mirror of
https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
synced 2025-10-31 06:54:45 +10:00
ef8b4520bd
A NULL pointer means that the object was not allocated. One cannot determine the size of an object that has not been allocated. Currently we return 0 but we really should BUG() on attempts to determine the size of something nonexistent. krealloc() interprets NULL to mean a zero sized object. Handle that separately in krealloc(). Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
139 lines
2.7 KiB
C
139 lines
2.7 KiB
C
#include <linux/slab.h>
|
|
#include <linux/string.h>
|
|
#include <linux/module.h>
|
|
#include <linux/err.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
/**
|
|
* 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_track_caller(len, gfp);
|
|
if (buf)
|
|
memcpy(buf, s, len);
|
|
return buf;
|
|
}
|
|
EXPORT_SYMBOL(kstrdup);
|
|
|
|
/**
|
|
* kstrndup - allocate space for and copy an existing string
|
|
* @s: the string to duplicate
|
|
* @max: read at most @max chars from @s
|
|
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
|
|
*/
|
|
char *kstrndup(const char *s, size_t max, gfp_t gfp)
|
|
{
|
|
size_t len;
|
|
char *buf;
|
|
|
|
if (!s)
|
|
return NULL;
|
|
|
|
len = strnlen(s, max);
|
|
buf = kmalloc_track_caller(len+1, gfp);
|
|
if (buf) {
|
|
memcpy(buf, s, len);
|
|
buf[len] = '\0';
|
|
}
|
|
return buf;
|
|
}
|
|
EXPORT_SYMBOL(kstrndup);
|
|
|
|
/**
|
|
* kmemdup - duplicate region of memory
|
|
*
|
|
* @src: memory region to duplicate
|
|
* @len: memory region length
|
|
* @gfp: GFP mask to use
|
|
*/
|
|
void *kmemdup(const void *src, size_t len, gfp_t gfp)
|
|
{
|
|
void *p;
|
|
|
|
p = kmalloc_track_caller(len, gfp);
|
|
if (p)
|
|
memcpy(p, src, len);
|
|
return p;
|
|
}
|
|
EXPORT_SYMBOL(kmemdup);
|
|
|
|
/**
|
|
* krealloc - reallocate memory. The contents will remain unchanged.
|
|
* @p: object to reallocate memory for.
|
|
* @new_size: how many bytes of memory are required.
|
|
* @flags: the type of memory to allocate.
|
|
*
|
|
* The contents of the object pointed to are preserved up to the
|
|
* lesser of the new and old sizes. If @p is %NULL, krealloc()
|
|
* behaves exactly like kmalloc(). If @size is 0 and @p is not a
|
|
* %NULL pointer, the object pointed to is freed.
|
|
*/
|
|
void *krealloc(const void *p, size_t new_size, gfp_t flags)
|
|
{
|
|
void *ret;
|
|
size_t ks = 0;
|
|
|
|
if (unlikely(!new_size)) {
|
|
kfree(p);
|
|
return ZERO_SIZE_PTR;
|
|
}
|
|
|
|
if (p)
|
|
ks = ksize(p);
|
|
|
|
if (ks >= new_size)
|
|
return (void *)p;
|
|
|
|
ret = kmalloc_track_caller(new_size, flags);
|
|
if (ret) {
|
|
memcpy(ret, p, min(new_size, ks));
|
|
kfree(p);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(krealloc);
|
|
|
|
/*
|
|
* 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);
|