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

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