#include <linux/slab.h> #include <linux/string.h> #include <linux/module.h> #include <linux/err.h> #include <asm/uaccess.h> /** * kstrdup - allocate space for and copy an existing string * @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory */ char *kstrdup(const char *s, gfp_t gfp) { size_t len; char *buf; if (!s) return NULL; len = strlen(s) + 1; buf = kmalloc_track_caller(len, gfp); if (buf) memcpy(buf, s, len); return buf; } EXPORT_SYMBOL(kstrdup); /** * kstrndup - allocate space for and copy an existing string * @s: the string to duplicate * @max: read at most @max chars from @s * @gfp: the GFP mask used in the kmalloc() call when allocating memory */ char *kstrndup(const char *s, size_t max, gfp_t gfp) { size_t len; char *buf; if (!s) return NULL; len = strnlen(s, max); buf = kmalloc_track_caller(len+1, gfp); if (buf) { memcpy(buf, s, len); buf[len] = '\0'; } return buf; } EXPORT_SYMBOL(kstrndup); /** * kmemdup - duplicate region of memory * * @src: memory region to duplicate * @len: memory region length * @gfp: GFP mask to use */ void *kmemdup(const void *src, size_t len, gfp_t gfp) { void *p; p = kmalloc_track_caller(len, gfp); if (p) memcpy(p, src, len); return p; } EXPORT_SYMBOL(kmemdup); /** * krealloc - reallocate memory. The contents will remain unchanged. * @p: object to reallocate memory for. * @new_size: how many bytes of memory are required. * @flags: the type of memory to allocate. * * The contents of the object pointed to are preserved up to the * lesser of the new and old sizes. If @p is %NULL, krealloc() * behaves exactly like kmalloc(). If @size is 0 and @p is not a * %NULL pointer, the object pointed to is freed. */ void *krealloc(const void *p, size_t new_size, gfp_t flags) { void *ret; size_t ks; if (unlikely(!new_size)) { kfree(p); return ZERO_SIZE_PTR; } ks = ksize(p); if (ks >= new_size) return (void *)p; ret = kmalloc_track_caller(new_size, flags); if (ret) { memcpy(ret, p, min(new_size, ks)); kfree(p); } return ret; } EXPORT_SYMBOL(krealloc); /* * strndup_user - duplicate an existing string from user space * @s: The string to duplicate * @n: Maximum number of bytes to copy, including the trailing NUL. */ char *strndup_user(const char __user *s, long n) { char *p; long length; length = strnlen_user(s, n); if (!length) return ERR_PTR(-EFAULT); if (length > n) return ERR_PTR(-EINVAL); p = kmalloc(length, GFP_KERNEL); if (!p) return ERR_PTR(-ENOMEM); if (copy_from_user(p, s, length)) { kfree(p); return ERR_PTR(-EFAULT); } p[length - 1] = '\0'; return p; } EXPORT_SYMBOL(strndup_user);