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1 | #include <linux/mm.h> | |
2 | #include <linux/slab.h> | |
3 | #include <linux/string.h> | |
4 | #include <linux/module.h> | |
5 | #include <linux/err.h> | |
6 | #include <linux/sched.h> | |
7 | #include <asm/uaccess.h> | |
8 | ||
9 | /** | |
10 | * kstrdup - allocate space for and copy an existing string | |
11 | * @s: the string to duplicate | |
12 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
13 | */ | |
14 | char *kstrdup(const char *s, gfp_t gfp) | |
15 | { | |
16 | size_t len; | |
17 | char *buf; | |
18 | ||
19 | if (!s) | |
20 | return NULL; | |
21 | ||
22 | len = strlen(s) + 1; | |
23 | buf = kmalloc_track_caller(len, gfp); | |
24 | if (buf) | |
25 | memcpy(buf, s, len); | |
26 | return buf; | |
27 | } | |
28 | EXPORT_SYMBOL(kstrdup); | |
29 | ||
30 | /** | |
31 | * kstrndup - allocate space for and copy an existing string | |
32 | * @s: the string to duplicate | |
33 | * @max: read at most @max chars from @s | |
34 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory | |
35 | */ | |
36 | char *kstrndup(const char *s, size_t max, gfp_t gfp) | |
37 | { | |
38 | size_t len; | |
39 | char *buf; | |
40 | ||
41 | if (!s) | |
42 | return NULL; | |
43 | ||
44 | len = strnlen(s, max); | |
45 | buf = kmalloc_track_caller(len+1, gfp); | |
46 | if (buf) { | |
47 | memcpy(buf, s, len); | |
48 | buf[len] = '\0'; | |
49 | } | |
50 | return buf; | |
51 | } | |
52 | EXPORT_SYMBOL(kstrndup); | |
53 | ||
54 | /** | |
55 | * kmemdup - duplicate region of memory | |
56 | * | |
57 | * @src: memory region to duplicate | |
58 | * @len: memory region length | |
59 | * @gfp: GFP mask to use | |
60 | */ | |
61 | void *kmemdup(const void *src, size_t len, gfp_t gfp) | |
62 | { | |
63 | void *p; | |
64 | ||
65 | p = kmalloc_track_caller(len, gfp); | |
66 | if (p) | |
67 | memcpy(p, src, len); | |
68 | return p; | |
69 | } | |
70 | EXPORT_SYMBOL(kmemdup); | |
71 | ||
72 | /** | |
73 | * __krealloc - like krealloc() but don't free @p. | |
74 | * @p: object to reallocate memory for. | |
75 | * @new_size: how many bytes of memory are required. | |
76 | * @flags: the type of memory to allocate. | |
77 | * | |
78 | * This function is like krealloc() except it never frees the originally | |
79 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
80 | * like, for example, with RCU. | |
81 | */ | |
82 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) | |
83 | { | |
84 | void *ret; | |
85 | size_t ks = 0; | |
86 | ||
87 | if (unlikely(!new_size)) | |
88 | return ZERO_SIZE_PTR; | |
89 | ||
90 | if (p) | |
91 | ks = ksize(p); | |
92 | ||
93 | if (ks >= new_size) | |
94 | return (void *)p; | |
95 | ||
96 | ret = kmalloc_track_caller(new_size, flags); | |
97 | if (ret && p) | |
98 | memcpy(ret, p, ks); | |
99 | ||
100 | return ret; | |
101 | } | |
102 | EXPORT_SYMBOL(__krealloc); | |
103 | ||
104 | /** | |
105 | * krealloc - reallocate memory. The contents will remain unchanged. | |
106 | * @p: object to reallocate memory for. | |
107 | * @new_size: how many bytes of memory are required. | |
108 | * @flags: the type of memory to allocate. | |
109 | * | |
110 | * The contents of the object pointed to are preserved up to the | |
111 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
112 | * behaves exactly like kmalloc(). If @size is 0 and @p is not a | |
113 | * %NULL pointer, the object pointed to is freed. | |
114 | */ | |
115 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
116 | { | |
117 | void *ret; | |
118 | ||
119 | if (unlikely(!new_size)) { | |
120 | kfree(p); | |
121 | return ZERO_SIZE_PTR; | |
122 | } | |
123 | ||
124 | ret = __krealloc(p, new_size, flags); | |
125 | if (ret && p != ret) | |
126 | kfree(p); | |
127 | ||
128 | return ret; | |
129 | } | |
130 | EXPORT_SYMBOL(krealloc); | |
131 | ||
132 | /* | |
133 | * strndup_user - duplicate an existing string from user space | |
134 | * @s: The string to duplicate | |
135 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
136 | */ | |
137 | char *strndup_user(const char __user *s, long n) | |
138 | { | |
139 | char *p; | |
140 | long length; | |
141 | ||
142 | length = strnlen_user(s, n); | |
143 | ||
144 | if (!length) | |
145 | return ERR_PTR(-EFAULT); | |
146 | ||
147 | if (length > n) | |
148 | return ERR_PTR(-EINVAL); | |
149 | ||
150 | p = kmalloc(length, GFP_KERNEL); | |
151 | ||
152 | if (!p) | |
153 | return ERR_PTR(-ENOMEM); | |
154 | ||
155 | if (copy_from_user(p, s, length)) { | |
156 | kfree(p); | |
157 | return ERR_PTR(-EFAULT); | |
158 | } | |
159 | ||
160 | p[length - 1] = '\0'; | |
161 | ||
162 | return p; | |
163 | } | |
164 | EXPORT_SYMBOL(strndup_user); | |
165 | ||
166 | #ifndef HAVE_ARCH_PICK_MMAP_LAYOUT | |
167 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
168 | { | |
169 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
170 | mm->get_unmapped_area = arch_get_unmapped_area; | |
171 | mm->unmap_area = arch_unmap_area; | |
172 | } | |
173 | #endif |