From 12dc1adf66ab56027075a4f8f5a803f1497722b9 Mon Sep 17 00:00:00 2001
From: Stephen Miller <millerste004@gmail.com>
Date: Thu, 27 Feb 2025 15:00:36 -0600
Subject: [PATCH] Revert "Remove SetPosixErrno"

This reverts commit bdfc0c246ce35cde015f3e48a284052ca4caf45e.
---
 src/core/libraries/kernel/file_system.cpp | 12 ++++++------
 src/core/libraries/kernel/kernel.cpp      | 12 ++++++++++++
 src/core/libraries/kernel/kernel.h        |  1 +
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/core/libraries/kernel/file_system.cpp b/src/core/libraries/kernel/file_system.cpp
index 75430e0d8..0a4877855 100644
--- a/src/core/libraries/kernel/file_system.cpp
+++ b/src/core/libraries/kernel/file_system.cpp
@@ -166,9 +166,9 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
         }
 
         if (e != 0) {
-            // IOFile code uses platform specific errnos. Use POSIX_EIO for now
+            // IOFile code uses platform specific errnos, they must be converted to POSIX errnos.
             h->DeleteHandle(handle);
-            *__Error() = POSIX_EIO;
+            SetPosixErrno(e);
             return -1;
         }
     }
@@ -375,8 +375,8 @@ s64 PS4_SYSV_ABI posix_lseek(s32 fd, s64 offset, s32 whence) {
 
     if (!file->f.Seek(offset, origin)) {
         if (errno != 0) {
-            // Seek failed in platform-specific code. Use POSIX_EIO for now.
-            *__Error() = POSIX_EIO;
+            // Seek failed in platform-specific code, errno needs to be converted.
+            SetPosixErrno(errno);
         } else {
             // Seek failed because offset is beyond the end of the file.
             *__Error() = POSIX_ENXIO;
@@ -386,8 +386,8 @@ s64 PS4_SYSV_ABI posix_lseek(s32 fd, s64 offset, s32 whence) {
 
     s64 result = file->f.Tell();
     if (result < 0) {
-        // Tell failed in platform-specific code. Use POSIX_EIO for now.
-        *__Error() = POSIX_EIO;
+        // Tell failed in platform-specific code, errno needs to be converted.
+        SetPosixErrno(errno);
         return -1;
     }
     return result;
diff --git a/src/core/libraries/kernel/kernel.cpp b/src/core/libraries/kernel/kernel.cpp
index d42f440c7..0ab8fac29 100644
--- a/src/core/libraries/kernel/kernel.cpp
+++ b/src/core/libraries/kernel/kernel.cpp
@@ -84,6 +84,18 @@ int ErrnoToSceKernelError(int error) {
     return error + ORBIS_KERNEL_ERROR_UNKNOWN;
 }
 
+void SetPosixErrno(int e) {
+    // Some error numbers are different between supported OSes
+    switch (e) {
+    case ENOENT:
+        g_posix_errno = POSIX_ENOENT;
+        break;
+    default:
+        UNREACHABLE_MSG("errno = {}", e);
+        g_posix_errno = e;
+    }
+}
+
 static uint64_t g_mspace_atomic_id_mask = 0;
 static uint64_t g_mstate_table[64] = {0};
 
diff --git a/src/core/libraries/kernel/kernel.h b/src/core/libraries/kernel/kernel.h
index 96ad4a876..8e7f475ad 100644
--- a/src/core/libraries/kernel/kernel.h
+++ b/src/core/libraries/kernel/kernel.h
@@ -16,6 +16,7 @@ namespace Libraries::Kernel {
 
 void ErrSceToPosix(int result);
 int ErrnoToSceKernelError(int e);
+void SetPosixErrno(int e);
 
 template <size_t N>
 struct StringLiteral {