3rd-party/linux-kernel-module-cheat
1
0
Fork 0
mirror of https://github.com/cirosantilli/linux-kernel-module-cheat.git synced 2026-01-23 02:05:57 +01:00
Code Issues Releases Wiki Activity

devmem3 cleanup further

Browse Source
This commit is contained in:
Ciro Santilli
2017-08-05 21:24:16 +01:00
parent d871c008fb
commit c6edbfddb0
1 changed files with 30 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

57
kernel_module/user/devmem3.c
View File

@@ -1,33 +1,36 @@
/*
Adapted from: http://free-electrons.com/pub/mirror/devmem2.c
Forked because of the unpredictable access widths:
https://bugs.busybox.net/show_bug.cgi?id=10171
*/
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <stdint.h>
#include <sys/types.h>
#include <termios.h>
#include <unistd.h>
#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \
__LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)
#define MAP_SIZE 4096UL
#define MAP_MASK (MAP_SIZE - 1)
int main(int argc, char **argv) {
int fd;
void *map_base, *virt_addr;
uintmax_t read_result, writeval;
off_t target;
int access_type = 'w';
unsigned long map_size, map_mask;
off_t target;
uintmax_t read_result, writeval;
int fd;
void *map_base, *virt_addr;
map_size = sysconf(_SC_PAGE_SIZE);
map_mask = map_size - 1;
if(argc < 2) {
fprintf(stderr, "\nUsage:\t%s { address } [ type [ data ] ]\n"
"\taddress : memory address to act upon\n"
@@ -43,16 +46,16 @@ int main(int argc, char **argv) {
if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL;
printf("/dev/mem opened.\n");
printf("/dev/mem opened.\n");
fflush(stdout);
/* Map one page */
map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target & ~MAP_MASK);
map_base = mmap(0, map_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target & ~map_mask);
if(map_base == (void *) -1) FATAL;
printf("Memory mapped at address %p.\n", map_base);
printf("Memory mapped at address %p.\n", map_base);
fflush(stdout);
virt_addr = map_base + (target & MAP_MASK);
virt_addr = map_base + (target & map_mask);
switch(access_type) {
case 'b':
read_result = *((uint8_t *) virt_addr);
@@ -70,7 +73,7 @@ int main(int argc, char **argv) {
fprintf(stderr, "Illegal data type '%c'.\n", access_type);
exit(2);
}
printf("Value at address 0x%jX (%p): 0x%jX\n", (uintmax_t)target, virt_addr, (uintmax_t)read_result);
printf("Value at address 0x%jX (%p): 0x%jX\n", (uintmax_t)target, virt_addr, (uintmax_t)read_result);
fflush(stdout);
if(argc > 3) {
@@ -93,11 +96,11 @@ int main(int argc, char **argv) {
read_result = *((uint64_t *) virt_addr);
break;
}
printf("Written 0x%X; readback 0x%jX\n", (unsigned int)writeval, (unsigned int)read_result);
printf("Written 0x%jX; readback 0x%jX\n", (uintmax_t)writeval, (uintmax_t)read_result);
fflush(stdout);
}
if(munmap(map_base, MAP_SIZE) == -1) FATAL;
if(munmap(map_base, map_size) == -1) FATAL;
close(fd);
return 0;
}