我正在尝试理解如何使用/proc/pid/pagemap获取给定页的物理地址。假设从/proc/pid/maps中,我得到了虚拟地址afa2d000-afa42000,它对应于堆。我的问题是如何使用这些信息遍历pagemap文件并找到与地址afa2d000-afa42000相对应的物理页面帧。
/proc/pid/pagemap条目以二进制格式存储。是否有任何工具可用来帮助解析此文件?
我正在尝试理解如何使用/proc/pid/pagemap获取给定页的物理地址。假设从/proc/pid/maps中,我得到了虚拟地址afa2d000-afa42000,它对应于堆。我的问题是如何使用这些信息遍历pagemap文件并找到与地址afa2d000-afa42000相对应的物理页面帧。
/proc/pid/pagemap条目以二进制格式存储。是否有任何工具可用来帮助解析此文件?
Linux内核文档
Linux内核文档描述了格式:https://github.com/torvalds/linux/blob/v4.9/Documentation/vm/pagemap.txt
* Bits 0-54 page frame number (PFN) if present
* Bits 0-4 swap type if swapped
* Bits 5-54 swap offset if swapped
* Bit 55 pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
* Bit 56 page exclusively mapped (since 4.2)
* Bits 57-60 zero
* Bit 61 page is file-page or shared-anon (since 3.5)
* Bit 62 page swapped
* Bit 63 page present
#define _XOPEN_SOURCE 700
#include <fcntl.h> /* open */
#include <stdint.h> /* uint64_t */
#include <stdlib.h> /* size_t */
#include <unistd.h> /* pread, sysconf */
typedef struct {
uint64_t pfn : 54;
unsigned int soft_dirty : 1;
unsigned int file_page : 1;
unsigned int swapped : 1;
unsigned int present : 1;
} PagemapEntry;
/* Parse the pagemap entry for the given virtual address.
*
* @param[out] entry the parsed entry
* @param[in] pagemap_fd file descriptor to an open /proc/pid/pagemap file
* @param[in] vaddr virtual address to get entry for
* @return 0 for success, 1 for failure
*/
int pagemap_get_entry(PagemapEntry *entry, int pagemap_fd, uintptr_t vaddr)
{
size_t nread;
ssize_t ret;
uint64_t data;
nread = 0;
while (nread < sizeof(data)) {
ret = pread(pagemap_fd, ((uint8_t*)&data) + nread, sizeof(data) - nread,
(vaddr / sysconf(_SC_PAGE_SIZE)) * sizeof(data) + nread);
nread += ret;
if (ret <= 0) {
return 1;
}
}
entry->pfn = data & (((uint64_t)1 << 54) - 1);
entry->soft_dirty = (data >> 54) & 1;
entry->file_page = (data >> 61) & 1;
entry->swapped = (data >> 62) & 1;
entry->present = (data >> 63) & 1;
return 0;
}
使用它的示例可运行程序:
我希望这个链接能够帮到你。这是一个非常简单的工具,确定你需要访问的地址也很简单: http://fivelinesofcode.blogspot.com/2014/03/how-to-translate-virtual-to-physical.html
page-analyze.cpp: 在函数‘void make_short_name(char*, const char*)’中: page-analyze.cpp:135:35: 错误:将只读位置‘* strchr(b, 93)’赋值 make: *** [page-analyze] Error 1
。 - JohnnyFromBF如果有人想用Rust来实现,我已经添加了一个Rust实现,这样你就可以轻松地浏览/proc/$pid/maps
和/proc/$pid/pagemap
:https://crates.io/crates/vm-info