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#include <linux/slab.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/err.h>
#include <asm/uaccess.h>
/**
* kzalloc - allocate memory. The memory is set to zero.
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate.
*/
void *kzalloc(size_t size, gfp_t flags)
{
void *ret = kmalloc(size, flags);
if (ret)
memset(ret, 0, size);
return ret;
}
EXPORT_SYMBOL(kzalloc);
/*
* kstrdup - allocate space for and copy an existing string
*
* @s: the string to duplicate
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*/
char *kstrdup(const char *s, gfp_t gfp)
{
size_t len;
char *buf;
if (!s)
return NULL;
len = strlen(s) + 1;
buf = kmalloc(len, gfp);
if (buf)
memcpy(buf, s, len);
return buf;
}
EXPORT_SYMBOL(kstrdup);
/*
* strndup_user - duplicate an existing string from user space
*
* @s: The string to duplicate
* @n: Maximum number of bytes to copy, including the trailing NUL.
*/
char *strndup_user(const char __user *s, long n)
{
char *p;
long length;
length = strnlen_user(s, n);
if (!length)
return ERR_PTR(-EFAULT);
if (length > n)
return ERR_PTR(-EINVAL);
p = kmalloc(length, GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);
if (copy_from_user(p, s, length)) {
kfree(p);
return ERR_PTR(-EFAULT);
}
p[length - 1] = '\0';
return p;
}
EXPORT_SYMBOL(strndup_user);
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