Commit | Line | Data |
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16d69265 | 1 | #include <linux/mm.h> |
30992c97 MM |
2 | #include <linux/slab.h> |
3 | #include <linux/string.h> | |
4 | #include <linux/module.h> | |
96840aa0 | 5 | #include <linux/err.h> |
3b8f14b4 | 6 | #include <linux/sched.h> |
96840aa0 | 7 | #include <asm/uaccess.h> |
30992c97 MM |
8 | |
9 | /** | |
30992c97 | 10 | * kstrdup - allocate space for and copy an existing string |
30992c97 MM |
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; | |
1d2c8eea | 23 | buf = kmalloc_track_caller(len, gfp); |
30992c97 MM |
24 | if (buf) |
25 | memcpy(buf, s, len); | |
26 | return buf; | |
27 | } | |
28 | EXPORT_SYMBOL(kstrdup); | |
96840aa0 | 29 | |
1e66df3e JF |
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 | ||
1a2f67b4 AD |
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 | ||
1d2c8eea | 65 | p = kmalloc_track_caller(len, gfp); |
1a2f67b4 AD |
66 | if (p) |
67 | memcpy(p, src, len); | |
68 | return p; | |
69 | } | |
70 | EXPORT_SYMBOL(kmemdup); | |
71 | ||
610a77e0 LZ |
72 | /** |
73 | * memdup_user - duplicate memory region from user space | |
74 | * | |
75 | * @src: source address in user space | |
76 | * @len: number of bytes to copy | |
77 | * | |
78 | * Returns an ERR_PTR() on failure. | |
79 | */ | |
80 | void *memdup_user(const void __user *src, size_t len) | |
81 | { | |
82 | void *p; | |
83 | ||
84 | /* | |
85 | * Always use GFP_KERNEL, since copy_from_user() can sleep and | |
86 | * cause pagefault, which makes it pointless to use GFP_NOFS | |
87 | * or GFP_ATOMIC. | |
88 | */ | |
89 | p = kmalloc_track_caller(len, GFP_KERNEL); | |
90 | if (!p) | |
91 | return ERR_PTR(-ENOMEM); | |
92 | ||
93 | if (copy_from_user(p, src, len)) { | |
94 | kfree(p); | |
95 | return ERR_PTR(-EFAULT); | |
96 | } | |
97 | ||
98 | return p; | |
99 | } | |
100 | EXPORT_SYMBOL(memdup_user); | |
101 | ||
ef2ad80c | 102 | /** |
93bc4e89 | 103 | * __krealloc - like krealloc() but don't free @p. |
ef2ad80c CL |
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 | * | |
93bc4e89 PE |
108 | * This function is like krealloc() except it never frees the originally |
109 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
110 | * like, for example, with RCU. | |
ef2ad80c | 111 | */ |
93bc4e89 | 112 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) |
ef2ad80c CL |
113 | { |
114 | void *ret; | |
ef8b4520 | 115 | size_t ks = 0; |
ef2ad80c | 116 | |
93bc4e89 | 117 | if (unlikely(!new_size)) |
6cb8f913 | 118 | return ZERO_SIZE_PTR; |
ef2ad80c | 119 | |
ef8b4520 CL |
120 | if (p) |
121 | ks = ksize(p); | |
122 | ||
ef2ad80c CL |
123 | if (ks >= new_size) |
124 | return (void *)p; | |
125 | ||
126 | ret = kmalloc_track_caller(new_size, flags); | |
93bc4e89 | 127 | if (ret && p) |
be21f0ab | 128 | memcpy(ret, p, ks); |
93bc4e89 PE |
129 | |
130 | return ret; | |
131 | } | |
132 | EXPORT_SYMBOL(__krealloc); | |
133 | ||
134 | /** | |
135 | * krealloc - reallocate memory. The contents will remain unchanged. | |
136 | * @p: object to reallocate memory for. | |
137 | * @new_size: how many bytes of memory are required. | |
138 | * @flags: the type of memory to allocate. | |
139 | * | |
140 | * The contents of the object pointed to are preserved up to the | |
141 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
142 | * behaves exactly like kmalloc(). If @size is 0 and @p is not a | |
143 | * %NULL pointer, the object pointed to is freed. | |
144 | */ | |
145 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
146 | { | |
147 | void *ret; | |
148 | ||
149 | if (unlikely(!new_size)) { | |
ef2ad80c | 150 | kfree(p); |
93bc4e89 | 151 | return ZERO_SIZE_PTR; |
ef2ad80c | 152 | } |
93bc4e89 PE |
153 | |
154 | ret = __krealloc(p, new_size, flags); | |
155 | if (ret && p != ret) | |
156 | kfree(p); | |
157 | ||
ef2ad80c CL |
158 | return ret; |
159 | } | |
160 | EXPORT_SYMBOL(krealloc); | |
161 | ||
3ef0e5ba JW |
162 | /** |
163 | * kzfree - like kfree but zero memory | |
164 | * @p: object to free memory of | |
165 | * | |
166 | * The memory of the object @p points to is zeroed before freed. | |
167 | * If @p is %NULL, kzfree() does nothing. | |
168 | */ | |
169 | void kzfree(const void *p) | |
170 | { | |
171 | size_t ks; | |
172 | void *mem = (void *)p; | |
173 | ||
174 | if (unlikely(ZERO_OR_NULL_PTR(mem))) | |
175 | return; | |
176 | ks = ksize(mem); | |
177 | memset(mem, 0, ks); | |
178 | kfree(mem); | |
179 | } | |
180 | EXPORT_SYMBOL(kzfree); | |
181 | ||
96840aa0 DA |
182 | /* |
183 | * strndup_user - duplicate an existing string from user space | |
96840aa0 DA |
184 | * @s: The string to duplicate |
185 | * @n: Maximum number of bytes to copy, including the trailing NUL. | |
186 | */ | |
187 | char *strndup_user(const char __user *s, long n) | |
188 | { | |
189 | char *p; | |
190 | long length; | |
191 | ||
192 | length = strnlen_user(s, n); | |
193 | ||
194 | if (!length) | |
195 | return ERR_PTR(-EFAULT); | |
196 | ||
197 | if (length > n) | |
198 | return ERR_PTR(-EINVAL); | |
199 | ||
200 | p = kmalloc(length, GFP_KERNEL); | |
201 | ||
202 | if (!p) | |
203 | return ERR_PTR(-ENOMEM); | |
204 | ||
205 | if (copy_from_user(p, s, length)) { | |
206 | kfree(p); | |
207 | return ERR_PTR(-EFAULT); | |
208 | } | |
209 | ||
210 | p[length - 1] = '\0'; | |
211 | ||
212 | return p; | |
213 | } | |
214 | EXPORT_SYMBOL(strndup_user); | |
16d69265 AM |
215 | |
216 | #ifndef HAVE_ARCH_PICK_MMAP_LAYOUT | |
217 | void arch_pick_mmap_layout(struct mm_struct *mm) | |
218 | { | |
219 | mm->mmap_base = TASK_UNMAPPED_BASE; | |
220 | mm->get_unmapped_area = arch_get_unmapped_area; | |
221 | mm->unmap_area = arch_unmap_area; | |
222 | } | |
223 | #endif | |
912985dc RR |
224 | |
225 | int __attribute__((weak)) get_user_pages_fast(unsigned long start, | |
226 | int nr_pages, int write, struct page **pages) | |
227 | { | |
228 | struct mm_struct *mm = current->mm; | |
229 | int ret; | |
230 | ||
231 | down_read(&mm->mmap_sem); | |
232 | ret = get_user_pages(current, mm, start, nr_pages, | |
233 | write, 0, pages, NULL); | |
234 | up_read(&mm->mmap_sem); | |
235 | ||
236 | return ret; | |
237 | } | |
238 | EXPORT_SYMBOL_GPL(get_user_pages_fast); |