Magisk/native/jni/inject/utils.cpp
topjohnwu 4060c2107c Add preliminary zygote code injection support
Prototyping the injection setup and a clean "self unloading" mechanism.
2021-01-06 22:21:17 -08:00

102 lines
2.5 KiB
C++

#include <utils.hpp>
#include "inject.hpp"
using namespace std;
namespace {
struct map_info {
uintptr_t start;
uintptr_t end;
int perms;
char *path;
map_info() : start(0), end(0), perms(0), path(nullptr) {}
enum {
EXEC = (1 << 0),
WRITE = (1 << 1),
READ = (1 << 2),
};
};
} // namespace
template<typename Func>
static void parse_maps(int pid, Func fn) {
char file[32];
// format: start-end perms offset dev inode path
sprintf(file, "/proc/%d/maps", pid);
file_readline(true, file, [=](string_view l) -> bool {
char *pos = (char *) l.data();
map_info info;
// Parse address hex strings
info.start = strtoul(pos, &pos, 16);
info.end = strtoul(++pos, &pos, 16);
// Parse permissions
if (*(++pos) != '-')
info.perms |= map_info::READ;
if (*(++pos) != '-')
info.perms |= map_info::WRITE;
if (*(++pos) != '-')
info.perms |= map_info::EXEC;
pos += 3;
// Skip everything except path
int path_off;
sscanf(pos, "%*s %*s %*s %n%*s", &path_off);
pos += path_off;
info.path = pos;
return fn(info);
});
}
void unmap_all(const char *name) {
vector<map_info> unmaps;
parse_maps(getpid(), [=, &unmaps](map_info &info) -> bool {
if (strcmp(info.path, name) == 0)
unmaps.emplace_back(info);
return true;
});
for (map_info &info : unmaps) {
void *addr = reinterpret_cast<void *>(info.start);
size_t size = info.end - info.start;
munmap(addr, size);
if (info.perms & map_info::READ) {
// Make sure readable pages are still readable
xmmap(addr, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
}
}
}
uintptr_t get_function_lib(uintptr_t addr, char *lib) {
uintptr_t base = 0;
parse_maps(getpid(), [=, &base](map_info &info) -> bool {
if (addr >= info.start && addr < info.end) {
if (lib)
strcpy(lib, info.path);
base = info.start;
return false;
}
return true;
});
return base;
}
uintptr_t get_remote_lib(int pid, const char *lib) {
uintptr_t base = 0;
parse_maps(pid, [=, &base](map_info &info) -> bool {
if (strcmp(info.path, lib) == 0 && (info.perms & map_info::EXEC)) {
base = info.start;
return false;
}
return true;
});
return base;
}