LXR linux/mm/util.c

   1#include <linux/slab.h>
   2#include <linux/string.h>
   3#include <linux/module.h>
   4#include <linux/err.h>
   5#include <asm/uaccess.h>
   6
   7/**
   8 * __kzalloc - allocate memory. The memory is set to zero.
   9 * @size: how many bytes of memory are required.
  10 * @flags: the type of memory to allocate.
  11 */
  12void *__kzalloc(size_t size, gfp_t flags)
  13{
  14        void *ret = kmalloc_track_caller(size, flags);
  15        if (ret)
  16                memset(ret, 0, size);
  17        return ret;
  18}
  19EXPORT_SYMBOL(__kzalloc);
  20
  21/*
  22 * kstrdup - allocate space for and copy an existing string
  23 *
  24 * @s: the string to duplicate
  25 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
  26 */
  27char *kstrdup(const char *s, gfp_t gfp)
  28{
  29        size_t len;
  30        char *buf;
  31
  32        if (!s)
  33                return NULL;
  34
  35        len = strlen(s) + 1;
  36        buf = kmalloc_track_caller(len, gfp);
  37        if (buf)
  38                memcpy(buf, s, len);
  39        return buf;
  40}
  41EXPORT_SYMBOL(kstrdup);
  42
  43/**
  44 * kmemdup - duplicate region of memory
  45 *
  46 * @src: memory region to duplicate
  47 * @len: memory region length
  48 * @gfp: GFP mask to use
  49 */
  50void *kmemdup(const void *src, size_t len, gfp_t gfp)
  51{
  52        void *p;
  53
  54        p = kmalloc_track_caller(len, gfp);
  55        if (p)
  56                memcpy(p, src, len);
  57        return p;
  58}
  59EXPORT_SYMBOL(kmemdup);
  60
  61/*
  62 * strndup_user - duplicate an existing string from user space
  63 *
  64 * @s: The string to duplicate
  65 * @n: Maximum number of bytes to copy, including the trailing NUL.
  66 */
  67char *strndup_user(const char __user *s, long n)
  68{
  69        char *p;
  70        long length;
  71
  72        length = strnlen_user(s, n);
  73
  74        if (!length)
  75                return ERR_PTR(-EFAULT);
  76
  77        if (length > n)
  78                return ERR_PTR(-EINVAL);
  79
  80        p = kmalloc(length, GFP_KERNEL);
  81
  82        if (!p)
  83                return ERR_PTR(-ENOMEM);
  84
  85        if (copy_from_user(p, s, length)) {
  86                kfree(p);
  87                return ERR_PTR(-EFAULT);
  88        }
  89
  90        p[length - 1] = '\0';
  91
  92        return p;
  93}
  94EXPORT_SYMBOL(strndup_user);
  95