github.com/euank/go@v0.0.0-20160829210321-495514729181/src/runtime/signal_386.go (about) 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 // +build darwin dragonfly freebsd linux nacl netbsd openbsd 6 7 package runtime 8 9 import ( 10 "runtime/internal/sys" 11 "unsafe" 12 ) 13 14 func dumpregs(c *sigctxt) { 15 print("eax ", hex(c.eax()), "\n") 16 print("ebx ", hex(c.ebx()), "\n") 17 print("ecx ", hex(c.ecx()), "\n") 18 print("edx ", hex(c.edx()), "\n") 19 print("edi ", hex(c.edi()), "\n") 20 print("esi ", hex(c.esi()), "\n") 21 print("ebp ", hex(c.ebp()), "\n") 22 print("esp ", hex(c.esp()), "\n") 23 print("eip ", hex(c.eip()), "\n") 24 print("eflags ", hex(c.eflags()), "\n") 25 print("cs ", hex(c.cs()), "\n") 26 print("fs ", hex(c.fs()), "\n") 27 print("gs ", hex(c.gs()), "\n") 28 } 29 30 var crashing int32 31 32 // May run during STW, so write barriers are not allowed. 33 // 34 //go:nowritebarrierrec 35 func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) { 36 _g_ := getg() 37 c := &sigctxt{info, ctxt} 38 39 if sig == _SIGPROF { 40 sigprof(uintptr(c.eip()), uintptr(c.esp()), 0, gp, _g_.m) 41 return 42 } 43 44 flags := int32(_SigThrow) 45 if sig < uint32(len(sigtable)) { 46 flags = sigtable[sig].flags 47 } 48 if c.sigcode() != _SI_USER && flags&_SigPanic != 0 { 49 // Make it look like a call to the signal func. 50 // Have to pass arguments out of band since 51 // augmenting the stack frame would break 52 // the unwinding code. 53 gp.sig = sig 54 gp.sigcode0 = uintptr(c.sigcode()) 55 gp.sigcode1 = uintptr(c.sigaddr()) 56 gp.sigpc = uintptr(c.eip()) 57 58 if GOOS == "darwin" { 59 // Work around Leopard bug that doesn't set FPE_INTDIV. 60 // Look at instruction to see if it is a divide. 61 // Not necessary in Snow Leopard (si_code will be != 0). 62 if sig == _SIGFPE && gp.sigcode0 == 0 { 63 pc := (*[4]byte)(unsafe.Pointer(gp.sigpc)) 64 i := 0 65 if pc[i] == 0x66 { // 16-bit instruction prefix 66 i++ 67 } 68 if pc[i] == 0xF6 || pc[i] == 0xF7 { 69 gp.sigcode0 = _FPE_INTDIV 70 } 71 } 72 } 73 74 pc := uintptr(c.eip()) 75 sp := uintptr(c.esp()) 76 77 // If we don't recognize the PC as code 78 // but we do recognize the top pointer on the stack as code, 79 // then assume this was a call to non-code and treat like 80 // pc == 0, to make unwinding show the context. 81 if pc != 0 && findfunc(pc) == nil && findfunc(*(*uintptr)(unsafe.Pointer(sp))) != nil { 82 pc = 0 83 } 84 85 // Only push runtime.sigpanic if pc != 0. 86 // If pc == 0, probably panicked because of a 87 // call to a nil func. Not pushing that onto sp will 88 // make the trace look like a call to runtime.sigpanic instead. 89 // (Otherwise the trace will end at runtime.sigpanic and we 90 // won't get to see who faulted.) 91 if pc != 0 { 92 if sys.RegSize > sys.PtrSize { 93 sp -= sys.PtrSize 94 *(*uintptr)(unsafe.Pointer(sp)) = 0 95 } 96 sp -= sys.PtrSize 97 *(*uintptr)(unsafe.Pointer(sp)) = pc 98 c.set_esp(uint32(sp)) 99 } 100 c.set_eip(uint32(funcPC(sigpanic))) 101 return 102 } 103 104 if c.sigcode() == _SI_USER || flags&_SigNotify != 0 { 105 if sigsend(sig) { 106 return 107 } 108 } 109 110 if c.sigcode() == _SI_USER && signal_ignored(sig) { 111 return 112 } 113 114 if flags&_SigKill != 0 { 115 dieFromSignal(int32(sig)) 116 } 117 118 if flags&_SigThrow == 0 { 119 return 120 } 121 122 _g_.m.throwing = 1 123 _g_.m.caughtsig.set(gp) 124 125 if crashing == 0 { 126 startpanic() 127 } 128 129 if sig < uint32(len(sigtable)) { 130 print(sigtable[sig].name, "\n") 131 } else { 132 print("Signal ", sig, "\n") 133 } 134 135 print("PC=", hex(c.eip()), " m=", _g_.m.id, "\n") 136 if _g_.m.lockedg != nil && _g_.m.ncgo > 0 && gp == _g_.m.g0 { 137 print("signal arrived during cgo execution\n") 138 gp = _g_.m.lockedg 139 } 140 print("\n") 141 142 level, _, docrash := gotraceback() 143 if level > 0 { 144 goroutineheader(gp) 145 tracebacktrap(uintptr(c.eip()), uintptr(c.esp()), 0, gp) 146 if crashing > 0 && gp != _g_.m.curg && _g_.m.curg != nil && readgstatus(_g_.m.curg)&^_Gscan == _Grunning { 147 // tracebackothers on original m skipped this one; trace it now. 148 goroutineheader(_g_.m.curg) 149 traceback(^uintptr(0), ^uintptr(0), 0, gp) 150 } else if crashing == 0 { 151 tracebackothers(gp) 152 print("\n") 153 } 154 dumpregs(c) 155 } 156 157 if docrash { 158 crashing++ 159 if crashing < sched.mcount { 160 // There are other m's that need to dump their stacks. 161 // Relay SIGQUIT to the next m by sending it to the current process. 162 // All m's that have already received SIGQUIT have signal masks blocking 163 // receipt of any signals, so the SIGQUIT will go to an m that hasn't seen it yet. 164 // When the last m receives the SIGQUIT, it will fall through to the call to 165 // crash below. Just in case the relaying gets botched, each m involved in 166 // the relay sleeps for 5 seconds and then does the crash/exit itself. 167 // In expected operation, the last m has received the SIGQUIT and run 168 // crash/exit and the process is gone, all long before any of the 169 // 5-second sleeps have finished. 170 print("\n-----\n\n") 171 raiseproc(_SIGQUIT) 172 usleep(5 * 1000 * 1000) 173 } 174 crash() 175 } 176 177 exit(2) 178 }