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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 | 8 | * kstrdup - allocate space for and copy an existing string |
30992c97 MM |
9 | * @s: the string to duplicate |
10 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
11 | */ | |
12 | char *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; | |
1d2c8eea | 21 | buf = kmalloc_track_caller(len, gfp); |
30992c97 MM |
22 | if (buf) |
23 | memcpy(buf, s, len); | |
24 | return buf; | |
25 | } | |
26 | EXPORT_SYMBOL(kstrdup); | |
96840aa0 | 27 | |
1e66df3e JF |
28 | /** |
29 | * 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 | */ | |
34 | char *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 | } | |
50 | EXPORT_SYMBOL(kstrndup); | |
51 | ||
1a2f67b4 AD |
52 | /** |
53 | * kmemdup - duplicate region of memory | |
54 | * | |
55 | * @src: memory region to duplicate | |
56 | * @len: memory region length | |
57 | * @gfp: GFP mask to use | |
58 | */ | |
59 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
60 | { | |
61 | void *p; | |
62 | ||
1d2c8eea | 63 | p = kmalloc_track_caller(len, gfp); |
1a2f67b4 AD |
64 | if (p) |
65 | memcpy(p, src, len); | |
66 | return p; | |
67 | } | |
68 | EXPORT_SYMBOL(kmemdup); | |
69 | ||
ef2ad80c | 70 | /** |
93bc4e89 | 71 | * __krealloc - like krealloc() but don't free @p. |
ef2ad80c CL |
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 | * | |
93bc4e89 PE |
76 | * This function is like krealloc() except it never frees the originally |
77 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
78 | * like, for example, with RCU. | |
ef2ad80c | 79 | */ |
93bc4e89 | 80 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) |
ef2ad80c CL |
81 | { |
82 | void *ret; | |
ef8b4520 | 83 | size_t ks = 0; |
ef2ad80c | 84 | |
93bc4e89 | 85 | if (unlikely(!new_size)) |
6cb8f913 | 86 | return ZERO_SIZE_PTR; |
ef2ad80c | 87 | |
ef8b4520 CL |
88 | if (p) |
89 | ks = ksize(p); | |
90 | ||
ef2ad80c CL |
91 | if (ks >= new_size) |
92 | return (void *)p; | |
93 | ||
94 | ret = kmalloc_track_caller(new_size, flags); | |
93bc4e89 | 95 | if (ret && p) |
be21f0ab | 96 | memcpy(ret, p, ks); |
93bc4e89 PE |
97 | |
98 | return ret; | |
99 | } | |
100 | EXPORT_SYMBOL(__krealloc); | |
101 | ||
102 | /** | |
103 | * krealloc - reallocate memory. The contents will remain unchanged. | |
104 | * @p: object to reallocate memory for. | |
105 | * @new_size: how many bytes of memory are required. | |
106 | * @flags: the type of memory to allocate. | |
107 | * | |
108 | * The contents of the object pointed to are preserved up to the | |
109 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
110 | * behaves exactly like kmalloc(). If @size is 0 and @p is not a | |
111 | * %NULL pointer, the object pointed to is freed. | |
112 | */ | |
113 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
114 | { | |
115 | void *ret; | |
116 | ||
117 | if (unlikely(!new_size)) { | |
ef2ad80c | 118 | kfree(p); |
93bc4e89 | 119 | return ZERO_SIZE_PTR; |
ef2ad80c | 120 | } |
93bc4e89 PE |
121 | |
122 | ret = __krealloc(p, new_size, flags); | |
123 | if (ret && p != ret) | |
124 | kfree(p); | |
125 | ||
ef2ad80c CL |
126 | return ret; |
127 | } | |
128 | EXPORT_SYMBOL(krealloc); | |
129 | ||
96840aa0 DA |
130 | /* |
131 | * strndup_user - duplicate an existing string from user space | |
96840aa0 DA |
132 | * @s: The string to duplicate |
133 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
134 | */ | |
135 | char *strndup_user(const char __user *s, long n) | |
136 | { | |
137 | char *p; | |
138 | long length; | |
139 | ||
140 | length = strnlen_user(s, n); | |
141 | ||
142 | if (!length) | |
143 | return ERR_PTR(-EFAULT); | |
144 | ||
145 | if (length > n) | |
146 | return ERR_PTR(-EINVAL); | |
147 | ||
148 | p = kmalloc(length, GFP_KERNEL); | |
149 | ||
150 | if (!p) | |
151 | return ERR_PTR(-ENOMEM); | |
152 | ||
153 | if (copy_from_user(p, s, length)) { | |
154 | kfree(p); | |
155 | return ERR_PTR(-EFAULT); | |
156 | } | |
157 | ||
158 | p[length - 1] = '\0'; | |
159 | ||
160 | return p; | |
161 | } | |
162 | EXPORT_SYMBOL(strndup_user); |