/* proc.c: proc files for key database enumeration
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/errno.h>
#include "internal.h"

#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
static int proc_keys_open(struct inode *inode, struct file *file);
static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
static void proc_keys_stop(struct seq_file *p, void *v);
static int proc_keys_show(struct seq_file *m, void *v);

static const struct seq_operations proc_keys_ops = {
        .start  = proc_keys_start,
        .next   = proc_keys_next,
        .stop   = proc_keys_stop,
        .show   = proc_keys_show,
};

static const struct file_operations proc_keys_fops = {
        .open           = proc_keys_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};
#endif

static int proc_key_users_open(struct inode *inode, struct file *file);
static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
static void proc_key_users_stop(struct seq_file *p, void *v);
static int proc_key_users_show(struct seq_file *m, void *v);

static const struct seq_operations proc_key_users_ops = {
        .start  = proc_key_users_start,
        .next   = proc_key_users_next,
        .stop   = proc_key_users_stop,
        .show   = proc_key_users_show,
};

static const struct file_operations proc_key_users_fops = {
        .open           = proc_key_users_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

/*****************************************************************************/
/*
 * declare the /proc files
 */
static int __init key_proc_init(void)
{
        struct proc_dir_entry *p;

#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
        p = proc_create("keys", 0, NULL, &proc_keys_fops);
        if (!p)
                panic("Cannot create /proc/keys\n");
#endif

        p = proc_create("key-users", 0, NULL, &proc_key_users_fops);
        if (!p)
                panic("Cannot create /proc/key-users\n");

        return 0;

} /* end key_proc_init() */

__initcall(key_proc_init);

/*****************************************************************************/
/*
 * implement "/proc/keys" to provides a list of the keys on the system
 */
#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS

static struct rb_node *__key_serial_next(struct rb_node *n)
{
        while (n) {
                struct key *key = rb_entry(n, struct key, serial_node);
                if (key->user->user_ns == current_user_ns())
                        break;
                n = rb_next(n);
        }
        return n;
}

static struct rb_node *key_serial_next(struct rb_node *n)
{
        return __key_serial_next(rb_next(n));
}

static struct rb_node *key_serial_first(struct rb_root *r)
{
        struct rb_node *n = rb_first(r);
        return __key_serial_next(n);
}

static int proc_keys_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &proc_keys_ops);

}

static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
{
        struct rb_node *_p;
        loff_t pos = *_pos;

        spin_lock(&key_serial_lock);

        _p = key_serial_first(&key_serial_tree);
        while (pos > 0 && _p) {
                pos--;
                _p = key_serial_next(_p);
        }

        return _p;

}

static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
{
        (*_pos)++;
        return key_serial_next((struct rb_node *) v);

}

static void proc_keys_stop(struct seq_file *p, void *v)
{
        spin_unlock(&key_serial_lock);
}

static int proc_keys_show(struct seq_file *m, void *v)
{
        struct rb_node *_p = v;
        struct key *key = rb_entry(_p, struct key, serial_node);
        struct timespec now;
        unsigned long timo;
        char xbuf[12];
        int rc;

        /* check whether the current task is allowed to view the key (assuming
         * non-possession)
         * - the caller holds a spinlock, and thus the RCU read lock, making our
         *   access to __current_cred() safe
         */
        rc = key_task_permission(make_key_ref(key, 0), current_cred(),
                                 KEY_VIEW);
        if (rc < 0)
                return 0;

        now = current_kernel_time();

        rcu_read_lock();

        /* come up with a suitable timeout value */
        if (key->expiry == 0) {
                memcpy(xbuf, "perm", 5);
        }
        else if (now.tv_sec >= key->expiry) {
                memcpy(xbuf, "expd", 5);
        }
        else {
                timo = key->expiry - now.tv_sec;

                if (timo < 60)
                        sprintf(xbuf, "%lus", timo);
                else if (timo < 60*60)
                        sprintf(xbuf, "%lum", timo / 60);
                else if (timo < 60*60*24)
                        sprintf(xbuf, "%luh", timo / (60*60));
                else if (timo < 60*60*24*7)
                        sprintf(xbuf, "%lud", timo / (60*60*24));
                else
                        sprintf(xbuf, "%luw", timo / (60*60*24*7));
        }

#define showflag(KEY, LETTER, FLAG) \
        (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-')

        seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
                   key->serial,
                   showflag(key, 'I', KEY_FLAG_INSTANTIATED),
                   showflag(key, 'R', KEY_FLAG_REVOKED),
                   showflag(key, 'D', KEY_FLAG_DEAD),
                   showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
                   showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
                   showflag(key, 'N', KEY_FLAG_NEGATIVE),
                   atomic_read(&key->usage),
                   xbuf,
                   key->perm,
                   key->uid,
                   key->gid,
                   key->type->name);

#undef showflag

        if (key->type->describe)
                key->type->describe(key, m);
        seq_putc(m, '\n');

        rcu_read_unlock();

        return 0;

}

#endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */

static struct rb_node *__key_user_next(struct rb_node *n)
{
        while (n) {
                struct key_user *user = rb_entry(n, struct key_user, node);
                if (user->user_ns == current_user_ns())
                        break;
                n = rb_next(n);
        }
        return n;
}

static struct rb_node *key_user_next(struct rb_node *n)
{
        return __key_user_next(rb_next(n));
}

static struct rb_node *key_user_first(struct rb_root *r)
{
        struct rb_node *n = rb_first(r);
        return __key_user_next(n);
}
/*****************************************************************************/
/*
 * implement "/proc/key-users" to provides a list of the key users
 */
static int proc_key_users_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &proc_key_users_ops);

}

static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
{
        struct rb_node *_p;
        loff_t pos = *_pos;

        spin_lock(&key_user_lock);

        _p = key_user_first(&key_user_tree);
        while (pos > 0 && _p) {
                pos--;
                _p = key_user_next(_p);
        }

        return _p;

}

static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
{
        (*_pos)++;
        return key_user_next((struct rb_node *) v);

}

static void proc_key_users_stop(struct seq_file *p, void *v)
{
        spin_unlock(&key_user_lock);
}

static int proc_key_users_show(struct seq_file *m, void *v)
{
        struct rb_node *_p = v;
        struct key_user *user = rb_entry(_p, struct key_user, node);
        unsigned maxkeys = (user->uid == 0) ?
                key_quota_root_maxkeys : key_quota_maxkeys;
        unsigned maxbytes = (user->uid == 0) ?
                key_quota_root_maxbytes : key_quota_maxbytes;

        seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
                   user->uid,
                   atomic_read(&user->usage),
                   atomic_read(&user->nkeys),
                   atomic_read(&user->nikeys),
                   user->qnkeys,
                   maxkeys,
                   user->qnbytes,
                   maxbytes);

        return 0;

}