diff options
Diffstat (limited to 'winsup/cygwin/dll_init.cc')
| -rw-r--r-- | winsup/cygwin/dll_init.cc | 126 |
1 files changed, 32 insertions, 94 deletions
diff --git a/winsup/cygwin/dll_init.cc b/winsup/cygwin/dll_init.cc index 420f0d8f2..8a72ecee6 100644 --- a/winsup/cygwin/dll_init.cc +++ b/winsup/cygwin/dll_init.cc @@ -1,7 +1,7 @@ /* dll_init.cc Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, - 2007, 2008, 2009, 2010, 2011, 2012 Red Hat, Inc. + 2007, 2008, 2009, 2010, 2011 Red Hat, Inc. This software is a copyrighted work licensed under the terms of the Cygwin license. Please consult the file "CYGWIN_LICENSE" for @@ -106,47 +106,7 @@ dll::init () return ret; } -/* Look for a dll based on the full path. - - CV, 2012-03-04: Per MSDN, If a DLL with the same module name is already - loaded in memory, the system uses the loaded DLL, no matter which directory - it is in. The system does not search for the DLL. See - http://msdn.microsoft.com/en-us/library/ms682586%28v=vs.85%29.aspx - - On 2012-02-08 I interpreted "module name" as "basename". So the assumption - was that the Windows Loader does not load another DLL with the same basename, - if one such DLL is already loaded. Consequentially I changed the code so - that DLLs are only compared by basename. - - This assumption was obviously wrong, as the perl dynaloader proves. It - loads multiple DLLs with the same basename into memory, just from different - locations. This mechanism is broken when only comparing basenames in the - below code. - - However, the original problem reported on 2012-02-07 was a result of - a subtil difference between the paths returned by different calls to - GetModuleFileNameW: Sometimes the path is a plain DOS path, sometimes - it's preceeded by the long pathname prefix "\\?\". - - So I reverted the original change from 2012-02-08 and only applied the - following fix: Check if the path is preceeded by a long pathname prefix, - and, if so, drop it forthwith so that subsequent full path comparisons - work as expected. - - At least that was the original idea. In fact there are two case, linked - and runtime loaded DLLs, which have to be distinguished: - - - Linked DLLs are loaded by only specifying the basename of the DLL and - searching it using the system DLL search order as given in the - aforementioned MSDN URL. - - - Runtime loaded DLLs are specified with the full path since that's how - dlopen works. - - In effect, we have to be careful not to mix linked and loaded DLLs. - For more info how this gets accomplished, see the comments at the start - of dll_list::alloc, as well as the comment preceeding the definition of - the in_load_after_fork bool later in the file. */ +/* Look for a dll based on name */ dll * dll_list::operator[] (const PWCHAR name) { @@ -158,13 +118,13 @@ dll_list::operator[] (const PWCHAR name) return NULL; } -/* Look for a dll based on the basename. */ +/* Look for a dll based on is short name only (no path) */ dll * -dll_list::find_by_modname (const PWCHAR modname) +dll_list::find_by_modname (const PWCHAR name) { dll *d = &start; while ((d = d->next) != NULL) - if (!wcscasecmp (modname, d->modname)) + if (!wcscasecmp (name, d->modname)) return d; return NULL; @@ -176,48 +136,31 @@ dll_list::find_by_modname (const PWCHAR modname) dll * dll_list::alloc (HINSTANCE h, per_process *p, dll_type type) { - WCHAR buf[NT_MAX_PATH]; - GetModuleFileNameW (h, buf, sizeof (buf)); - PWCHAR name = buf; - if (!wcsncmp (name, L"\\\\?\\", 4)) - { - name += 4; - if (!wcsncmp (name, L"UNC\\", 4)) - { - name += 2; - *name = L'\\'; - } - } - DWORD namelen = wcslen (name); - PWCHAR modname = wcsrchr (name, L'\\') + 1; + WCHAR name[NT_MAX_PATH]; + DWORD namelen = GetModuleFileNameW (h, name, sizeof (name)); guard (true); - /* Already loaded? For linked DLLs, only compare the basenames. Linked - DLLs are loaded using just the basename and the default DLL search path. - The Windows loader picks up the first one it finds. */ - dll *d = (type == DLL_LINK) ? dlls.find_by_modname (modname) : dlls[name]; + /* Already loaded? */ + dll *d = dlls[name]; if (d) { if (!in_forkee) d->count++; /* Yes. Bump the usage count. */ - else if (d->handle != h) - fabort ("%W: Loaded to different address: parent(%p) != child(%p)", - name, d->handle, h); - /* If this DLL has been linked against, and the full path differs, try - to sanity check if this is the same DLL, just in another path. */ - else if (type == DLL_LINK && wcscasecmp (name, d->name) - && (d->p.data_start != p->data_start - || d->p.data_start != p->data_start - || d->p.bss_start != p->bss_start - || d->p.bss_end != p->bss_end - || d->p.ctors != p->ctors - || d->p.dtors != p->dtors)) - fabort ("\nLoaded different DLL with same basename in forked child,\n" - "parent loaded: %W\n" - " child loaded: %W\n" - "The DLLs differ, so it's not safe to run the forked child.\n" - "Make sure to remove the offending DLL before trying again.", - d->name, name); + else + { + if (d->p.data_start != p->data_start) + fabort ("data segment start: parent(%p) != child(%p)", + d->p.data_start, p->data_start); + else if (d->p.data_end != p->data_end) + fabort ("data segment end: parent(%p) != child(%p)", + d->p.data_end, p->data_end); + else if (d->p.bss_start != p->bss_start) + fabort ("data segment start: parent(%p) != child(%p)", + d->p.bss_start, p->bss_start); + else if (d->p.bss_end != p->bss_end) + fabort ("bss segment end: parent(%p) != child(%p)", + d->p.bss_end, p->bss_end); + } d->p = p; } else @@ -225,16 +168,18 @@ dll_list::alloc (HINSTANCE h, per_process *p, dll_type type) /* FIXME: Change this to new at some point. */ d = (dll *) cmalloc (HEAP_2_DLL, sizeof (*d) + (namelen * sizeof (*name))); - /* Now we've allocated a block of information. Fill it in with the - supplied info about this DLL. */ + /* Now we've allocated a block of information. Fill it in with the supplied + info about this DLL. */ d->count = 1; wcscpy (d->name, name); - d->modname = d->name + (modname - name); d->handle = h; d->has_dtors = true; d->p = p; d->ndeps = 0; d->deps = NULL; + d->modname = wcsrchr (d->name, L'\\'); + if (d->modname) + d->modname++; d->image_size = ((pefile*)h)->optional_hdr ()->SizeOfImage; d->preferred_base = (void*) ((pefile*)h)->optional_hdr()->ImageBase; d->type = type; @@ -486,12 +431,6 @@ dll_list::reserve_space () d->modname, d->handle); } -/* We need the in_load_after_fork flag so dll_dllcrt0_1 can decide at fork - time if this is a linked DLL or a dynamically loaded DLL. In either case, - both, cygwin_finished_initializing and in_forkee are true, so they are not - sufficient to discern the situation. */ -static bool NO_COPY in_load_after_fork; - /* Reload DLLs after a fork. Iterates over the list of dynamically loaded DLLs and attempts to load them in the same place as they were loaded in the parent. */ @@ -501,9 +440,7 @@ dll_list::load_after_fork (HANDLE parent) // moved to frok::child for performance reasons: // dll_list::reserve_space(); - in_load_after_fork = true; load_after_fork_impl (parent, dlls.istart (DLL_LOAD), 0); - in_load_after_fork = false; } static int const DLL_RETRY_MAX = 6; @@ -541,7 +478,8 @@ void dll_list::load_after_fork_impl (HANDLE parent, dll* d, int retries) HMODULE h = LoadLibraryExW (d->name, NULL, DONT_RESOLVE_DLL_REFERENCES); if (!h) - fabort ("unable to create interim mapping for %W, %E", d->name); + fabort ("unable to create interim mapping for %W, %E", + d->name); if (h != d->handle) { sigproc_printf ("%W loaded in wrong place: %08lx != %08lx", @@ -630,7 +568,7 @@ dll_dllcrt0_1 (VOID *x) _pei386_runtime_relocator (p); } - bool linked = !cygwin_finished_initializing && !in_load_after_fork; + bool linked = !in_forkee && !cygwin_finished_initializing; /* Broken DLLs built against Cygwin versions 1.7.0-49 up to 1.7.0-57 override the cxx_malloc pointer in their DLL initialization code, |