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- /* https://cirosantilli.com/linux-kernel-module-cheat#pagemap-dump-out */
- #define _XOPEN_SOURCE 700
- #include <errno.h>
- #include <fcntl.h>
- #include <stdint.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <sys/types.h>
- #include <unistd.h>
- #include <lkmc/pagemap.h> /* lkmc_pagemap_virt_to_phys_user */
- int main(int argc, char **argv) {
- char buffer[BUFSIZ];
- char maps_file[BUFSIZ];
- char pagemap_file[BUFSIZ];
- int maps_fd;
- int offset = 0;
- int pagemap_fd;
- pid_t pid;
- if (argc < 2) {
- printf("Usage: %s pid\n", argv[0]);
- return EXIT_FAILURE;
- }
- pid = strtoull(argv[1], NULL, 0);
- snprintf(maps_file, sizeof(maps_file), "/proc/%ju/maps", (uintmax_t)pid);
- snprintf(pagemap_file, sizeof(pagemap_file), "/proc/%ju/pagemap", (uintmax_t)pid);
- maps_fd = open(maps_file, O_RDONLY);
- if (maps_fd < 0) {
- perror("open maps");
- return EXIT_FAILURE;
- }
- pagemap_fd = open(pagemap_file, O_RDONLY);
- if (pagemap_fd < 0) {
- perror("open pagemap");
- return EXIT_FAILURE;
- }
- printf("vaddr pfn soft-dirty file/shared swapped present library\n");
- for (;;) {
- ssize_t length = read(maps_fd, buffer + offset, sizeof buffer - offset);
- if (length <= 0) break;
- length += offset;
- for (size_t i = offset; i < (size_t)length; i++) {
- uintptr_t low = 0, high = 0;
- if (buffer[i] == '\n' && i) {
- const char *lib_name;
- size_t y;
- /* Parse a line from maps. Each line contains a range that contains many pages. */
- {
- size_t x = i - 1;
- while (x && buffer[x] != '\n') x--;
- if (buffer[x] == '\n') x++;
- while (buffer[x] != '-' && x < sizeof buffer) {
- char c = buffer[x++];
- low *= 16;
- if (c >= '0' && c <= '9') {
- low += c - '0';
- } else if (c >= 'a' && c <= 'f') {
- low += c - 'a' + 10;
- } else {
- break;
- }
- }
- while (buffer[x] != '-' && x < sizeof buffer) x++;
- if (buffer[x] == '-') x++;
- while (buffer[x] != ' ' && x < sizeof buffer) {
- char c = buffer[x++];
- high *= 16;
- if (c >= '0' && c <= '9') {
- high += c - '0';
- } else if (c >= 'a' && c <= 'f') {
- high += c - 'a' + 10;
- } else {
- break;
- }
- }
- lib_name = 0;
- for (int field = 0; field < 4; field++) {
- x++;
- while(buffer[x] != ' ' && x < sizeof buffer) x++;
- }
- while (buffer[x] == ' ' && x < sizeof buffer) x++;
- y = x;
- while (buffer[y] != '\n' && y < sizeof buffer) y++;
- buffer[y] = 0;
- lib_name = buffer + x;
- }
- /* Get info about all pages in this page range with pagemap. */
- {
- LkmcPagemapEntry entry;
- for (uintptr_t vaddr = low; vaddr < high; vaddr += sysconf(_SC_PAGE_SIZE)) {
- /* TODO always fails for the last page (vsyscall), why? pread returns 0. */
- if (!lkmc_pagemap_get_entry(&entry, pagemap_fd, vaddr)) {
- printf(
- "%jx %jx %u %u %u %u %s\n",
- (uintmax_t)vaddr,
- (uintmax_t)entry.pfn,
- entry.soft_dirty,
- entry.file_page,
- entry.swapped,
- entry.present,
- lib_name
- );
- }
- }
- }
- buffer[y] = '\n';
- }
- }
- }
- close(maps_fd);
- close(pagemap_fd);
- return EXIT_SUCCESS;
- }
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