unix: fix Signalfd function signature on linux

The kernel raw syscall takes an additional parameter specifying
the size of the Sigset_t parameter, returns a file descriptor and sets errno.

Add a uintptr maxSize parameter, adjust the return to be (newfd int, err error).
Add the _NSIG #define and a wrapper to call with maxSize set to _C__NSIG/8 as done
in glibc/musl.

Change-Id: I277db0aab5c12364533c26ea800b7f394ec83ae4
Reviewed-on: https://go-review.googlesource.com/c/sys/+/178858
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

unix/linux/types.go

@@ -804,6 +804,8 @@ const (
 
 type Sigset_t C.sigset_t
 
+const _C__NSIG = C._NSIG
+
 type SignalfdSiginfo C.struct_signalfd_siginfo
 
 const PERF_IOC_FLAG_GROUP = C.PERF_IOC_FLAG_GROUP

unix/syscall_linux.go

@@ -1537,9 +1537,13 @@ func Setgid(uid int) (err error) {
 	return EOPNOTSUPP
 }
 
+func Signalfd(fd int, sigmask *Sigset_t, flags int) (newfd int, err error) {
+	return signalfd(fd, sigmask, _C__NSIG/8, flags)
+}
+
 //sys	Setpriority(which int, who int, prio int) (err error)
 //sys	Setxattr(path string, attr string, data []byte, flags int) (err error)
-//sys	Signalfd(fd int, mask *Sigset_t, flags int) = SYS_SIGNALFD4
+//sys	signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) = SYS_SIGNALFD4
 //sys	Statx(dirfd int, path string, flags int, mask int, stat *Statx_t) (err error)
 //sys	Sync()
 //sys	Syncfs(fd int) (err error)

unix/zsyscall_linux_386.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_amd64.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_arm.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_arm64.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_mips.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_mips64.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_mips64le.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_mipsle.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_ppc64.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_ppc64le.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_riscv64.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_s390x.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/zsyscall_linux_sparc64.go

@@ -1381,8 +1381,12 @@ func Setxattr(path string, attr string, data []byte, flags int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Signalfd(fd int, mask *Sigset_t, flags int) {
+func signalfd(fd int, sigmask *Sigset_t, maskSize uintptr, flags int) (newfd int, err error) {
-	SyscallNoError(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(mask)), uintptr(flags))
+	r0, _, e1 := Syscall6(SYS_SIGNALFD4, uintptr(fd), uintptr(unsafe.Pointer(sigmask)), uintptr(maskSize), uintptr(flags), 0, 0)
+	newfd = int(r0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
 	return
 }
 

unix/ztypes_linux_386.go

@@ -829,6 +829,8 @@ type Sigset_t struct {
 	Val [32]uint32
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_amd64.go

@@ -842,6 +842,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_arm.go

@@ -818,6 +818,8 @@ type Sigset_t struct {
 	Val [32]uint32
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_arm64.go

@@ -821,6 +821,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_mips.go

@@ -823,6 +823,8 @@ type Sigset_t struct {
 	Val [32]uint32
 }
 
+const _C__NSIG = 0x80
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_mips64.go

@@ -823,6 +823,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x80
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_mips64le.go

@@ -823,6 +823,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x80
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_mipsle.go

@@ -823,6 +823,8 @@ type Sigset_t struct {
 	Val [32]uint32
 }
 
+const _C__NSIG = 0x80
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_ppc64.go

@@ -831,6 +831,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_ppc64le.go

@@ -831,6 +831,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_riscv64.go

@@ -848,6 +848,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_s390x.go

@@ -844,6 +844,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32

unix/ztypes_linux_sparc64.go

@@ -826,6 +826,8 @@ type Sigset_t struct {
 	Val [16]uint64
 }
 
+const _C__NSIG = 0x41
+
 type SignalfdSiginfo struct {
 	Signo     uint32
 	Errno     int32