...
Run Format

Source file src/runtime/os_freebsd.go

Documentation: runtime

  // Copyright 2011 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.
  
  package runtime
  
  import (
  	"runtime/internal/sys"
  	"unsafe"
  )
  
  type mOS struct{}
  
  //go:noescape
  func thr_new(param *thrparam, size int32)
  
  //go:noescape
  func sigaltstack(new, old *stackt)
  
  //go:noescape
  func sigaction(sig uint32, new, old *sigactiont)
  
  //go:noescape
  func sigprocmask(how int32, new, old *sigset)
  
  //go:noescape
  func setitimer(mode int32, new, old *itimerval)
  
  //go:noescape
  func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32
  
  //go:noescape
  func getrlimit(kind int32, limit unsafe.Pointer) int32
  func raise(sig uint32)
  func raiseproc(sig uint32)
  
  //go:noescape
  func sys_umtx_op(addr *uint32, mode int32, val uint32, uaddr1 uintptr, ut *umtx_time) int32
  
  func osyield()
  
  // From FreeBSD's <sys/sysctl.h>
  const (
  	_CTL_HW      = 6
  	_HW_PAGESIZE = 7
  )
  
  var sigset_all = sigset{[4]uint32{^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)}}
  
  // Undocumented numbers from FreeBSD's lib/libc/gen/sysctlnametomib.c.
  const (
  	_CTL_QUERY     = 0
  	_CTL_QUERY_MIB = 3
  )
  
  // sysctlnametomib fill mib with dynamically assigned sysctl entries of name,
  // return count of effected mib slots, return 0 on error.
  func sysctlnametomib(name []byte, mib *[_CTL_MAXNAME]uint32) uint32 {
  	oid := [2]uint32{_CTL_QUERY, _CTL_QUERY_MIB}
  	miblen := uintptr(_CTL_MAXNAME)
  	if sysctl(&oid[0], 2, (*byte)(unsafe.Pointer(mib)), &miblen, (*byte)(unsafe.Pointer(&name[0])), (uintptr)(len(name))) < 0 {
  		return 0
  	}
  	miblen /= unsafe.Sizeof(uint32(0))
  	if miblen <= 0 {
  		return 0
  	}
  	return uint32(miblen)
  }
  
  const (
  	_CPU_SETSIZE_MAX = 32 // Limited by _MaxGomaxprocs(256) in runtime2.go.
  	_CPU_CURRENT_PID = -1 // Current process ID.
  )
  
  //go:noescape
  func cpuset_getaffinity(level int, which int, id int64, size int, mask *byte) int32
  
  func getncpu() int32 {
  	var mask [_CPU_SETSIZE_MAX]byte
  	var mib [_CTL_MAXNAME]uint32
  
  	// According to FreeBSD's /usr/src/sys/kern/kern_cpuset.c,
  	// cpuset_getaffinity return ERANGE when provided buffer size exceed the limits in kernel.
  	// Querying kern.smp.maxcpus to calculate maximum buffer size.
  	// See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200802
  
  	// Variable kern.smp.maxcpus introduced at Dec 23 2003, revision 123766,
  	// with dynamically assigned sysctl entries.
  	miblen := sysctlnametomib([]byte("kern.smp.maxcpus"), &mib)
  	if miblen == 0 {
  		return 1
  	}
  
  	// Query kern.smp.maxcpus.
  	dstsize := uintptr(4)
  	maxcpus := uint32(0)
  	if sysctl(&mib[0], miblen, (*byte)(unsafe.Pointer(&maxcpus)), &dstsize, nil, 0) != 0 {
  		return 1
  	}
  
  	size := maxcpus / _NBBY
  	ptrsize := uint32(unsafe.Sizeof(uintptr(0)))
  	if size < ptrsize {
  		size = ptrsize
  	}
  	if size > _CPU_SETSIZE_MAX {
  		return 1
  	}
  
  	if cpuset_getaffinity(_CPU_LEVEL_WHICH, _CPU_WHICH_PID, _CPU_CURRENT_PID,
  		int(size), (*byte)(unsafe.Pointer(&mask[0]))) != 0 {
  		return 1
  	}
  	n := int32(0)
  	for _, v := range mask[:size] {
  		for v != 0 {
  			n += int32(v & 1)
  			v >>= 1
  		}
  	}
  	if n == 0 {
  		return 1
  	}
  	return n
  }
  
  func getPageSize() uintptr {
  	mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
  	out := uint32(0)
  	nout := unsafe.Sizeof(out)
  	ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
  	if ret >= 0 {
  		return uintptr(out)
  	}
  	return 0
  }
  
  // FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
  // thus the code is largely similar. See Linux implementation
  // and lock_futex.go for comments.
  
  //go:nosplit
  func futexsleep(addr *uint32, val uint32, ns int64) {
  	systemstack(func() {
  		futexsleep1(addr, val, ns)
  	})
  }
  
  func futexsleep1(addr *uint32, val uint32, ns int64) {
  	var utp *umtx_time
  	if ns >= 0 {
  		var ut umtx_time
  		ut._clockid = _CLOCK_MONOTONIC
  		ut._timeout.set_sec(int64(timediv(ns, 1000000000, (*int32)(unsafe.Pointer(&ut._timeout.tv_nsec)))))
  		utp = &ut
  	}
  	ret := sys_umtx_op(addr, _UMTX_OP_WAIT_UINT_PRIVATE, val, unsafe.Sizeof(*utp), utp)
  	if ret >= 0 || ret == -_EINTR {
  		return
  	}
  	print("umtx_wait addr=", addr, " val=", val, " ret=", ret, "\n")
  	*(*int32)(unsafe.Pointer(uintptr(0x1005))) = 0x1005
  }
  
  //go:nosplit
  func futexwakeup(addr *uint32, cnt uint32) {
  	ret := sys_umtx_op(addr, _UMTX_OP_WAKE_PRIVATE, cnt, 0, nil)
  	if ret >= 0 {
  		return
  	}
  
  	systemstack(func() {
  		print("umtx_wake_addr=", addr, " ret=", ret, "\n")
  	})
  }
  
  func thr_start()
  
  // May run with m.p==nil, so write barriers are not allowed.
  //go:nowritebarrier
  func newosproc(mp *m, stk unsafe.Pointer) {
  	if false {
  		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " thr_start=", funcPC(thr_start), " id=", mp.id, " ostk=", &mp, "\n")
  	}
  
  	// NOTE(rsc): This code is confused. stackbase is the top of the stack
  	// and is equal to stk. However, it's working, so I'm not changing it.
  	param := thrparam{
  		start_func: funcPC(thr_start),
  		arg:        unsafe.Pointer(mp),
  		stack_base: mp.g0.stack.hi,
  		stack_size: uintptr(stk) - mp.g0.stack.hi,
  		child_tid:  unsafe.Pointer(&mp.procid),
  		parent_tid: nil,
  		tls_base:   unsafe.Pointer(&mp.tls[0]),
  		tls_size:   unsafe.Sizeof(mp.tls),
  	}
  
  	var oset sigset
  	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
  	// TODO: Check for error.
  	thr_new(&param, int32(unsafe.Sizeof(param)))
  	sigprocmask(_SIG_SETMASK, &oset, nil)
  }
  
  func osinit() {
  	ncpu = getncpu()
  	physPageSize = getPageSize()
  }
  
  var urandom_dev = []byte("/dev/urandom\x00")
  
  //go:nosplit
  func getRandomData(r []byte) {
  	fd := open(&urandom_dev[0], 0 /* O_RDONLY */, 0)
  	n := read(fd, unsafe.Pointer(&r[0]), int32(len(r)))
  	closefd(fd)
  	extendRandom(r, int(n))
  }
  
  func goenvs() {
  	goenvs_unix()
  }
  
  // Called to initialize a new m (including the bootstrap m).
  // Called on the parent thread (main thread in case of bootstrap), can allocate memory.
  func mpreinit(mp *m) {
  	mp.gsignal = malg(32 * 1024)
  	mp.gsignal.m = mp
  }
  
  // Called to initialize a new m (including the bootstrap m).
  // Called on the new thread, cannot allocate memory.
  func minit() {
  	// m.procid is a uint64, but thr_new writes a uint32 on 32-bit systems.
  	// Fix it up. (Only matters on big-endian, but be clean anyway.)
  	if sys.PtrSize == 4 {
  		_g_ := getg()
  		_g_.m.procid = uint64(*(*uint32)(unsafe.Pointer(&_g_.m.procid)))
  	}
  
  	// On FreeBSD before about April 2017 there was a bug such
  	// that calling execve from a thread other than the main
  	// thread did not reset the signal stack. That would confuse
  	// minitSignals, which calls minitSignalStack, which checks
  	// whether there is currently a signal stack and uses it if
  	// present. To avoid this confusion, explicitly disable the
  	// signal stack on the main thread when not running in a
  	// library. This can be removed when we are confident that all
  	// FreeBSD users are running a patched kernel. See issue #15658.
  	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
  		st := stackt{ss_flags: _SS_DISABLE}
  		sigaltstack(&st, nil)
  	}
  
  	minitSignals()
  }
  
  // Called from dropm to undo the effect of an minit.
  //go:nosplit
  func unminit() {
  	unminitSignals()
  }
  
  func memlimit() uintptr {
  	/*
  		TODO: Convert to Go when something actually uses the result.
  		Rlimit rl;
  		extern byte runtime·text[], runtime·end[];
  		uintptr used;
  
  		if(runtime·getrlimit(RLIMIT_AS, &rl) != 0)
  			return 0;
  		if(rl.rlim_cur >= 0x7fffffff)
  			return 0;
  
  		// Estimate our VM footprint excluding the heap.
  		// Not an exact science: use size of binary plus
  		// some room for thread stacks.
  		used = runtime·end - runtime·text + (64<<20);
  		if(used >= rl.rlim_cur)
  			return 0;
  
  		// If there's not at least 16 MB left, we're probably
  		// not going to be able to do much. Treat as no limit.
  		rl.rlim_cur -= used;
  		if(rl.rlim_cur < (16<<20))
  			return 0;
  
  		return rl.rlim_cur - used;
  	*/
  
  	return 0
  }
  
  func sigtramp()
  
  type sigactiont struct {
  	sa_handler uintptr
  	sa_flags   int32
  	sa_mask    sigset
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func setsig(i uint32, fn uintptr) {
  	var sa sigactiont
  	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTART
  	sa.sa_mask = sigset_all
  	if fn == funcPC(sighandler) {
  		fn = funcPC(sigtramp)
  	}
  	sa.sa_handler = fn
  	sigaction(i, &sa, nil)
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func setsigstack(i uint32) {
  	throw("setsigstack")
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func getsig(i uint32) uintptr {
  	var sa sigactiont
  	sigaction(i, nil, &sa)
  	return sa.sa_handler
  }
  
  // setSignaltstackSP sets the ss_sp field of a stackt.
  //go:nosplit
  func setSignalstackSP(s *stackt, sp uintptr) {
  	s.ss_sp = sp
  }
  
  //go:nosplit
  //go:nowritebarrierrec
  func sigaddset(mask *sigset, i int) {
  	mask.__bits[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
  }
  
  func sigdelset(mask *sigset, i int) {
  	mask.__bits[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
  }
  
  func (c *sigctxt) fixsigcode(sig uint32) {
  }
  

View as plain text