feat(libkernel): implement pthread_getname_np

Hades (PPSA03355) stops at load on main with "undefined symbol:
9HzfhdtESio", the NID of pthread_getname_np, which it calls on
pthread_self() with a 32-byte buffer. Measured on a PS5 (firmware 13.60)
through dlopen of libkernel: the function takes (thread, buffer), copies
the name and its terminator, returns an empty name for an unnamed
thread, ESRCH for a null or joined thread and EFAULT for a null buffer.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

core/libs/prx/libkernel/CMakeLists.txt

@@ -190,6 +190,16 @@ if(BUILD_TESTING)
         set_tests_properties(guest_thread_self PROPERTIES ENVIRONMENT_MODIFICATION
             "PATH=path_list_prepend:$<TARGET_FILE_DIR:libkernel>")
     endif()
+    add_test_executable(guest_pthread_getname_tests ${LIBS_INCLUDE_DIR}/tests/GuestPthreadGetname.cpp)
+    target_include_directories(guest_pthread_getname_tests PRIVATE ${LIBS_INCLUDE_DIR})
+    target_link_libraries(guest_pthread_getname_tests PRIVATE libkernel libc)
+    configure_windows_unwind(guest_pthread_getname_tests)
+    add_test(NAME guest_pthread_getname COMMAND guest_pthread_getname_tests)
+    set_tests_properties(guest_pthread_getname PROPERTIES TIMEOUT 20)
+    if(WIN32)
+        set_tests_properties(guest_pthread_getname PROPERTIES ENVIRONMENT_MODIFICATION
+            "PATH=path_list_prepend:$<TARGET_FILE_DIR:libkernel>")
+    endif()
     add_test_executable(guest_pthread_attr_tests ${LIBS_INCLUDE_DIR}/tests/GuestPthreadAttr.cpp)
     target_include_directories(guest_pthread_attr_tests PRIVATE ${LIBS_INCLUDE_DIR})
     target_link_libraries(guest_pthread_attr_tests PRIVATE libkernel libc)

core/libs/prx/libkernel/Pthread/Posix/Common.hpp

@@ -10,6 +10,8 @@ extern "C" int APS5_VABI clock_gettime_nid_postfix(int clockId, KernelTimespec*
 
 namespace PosixThread {
 
+constexpr int GUEST_ESRCH = 3;
+constexpr int GUEST_EFAULT = 14;
 constexpr int GUEST_EINVAL = 22;
 constexpr int GUEST_ETIMEDOUT = 60;
 

core/libs/prx/libkernel/Pthread/Posix/Thread.cpp

@@ -15,6 +15,7 @@ int APS5_VABI scePthreadDetach(Pthread thread);
 void APS5_VABI scePthreadExit(void* retval);
 int APS5_VABI scePthreadJoin(Pthread thread, void** retval);
 int APS5_VABI scePthreadRename(Pthread thread, const char* name);
+int APS5_VABI scePthreadGetname(Pthread thread, char* name);
 Pthread APS5_VABI scePthreadSelf();
 int APS5_VABI scePthreadSetcancelstate(int state, int* old_state);
 void APS5_VABI scePthreadTestcancel();
@@ -68,6 +69,12 @@ int APS5_VABI pthread_rename_np_nid_postfix(Pthread thread, const char* name) {
     return PosixThread::ToErrno(scePthreadRename(thread, name));
 }
 
+int APS5_VABI pthread_getname_np_nid_postfix(Pthread thread, char* name) {
+    if (!thread) return PosixThread::GUEST_ESRCH;
+    if (!name) return PosixThread::GUEST_EFAULT;
+    return PosixThread::ToErrno(scePthreadGetname(thread, name));
+}
+
 Pthread APS5_VABI pthread_self_nid_postfix(void) {
     return scePthreadSelf();
 }

core/libs/tests/GuestPthreadGetname.cpp

@@ -0,0 +1,51 @@
+#include "SceTypes.hpp"
+#include <array>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+
+extern "C" {
+Pthread APS5_VABI pthread_self_nid_postfix(void);
+int APS5_VABI pthread_rename_np_nid_postfix(Pthread thread, const char* name);
+int APS5_VABI pthread_getname_np_nid_postfix(Pthread thread, char* name);
+int APS5_VABI scePthreadCreate(Pthread* thread, const PthreadAttr* attr, PthreadEntry entry, void* arg, const char* name);
+int APS5_VABI scePthreadJoin(Pthread thread, void** retval);
+}
+
+static constexpr int GUEST_ESRCH = 3;
+static constexpr int GUEST_EFAULT = 14;
+
+static void Require(bool value) { if (!value) std::abort(); }
+
+static std::array<unsigned char, 64> Read(Pthread thread, int expected) {
+    std::array<unsigned char, 64> buffer{};
+    buffer.fill(0xAA);
+    Require(pthread_getname_np_nid_postfix(thread, reinterpret_cast<char*>(buffer.data())) == expected);
+    return buffer;
+}
+
+static void RequireName(Pthread thread, const std::string& name) {
+    const auto buffer = Read(thread, 0);
+    Require(std::memcmp(buffer.data(), name.c_str(), name.size() + 1) == 0);
+    for (std::size_t index = name.size() + 1; index < buffer.size(); ++index) Require(buffer[index] == 0xAA);
+}
+
+static void* APS5_VABI Unnamed(void*) {
+    RequireName(pthread_self_nid_postfix(), "");
+    return nullptr;
+}
+
+int main() {
+    const Pthread self = pthread_self_nid_postfix();
+    for (const char* name : {"", "A", "AnyPS5Probe", "0123456789012345678901234567890"}) {
+        Require(pthread_rename_np_nid_postfix(self, name) == 0);
+        RequireName(self, name);
+    }
+    Pthread worker = nullptr;
+    Require(scePthreadCreate(&worker, nullptr, Unnamed, nullptr, nullptr) == 0);
+    Require(scePthreadJoin(worker, nullptr) == 0);
+
+    const auto untouched = Read(nullptr, GUEST_ESRCH);
+    for (unsigned char byte : untouched) Require(byte == 0xAA);
+    Require(pthread_getname_np_nid_postfix(self, nullptr) == GUEST_EFAULT);
+}

docs/dev/TechnicalDebt.md

@@ -135,6 +135,7 @@ Throughout the project, every function at every stage either **does exactly what
 - [std_execute_once](../../core/libs/prx/libc/Export.cpp) (libc) - assumed to be the plain-named twin of `std::_Execute_once` (`_ZSt13_Execute_onceRSt9once_flagPFiPvS1_PS1_ES1_`, the callee of Dinkumware `call_once`): it delegates there and gets the [thread.once.callonce] semantics already verified for that symbol (one invocation per flag, concurrent callers block until it completes, and a failing or throwing invocation leaves the flag unready so the next caller runs it). The name equivalence is not confirmed on a title, and the callback convention (called with (null, arg, null), non-zero return meaning success) is the twin's, unverified for this symbol
 - [__progname](../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - unknown data export
 - [pthread_barrierattr_setpshared](../../core/libs/prx/libkernel/Pthread/Posix/Barrier.cpp) (libkernel) - PTHREAD_PROCESS_SHARED is accepted on the assumption that the console follows FreeBSD 11.0 libthr, which accepts it (9.0 rejects it with EINVAL); unverified on hardware. Guest code runs in one process, so a shared barrier behaves as a private one
+- [pthread_getname_np](../../core/libs/prx/libkernel/Pthread/Posix/Thread.cpp) (libkernel) - a thread that has already been joined returns `ESRCH` (3) on a PS5 (firmware 13.60), but its object is freed after the join here, so the pointer cannot be told apart from a live thread and its name is read as for a live one
 - [sceSslClose](../../core/libs/prx/libSceSsl/Export.cpp) (libSceSsl) - unknown signature
 - [sceSslGetSerialNumber](../../core/libs/prx/libSceSsl/Export.cpp) (libSceSsl) - unknown signature
 - [X+4jdIS75P0](../../core/libs/prx/libSceAudioIn/Export.cpp) (libSceAudioIn) - unknown name, signature