *afs_proc_cell_vlservers_next(struct seq_file *m, void *v,
                                          loff_t *_pos)
{
        struct afs_vl_seq_net_private *priv = m->private;
        struct afs_vlserver_list *vllist = priv->vllist;
        loff_t pos;

        pos = *_pos;
        pos++;
        *_pos = pos;
        if (!vllist || pos - 1 >= vllist->nr_servers)
                return NULL;

        return &vllist->servers[pos - 1];
}

static void afs_proc_cell_vlservers_stop(struct seq_file *m, void *v)
        __releases(rcu)
{
        rcu_read_unlock();
}

static const struct seq_operations afs_proc_cell_vlservers_ops = {
        .start  = afs_proc_cell_vlservers_start,
        .next   = afs_proc_cell_vlservers_next,
        .stop   = afs_proc_cell_vlservers_stop,
        .show   = afs_proc_cell_vlservers_show,
};

/*
 * Display the list of fileservers we're using within a namespace.
 */
static int afs_proc_servers_show(struct seq_file *m, void *v)
{
        struct afs_server *server;
        struct afs_addr_list *alist;
        int i;

        if (v == SEQ_START_TOKEN) {
                seq_puts(m, "UUID                                 USE ADDR\n");
                return 0;
        }

        server = list_entry(v, struct afs_server, proc_link);
        alist = rcu_dereference(server->addresses);
        seq_printf(m, "%pU %3d %pISpc%s\n",
                   &server->uuid,
                   atomic_read(&server->usage),
                   &alist->addrs[0].transport,
                   alist->preferred == 0 ? "*" : "");
        for (i = 1; i < alist->nr_addrs; i++)
                seq_printf(m, "                                         %pISpc%s\n",
                           &alist->addrs[i].transport,
                           alist->preferred == i ? "*" : "");
        return 0;
}

static void *afs_proc_servers_start(struct seq_file *m, loff_t *_pos)
        __acquires(rcu)
{
        rcu_read_lock();
        return seq_hlist_start_head_rcu(&afs_seq2net(m)->fs_proc, *_pos);
}

static void *afs_proc_servers_next(struct seq_file *m, void *v, loff_t *_pos)
{
        return seq_hlist_next_rcu(v, &afs_seq2net(m)->fs_proc, _pos);
}

static void afs_proc_servers_stop(struct seq_file *m, void *v)
        __releases(rcu)
{
        rcu_read_unlock();
}

static const struct seq_operations afs_proc_servers_ops = {
        .start  = afs_proc_servers_start,
        .next   = afs_proc_servers_next,
        .stop   = afs_proc_servers_stop,
        .show   = afs_proc_servers_show,
};

/*
 * Display the list of strings that may be substituted for the @sys pathname
 * macro.
 */
static int afs_proc_sysname_show(struct seq_file *m, void *v)
{
        struct afs_net *net = afs_seq2net(m);
        struct afs_sysnames *sysnames = net->sysnames;
        unsigned int i = (unsigned long)v - 1;

        if (i < sysnames->nr)
                seq_printf(m, "%s\n", sysnames->subs[i]);
        return 0;
}

static void *afs_proc_sysname_start(struct seq_file *m, loff_t *pos)
        __acquires(&net->sysnames_lock)
{
        struct afs_net *net = afs_seq2net(m);
        struct afs_sysnames *names;

        read_lock(&net->sysnames_lock);

        names = net->sysnames;
        if (*pos >= names->nr)
                return NULL;
        return (void *)(unsigned long)(*pos + 1);
}

static void *afs_proc_sysname_next(struct seq_file *m, void *v, loff_t *pos)
{
        struct afs_net *net = afs_seq2net(m);
        struct afs_sysnames *names = net->sysnames;

        *pos += 1;
        if (*pos >= names->nr)
                return NULL;
        return (void *)(unsigned long)(*pos + 1);
}

static void afs_proc_sysname_stop(struct seq_file *m, void *v)
        __releases(&net->sysnames_lock)
{
        struct afs_net *net = afs_seq2net(m);

        read_unlock(&net->sysnames_lock);
}

static const struct seq_operations afs_proc_sysname_ops = {
        .start  = afs_proc_sysname_start,
        .next   = afs_proc_sysname_next,
        .stop   = afs_proc_sysname_stop,
        .show   = afs_proc_sysname_show,
};

/*
 * Allow the @sys substitution to be configured.
 */
static int afs_proc_sysname_write(struct file *file, char *buf, size_t size)
{
        struct afs_sysnames *sysnames, *kill;
        struct seq_file *m = file->private_data;
        struct afs_net *net = afs_seq2net(m);
        char *s, *p, *sub;
        int ret, len;

        sysnames = kzalloc(sizeof(*sysnames), GFP_KERNEL);
        if (!sysnames)
                return -ENOMEM;
        refcount_set(&sysnames->usage, 1);
        kill = sysnames;

        p = buf;
        while ((s = strsep(&p, " \t\n"))) {
                len = strlen(s);
                if (len == 0)
                        continue;
                ret = -ENAMETOOLONG;
                if (len >= AFSNAMEMAX)
                        goto error;

                if (len >= 4 &&
                    s[len - 4] == '@' &&
                    s[len - 3] == 's' &&
                    s[len - 2] == 'y' &&
                    s[len - 1] == 's')
                        /* Protect against recursion */
                        goto invalid;

                if (s[0] == '.' &&
                    (len < 2 || (len == 2 && s[1] == '.')))
                        goto invalid;

                if (memchr(s, '/', len))
                        goto invalid;

                ret = -EFBIG;
                if (sysnames->nr >= AFS_NR_SYSNAME)
                        goto out;

                if (strcmp(s, afs_init_sysname) == 0) {
                        sub = (char *)afs_init_sysname;
                } else {
                        ret = -ENOMEM;
                        sub = kmemdup(s, len + 1, GFP_KERNEL);
                        if (!sub)
                                goto out;
                }

                sysnames->subs[sysnames->nr] = sub;
                sysnames->nr++;
        }

        if (sysnames->nr == 0) {
                sysnames->subs[0] = sysnames->blank;
                sysnames->nr++;
        }

        write_lock(&net->sysnames_lock);
        kill = net->sysnames;
        net->sysnames = sysnames;
        write_unlock(&net->sysnames_lock);
        ret = 0;
out:
        afs_put_sysnames(kill);
        return ret;

invalid:
        ret = -EINVAL;
error:
        goto out;
}

void afs_put_sysnames(struct afs_sysnames *sysnames)
{
        int i;

        if (sysnames && refcount_dec_and_test(&sysnames->usage)) {
                for (i = 0; i < sysnames->nr; i++)
                        if (sysnames->subs[i] != afs_init_sysname &&
                            sysnames->subs[i] != sysnames->blank)
                                kfree(sysnames->subs[i]);
        }
}

/*
 * Display general per-net namespace statistics
 */
static int afs_proc_stats_show(struct seq_file *m, void *v)
{
        struct afs_net *net = afs_seq2net_single(m);

        seq_puts(m, "kAFS statistics\n");

        seq_printf(m, "dir-mgmt: look=%u reval=%u inval=%u relpg=%u\n",
                   atomic_read(&net->n_lookup),
                   atomic_read(&net->n_reval),
                   atomic_read(&net->n_inval),
                   atomic_read(&net->n_relpg));

        seq_printf(m, "dir-data: rdpg=%u\n",
                   atomic_read(&net->n_read_dir));

        seq_printf(m, "dir-edit: cr=%u rm=%u\n",
                   atomic_read(&net->n_dir_cr),
                   atomic_read(&net->n_dir_rm));

        seq_printf(m, "file-rd : n=%u nb=%lu\n",
                   atomic_read(&net->n_fetches),
                   atomic_long_read(&net->n_fetch_bytes));
        seq_printf(m, "file-wr : n=%u nb=%lu\n",
                   atomic_read(&net->n_stores),
                   atomic_long_read(&net->n_store_bytes));
        return 0;
}

/*
 * initialise /proc/fs/afs/<cell>/
 */
int afs_proc_cell_setup(struct afs_cell *cell)
{
        struct proc_dir_entry *dir;
        struct afs_net *net = cell->net;

        _enter("%p{%s},%p", cell, cell->name, net->proc_afs);

        dir = proc_net_mkdir(net->net, cell->name, net->proc_afs);
        if (!dir)
                goto error_dir;

        if (!proc_create_net_data("vlservers", 0444, dir,
                                  &afs_proc_cell_vlservers_ops,
                                  sizeof(struct afs_vl_seq_net_private),
                                  cell) ||
            !proc_create_net_data("volumes", 0444, dir,
                                  &afs_proc_cell_volumes_ops,
                                  sizeof(struct seq_net_private),
                                  cell))
                goto error_tree;

        _leave(" = 0");
        return 0;

error_tree:
        remove_proc_subtree(cell->name, net->proc_afs);
error_dir:
        _leave(" = -ENOMEM");
        return -ENOMEM;
}

/*
 * remove /proc/fs/afs/<cell>/
 */
void afs_proc_cell_remove(struct afs_cell *cell)
{
        struct afs_net *net = cell->net;

        _enter("");
        remove_proc_subtree(cell->name, net->proc_afs);
        _leave("");
}

/*
 * initialise the /proc/fs/afs/ directory
 */
int afs_proc_init(struct afs_net *net)
{
        struct proc_dir_entry *p;

        _enter("");

        p = proc_net_mkdir(net->net, "afs", net->net->proc_net);
        if (!p)
                goto error_dir;

        if (!proc_create_net_data_write("cells", 0644, p,
                                        &afs_proc_cells_ops,
                                        afs_proc_cells_write,
                                        sizeof(struct seq_net_private),
                                        NULL) ||
            !proc_create_net_single_write("rootcell", 0644, p,
                                          afs_proc_rootcell_show,
                                          afs_proc_rootcell_write,
                                          NULL) ||
            !proc_create_net("servers", 0444, p, &afs_proc_servers_ops,
                             sizeof(struct seq_net_private)) ||
            !proc_create_net_single("stats", 0444, p, afs_proc_stats_show, NULL) ||
            !proc_create_net_data_write("sysname", 0644, p,
                                        &afs_proc_sysname_ops,
                                        afs_proc_sysname_write,
                                        sizeof(struct seq_net_private),
                                        NULL))
                goto error_tree;

        net->proc_afs = p;
        _leave(" = 0");
        return 0;

error_tree:
        proc_remove(p);
error_dir:
        _leave(" = -ENOMEM");
        return -ENOMEM;
}

/*
 * clean up the /proc/fs/afs/ directory
 */
void afs_proc_cleanup(struct afs_net *net)
{
        proc_remove(net->proc_afs);
        net->proc_afs = NULL;
}