proc.c

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/* /proc interface for AFS
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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 <asm/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,
    .owner      = THIS_MODULE,
};

static int afs_proc_rootcell_open(struct inode *inode, struct file *file);
static int afs_proc_rootcell_release(struct inode *inode, struct file *file);
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 = {
    .open       = afs_proc_rootcell_open,
    .read       = afs_proc_rootcell_read,
    .write      = afs_proc_rootcell_write,
    .llseek     = no_llseek,
    .release    = afs_proc_rootcell_release,
    .owner      = THIS_MODULE,
};

static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file);
static int afs_proc_cell_volumes_release(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    = afs_proc_cell_volumes_release,
    .owner      = THIS_MODULE,
};

static int afs_proc_cell_vlservers_open(struct inode *inode,
                    struct file *file);
static int afs_proc_cell_vlservers_release(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    = afs_proc_cell_vlservers_release,
    .owner      = THIS_MODULE,
};

static int afs_proc_cell_servers_open(struct inode *inode, struct file *file);
static int afs_proc_cell_servers_release(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    = afs_proc_cell_servers_release,
    .owner      = THIS_MODULE,
};

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

    _enter("");

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

    p = proc_create("cells", 0, proc_afs, &afs_proc_cells_fops);
    if (!p)
        goto error_cells;

    p = proc_create("rootcell", 0, proc_afs, &afs_proc_rootcell_fops);
    if (!p)
        goto error_rootcell;

    _leave(" = 0");
    return 0;

error_rootcell:
    remove_proc_entry("cells", proc_afs);
error_cells:
    remove_proc_entry("fs/afs", NULL);
error_dir:
    _leave(" = -ENOMEM");
    return -ENOMEM;
}

/*
 * clean up the /proc/fs/afs/ directory
 */
void afs_proc_cleanup(void)
{
    remove_proc_entry("rootcell", proc_afs);
    remove_proc_entry("cells", proc_afs);
    remove_proc_entry("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(inode)->data;

    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 = kmalloc(size + 1, GFP_KERNEL);
    if (!kbuf)
        return -ENOMEM;

    ret = -EFAULT;
    if (copy_from_user(kbuf, buf, size) != 0)
        goto done;
    kbuf[size] = 0;

    /* 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;
}

/*
 * Stubs for /proc/fs/afs/rootcell
 */
static int afs_proc_rootcell_open(struct inode *inode, struct file *file)
{
    return 0;
}

static int afs_proc_rootcell_release(struct inode *inode, struct file *file)
{
    return 0;
}

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;

    ret = -ENOMEM;
    kbuf = kmalloc(size + 1, GFP_KERNEL);
    if (!kbuf)
        goto nomem;

    ret = -EFAULT;
    if (copy_from_user(kbuf, buf, size) != 0)
        goto infault;
    kbuf[size] = 0;

    /* 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 */

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

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

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

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

    p = proc_create_data("servers", 0, cell->proc_dir,
                 &afs_proc_cell_servers_fops, cell);
    if (!p)
        goto error_servers;

    p = proc_create_data("vlservers", 0, cell->proc_dir,
                 &afs_proc_cell_vlservers_fops, cell);
    if (!p)
        goto error_vlservers;

    p = proc_create_data("volumes", 0, cell->proc_dir,
                 &afs_proc_cell_volumes_fops, cell);
    if (!p)
        goto error_volumes;

    _leave(" = 0");
    return 0;

error_volumes:
    remove_proc_entry("vlservers", cell->proc_dir);
error_vlservers:
    remove_proc_entry("servers", cell->proc_dir);
error_servers:
    remove_proc_entry(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_entry("volumes", cell->proc_dir);
    remove_proc_entry("vlservers", cell->proc_dir);
    remove_proc_entry("servers", cell->proc_dir);
    remove_proc_entry(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(inode)->data;
    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;
}

/*
 * close the file and release the ref to the cell
 */
static int afs_proc_cell_volumes_release(struct inode *inode, struct file *file)
{
    return seq_release(inode, file);
}

/*
 * 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(inode)->data;
    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;
}

/*
 * close the file and release the ref to the cell
 */
static int afs_proc_cell_vlservers_release(struct inode *inode,
                       struct file *file)
{
    return seq_release(inode, file);
}

/*
 * 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(inode)->data;
    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;
}

/*
 * close the file and release the ref to the cell
 */
static int afs_proc_cell_servers_release(struct inode *inode,
                     struct file *file)
{
    return seq_release(inode, file);
}

/*
 * 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;
}