Magisk/native/jni/su/connect.cpp

#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>

#include <magisk.h>
#include <daemon.h>
#include <utils.h>

#include "su.h"

#define START_ACTIVITY \
"/system/bin/app_process", "/system/bin", "com.android.commands.am.Am", \
"start", "-n", nullptr, "--user", nullptr, "-f", "0x18000020", "-a"

// 0x18000020 = FLAG_ACTIVITY_NEW_TASK|FLAG_ACTIVITY_MULTIPLE_TASK|FLAG_INCLUDE_STOPPED_PACKAGES

static inline const char *get_command(const struct su_request *to) {
	if (to->command[0])
		return to->command;
	if (to->shell[0])
		return to->shell;
	return DEFAULT_SHELL;
}

static inline void get_user(char *user, struct su_info *info) {
	sprintf(user, "%d",
			info->cfg[SU_MULTIUSER_MODE] == MULTIUSER_MODE_USER
			? info->uid / 100000
			: 0);
}

static inline void get_uid(char *uid, struct su_info *info) {
	sprintf(uid, "%d",
			info->cfg[SU_MULTIUSER_MODE] == MULTIUSER_MODE_OWNER_MANAGED
			? info->uid % 100000
			: info->uid);
}

static void silent_run(const char **args, struct su_info *info) {
	char component[128];
	sprintf(component, "%s/a.m", info->str[SU_MANAGER].data());
	char user[8];
	get_user(user, info);

	/* Fill in dynamic arguments */
	args[5] = component;
	args[7] = user;

	exec_t exec {
		.pre_exec = []() -> void {
			int null = xopen("/dev/null", O_WRONLY | O_CLOEXEC);
			dup2(null, STDOUT_FILENO);
			dup2(null, STDERR_FILENO);
			setenv("CLASSPATH", "/system/framework/am.jar", 1);
		},
		.fork = fork_dont_care,
		.argv = args
	};
	exec_command(exec);
}

void app_log(struct su_context *ctx) {
	char fromUid[8];
	get_uid(fromUid, ctx->info);

	char toUid[8];
	sprintf(toUid, "%d", ctx->req.uid);

	char pid[8];
	sprintf(pid, "%d", ctx->pid);

	char policy[2];
	sprintf(policy, "%d", ctx->info->access.policy);

	const char *cmd[] = {
		START_ACTIVITY, "log",
		"--ei", "from.uid", fromUid,
		"--ei", "to.uid", toUid,
		"--ei", "pid", pid,
		"--ei", "policy", policy,
		"--es", "command", get_command(&ctx->req),
		"--ez", "notify", ctx->info->access.notify ? "true" : "false",
		nullptr
	};
	silent_run(cmd, ctx->info);
}

void app_notify(struct su_context *ctx) {
	char fromUid[8];
	get_uid(fromUid, ctx->info);

	char policy[2];
	sprintf(policy, "%d", ctx->info->access.policy);

	const char *cmd[] = {
		START_ACTIVITY, "notify",
		"--ei", "from.uid", fromUid,
		"--ei", "policy", policy,
		nullptr
	};
	silent_run(cmd, ctx->info);
}

void app_connect(const char *socket, struct su_info *info) {
	const char *cmd[] = {
		START_ACTIVITY, "request",
		"--es", "socket", socket,
		nullptr
	};
	silent_run(cmd, info);
}

void socket_send_request(int fd, struct su_info *info) {
	write_key_token(fd, "uid", info->uid);
	write_string_be(fd, "eof");
}