init-sigstop-based ptrace zygisk

loader/src/ptracer/monitor.cpp

@@ -0,0 +1,37 @@
+#include <sys/system_properties.h>
+#include <unistd.h>
+
+#include "main.hpp"
+#include "utils.hpp"
+
+void prop_monitor_main() {
+    LOGI("prop monitor started");
+    // if service is not running, pid = ""
+    auto name = "init.svc_debug_pid." LP_SELECT("zygote_secondary", "zygote"); // argv[1];
+    LOGI("start monitoring %s", name);
+    auto prop = __system_property_find(name);
+    if (prop == nullptr) {
+        __system_property_set(name, "");
+        prop = __system_property_find(name);
+        if (prop == nullptr) {
+            LOGE("failed to create prop");
+            exit(1);
+        }
+    }
+    char val[PROP_VALUE_MAX];
+    uint32_t new_serial = 0;
+    while (true) {
+        __system_property_wait(prop, new_serial, &new_serial, nullptr);
+        __system_property_get(name, val);
+        LOGD("%s(%u): %s\n", name, new_serial, val);
+        auto pid = strtol(val, nullptr, 0);
+        if (pid != 0) {
+            LOGD("start ptrace %ld", pid);
+            if (fork_dont_care() == 0) {
+                execl("/proc/self/exe", "zygisk-ptracer", "trace-zygote", val, nullptr);
+                PLOGE("failed to exec");
+                exit(1);
+            }
+        }
+    }
+}