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Diffstat (limited to 'winsup/cygwin/dll_init.cc')
| -rw-r--r-- | winsup/cygwin/dll_init.cc | 722 |
1 files changed, 0 insertions, 722 deletions
diff --git a/winsup/cygwin/dll_init.cc b/winsup/cygwin/dll_init.cc deleted file mode 100644 index bd6e74a73..000000000 --- a/winsup/cygwin/dll_init.cc +++ /dev/null @@ -1,722 +0,0 @@ -/* dll_init.cc - - Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, - 2007, 2008, 2009, 2010, 2011, 2012 Red Hat, Inc. - -This software is a copyrighted work licensed under the terms of the -Cygwin license. Please consult the file "CYGWIN_LICENSE" for -details. */ - -#include "winsup.h" -#include "cygerrno.h" -#include "perprocess.h" -#include "sync.h" -#include "dll_init.h" -#include "environ.h" -#include "security.h" -#include "path.h" -#include "fhandler.h" -#include "dtable.h" -#include "cygheap.h" -#include "pinfo.h" -#include "child_info.h" -#include "cygtls.h" -#include "exception.h" -#include <wchar.h> -#include <sys/reent.h> -#include <assert.h> - -extern void __stdcall check_sanity_and_sync (per_process *); - -#define fabort fork_info->abort - -dll_list dlls; - -muto dll_list::protect; - -static bool dll_global_dtors_recorded; - -/* Run destructors for all DLLs on exit. */ -void -dll_global_dtors () -{ - /* Don't attempt to call destructors if we're still in fork processing - since that likely means fork is failing and everything will not have been - set up. */ - if (in_forkee) - return; - int recorded = dll_global_dtors_recorded; - dll_global_dtors_recorded = false; - if (recorded && dlls.start.next) - for (dll *d = dlls.end; d != &dlls.start; d = d->prev) - d->run_dtors (); -} - -/* Run all constructors associated with a dll */ -void -per_module::run_ctors () -{ - void (**pfunc)() = ctors; - - /* Run ctors backwards, so skip the first entry and find how many - there are, then run them. */ - - if (pfunc) - { - int i; - for (i = 1; pfunc[i]; i++); - - for (int j = i - 1; j > 0; j--) - (pfunc[j]) (); - } -} - -/* Run all destructors associated with a dll */ -void -per_module::run_dtors () -{ - void (**pfunc)() = dtors; - while (*++pfunc) - (*pfunc) (); -} - -/* Initialize an individual DLL */ -int -dll::init () -{ - int ret = 1; - - /* This should be a no-op. Why didn't we just import this variable? */ - if (!p.envptr) - p.envptr = &__cygwin_environ; - else if (*(p.envptr) != __cygwin_environ) - *(p.envptr) = __cygwin_environ; - - /* Don't run constructors or the "main" if we've forked. */ - if (!in_forkee) - { - /* global contructors */ - p.run_ctors (); - - /* entry point of dll (use main of per_process with null args...) */ - if (p.main) - ret = p.main (0, 0, 0); - } - - 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. */ -dll * -dll_list::operator[] (const PWCHAR name) -{ - dll *d = &start; - while ((d = d->next) != NULL) - if (!wcscasecmp (name, d->name)) - return d; - - return NULL; -} - -/* Look for a dll based on the basename. */ -dll * -dll_list::find_by_modname (const PWCHAR modname) -{ - dll *d = &start; - while ((d = d->next) != NULL) - if (!wcscasecmp (modname, d->modname)) - return d; - - return NULL; -} - -#define RETRIES 1000 - -/* Allocate space for a dll struct. */ -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; - - 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]; - 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); - d->p = p; - } - else - { - /* 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. */ - 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->image_size = ((pefile*)h)->optional_hdr ()->SizeOfImage; - d->preferred_base = (void*) ((pefile*)h)->optional_hdr()->ImageBase; - d->type = type; - append (d); - if (type == DLL_LOAD) - loaded_dlls++; - } - guard (false); - assert (p->envptr != NULL); - return d; -} - -void -dll_list::append (dll* d) -{ - if (end == NULL) - end = &start; /* Point to "end" of dll chain. */ - end->next = d; /* Standard linked list stuff. */ - d->next = NULL; - d->prev = end; - end = d; -} - -void dll_list::populate_deps (dll* d) -{ - WCHAR wmodname[NT_MAX_PATH]; - pefile* pef = (pefile*) d->handle; - PIMAGE_DATA_DIRECTORY dd = pef->idata_dir (IMAGE_DIRECTORY_ENTRY_IMPORT); - /* Annoyance: calling crealloc with a NULL pointer will use the - wrong heap and crash, so we have to replicate some code */ - long maxdeps = 4; - d->deps = (dll**) cmalloc (HEAP_2_DLL, maxdeps*sizeof (dll*)); - d->ndeps = 0; - for (PIMAGE_IMPORT_DESCRIPTOR id= - (PIMAGE_IMPORT_DESCRIPTOR) pef->rva (dd->VirtualAddress); - dd->Size && id->Name; - id++) - { - char* modname = pef->rva (id->Name); - sys_mbstowcs (wmodname, NT_MAX_PATH, modname); - if (dll* dep = find_by_modname (wmodname)) - { - if (d->ndeps >= maxdeps) - { - maxdeps = 2*(1+maxdeps); - d->deps = (dll**) crealloc (d->deps, maxdeps*sizeof (dll*)); - } - d->deps[d->ndeps++] = dep; - } - } - - /* add one to differentiate no deps from unknown */ - d->ndeps++; -} - - -void -dll_list::topsort () -{ - /* Anything to do? */ - if (!end) - return; - - /* make sure we have all the deps available */ - dll* d = &start; - while ((d = d->next)) - if (!d->ndeps) - populate_deps (d); - - /* unlink head and tail pointers so the sort can rebuild the list */ - d = start.next; - start.next = end = NULL; - topsort_visit (d, true); - - /* clear node markings made by the sort */ - d = &start; - while ((d = d->next)) - { -#ifdef DEBUGGING - paranoid_printf ("%W", d->modname); - for (int i = 1; i < -d->ndeps; i++) - paranoid_printf ("-> %W", d->deps[i - 1]->modname); -#endif - - /* It would be really nice to be able to keep this information - around for next time, but we don't have an easy way to - invalidate cached dependencies when a module unloads. */ - d->ndeps = 0; - cfree (d->deps); - d->deps = NULL; - } -} - -/* A recursive in-place topological sort. The result is ordered so that - dependencies of a dll appear before it in the list. - - NOTE: this algorithm is guaranteed to terminate with a "partial - order" of dlls but does not do anything smart about cycles: an - arbitrary dependent dll will necessarily appear first. Perhaps not - surprisingly, Windows ships several dlls containing dependency - cycles, including SspiCli/RPCRT4.dll and a lovely tangle involving - USP10/LPK/GDI32/USER32.dll). Fortunately, we don't care about - Windows DLLs here, and cygwin dlls should behave better */ -void -dll_list::topsort_visit (dll* d, bool seek_tail) -{ - /* Recurse to the end of the dll chain, then visit nodes as we - unwind. We do this because once we start visiting nodes we can no - longer trust any _next_ pointers. - - We "mark" visited nodes (to avoid revisiting them) by negating - ndeps (undone once the sort completes). */ - if (seek_tail && d->next) - topsort_visit (d->next, true); - - if (d->ndeps > 0) - { - d->ndeps = -d->ndeps; - for (long i = 1; i < -d->ndeps; i++) - topsort_visit (d->deps[i - 1], false); - - append (d); - } -} - - -dll * -dll_list::find (void *retaddr) -{ - MEMORY_BASIC_INFORMATION m; - if (!VirtualQuery (retaddr, &m, sizeof m)) - return NULL; - HMODULE h = (HMODULE) m.AllocationBase; - - dll *d = &start; - while ((d = d->next)) - if (d->handle == h) - break; - return d; -} - -/* Detach a DLL from the chain. */ -void -dll_list::detach (void *retaddr) -{ - dll *d; - /* Don't attempt to call destructors if we're still in fork processing - since that likely means fork is failing and everything will not have been - set up. */ - if (!myself || in_forkee) - return; - guard (true); - if ((d = find (retaddr))) - { - if (d->count <= 0) - system_printf ("WARNING: trying to detach an already detached dll ..."); - if (--d->count == 0) - { - /* Ensure our exception handler is enabled for destructors */ - exception protect; - /* Call finalize function if we are not already exiting */ - if (!exit_state) - __cxa_finalize (d); - d->run_dtors (); - d->prev->next = d->next; - if (d->next) - d->next->prev = d->prev; - if (d->type == DLL_LOAD) - loaded_dlls--; - if (end == d) - end = d->prev; - cfree (d); - } - } - guard (false); -} - -/* Initialization for all linked DLLs, called by dll_crt0_1. */ -void -dll_list::init () -{ - /* Walk the dll chain, initializing each dll */ - dll *d = &start; - dll_global_dtors_recorded = d->next != NULL; - while ((d = d->next)) - d->init (); -} - -#define A64K (64 * 1024) - - -/* Reserve the chunk of free address space starting _here_ and (usually) - covering at least _dll_size_ bytes. However, we must take care not - to clobber the dll's target address range because it often overlaps. - */ -static DWORD -reserve_at (const PWCHAR name, DWORD here, DWORD dll_base, DWORD dll_size) -{ - DWORD size; - MEMORY_BASIC_INFORMATION mb; - - if (!VirtualQuery ((void *) here, &mb, sizeof (mb))) - fabort ("couldn't examine memory at %08lx while mapping %W, %E", - here, name); - if (mb.State != MEM_FREE) - return 0; - - size = mb.RegionSize; - - // don't clobber the space where we want the dll to land - DWORD end = here + size; - DWORD dll_end = dll_base + dll_size; - if (dll_base < here && dll_end > here) - here = dll_end; // the dll straddles our left edge - else if (dll_base >= here && dll_base < end) - end = dll_base; // the dll overlaps partly or fully to our right - - size = end - here; - if (!VirtualAlloc ((void *) here, size, MEM_RESERVE, PAGE_NOACCESS)) - fabort ("couldn't allocate memory %p(%d) for '%W' alignment, %E\n", - here, size, name); - return here; -} - -/* Release the memory previously allocated by "reserve_at" above. */ -static void -release_at (const PWCHAR name, DWORD here) -{ - if (!VirtualFree ((void *) here, 0, MEM_RELEASE)) - fabort ("couldn't release memory %p for '%W' alignment, %E\n", - here, name); -} - -/* Step 1: Reserve memory for all DLL_LOAD dlls. This is to prevent - anything else from taking their spot as we compensate for Windows - randomly relocating things. - - NOTE: because we can't depend on LoadLibraryExW to do the right - thing, we have to do a vanilla VirtualAlloc instead. One possible - optimization might attempt a LoadLibraryExW first, in case it lands - in the right place, but then we have to find a way of tracking - which dlls ended up needing VirtualAlloc after all. */ -void -dll_list::reserve_space () -{ - for (dll* d = dlls.istart (DLL_LOAD); d; d = dlls.inext ()) - if (!VirtualAlloc (d->handle, d->image_size, MEM_RESERVE, PAGE_NOACCESS)) - fabort ("address space needed by '%W' (%p) is already occupied", - 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. */ -void -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; -void dll_list::load_after_fork_impl (HANDLE parent, dll* d, int retries) -{ - /* Step 2: For each dll which did not map at its preferred base - address in the parent, try to coerce it to land at the same spot - as before. If not, unload it, reserve the memory around it, and - try again. Use recursion to remember blocked regions address - space so we can release them later. - - We DONT_RESOLVE_DLL_REFERENCES at first in case the DLL lands in - the wrong spot; - - NOTE: This step skips DLLs which loaded at their preferred - address in the parent because they should behave (we already - verified that their preferred address in the child is - available). However, this may fail on a Vista/Win7 machine with - ASLR active, because the ASLR base address will usually not equal - the preferred base recorded in the dll. In this case, we should - make the LoadLibraryExW call unconditional. - */ - for ( ; d; d = dlls.inext ()) - if (d->handle != d->preferred_base) - { - /* See if the DLL will load in proper place. If not, unload it, - reserve the memory around it, and try again. - - If this is the first attempt, we need to release the - dll's protective reservation from step 1 - */ - if (!retries && !VirtualFree (d->handle, 0, MEM_RELEASE)) - fabort ("unable to release protective reservation for %W (%08lx), %E", - d->modname, d->handle); - - HMODULE h = LoadLibraryExW (d->name, NULL, DONT_RESOLVE_DLL_REFERENCES); - if (!h) - fabort ("unable to create interim mapping for %W, %E", d->name); - if (h != d->handle) - { - sigproc_printf ("%W loaded in wrong place: %08lx != %08lx", - d->modname, h, d->handle); - FreeLibrary (h); - DWORD reservation = reserve_at (d->modname, (DWORD) h, - (DWORD) d->handle, d->image_size); - if (!reservation) - fabort ("unable to block off %p to prevent %W from loading there", - h, d->modname); - - if (retries < DLL_RETRY_MAX) - load_after_fork_impl (parent, d, retries+1); - else - fabort ("unable to remap %W to same address as parent (%08lx) - try running rebaseall", - d->modname, d->handle); - - /* once the above returns all the dlls are mapped; release - the reservation and continue unwinding */ - sigproc_printf ("releasing blocked space at %08lx", reservation); - release_at (d->modname, reservation); - return; - } - } - - /* Step 3: try to load each dll for real after either releasing the - protective reservation (for well-behaved dlls) or unloading the - interim mapping (for rebased dlls) . The dll list is sorted in - dependency order, so we shouldn't pull in any additional dlls - outside our control. */ - for (dll *d = dlls.istart (DLL_LOAD); d; d = dlls.inext ()) - { - if (d->handle == d->preferred_base) - { - if (!VirtualFree (d->handle, 0, MEM_RELEASE)) - fabort ("unable to release protective reservation for %W (%08lx), %E", - d->modname, d->handle); - } - else - { - /* Free the library using our parent's handle: it's identical - to ours or we wouldn't have gotten this far */ - if (!FreeLibrary (d->handle)) - fabort ("unable to unload interim mapping of %W, %E", - d->modname); - } - HMODULE h = LoadLibraryW (d->name); - if (!h) - fabort ("unable to map %W, %E", d->name); - if (h != d->handle) - fabort ("unable to map %W to same address as parent: %p != %p", - d->modname, d->handle, h); - } -} - -struct dllcrt0_info -{ - HMODULE h; - per_process *p; - int res; - dllcrt0_info (HMODULE h0, per_process *p0): h (h0), p (p0) {} -}; - -extern "C" int -dll_dllcrt0 (HMODULE h, per_process *p) -{ - if (dynamically_loaded) - return 1; - dllcrt0_info x (h, p); - dll_dllcrt0_1 (&x); - return x.res; -} - -void -dll_dllcrt0_1 (VOID *x) -{ - HMODULE& h = ((dllcrt0_info *) x)->h; - per_process*& p = ((dllcrt0_info *) x)->p; - int& res = ((dllcrt0_info *) x)->res; - - if (p == NULL) - p = &__cygwin_user_data; - else - { - *(p->impure_ptr_ptr) = __cygwin_user_data.impure_ptr; - _pei386_runtime_relocator (p); - } - - bool linked = !cygwin_finished_initializing && !in_load_after_fork; - - /* 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, - when loaded either statically or dynamically. Because this leaves - a stale pointer into demapped memory space if the DLL is unloaded - by a call to dlclose, we prevent this happening for dynamically - loaded DLLS in dlopen by saving and restoring cxx_malloc around - the call to LoadLibrary, which invokes the DLL's startup sequence. - Modern DLLs won't even attempt to override the pointer when loaded - statically, but will write their overrides directly into the - struct it points to. With all modern DLLs, this will remain the - default_cygwin_cxx_malloc struct in cxx.cc, but if any broken DLLs - are in the mix they will have overridden the pointer and subsequent - overrides will go into their embedded cxx_malloc structs. This is - almost certainly not a problem as they can never be unloaded, but - if we ever did want to do anything about it, we could check here to - see if the pointer had been altered in the early parts of the DLL's - startup, and if so copy back the new overrides and reset it here. - However, that's just a note for the record; at the moment, we can't - see any need to worry about this happening. */ - - check_sanity_and_sync (p); - - dll_type type; - - /* If this function is called before cygwin has finished - initializing, then the DLL must be a cygwin-aware DLL - that was explicitly linked into the program rather than - a dlopened DLL. */ - if (linked) - type = DLL_LINK; - else - { - type = DLL_LOAD; - dlls.reload_on_fork = 1; - } - - /* Allocate and initialize space for the DLL. */ - dll *d = dlls.alloc (h, p, type); - - /* If d == NULL, then something is broken. - Otherwise, if we've finished initializing, it's ok to - initialize the DLL. If we haven't finished initializing, - it may not be safe to call the dll's "main" since not - all of cygwin's internal structures may have been set up. */ - if (!d || (!linked && !d->init ())) - res = -1; - else - res = (DWORD) d; -} - -/* OBSOLETE: This function is obsolete and will go away in the - future. Cygwin can now handle being loaded from a noncygwin app - using the same entry point. */ - -extern "C" int -dll_noncygwin_dllcrt0 (HMODULE h, per_process *p) -{ - return dll_dllcrt0 (h, p); -} - -extern "C" void -cygwin_detach_dll (dll *) -{ - HANDLE retaddr; - if (_my_tls.isinitialized ()) - retaddr = (void *) _my_tls.retaddr (); - else - retaddr = __builtin_return_address (0); - dlls.detach (retaddr); -} - -extern "C" void -dlfork (int val) -{ - dlls.reload_on_fork = val; -} - -/* Called from various places to update all of the individual - ideas of the environ block. Explain to me again why we didn't - just import __cygwin_environ? */ -void __stdcall -update_envptrs () -{ - for (dll *d = dlls.istart (DLL_ANY); d; d = dlls.inext ()) - if (*(d->p.envptr) != __cygwin_environ) - *(d->p.envptr) = __cygwin_environ; - *main_environ = __cygwin_environ; -} |