Magisk/jni/magiskhide/hide_daemon.c
2017-07-08 23:51:58 +08:00

130 lines
2.9 KiB
C

/* hide_daemon.c - MagiskHide daemon
*
* A dedicated process to join the target namespace,
* and hide all traces in that particular namespace
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include "magisk.h"
#include "utils.h"
#include "magiskhide.h"
static int pid;
static void lazy_unmount(const char* mountpoint) {
if (umount2(mountpoint, MNT_DETACH) != -1)
LOGI("hide_daemon: Unmounted (%s)\n", mountpoint);
else
LOGI("hide_daemon: Unmount Failed (%s)\n", mountpoint);
}
static void hide_daemon_err() {
LOGD("hide_daemon: error occured, stopping magiskhide services\n");
// Resume process if possible
kill(pid, SIGCONT);
int err = 1;
write(sv[1], &err, sizeof(err));
_exit(-1);
}
int hide_daemon() {
// Fork to a new process
hide_pid = fork();
switch(hide_pid) {
case -1:
PLOGE("fork");
return 1;
case 0:
break;
default:
return 0;
}
close(sv[0]);
// Set the process name
strcpy(argv0, "magiskhide_daemon");
LOGD("hide_daemon: listening for hide requests");
// When an error occurs, report its failure to main process
err_handler = hide_daemon_err;
char buffer[4096], cache_block[256], *line;
struct vector mount_list;
cache_block[0] = '\0';
while(1) {
xxread(sv[1], &pid, sizeof(pid));
// Termination called
if(pid == -1) {
LOGD("hide_daemon: received termination request\n");
_exit(0);
}
manage_selinux();
relink_sbin();
if (switch_mnt_ns(pid))
continue;
snprintf(buffer, sizeof(buffer), "/proc/%d/mounts", pid);
vec_init(&mount_list);
file_to_vector(buffer, &mount_list);
// Find the cache block name if not found yet
if (strlen(cache_block) == 0) {
vec_for_each(&mount_list, line) {
if (strstr(line, " /cache ")) {
sscanf(line, "%256s", cache_block);
break;
}
}
}
// First unmount dummy skeletons, /sbin links, cache mounts, and mirrors
vec_for_each(&mount_list, line) {
if (strstr(line, "tmpfs /system") || strstr(line, "tmpfs /vendor") || strstr(line, "tmpfs /sbin")
|| (strstr(line, cache_block) && (strstr(line, " /system") || strstr(line, " /vendor")))
|| strstr(line, MIRRDIR)) {
sscanf(line, "%*s %512s", buffer);
lazy_unmount(buffer);
}
free(line);
}
vec_destroy(&mount_list);
// Re-read mount infos
snprintf(buffer, sizeof(buffer), "/proc/%d/mounts", pid);
vec_init(&mount_list);
file_to_vector(buffer, &mount_list);
// Unmount any loop mounts and dummy mounts
vec_for_each(&mount_list, line) {
if (strstr(line, "/dev/block/loop") || strstr(line, DUMMDIR)) {
sscanf(line, "%*s %512s", buffer);
lazy_unmount(buffer);
}
free(line);
}
vec_destroy(&mount_list);
// All done, send resume signal
kill(pid, SIGCONT);
// Tell main process all is well
pid = 0;
xwrite(sv[1], &pid, sizeof(pid));
}
// Should never go here
}