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30992c97 MM |
1 | #include <linux/slab.h> |
2 | #include <linux/string.h> | |
3 | #include <linux/module.h> | |
96840aa0 DA |
4 | #include <linux/err.h> |
5 | #include <asm/uaccess.h> | |
30992c97 MM |
6 | |
7 | /** | |
30992c97 MM |
8 | * kstrdup - allocate space for and copy an existing string |
9 | * | |
10 | * @s: the string to duplicate | |
11 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
12 | */ | |
13 | char *kstrdup(const char *s, gfp_t gfp) | |
14 | { | |
15 | size_t len; | |
16 | char *buf; | |
17 | ||
18 | if (!s) | |
19 | return NULL; | |
20 | ||
21 | len = strlen(s) + 1; | |
1d2c8eea | 22 | buf = kmalloc_track_caller(len, gfp); |
30992c97 MM |
23 | if (buf) |
24 | memcpy(buf, s, len); | |
25 | return buf; | |
26 | } | |
27 | EXPORT_SYMBOL(kstrdup); | |
96840aa0 | 28 | |
1a2f67b4 AD |
29 | /** |
30 | * kmemdup - duplicate region of memory | |
31 | * | |
32 | * @src: memory region to duplicate | |
33 | * @len: memory region length | |
34 | * @gfp: GFP mask to use | |
35 | */ | |
36 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
37 | { | |
38 | void *p; | |
39 | ||
1d2c8eea | 40 | p = kmalloc_track_caller(len, gfp); |
1a2f67b4 AD |
41 | if (p) |
42 | memcpy(p, src, len); | |
43 | return p; | |
44 | } | |
45 | EXPORT_SYMBOL(kmemdup); | |
46 | ||
ef2ad80c CL |
47 | /** |
48 | * krealloc - reallocate memory. The contents will remain unchanged. | |
49 | * @p: object to reallocate memory for. | |
50 | * @new_size: how many bytes of memory are required. | |
51 | * @flags: the type of memory to allocate. | |
52 | * | |
53 | * The contents of the object pointed to are preserved up to the | |
54 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
55 | * behaves exactly like kmalloc(). If @size is 0 and @p is not a | |
56 | * %NULL pointer, the object pointed to is freed. | |
57 | */ | |
58 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
59 | { | |
60 | void *ret; | |
61 | size_t ks; | |
62 | ||
63 | if (unlikely(!new_size)) { | |
64 | kfree(p); | |
6cb8f913 | 65 | return ZERO_SIZE_PTR; |
ef2ad80c CL |
66 | } |
67 | ||
68 | ks = ksize(p); | |
69 | if (ks >= new_size) | |
70 | return (void *)p; | |
71 | ||
72 | ret = kmalloc_track_caller(new_size, flags); | |
73 | if (ret) { | |
74 | memcpy(ret, p, min(new_size, ks)); | |
75 | kfree(p); | |
76 | } | |
77 | return ret; | |
78 | } | |
79 | EXPORT_SYMBOL(krealloc); | |
80 | ||
96840aa0 DA |
81 | /* |
82 | * strndup_user - duplicate an existing string from user space | |
83 | * | |
84 | * @s: The string to duplicate | |
85 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
86 | */ | |
87 | char *strndup_user(const char __user *s, long n) | |
88 | { | |
89 | char *p; | |
90 | long length; | |
91 | ||
92 | length = strnlen_user(s, n); | |
93 | ||
94 | if (!length) | |
95 | return ERR_PTR(-EFAULT); | |
96 | ||
97 | if (length > n) | |
98 | return ERR_PTR(-EINVAL); | |
99 | ||
100 | p = kmalloc(length, GFP_KERNEL); | |
101 | ||
102 | if (!p) | |
103 | return ERR_PTR(-ENOMEM); | |
104 | ||
105 | if (copy_from_user(p, s, length)) { | |
106 | kfree(p); | |
107 | return ERR_PTR(-EFAULT); | |
108 | } | |
109 | ||
110 | p[length - 1] = '\0'; | |
111 | ||
112 | return p; | |
113 | } | |
114 | EXPORT_SYMBOL(strndup_user); |