From df3aa1a9db8f977b52962322c95fd93d52d37f04 Mon Sep 17 00:00:00 2001
From: XairRrR <dev910382@gmail.com>
Date: Thu, 8 Oct 2026 14:58:06 +0200
Subject: [PATCH] fix(libkernel): raise the open file soft limit on Linux

Each direct memory backing keeps a memfd open, so a title such as
Dreaming Sarah (PPSA02929) holds about 1100 descriptors at startup.
With the systemd default soft limit of 1024, later opens fail with
EMFILE: memfd_create throws "create direct memory backing: Too many
open files", or the title's fopen returns NULL and it faults in fread.

libkernel now raises the RLIMIT_NOFILE soft limit to the hard limit
when it is loaded, before the title creates any descriptor, and throws
if the limit cannot be read or raised.
---
 core/libs/prx/libkernel/CMakeLists.txt        |  1 +
 .../prx/libkernel/File/src/OpenFileLimit.cpp  | 21 +++++++++++++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 core/libs/prx/libkernel/File/src/OpenFileLimit.cpp

diff --git a/core/libs/prx/libkernel/CMakeLists.txt b/core/libs/prx/libkernel/CMakeLists.txt
index 2520ab477..37c28d6f8 100644
--- a/core/libs/prx/libkernel/CMakeLists.txt
+++ b/core/libs/prx/libkernel/CMakeLists.txt
@@ -6,6 +6,7 @@ add_library(libkernel SHARED EXCLUDE_FROM_ALL
         ${CMAKE_CURRENT_SOURCE_DIR}/File/src/DirectoryDescriptor.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/File/src/NativeStat.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/File/src/Open.cpp
+        ${CMAKE_CURRENT_SOURCE_DIR}/File/src/OpenFileLimit.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/File/src/Stdio.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/Semaphore/src/Semaphore.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/SyncOnAddress/src/SyncOnAddress.cpp
diff --git a/core/libs/prx/libkernel/File/src/OpenFileLimit.cpp b/core/libs/prx/libkernel/File/src/OpenFileLimit.cpp
new file mode 100644
index 000000000..6d698a585
--- /dev/null
+++ b/core/libs/prx/libkernel/File/src/OpenFileLimit.cpp
@@ -0,0 +1,21 @@
+#if defined(__linux__)
+
+#include <cerrno>
+#include <system_error>
+#include <sys/resource.h>
+
+namespace {
+
+struct OpenFileLimit {
+    OpenFileLimit() {
+        rlimit limit{};
+        if (getrlimit(RLIMIT_NOFILE, &limit) != 0) throw std::system_error(errno, std::generic_category(), "read open file limit");
+        if (limit.rlim_cur >= limit.rlim_max) return;
+        limit.rlim_cur = limit.rlim_max;
+        if (setrlimit(RLIMIT_NOFILE, &limit) != 0) throw std::system_error(errno, std::generic_category(), "raise open file limit");
+    }
+} openFileLimit;
+
+}
+
+#endif