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exceptions.cc
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/* exceptions.cc
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#define CYGTLS_HANDLE
#include "winsup.h"
#include "miscfuncs.h"
#include <imagehlp.h>
#include <stdlib.h>
#include <stdarg.h>
#include <syslog.h>
#include <wchar.h>
#include "cygtls.h"
#include "pinfo.h"
#include "sigproc.h"
#include "shared_info.h"
#include "perprocess.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "child_info.h"
#include "ntdll.h"
#include "exception.h"
#include "posix_timer.h"
#include "gcc_seh.h"
#include "cygwin/exit_process.h"
/* Definitions for code simplification */
#ifdef __x86_64__
# define _GR(reg) R ## reg
# define _AFMT "%011X"
# define _ADDR DWORD64
#else
# define _GR(reg) E ## reg
# define _AFMT "%08x"
# define _ADDR DWORD
#endif
#define CALL_HANDLER_RETRY_OUTER 10
#define CALL_HANDLER_RETRY_INNER 10
#define DUMPSTACK_FRAME_LIMIT 32
PWCHAR debugger_command;
extern uint8_t _sigbe;
extern uint8_t _sigdelayed_end;
static BOOL WINAPI ctrl_c_handler (DWORD);
static const struct
{
NTSTATUS code;
const char *name;
} status_info[] =
{
#define X(s) s, #s
{ X (STATUS_ABANDONED_WAIT_0) },
{ X (STATUS_ACCESS_VIOLATION) },
{ X (STATUS_ARRAY_BOUNDS_EXCEEDED) },
{ X (STATUS_BREAKPOINT) },
{ X (STATUS_CONTROL_C_EXIT) },
{ X (STATUS_DATATYPE_MISALIGNMENT) },
{ X (STATUS_FLOAT_DENORMAL_OPERAND) },
{ X (STATUS_FLOAT_DIVIDE_BY_ZERO) },
{ X (STATUS_FLOAT_INEXACT_RESULT) },
{ X (STATUS_FLOAT_INVALID_OPERATION) },
{ X (STATUS_FLOAT_OVERFLOW) },
{ X (STATUS_FLOAT_STACK_CHECK) },
{ X (STATUS_FLOAT_UNDERFLOW) },
{ X (STATUS_GUARD_PAGE_VIOLATION) },
{ X (STATUS_ILLEGAL_INSTRUCTION) },
{ X (STATUS_INTEGER_DIVIDE_BY_ZERO) },
{ X (STATUS_INTEGER_OVERFLOW) },
{ X (STATUS_INVALID_DISPOSITION) },
{ X (STATUS_IN_PAGE_ERROR) },
{ X (STATUS_NONCONTINUABLE_EXCEPTION) },
{ X (STATUS_NO_MEMORY) },
{ X (STATUS_PENDING) },
{ X (STATUS_PRIVILEGED_INSTRUCTION) },
{ X (STATUS_SINGLE_STEP) },
{ X (STATUS_STACK_OVERFLOW) },
{ X (STATUS_TIMEOUT) },
{ X (STATUS_USER_APC) },
{ X (STATUS_WAIT_0) },
{ 0, 0 }
#undef X
};
/* Initialization code. */
void
init_console_handler (bool install_handler)
{
BOOL res;
SetConsoleCtrlHandler (ctrl_c_handler, FALSE);
SetConsoleCtrlHandler (NULL, FALSE);
if (install_handler)
res = SetConsoleCtrlHandler (ctrl_c_handler, TRUE);
else
res = SetConsoleCtrlHandler (NULL, TRUE);
if (!res)
system_printf ("SetConsoleCtrlHandler failed, %E");
}
extern "C" void
error_start_init (const char *buf)
{
if (!buf || !*buf)
return;
if (!debugger_command &&
!(debugger_command = (PWCHAR) malloc ((2 * NT_MAX_PATH + 20)
* sizeof (WCHAR))))
return;
PWCHAR cp = debugger_command
+ sys_mbstowcs (debugger_command, NT_MAX_PATH, buf) - 1;
cp = wcpcpy (cp, L" \"");
wcpcpy (cp, global_progname);
for (PWCHAR p = wcschr (cp, L'\\'); p; p = wcschr (p, L'\\'))
*p = L'/';
wcscat (cp, L"\"");
}
void
cygwin_exception::open_stackdumpfile ()
{
/* If we have no executable name, or if the CWD handle is NULL,
which means, the CWD is a virtual path, don't even try to open
a stackdump file. */
if (myself->progname[0] && cygheap->cwd.get_handle ())
{
const WCHAR *p;
/* write to progname.stackdump if possible */
if (!myself->progname[0])
p = L"unknown";
else if ((p = wcsrchr (myself->progname, L'\\')))
p++;
else
p = myself->progname;
WCHAR corefile[wcslen (p) + sizeof (".stackdump")];
wcpcpy (wcpcpy(corefile, p), L".stackdump");
UNICODE_STRING ucore;
OBJECT_ATTRIBUTES attr;
/* Create the UNICODE variation of <progname>.stackdump. */
RtlInitUnicodeString (&ucore, corefile);
/* Create an object attribute which refers to <progname>.stackdump
in Cygwin's cwd. Stick to caseinsensitivity. */
InitializeObjectAttributes (&attr, &ucore, OBJ_CASE_INSENSITIVE,
cygheap->cwd.get_handle (), NULL);
IO_STATUS_BLOCK io;
NTSTATUS status;
/* Try to open it to dump the stack in it. */
status = NtCreateFile (&h, GENERIC_WRITE | SYNCHRONIZE, &attr, &io,
NULL, FILE_ATTRIBUTE_NORMAL, 0, FILE_OVERWRITE_IF,
FILE_SYNCHRONOUS_IO_NONALERT
| FILE_OPEN_FOR_BACKUP_INTENT, NULL, 0);
if (NT_SUCCESS (status))
{
if (!myself->cygstarted)
system_printf ("Dumping stack trace to %S", &ucore);
else
debug_printf ("Dumping stack trace to %S", &ucore);
SetStdHandle (STD_ERROR_HANDLE, h);
}
}
}
/* Utilities for dumping the stack, etc. */
void
cygwin_exception::dump_exception ()
{
const char *exception_name = NULL;
for (int i = 0; status_info[i].name; i++)
{
if (status_info[i].code == (NTSTATUS) e->ExceptionCode)
{
exception_name = status_info[i].name;
break;
}
}
#ifdef __x86_64__
if (exception_name)
small_printf ("Exception: %s at rip=%011X\r\n", exception_name, ctx->Rip);
else
small_printf ("Signal %d at rip=%011X\r\n", e->ExceptionCode, ctx->Rip);
small_printf ("rax=%016X rbx=%016X rcx=%016X\r\n",
ctx->Rax, ctx->Rbx, ctx->Rcx);
small_printf ("rdx=%016X rsi=%016X rdi=%016X\r\n",
ctx->Rdx, ctx->Rsi, ctx->Rdi);
small_printf ("r8 =%016X r9 =%016X r10=%016X\r\n",
ctx->R8, ctx->R9, ctx->R10);
small_printf ("r11=%016X r12=%016X r13=%016X\r\n",
ctx->R11, ctx->R12, ctx->R13);
small_printf ("r14=%016X r15=%016X\r\n", ctx->R14, ctx->R15);
small_printf ("rbp=%016X rsp=%016X\r\n", ctx->Rbp, ctx->Rsp);
small_printf ("program=%W, pid %u, thread %s\r\n",
myself->progname, myself->pid, mythreadname ());
#else
if (exception_name)
small_printf ("Exception: %s at eip=%08x\r\n", exception_name, ctx->Eip);
else
small_printf ("Signal %d at eip=%08x\r\n", e->ExceptionCode, ctx->Eip);
small_printf ("eax=%08x ebx=%08x ecx=%08x edx=%08x esi=%08x edi=%08x\r\n",
ctx->Eax, ctx->Ebx, ctx->Ecx, ctx->Edx, ctx->Esi, ctx->Edi);
small_printf ("ebp=%08x esp=%08x program=%W, pid %u, thread %s\r\n",
ctx->Ebp, ctx->Esp, myself->progname, myself->pid,
mythreadname ());
#endif
small_printf ("cs=%04x ds=%04x es=%04x fs=%04x gs=%04x ss=%04x\r\n",
ctx->SegCs, ctx->SegDs, ctx->SegEs, ctx->SegFs,
ctx->SegGs, ctx->SegSs);
}
/* A class for manipulating the stack. */
class stack_info
{
int walk (); /* Uses the "old" method */
char *next_offset () {return *((char **) sf.AddrFrame.Offset);}
bool needargs;
PUINT_PTR dummy_frame;
#ifdef __x86_64__
CONTEXT c;
UNWIND_HISTORY_TABLE hist;
__tlsstack_t *sigstackptr;
#endif
public:
STACKFRAME sf; /* For storing the stack information */
void init (PUINT_PTR, bool, PCONTEXT); /* Called the first time that stack info is needed */
/* Postfix ++ iterates over the stack, returning zero when nothing is left. */
int operator ++(int) { return walk (); }
};
/* The number of parameters used in STACKFRAME */
#define NPARAMS (sizeof (thestack.sf.Params) / sizeof (thestack.sf.Params[0]))
/* This is the main stack frame info for this process. */
static NO_COPY stack_info thestack;
/* Initialize everything needed to start iterating. */
void
stack_info::init (PUINT_PTR framep, bool wantargs, PCONTEXT ctx)
{
#ifdef __x86_64__
memset (&hist, 0, sizeof hist);
if (ctx)
memcpy (&c, ctx, sizeof c);
else
{
memset (&c, 0, sizeof c);
c.ContextFlags = CONTEXT_ALL;
}
sigstackptr = _my_tls.stackptr;
#endif
memset (&sf, 0, sizeof (sf));
if (ctx)
sf.AddrFrame.Offset = (UINT_PTR) framep;
else
{
dummy_frame = framep;
sf.AddrFrame.Offset = (UINT_PTR) &dummy_frame;
}
if (framep)
sf.AddrReturn.Offset = framep[1];
sf.AddrFrame.Mode = AddrModeFlat;
needargs = wantargs;
}
extern "C" void _cygwin_exit_return ();
#ifdef __x86_64__
static inline void
__unwind_single_frame (PCONTEXT ctx)
{
PRUNTIME_FUNCTION f;
ULONG64 imagebase;
UNWIND_HISTORY_TABLE hist = {0};
DWORD64 establisher;
PVOID hdl;
f = RtlLookupFunctionEntry (ctx->Rip, &imagebase, &hist);
if (f)
RtlVirtualUnwind (0, imagebase, ctx->Rip, f, ctx, &hdl, &establisher,
NULL);
else
{
ctx->Rip = *(ULONG_PTR *) ctx->Rsp;
ctx->Rsp += 8;
}
}
#else
#define __unwind_single_frame(ctx)
#endif
/* Walk the stack.
On 32 bit we're doing this by looking at successive stored 'ebp' frames.
This is not foolproof. */
int
stack_info::walk ()
{
#ifdef __x86_64__
if (!c.Rip)
return 0;
sf.AddrPC.Offset = c.Rip;
sf.AddrStack.Offset = c.Rsp;
sf.AddrFrame.Offset = c.Rbp;
if ((c.Rip >= (DWORD64)&_sigbe) && (c.Rip < (DWORD64)&_sigdelayed_end))
{
/* _sigbe and sigdelayed don't have SEH unwinding data, so virtually
unwind the tls sigstack */
c.Rip = sigstackptr[-1];
sigstackptr--;
return 1;
}
__unwind_single_frame (&c);
if (needargs && c.Rip)
{
PULONG_PTR p = (PULONG_PTR) c.Rsp;
for (unsigned i = 0; i < NPARAMS; ++i)
sf.Params[i] = p[i + 1];
}
return 1;
#else
char **framep;
if ((void (*) ()) sf.AddrPC.Offset == _cygwin_exit_return)
return 0; /* stack frames are exhausted */
if (((framep = (char **) next_offset ()) == NULL)
|| (framep >= (char **) cygwin_hmodule))
return 0;
sf.AddrFrame.Offset = (_ADDR) framep;
sf.AddrPC.Offset = sf.AddrReturn.Offset;
/* The return address always follows the stack pointer */
sf.AddrReturn.Offset = (_ADDR) *++framep;
if (needargs)
{
unsigned nparams = NPARAMS;
/* The arguments follow the return address */
sf.Params[0] = (_ADDR) *++framep;
for (unsigned i = 1; i < nparams; i++)
sf.Params[i] = (_ADDR) *++framep;
}
return 1;
#endif
}
void
cygwin_exception::dumpstack ()
{
static bool already_dumped;
__try
{
if (already_dumped || cygheap->rlim_core == 0Ul)
return;
already_dumped = true;
open_stackdumpfile ();
if (e)
dump_exception ();
int i;
thestack.init (framep, 1, ctx); /* Initialize from the input CONTEXT */
#ifdef __x86_64__
small_printf ("Stack trace:\r\nFrame Function Args\r\n");
#else
small_printf ("Stack trace:\r\nFrame Function Args\r\n");
#endif
for (i = 0; i < DUMPSTACK_FRAME_LIMIT && thestack++; i++)
{
small_printf (_AFMT " " _AFMT, thestack.sf.AddrFrame.Offset,
thestack.sf.AddrPC.Offset);
for (unsigned j = 0; j < NPARAMS; j++)
small_printf ("%s" _AFMT, j == 0 ? " (" : ", ",
thestack.sf.Params[j]);
small_printf (")\r\n");
}
small_printf ("End of stack trace%s\n",
i == DUMPSTACK_FRAME_LIMIT ?
" (more stack frames may be present)" : "");
if (h)
NtClose (h);
}
__except (NO_ERROR) {}
__endtry
}
bool
_cygtls::inside_kernel (CONTEXT *cx)
{
int res;
MEMORY_BASIC_INFORMATION m;
if (!isinitialized ())
return true;
memset (&m, 0, sizeof m);
if (!VirtualQuery ((LPCVOID) cx->_GR(ip), &m, sizeof m))
sigproc_printf ("couldn't get memory info, pc %p, %E", cx->_GR(ip));
size_t size = (windows_system_directory_length + 6) * sizeof (WCHAR);
PWCHAR checkdir = (PWCHAR) alloca (size);
memset (checkdir, 0, size);
# define h ((HMODULE) m.AllocationBase)
if (!h || m.State != MEM_COMMIT) /* Be defensive */
res = true;
else if (h == hntdll)
res = true; /* Calling GetModuleFilename on ntdll.dll
can hang */
else if (h == user_data->hmodule)
res = false;
else if (!GetModuleFileNameW (h, checkdir,
windows_system_directory_length + 6))
res = false;
else
{
/* Skip potential long path prefix. */
if (!wcsncmp (checkdir, L"\\\\?\\", 4))
checkdir += 4;
res = wcsncasecmp (windows_system_directory, checkdir,
windows_system_directory_length) == 0;
#ifdef __i386__
if (!res && system_wow64_directory_length)
res = wcsncasecmp (system_wow64_directory, checkdir,
system_wow64_directory_length) == 0;
#endif
}
sigproc_printf ("pc %p, h %p, inside_kernel %d", cx->_GR(ip), h, res);
# undef h
return res;
}
/* Temporary (?) function for external callers to get a stack dump */
extern "C" void
cygwin_stackdump ()
{
CONTEXT c;
c.ContextFlags = CONTEXT_FULL;
RtlCaptureContext (&c);
cygwin_exception exc ((PUINT_PTR) c._GR(bp), &c);
exc.dumpstack ();
}
extern "C" int
try_to_debug ()
{
if (!debugger_command)
return 0;
debug_printf ("debugger_command '%W'", debugger_command);
if (being_debugged ())
{
extern void break_here ();
break_here ();
return 0;
}
PWCHAR dbg_end = wcschr (debugger_command, L'\0');
__small_swprintf (dbg_end, L" %u", GetCurrentProcessId ());
LONG prio = GetThreadPriority (GetCurrentThread ());
SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_HIGHEST);
PROCESS_INFORMATION pi = {NULL, 0, 0, 0};
STARTUPINFOW si = {0, NULL, NULL, NULL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
NULL, NULL, NULL, NULL};
si.lpReserved = NULL;
si.lpDesktop = NULL;
si.dwFlags = 0;
si.cb = sizeof (si);
/* FIXME: need to know handles of all running threads to
suspend_all_threads_except (current_thread_id);
*/
/* If the tty mutex is owned, we will fail to start any cygwin app
until the trapped app exits. However, this will only release any
the mutex if it is owned by this thread so that may be problematic. */
lock_ttys::release ();
/* prevent recursive exception handling */
PWCHAR rawenv = GetEnvironmentStringsW () ;
for (PWCHAR p = rawenv; *p != L'\0'; p = wcschr (p, L'\0') + 1)
{
if (wcsncmp (p, L"MSYS=", wcslen (L"MSYS=")) == 0)
{
PWCHAR q = wcsstr (p, L"error_start") ;
/* replace 'error_start=...' with '_rror_start=...' */
if (q)
{
*q = L'_' ;
SetEnvironmentVariableW (L"MSYS", p + wcslen (L"MSYS=")) ;
}
break;
}
}
FreeEnvironmentStringsW (rawenv);
console_printf ("*** starting debugger for pid %u, tid %u\n",
cygwin_pid (GetCurrentProcessId ()), GetCurrentThreadId ());
BOOL dbg;
dbg = CreateProcessW (NULL,
debugger_command,
NULL,
NULL,
FALSE,
CREATE_NEW_CONSOLE | CREATE_NEW_PROCESS_GROUP,
NULL,
NULL,
&si,
&pi);
/* We want to stop here and wait until the error_start process attaches. But
we can't wait here for the error_start process to exit, as if it's a
debugger, it might want to continue this thread. So we busy wait until a
debugger attaches, which stops this process, after which it can decide if
we continue or not. */
*dbg_end = L'\0';
if (!dbg)
system_printf ("Failed to start debugger, %E");
else
{
SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_IDLE);
while (!being_debugged ())
Sleep (1);
Sleep (2000);
}
console_printf ("*** continuing pid %u from debugger call (%d)\n",
cygwin_pid (GetCurrentProcessId ()), dbg);
SetThreadPriority (GetCurrentThread (), prio);
return dbg;
}
#ifdef __x86_64__
/* Don't unwind the stack on x86_64. It's not necessary to do that from the
exception handler. */
#define rtl_unwind(el,er)
#else
static void __reg3 rtl_unwind (exception_list *, PEXCEPTION_RECORD)
__attribute__ ((noinline, regparm (3)));
void __reg3
rtl_unwind (exception_list *frame, PEXCEPTION_RECORD e)
{
__asm__ ("\n\
pushl %%ebx \n\
pushl %%edi \n\
pushl %%esi \n\
pushl $0 \n\
pushl %1 \n\
pushl $1f \n\
pushl %0 \n\
call _RtlUnwind@16 \n\
1: \n\
popl %%esi \n\
popl %%edi \n\
popl %%ebx \n\
": : "r" (frame), "r" (e));
}
#endif /* __x86_64 */
#ifdef __x86_64__
/* myfault exception handler. */
EXCEPTION_DISPOSITION
exception::myfault (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *in,
PDISPATCHER_CONTEXT dispatch)
{
PSCOPE_TABLE table = (PSCOPE_TABLE) dispatch->HandlerData;
RtlUnwindEx (frame,
(char *) dispatch->ImageBase + table->ScopeRecord[0].JumpTarget,
e, 0, in, dispatch->HistoryTable);
/* NOTREACHED, make gcc happy. */
return ExceptionContinueSearch;
}
/* If another exception occurs while running a signal handler on an alternate
signal stack, the normal SEH handlers are skipped, because the OS exception
handling considers the current (alternate) stack "broken". However, it
still calls vectored exception handlers.
TODO: What we do here is to handle only __try/__except blocks in Cygwin.
"Normal" exceptions will simply exit the process. Still, better
than nothing... */
LONG WINAPI
myfault_altstack_handler (EXCEPTION_POINTERS *exc)
{
_cygtls& me = _my_tls;
if (me.andreas)
{
CONTEXT *c = exc->ContextRecord;
/* Unwind the stack manually and call RtlRestoreContext. This
is necessary because RtlUnwindEx checks the stack for validity,
which, as outlined above, fails for the alternate stack. */
while (c->Rsp < me.andreas->frame)
__unwind_single_frame (c);
c->Rip = me.andreas->ret;
RtlRestoreContext (c, NULL);
}
return EXCEPTION_CONTINUE_SEARCH;
}
#endif
/* Main exception handler. */
EXCEPTION_DISPOSITION
exception::handle (EXCEPTION_RECORD *e, exception_list *frame, CONTEXT *in,
PDISPATCHER_CONTEXT dispatch)
{
static int NO_COPY debugging = 0;
_cygtls& me = _my_tls;
#ifdef __i386__
if (me.andreas)
me.andreas->leave (); /* Return from a "san" caught fault */
#endif
if (debugging && ++debugging < 500000)
{
SetThreadPriority (hMainThread, THREAD_PRIORITY_NORMAL);
return ExceptionContinueExecution;
}
/* If we're exiting, tell Windows to keep looking for an
exception handler. */
if (exit_state || e->ExceptionFlags)
return ExceptionContinueSearch;
siginfo_t si = {};
si.si_code = SI_KERNEL;
/* Coerce win32 value to posix value. */
switch (e->ExceptionCode)
{
case STATUS_FLOAT_DIVIDE_BY_ZERO:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTDIV;
break;
case STATUS_FLOAT_DENORMAL_OPERAND:
case STATUS_FLOAT_INVALID_OPERATION:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTINV;
break;
case STATUS_FLOAT_STACK_CHECK:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTSUB;
break;
case STATUS_FLOAT_INEXACT_RESULT:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTRES;
break;
case STATUS_FLOAT_OVERFLOW:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTOVF;
break;
case STATUS_FLOAT_UNDERFLOW:
si.si_signo = SIGFPE;
si.si_code = FPE_FLTUND;
break;
case STATUS_INTEGER_DIVIDE_BY_ZERO:
si.si_signo = SIGFPE;
si.si_code = FPE_INTDIV;
break;
case STATUS_INTEGER_OVERFLOW:
si.si_signo = SIGFPE;
si.si_code = FPE_INTOVF;
break;
case STATUS_ILLEGAL_INSTRUCTION:
si.si_signo = SIGILL;
si.si_code = ILL_ILLOPC;
break;
case STATUS_PRIVILEGED_INSTRUCTION:
si.si_signo = SIGILL;
si.si_code = ILL_PRVOPC;
break;
case STATUS_NONCONTINUABLE_EXCEPTION:
si.si_signo = SIGILL;
si.si_code = ILL_ILLADR;
break;
case STATUS_TIMEOUT:
si.si_signo = SIGALRM;
break;
case STATUS_GUARD_PAGE_VIOLATION:
si.si_signo = SIGBUS;
si.si_code = BUS_OBJERR;
break;
case STATUS_DATATYPE_MISALIGNMENT:
si.si_signo = SIGBUS;
si.si_code = BUS_ADRALN;
break;
case STATUS_ACCESS_VIOLATION:
switch (mmap_is_attached_or_noreserve ((void *)e->ExceptionInformation[1],
1))
{
case MMAP_NORESERVE_COMMITED:
return ExceptionContinueExecution;
case MMAP_RAISE_SIGBUS: /* MAP_NORESERVE page, commit failed, or
access to mmap page beyond EOF. */
si.si_signo = SIGBUS;
si.si_code = BUS_OBJERR;
break;
default:
MEMORY_BASIC_INFORMATION m;
VirtualQuery ((PVOID) e->ExceptionInformation[1], &m, sizeof m);
si.si_signo = SIGSEGV;
si.si_code = m.State == MEM_FREE ? SEGV_MAPERR : SEGV_ACCERR;
break;
}
break;
case STATUS_STACK_OVERFLOW:
/* If we encounter a stack overflow, and if the thread has no alternate
stack, don't even try to call a signal handler. This is in line with
Linux behaviour and also makes a lot of sense on Windows. */
if (me.altstack.ss_flags)
global_sigs[SIGSEGV].sa_handler = SIG_DFL;
fallthrough;
case STATUS_ARRAY_BOUNDS_EXCEEDED:
case STATUS_IN_PAGE_ERROR:
case STATUS_NO_MEMORY:
case STATUS_INVALID_DISPOSITION:
si.si_signo = SIGSEGV;
si.si_code = SEGV_MAPERR;
break;
case STATUS_CONTROL_C_EXIT:
si.si_signo = SIGINT;
break;
case STATUS_INVALID_HANDLE:
/* CloseHandle will throw this exception if it is given an
invalid handle. We don't care about the exception; we just
want CloseHandle to return an error. This can be revisited
if gcc ever supports Windows style structured exception
handling. */
return ExceptionContinueExecution;
#ifdef __x86_64__
case STATUS_GCC_THROW:
case STATUS_GCC_UNWIND:
case STATUS_GCC_FORCED:
/* According to a comment in the GCC function
_Unwind_RaiseException(), GCC expects us to continue all the
(continuable) GCC exceptions that reach us. */
return ExceptionContinueExecution;
#endif
default:
/* If we don't recognize the exception, we have to assume that
we are doing structured exception handling, and we let
something else handle it. */
return ExceptionContinueSearch;
}
debug_printf ("In cygwin_except_handler exception %y at %p sp %p",
e->ExceptionCode, in->_GR(ip), in->_GR(sp));
debug_printf ("In cygwin_except_handler signal %d at %p",
si.si_signo, in->_GR(ip));
#ifdef __x86_64__
PUINT_PTR framep = (PUINT_PTR) in->Rbp;
/* Sometimes, when a stack is screwed up, Rbp tends to be NULL. In that
case, base the stacktrace on Rsp. In most cases, it allows to generate
useful stack trace. */
if (!framep)
framep = (PUINT_PTR) in->Rsp;
#else
PUINT_PTR framep = (PUINT_PTR) in->_GR(sp);
for (PUINT_PTR bpend = (PUINT_PTR) __builtin_frame_address (0);
framep > bpend;
framep--)
if (*framep == in->SegCs && framep[-1] == in->_GR(ip))
{
framep -= 2;
break;
}
/* Temporarily replace windows top level SEH with our own handler.
We don't want any Windows magic kicking in. This top level frame
will be removed automatically after our exception handler returns. */
_except_list->handler = handle;
#endif
if (exit_state >= ES_SIGNAL_EXIT
&& (NTSTATUS) e->ExceptionCode != STATUS_CONTROL_C_EXIT)
api_fatal ("Exception during process exit");
else if (!try_to_debug ())
rtl_unwind (frame, e);
else
{
debugging = 1;
return ExceptionContinueExecution;
}
cygwin_exception exc (framep, in, e);
si.si_cyg = (void *) &exc;
/* POSIX requires that for SIGSEGV and SIGBUS, si_addr should be set to the
address of faulting memory reference. For SIGILL and SIGFPE these should
be the address of the faulting instruction. Other signals are apparently
undefined so we just set those to the faulting instruction too. */
si.si_addr = (si.si_signo == SIGSEGV || si.si_signo == SIGBUS)
? (void *) e->ExceptionInformation[1] : (void *) in->_GR(ip);
me.incyg++;
sig_send (NULL, si, &me); /* Signal myself */
if ((NTSTATUS) e->ExceptionCode == STATUS_STACK_OVERFLOW)
{
/* If we catched a stack overflow, and if the signal handler didn't exit
or longjmp, we're back here and about to continue, supposed to run the
offending instruction again. That works on Linux, but not on Windows.
In case of a stack overflow we're not immediately returning to the
system exception handler, but to NTDLL::__stkchk. __stkchk will then
terminate the applicaton. So what we do here is to signal our current
process again, but this time with SIG_DFL action. This creates a
stackdump and then exits through our own means. */
global_sigs[SIGSEGV].sa_handler = SIG_DFL;
sig_send (NULL, si, &me);
}
me.incyg--;
e->ExceptionFlags = 0;
return ExceptionContinueExecution;
}
/* Utilities to call a user supplied exception handler. */
#define SIG_NONMASKABLE (SIGTOMASK (SIGKILL) | SIGTOMASK (SIGSTOP))
/* Non-raceable sigsuspend
Note: This implementation is based on the Single UNIX Specification
man page. This indicates that sigsuspend always returns -1 and that
attempts to block unblockable signals will be silently ignored.
This is counter to what appears to be documented in some UNIX
man pages, e.g. Linux. */
int __stdcall
handle_sigsuspend (sigset_t tempmask)
{
sigset_t oldmask = _my_tls.sigmask; // Remember for restoration
set_signal_mask (_my_tls.sigmask, tempmask);
sigproc_printf ("oldmask %ly, newmask %ly", oldmask, tempmask);
pthread_testcancel ();
cygwait (NULL, cw_infinite, cw_cancel | cw_cancel_self | cw_sig_eintr);
set_sig_errno (EINTR); // Per POSIX
/* A signal dispatch function will have been added to our stack and will
be hit eventually. Set the old mask to be restored when the signal
handler returns and indicate its presence by modifying deltamask. */
_my_tls.deltamask |= SIG_NONMASKABLE;
_my_tls.oldmask = oldmask; // Will be restored by signal handler
return -1;
}
extern DWORD exec_exit; // Possible exit value for exec
extern "C" {
static void
sig_handle_tty_stop (int sig, siginfo_t *, void *)
{
/* Silently ignore attempts to suspend if there is no accommodating
cygwin parent to deal with this behavior. */
if (!myself->cygstarted)
myself->process_state &= ~PID_STOPPED;
else
{
_my_tls.incyg = 1;
myself->stopsig = sig;
myself->alert_parent (sig);
sigproc_printf ("process %d stopped by signal %d", myself->pid, sig);
/* FIXME! This does nothing to suspend anything other than the main
thread. */
/* Use special cygwait parameter to handle SIGCONT. _main_tls.sig will
be cleared under lock when SIGCONT is detected. */
pthread::suspend_all_except_self ();
DWORD res = cygwait (NULL, cw_infinite, cw_sig_cont);
pthread::resume_all ();
switch (res)
{
case WAIT_SIGNALED:
myself->stopsig = SIGCONT;
myself->alert_parent (SIGCONT);
break;
default:
api_fatal ("WaitSingleObject returned %d", res);
break;
}
_my_tls.incyg = 0;
}
}
} /* end extern "C" */
bool
_cygtls::interrupt_now (CONTEXT *cx, siginfo_t& si, void *handler,
struct sigaction& siga)
{
bool interrupted;
/* Delay the interrupt if we are
1) somehow inside the DLL
2) in _sigfe (spinning is true) and about to enter cygwin DLL
3) in a Windows DLL. */
if (incyg || spinning || inside_kernel (cx))
interrupted = false;
else
{
_ADDR &ip = cx->_GR(ip);
push (ip);
interrupt_setup (si, handler, siga);
ip = pop ();
SetThreadContext (*this, cx); /* Restart the thread in a new location */
interrupted = true;
}
return interrupted;
}
void __reg3
_cygtls::interrupt_setup (siginfo_t& si, void *handler, struct sigaction& siga)
{
push ((__tlsstack_t) sigdelayed);
deltamask = siga.sa_mask & ~SIG_NONMASKABLE;
sa_flags = siga.sa_flags;
func = (void (*) (int, siginfo_t *, void *)) handler;
if (siga.sa_flags & SA_RESETHAND)
siga.sa_handler = SIG_DFL;
saved_errno = -1; // Flag: no errno to save
if (handler == sig_handle_tty_stop)
{
myself->stopsig = 0;
myself->process_state |= PID_STOPPED;
}
infodata = si;
this->sig = si.si_signo; /* Should always be last thing set to avoid race */
if (incyg)
set_signal_arrived ();
if (!have_execed && !(myself->exec_sendsig && !ch_spawn.iscygwin ()))
proc_subproc (PROC_CLEARWAIT, 1);
sigproc_printf ("armed signal_arrived %p, signal %d",
signal_arrived, si.si_signo);
}
extern "C" void __stdcall
set_sig_errno (int e)
{
*_my_tls.errno_addr = e;
_my_tls.saved_errno = e;
}
int
sigpacket::setup_handler (void *handler, struct sigaction& siga, _cygtls *tls)
{
CONTEXT cx;
bool interrupted = false;
if (tls->sig)
{
sigproc_printf ("trying to send signal %d but signal %d already armed",
si.si_signo, tls->sig);
goto out;
}
for (int n = 0; n < CALL_HANDLER_RETRY_OUTER; n++)
{
for (int i = 0; i < CALL_HANDLER_RETRY_INNER; i++)
{
tls->lock ();