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author | Christopher Faylor <me@cgf.cx> | 2011-05-28 20:17:09 +0000 |
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committer | Christopher Faylor <me@cgf.cx> | 2011-05-28 20:17:09 +0000 |
commit | a92339ab635febf6ce9873fecca6f3d113dbb3b5 (patch) | |
tree | d0fba808521f5ad5806afdaa0f1660a2407e6768 /winsup/cygwin/dll_init.cc | |
parent | 855108782321cee83378b069fe89343f191ba28c (diff) | |
download | cygnal-a92339ab635febf6ce9873fecca6f3d113dbb3b5.tar.gz cygnal-a92339ab635febf6ce9873fecca6f3d113dbb3b5.tar.bz2 cygnal-a92339ab635febf6ce9873fecca6f3d113dbb3b5.zip |
* 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.
Diffstat (limited to 'winsup/cygwin/dll_init.cc')
-rw-r--r-- | winsup/cygwin/dll_init.cc | 138 |
1 files changed, 131 insertions, 7 deletions
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) { |