3rd-party/linux-kernel-module-cheat
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move doc of userland physical address tests to README

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Ciro Santilli
2018-07-10 13:44:17 +01:00
parent 6045b9fa3d
commit d34a8a3e9f
7 changed files with 263 additions and 148 deletions
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35
kernel_module/user/pagemap_dump.c
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@@ -1,29 +1,4 @@
/*
Only tested in x86_64.
Adapted from: https://github.com/dwks/pagemap/blob/8a25747bc79d6080c8b94eac80807a4dceeda57a/pagemap2.c
- https://stackoverflow.com/questions/17021214/how-to-decode-proc-pid-pagemap-entries-in-linux/45126141#45126141
- https://stackoverflow.com/questions/5748492/is-there-any-api-for-determining-the-physical-address-from-virtual-address-in-li
- https://stackoverflow.com/questions/6284810/proc-pid-pagemaps-and-proc-pid-maps-linux/45500208#45500208
Dump the page map of a given process PID.
Data sources: /proc/PIC/{map,pagemap}
This program works in two steps:
- parse the human readable lines lines from `/proc/<pid>/maps`. This files contains lines of form:
7ffff7b6d000-7ffff7bdd000 r-xp 00000000 fe:00 658 /lib/libuClibc-1.0.22.so
which gives us:
- `7f8af99f8000-7f8af99ff000`: a virtual address range that belong to the process, possibly containing multiple pages.
- `/lib/libuClibc-1.0.22.so` the name of the library that owns that memory.
- loop over each page of each address range, and ask `/proc/<pid>/pagemap` for more information about that page, including the physical address.
*/
/* https://github.com/cirosantilli/linux-kernel-module-cheat#pagemap_dump-out */
#define _XOPEN_SOURCE 700
#include <errno.h>
@@ -63,7 +38,7 @@ int main(int argc, char **argv)
perror("open pagemap");
return EXIT_FAILURE;
}
printf("addr pfn soft-dirty file/shared swapped present library\n");
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;
@@ -116,11 +91,11 @@ int main(int argc, char **argv)
/* Get info about all pages in this page range with pagemap. */
{
PagemapEntry entry;
for (uintptr_t addr = low; addr < high; addr += sysconf(_SC_PAGE_SIZE)) {
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 (!pagemap_get_entry(&entry, pagemap_fd, addr)) {
if (!pagemap_get_entry(&entry, pagemap_fd, vaddr)) {
printf("%jx %jx %u %u %u %u %s\n",
(uintmax_t)addr,
(uintmax_t)vaddr,
(uintmax_t)entry.pfn,
entry.soft_dirty,
entry.file_page,