1 // Copyright 2013 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime 6 7 import "unsafe" 8 9 type sigctxt struct { 10 info *siginfo 11 ctxt unsafe.Pointer 12 } 13 14 //go:nosplit 15 //go:nowritebarrierrec 16 func (c *sigctxt) regs() *regs32 { return &(*ucontext)(c.ctxt).uc_mcontext.ss } 17 18 func (c *sigctxt) eax() uint32 { return c.regs().eax } 19 func (c *sigctxt) ebx() uint32 { return c.regs().ebx } 20 func (c *sigctxt) ecx() uint32 { return c.regs().ecx } 21 func (c *sigctxt) edx() uint32 { return c.regs().edx } 22 func (c *sigctxt) edi() uint32 { return c.regs().edi } 23 func (c *sigctxt) esi() uint32 { return c.regs().esi } 24 func (c *sigctxt) ebp() uint32 { return c.regs().ebp } 25 func (c *sigctxt) esp() uint32 { return c.regs().esp } 26 27 //go:nosplit 28 //go:nowritebarrierrec 29 func (c *sigctxt) eip() uint32 { return c.regs().eip } 30 31 func (c *sigctxt) eflags() uint32 { return c.regs().eflags } 32 func (c *sigctxt) cs() uint32 { return c.regs().cs } 33 func (c *sigctxt) fs() uint32 { return c.regs().fs } 34 func (c *sigctxt) gs() uint32 { return c.regs().gs } 35 func (c *sigctxt) sigcode() uint32 { return uint32(c.info.si_code) } 36 func (c *sigctxt) sigaddr() uint32 { return c.info.si_addr } 37 38 func (c *sigctxt) set_eip(x uint32) { c.regs().eip = x } 39 func (c *sigctxt) set_esp(x uint32) { c.regs().esp = x } 40 func (c *sigctxt) set_sigcode(x uint32) { c.info.si_code = int32(x) } 41 func (c *sigctxt) set_sigaddr(x uint32) { c.info.si_addr = x } 42 43 func (c *sigctxt) fixsigcode(sig uint32) { 44 switch sig { 45 case _SIGTRAP: 46 // OS X sets c.sigcode() == TRAP_BRKPT unconditionally for all SIGTRAPs, 47 // leaving no way to distinguish a breakpoint-induced SIGTRAP 48 // from an asynchronous signal SIGTRAP. 49 // They all look breakpoint-induced by default. 50 // Try looking at the code to see if it's a breakpoint. 51 // The assumption is that we're very unlikely to get an 52 // asynchronous SIGTRAP at just the moment that the 53 // PC started to point at unmapped memory. 54 pc := uintptr(c.eip()) 55 // OS X will leave the pc just after the INT 3 instruction. 56 // INT 3 is usually 1 byte, but there is a 2-byte form. 57 code := (*[2]byte)(unsafe.Pointer(pc - 2)) 58 if code[1] != 0xCC && (code[0] != 0xCD || code[1] != 3) { 59 // SIGTRAP on something other than INT 3. 60 c.set_sigcode(_SI_USER) 61 } 62 } 63 } 64
