feat(libkernel): implement setpriority

core/libs/prx/libkernel/System/src/Process.cpp

@@ -126,7 +126,9 @@ constexpr int guestRlimitFsize = 1;
 constexpr int guestPriorityProcess = 0;
 constexpr int guestPriorityGroup = 1;
 constexpr int guestPriorityUser = 2;
-constexpr int guestNice = 0;
+std::atomic<int> guestNice{0};
+constexpr int guestNiceMin = -20;
+constexpr int guestNiceMax = 20;
 constexpr int guestRlimitData = 2;
 constexpr int guestRlimitCore = 4;
 constexpr int guestRlimitSbsize = 9;
@@ -564,7 +566,23 @@ int APS5_VABI getpriority_nid_postfix(int which, int who) {
         *__error_nid_postfix() = guestNoProcess;
         return -1;
     }
-    return guestNice;
+    return guestNice.load(std::memory_order_relaxed);
+}
+
+int APS5_VABI setpriority_nid_postfix(int which, int who, int niceval) {
+    if (which != guestPriorityProcess && which != guestPriorityGroup && which != guestPriorityUser) {
+        *__error_nid_postfix() = guestInvalid;
+        return -1;
+    }
+    const bool found = which == guestPriorityUser ? (who == 0 ? getuid_nid_postfix() : who) == getuid_nid_postfix()
+                                                  : who == 0 || who == getpid_nid_postfix();
+    if (!found) {
+        *__error_nid_postfix() = guestNoProcess;
+        return -1;
+    }
+    const int clamped = niceval < guestNiceMin ? guestNiceMin : (niceval > guestNiceMax ? guestNiceMax : niceval);
+    guestNice.store(clamped, std::memory_order_relaxed);
+    return 0;
 }
 
 int APS5_VABI sceKernelIsTrinityMode(void) {

core/libs/tests/GuestSchedPriority.cpp

@@ -6,6 +6,7 @@ extern "C" {
 int APS5_VABI sched_get_priority_max_nid_postfix(int policy);
 int APS5_VABI sched_get_priority_min_nid_postfix(int policy);
 int APS5_VABI getpriority_nid_postfix(int which, int who);
+int APS5_VABI setpriority_nid_postfix(int which, int who, int niceval);
 int APS5_VABI getpid_nid_postfix(void);
 int* APS5_VABI __error_nid_postfix();
 }
@@ -27,6 +28,14 @@ static void RequireError(int which, int who, int error) {
     *__error_nid_postfix() = 0;
     Require(getpriority_nid_postfix(which, who) == -1 && *__error_nid_postfix() == error);
 }
+static void RequireSet(int which, int who, int nice) {
+    *__error_nid_postfix() = 13;
+    Require(setpriority_nid_postfix(which, who, nice) == 0 && *__error_nid_postfix() == 13);
+}
+static void RequireSetError(int which, int who, int nice, int error) {
+    *__error_nid_postfix() = 0;
+    Require(setpriority_nid_postfix(which, who, nice) == -1 && *__error_nid_postfix() == error);
+}
 int main() {
     Require(Rejects(-1) && Rejects(2) && Rejects(5));
     for (int policy : {1, 3}) {
@@ -46,4 +55,19 @@ int main() {
     RequireError(PrioUser, 1000, 3);
     RequireError(3, 0, 22);
     RequireError(-1, self, 22);
+    RequireSet(PrioProcess, 0, 0);
+    RequireSet(PrioProcess, self, 5);
+    RequireSet(PrioProcess, self, -20);
+    RequireSet(PrioGroup, 0, 20);
+    RequireSet(PrioUser, 0, -1);
+    RequireSetError(PrioProcess, self + 1, 0, 3);
+    RequireSetError(PrioProcess, -1, 0, 3);
+    RequireSetError(PrioGroup, self + 1, 0, 3);
+    RequireSetError(PrioUser, 1000, 0, 3);
+    RequireSetError(3, 0, 0, 22);
+    RequireSetError(-1, self, 0, 22);
+    Require(setpriority_nid_postfix(PrioProcess, 0, 10) == 0 && getpriority_nid_postfix(PrioProcess, 0) == 10);
+    Require(setpriority_nid_postfix(PrioProcess, 0, 99) == 0 && getpriority_nid_postfix(PrioProcess, 0) == 20);
+    Require(setpriority_nid_postfix(PrioProcess, 0, -99) == 0 && getpriority_nid_postfix(PrioProcess, 0) == -20);
+    Require(setpriority_nid_postfix(PrioProcess, 0, 0) == 0 && getpriority_nid_postfix(PrioProcess, 0) == 0);
 }

docs/dev/debt/libkernel.md

@@ -176,4 +176,4 @@
 - [sceKernelGetPageTableStats](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) - reports 2048 page-table entries on each side (a 4 GiB pool of 2 MiB entries, the constants of [KytyPS5](https://github.com/KytyPS5/KytyPS5/blob/main/src/kernel/memory.cpp)) and all of them available: no entries are counted as used, so a title never sees page-table pressure. KytyPS5 counts the 2 MiB entries of the committed CPU- or GPU-accessible ranges as used, which this port does not do. The four `int*` arguments follow OpenOrbis' `libkernel.h`, the Orbital type database and SharpProspero; a null pointer returns `SCE_KERNEL_ERROR_EFAULT` as in KytyPS5. None of the values is measured on a console. PPSA30601 (Resonance) calls it during start-up
 - [clock_settime](../../../core/libs/prx/libkernel/Time/Time.cpp) (libkernel) validates like FreeBSD 11.4's [`kern_clock_settime`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_time.c#L396-L412) for a root caller: `EFAULT` for a null time, `EINVAL` for any clock but `CLOCK_REALTIME`, a negative second count or a nanosecond count outside 0 to 999999999. A valid `CLOCK_REALTIME` request throws, naming the requested time, since the host clock is never set and no guest clock offset is kept. FreeBSD checks `PRIV_CLOCK_SETTIME` first, which a jailed process fails with `EPERM`; whether a title holds it on the console is unverified. PS5MC (PPSA99420) imports it; no call site is known
 - [chflags](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) follows FreeBSD 11.4's [`kern_chflagsat`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/vfs_syscalls.c#L2366-L2383) and UFS's [`ufs_setattr`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/ufs/ufs/ufs_vnops.c#L509-L556) for a root caller: the path lookup reports `EFAULT`, `ENOENT` and `ENOTDIR`, a flag outside the 17 UFS stores (`VNOVAL` included) `EOPNOTSUPP`, and `SF_SNAPSHOT` `EPERM`. Neither host keeps BSD file flags, so every file is taken to have none (`stat` reports `st_flags` 0): flags 0 succeed without touching the file, and any other flag throws, naming the flags. `UF_READONLY`, `UF_HIDDEN`, `UF_SYSTEM` and `UF_ARCHIVE` are FreeBSD's names for the Windows attributes but are not mapped to them: UFS stores them without enforcing them, `FILE_ATTRIBUTE_READONLY` already carries the owner write bit of `chmod` on Windows, and Linux has no equivalent a process can set without `CAP_LINUX_IMMUTABLE`. The console's filesystem types, `EROFS` on read-only mounts and the change-time update are not modelled
-- [getpriority](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) follows FreeBSD 11.4's [`sys_getpriority`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_resource.c#L93-L165) for the only guest process, which is taken to run at nice 0: `PRIO_PROCESS` and `PRIO_PGRP` with 0 or its own pid (the guest is taken to lead its own process group, see `kill`) and `PRIO_USER` with 0 or its user id 0 return 0, any other id fails with `ESRCH` and any other `which` with `EINVAL`. As in FreeBSD's libc, where `getpriority` is the bare system call, errno is left unchanged on success. The nice value of a title process on the console is unverified, and the host nice of the process or of the threads `APS5_THREAD_PRIORITY=high` raises is not reported
+- [getpriority](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) follows FreeBSD 11.4's [`sys_getpriority`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_resource.c#L93-L165) for the only guest process, which is taken to run at nice 0: `PRIO_PROCESS` and `PRIO_PGRP` with 0 or its own pid (the guest is taken to lead its own process group, see `kill`) and `PRIO_USER` with 0 or its user id 0 return 0, any other id fails with `ESRCH` and any other `which` with `EINVAL`. As in FreeBSD's libc, where `getpriority` is the bare system call, errno is left unchanged on success. The nice value of a title process on the console is unverified, and the host nice of the process or of the threads `APS5_THREAD_PRIORITY=high` raises is not reported. `setpriority` accepts the same target ids (any other id fails with `ESRCH`, any other `which` with `EINVAL`), clamps the value to FreeBSD's `PRIO_MIN`-`PRIO_MAX` (-20 to 20) and stores it as the guest process's nice value, which `getpriority` returns; the host scheduling class is not changed, and whether a title process may lower the value without privilege is unverified