diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index 1670f7f8f..aba346b9e 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,5 +1,28 @@ +2011-05-28 Ryan Johnson + + * dll_init.cc (dll_list::find_by_modname): New function to search the + dll list for a module name only (no path). + (dll_list::alloc): Initialize newly-added members of struct dll. + (dll_list::append): New function to factor out the append operation + (used by dll_list::topsort). + (dll_list::populate_deps): New function to identify dll dependencies. + (dll_list::topsort): New function to sort the dll list topologically by + dependencies. + (dll_list::topsort_visit): New helper function for the above. + * dll_init.h (dll::ndeps): New class member. + (dll::deps): Ditto. + (dll::modname): Ditto. + (dll_list::find_by_modname): New function related to topsort. + (dll_list::populate_all_deps): Ditto. + (dll_list::populate_deps): Ditto. + (dll_list::topsort): Ditto. + (dll_list::topsort_visit): Ditto. + (dll_list::append): Ditto. + (pefile): New struct allowing simple introspection of dll images. + * fork.cc (fork): Topologically sort the dll list before forking. + 2011-05-28 Christopher Faylor - Ryan Johnson + * dll_init.c (dll_list::load_after_fork): Don't clear in_forkee here. * fork.cc (frok::errmsg): Rename from 'error'. diff --git a/winsup/cygwin/dll_init.cc b/winsup/cygwin/dll_init.cc index 68a974b7b..6fc117c0a 100644 --- a/winsup/cygwin/dll_init.cc +++ b/winsup/cygwin/dll_init.cc @@ -116,6 +116,18 @@ dll_list::operator[] (const PWCHAR name) return NULL; } +/* Look for a dll based on is short name only (no path) */ +dll * +dll_list::find_by_modname (const PWCHAR name) +{ + dll *d = &start; + while ((d = d->next) != NULL) + if (!wcscasecmp (name, d->modname)) + return d; + + return NULL; +} + #define RETRIES 1000 /* Allocate space for a dll struct. */ @@ -161,14 +173,13 @@ dll_list::alloc (HINSTANCE h, per_process *p, dll_type type) 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->type = type; - 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; - tot++; + append (d); if (type == DLL_LOAD) loaded_dlls++; } @@ -177,6 +188,119 @@ dll_list::alloc (HINSTANCE h, per_process *p, dll_type type) 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; + tot++; +} + +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)) + { + debug_printf ("%W", d->modname); + for (int i=1; i < -d->ndeps; i++) + debug_printf ("-> %W", d->deps[i-1]->modname); + + /* 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) { diff --git a/winsup/cygwin/dll_init.h b/winsup/cygwin/dll_init.h index d14cc6cb9..3a9a5c4f0 100644 --- a/winsup/cygwin/dll_init.h +++ b/winsup/cygwin/dll_init.h @@ -52,6 +52,9 @@ struct dll int count; bool has_dtors; dll_type type; + long ndeps; + dll** deps; + PWCHAR modname; WCHAR name[1]; void detach (); int init (); @@ -84,6 +87,13 @@ public: void detach (void *); void init (); void load_after_fork (HANDLE); + dll *find_by_modname (const PWCHAR name); + void populate_all_deps (); + void populate_deps (dll* d); + void topsort (); + void topsort_visit (dll* d, bool goto_tail); + void append (dll* d); + dll *inext () { while ((hold = hold->next)) @@ -109,6 +119,25 @@ public: dll_list () { protect.init ("dll_list"); } }; +/* References: + http://msdn.microsoft.com/en-us/windows/hardware/gg463125 + http://msdn.microsoft.com/en-us/library/ms809762.aspx +*/ +/* FIXME: Integrate with other similar uses in source. */ +struct pefile +{ + IMAGE_DOS_HEADER dos_hdr; + + char* rva (long offset) { return (char*) this + offset; } + PIMAGE_NT_HEADERS32 pe_hdr () { return (PIMAGE_NT_HEADERS32) rva (dos_hdr.e_lfanew); } + PIMAGE_OPTIONAL_HEADER32 optional_hdr () { return &pe_hdr ()->OptionalHeader; } + PIMAGE_DATA_DIRECTORY idata_dir (DWORD which) + { + PIMAGE_OPTIONAL_HEADER32 oh = optional_hdr (); + return (which < oh->NumberOfRvaAndSizes)? oh->DataDirectory + which : 0; + } +}; + extern dll_list dlls; void dll_global_dtors (); diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc index 3ec7fa8c5..1ac2b8a45 100644 --- a/winsup/cygwin/fork.cc +++ b/winsup/cygwin/fork.cc @@ -625,7 +625,7 @@ fork () the thread-local storage. A process forking too deeply will run into the problem to be out of temporary TLS path buffers. */ tmp_pathbuf tp; - + if (!held_everything) { if (exit_state) @@ -634,6 +634,12 @@ fork () return -1; } + /* Put the dll list in topological dependency ordering, in + hopes that the child will have a better shot at loading dlls + properly if it only has to deal with one at a time. + */ + dlls.topsort (); + ischild = !!setjmp (grouped.ch.jmp); volatile char * volatile esp;