RPCS3: realpath from the platform layer; SDK 8160289

A title's realpath answers EPERM, even for /app0, so RPCS3's package installer
could not normalise its installation path (std::filesystem's canonical paths
are built on realpath). The title and the cores now bind realpath to
ps5_realpath (SDK 8160289).

docs/RPCS3_PORT.md

@@ -425,7 +425,7 @@ unloaded, so the next load finds its addresses free.
 handler it replaced (the title's crash reporter), and the title's handlers
 return when the core is unloaded.
 
-**Platform gaps closed in the SDK (a9fbb6a).** Each is aliased in
+**Platform gaps closed in the SDK (8160289).** Each is aliased in
 `tools/core-imports.py`.
 
 - No export at all: `accept4`, `getpagesizes`, `in6addr_any`.
@@ -437,6 +437,12 @@ return when the core is unloaded.
 - Answered differently on the console: `pthread_getaffinity_np` and
   `pthread_setaffinity_np` (the 64-bit mask), `sysconf` (13 CPUs, not 16),
   `pthread_exit` (a thread's `thread_local` destructors first).
+- Refused: `realpath` answers EPERM, even for `/app0`, so libc++'s
+  `std::filesystem::canonical` and `weakly_canonical` came back empty and the
+  package installer could not normalise its path. `ps5_realpath` makes the path
+  absolute, resolves `.` and `..` by name and checks each component with
+  `stat`; it keeps a symbolic link's name. The title links it too
+  (`--wrap=realpath`).
 - Memory: committed ranges (`ps5_vrange_commit`), exact reservations, zeroing
   of reused direct memory, and placement up to 1 TiB.
 

src/platform_wraps.c

@@ -45,6 +45,13 @@ DIR *__wrap_fdopendir(int fd)
     return ps5_fdopendir(fd);
 }
 
+/* A title's realpath is refused (EPERM); libc++'s std::filesystem canonical
+ * paths are built on it. */
+char *__wrap_realpath(const char *path, char *resolved)
+{
+    return ps5_realpath(path, resolved);
+}
+
 DIR *__wrap_opendir(const char *path)
 {
     return ps5_opendir(path);

tests/test_core_imports.py

@@ -29,16 +29,20 @@ class CoreImports(unittest.TestCase):
         self.assertIn('asm("ps5_rewinddir")', generated)
         self.assertIn('asm("ps5_opendir")', generated)
 
-    def test_aligned_new_and_getcwd_bind_to_the_title(self):
+    def test_aligned_new_getcwd_and_realpath_bind_to_the_title(self):
         # Over-aligned operator new comes from direct memory, as plain new does,
-        # and getcwd from the platform layer (libc's faults for a title).
+        # and getcwd and realpath from the platform layer (libc's fault or are
+        # refused for a title).
         generated = imports.generate({'_ZnwmSt11align_val_t': ('FUNC', False),
                                       '_ZnamSt11align_val_t': ('FUNC', False),
                                       '_ZnwmSt11align_val_tRKSt9nothrow_t': ('FUNC', False),
-                                      'getcwd': ('FUNC', False)})
+                                      'getcwd': ('FUNC', False),
+                                      'realpath': ('FUNC', False)})
         self.assertIn('asm("ps5_core_new_aligned")', generated)
         self.assertIn('asm("ps5_core_new_aligned_nothrow")', generated)
         self.assertIn('asm("ps5_getcwd")', generated)
+        self.assertIn('asm("ps5_realpath")', generated)
+        self.assertNotIn('asm("realpath")', generated)
         self.assertNotIn('asm("_ZnwmSt11align_val_t")', generated)
 
     def test_weak_only_when_every_core_imports_weakly(self):

tools/build-title.sh

@@ -274,6 +274,9 @@ PY
 # payload SDK fork), and src/platform_wraps.c binds these links to it. A core's
 # own imports of the same calls are bound to it by tools/core-imports.py.
 directory_wrap_flags="--wrap=opendir --wrap=readdir --wrap=closedir --wrap=fdopendir --wrap=openat --wrap=unlinkat --wrap=fchmodat"
+# realpath is refused to a title, so std::filesystem::canonical and
+# weakly_canonical (RPCS3's package installer) came back empty.
+directory_wrap_flags+=" --wrap=realpath"
 # Folders the title or a core creates are 0777 and files at least 0666, so FTP,
 # which runs as another user, can reach them (src/permissions_ps5.cpp).
 directory_wrap_flags+=" --wrap=mkdir --wrap=open --wrap=fopen"

tools/core-imports.py

@@ -98,7 +98,9 @@ def generate(imports):
                # src/core_loader_ps5.cpp: the console's, plus dlopen(NULL), the
                # process handle LLVM's JIT asks for.
                'dlopen': 'ps5_cores_dlopen', 'dlsym': 'ps5_cores_dlsym',
-               'dlclose': 'ps5_cores_dlclose', 'dlerror': 'ps5_cores_dlerror'}
+               'dlclose': 'ps5_cores_dlclose', 'dlerror': 'ps5_cores_dlerror',
+               # Refused to a title (EPERM), even for /app0.
+               'realpath': 'ps5_realpath'}
     for index, (name, (kind, weak)) in enumerate(sorted(imports.items())):
         target = aliases.get(name, name)
         declaration = f'void core_import_{index}()' if kind == 'FUNC' else f'char core_import_{index}[]'

tools/setup-native-dependencies.sh

@@ -23,7 +23,7 @@ zlib_stamp="$zlib_root/.source-version"
 # there). The pinned revision is exported with git archive, so a build never
 # depends on the fork's working tree, and the SDK directory records it.
 sdk_fork="${PS5_PAYLOAD_SDK_FORK:-$root/../PS5_PayloadSDK}"
-sdk_revision=a9fbb6a9c9c67567ef5561c74075ce5e2ee9b21b
+sdk_revision=8160289a132263853f4c7cff542d9d6edc0c7c12
 zlib_url="https://zlib.net/fossils/zlib-$zlib_version.tar.gz"
 zlib_hash="bb329a0a2cd0274d05519d61c667c062e06990d72e125ee2dfa8de64f0119d16"
 skip_sdk=false