unix: add SchedSetAttr and SchedGetAttr for Linux

Add wrappers for sched_getattr(2) and sched_setattr(2), as well as
various SCHED_ values usable for these.

The kludge in linux/types.go is needed so we can include both
linux/sched/types.h (for struct sched_attr) and sched.h (for a few
defines from include/bits/cpu-set.h).

Unfortunately, they both define struct sched_param, thus the need to
mask one of the definitions.

Change-Id: I3e13cf49ccef7ae81a75d33826d18de84a52106d
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Reviewed-on: https://go-review.googlesource.com/c/sys/+/516756
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>

unix/linux/types.go

@@ -138,6 +138,11 @@ struct termios2 {
 #include <linux/random.h>
 #include <linux/rtc.h>
 #include <linux/rtnetlink.h>
+// This is to avoid a conflict of struct sched_param being defined by
+// both the kernel and the glibc (sched.h) headers.
+#define sched_param kernel_sched_param
+#include <linux/sched/types.h>
+#undef kernel_sched_param
 #include <linux/shm.h>
 #include <linux/socket.h>
 #include <linux/stat.h>
@@ -5796,3 +5801,7 @@ const (
 	RISCV_HWPROBE_MISALIGNED_UNSUPPORTED = C.RISCV_HWPROBE_MISALIGNED_UNSUPPORTED
 	RISCV_HWPROBE_MISALIGNED_MASK        = C.RISCV_HWPROBE_MISALIGNED_MASK
 )
+
+type SchedAttr C.struct_sched_attr
+
+const SizeofSchedAttr = C.sizeof_struct_sched_attr

unix/mkerrors.sh

@@ -583,6 +583,7 @@ ccflags="$@"
 		$2 ~ /^PERF_/ ||
 		$2 ~ /^SECCOMP_MODE_/ ||
 		$2 ~ /^SEEK_/ ||
+		$2 ~ /^SCHED_/ ||
 		$2 ~ /^SPLICE_/ ||
 		$2 ~ /^SYNC_FILE_RANGE_/ ||
 		$2 !~ /IOC_MAGIC/ &&

unix/syscall_linux.go

@@ -2471,6 +2471,29 @@ func Pselect(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timespec, sigmask *
 	return pselect6(nfd, r, w, e, mutableTimeout, kernelMask)
 }
 
+//sys	schedSetattr(pid int, attr *SchedAttr, flags uint) (err error)
+//sys	schedGetattr(pid int, attr *SchedAttr, size uint, flags uint) (err error)
+
+// SchedSetAttr is a wrapper for sched_setattr(2) syscall.
+// https://man7.org/linux/man-pages/man2/sched_setattr.2.html
+func SchedSetAttr(pid int, attr *SchedAttr, flags uint) error {
+	if attr == nil {
+		return EINVAL
+	}
+	attr.Size = SizeofSchedAttr
+	return schedSetattr(pid, attr, flags)
+}
+
+// SchedGetAttr is a wrapper for sched_getattr(2) syscall.
+// https://man7.org/linux/man-pages/man2/sched_getattr.2.html
+func SchedGetAttr(pid int, flags uint) (*SchedAttr, error) {
+	attr := &SchedAttr{}
+	if err := schedGetattr(pid, attr, SizeofSchedAttr, flags); err != nil {
+		return nil, err
+	}
+	return attr, nil
+}
+
 /*
  * Unimplemented
  */

unix/zerrors_linux.go

@@ -2821,6 +2821,23 @@ const (
 	RWF_SUPPORTED                               = 0x1f
 	RWF_SYNC                                    = 0x4
 	RWF_WRITE_LIFE_NOT_SET                      = 0x0
+	SCHED_BATCH                                 = 0x3
+	SCHED_DEADLINE                              = 0x6
+	SCHED_FIFO                                  = 0x1
+	SCHED_FLAG_ALL                              = 0x7f
+	SCHED_FLAG_DL_OVERRUN                       = 0x4
+	SCHED_FLAG_KEEP_ALL                         = 0x18
+	SCHED_FLAG_KEEP_PARAMS                      = 0x10
+	SCHED_FLAG_KEEP_POLICY                      = 0x8
+	SCHED_FLAG_RECLAIM                          = 0x2
+	SCHED_FLAG_RESET_ON_FORK                    = 0x1
+	SCHED_FLAG_UTIL_CLAMP                       = 0x60
+	SCHED_FLAG_UTIL_CLAMP_MAX                   = 0x40
+	SCHED_FLAG_UTIL_CLAMP_MIN                   = 0x20
+	SCHED_IDLE                                  = 0x5
+	SCHED_NORMAL                                = 0x0
+	SCHED_RESET_ON_FORK                         = 0x40000000
+	SCHED_RR                                    = 0x2
 	SCM_CREDENTIALS                             = 0x2
 	SCM_RIGHTS                                  = 0x1
 	SCM_TIMESTAMP                               = 0x1d

unix/zsyscall_linux.go

@@ -2197,3 +2197,23 @@ func getresgid(rgid *_C_int, egid *_C_int, sgid *_C_int) {
 	RawSyscallNoError(SYS_GETRESGID, uintptr(unsafe.Pointer(rgid)), uintptr(unsafe.Pointer(egid)), uintptr(unsafe.Pointer(sgid)))
 	return
 }
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func schedSetattr(pid int, attr *SchedAttr, flags uint) (err error) {
+	_, _, e1 := Syscall(SYS_SCHED_SETATTR, uintptr(pid), uintptr(unsafe.Pointer(attr)), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func schedGetattr(pid int, attr *SchedAttr, size uint, flags uint) (err error) {
+	_, _, e1 := Syscall6(SYS_SCHED_GETATTR, uintptr(pid), uintptr(unsafe.Pointer(attr)), uintptr(size), uintptr(flags), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}

unix/ztypes_linux.go

@@ -5868,3 +5868,18 @@ const (
 	VIRTIO_NET_HDR_GSO_UDP_L4 = 0x5
 	VIRTIO_NET_HDR_GSO_ECN    = 0x80
 )
+
+type SchedAttr struct {
+	Size     uint32
+	Policy   uint32
+	Flags    uint64
+	Nice     int32
+	Priority uint32
+	Runtime  uint64
+	Deadline uint64
+	Period   uint64
+	Util_min uint32
+	Util_max uint32
+}
+
+const SizeofSchedAttr = 0x38