glibc's tst-makecontext2 testcase uncovered a bug in
__cont_link_context. If the function misses to reserve
shadow space for the calls to setcontext/cygwin_exit,
both functions could overwrite memory beyond the stack
configured in uc_stack.
* exceptions.cc (__cont_link_context): x86_64: align stack and reserve
shadow space for subsequent function calls, otherwise suffer potential
buffer overflow.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* dcrt0.cc (initial_env): Reduce size of local path buffers to
PATH_MAX. Allocate debugger_command from process heap.
(init_windows_system_directory): Very early initialize new global
variable global_progname.
* dll_init.cc (dll_list::alloc): Make path buffer static. Explain why.
(dll_list::populate_deps): Use tmp_pathbuf for local path buffer.
* exceptions.cc (debugger_command): Convert to PWCHAR.
(error_start_init): Allocate debugger_command and fill with wide char
strings. Only allocate if NULL.
(try_to_debug): Just check if debugger_command is a NULL pointer to
return. Drop conversion from char to WCHAR and drop local variable
dbg_cmd.
* globals.cc (global_progname): New global variable to store Windows
application path.
* pinfo.cc (pinfo_basic::pinfo_basic): Just copy progname over from
global_progname.
(pinfo::status_exit): Let path_conv create the POSIX path to
avoid local buffer.
* pseudo_reloc.cc (__report_error): Utilize global_progname, drop local
buffer.
* smallprint.cc (__small_vsprintf): Just utilize global_progname for
%P format specifier.
(__small_vswprintf): Ditto.
* strace.cc (PROTECT): Change to reflect x being a pointer. Reformat.
(CHECK): Ditto. Reformat.
(strace::activate): Utilize global_progname, drop local buffer.
Fix formatting.
(strace::vsprntf): Reduce size of local progname buffer to NAME_MAX.
Copy and, if necessary, convert only the last path component to
progname.
(strace_buf_guard): New muto.
(buf): New static pointer.
(strace::vprntf): Use buf under strace_buf_guard lock only. Allocate
buffer space for buf on Windows heap.
* wow64.cc (wow64_respawn_process): Utilize global_progname, drop
local path buffer.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (__unwind_single_frame): Define empty macro on i686.
(_cygtls::call_signal_handler): Try to make sure signal context makes
sense in case we're generating context here. Add comment to explain.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (__unwind_single_frame): Move up in file to be
accessible from other places. Move comment to getcontext.
(stack_info::walk): Call __unwind_single_frame in 64 bit case. Fix
preceeding comment.
(myfault_altstack_handler): Call __unwind_single_frame.
(getcontext): Give comment from __unwind_single_frame a new home.
(swapcontext): Fix comment.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
x86_64 only:
* cygtls.cc (san::leave): Restore _my_tls.andreas.
* cygtls.h (class san): Add _clemente as in 32 bit case. Add ret and
frame members.
(san::san): Handle _my_tls.andreas as on 32 bit. Take parameter and
write it to new member ret. Store current stack pointer in frame.
(san::~san): New destructor to restore _my_tls.andreas.
(__try): Use __l_except address as parameter to san::san.
* dcrt0.cc (dll_crt0_0): Add myfault_altstack_handler as vectored
continuation handler.
* exception.h (myfault_altstack_handler): Declare.
* exceptions.cc (myfault_altstack_handler): New function. Explain what
it's good for.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* autoload.cc (SetThreadStackGuarantee): Import.
* cygtls.h (struct _cygtls): Replace thread_context with a ucontext_t
called context.
* exceptions.cc (exception::handle): Exit from process via signal_exit
in case sig_send returns from handling a stack overflow SIGSEGV.
Explain why.
(dumpstack_overflow_wrapper): Thread wrapper to create a stackdump
from another thread.
(signal_exit): Fix argument list to reflect three-arg signal handler.
In case we have to create a stackdump for a stack overflow condition,
do so from a separate thread. Explain why.
(sigpacket::process): Don't run signal_exit on alternate stack.
(altstack_wrapper): Wrapper function to do stack correction when
calling the signal handler on an alternate stack to handle a stack
overflow. Make sure to have lots of comments.
(_cygtls::call_signal_handler): Drop local context variable to reduce
stack pressure. Use this->context instead. Change inline assembler
to call altstack_wrapper.
(_cygtls::signal_debugger): Accommodate aforementioned change to
struct _cygtls.
* tlsoffset.h: Regenerate.
* tlsoffset64.h: Regenerate.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (_cygtls::call_signal_handler): Drop manipulating
thread's ss_flags here. It's not safe against longjmp.
* signal.cc (sigaltstack): Check if we're running on the alternate
stack and set ss_flags returned in oss to SS_ONSTACK.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (_cygtls::call_signal_handler): Drop pushing a register
on the original stack, it confuses GCC. Rearrange the assembler code
so that $rax/$eax is not used by GCC to prepare an argument value.
Use $rax/$eax without saving. Drop clearing $rbp/$epb.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (_cygtls::call_signal_handler): Drop subtracting 16
bytes from the alternate stack, it's not necessary. Safe all clobbered
registers. Safe one on the orignal stack, the others on the alternate
stack on both platforms.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (_cygtls::call_signal_handler): Disable enforcing
SA_RESTART in non-main threads to allow returning with EINTR from
system calls.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* exceptions.cc (call_signal_handler): Only bother to construct
the ucontext for signal handlers with SA_SIGINFO set. Set
mcontext.oldmask.
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
* exceptions.cc (call_signal_handler): Zero initialize context and set
context flags, as RlCaptureContext doesn't.
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Add ucontext.h header, defining ucontext_t and mcontext_t types.
Provide sigaction sighandlers with a ucontext_t parameter, containing stack and
context information.
* include/sys/ucontext.h : New header.
* include/ucontext.h : Ditto.
* exceptions.cc (call_signal_handler): Provide ucontext_t
parameter to signal handler function.
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
* cygtls.h (struct _cygtls): Convert thread_context to type CONTEXT.
* exceptions.cc (_cygtls::signal_debugger): Use sizeof (CONTEXT) for
size of CONTEXT copied for GDB's digestion.
* include/cygwin/signal.h: Add a preliminary comment.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This improves how stackinfo::dumpstack() dumps _sigbe and sigdelayed frames
* exceptions.cc (stack_info): Add sigstackptr member.
(walk): Unwind sigstackptr inside _sigbe and sigdelayed.
* gendef (_sigdelayed_end): Add symbol to mark end of sigdelayed.
Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
having a new type threadlist_t *. Convert commented out code into an
#if 0. Create thread mutex. Explain why.
(init_cygheap::remove_tls): Drop timeout value. Always wait infinitely
for tls_sentry. Return mutex HANDLE of just deleted threadlist entry.
(init_cygheap::find_tls): New implementation taking tls pointer as
search parameter. Return threadlist_t *.
(init_cygheap::find_tls): Return threadlist_t *. Define ix as auto
variable. Drop exception handling since crash must be made impossible
due to correct synchronization. Return with locked mutex.
* cygheap.h (struct threadlist_t): Define.
(struct init_cygheap): Convert threadlist to threadlist_t type.
(init_cygheap::remove_tls): Align declaration to above change.
(init_cygheap::find_tls): Ditto.
(init_cygheap::unlock_tls): Define.
* cygtls.cc (_cygtls::remove): Unlock and close mutex when finishing.
* exceptions.cc (sigpacket::process): Lock _cygtls area of thread before
accessing it.
* fhandler_termios.cc (fhandler_termios::bg_check): Ditto.
* sigproc.cc (sig_send): Ditto.
* thread.cc (pthread::exit): Ditto. Add comment.
(pthread::cancel): Ditto.
handler.
* cygtls.cc (_cygtls::remove): Accommodate the fact that pathbufs
has been moved from _local_storage to _cygtls.
* cygtls.h (class tls_pathbuf): Add comment to hint to gendef usage
of counters. Change type of counters to uint32_t for clarity.
Remove _cygtls as friend class.
(struct _local_storage): Move pathbufs from here...
(struct _cygtls): ...to here, allowing to access it from _sigbe.
(class san): Only define on 32 bit. Remove errno, _c_cnt and _w_cnt
members.
(san::setup): Drop parameter. Don't initialize removed members.
(san::leave): Don't set removed members.
(class myfault): Only define on 32 bit.
(myfault::faulted): Only keep implementation not taking any parameter.
Drop argument in call to sebastian.setup.
(__try/__leave/__except/__endtry): Implement to support real SEH. For
now stick to SJLJ on 32 bit.
* dcrt0.cc (dll_crt0_0): Drop 64 bit call to
exception::install_myfault_handler.
* exception.h (exception_handler): Define with EXCEPTION_DISPOSITION
as return type.
(PDISPATCHER_CONTEXT): Define as void * on 32 bit. Define as pointer
to _DISPATCHER_CONTEXT on 64 bit.
(class exception): Define separately for 32 and 64 bit.
(exception::myfault): Add handler for myfault SEH handling on 64 bit.
(exception::exception): Fix mangled method name to account for change
in type of last parameter.
(exception::install_myfault_handler): Remove.
* exceptions.cc (exception::myfault_handle): Remove.
(exception::myfault): New SEH handler for 64 bit.
* gendef (_sigbe): Set tls_pathbuf counters to 0 explicitely when
returning to the caller.
* ntdll.h: Move a comment to a better place.
(struct _SCOPE_TABLE): Define on 64 bit.
* thread.cc (verifyable_object_isvalid): Remove gcc 4.7 workaround.
* tls_pbuf.cc (tls_pbuf): Fix to accommodate new place of pathbufs.
(tls_pathbuf::destroy): Change type of loop variables to uint32_t.
* tls_pbuf.h (class tmp_pathbuf): Change type of buffer counters to
uint32_t. Accommodate new place of pathbufs.
* tlsoffsets.h: Regenerate.
* tlsoffsets64.h: Regenerate.
* exceptions.cc (_cygtls::signal_debugger): Reorganize to avoid contacting the
debugger if we have already done so via the exception handler. Eliminate need
for goto. Remove an ifdef in favor of just allocating a larger buffer.
* exception.h (exception_list): Typedef as void on x86_64.
(exception::handler_installed): Remove.
(exception::handle_while_being_debugged): Remove.
(exception::myfault_handle): Declare for x86_64.
(exception::handle): Declare as ordinary exception handler on x86_64
as well.
(exception::exception): Drop previous code (again). Install
exception::handle as SEH handler.
(exception::install_myfault_handler): New x86_64-only method to
install exception::myfault_handle as VEH handler. Explain why.
(exception::~exception): For x86_64, define frame end label (again).
* exceptions.cc (CYG_EXC_CONTINUE_EXECUTION): Drop definition.
(CYG_EXC_CONTINUE_SEARCH): Ditto.
(exception::myfault_handle): New x86_64-only method, VEH handler to
handle myfault exceptions.
(exception::handle): Define as ordinary exception handler on x86_64
as well. Use ExceptionContinueExecution and ExceptionContinueSearch
throughout instead of deleted Cygwin macros. Don't handle myfault
exceptions on x86_64.
class.
(cygwin_exception::h): New member.
(cygwin_exception::cygwin_exception): Initialize h to NULL.
* exceptions.cc (cygwin_exception::open_stackdumpfile): Move into
cygwin_exception class. Use 'h' class member.
(cygwin_exception::dumpstack): Close stack dump file handle if opened.
included by default.
* winlean.h: Add long comment to explain why we have to define certain
symbols.
(_NORMALIZE_): Define.
(_WINNLS_): Drop definition and subsequent undef.
(_WINNETWK_): Ditto.
(_WINSVC_): Ditto.
2013-11-23 Eric Blake <eblake@redhat.com>
essentially guarded by thread-specific signal_arrived.
* exceptions.cc (_cygtls::handle_SIGCONT): Simplify. Eliminate lock/unlock
since code is guarded by signal_arrived.
Corinna Vinschen
Jon TURNEY
Christopher Faylor