From 45d88d496eeef3bbdd0b54a2b0c1618b81d533a4 Mon Sep 17 00:00:00 2001
From: Kiyoung Kim <kiyoungkim@google.com>
Date: Thu, 21 Sep 2023 16:03:41 +0900
Subject: [PATCH] Do not check with vendor vndk version

Current libcutils checks if memfd is supported with vendor VNDK version,
but this is no longer valid if VNDK is deprecated. As we can assume that
any vendor using this code is supported as long as it is treblelized,
simplify logic to check if memfd is valid to vendor only with
'ro.treble.enabled' property.

Bug: 290159430
Test: Cuttlefish with VNDK deprecated worked without error from
libcutils

Change-Id: I351f0798da99cb4827bc3e424b63a2eaee5c7461
---
 libcutils/ashmem-dev.cpp | 57 +++++-----------------------------------
 1 file changed, 6 insertions(+), 51 deletions(-)

diff --git a/libcutils/ashmem-dev.cpp b/libcutils/ashmem-dev.cpp
index 5e01da9b8..410dbfd5e 100644
--- a/libcutils/ashmem-dev.cpp
+++ b/libcutils/ashmem-dev.cpp
@@ -44,13 +44,6 @@
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 
-/*
- * The minimum vendor API level at and after which it is safe to use memfd.
- * This is to facilitate deprecation of ashmem.
- */
-#define MIN_MEMFD_VENDOR_API_LEVEL 29
-#define MIN_MEMFD_VENDOR_API_LEVEL_CHAR 'Q'
-
 /* ashmem identity */
 static dev_t __ashmem_rdev;
 /*
@@ -88,55 +81,17 @@ static bool pin_deprecation_warn = true; /* Log the pin deprecation warning only
 
 /* Determine if vendor processes would be ok with memfd in the system:
  *
- * If VNDK is using older libcutils, don't use memfd. This is so that the
- * same shared memory mechanism is used across binder transactions between
- * vendor partition processes and system partition processes.
+ * Previously this function checked if memfd is supported by checking if
+ * vendor VNDK version is greater than Q. As we can assume all treblelized
+ * device using this code is up to date enough to use memfd, memfd is allowed
+ * if the device is treblelized.
  */
 static bool check_vendor_memfd_allowed() {
-    std::string vndk_version = android::base::GetProperty("ro.vndk.version", "");
+    static bool is_treblelized = android::base::GetBoolProperty("ro.treble.enabled", false);
 
-    if (vndk_version == "") {
-        ALOGE("memfd: ro.vndk.version not defined or invalid (%s), this is mandated since P.\n",
-              vndk_version.c_str());
-        return false;
-    }
-
-    /* No issues if vendor is targetting current Dessert */
-    if (vndk_version == "current") {
-        return false;
-    }
-
-    /* Check if VNDK version is a number and act on it */
-    char* p;
-    long int vers = strtol(vndk_version.c_str(), &p, 10);
-    if (*p == 0) {
-        if (vers < MIN_MEMFD_VENDOR_API_LEVEL) {
-            ALOGI("memfd: device VNDK version (%s) is < Q so using ashmem.\n",
-                  vndk_version.c_str());
-            return false;
-        }
-
-        return true;
-    }
-
-    // Non-numeric should be a single ASCII character. Characters after the
-    // first are ignored.
-    if (tolower(vndk_version[0]) < 'a' || tolower(vndk_version[0]) > 'z') {
-        ALOGE("memfd: ro.vndk.version not defined or invalid (%s), this is mandated since P.\n",
-              vndk_version.c_str());
-        return false;
-    }
-
-    if (tolower(vndk_version[0]) < tolower(MIN_MEMFD_VENDOR_API_LEVEL_CHAR)) {
-        ALOGI("memfd: device is using VNDK version (%s) which is less than Q. Use ashmem only.\n",
-              vndk_version.c_str());
-        return false;
-    }
-
-    return true;
+    return is_treblelized;
 }
 
-
 /* Determine if memfd can be supported. This is just one-time hardwork
  * which will be cached by the caller.
  */