// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Linux system calls.
// This file is compiled as ordinary Go code,
// but it is also input to mksyscall,
// which parses the //sys lines and generates system call stubs.
// Note that sometimes we use a lowercase //sys name and
// wrap it in our own nicer implementation.
package syscall
import (
"internal/itoa"
runtimesyscall "internal/runtime/syscall"
"runtime"
"unsafe"
)
// Pull in entersyscall/exitsyscall for Syscall/Syscall6.
//
// Note that this can't be a push linkname because the runtime already has a
// nameless linkname to export to assembly here and in x/sys. Additionally,
// entersyscall fetches the caller PC and SP and thus can't have a wrapper
// inbetween.
//go:linkname runtime_entersyscall runtime.entersyscall
func runtime_entersyscall()
//go:linkname runtime_exitsyscall runtime.exitsyscall
func runtime_exitsyscall()
// N.B. For the Syscall functions below:
//
// //go:uintptrkeepalive because the uintptr argument may be converted pointers
// that need to be kept alive in the caller.
//
// //go:nosplit because stack copying does not account for uintptrkeepalive, so
// the stack must not grow. Stack copying cannot blindly assume that all
// uintptr arguments are pointers, because some values may look like pointers,
// but not really be pointers, and adjusting their value would break the call.
//
// //go:norace, on RawSyscall, to avoid race instrumentation if RawSyscall is
// called after fork, or from a signal handler.
//
// //go:linkname to ensure ABI wrappers are generated for external callers
// (notably x/sys/unix assembly).
//go:uintptrkeepalive
//go:nosplit
//go:norace
//go:linkname RawSyscall
func RawSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
return RawSyscall6(trap, a1, a2, a3, 0, 0, 0)
}
//go:uintptrkeepalive
//go:nosplit
//go:norace
//go:linkname RawSyscall6
func RawSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
var errno uintptr
r1, r2, errno = runtimesyscall.Syscall6(trap, a1, a2, a3, a4, a5, a6)
err = Errno(errno)
return
}
//go:uintptrkeepalive
//go:nosplit
//go:linkname Syscall
func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
runtime_entersyscall()
// N.B. Calling RawSyscall here is unsafe with atomic coverage
// instrumentation and race mode.
//
// Coverage instrumentation will add a sync/atomic call to RawSyscall.
// Race mode will add race instrumentation to sync/atomic. Race
// instrumentation requires a P, which we no longer have.
//
// RawSyscall6 is fine because it is implemented in assembly and thus
// has no coverage instrumentation.
//
// This is typically not a problem in the runtime because cmd/go avoids
// adding coverage instrumentation to the runtime in race mode.
r1, r2, err = RawSyscall6(trap, a1, a2, a3, 0, 0, 0)
runtime_exitsyscall()
return
}
//go:uintptrkeepalive
//go:nosplit
//go:linkname Syscall6
func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
runtime_entersyscall()
r1, r2, err = RawSyscall6(trap, a1, a2, a3, a4, a5, a6)
runtime_exitsyscall()
return
}
func rawSyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr)
func rawVforkSyscall(trap, a1, a2, a3 uintptr) (r1 uintptr, err Errno)
/*
* Wrapped
*/
func Access(path string, mode uint32) (err error) {
return Faccessat(_AT_FDCWD, path, mode, 0)
}
func Chmod(path string, mode uint32) (err error) {
return Fchmodat(_AT_FDCWD, path, mode, 0)
}
func Chown(path string, uid int, gid int) (err error) {
return Fchownat(_AT_FDCWD, path, uid, gid, 0)
}
func Creat(path string, mode uint32) (fd int, err error) {
return Open(path, O_CREAT|O_WRONLY|O_TRUNC, mode)
}
func EpollCreate(size int) (fd int, err error) {
if size <= 0 {
return -1, EINVAL
}
return EpollCreate1(0)
}
func isGroupMember(gid int) bool {
groups, err := Getgroups()
if err != nil {
return false
}
for _, g := range groups {
if g == gid {
return true
}
}
return false
}
func isCapDacOverrideSet() bool {
const _CAP_DAC_OVERRIDE = 1
var c caps
c.hdr.version = _LINUX_CAPABILITY_VERSION_3
_, _, err := RawSyscall(SYS_CAPGET, uintptr(unsafe.Pointer(&c.hdr)), uintptr(unsafe.Pointer(&c.data[0])), 0)
return err == 0 && c.data[0].effective&capToMask(_CAP_DAC_OVERRIDE) != 0
}
//sys faccessat(dirfd int, path string, mode uint32) (err error)
//sys faccessat2(dirfd int, path string, mode uint32, flags int) (err error) = _SYS_faccessat2
func Faccessat(dirfd int, path string, mode uint32, flags int) (err error) {
if flags == 0 {
return faccessat(dirfd, path, mode)
}
// Attempt to use the newer faccessat2, which supports flags directly,
// falling back if it doesn't exist.
//
// Don't attempt on Android, which does not allow faccessat2 through
// its seccomp policy [1] on any version of Android as of 2022-12-20.
//
// [1] https://cs.android.com/android/platform/superproject/+/master:bionic/libc/SECCOMP_BLOCKLIST_APP.TXT;l=4;drc=dbb8670dfdcc677f7e3b9262e93800fa14c4e417
if runtime.GOOS != "android" {
if err := faccessat2(dirfd, path, mode, flags); err != ENOSYS && err != EPERM {
return err
}
}
// The Linux kernel faccessat system call does not take any flags.
// The glibc faccessat implements the flags itself; see
// https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/faccessat.c;hb=HEAD
// Because people naturally expect syscall.Faccessat to act
// like C faccessat, we do the same.
if flags & ^(_AT_SYMLINK_NOFOLLOW|_AT_EACCESS) != 0 {
return EINVAL
}
var st Stat_t
if err := fstatat(dirfd, path, &st, flags&_AT_SYMLINK_NOFOLLOW); err != nil {
return err
}
mode &= 7
if mode == 0 {
return nil
}
// Fallback to checking permission bits.
var uid int
if flags&_AT_EACCESS != 0 {
uid = Geteuid()
if uid != 0 && isCapDacOverrideSet() {
// If CAP_DAC_OVERRIDE is set, file access check is
// done by the kernel in the same way as for root
// (see generic_permission() in the Linux sources).
uid = 0
}
} else {
uid = Getuid()
}
if uid == 0 {
if mode&1 == 0 {
// Root can read and write any file.
return nil
}
if st.Mode&0111 != 0 {
// Root can execute any file that anybody can execute.
return nil
}
return EACCES
}
var fmode uint32
if uint32(uid) == st.Uid {
fmode = (st.Mode >> 6) & 7
} else {
var gid int
if flags&_AT_EACCESS != 0 {
gid = Getegid()
} else {
gid = Getgid()
}
if uint32(gid) == st.Gid || isGroupMember(int(st.Gid)) {
fmode = (st.Mode >> 3) & 7
} else {
fmode = st.Mode & 7
}
}
if fmode&mode == mode {
return nil
}
return EACCES
}
//sys fchmodat(dirfd int, path string, mode uint32) (err error)
//sys fchmodat2(dirfd int, path string, mode uint32, flags int) (err error) = _SYS_fchmodat2
func Fchmodat(dirfd int, path string, mode uint32, flags int) error {
// Linux fchmodat doesn't support the flags parameter, but fchmodat2 does.
// Try fchmodat2 if flags are specified.
if flags != 0 {
err := fchmodat2(dirfd, path, mode, flags)
if err == ENOSYS {
// fchmodat2 isn't available. If the flags are known to be valid,
// return EOPNOTSUPP to indicate that fchmodat doesn't support them.
if flags&^(_AT_SYMLINK_NOFOLLOW|_AT_EMPTY_PATH) != 0 {
return EINVAL
} else if flags&(_AT_SYMLINK_NOFOLLOW|_AT_EMPTY_PATH) != 0 {
return EOPNOTSUPP
}
}
return err
}
return fchmodat(dirfd, path, mode)
}
//sys linkat(olddirfd int, oldpath string, newdirfd int, newpath string, flags int) (err error)
func Link(oldpath string, newpath string) (err error) {
return linkat(_AT_FDCWD, oldpath, _AT_FDCWD, newpath, 0)
}
func Mkdir(path string, mode uint32) (err error) {
return Mkdirat(_AT_FDCWD, path, mode)
}
func Mknod(path string, mode uint32, dev int) (err error) {
return Mknodat(_AT_FDCWD, path, mode, dev)
}
func Open(path string, mode int, perm uint32) (fd int, err error) {
return openat(_AT_FDCWD, path, mode|O_LARGEFILE, perm)
}
//sys openat(dirfd int, path string, flags int, mode uint32) (fd int, err error)
func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
return openat(dirfd, path, flags|O_LARGEFILE, mode)
}
func Pipe(p []int) error {
return Pipe2(p, 0)
}
//sysnb pipe2(p *[2]_C_int, flags int) (err error)
func Pipe2(p []int, flags int) error {
if len(p) != 2 {
return EINVAL
}
var pp [2]_C_int
err := pipe2(&pp, flags)
if err == nil {
p[0] = int(pp[0])
p[1] = int(pp[1])
}
return err
}
//sys readlinkat(dirfd int, path string, buf []byte) (n int, err error)
func Readlink(path string, buf []byte) (n int, err error) {
return readlinkat(_AT_FDCWD, path, buf)
}
func Rename(oldpath string, newpath string) (err error) {
return Renameat(_AT_FDCWD, oldpath, _AT_FDCWD, newpath)
}
func Rmdir(path string) error {
return unlinkat(_AT_FDCWD, path, _AT_REMOVEDIR)
}
//sys symlinkat(oldpath string, newdirfd int, newpath string) (err error)
func Symlink(oldpath string, newpath string) (err error) {
return symlinkat(oldpath, _AT_FDCWD, newpath)
}
func Unlink(path string) error {
return unlinkat(_AT_FDCWD, path, 0)
}
//sys unlinkat(dirfd int, path string, flags int) (err error)
func Unlinkat(dirfd int, path string) error {
return unlinkat(dirfd, path, 0)
}
func Utimes(path string, tv []Timeval) (err error) {
if len(tv) != 2 {
return EINVAL
}
return utimes(path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
}
//sys utimensat(dirfd int, path string, times *[2]Timespec, flag int) (err error)
func UtimesNano(path string, ts []Timespec) (err error) {
if len(ts) != 2 {
return EINVAL
}
return utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0)
}
func Futimesat(dirfd int, path string, tv []Timeval) (err error) {
if len(tv) != 2 {
return EINVAL
}
return futimesat(dirfd, path, (*[2]Timeval)(unsafe.Pointer(&tv[0])))
}
func Futimes(fd int, tv []Timeval) (err error) {
// Believe it or not, this is the best we can do on Linux
// (and is what glibc does).
return Utimes("/proc/self/fd/"+itoa.Itoa(fd), tv)
}
const ImplementsGetwd = true
//sys Getcwd(buf []byte) (n int, err error)
func Getwd() (wd string, err error) {
var buf [PathMax]byte
n, err := Getcwd(buf[0:])
if err != nil {
return "", err
}
// Getcwd returns the number of bytes written to buf, including the NUL.
if n < 1 || n > len(buf) || buf[n-1] != 0 {
return "", EINVAL
}
// In some cases, Linux can return a path that starts with the
// "(unreachable)" prefix, which can potentially be a valid relative
// path. To work around that, return ENOENT if path is not absolute.
if buf[0] != '/' {
return "", ENOENT
}
return string(buf[0 : n-1]), nil
}
func Getgroups() (gids []int, err error) {
n, err := getgroups(0, nil)
if err != nil {
return nil, err
}
if n == 0 {
return nil, nil
}
// Sanity check group count. Max is 1<<16 on Linux.
if n < 0 || n > 1<<20 {
return nil, EINVAL
}
a := make([]_Gid_t, n)
n, err = getgroups(n, &a[0])
if err != nil {
return nil, err
}
gids = make([]int, n)
for i, v := range a[0:n] {
gids[i] = int(v)
}
return
}
var cgo_libc_setgroups unsafe.Pointer // non-nil if cgo linked.
func Setgroups(gids []int) (err error) {
n := uintptr(len(gids))
if n == 0 {
if cgo_libc_setgroups == nil {
if _, _, e1 := AllThreadsSyscall(_SYS_setgroups, 0, 0, 0); e1 != 0 {
err = errnoErr(e1)
}
return
}
if ret := cgocaller(cgo_libc_setgroups, 0, 0); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
a := make([]_Gid_t, len(gids))
for i, v := range gids {
a[i] = _Gid_t(v)
}
if cgo_libc_setgroups == nil {
if _, _, e1 := AllThreadsSyscall(_SYS_setgroups, n, uintptr(unsafe.Pointer(&a[0])), 0); e1 != 0 {
err = errnoErr(e1)
}
return
}
if ret := cgocaller(cgo_libc_setgroups, n, uintptr(unsafe.Pointer(&a[0]))); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
type WaitStatus uint32
// Wait status is 7 bits at bottom, either 0 (exited),
// 0x7F (stopped), or a signal number that caused an exit.
// The 0x80 bit is whether there was a core dump.
// An extra number (exit code, signal causing a stop)
// is in the high bits. At least that's the idea.
// There are various irregularities. For example, the
// "continued" status is 0xFFFF, distinguishing itself
// from stopped via the core dump bit.
const (
mask = 0x7F
core = 0x80
exited = 0x00
stopped = 0x7F
shift = 8
)
func (w WaitStatus) Exited() bool { return w&mask == exited }
func (w WaitStatus) Signaled() bool { return w&mask != stopped && w&mask != exited }
func (w WaitStatus) Stopped() bool { return w&0xFF == stopped }
func (w WaitStatus) Continued() bool { return w == 0xFFFF }
func (w WaitStatus) CoreDump() bool { return w.Signaled() && w&core != 0 }
func (w WaitStatus) ExitStatus() int {
if !w.Exited() {
return -1
}
return int(w>>shift) & 0xFF
}
func (w WaitStatus) Signal() Signal {
if !w.Signaled() {
return -1
}
return Signal(w & mask)
}
func (w WaitStatus) StopSignal() Signal {
if !w.Stopped() {
return -1
}
return Signal(w>>shift) & 0xFF
}
func (w WaitStatus) TrapCause() int {
if w.StopSignal() != SIGTRAP {
return -1
}
return int(w>>shift) >> 8
}
//sys wait4(pid int, wstatus *_C_int, options int, rusage *Rusage) (wpid int, err error)
func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
var status _C_int
wpid, err = wait4(pid, &status, options, rusage)
if wstatus != nil {
*wstatus = WaitStatus(status)
}
return
}
func Mkfifo(path string, mode uint32) (err error) {
return Mknod(path, mode|S_IFIFO, 0)
}
func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {
if sa.Port < 0 || sa.Port > 0xFFFF {
return nil, 0, EINVAL
}
sa.raw.Family = AF_INET
p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
p[0] = byte(sa.Port >> 8)
p[1] = byte(sa.Port)
sa.raw.Addr = sa.Addr
return unsafe.Pointer(&sa.raw), SizeofSockaddrInet4, nil
}
func (sa *SockaddrInet6) sockaddr() (unsafe.Pointer, _Socklen, error) {
if sa.Port < 0 || sa.Port > 0xFFFF {
return nil, 0, EINVAL
}
sa.raw.Family = AF_INET6
p := (*[2]byte)(unsafe.Pointer(&sa.raw.Port))
p[0] = byte(sa.Port >> 8)
p[1] = byte(sa.Port)
sa.raw.Scope_id = sa.ZoneId
sa.raw.Addr = sa.Addr
return unsafe.Pointer(&sa.raw), SizeofSockaddrInet6, nil
}
func (sa *SockaddrUnix) sockaddr() (unsafe.Pointer, _Socklen, error) {
name := sa.Name
n := len(name)
if n > len(sa.raw.Path) {
return nil, 0, EINVAL
}
if n == len(sa.raw.Path) && name[0] != '@' {
return nil, 0, EINVAL
}
sa.raw.Family = AF_UNIX
for i := 0; i < n; i++ {
sa.raw.Path[i] = int8(name[i])
}
// length is family (uint16), name, NUL.
sl := _Socklen(2)
if n > 0 {
sl += _Socklen(n) + 1
}
if sa.raw.Path[0] == '@' || (sa.raw.Path[0] == 0 && sl > 3) {
// Check sl > 3 so we don't change unnamed socket behavior.
sa.raw.Path[0] = 0
// Don't count trailing NUL for abstract address.
sl--
}
return unsafe.Pointer(&sa.raw), sl, nil
}
type SockaddrLinklayer struct {
Protocol uint16
Ifindex int
Hatype uint16
Pkttype uint8
Halen uint8
Addr [8]byte
raw RawSockaddrLinklayer
}
func (sa *SockaddrLinklayer) sockaddr() (unsafe.Pointer, _Socklen, error) {
if sa.Ifindex < 0 || sa.Ifindex > 0x7fffffff {
return nil, 0, EINVAL
}
sa.raw.Family = AF_PACKET
sa.raw.Protocol = sa.Protocol
sa.raw.Ifindex = int32(sa.Ifindex)
sa.raw.Hatype = sa.Hatype
sa.raw.Pkttype = sa.Pkttype
sa.raw.Halen = sa.Halen
sa.raw.Addr = sa.Addr
return unsafe.Pointer(&sa.raw), SizeofSockaddrLinklayer, nil
}
type SockaddrNetlink struct {
Family uint16
Pad uint16
Pid uint32
Groups uint32
raw RawSockaddrNetlink
}
func (sa *SockaddrNetlink) sockaddr() (unsafe.Pointer, _Socklen, error) {
sa.raw.Family = AF_NETLINK
sa.raw.Pad = sa.Pad
sa.raw.Pid = sa.Pid
sa.raw.Groups = sa.Groups
return unsafe.Pointer(&sa.raw), SizeofSockaddrNetlink, nil
}
func anyToSockaddr(rsa *RawSockaddrAny) (Sockaddr, error) {
switch rsa.Addr.Family {
case AF_NETLINK:
pp := (*RawSockaddrNetlink)(unsafe.Pointer(rsa))
sa := new(SockaddrNetlink)
sa.Family = pp.Family
sa.Pad = pp.Pad
sa.Pid = pp.Pid
sa.Groups = pp.Groups
return sa, nil
case AF_PACKET:
pp := (*RawSockaddrLinklayer)(unsafe.Pointer(rsa))
sa := new(SockaddrLinklayer)
sa.Protocol = pp.Protocol
sa.Ifindex = int(pp.Ifindex)
sa.Hatype = pp.Hatype
sa.Pkttype = pp.Pkttype
sa.Halen = pp.Halen
sa.Addr = pp.Addr
return sa, nil
case AF_UNIX:
pp := (*RawSockaddrUnix)(unsafe.Pointer(rsa))
sa := new(SockaddrUnix)
if pp.Path[0] == 0 {
// "Abstract" Unix domain socket.
// Rewrite leading NUL as @ for textual display.
// (This is the standard convention.)
// Not friendly to overwrite in place,
// but the callers below don't care.
pp.Path[0] = '@'
}
// Assume path ends at NUL.
// This is not technically the Linux semantics for
// abstract Unix domain sockets--they are supposed
// to be uninterpreted fixed-size binary blobs--but
// everyone uses this convention.
n := 0
for n < len(pp.Path) && pp.Path[n] != 0 {
n++
}
sa.Name = string(unsafe.Slice((*byte)(unsafe.Pointer(&pp.Path[0])), n))
return sa, nil
case AF_INET:
pp := (*RawSockaddrInet4)(unsafe.Pointer(rsa))
sa := new(SockaddrInet4)
p := (*[2]byte)(unsafe.Pointer(&pp.Port))
sa.Port = int(p[0])<<8 + int(p[1])
sa.Addr = pp.Addr
return sa, nil
case AF_INET6:
pp := (*RawSockaddrInet6)(unsafe.Pointer(rsa))
sa := new(SockaddrInet6)
p := (*[2]byte)(unsafe.Pointer(&pp.Port))
sa.Port = int(p[0])<<8 + int(p[1])
sa.ZoneId = pp.Scope_id
sa.Addr = pp.Addr
return sa, nil
}
return nil, EAFNOSUPPORT
}
func Accept(fd int) (nfd int, sa Sockaddr, err error) {
return Accept4(fd, 0)
}
func Accept4(fd int, flags int) (nfd int, sa Sockaddr, err error) {
var rsa RawSockaddrAny
var len _Socklen = SizeofSockaddrAny
nfd, err = accept4(fd, &rsa, &len, flags)
if err != nil {
return
}
if len > SizeofSockaddrAny {
panic("RawSockaddrAny too small")
}
sa, err = anyToSockaddr(&rsa)
if err != nil {
Close(nfd)
nfd = 0
}
return
}
func Getsockname(fd int) (sa Sockaddr, err error) {
var rsa RawSockaddrAny
var len _Socklen = SizeofSockaddrAny
if err = getsockname(fd, &rsa, &len); err != nil {
return
}
return anyToSockaddr(&rsa)
}
func GetsockoptInet4Addr(fd, level, opt int) (value [4]byte, err error) {
vallen := _Socklen(4)
err = getsockopt(fd, level, opt, unsafe.Pointer(&value[0]), &vallen)
return value, err
}
func GetsockoptIPMreq(fd, level, opt int) (*IPMreq, error) {
var value IPMreq
vallen := _Socklen(SizeofIPMreq)
err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
return &value, err
}
func GetsockoptIPMreqn(fd, level, opt int) (*IPMreqn, error) {
var value IPMreqn
vallen := _Socklen(SizeofIPMreqn)
err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
return &value, err
}
func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {
var value IPv6Mreq
vallen := _Socklen(SizeofIPv6Mreq)
err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
return &value, err
}
func GetsockoptIPv6MTUInfo(fd, level, opt int) (*IPv6MTUInfo, error) {
var value IPv6MTUInfo
vallen := _Socklen(SizeofIPv6MTUInfo)
err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
return &value, err
}
func GetsockoptICMPv6Filter(fd, level, opt int) (*ICMPv6Filter, error) {
var value ICMPv6Filter
vallen := _Socklen(SizeofICMPv6Filter)
err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
return &value, err
}
func GetsockoptUcred(fd, level, opt int) (*Ucred, error) {
var value Ucred
vallen := _Socklen(SizeofUcred)
err := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
return &value, err
}
func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
}
func recvmsgRaw(fd int, p, oob []byte, flags int, rsa *RawSockaddrAny) (n, oobn int, recvflags int, err error) {
var msg Msghdr
msg.Name = (*byte)(unsafe.Pointer(rsa))
msg.Namelen = uint32(SizeofSockaddrAny)
var iov Iovec
if len(p) > 0 {
iov.Base = &p[0]
iov.SetLen(len(p))
}
var dummy byte
if len(oob) > 0 {
if len(p) == 0 {
var sockType int
sockType, err = GetsockoptInt(fd, SOL_SOCKET, SO_TYPE)
if err != nil {
return
}
// receive at least one normal byte
if sockType != SOCK_DGRAM {
iov.Base = &dummy
iov.SetLen(1)
}
}
msg.Control = &oob[0]
msg.SetControllen(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if n, err = recvmsg(fd, &msg, flags); err != nil {
return
}
oobn = int(msg.Controllen)
recvflags = int(msg.Flags)
return
}
func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
var msg Msghdr
msg.Name = (*byte)(ptr)
msg.Namelen = uint32(salen)
var iov Iovec
if len(p) > 0 {
iov.Base = &p[0]
iov.SetLen(len(p))
}
var dummy byte
if len(oob) > 0 {
if len(p) == 0 {
var sockType int
sockType, err = GetsockoptInt(fd, SOL_SOCKET, SO_TYPE)
if err != nil {
return 0, err
}
// send at least one normal byte
if sockType != SOCK_DGRAM {
iov.Base = &dummy
iov.SetLen(1)
}
}
msg.Control = &oob[0]
msg.SetControllen(len(oob))
}
msg.Iov = &iov
msg.Iovlen = 1
if n, err = sendmsg(fd, &msg, flags); err != nil {
return 0, err
}
if len(oob) > 0 && len(p) == 0 {
n = 0
}
return n, nil
}
// BindToDevice binds the socket associated with fd to device.
func BindToDevice(fd int, device string) (err error) {
return SetsockoptString(fd, SOL_SOCKET, SO_BINDTODEVICE, device)
}
//sys ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
//sys ptracePtr(request int, pid int, addr uintptr, data unsafe.Pointer) (err error) = SYS_PTRACE
func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err error) {
// The peek requests are machine-size oriented, so we wrap it
// to retrieve arbitrary-length data.
// The ptrace syscall differs from glibc's ptrace.
// Peeks returns the word in *data, not as the return value.
var buf [sizeofPtr]byte
// Leading edge. PEEKTEXT/PEEKDATA don't require aligned
// access (PEEKUSER warns that it might), but if we don't
// align our reads, we might straddle an unmapped page
// boundary and not get the bytes leading up to the page
// boundary.
n := 0
if addr%sizeofPtr != 0 {
err = ptracePtr(req, pid, addr-addr%sizeofPtr, unsafe.Pointer(&buf[0]))
if err != nil {
return 0, err
}
n += copy(out, buf[addr%sizeofPtr:])
out = out[n:]
}
// Remainder.
for len(out) > 0 {
// We use an internal buffer to guarantee alignment.
// It's not documented if this is necessary, but we're paranoid.
err = ptracePtr(req, pid, addr+uintptr(n), unsafe.Pointer(&buf[0]))
if err != nil {
return n, err
}
copied := copy(out, buf[0:])
n += copied
out = out[copied:]
}
return n, nil
}
func PtracePeekText(pid int, addr uintptr, out []byte) (count int, err error) {
return ptracePeek(PTRACE_PEEKTEXT, pid, addr, out)
}
func PtracePeekData(pid int, addr uintptr, out []byte) (count int, err error) {
return ptracePeek(PTRACE_PEEKDATA, pid, addr, out)
}
func ptracePoke(pokeReq int, peekReq int, pid int, addr uintptr, data []byte) (count int, err error) {
// As for ptracePeek, we need to align our accesses to deal
// with the possibility of straddling an invalid page.
// Leading edge.
n := 0
if addr%sizeofPtr != 0 {
var buf [sizeofPtr]byte
err = ptracePtr(peekReq, pid, addr-addr%sizeofPtr, unsafe.Pointer(&buf[0]))
if err != nil {
return 0, err
}
n += copy(buf[addr%sizeofPtr:], data)
word := *((*uintptr)(unsafe.Pointer(&buf[0])))
err = ptrace(pokeReq, pid, addr-addr%sizeofPtr, word)
if err != nil {
return 0, err
}
data = data[n:]
}
// Interior.
for len(data) > sizeofPtr {
word := *((*uintptr)(unsafe.Pointer(&data[0])))
err = ptrace(pokeReq, pid, addr+uintptr(n), word)
if err != nil {
return n, err
}
n += sizeofPtr
data = data[sizeofPtr:]
}
// Trailing edge.
if len(data) > 0 {
var buf [sizeofPtr]byte
err = ptracePtr(peekReq, pid, addr+uintptr(n), unsafe.Pointer(&buf[0]))
if err != nil {
return n, err
}
copy(buf[0:], data)
word := *((*uintptr)(unsafe.Pointer(&buf[0])))
err = ptrace(pokeReq, pid, addr+uintptr(n), word)
if err != nil {
return n, err
}
n += len(data)
}
return n, nil
}
func PtracePokeText(pid int, addr uintptr, data []byte) (count int, err error) {
return ptracePoke(PTRACE_POKETEXT, PTRACE_PEEKTEXT, pid, addr, data)
}
func PtracePokeData(pid int, addr uintptr, data []byte) (count int, err error) {
return ptracePoke(PTRACE_POKEDATA, PTRACE_PEEKDATA, pid, addr, data)
}
const (
_NT_PRSTATUS = 1
)
func PtraceGetRegs(pid int, regsout *PtraceRegs) (err error) {
var iov Iovec
iov.Base = (*byte)(unsafe.Pointer(regsout))
iov.SetLen(int(unsafe.Sizeof(*regsout)))
return ptracePtr(PTRACE_GETREGSET, pid, uintptr(_NT_PRSTATUS), unsafe.Pointer(&iov))
}
func PtraceSetRegs(pid int, regs *PtraceRegs) (err error) {
var iov Iovec
iov.Base = (*byte)(unsafe.Pointer(regs))
iov.SetLen(int(unsafe.Sizeof(*regs)))
return ptracePtr(PTRACE_SETREGSET, pid, uintptr(_NT_PRSTATUS), unsafe.Pointer(&iov))
}
func PtraceSetOptions(pid int, options int) (err error) {
return ptrace(PTRACE_SETOPTIONS, pid, 0, uintptr(options))
}
func PtraceGetEventMsg(pid int) (msg uint, err error) {
var data _C_long
err = ptracePtr(PTRACE_GETEVENTMSG, pid, 0, unsafe.Pointer(&data))
msg = uint(data)
return
}
func PtraceCont(pid int, signal int) (err error) {
return ptrace(PTRACE_CONT, pid, 0, uintptr(signal))
}
func PtraceSyscall(pid int, signal int) (err error) {
return ptrace(PTRACE_SYSCALL, pid, 0, uintptr(signal))
}
func PtraceSingleStep(pid int) (err error) { return ptrace(PTRACE_SINGLESTEP, pid, 0, 0) }
func PtraceAttach(pid int) (err error) { return ptrace(PTRACE_ATTACH, pid, 0, 0) }
func PtraceDetach(pid int) (err error) { return ptrace(PTRACE_DETACH, pid, 0, 0) }
//sys reboot(magic1 uint, magic2 uint, cmd int, arg string) (err error)
func Reboot(cmd int) (err error) {
return reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2, cmd, "")
}
func ReadDirent(fd int, buf []byte) (n int, err error) {
return Getdents(fd, buf)
}
func direntIno(buf []byte) (uint64, bool) {
return readInt(buf, unsafe.Offsetof(Dirent{}.Ino), unsafe.Sizeof(Dirent{}.Ino))
}
func direntReclen(buf []byte) (uint64, bool) {
return readInt(buf, unsafe.Offsetof(Dirent{}.Reclen), unsafe.Sizeof(Dirent{}.Reclen))
}
func direntNamlen(buf []byte) (uint64, bool) {
reclen, ok := direntReclen(buf)
if !ok {
return 0, false
}
return reclen - uint64(unsafe.Offsetof(Dirent{}.Name)), true
}
//sys mount(source string, target string, fstype string, flags uintptr, data *byte) (err error)
func Mount(source string, target string, fstype string, flags uintptr, data string) (err error) {
// Certain file systems get rather angry and EINVAL if you give
// them an empty string of data, rather than NULL.
if data == "" {
return mount(source, target, fstype, flags, nil)
}
datap, err := BytePtrFromString(data)
if err != nil {
return err
}
return mount(source, target, fstype, flags, datap)
}
// Sendto
// Recvfrom
// Socketpair
/*
* Direct access
*/
//sys Acct(path string) (err error)
//sys Adjtimex(buf *Timex) (state int, err error)
//sys Chdir(path string) (err error)
//sys Chroot(path string) (err error)
//sys Close(fd int) (err error)
//sys Dup(oldfd int) (fd int, err error)
//sys Dup3(oldfd int, newfd int, flags int) (err error)
//sysnb EpollCreate1(flag int) (fd int, err error)
//sysnb EpollCtl(epfd int, op int, fd int, event *EpollEvent) (err error)
//sys Fallocate(fd int, mode uint32, off int64, len int64) (err error)
//sys Fchdir(fd int) (err error)
//sys Fchmod(fd int, mode uint32) (err error)
//sys Fchownat(dirfd int, path string, uid int, gid int, flags int) (err error)
//sys fcntl(fd int, cmd int, arg int) (val int, err error)
//sys Fdatasync(fd int) (err error)
//sys Flock(fd int, how int) (err error)
//sys Fsync(fd int) (err error)
//sys Getdents(fd int, buf []byte) (n int, err error) = SYS_GETDENTS64
//sysnb Getpgid(pid int) (pgid int, err error)
func Getpgrp() (pid int) {
pid, _ = Getpgid(0)
return
}
//sysnb Getpid() (pid int)
//sysnb Getppid() (ppid int)
//sys Getpriority(which int, who int) (prio int, err error)
//sysnb Getrusage(who int, rusage *Rusage) (err error)
//sysnb Gettid() (tid int)
//sys Getxattr(path string, attr string, dest []byte) (sz int, err error)
//sys InotifyAddWatch(fd int, pathname string, mask uint32) (watchdesc int, err error)
//sysnb InotifyInit1(flags int) (fd int, err error)
//sysnb InotifyRmWatch(fd int, watchdesc uint32) (success int, err error)
//sysnb Kill(pid int, sig Signal) (err error)
//sys Klogctl(typ int, buf []byte) (n int, err error) = SYS_SYSLOG
//sys Listxattr(path string, dest []byte) (sz int, err error)
//sys Mkdirat(dirfd int, path string, mode uint32) (err error)
//sys Mknodat(dirfd int, path string, mode uint32, dev int) (err error)
//sys Nanosleep(time *Timespec, leftover *Timespec) (err error)
//sys PivotRoot(newroot string, putold string) (err error) = SYS_PIVOT_ROOT
//sysnb prlimit1(pid int, resource int, newlimit *Rlimit, old *Rlimit) (err error) = SYS_PRLIMIT64
//sys read(fd int, p []byte) (n int, err error)
//sys Removexattr(path string, attr string) (err error)
//sys Setdomainname(p []byte) (err error)
//sys Sethostname(p []byte) (err error)
//sysnb Setpgid(pid int, pgid int) (err error)
//sysnb Setsid() (pid int, err error)
//sysnb Settimeofday(tv *Timeval) (err error)
// Provided by runtime.syscall_runtime_doAllThreadsSyscall which stops the
// world and invokes the syscall on each OS thread. Once this function returns,
// all threads are in sync.
//
//go:uintptrescapes
func runtime_doAllThreadsSyscall(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr)
// AllThreadsSyscall performs a syscall on each OS thread of the Go
// runtime. It first invokes the syscall on one thread. Should that
// invocation fail, it returns immediately with the error status.
// Otherwise, it invokes the syscall on all of the remaining threads
// in parallel. It will terminate the program if it observes any
// invoked syscall's return value differs from that of the first
// invocation.
//
// AllThreadsSyscall is intended for emulating simultaneous
// process-wide state changes that require consistently modifying
// per-thread state of the Go runtime.
//
// AllThreadsSyscall is unaware of any threads that are launched
// explicitly by cgo linked code, so the function always returns
// [ENOTSUP] in binaries that use cgo.
//
//go:uintptrescapes
func AllThreadsSyscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
if cgo_libc_setegid != nil {
return minus1, minus1, ENOTSUP
}
r1, r2, errno := runtime_doAllThreadsSyscall(trap, a1, a2, a3, 0, 0, 0)
return r1, r2, Errno(errno)
}
// AllThreadsSyscall6 is like [AllThreadsSyscall], but extended to six
// arguments.
//
//go:uintptrescapes
func AllThreadsSyscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
if cgo_libc_setegid != nil {
return minus1, minus1, ENOTSUP
}
r1, r2, errno := runtime_doAllThreadsSyscall(trap, a1, a2, a3, a4, a5, a6)
return r1, r2, Errno(errno)
}
// linked by runtime.cgocall.go
//
//go:uintptrescapes
func cgocaller(unsafe.Pointer, ...uintptr) uintptr
var cgo_libc_setegid unsafe.Pointer // non-nil if cgo linked.
const minus1 = ^uintptr(0)
func Setegid(egid int) (err error) {
if cgo_libc_setegid == nil {
if _, _, e1 := AllThreadsSyscall(SYS_SETRESGID, minus1, uintptr(egid), minus1); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setegid, uintptr(egid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_seteuid unsafe.Pointer // non-nil if cgo linked.
func Seteuid(euid int) (err error) {
if cgo_libc_seteuid == nil {
if _, _, e1 := AllThreadsSyscall(SYS_SETRESUID, minus1, uintptr(euid), minus1); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_seteuid, uintptr(euid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_setgid unsafe.Pointer // non-nil if cgo linked.
func Setgid(gid int) (err error) {
if cgo_libc_setgid == nil {
if _, _, e1 := AllThreadsSyscall(sys_SETGID, uintptr(gid), 0, 0); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setgid, uintptr(gid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_setregid unsafe.Pointer // non-nil if cgo linked.
func Setregid(rgid, egid int) (err error) {
if cgo_libc_setregid == nil {
if _, _, e1 := AllThreadsSyscall(sys_SETREGID, uintptr(rgid), uintptr(egid), 0); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setregid, uintptr(rgid), uintptr(egid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_setresgid unsafe.Pointer // non-nil if cgo linked.
func Setresgid(rgid, egid, sgid int) (err error) {
if cgo_libc_setresgid == nil {
if _, _, e1 := AllThreadsSyscall(sys_SETRESGID, uintptr(rgid), uintptr(egid), uintptr(sgid)); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setresgid, uintptr(rgid), uintptr(egid), uintptr(sgid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_setresuid unsafe.Pointer // non-nil if cgo linked.
func Setresuid(ruid, euid, suid int) (err error) {
if cgo_libc_setresuid == nil {
if _, _, e1 := AllThreadsSyscall(sys_SETRESUID, uintptr(ruid), uintptr(euid), uintptr(suid)); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setresuid, uintptr(ruid), uintptr(euid), uintptr(suid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_setreuid unsafe.Pointer // non-nil if cgo linked.
func Setreuid(ruid, euid int) (err error) {
if cgo_libc_setreuid == nil {
if _, _, e1 := AllThreadsSyscall(sys_SETREUID, uintptr(ruid), uintptr(euid), 0); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setreuid, uintptr(ruid), uintptr(euid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
var cgo_libc_setuid unsafe.Pointer // non-nil if cgo linked.
func Setuid(uid int) (err error) {
if cgo_libc_setuid == nil {
if _, _, e1 := AllThreadsSyscall(sys_SETUID, uintptr(uid), 0, 0); e1 != 0 {
err = errnoErr(e1)
}
} else if ret := cgocaller(cgo_libc_setuid, uintptr(uid)); ret != 0 {
err = errnoErr(Errno(ret))
}
return
}
//sys Setpriority(which int, who int, prio int) (err error)
//sys Setxattr(path string, attr string, data []byte, flags int) (err error)
//sys Sync()
//sysnb Sysinfo(info *Sysinfo_t) (err error)
//sys Tee(rfd int, wfd int, len int, flags int) (n int64, err error)
//sysnb Tgkill(tgid int, tid int, sig Signal) (err error)
//sysnb Times(tms *Tms) (ticks uintptr, err error)
//sysnb Umask(mask int) (oldmask int)
//sysnb Uname(buf *Utsname) (err error)
//sys Unmount(target string, flags int) (err error) = SYS_UMOUNT2
//sys Unshare(flags int) (err error)
//sys write(fd int, p []byte) (n int, err error)
//sys exitThread(code int) (err error) = SYS_EXIT
//sys readlen(fd int, p *byte, np int) (n int, err error) = SYS_READ
// mmap varies by architecture; see syscall_linux_*.go.
//sys munmap(addr uintptr, length uintptr) (err error)
var mapper = &mmapper{
active: make(map[*byte][]byte),
mmap: mmap,
munmap: munmap,
}
func Mmap(fd int, offset int64, length int, prot int, flags int) (data []byte, err error) {
return mapper.Mmap(fd, offset, length, prot, flags)
}
func Munmap(b []byte) (err error) {
return mapper.Munmap(b)
}
//sys Madvise(b []byte, advice int) (err error)
//sys Mprotect(b []byte, prot int) (err error)
//sys Mlock(b []byte) (err error)
//sys Munlock(b []byte) (err error)
//sys Mlockall(flags int) (err error)
//sys Munlockall() (err error)
func Getrlimit(resource int, rlim *Rlimit) (err error) {
// prlimit1 is the same as prlimit when newlimit == nil
return prlimit1(0, resource, nil, rlim)
}
// setrlimit sets a resource limit.
// The Setrlimit function is in rlimit.go, and calls this one.
func setrlimit(resource int, rlim *Rlimit) (err error) {
return prlimit1(0, resource, rlim, nil)
}
// prlimit changes a resource limit. We use a single definition so that
// we can tell StartProcess to not restore the original NOFILE limit.
//
// golang.org/x/sys linknames prlimit.
// Do not remove or change the type signature.
//
//go:linkname prlimit
func prlimit(pid int, resource int, newlimit *Rlimit, old *Rlimit) (err error) {
err = prlimit1(pid, resource, newlimit, old)
if err == nil && newlimit != nil && resource == RLIMIT_NOFILE && (pid == 0 || pid == Getpid()) {
origRlimitNofile.Store(nil)
}
return err
}