From 3cc56bf84ce03dc049baa200a10a449ca84afe2d Mon Sep 17 00:00:00 2001
From: Stephen Miller <56742918+StevenMiller123@users.noreply.github.com>
Date: Wed, 25 Mar 2026 16:43:30 -0500
Subject: [PATCH] More verbose errors for file opening failures (#4173)

* Verbose errors for file opening failures

These can be pretty helpful, and games don't usually spam them outside loading screens.

* oops
---
 src/core/libraries/kernel/file_system.cpp          | 14 +++++++++++++-
 .../libraries/libc_internal/libc_internal_io.cpp   |  6 +++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/core/libraries/kernel/file_system.cpp b/src/core/libraries/kernel/file_system.cpp
index 184343801..085e18b9f 100644
--- a/src/core/libraries/kernel/file_system.cpp
+++ b/src/core/libraries/kernel/file_system.cpp
@@ -87,11 +87,13 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
     if (!read && !write && !rdwr) {
         // Start by checking for invalid flags.
         *__Error() = POSIX_EINVAL;
+        LOG_ERROR(Kernel_Fs, "Opening path {} failed, invalid flags {:#x}", raw_path, flags);
         return -1;
     }
 
     if (strlen(raw_path) > 255) {
         *__Error() = POSIX_ENAMETOOLONG;
+        LOG_ERROR(Kernel_Fs, "Opening path {} failed, path is too long", raw_path);
         return -1;
     }
 
@@ -137,6 +139,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
             // Error if file exists
             h->DeleteHandle(handle);
             *__Error() = POSIX_EEXIST;
+            LOG_ERROR(Kernel_Fs, "Creating {} failed, file already exists", raw_path);
             return -1;
         }
 
@@ -145,6 +148,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
                 // Can't create files in a read only directory
                 h->DeleteHandle(handle);
                 *__Error() = POSIX_EROFS;
+                LOG_ERROR(Kernel_Fs, "Creating {} failed, path is read-only", raw_path);
                 return -1;
             }
             // Create a file if it doesn't exist
@@ -154,6 +158,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
         // If we're not creating a file, and it doesn't exist, return ENOENT
         h->DeleteHandle(handle);
         *__Error() = POSIX_ENOENT;
+        LOG_ERROR(Kernel_Fs, "Opening path {} failed, file does not exist", raw_path);
         return -1;
     }
 
@@ -169,6 +174,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
             // This will trigger when create & directory is specified, this is expected.
             h->DeleteHandle(handle);
             *__Error() = POSIX_ENOTDIR;
+            LOG_ERROR(Kernel_Fs, "Opening directory {} failed, file is not a directory", raw_path);
             return -1;
         }
 
@@ -176,6 +182,8 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
             // Cannot open directories with any type of write access
             h->DeleteHandle(handle);
             *__Error() = POSIX_EISDIR;
+            LOG_ERROR(Kernel_Fs, "Opening directory {} failed, cannot open directories for writing",
+                      raw_path);
             return -1;
         }
 
@@ -183,6 +191,8 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
             // Cannot open directories with truncate
             h->DeleteHandle(handle);
             *__Error() = POSIX_EISDIR;
+            LOG_ERROR(Kernel_Fs, "Opening directory {} failed, cannot truncate directories",
+                      raw_path);
             return -1;
         }
 
@@ -201,6 +211,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
             // Can't open files with truncate flag in a read only directory
             h->DeleteHandle(handle);
             *__Error() = POSIX_EROFS;
+            LOG_ERROR(Kernel_Fs, "Truncating {} failed, path is read-only", raw_path);
             return -1;
         } else if (truncate) {
             // Open the file as read-write so we can truncate regardless of flags.
@@ -219,6 +230,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
             // Can't open files with write/read-write access in a read only directory
             h->DeleteHandle(handle);
             *__Error() = POSIX_EROFS;
+            LOG_ERROR(Kernel_Fs, "Opening {} for writing failed, path is read-only", raw_path);
             return -1;
         } else if (write) {
             if (append) {
@@ -244,6 +256,7 @@ s32 PS4_SYSV_ABI open(const char* raw_path, s32 flags, u16 mode) {
         // Open failed in platform-specific code, errno needs to be converted.
         h->DeleteHandle(handle);
         SetPosixErrno(e);
+        LOG_ERROR(Kernel_Fs, "Opening {} failed, error = {}", raw_path, *__Error());
         return -1;
     }
 
@@ -258,7 +271,6 @@ s32 PS4_SYSV_ABI posix_open(const char* filename, s32 flags, u16 mode) {
 s32 PS4_SYSV_ABI sceKernelOpen(const char* path, s32 flags, /* SceKernelMode*/ u16 mode) {
     s32 result = open(path, flags, mode);
     if (result < 0) {
-        LOG_ERROR(Kernel_Fs, "error = {}", *__Error());
         return ErrnoToSceKernelError(*__Error());
     }
     return result;
diff --git a/src/core/libraries/libc_internal/libc_internal_io.cpp b/src/core/libraries/libc_internal/libc_internal_io.cpp
index 504ba5b48..0bb23eb78 100644
--- a/src/core/libraries/libc_internal/libc_internal_io.cpp
+++ b/src/core/libraries/libc_internal/libc_internal_io.cpp
@@ -199,7 +199,11 @@ OrbisFILE* PS4_SYSV_ABI internal_fopen(const char* path, const char* mode) {
     std::scoped_lock lk{g_file_mtx};
     LOG_INFO(Lib_LibcInternal, "called, path {}, mode {}", path, mode);
     OrbisFILE* file = internal__Fofind();
-    return internal__Foprep(path, mode, file, -1, 0, 0);
+    OrbisFILE* ret_file = internal__Foprep(path, mode, file, -1, 0, 0);
+    if (ret_file == nullptr) {
+        LOG_ERROR(Lib_LibcInternal, "failed to open file {}", path);
+    }
+    return ret_file;
 }
 
 s32 PS4_SYSV_ABI internal_fflush(OrbisFILE* file) {