The original dll_init code was living under the wrong assumption that
dll_dllcrt0_1 and in turn dll_list::alloc will be called for each
LoadLibrary call. The same wrong assumption was made for
cygwin_detach_dll/dll_list::detach called via FreeLibrary.
In reality, dll_dllcrt0_1 gets only called once at first LoadLibrary
and cygwin_detach_dll once at last FreeLibrary.
In effect, reference counting for DLLs was completely broken after fork:
parent:
l1 = dlopen ("lib1"); // LoadLibrary, LoadCount = 1
l2 = dlopen ("lib1"); // LoadLibrary, LoadCount = 2
fork (); // LoadLibrary in the child, LoadCount = 1!
child:
dlclose (l1); // FreeLibrary actually frees the lib
x = dlsym (l2); // SEGV
* Move reference counting to dlopen/dlclose since only those functions
have to keep track of loading/unloading DLLs in the application context.
* Remove broken accounting code from dll_list::alloc and dll_list::detach.
* Fix error handling in dlclose.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Note that this always returns with dli_sname and dli_saddr set to NULL,
indicating no symbol matching addr could be found.
Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
On 09/02/2016 11:03 AM, Corinna Vinschen wrote:
> On Sep 2 10:46, Michael Haubenwallner wrote:
>> On 09/01/2016 03:32 PM, Corinna Vinschen wrote:
>>> You could just use the global variable program_invocation_name. If in
>>> doubt, use the Windows path global_progname and convert it to full POSIX
>>> via cygwin_conv_path.
>>
>> Patch updated, using global_progname now.
>
> Looks good and you're right to do it this way since I just noticed
> that program_invocation_name may return a relative pathname.
Yep.
> Btw., in other calls which require the full POSIX path we use
> mount_table->conv_to_posix_path instead of cygwin_conv_path (see
> e. g. fillout_pinfo()). It's a bit faster. Maybe something for a
> followup patch.
No problem - attached.
This renders the original patch 4/4 valid again.
> Note for some later improvement: I really wonder why we don't store
> the absolute POSIX path of the current executable globally yet...
Same here.
Thanks!
/haubi/
>From f7255edd33cb4abe34f27188aab8dccdfa5dd2a0 Mon Sep 17 00:00:00 2001
From: Michael Haubenwallner <michael.haubenwallner@ssi-schaefer.com>
Date: Wed, 31 Aug 2016 18:05:11 +0200
Subject: [PATCH 3/4] dlopen: on x/lib search x/bin if exe is in x/bin
citing https://cygwin.com/ml/cygwin-developers/2016-08/msg00020.html
> Consider the file /usr/bin/cygz.dll:
> - dlopen (libz.so) success
> - dlopen (/usr/bin/libz.so) success
> - dlopen (/usr/lib/libz.so) fails
* dlfcn.c (dlopen): For dlopen("x/lib/N"), when the application
executable is in "x/bin/", search for "x/bin/N" before "x/lib/N".
Instead of find_exec, without changing behaviour use new pathfinder
class with new allocator_interface around tmp_pathbuf and new vstrlist
class.
* pathfinder.h (pathfinder): New file.
* vstrlist.h (allocator_interface, allocated_type, vstrlist): New file.
* dlfcn.cc (dlopen): Avoid redundant GetModuleHandleExW with RTLD_NOLOAD
and RTLD_NODELETE. Switch to new pathfinder class, using
(tmp_pathbuf_allocator): New class.
(get_full_path_of_dll): Drop.
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>
We're appending a dot to the filename before calling LoadLibrary to
override ".dll" automagic. This only worked for paths, not for simple
filenames since it required a slash in the pathname. Fix that.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
(gfpod_helper): Drop equality sign from environment variable name
in call to check_path_access.
* exec.cc (execlp): Drop equality sign from environment variable name
in call to find_exec.
(execvp): Ditto.
(execvpe): Ditto.
* path.h (enum fe_types): Drop FE_NATIVE.
(find_exec): Rename third paramter in declaration from search. Drop
equality sign from default value.
* spawn.cc (perhaps_suffix): Add PC_POSIX to path_conv::check call.
(find_exec): Simplify function. Iterate over POSIX pathlist rather
than Windows pathlist. Drop handling of FE_NATIVE flag. Always fill
posix path of incoming path_conv buf, unless FE_NNF flag is given.
(av::setup): Drop equality sign from environment variable name
in call to find_exec. Call unshift with normalized_path.
* winf.cc (av::unshift): Drop conv parameter and code converting
Windows to POSIX path.
* winf.h (av::unshift): Accommodate prototype.
(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.
installation dir as DLL search path, instead of ".".
* cygheap.h (class cwdstuff): Add parameter names in function
declarations for readability.
(cwdstuff::get): Ad inline implementation fetching the CWD as wide char
string.
* dlfcn.cc (dlopen): Add searching for dependent DLLs in DLL
installation dir or CWD, if all else failed.
Add comment to explain scenarios this is accommodating.
(check_path_access): Ditto. Drop FE_CWD from call to find_exec.
(gfpod_helper): Call path_conv::check for all paths containing a dir
separator to more closely follow the Linux search algorithm.
(get_full_path_of_dll): Drop useless __stdcall.
(dlopen): Simplify RTLD_NOLOAD case by calling GetModuleHandleEx
instead of GetModuleHandle/LoadLibrary.
a given DLL name. Change default search path to allow /usr/bin.
(get_full_path_of_dll): Find DLLs even if the caller used a ".so"
suffix or a "lib" prefix for the DLL.
* dlfcn.cc: Throughout mark exported symbols as extern "C".
(dlopen): Unignore flags argument. Define ret to NULL. Fix typo in
comment. Support Glibc flags RTLD_NOLOAD and RTLD_NODELETE.
* include/dlfcn.h: Clean up comments.
(RTLD_NODELETE): Define.
(RTLD_NOLOAD): Define.
(RTLD_DEEPBIND): Define.
* dlfcn.cc (dlopen): Make sure errno is set if an error occurs.
(dlsym): Rewrite using RtlQueryProcessDebugInformation instead of
EnumProcessModules.
* ntdll.h (struct _DEBUG_MODULE_ARRAY): Define.
(RtlCreateQueryDebugBuffer): Declare.
(RtlDestroyQueryDebugBuffer): Declare.
(RtlQueryProcessDebugInformation): Declare.
(_cygtls::andreas): Convert to a pointer.
(san): Convert to a real class with methods. Use a linked list to keep track
of previous handlers on the "stack".
(myfault): Rewrite to use new san class rather than calling directly into
_cygtls.
* cygtls.cc (_cygtls::init_exception_handler): Just assume that we're always
using the standard exception handler.
(_cygtls::init_thread): Reflect loss of argument to init_exception_handler.
* dcrt0.cc (dll_crt0_1): Ditto.
* dfcn.cc (dlopen): Ditto.
(dlclose): Reset the exception handler after FreeLibrary.
* dll_init.cc (dll_list::detach): Make sure that the exception handler is
initialized before calling destructors.
* exceptions.cc (_cygtls::handle_exceptions): Accommodate new andreas pointer.
* thread.cc (verifyable_object_isvalid): Pass objectptr to faulted for explicit
NULL pointer checking.
* tlsoffsets.h: Regenerate.
local path_conv in favor of getting it as parameter. Add local string
buffer instead of getting it as parameter.
(dlopen): Accommodate get_full_path_of_dll change. Fetch WCHAR Windows
path from path_conv variable and call LoadLibraryW.
Unconditionally handle mount points case-sensitive.
Unconditionally handle virtual paths case-sensitive.
Unconditionally handle registry paths case-insensitive.
Otherwise, accommodate case-sensitivity of given path throughout.
* cygheap.cc (cygheap_root::set): Get additional caseinsensitive
parameter and store it.
* cygheap.h (struct cygheap_root_mount_info): Add member
caseinsensitive.
* dlfcn.cc (get_full_path_of_dll): Drop PC_NOFULL parameter from call
to path_conv::check.
* environ.cc (pcheck_case): Remove.
(check_case_init): Remove.
(known): Drop "check_case" option.
* exceptions.cc (open_stackdumpfile): Add comment.
* fhandler.cc (fhandler_base::get_default_fmode): Call pathmatch
instead of strcasematch.
* fhandler_disk_file.cc: Accommodate case-sensitivity of given path
throughout.
(__DIR_mounts::check_mount): Unconditionally check virtual paths
case-sensitive.
(fhandler_disk_file::link): Drop case clash handling.
(fhandler_disk_file::open): Ditto.
(fhandler_disk_file::readdir_helper): Drop managed mount code.
* mount.cc: Remove managed mount code and datastructures.
(struct opt): Remove "managed" option. Add "posix=0" and "posix=1"
options.
(fillout_mntent): Remove "managed" output. Add "posix" output.
* path.cc (struct symlink_info): Remove case_clash member and
case_check method.
(pcheck_case): Remove.
(path_prefix_p): Take additional bool parameter "caseinsensitive".
(pathnmatch): Ditto.
(pathmatch): Ditto.
(mkrelpath): Ditto.
(fs_info::update): Set caseinsensitive flag according to file system
name and FILE_CASE_SENSITIVE_SEARCH flag. Add comment.
(tfx_chars_managed): Remove.
(transform_chars): Drop "managed" parameter. Always use tfx_chars.
(get_nt_native_path): Drop "managed" parameter. Make sure drive letters
are always upper case.
(getfileattr): Change second parameter to denote caseinsensitivity.
(path_conv::check): Initialize caseinsensitive to OBJ_CASE_INSENSITIVE.
Set caseinsensitive according to global obcaseinsensitive flag, file
system case sensitivity and MOUNT_NOPOSIX mount flag.
Drop case_clash and all the related code.
(symlink_worker): Drop case clash handling.
(symlink_info::set): Drop setting case_clash.
(symlink_info::case_check): Remove.
(cwdstuff::set): Add comment.
(etc::init): Take path_conv instead of PUNICODE_STRING as parameter to
allow case sensitivity.
* path.h (enum pathconv_arg): Drop PC_SYM_IGNORE.
(enum case_checking): Remove.
(enum path_types): Drop PATH_ENC, add PATH_NOPOSIX flag.
(struct fs_info): Add caseinsensitive flag and accessor methods.
(class path_conv): Add caseinsensitive member and define
objcaseinsensitive method. Drop case_clash member and isencoded method.
(pathmatch): Change prototype according to above change.
(pathnmatch): Ditto.
(path_prefix_p): Ditto.
(get_nt_native_path): Ditto.
(class etc): Ditto.
(fnunmunge): Remove prototype.
* shared.cc (shared_info::init_obcaseinsensitive): Initialize
obcaseinsensitive flag from obcaseinsensitive registry value.
(shared_info::initialize): Call init_obcaseinsensitive here by the
first process creating the shared memory.
* shared_info.h (mount_item::fnmunge): Remove.
(shared_info::obcaseinsensitive): Rename from obcaseinsensitivity.
(shared_info::init_obcaseinsensitive): Declare.
* syscalls.cc (try_to_bin): Add comment.
* include/sys/mount.h (MOUNT_ENC): Remove flag.
(MOUNT_NOPOSIX): Add flag.
* path.h (enum fe_types): Add FE_DLL value.
* spawn.cc (std_suffixes): Remove.
(exe_suffixes): New suffix_info for executing files.
(dll_suffixes): New suffix_info for searching shared libraries.
(perhaps_suffix): Add opt argument. Use dll_suffixes if FE_DLL
option is given, exe_suffixes otherwise.
(find_exec): Propagate opt argument to perhaps_suffix. Drop suffix
check when testing execute permission.
(spawn_guts): Call perhaps_suffix with FE_NADA opt argument.
variable.
* dlfcn.cc (get_full_path_of_dll): Search /usr/bin (for windows compatibility)
and /usr/lib (for UNIX compatibility) when looking for shared libraries.
* environ.cc (conv_envvars): Put back LD_LIBRARY_PATH since it is used by
get_full_path_of_dll().
* errno.cc (errmap): Map MOD_NOT_FOUND to ENOENT.
* cygmagic: Remove debugging cruft.
* fhandler.h (select_record::thread_errno): Save any encountered errno here.
(select_record::set_select_errno): New function.
(select_record::saw_error): New function.
(select_record::select_record): Initialize thread_errno to zero.
* select.cc (set_handle_or_return_if_not_open): Set thread_errno on failure.
(select_stuff::wait): Record errno for later resurrection in calling thread.
(peek_serial): Ditto.
compiler bug.
* autoload.cc (TryEnterCriticalSection): Remove.
* dcrt0.cc (dll_crt0_0): Delete inappropriate setting of _my_tls.stackptr to
NULL since it has really bad consequences. Make 'si' an automatic variable.
* cygtls.cc (_threadinfo::init_thread): Correct thinko which caused thread list
to be allocated every time.
* cygtls.h (CYGTLS_PADSIZE): Define as const int.
* sync.h: Make multiple inclusion safe.
(muto::next): Eliminate.
(muto::exiting_thread): New variable.
(muto::set_exiting_thread): New function.
(new_muto): Change to use different section for mutos since c++ give
inexplicable warning in some cases otherwise.
(new_muto1): Ditto.
* dcrt0.cc (do_exit): Call muto::set_exiting_thread here.
* sync.cc (muto_start): Eliminate.
(muto::acquire): Always give exiting thread a lock. Never give thread a lock
if exiting.
(muto::release): Ditto for releasing.
* dtable.cc (dtable::init_lock): Unline function and define here.
* dtable.h (lock_cs): Define as a muto since critical sections seem to work
oddly on Windows Me.
(lock): Accommodate switch to muto.
(unlock): Ditto.
* exceptions.cc (setup_handler): Don't worry about acquiring mutos since that
hasn't mattered for a long time.
(signal_exit): Ditto: muto stuff will be handled automatically on exit now.
* Makefile.in (DLL_IMPORTS): Link advapi32 to ensure proper DLL initialization.
* autoload.cc (RegCloseKey): Arbitrarily choose this function as a "seed" to
pull the advapi32 link library in. So, comment out the autoloading.
* cygtls.cc (_threadinfo::init_thread): Just clear CYGTLS_PADSIZE.
(_threadinfo::remove): Add debugging.
(_threadinfo::find_tls): Ditto.
* cygtls.h (_threadinfo::padding): Make zero length (for now?).
* dcrt0.cc (dll_crt0_0): Move more initialization here from dll_crt0_1.
(dll_crt0_1): See above.
* dtable.h (dtable::lock): Remove commented out critical section locking.
* dtable.h (dtable::init_lock): Remove commented out critical section locking.
* dtable.h (dtable::unlock): Remove commented out critical section locking.
* exceptions.cc (interruptible): bool'ize.
* init.cc (threadfunc_fe): Revert to storing threadfunc at stack bottom.
(munge_threadfunc): Ditto. Avoid adding overhead to calibration_thread.
(prime_threads): Don't initialize tls stuff.
(dll_entry): Make minor change to initialization order.
* tlsoffsets.h: Regenerate.
* sigproc.cc (wait_sig): Add sanity check for end of process thread exit.
* select.h: Make minor formatting change.
* Makefile.in: Add still more -fomit-frame-pointer functions.
* dtable.h (dtable::lock): New function.
(dtable::unlock): New function.
(dtable::init_lock): New function.
* cygheap.h (HEAP_TLS): Declare new enum value.
(init_cygheap::threadlist): Declare new array.
(init_cygheap::sthreads): Declare new variable.
(cygheap_fdmanip::~cygheap_fdmanip): Use new dtable lock/unlock functions.
(cygheap_fdnew::cygheap_fdnew): Ditto.
(cygheap_fdget::cygheap_fdget): Ditto.
* dtable.cc (dtable_init): Initialize fdtab critical section.
(dtable::fixup_after_fork): Ditto.
(dtable::fixup_after_exec): Ditto.
(dtable::dup2): Use lock/unlock calls to protect access to fdtab.
(dtable::find_fifo): Ditto.
(dtable::fixup_before_fork): Ditto.
(dtable::fixup_before_exec): Ditto.
(dtable::set_file_pointers_for_exec): Ditto.
(dtable::vfork_child_dup): Ditto.
(dtable::vfork_parent_restore): Ditto.
* syscalls.cc (close_all_files): Ditto.
* sync.h (muto::acquired): Declare new function.
(new_muto1): Declare new macro used to specify name of muto storage.
* sync.cc (muto::acquired): Define new function.
* cygthread.cc (cygthread::stub): Remove signal chain removal call since it is
handled during initialization now.
* cygthread.cc (cygthread::simplestub): Remove signal chain removal call since
it is handled during initialization now.
* cygtls.cc (sentry): New class used for locking. Use throughout.
(_threadinfo::reset_exception): Don't pop stack.
(_threadinfo::find_tls): Move from exceptions.cc.
(_threadinfo::init_thread): Initialize array of threads rather than linked
list. Take second argument indicating thread function for this thread.
(_threadinfo::remove): Search thread array rather than linked list. Use sentry
to lock. Only unlock if we got the lock.
(_threadinfo::find_tls): Ditto for first two.
(handle_threadlist_exception): Handle exceptions when manipulating the thread
list in case of premature thread termination.
(_threadinfo::init_threadlist_exceptions): Ditto.
* cygtls.h (TLS_STACK_SIZE): Decrease size.
(_threadinfo::padding): Add element to avoid overwriting lower part of stack.
(_threadinfo::remove): Add a "wait" argument to control how long we wait for a
lock before removing.
* exceptions.cc (init_exception_handler): Make global. Take argument to
control exception handler being set.
(ctrl_c_handler): Wait forever when removing self from signal chain.
(_threadinfo::find_tls): Move to cygtls.cc.
(sig_handle): Reorganize detection for thread-specific signals.
* heap.cc (heap_init): Rework slightly. Make fatal error more verbose. Remove
malloc initialization since it can't happen during dll attach.
* init.cc (search_for): Move address to search for on stack here.
(threadfunc_ix): Ditto for stack offset. Make shared so that stack walk
potentially only has to be done once when cygwin processes are running.
(threadfunc_fe): Use standard tls to store thread function (may change back
later).
(calibration_thread): New function. Potentially called to find threadfunc_ix.
(munge_threadfunc): Search for "search_for" value on stack. Output warning
when thread func not found on stack. Use standard tls to store thread
function.
(prime_threads): New function. Called to prime thread front end.
(dll_entry): Call dll_crt0_0 here when DLL_PROCESS_ATTACH. Call prime_threads
here. Try to remove thread from signal list here.
* sigproc.cc (wait_sig): Initialize threadlist exception stuff here.
* thread.cc (pthread::exit): Pass argument to signal list remove function.
* thread.h: Remove obsolete *ResourceLock defines.
* tlsoffsets.h: Regenerate.
* winsup.h (spf): Define temporary debug macro to be deleted later.
* dcrt0.cc (dll_crt0_0): New function, called during DLL initialization.
Mainly consists of code pulled from dll_crt0_1.
(dll_crt0_1): See above.
(_dll_crt0): Wait for initial calibration thread to complete, if appropriate.
Move some stuff to dll_crt0_0.
(initialize_main_tls): Accommodate argument change to
_thread_info::init_thread.
* fork.cc (fork_child): Ditto.
(sync_with_child): Fix debug message.
* external.cc (cygwin_internal): Remove special considerations for
uninitialized dll since initialization happens during dll attach now.
* dlfcn.cc (dlopen): Remove obsolete *ResourceLock calls.
(dlclose): Ditto.
* cygheap.h (init_cygheap::close_ctty): Declare new function.
* cygheap.cc (init_cygheap::close_ctty): Define new function.
* syscalls.cc (close_all_files): Use close_ctty.
(setsid): Ditto.
* cygthread.cc (cygthread::stub): Remove exception initialization.
* cygthread.cc (cygthread::stub): Remove exception initialization.
(cygthread::simplestub): Ditto.
* thread.cc (pthread::thread_init_wrapper): Ditto.
* cygtls.cc (_last_thread): Make static.
(_threadinfo::call2): Initialize exception handler here.
(_threadinfo::find_tls): Move here.
* exceptions.cc (_threadinfo::find_tls): Move.
* dcrt0.cc (__api_fatal): Add prefix info to message here rather than including
it in every call to function.
* winsup.h (api_fatal): Accommodate above change.
* debug.cc (add_handle): Don't do anything if cygheap not around.
(mark_closed): Ditto.
* dll_init.cc (dll_list::detach): Fix debug output.
* fork.cc (sync_with_child): Ditto.
(vfork): Improve debug output.
* heap.cc (heap_init): Ditto.
* exceptions.cc (try_to_debug): Clarify message when debugger attaches.
Michael Haubenwallner
Corinna Vinschen
Jon Turney
Christopher Faylor