Webcopy_from_user和copy_to_user就是用来保证内核态安全地访问（读和写）用户态内存空间。 copy_from_user/copy_to_user 的实现原理非常简单，如下： 1. 如果buf空间属于内核态空间，直接返回出错，不处理（这是解决上述场景3） 2. copy_from_user/copy_to_user使用精心布置的访存汇编实现，并指这个汇编指令所在 … Web28 jun. 2024 · 为什么不直接用memcpy？ 这个问题主要涉及到2个层面，一个是copy_from_user ()有自带的access_ok检查，如果用户传进来的buffer不属于用户空间而是内核空间，根本不会拷贝；二是copy_from_user ()有自带的page fault后exception修复机制。 先看第一个问题，如果代码直接用memcpy ()：
memcpy and copy_to/from_user - LinuxQuestions.org
Web9 sep. 2015 · 1 This question already has answers here: copy_to_user vs memcpy (2 answers) Closed 7 years ago. Let consider following code. For someone who read Linux … WebThe C library function void *memcpy(void *dest, const void *src, size_t n) copies n characters from memory area src to memory area dest. Declaration. Following is the … henthorn v. fraser
c - memcpy instead of copy_to_user - Stack Overflow
Web12 mrt. 2024 · copy_to_user identifier - Linux source code (v6.2.10) - Bootlin Elixir Cross Referencer - Explore source code in your browser - Particularly useful for the Linux kernel and other low-level projects in C/C++ (bootloaders, C libraries...) Linux debugging Check our new training course Linux debugging, tracing, profiling & perf. analysis Web2 jun. 2012 · 在从事Linux Kernel开发的过程中，user_app和kernel之间传递数据时不能使用memcpy ()函数，必须使用copy_to/from_kernel或者是put/get_user。 原因是kernel … Web5 nov. 2024 · Notes. memcpy may be used to set the effective type of an object obtained by an allocation function.. memcpy is the fastest library routine for memory-to-memory copy. It is usually more efficient than strcpy, which must scan the data it copies or memmove, which must take precautions to handle overlapping inputs.. Several C compilers transform … henthorn vanity