LXR linux/arch/x86/xen/debugfs.c

   1#include <linux/init.h>
   2#include <linux/debugfs.h>
   3#include <linux/slab.h>
   4#include <linux/module.h>
   5
   6#include "debugfs.h"
   7
   8static struct dentry *d_xen_debug;
   9
  10struct dentry * __init xen_init_debugfs(void)
  11{
  12        if (!d_xen_debug) {
  13                d_xen_debug = debugfs_create_dir("xen", NULL);
  14
  15                if (!d_xen_debug)
  16                        pr_warning("Could not create 'xen' debugfs directory\n");
  17        }
  18
  19        return d_xen_debug;
  20}
  21
  22struct array_data
  23{
  24        void *array;
  25        unsigned elements;
  26};
  27
  28static int u32_array_open(struct inode *inode, struct file *file)
  29{
  30        file->private_data = NULL;
  31        return nonseekable_open(inode, file);
  32}
  33
  34static size_t format_array(char *buf, size_t bufsize, const char *fmt,
  35                           u32 *array, unsigned array_size)
  36{
  37        size_t ret = 0;
  38        unsigned i;
  39
  40        for(i = 0; i < array_size; i++) {
  41                size_t len;
  42
  43                len = snprintf(buf, bufsize, fmt, array[i]);
  44                len++;  /* ' ' or '\n' */
  45                ret += len;
  46
  47                if (buf) {
  48                        buf += len;
  49                        bufsize -= len;
  50                        buf[-1] = (i == array_size-1) ? '\n' : ' ';
  51                }
  52        }
  53
  54        ret++;          /* \0 */
  55        if (buf)
  56                *buf = '\0';
  57
  58        return ret;
  59}
  60
  61static char *format_array_alloc(const char *fmt, u32 *array, unsigned array_size)
  62{
  63        size_t len = format_array(NULL, 0, fmt, array, array_size);
  64        char *ret;
  65
  66        ret = kmalloc(len, GFP_KERNEL);
  67        if (ret == NULL)
  68                return NULL;
  69
  70        format_array(ret, len, fmt, array, array_size);
  71        return ret;
  72}
  73
  74static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
  75                              loff_t *ppos)
  76{
  77        struct inode *inode = file->f_path.dentry->d_inode;
  78        struct array_data *data = inode->i_private;
  79        size_t size;
  80
  81        if (*ppos == 0) {
  82                if (file->private_data) {
  83                        kfree(file->private_data);
  84                        file->private_data = NULL;
  85                }
  86
  87                file->private_data = format_array_alloc("%u", data->array, data->elements);
  88        }
  89
  90        size = 0;
  91        if (file->private_data)
  92                size = strlen(file->private_data);
  93
  94        return simple_read_from_buffer(buf, len, ppos, file->private_data, size);
  95}
  96
  97static int xen_array_release(struct inode *inode, struct file *file)
  98{
  99        kfree(file->private_data);
 100
 101        return 0;
 102}
 103
 104static const struct file_operations u32_array_fops = {
 105        .owner  = THIS_MODULE,
 106        .open   = u32_array_open,
 107        .release= xen_array_release,
 108        .read   = u32_array_read,
 109        .llseek = no_llseek,
 110};
 111
 112struct dentry *xen_debugfs_create_u32_array(const char *name, mode_t mode,
 113                                            struct dentry *parent,
 114                                            u32 *array, unsigned elements)
 115{
 116        struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
 117
 118        if (data == NULL)
 119                return NULL;
 120
 121        data->array = array;
 122        data->elements = elements;
 123
 124        return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
 125}
 126