From 195c97b3e2fecc62d78780bee0446d62c1f9b3ad Mon Sep 17 00:00:00 2001
From: "Jay Freeman (saurik)" <saurik@saurik.com>
Date: Thu, 2 Jul 2015 13:41:10 -0700
Subject: Use launch.h to verify cydo was launched by Cydia.

---
 cydo.cpp | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/cydo.cpp b/cydo.cpp
index 485d647..49e419a 100644
--- a/cydo.cpp
+++ b/cydo.cpp
@@ -1,7 +1,63 @@
+#include <cstdio>
+#include <cstdlib>
+
+#include <errno.h>
 #include <sysexits.h>
 #include <unistd.h>
 
+#include <launch.h>
+
+#include <Menes/Function.h>
+
+typedef Function<void, const char *, launch_data_t> LaunchDataIterator;
+
+void launch_data_dict_iterate(launch_data_t data, LaunchDataIterator code) {
+    launch_data_dict_iterate(data, [](launch_data_t value, const char *name, void *baton) {
+        (*static_cast<LaunchDataIterator *>(baton))(name, value);
+    }, &code);
+}
+
 int main(int argc, char *argv[]) {
+    auto request(launch_data_new_string(LAUNCH_KEY_GETJOBS));
+    auto response(launch_msg(request));
+    launch_data_free(request);
+
+    _assert(response != NULL);
+    _assert(launch_data_get_type(response) == LAUNCH_DATA_DICTIONARY);
+
+    int parent(getppid());
+
+    bool cydia(false);
+
+    launch_data_dict_iterate(response, [=, &cydia](const char *name, launch_data_t value) {
+        if (launch_data_get_type(response) != LAUNCH_DATA_DICTIONARY)
+            return;
+
+        auto integer(launch_data_dict_lookup(value, LAUNCH_JOBKEY_PID));
+        if (integer == NULL || launch_data_get_type(integer) != LAUNCH_DATA_INTEGER)
+            return;
+
+        auto pid(launch_data_get_integer(integer));
+        if (pid != parent)
+            return;
+
+        auto string(launch_data_dict_lookup(value, LAUNCH_JOBKEY_PROGRAM));
+        if (string == NULL || launch_data_get_type(string) != LAUNCH_DATA_STRING)
+            return;
+
+        auto program(launch_data_get_string(string));
+        if (program == NULL)
+            return;
+
+        if (strcmp(program, "/Applications/Cydia.app/Cydia") == 0)
+            cydia = true;
+    });
+
+    if (!cydia) {
+        fprintf(stderr, "thou shalt not pass\n");
+        return EX_NOPERM;
+    }
+
     setuid(0);
     setgid(0);
 
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