mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-23 18:25:57 +01:00
56738a1c70
Unsquashed version at v2-rc-unsquashed, but that cannot be merged as it breaks bisects at several points. All bugs will not bisect to this humongous change. It all started with a conversion of the Bash scripts to Python, mainly because I couldn't stand not being able to properly use --options for run which has a million options. Then since that required a full testing, I decided to do all the refactorings that I had in mind at once, and so I did and it became v2-rc. This is the largest patch I have ever done! OMG a few weeks of extra time. I'm never writing a Bash script for anything that starts getting big again. Some of the features are: * separate build-qemu and build-gem5 commands * common: convert scripts to python. Add --option for everything * rename build to build-buildroot now that we are splitting all the build commands, Linux kernel to follow * move all git submodules to submodules/ and all buildroot packages to packages/ * refactor the out/ structure. Keep projects on toplevel, because guest projects separate archs and host ones don't, making a toplevel arch wrong * do-release: rename to just release https://stackoverflow.com/questions/16174992/cant-get-argparse-to-read-quoted-string-with-dashes-in-it * run: add --terminal and explain gem5 pdb * just track the lvimrc * store CLI kernel config fragment inside buildlroot to avoid conflicts * gem5: document m5 initparam * readme: make a bunch of things awesomer * readme: fix broken refs * parsec-benchmark: update to 75d55ac446a43c47efb1044844a108c6c330184c Could not fetch otherwise. * gem5: M5_OVERRIDE_PY_SOURCE
95 lines
2.4 KiB
C
95 lines
2.4 KiB
C
/* https://github.com/cirosantilli/linux-kernel-module-cheat#mmap */
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#define _XOPEN_SOURCE 700
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#include <assert.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h> /* uintmax_t */
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#include <string.h>
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#include <sys/mman.h>
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#include <unistd.h> /* sysconf */
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#include "common.h" /* virt_to_phys_user */
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enum { BUFFER_SIZE = 4 };
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int main(int argc, char **argv)
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{
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int fd;
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long page_size;
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char *address1, *address2;
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char buf[BUFFER_SIZE];
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uintptr_t paddr;
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if (argc < 2) {
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printf("Usage: %s <mmap_file>\n", argv[0]);
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return EXIT_FAILURE;
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}
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page_size = sysconf(_SC_PAGE_SIZE);
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printf("open pathname = %s\n", argv[1]);
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fd = open(argv[1], O_RDWR | O_SYNC);
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if (fd < 0) {
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perror("open");
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assert(0);
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}
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printf("fd = %d\n", fd);
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/* mmap twice for double fun. */
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puts("mmap 1");
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address1 = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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if (address1 == MAP_FAILED) {
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perror("mmap");
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assert(0);
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}
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puts("mmap 2");
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address2 = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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if (address2 == MAP_FAILED) {
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perror("mmap");
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return EXIT_FAILURE;
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}
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assert(address1 != address2);
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/* Read and modify memory. */
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puts("access 1");
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assert(!strcmp(address1, "asdf"));
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/* vm_fault */
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puts("access 2");
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assert(!strcmp(address2, "asdf"));
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/* vm_fault */
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strcpy(address1, "qwer");
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/* Also modified. So both virtual addresses point to the same physical address. */
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assert(!strcmp(address2, "qwer"));
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/* Check that the physical addresses are the same.
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* They are, but TODO why virt_to_phys on kernel gives a different value? */
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assert(!virt_to_phys_user(&paddr, getpid(), (uintptr_t)address1));
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printf("paddr1 = 0x%jx\n", (uintmax_t)paddr);
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assert(!virt_to_phys_user(&paddr, getpid(), (uintptr_t)address2));
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printf("paddr2 = 0x%jx\n", (uintmax_t)paddr);
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/* Check that modifications made from userland are also visible from the kernel. */
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read(fd, buf, BUFFER_SIZE);
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assert(!memcmp(buf, "qwer", BUFFER_SIZE));
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/* Modify the data from the kernel, and check that the change is visible from userland. */
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write(fd, "zxcv", 4);
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assert(!strcmp(address1, "zxcv"));
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assert(!strcmp(address2, "zxcv"));
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/* Cleanup. */
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puts("munmap 1");
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if (munmap(address1, page_size)) {
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perror("munmap");
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assert(0);
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}
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puts("munmap 2");
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if (munmap(address2, page_size)) {
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perror("munmap");
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assert(0);
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}
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puts("close");
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close(fd);
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return EXIT_SUCCESS;
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}
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