https://bz.apache.org/bugzilla/show_bug.cgi?id=63625
--- Comment #14 from Norimasa Yamamoto <nor...@sainet.or.jp> ---
I thought a concept how to fix this issue.
(If prnsrv.exe really need to change jvm.dll's environment block.)
Before look a concept, important thing should be known.
- Where is a environment block (compiled with shared C runtime)?
compiled by MSVS 2015-2019
MODULE(exe, dll, so, ...)
_wputenv()
==> api-ms-win-crt-environment-l1-1-0.dll!_wputenv (forwarder)
==> ucrtbase.dll!_wputenv (HERE!)
compiled by MSVC 7 to 12
MODULE
_wputenv()
==> msvcrXXX.dll!_wputenv (HERE!)
(XXX is one of 70, 80, 90, 100, 110, 120 (release)
or with postfix "d" (debug))
Other compilers...
compiled by MSVC 6, MinGW w32api+GCC
held in "msvcrt.dll"
compiled by compiled by Enbarcadero/Borland C++ Builder
held in "ccYYXXXmt.dll"
compiled by Cygwin
held in "cygwin1.dll"
:
On the other hand, without shared C runtime,
every modules hold in itself.
compiled by any compiler (include MSVS 2015-2019)
MODULE (HERE! (=builtin))
_wputenv
If MODULE did not export _wputenv or similar function,
it is impossible to change from OUTER MODULEs.
If OUTER MODULEs knew its address, it may can change
but it is very danger way.
-- end of section
Because prunsrv.exe is currently static linked with C runtime,
prunsrv.exe does not depending any shared C runtime.
So jvm.dll was loaded in prunsrv.exe process, prunsrv.exe can guess
jvm.dll's C runtime by GetModuleHandle.
(If prunsrv.exe were compiled with shared C runtime,
prunsrv.exe may parse jvm.dll's Import Table in PE section,
use CreateToolhelp32Snapshot related funtions to find loaded snapshot,
... From my experience, these are hard.)
(concept code)
- before
hmodUcrt = LoadLibraryExA("ucrtbase.dll", NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
if (hmodUcrt != NULL) {
wputenv_ucrt = (WPUTENV) GetProcAddress(hmodUcrt, "_wputenv");
}
- after
// jvm.dll should be loaded at this point.
// Guess jvm.dll was compiled by known compilers.
putenv_ucrt = NULL;
if (
((hmodUcrt = GetModuleHandle("ucrtbase.dll")) != NULL) // MSVC 14.0x-14.2x
|| ((hmodUcrt = GetModuleHandle("msvcr120.dll")) != NULL) // MSVC 12.0
|| ((hmodUcrt = GetModuleHandle("msvcr110.dll")) != NULL) // MSVC 10.0
|| ((hmodUcrt = GetModuleHandle("msvcr100.dll")) != NULL) // MSVC 10.0
: (...)
|| ((hmodUcrt = GetModuleHandle("msvcrt.dll")) != NULL) // MSVC 6.0, GCC
) {
putenv_ucrt = (WPUTENV) GetProcAddress(hmodUcrt, "_wputenv");
} else {
// jvm.dll was not compiled by known compilers.
}
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