* 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.
This commit is contained in:
Christopher Faylor 2011-05-28 20:17:09 +00:00
parent 8551087823
commit a92339ab63
4 changed files with 191 additions and 9 deletions

View File

@ -1,5 +1,28 @@
2011-05-28 Ryan Johnson <ryan.johnson@cs.utoronto.ca>
* 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 <me.cygwin2011@cgf.cx>
Ryan Johnson <ryan.johnson@cs.utoronto.ca>
* dll_init.c (dll_list::load_after_fork): Don't clear in_forkee here.
* fork.cc (frok::errmsg): Rename from 'error'.

View File

@ -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)
{

View File

@ -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 ();

View File

@ -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;