| 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 |