/* /proc interface for AFS
 *
 * Copyright (C) 2002 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/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"

static struct proc_dir_entry *proc_afs;


static int afs_proc_cells_open(struct inode *inode, struct file *file);
static void *afs_proc_cells_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos);
static void afs_proc_cells_stop(struct seq_file *p, void *v);
static int afs_proc_cells_show(struct seq_file *m, void *v);
static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
                                    size_t size, loff_t *_pos);

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,
};

static const struct file_operations afs_proc_cells_fops = {
        .open           = afs_proc_cells_open,
        .read           = seq_read,
        .write          = afs_proc_cells_write,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
                                      size_t size, loff_t *_pos);
static ssize_t afs_proc_rootcell_write(struct file *file,
                                       const char __user *buf,
                                       size_t size, loff_t *_pos);

static const struct file_operations afs_proc_rootcell_fops = {
        .read           = afs_proc_rootcell_read,
        .write          = afs_proc_rootcell_write,
        .llseek         = no_llseek,
};

static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file);
static void *afs_proc_cell_volumes_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
                                        loff_t *pos);
static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v);
static int afs_proc_cell_volumes_show(struct seq_file *m, void *v);

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 struct file_operations afs_proc_cell_volumes_fops = {
        .open           = afs_proc_cell_volumes_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = seq_release,
};

static int afs_proc_cell_vlservers_open(struct inode *inode,
                                        struct file *file);
static void *afs_proc_cell_vlservers_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
                                          loff_t *pos);
static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v);
static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v);

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,
};

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

static int afs_proc_cell_servers_open(struct inode *inode, struct file *file);
static void *afs_proc_cell_servers_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
                                        loff_t *pos);
static void afs_proc_cell_servers_stop(struct seq_file *p, void *v);
static int afs_proc_cell_servers_show(struct seq_file *m, void *v);

static const struct seq_operations afs_proc_cell_servers_ops = {
        .start  = afs_proc_cell_servers_start,
        .next   = afs_proc_cell_servers_next,
        .stop   = afs_proc_cell_servers_stop,
        .show   = afs_proc_cell_servers_show,
};

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

/*
 * initialise the /proc/fs/afs/ directory
 */
int afs_proc_init(void)
{
        _enter("");

        proc_afs = proc_mkdir("fs/afs", NULL);
        if (!proc_afs)
                goto error_dir;

        if (!proc_create("cells", 0644, proc_afs, &afs_proc_cells_fops) ||
            !proc_create("rootcell", 0644, proc_afs, &afs_proc_rootcell_fops))
                goto error_tree;

        _leave(" = 0");
        return 0;

error_tree:
        remove_proc_subtree("fs/afs", NULL);
error_dir:
        _leave(" = -ENOMEM");
        return -ENOMEM;
}

/*
 * clean up the /proc/fs/afs/ directory
 */
void afs_proc_cleanup(void)
{
        remove_proc_subtree("fs/afs", NULL);
}

/*
 * open "/proc/fs/afs/cells" which provides a summary of extant cells
 */
static int afs_proc_cells_open(struct inode *inode, struct file *file)
{
        struct seq_file *m;
        int ret;

        ret = seq_open(file, &afs_proc_cells_ops);
        if (ret < 0)
                return ret;

        m = file->private_data;
        m->private = PDE_DATA(inode);

        return 0;
}

/*
 * set up the iterator to start reading from the cells list and return the
 * first item
 */
static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
{
        /* lock the list against modification */
        down_read(&afs_proc_cells_sem);
        return seq_list_start_head(&afs_proc_cells, *_pos);
}

/*
 * move to next cell in cells list
 */
static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos)
{
        return seq_list_next(v, &afs_proc_cells, pos);
}

/*
 * clean up after reading from the cells list
 */
static void afs_proc_cells_stop(struct seq_file *p, void *v)
{
        up_read(&afs_proc_cells_sem);
}

/*
 * display a header line followed by a load of cell lines
 */
static int afs_proc_cells_show(struct seq_file *m, void *v)
{
        struct afs_cell *cell = list_entry(v, struct afs_cell, proc_link);

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

        /* display one cell per line on subsequent lines */
        seq_printf(m, "%3d %s\n",
                   atomic_read(&cell->usage), cell->name);
        return 0;
}

/*
 * handle writes to /proc/fs/afs/cells
 * - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
 */
static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
                                    size_t size, loff_t *_pos)
{
        char *kbuf, *name, *args;
        int ret;

        /* start by dragging the command into memory */
        if (size <= 1 || size >= PAGE_SIZE)
                return -EINVAL;

        kbuf = memdup_user_nul(buf, size);
        if (IS_ERR(kbuf))
                return PTR_ERR(kbuf);

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

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

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

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

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

                cell = afs_cell_create(name, strlen(name), args, false);
                if (IS_ERR(cell)) {
                        ret = PTR_ERR(cell);
                        goto done;
                }

                afs_put_cell(cell);
                printk("kAFS: Added new cell '%s'\n", name);
        } else {
                goto inval;
        }

        ret = size;

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

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

static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
                                      size_t size, loff_t *_pos)
{
        return 0;
}

/*
 * handle writes to /proc/fs/afs/rootcell
 * - to initialize rootcell: echo "cell.name:192.168.231.14"
 */
static ssize_t afs_proc_rootcell_write(struct file *file,
                                       const char __user *buf,
                                       size_t size, loff_t *_pos)
{
        char *kbuf, *s;
        int ret;

        /* start by dragging the command into memory */
        if (size <= 1 || size >= PAGE_SIZE)
                return -EINVAL;

        kbuf = memdup_user_nul(buf, size);
        if (IS_ERR(kbuf))
                return PTR_ERR(kbuf);

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

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

        ret = afs_cell_init(kbuf);
        if (ret >= 0)
                ret = size;     /* consume everything, always */

        kfree(kbuf);
        _leave(" = %d", ret);
        return ret;
}

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

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

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

        if (!proc_create_data("servers", 0, dir,
                             &afs_proc_cell_servers_fops, cell) ||
            !proc_create_data("vlservers", 0, dir,
                             &afs_proc_cell_vlservers_fops, cell) ||
            !proc_create_data("volumes", 0, dir,
                             &afs_proc_cell_volumes_fops, cell))
                goto error_tree;

        _leave(" = 0");
        return 0;

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

/*
 * remove /proc/fs/afs/<cell>/
 */
void afs_proc_cell_remove(struct afs_cell *cell)
{
        _enter("");

        remove_proc_subtree(cell->name, proc_afs);

        _leave("");
}

/*
 * open "/proc/fs/afs/<cell>/volumes" which provides a summary of extant cells
 */
static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file)
{
        struct afs_cell *cell;
        struct seq_file *m;
        int ret;

        cell = PDE_DATA(inode);
        if (!cell)
                return -ENOENT;

        ret = seq_open(file, &afs_proc_cell_volumes_ops);
        if (ret < 0)
                return ret;

        m = file->private_data;
        m->private = cell;

        return 0;
}

/*
 * set up the iterator to start reading from the cells list and return the
 * first item
 */
static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
{
        struct afs_cell *cell = m->private;

        _enter("cell=%p pos=%Ld", cell, *_pos);

        /* lock the list against modification */
        down_read(&cell->vl_sem);
        return seq_list_start_head(&cell->vl_list, *_pos);
}

/*
 * move to next cell in cells list
 */
static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
                                        loff_t *_pos)
{
        struct afs_cell *cell = p->private;

        _enter("cell=%p pos=%Ld", cell, *_pos);
        return seq_list_next(v, &cell->vl_list, _pos);
}

/*
 * clean up after reading from the cells list
 */
static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v)
{
        struct afs_cell *cell = p->private;

        up_read(&cell->vl_sem);
}

static const char afs_vlocation_states[][4] = {
        [AFS_VL_NEW]                    = "New",
        [AFS_VL_CREATING]               = "Crt",
        [AFS_VL_VALID]                  = "Val",
        [AFS_VL_NO_VOLUME]              = "NoV",
        [AFS_VL_UPDATING]               = "Upd",
        [AFS_VL_VOLUME_DELETED]         = "Del",
        [AFS_VL_UNCERTAIN]              = "Unc",
};

/*
 * display a header line followed by a load of volume lines
 */
static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
{
        struct afs_cell *cell = m->private;
        struct afs_vlocation *vlocation =
                list_entry(v, struct afs_vlocation, link);

        /* display header on line 1 */
        if (v == &cell->vl_list) {
                seq_puts(m, "USE STT VLID[0]  VLID[1]  VLID[2]  NAME\n");
                return 0;
        }

        /* display one cell per line on subsequent lines */
        seq_printf(m, "%3d %s %08x %08x %08x %s\n",
                   atomic_read(&vlocation->usage),
                   afs_vlocation_states[vlocation->state],
                   vlocation->vldb.vid[0],
                   vlocation->vldb.vid[1],
                   vlocation->vldb.vid[2],
                   vlocation->vldb.name);

        return 0;
}

/*
 * open "/proc/fs/afs/<cell>/vlservers" which provides a list of volume
 * location server
 */
static int afs_proc_cell_vlservers_open(struct inode *inode, struct file *file)
{
        struct afs_cell *cell;
        struct seq_file *m;
        int ret;

        cell = PDE_DATA(inode);
        if (!cell)
                return -ENOENT;

        ret = seq_open(file, &afs_proc_cell_vlservers_ops);
        if (ret<0)
                return ret;

        m = file->private_data;
        m->private = cell;

        return 0;
}

/*
 * set up the iterator to start reading from the cells list and return the
 * first item
 */
static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
{
        struct afs_cell *cell = m->private;
        loff_t pos = *_pos;

        _enter("cell=%p pos=%Ld", cell, *_pos);

        /* lock the list against modification */
        down_read(&cell->vl_sem);

        /* allow for the header line */
        if (!pos)
                return (void *) 1;
        pos--;

        if (pos >= cell->vl_naddrs)
                return NULL;

        return &cell->vl_addrs[pos];
}

/*
 * move to next cell in cells list
 */
static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
                                          loff_t *_pos)
{
        struct afs_cell *cell = p->private;
        loff_t pos;

        _enter("cell=%p{nad=%u} pos=%Ld", cell, cell->vl_naddrs, *_pos);

        pos = *_pos;
        (*_pos)++;
        if (pos >= cell->vl_naddrs)
                return NULL;

        return &cell->vl_addrs[pos];
}

/*
 * clean up after reading from the cells list
 */
static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v)
{
        struct afs_cell *cell = p->private;

        up_read(&cell->vl_sem);
}

/*
 * display a header line followed by a load of volume lines
 */
static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
{
        struct in_addr *addr = v;

        /* display header on line 1 */
        if (v == (struct in_addr *) 1) {
                seq_puts(m, "ADDRESS\n");
                return 0;
        }

        /* display one cell per line on subsequent lines */
        seq_printf(m, "%pI4\n", &addr->s_addr);
        return 0;
}

/*
 * open "/proc/fs/afs/<cell>/servers" which provides a summary of active
 * servers
 */
static int afs_proc_cell_servers_open(struct inode *inode, struct file *file)
{
        struct afs_cell *cell;
        struct seq_file *m;
        int ret;

        cell = PDE_DATA(inode);
        if (!cell)
                return -ENOENT;

        ret = seq_open(file, &afs_proc_cell_servers_ops);
        if (ret < 0)
                return ret;

        m = file->private_data;
        m->private = cell;
        return 0;
}

/*
 * set up the iterator to start reading from the cells list and return the
 * first item
 */
static void *afs_proc_cell_servers_start(struct seq_file *m, loff_t *_pos)
        __acquires(m->private->servers_lock)
{
        struct afs_cell *cell = m->private;

        _enter("cell=%p pos=%Ld", cell, *_pos);

        /* lock the list against modification */
        read_lock(&cell->servers_lock);
        return seq_list_start_head(&cell->servers, *_pos);
}

/*
 * move to next cell in cells list
 */
static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
                                        loff_t *_pos)
{
        struct afs_cell *cell = p->private;

        _enter("cell=%p pos=%Ld", cell, *_pos);
        return seq_list_next(v, &cell->servers, _pos);
}

/*
 * clean up after reading from the cells list
 */
static void afs_proc_cell_servers_stop(struct seq_file *p, void *v)
        __releases(p->private->servers_lock)
{
        struct afs_cell *cell = p->private;

        read_unlock(&cell->servers_lock);
}

/*
 * display a header line followed by a load of volume lines
 */
static int afs_proc_cell_servers_show(struct seq_file *m, void *v)
{
        struct afs_cell *cell = m->private;
        struct afs_server *server = list_entry(v, struct afs_server, link);
        char ipaddr[20];

        /* display header on line 1 */
        if (v == &cell->servers) {
                seq_puts(m, "USE ADDR            STATE\n");
                return 0;
        }

        /* display one cell per line on subsequent lines */
        sprintf(ipaddr, "%pI4", &server->addr);
        seq_printf(m, "%3d %-15.15s %5d\n",
                   atomic_read(&server->usage), ipaddr, server->fs_state);

        return 0;
}