2006-01-08 02:01:43 -07:00
|
|
|
#include <linux/slab.h>
|
|
|
|
#include <linux/string.h>
|
|
|
|
#include <linux/module.h>
|
2006-03-24 04:18:42 -07:00
|
|
|
#include <linux/err.h>
|
|
|
|
#include <asm/uaccess.h>
|
2006-01-08 02:01:43 -07:00
|
|
|
|
|
|
|
/**
|
|
|
|
* 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;
|
2006-10-04 02:15:25 -07:00
|
|
|
buf = kmalloc_track_caller(len, gfp);
|
2006-01-08 02:01:43 -07:00
|
|
|
if (buf)
|
|
|
|
memcpy(buf, s, len);
|
|
|
|
return buf;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kstrdup);
|
2006-03-24 04:18:42 -07:00
|
|
|
|
[PATCH] kmemdup: introduce
One of idiomatic ways to duplicate a region of memory is
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return -ENOMEM;
memcpy(dst, src, len);
which is neat code except a programmer needs to write size twice. Which
sometimes leads to mistakes. If len passed to kmalloc is smaller that len
passed to memcpy, it's straight overwrite-beyond-end. If len passed to
memcpy is smaller than len passed to kmalloc, it's either a) legit
behaviour ;-), or b) cloned buffer will contain garbage in second half.
Slight trolling of commit lists shows several duplications bugs
done exactly because of diverged lenghts:
Linux:
[CRYPTO]: Fix memcpy/memset args.
[PATCH] memcpy/memset fixes
OpenBSD:
kerberosV/src/lib/asn1: der_copy.c:1.4
If programmer is given only one place to play with lengths, I believe, such
mistakes could be avoided.
With kmemdup, the snippet above will be rewritten as:
dst = kmemdup(src, len, GFP_KERNEL);
if (!dst)
return -ENOMEM;
This also leads to smaller code (kzalloc effect). Quick grep shows
200+ places where kmemdup() can be used.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-30 23:27:20 -07:00
|
|
|
/**
|
|
|
|
* 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;
|
|
|
|
|
2006-10-04 02:15:25 -07:00
|
|
|
p = kmalloc_track_caller(len, gfp);
|
[PATCH] kmemdup: introduce
One of idiomatic ways to duplicate a region of memory is
dst = kmalloc(len, GFP_KERNEL);
if (!dst)
return -ENOMEM;
memcpy(dst, src, len);
which is neat code except a programmer needs to write size twice. Which
sometimes leads to mistakes. If len passed to kmalloc is smaller that len
passed to memcpy, it's straight overwrite-beyond-end. If len passed to
memcpy is smaller than len passed to kmalloc, it's either a) legit
behaviour ;-), or b) cloned buffer will contain garbage in second half.
Slight trolling of commit lists shows several duplications bugs
done exactly because of diverged lenghts:
Linux:
[CRYPTO]: Fix memcpy/memset args.
[PATCH] memcpy/memset fixes
OpenBSD:
kerberosV/src/lib/asn1: der_copy.c:1.4
If programmer is given only one place to play with lengths, I believe, such
mistakes could be avoided.
With kmemdup, the snippet above will be rewritten as:
dst = kmemdup(src, len, GFP_KERNEL);
if (!dst)
return -ENOMEM;
This also leads to smaller code (kzalloc effect). Quick grep shows
200+ places where kmemdup() can be used.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-30 23:27:20 -07:00
|
|
|
if (p)
|
|
|
|
memcpy(p, src, len);
|
|
|
|
return p;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kmemdup);
|
|
|
|
|
2007-07-17 04:03:21 -07:00
|
|
|
/**
|
|
|
|
* 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;
|
|
|
|
|
|
|
|
if (unlikely(!new_size)) {
|
|
|
|
kfree(p);
|
2007-07-17 04:03:22 -07:00
|
|
|
return ZERO_SIZE_PTR;
|
2007-07-17 04:03:21 -07:00
|
|
|
}
|
|
|
|
|
|
|
|
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);
|
|
|
|
|
2006-03-24 04:18:42 -07:00
|
|
|
/*
|
|
|
|
* 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);
|