nommu.c

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/* nommu.c: mmu-less memory info files
 *
 * Copyright (C) 2004 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/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mman.h>
#include <linux/proc_fs.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/seq_file.h>
#include <linux/hugetlb.h>
#include <linux/vmalloc.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
#include <asm/div64.h>
#include "internal.h"

/*
 * display a single region to a sequenced file
 */
static int nommu_region_show(struct seq_file *m, struct vm_region *region)
{
    unsigned long ino = 0;
    struct file *file;
    dev_t dev = 0;
    int flags, len;

    flags = region->vm_flags;
    file = region->vm_file;

    if (file) {
        struct inode *inode = region->vm_file->f_path.dentry->d_inode;
        dev = inode->i_sb->s_dev;
        ino = inode->i_ino;
    }

    seq_printf(m,
           "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
           region->vm_start,
           region->vm_end,
           flags & VM_READ ? 'r' : '-',
           flags & VM_WRITE ? 'w' : '-',
           flags & VM_EXEC ? 'x' : '-',
           flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
           ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
           MAJOR(dev), MINOR(dev), ino, &len);

    if (file) {
        len = 25 + sizeof(void *) * 6 - len;
        if (len < 1)
            len = 1;
        seq_printf(m, "%*c", len, ' ');
        seq_path(m, &file->f_path, "");
    }

    seq_putc(m, '\n');
    return 0;
}

/*
 * display a list of all the REGIONs the kernel knows about
 * - nommu kernels have a single flat list
 */
static int nommu_region_list_show(struct seq_file *m, void *_p)
{
    struct rb_node *p = _p;

    return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
}

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

    down_read(&nommu_region_sem);

    for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
        if (pos-- == 0)
            return p;
    return NULL;
}

static void nommu_region_list_stop(struct seq_file *m, void *v)
{
    up_read(&nommu_region_sem);
}

static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
{
    (*pos)++;
    return rb_next((struct rb_node *) v);
}

static const struct seq_operations proc_nommu_region_list_seqop = {
    .start  = nommu_region_list_start,
    .next   = nommu_region_list_next,
    .stop   = nommu_region_list_stop,
    .show   = nommu_region_list_show
};

static int proc_nommu_region_list_open(struct inode *inode, struct file *file)
{
    return seq_open(file, &proc_nommu_region_list_seqop);
}

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

static int __init proc_nommu_init(void)
{
    proc_create("maps", S_IRUGO, NULL, &proc_nommu_region_list_operations);
    return 0;
}

module_init(proc_nommu_init);