This patch has been inspired by the Linux kernel patch
294f69e662d1 compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use
written by Joe Perches <joe AT perches DOT com> based on an idea from
Dan Carpenter <dan DOT carpenter AT oracle DOT com>. The following text
is from the original log message:
Reserve the pseudo keyword 'fallthrough' for the ability to convert the
various case block /* fallthrough */ style comments to appear to be an
actual reserved word with the same gcc case block missing fallthrough
warning capability.
All switch/case blocks now should end in one of:
break;
fallthrough;
goto <label>;
return [expression];
continue;
In C mode, GCC supports the __fallthrough__ attribute since 7.1,
the same time the warning and the comment parsing were introduced.
Cygwin-only: add an explicit -Wimplicit-fallthrough=5 to the build
flags.
Introducing an independent Cygwin PID introduced a regression:
The expectation is that the myself pinfo pointer always points to a
specific address right in front of the loaded Cygwin DLL.
However, the independent Cygwin PID changes broke this. To create
myself at the right address requires to call init with h0 set to
INVALID_HANDLE_VALUE or an existing address:
void
pinfo::init (pid_t n, DWORD flag, HANDLE h0)
{
[...]
if (!h0 || myself.h)
[...]
else
{
shloc = SH_MYSELF;
if (h0 == INVALID_HANDLE_VALUE) <-- !!!
h0 = NULL;
}
The aforementioned commits changed that so h0 was always NULL, this way
creating myself at an arbitrary address.
This patch makes sure to set the handle to INVALID_HANDLE_VALUE again
when creating a new process, so init knows that myself has to be created
in the right spot. While at it, fix a potential uninitialized handle
value in child_info_spawn::handle_spawn.
Fixes: b5e1003722 ("Cygwin: processes: use dedicated Cygwin PID rather than Windows PID")
Fixes: 88605243a1 ("Cygwin: fix child getting another pid after spawnve")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
In dll_crt0_0, both threadinterface->Init and sigproc_init allocate
windows object handles using unpredictable memory regions, which may
collide with dynamically loaded dlls when they were relocated.
When calling spawnve, in contrast to execve, the parent has
to create the pid for the child. With the old technique
this was simply the Windows pid, but now we have to inform
the child about its new pid.
Add a cygpid member to class child_info_spawn. Set it in
child_info_spawn::worker, just prior to calling CreateProcess
rather than afterwards. Overwrite cygheap->pid in
child_info_spawn::handle_spawn before calling pinfo::thisproc.
Make sure pinfo::thisproc knows the pid is already set by
setting the handle argument to INVALID_HANDLE_VALUE.
Also set procinfo->dwProcessId to myself_initial.dwProcessId
instead of to myself_initial.pid for clarity.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
To support in-cygwin package managers, the fork() implementation must
not rely on .exe and .dll files to stay in their original location, as
the package manager's job is to replace these files. Instead, when the
first fork try fails, and we have NTFS, we use hardlinks to the original
binaries in /var/run/cygfork/ to create the child process during the
second fork try, along the main.exe.local file to enable the "DotLocal
Dll Redirection" feature for the dlls.
The (probably few) users that need an update-safe fork manually have to
create the /var/run/cygfork/ directory for now, using:
mkdir --mode=a=rwxt /var/run/cygfork
* child_info.h: Bump CURR_CHILD_INFO_MAGIC.
(enum child_status): Add _CI_SILENTFAIL flag.
(struct child_info): Add silentfail setter and getter.
* winsup.h (child_copy): Add bool silentfail parameter.
* cygheap.cc: Pass silentfail parameter to child_copy.
* dcrt0.cc: Ditto.
* dll_init.h (struct dll): Define public inline method forkedntname.
(struct dll_list): Declare private method find_by_forkedntname.
* dll_init.cc (struct dll_list): Implement find_by_forkedntname.
(dll_list::alloc): Use find_by_forkedntname when in load after fork.
(dll_list::load_after_fork_impl): Load dlls using dll::forkedntname.
* fork.cc (frok::parent): Set silentfail child info flag. Pass
silentfail parameter to child_copy. Use forkedntname of
dlls.main_executable.
(fork): When first dofork run failed and did not use forkables,
run dofork again with_forkables set to true.
(child_copy): Use debug_printf if silentfail is true,
system_printf otherwise.
Using the Windows PID as Cygwin PID has a few drawbacks:
- the PIDs on Windows get reused quickly. Some POSIX applications choke
on that, so we need extra code to avoid too quick PID reuse.
- The code to avoid PID reuse keeps parent process handles and
(depending on a build option) child processes open unnecessarily.
- After an execve, the process has a split personality: Its Windows PID
is a new PID, while its Cygwin PID is the PID of the execve caller
process. This requires to keep two procinfo shared sections open, the
second just to redirect process info requests to the first, correct
one.
This patch changes the way Cygwin PIDs are generated:
- Cygwin PIDs are generated independently of the Windows PID, in a way
expected by POSIX processes. The PIDs are created incrementally in
the range between 2 and 65535, round-robin.
- On startup of the first Cygwin process, choose a semi-random start PID
for the first process in the lower PID range to make the PIDs slightly
unpredictable. This may not be necessary but it seems kind of inviting
to know that the first Cygwin process always starts with PID 2.
- Every process not only creates the shared procinfo section, but also a
symlink in the NT namespace, symlinking the Windows PID to the Cygwin
PID. This drops the need for the extra procinfo section after execve.
- Don't keep other process handles around unnecessarily.
- Simplify the code creating/opening the shared procinfo section and
make a clear distinction between interfaces getting a Cygwin PID and
interfaces getting a Windows PID.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Keeping an inheritable handle open results in that handle being
spilled over into grandchild processes, which is not desired.
Duplicate original parent handle into a non-inheritable one with
minimal SYNCHRONIZE permissions and close the original handle.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This test was broken from the start. It leads to creating a completely
new stack for the main thread of the child process when started from
the main thread of the parent. However, the main thread of a process
can easily running on a completely different stack, if the parent's main
thread was created by calling fork() from a pthread. For an example,
see https://cygwin.com/ml/cygwin/2017-03/msg00113.html
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
GDB since commit 24cdb46e [1] can report and use these names.
Add utility function SetThreadName(), which sends a thread name to the
debugger.
Use that:
- to set the default thread name for main thread and newly created pthreads.
- in pthread_setname_np() for user thread names.
- for helper thread names in cygthread::create()
- for helper threads which are created directly with CreateThread.
Note that there can still be anonymous threads, created by system or
injected DLLs.
[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=24cdb46e9f0a694b4fbc11085e094857f08c0419
The _reent members _current_category and _current_locale are not
used at all. _current_locale is set to "C" in various points of
the code but its value is just as unused as _current_category.
This patch redefines these members without changing the size of the
structure to allow for an implementation of per-thread locales per
POSIX-1.2008 (i.e. uselocale and usage of the per-thread locale in
subsequent function calls).
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Bump GPLv2+ to GPLv3+ for some files, clarify BSD 2-clause.
Everything else stays under GPLv3+.
New Linking Exception exempts resulting executables from LGPLv3 section 4.
Add CONTRIBUTORS file to keep track of licensing.
Remove 'Copyright Red Hat Inc' comments.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* dcrt0.cc (dll_crt0_1), environ.cc (environ_init, getwinenveq,
build_env), strfuncs.cc (sys_wcstombs, sys_wcstombs_alloc),
wchar.c (sys_wcstombs, sys_wcstombs_alloc): avoid mis-conversions
of text that does not, actually, refer to a path or file name
Detailed explanation:
Our WCS -> UTF conversion handles the private Unicode page specially
to allow for otherwise invalid file names. However, this handling makes
no sense for command-lines, nor environment variables, which we would
rather convert verbatim.
As a stop-gap solution, let's just introduce a version of the
sys_wcstombs() function that specifically excludes that file name
conversion magic.
The proper solution is to change sys_wcstombs() to assume that it is not
a path that wants to be converted, and introduce sys_wcstombs_path()
that does, but that is a bigger task which we leave for another patch.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
* dcrt0.cc: Semi-revert commit 12743c2d5d.
(dll_crt0_0): Drop setting wow64_needs_stack_adjustment on 64 bit.
(_dll_crt0): Split out 64 bit code again and always create new main
thread stack, unless forked off from the non main thread in the parent.
Call create_new_main_thread_stack with parent stack commitsize if
started from the parent's main thread.
Only call child_info_fork::alloc_stack for the latter case on 64 bit.
Slightly rearrange moving rsp and rbp to new stack and document how.
Revert 32 bit wow64 handling to its former self.
* miscfunc.cc (create_new_main_thread_stack): Take a commitsize
parameter and use it if it's not 0. Don't set _main_tls here, it's
done in the caller _dll_crt0 anyway. Return stackbase - 16 bytes,
rather than stacklimit (which was very wrong anyway).
* miscfuncs.h (create_new_main_thread_stack): Accommodate declaration
to aforementioned change.
* wincap.h (wincaps::has_3264_stack_broken): Remove element.
* wincap.cc: Ditto, throughout.
* wow64.cc: Semi-revert to pre-12743c2d5d2721f3a80b4d7671a349be03c1f520
but keep architecture-agnostic type changes intact. Fix formatting.
* wow64.h: Revert to pre-12743c2d5d2721f3a80b4d7671a349be03c1f520.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* dcrt0.cc (dll_crt0_0): On 64 bit, set wow64_needs_stack_adjustment
if not started from a 64 bit process.
(_dll_crt0): Enable wow64_needs_stack_adjustment branch on 64 bit
as well. Remove 64 bit only code. Introduce CREATE_STACK and
FIX_STACK macros to conditionalize the code. Rearrange and
partially rewrite comments.
* wincap.h (wincaps::has_3264_stack_broken): New element.
* wincap.cc: Implement above element throughout.
(wincapc::init): Set has_3264_stack_broken to false on 32 bit.
* wow64.cc: Enable functionality on 64 bit architecture, except for
wow64_revert_to_original_stack. Enhance comments to explain.
(wow64_eval_expected_main_stack): Make 64 bit clean.
(wow64_test_for_64bit_parent): Ditto.
* wow64.h: Export wow64_revert_to_original_stack on 32 bit only,
everything else on all architectures.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* child_info.h (CURR_CHILD_INFO_MAGIC): Align to below change.
(class child_info_fork): Rename stacktop to stacklimit. Rename
stackbottom to stackbase. Accommodate name change throughout Cygwin.
Rephrase comments to be clearer.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* cygtls.h (_tlsbase): Remove. Replace throughout with
NtCurrentTeb()->Tib.StackBase.
(_tlstop): Remove. Replace throughout with
NtCurrentTeb()->Tib.StackLimit.
* dcrt0.cc (child_info_fork::alloc_stack): Move definition of local
teb variable up to be used throughout.
* include/cygwin/config.h (__getreent): Use inline function on both
architectures.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
* strfuncs.cc (sys_cp_wcstombs): Always return number of multibytes
without trailing NUL as the documentation implies. Throughout Cygwin,
fix usage to align to this pattern.
* fhandler_process.cc (format_process_winexename): Drop trailing NUL
and LF from output.
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>
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>
API version numbers.
* external.cc (cygwin_internal): disable setting cxx_malloc on 64 bit.
Add CW_FIXED_ATEXIT case.
* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Bump.
* include/sys/cygwin.h (cygwin_getinfo_types): Add CW_FIXED_ATEXIT.
* lib/atexit.c (atexit): Test running Cygwin version by checking
return value of cygwin_internal (CW_FIXED_ATEXIT).
* lib/atexit.c (atexit): New, statically linkable version of atexit.
* dcrt0.cc (cygwin_atexit): Add comment to mark this function as old
entry point. Indiscriminately check for DSO of function pointer for
all functions, if checking for DSO of return address fails on x86_64.
Change comment accordingly.
(init_cygheap::init_installation_root): Just memmove contents of
installation_root instead of calling GetModuleFileNameW again.
Copy installation_root to installation_dir before stripping of
"bin" dir. Don't call SetDllDirectory here. Explain what we do.
(setup_cygheap): New function taking over initial cygheap setup
from memory_init. Additionally call set_dll_dir.
* cygheap.h (struct init_cygheap): Add installation_dir member.
(init_cygheap::set_dll_dir): Define.
(setup_cygheap): Declare.
* dcrt0.cc: Throughout drop parameter from memory_init call.
(dll_crt0_0): Call setup_cygheap prior to memory_init.
* dlfcn.cc (dlopen): Change comment to point to the right function.
* shared.cc (memory_init): Drop parameter. Drop cygheap setup.
* shared_info.h (memory_init): Change declaration accordingly.
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.
* dcrt0.cc (initial_env): Drop strlwr calls. Call strcasestr instead.
* fhandler_netdrive.cc: Throughout, convert to calling WNet UNICODE
functions. Use tmp_pathbuf rather than alloca. Replace call to
strlwr with call to RtlDowncaseUnicodeString.
* dcrt0.cc (cygwin_atexit): Use d->handle with __cxa_atexit.
* dll_init.cc (dll_list::detach): Use d->handle with __cxa_finalize.
* include/cygwin/version.h (CYGWIN_VERSION_API_MINOR): Use 274 for
__cxa_finalize as well.
* 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.
with additional argument to specify if the process has been execed
or spawned.
* flock.cc (fixup_lockf_after_exec): Take bool parameter to handle
exec and spawn differently. In case of spawn, just give up POSIX
locks in favor of the still running parent. Add comments to explain.
Corinna Vinschen
Michael Haubenwallner
Jon Turney
Peter Foley
Johannes Schindelin
Yaakov Selkowitz
Christopher Faylor