Magisk/native/jni/core/magisk.cpp
topjohnwu 25c557248c Use ContentProvider call method for communication
Previously, we use either BroadcastReceivers or Activities to receive
messages from our native daemon, but both have their own downsides.
Some OEMs blocks broadcasts if the app is not running in the background,
regardless of who the caller is. Activities on the other hand, despite
working 100% of the time, will steal the focus of the current foreground
app, even though we are just doing some logging and showing a toast.
In addition, since stubs for hiding Magisk Manager is introduced, our
only communication method is left with the broadcast option, as
only broadcasting allows targeting a specific package name, not a
component name (which will be obfuscated in the case of stubs).

To make sure root requests will work on all devices, Magisk had to do
some experiments every boot to test whether broadcast is deliverable or
not. This makes the whole thing even more complicated then ever.

So lets take a look at another kind of component in Android apps:
ContentProviders. It is a vital part of Android's ecosystem, and as far
as I know no OEMs will block requests to ContentProviders (or else
tons of functionality will break catastrophically). Starting at API 11,
the system supports calling a specific method in ContentProviders,
optionally sending extra data along with the method call. This is
perfect for the native daemon to start a communication with Magisk
Manager. Another cool thing is that we no longer need to know the
component name of the reciever, as ContentProviders identify themselves
with an "authority" name, which in Magisk Manager's case is tied to the
package name. We already have a mechanism to keep track of our current
manager package name, so this works out of the box.

So yay! No more flaky broadcast tests, no more stupid OEMs blocking
broadcasts for some bizzare reasons. This method should in theory
work on almost all devices and situations.
2019-11-04 14:32:28 -05:00

127 lines
3.3 KiB
C++

#include <sys/mount.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <libgen.h>
#include <string.h>
#include <utils.h>
#include <magisk.h>
#include <daemon.h>
#include <selinux.h>
#include <flags.h>
using namespace std::literals;
[[noreturn]] static void usage() {
fprintf(stderr,
FULL_VER(Magisk) R"EOF( multi-call binary
Usage: magisk [applet [arguments]...]
or: magisk [options]...
Options:
-c print current binary version
-v print running daemon version
-V print running daemon version code
--list list all available applets
--daemon manually start magisk daemon
--remove-modules remove all modules and reboot
--[init trigger] start service for init trigger
Advanced Options (Internal APIs):
--unlock-blocks set BLKROSET flag to OFF for all block devices
--restorecon restore selinux context on Magisk files
--clone-attr SRC DEST clone permission, owner, and selinux context
--clone SRC DEST clone SRC to DEST
--sqlite SQL exec SQL commands to Magisk database
Supported init triggers:
post-fs-data, service, boot-complete
Supported applets:
)EOF");
for (int i = 0; applet_names[i]; ++i)
fprintf(stderr, i ? ", %s" : " %s", applet_names[i]);
fprintf(stderr, "\n\n");
exit(1);
}
int magisk_main(int argc, char *argv[]) {
if (argc < 2)
usage();
if (argv[1] == "-c"sv) {
printf(MAGISK_VERSION ":MAGISK (" str(MAGISK_VER_CODE) ")\n");
return 0;
} else if (argv[1] == "-v"sv) {
int fd = connect_daemon();
write_int(fd, CHECK_VERSION);
char *v = read_string(fd);
printf("%s\n", v);
free(v);
return 0;
} else if (argv[1] == "-V"sv) {
int fd = connect_daemon();
write_int(fd, CHECK_VERSION_CODE);
printf("%d\n", read_int(fd));
return 0;
} else if (argv[1] == "--list"sv) {
for (int i = 0; applet_names[i]; ++i)
printf("%s\n", applet_names[i]);
return 0;
} else if (argv[1] == "--unlock-blocks"sv) {
unlock_blocks();
return 0;
} else if (argv[1] == "--restorecon"sv) {
restore_rootcon();
restorecon();
return 0;
} else if (argc >= 4 && argv[1] == "--clone-attr"sv) {;
clone_attr(argv[2], argv[3]);
return 0;
} else if (argc >= 4 && argv[1] == "--clone"sv) {
cp_afc(argv[2], argv[3]);
return 0;
} else if (argv[1] == "--daemon"sv) {
int fd = connect_daemon(true);
write_int(fd, DO_NOTHING);
return 0;
} else if (argv[1] == "--post-fs-data"sv) {
int fd = connect_daemon(true);
write_int(fd, POST_FS_DATA);
return read_int(fd);
} else if (argv[1] == "--service"sv) {
int fd = connect_daemon(true);
write_int(fd, LATE_START);
return read_int(fd);
} else if (argv[1] == "--boot-complete"sv) {
int fd = connect_daemon(true);
write_int(fd, BOOT_COMPLETE);
return read_int(fd);
} else if (argc >= 3 && argv[1] == "--sqlite"sv) {
int fd = connect_daemon();
write_int(fd, SQLITE_CMD);
write_string(fd, argv[2]);
for (;;) {
char *res = read_string(fd);
if (res[0] == '\0') {
return 0;
}
printf("%s\n", res);
free(res);
}
} else if (argv[1] == "--remove-modules"sv) {
int fd = connect_daemon();
write_int(fd, REMOVE_MODULES);
return read_int(fd);
}
#if 0
/* Entry point for testing stuffs */
else if (argv[1] == "--test"sv) {
return 0;
}
#endif
usage();
}