src/pkg/runtime/os

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This source file includes following definitions.
getncpu
runtime·futexsleep
runtime·futexwakeup
runtime·newosproc
runtime·osinit
runtime·get_random_data
runtime·goenvs
runtime·mpreinit
runtime·minit
runtime·unminit
runtime·sigpanic
runtime·memlimit
runtime·setsig
runtime·getsig
runtime·signalstack
runtime·unblocksignals
// 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.

#include "runtime.h"
#include "defs_GOOS_GOARCH.h"
#include "os_GOOS.h"
#include "signal_unix.h"
#include "stack.h"
#include "../../cmd/ld/textflag.h"

extern SigTab runtime·sigtab[];
extern int32 runtime·sys_umtx_op(uint32*, int32, uint32, void*, void*);

// From FreeBSD's <sys/sysctl.h>
#define CTL_HW  6
#define HW_NCPU 3

static Sigset sigset_none;
static Sigset sigset_all = { ~(uint32)0, ~(uint32)0, ~(uint32)0, ~(uint32)0, };

static int32
getncpu(void)
{
        uint32 mib[2];
        uint32 out;
        int32 ret;
        uintptr nout;

        // Fetch hw.ncpu via sysctl.
        mib[0] = CTL_HW;
        mib[1] = HW_NCPU;
        nout = sizeof out;
        out = 0;
        ret = runtime·sysctl(mib, 2, (byte*)&out, &nout, nil, 0);
        if(ret >= 0)
                return out;
        else
                return 1;
}

// FreeBSD's umtx_op syscall is effectively the same as Linux's futex, and
// thus the code is largely similar. See linux/thread.c and lock_futex.c for comments.

#pragma textflag NOSPLIT
void
runtime·futexsleep(uint32 *addr, uint32 val, int64 ns)
{
        int32 ret;
        Timespec ts;

        if(ns < 0) {
                ret = runtime·sys_umtx_op(addr, UMTX_OP_WAIT_UINT_PRIVATE, val, nil, nil);
                if(ret >= 0 || ret == -EINTR)
                        return;
                goto fail;
        }
        // NOTE: tv_nsec is int64 on amd64, so this assumes a little-endian system.
        ts.tv_nsec = 0;
        ts.tv_sec = runtime·timediv(ns, 1000000000, (int32*)&ts.tv_nsec);
        ret = runtime·sys_umtx_op(addr, UMTX_OP_WAIT_UINT_PRIVATE, val, nil, &ts);
        if(ret >= 0 || ret == -EINTR)
                return;

fail:
        runtime·prints("umtx_wait addr=");
        runtime·printpointer(addr);
        runtime·prints(" val=");
        runtime·printint(val);
        runtime·prints(" ret=");
        runtime·printint(ret);
        runtime·prints("\n");
        *(int32*)0x1005 = 0x1005;
}

void
runtime·futexwakeup(uint32 *addr, uint32 cnt)
{
        int32 ret;

        ret = runtime·sys_umtx_op(addr, UMTX_OP_WAKE_PRIVATE, cnt, nil, nil);
        if(ret >= 0)
                return;

        runtime·printf("umtx_wake addr=%p ret=%d\n", addr, ret);
        *(int32*)0x1006 = 0x1006;
}

void runtime·thr_start(void*);

void
runtime·newosproc(M *mp, void *stk)
{
        ThrParam param;
        Sigset oset;

        if(0){
                runtime·printf("newosproc stk=%p m=%p g=%p id=%d/%d ostk=%p\n",
                        stk, mp, mp->g0, mp->id, (int32)mp->tls[0], &mp);
        }

        runtime·sigprocmask(&sigset_all, &oset);
        runtime·memclr((byte*)&param, sizeof param);

        param.start_func = runtime·thr_start;
        param.arg = (byte*)mp;
        
        // 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.stack_base = (void*)mp->g0->stackbase;
        param.stack_size = (byte*)stk - (byte*)mp->g0->stackbase;

        param.child_tid = (intptr*)&mp->procid;
        param.parent_tid = nil;
        param.tls_base = (void*)&mp->tls[0];
        param.tls_size = sizeof mp->tls;

        mp->tls[0] = mp->id;    // so 386 asm can find it

        runtime·thr_new(&param, sizeof param);
        runtime·sigprocmask(&oset, nil);
}

void
runtime·osinit(void)
{
        runtime·ncpu = getncpu();
}

void
runtime·get_random_data(byte **rnd, int32 *rnd_len)
{
        #pragma dataflag NOPTR
        static byte urandom_data[HashRandomBytes];
        int32 fd;
        fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
        if(runtime·read(fd, urandom_data, HashRandomBytes) == HashRandomBytes) {
                *rnd = urandom_data;
                *rnd_len = HashRandomBytes;
        } else {
                *rnd = nil;
                *rnd_len = 0;
        }
        runtime·close(fd);
}

void
runtime·goenvs(void)
{
        runtime·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.
void
runtime·mpreinit(M *mp)
{
        mp->gsignal = runtime·malg(32*1024);
}

// Called to initialize a new m (including the bootstrap m).
// Called on the new thread, can not allocate memory.
void
runtime·minit(void)
{
        // Initialize signal handling
        runtime·signalstack((byte*)m->gsignal->stackguard - StackGuard, 32*1024);
        runtime·sigprocmask(&sigset_none, nil);
}

// Called from dropm to undo the effect of an minit.
void
runtime·unminit(void)
{
        runtime·signalstack(nil, 0);
}

void
runtime·sigpanic(void)
{
        if(!runtime·canpanic(g))
                runtime·throw("unexpected signal during runtime execution");

        switch(g->sig) {
        case SIGBUS:
                if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000 || g->paniconfault) {
                        if(g->sigpc == 0)
                                runtime·panicstring("call of nil func value");
                        runtime·panicstring("invalid memory address or nil pointer dereference");
                }
                runtime·printf("unexpected fault address %p\n", g->sigcode1);
                runtime·throw("fault");
        case SIGSEGV:
                if((g->sigcode0 == 0 || g->sigcode0 == SEGV_MAPERR || g->sigcode0 == SEGV_ACCERR) && g->sigcode1 < 0x1000 || g->paniconfault) {
                        if(g->sigpc == 0)
                                runtime·panicstring("call of nil func value");
                        runtime·panicstring("invalid memory address or nil pointer dereference");
                }
                runtime·printf("unexpected fault address %p\n", g->sigcode1);
                runtime·throw("fault");
        case SIGFPE:
                switch(g->sigcode0) {
                case FPE_INTDIV:
                        runtime·panicstring("integer divide by zero");
                case FPE_INTOVF:
                        runtime·panicstring("integer overflow");
                }
                runtime·panicstring("floating point error");
        }
        runtime·panicstring(runtime·sigtab[g->sig].name);
}

uintptr
runtime·memlimit(void)
{
        Rlimit rl;
        extern byte text[], 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 = end - 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;
}

extern void runtime·sigtramp(void);

typedef struct sigaction {
        union {
                void    (*__sa_handler)(int32);
                void    (*__sa_sigaction)(int32, Siginfo*, void *);
        } __sigaction_u;                /* signal handler */
        int32   sa_flags;               /* see signal options below */
        Sigset  sa_mask;                /* signal mask to apply */
} Sigaction;

void
runtime·setsig(int32 i, GoSighandler *fn, bool restart)
{
        Sigaction sa;

        runtime·memclr((byte*)&sa, sizeof sa);
        sa.sa_flags = SA_SIGINFO|SA_ONSTACK;
        if(restart)
                sa.sa_flags |= SA_RESTART;
        sa.sa_mask.__bits[0] = ~(uint32)0;
        sa.sa_mask.__bits[1] = ~(uint32)0;
        sa.sa_mask.__bits[2] = ~(uint32)0;
        sa.sa_mask.__bits[3] = ~(uint32)0;
        if(fn == runtime·sighandler)
                fn = (void*)runtime·sigtramp;
        sa.__sigaction_u.__sa_sigaction = (void*)fn;
        runtime·sigaction(i, &sa, nil);
}

GoSighandler*
runtime·getsig(int32 i)
{
        Sigaction sa;

        runtime·memclr((byte*)&sa, sizeof sa);
        runtime·sigaction(i, nil, &sa);
        if((void*)sa.__sigaction_u.__sa_sigaction == runtime·sigtramp)
                return runtime·sighandler;
        return (void*)sa.__sigaction_u.__sa_sigaction;
}

void
runtime·signalstack(byte *p, int32 n)
{
        StackT st;

        st.ss_sp = (void*)p;
        st.ss_size = n;
        st.ss_flags = 0;
        if(p == nil)
                st.ss_flags = SS_DISABLE;
        runtime·sigaltstack(&st, nil);
}

void
runtime·unblocksignals(void)
{
        runtime·sigprocmask(&sigset_none, nil);
}
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root/src/pkg/runtime/os_freebsd.c

DEFINITIONS
