blob: bf340d80686884bf765dc696a73f7fd840842e8f [file] [log] [blame]
Matt Mackall30992c92006-01-08 01:01:43 -08001#include <linux/slab.h>
2#include <linux/string.h>
3#include <linux/module.h>
Davi Arnaut96840aa2006-03-24 03:18:42 -08004#include <linux/err.h>
5#include <asm/uaccess.h>
Matt Mackall30992c92006-01-08 01:01:43 -08006
7/**
Matt Mackall30992c92006-01-08 01:01:43 -08008 * kstrdup - allocate space for and copy an existing string
Matt Mackall30992c92006-01-08 01:01:43 -08009 * @s: the string to duplicate
10 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
11 */
12char *kstrdup(const char *s, gfp_t gfp)
13{
14 size_t len;
15 char *buf;
16
17 if (!s)
18 return NULL;
19
20 len = strlen(s) + 1;
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -070021 buf = kmalloc_track_caller(len, gfp);
Matt Mackall30992c92006-01-08 01:01:43 -080022 if (buf)
23 memcpy(buf, s, len);
24 return buf;
25}
26EXPORT_SYMBOL(kstrdup);
Davi Arnaut96840aa2006-03-24 03:18:42 -080027
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070028/**
Jeremy Fitzhardinge1e66df32007-07-17 18:37:02 -070029 * kstrndup - allocate space for and copy an existing string
30 * @s: the string to duplicate
31 * @max: read at most @max chars from @s
32 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
33 */
34char *kstrndup(const char *s, size_t max, gfp_t gfp)
35{
36 size_t len;
37 char *buf;
38
39 if (!s)
40 return NULL;
41
42 len = strnlen(s, max);
43 buf = kmalloc_track_caller(len+1, gfp);
44 if (buf) {
45 memcpy(buf, s, len);
46 buf[len] = '\0';
47 }
48 return buf;
49}
50EXPORT_SYMBOL(kstrndup);
51
52/**
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070053 * kmemdup - duplicate region of memory
54 *
55 * @src: memory region to duplicate
56 * @len: memory region length
57 * @gfp: GFP mask to use
58 */
59void *kmemdup(const void *src, size_t len, gfp_t gfp)
60{
61 void *p;
62
Christoph Hellwig1d2c8ee2006-10-04 02:15:25 -070063 p = kmalloc_track_caller(len, gfp);
Alexey Dobriyan1a2f67b2006-09-30 23:27:20 -070064 if (p)
65 memcpy(p, src, len);
66 return p;
67}
68EXPORT_SYMBOL(kmemdup);
69
Christoph Lameteref2ad802007-07-17 04:03:21 -070070/**
71 * krealloc - reallocate memory. The contents will remain unchanged.
72 * @p: object to reallocate memory for.
73 * @new_size: how many bytes of memory are required.
74 * @flags: the type of memory to allocate.
75 *
76 * The contents of the object pointed to are preserved up to the
77 * lesser of the new and old sizes. If @p is %NULL, krealloc()
78 * behaves exactly like kmalloc(). If @size is 0 and @p is not a
79 * %NULL pointer, the object pointed to is freed.
80 */
81void *krealloc(const void *p, size_t new_size, gfp_t flags)
82{
83 void *ret;
84 size_t ks;
85
86 if (unlikely(!new_size)) {
87 kfree(p);
Christoph Lameter6cb8f912007-07-17 04:03:22 -070088 return ZERO_SIZE_PTR;
Christoph Lameteref2ad802007-07-17 04:03:21 -070089 }
90
91 ks = ksize(p);
92 if (ks >= new_size)
93 return (void *)p;
94
95 ret = kmalloc_track_caller(new_size, flags);
96 if (ret) {
97 memcpy(ret, p, min(new_size, ks));
98 kfree(p);
99 }
100 return ret;
101}
102EXPORT_SYMBOL(krealloc);
103
Davi Arnaut96840aa2006-03-24 03:18:42 -0800104/*
105 * strndup_user - duplicate an existing string from user space
Davi Arnaut96840aa2006-03-24 03:18:42 -0800106 * @s: The string to duplicate
107 * @n: Maximum number of bytes to copy, including the trailing NUL.
108 */
109char *strndup_user(const char __user *s, long n)
110{
111 char *p;
112 long length;
113
114 length = strnlen_user(s, n);
115
116 if (!length)
117 return ERR_PTR(-EFAULT);
118
119 if (length > n)
120 return ERR_PTR(-EINVAL);
121
122 p = kmalloc(length, GFP_KERNEL);
123
124 if (!p)
125 return ERR_PTR(-ENOMEM);
126
127 if (copy_from_user(p, s, length)) {
128 kfree(p);
129 return ERR_PTR(-EFAULT);
130 }
131
132 p[length - 1] = '\0';
133
134 return p;
135}
136EXPORT_SYMBOL(strndup_user);