Magisk/native/jni/magiskboot/dtb.cpp
2019-09-20 03:05:14 -04:00

180 lines
3.9 KiB
C++

#include <unistd.h>
#include <sys/mman.h>
extern "C" {
#include <libfdt.h>
}
#include <utils.h>
#include <bitset>
#include "magiskboot.h"
#include "format.h"
using namespace std;
constexpr int MAX_DEPTH = 32;
static bitset<MAX_DEPTH> depth_set;
static void pretty_node(int depth) {
if (depth == 0)
return;
for (int i = 0; i < depth - 1; ++i) {
if (depth_set[i])
printf("");
else
printf(" ");
}
if (depth_set[depth - 1])
printf("├── ");
else
printf("└── ");
}
static void pretty_prop(int depth) {
for (int i = 0; i < depth; ++i) {
if (depth_set[i])
printf("");
else
printf(" ");
}
if (depth_set[depth])
printf("");
else
printf(" ");
}
static void print_node(const void *fdt, int node = 0, int depth = 0) {
// Print node itself
pretty_node(depth);
printf("#%d: %s\n", node, fdt_get_name(fdt, node, nullptr));
// Print properties
depth_set[depth] = fdt_first_subnode(fdt, node) >= 0;
int prop;
fdt_for_each_property_offset(prop, fdt, node) {
pretty_prop(depth);
int size;
const char *name;
auto value = static_cast<const char *>(fdt_getprop_by_offset(fdt, prop, &name, &size));
bool is_str = !(size > 1 && value[0] == 0);
if (is_str) {
// Scan through value to see if printable
for (int i = 0; i < size; ++i) {
char c = value[i];
if (i == size - 1) {
// Make sure null terminate
is_str = c == '\0';
} else if ((c > 0 && c < 32) || c >= 127) {
is_str = false;
break;
}
}
}
if (is_str) {
printf("[%s]: [%s]\n", name, value);
} else {
printf("[%s]: <bytes>(%d)\n", name, size);
}
}
// Recursive
if (depth_set[depth]) {
int child;
int prev = -1;
fdt_for_each_subnode(child, fdt, node) {
if (prev >= 0)
print_node(fdt, prev, depth + 1);
prev = child;
}
depth_set[depth] = false;
print_node(fdt, prev, depth + 1);
}
}
static int find_fstab(const void *fdt, int parent) {
int node, fstab;
fdt_for_each_subnode(node, fdt, parent) {
if (strcmp(fdt_get_name(fdt, node, nullptr), "fstab") == 0)
return node;
fstab = find_fstab(fdt, node);
if (fstab != -1)
return fstab;
}
return -1;
}
static void dtb_dump(const char *file) {
size_t size ;
uint8_t *dtb, *fdt;
fprintf(stderr, "Loading dtbs from [%s]\n", file);
mmap_ro(file, dtb, size);
// Loop through all the dtbs
int dtb_num = 0;
for (int i = 0; i < size; ++i) {
if (memcmp(dtb + i, DTB_MAGIC, 4) == 0) {
fdt = dtb + i;
fprintf(stderr, "Dumping dtb.%04d\n", dtb_num++);
print_node(fdt);
}
}
fprintf(stderr, "\n");
munmap(dtb, size);
exit(0);
}
static void dtb_patch(const char *file, int patch) {
size_t size ;
uint8_t *dtb, *fdt;
fprintf(stderr, "Loading dtbs from [%s]\n", file);
if (patch)
mmap_rw(file, dtb, size);
else
mmap_ro(file, dtb, size);
// Loop through all the dtbs
int dtb_num = 0;
bool found = false;
for (int i = 0; i < size; ++i) {
if (memcmp(dtb + i, DTB_MAGIC, 4) == 0) {
fdt = dtb + i;
int fstab = find_fstab(fdt, 0);
if (fstab > 0) {
fprintf(stderr, "Found fstab in dtb.%04d\n", dtb_num++);
int block;
fdt_for_each_subnode(block, fdt, fstab) {
fprintf(stderr, "Found block [%s] in fstab\n", fdt_get_name(fdt, block, nullptr));
uint32_t value_size;
void *value = (void *) fdt_getprop(fdt, block, "fsmgr_flags", (int *)&value_size);
if (patch) {
void *dup = xmalloc(value_size);
memcpy(dup, value, value_size);
memset(value, 0, value_size);
found |= patch_verity(&dup, &value_size);
memcpy(value, dup, value_size);
free(dup);
} else {
found |= patch_verity(&value, &value_size, false);
}
}
}
}
}
munmap(dtb, size);
exit(!found);
}
int dtb_commands(const char *cmd, int argc, char *argv[]) {
if (argc == 0) return 1;
if (strcmp(cmd, "dump") == 0)
dtb_dump(argv[0]);
else if (strcmp(cmd, "patch") == 0)
dtb_patch(argv[0], 1);
else if (strcmp(cmd, "test") == 0)
dtb_patch(argv[0], 0);
return 0;
}