* mmap.cc (mmap_record::access): Change argument type to caddr_t

	for strictness.
	(mprotect): Protect against calling VirtualProtect() for shared
	pages on 9x/Me.
	(fixup_mmaps_after_fork): If ReadProcessMemory() fails, try to
	change protection of parent page to PAGE_READONLY, then try again.
	Revert protection afterwards.

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index daf2b0d..67ada30 100644 (file)
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,13 @@
+2003-01-14  Corinna Vinschen <corinna@vinschen.de>
+
+       * mmap.cc (mmap_record::access): Change argument type to caddr_t
+       for strictness.
+       (mprotect): Protect against calling VirtualProtect() for shared
+       pages on 9x/Me.
+       (fixup_mmaps_after_fork): If ReadProcessMemory() fails, try to
+       change protection of parent page to PAGE_READONLY, then try again.
+       Revert protection afterwards.
+
 2003-01-14  Thomas Pfaff  <tpfaff@gmx.net>
 
        * syscalls.cc (system): Add pthread_testcancel call.

diff --git a/winsup/cygwin/mmap.cc b/winsup/cygwin/mmap.cc
index 19c8e08..4b7329c 100644 (file)
--- a/winsup/cygwin/mmap.cc
+++ b/winsup/cygwin/mmap.cc
@@ -96,7 +96,7 @@ class mmap_record
     __off64_t map_map (__off64_t off, DWORD len);
     BOOL unmap_map (caddr_t addr, DWORD len);
     void fixup_map (void);
-    int access (char *address);
+    int access (caddr_t address);
 
     fhandler_base *alloc_fh ();
     void free_fh (fhandler_base *fh);
@@ -226,7 +226,7 @@ mmap_record::fixup_map ()
 }
 
 int
-mmap_record::access (char *address)
+mmap_record::access (caddr_t address)
 {
   if (address < base_address_ || address >= base_address_ + size_to_map_)
     return 0;
@@ -889,6 +889,13 @@ mprotect (caddr_t addr, size_t len, int prot)
 
   syscall_printf ("mprotect (addr %x, len %d, prot %x)", addr, len, prot);
 
+  if (!wincap.virtual_protect_works_on_shared_pages ()
+      && addr >= (caddr_t)0x80000000 && addr <= (caddr_t)0xBFFFFFFF)
+    {
+      syscall_printf ("0 = mprotect (9x: No VirtualProtect on shared memory)");
+      return 0;
+    }
+
   if (prot == PROT_NONE)
     new_prot = PAGE_NOACCESS;
   else
@@ -948,7 +955,7 @@ fixup_mmaps_after_fork (HANDLE parent)
   for (int it = 0; it < mmapped_areas->nlists; ++it)
     {
       list *l = mmapped_areas->lists[it];
-      if (l != 0)
+      if (l)
        {
          int li;
          for (li = 0; li < l->nrecs; ++li)
@@ -978,9 +985,47 @@ fixup_mmaps_after_fork (HANDLE parent)
                        && !ReadProcessMemory (parent, address, address,
                                               getpagesize (), NULL))
                      {
-                       system_printf ("ReadProcessMemory failed for MAP_PRIVATE address %p, %E",
-                                      rec->get_address ());
-                       return -1;
+                       DWORD old_prot;
+
+                       if (GetLastError () != ERROR_PARTIAL_COPY ||
+                           !wincap.virtual_protect_works_on_shared_pages ())
+                         {
+                           system_printf ("ReadProcessMemory failed for "
+                                          "MAP_PRIVATE address %p, %E",
+                                          rec->get_address ());
+                           return -1;
+                         }
+                       if (!VirtualProtectEx (parent,
+                                              address, getpagesize (),
+                                              PAGE_READONLY, &old_prot))
+                         {
+                           system_printf ("VirtualProtectEx failed for "
+                                          "MAP_PRIVATE address %p, %E",
+                                          rec->get_address ());
+                           return -1;
+                         }
+                       else
+                         {
+                           BOOL ret, ret2;
+                           ret = ReadProcessMemory (parent, address, address,
+                                                    getpagesize (), NULL);
+                           ret2 = VirtualProtectEx(parent,
+                                                   address, getpagesize (),
+                                                   old_prot, &old_prot);
+                           if (!ret2)
+                             system_printf ("WARNING: VirtualProtectEx to"
+                                            "return to previous state "
+                                            "in parent failed for "
+                                            "MAP_PRIVATE address %p, %E",
+                                            rec->get_address ());
+                           if (!ret)
+                             {
+                               system_printf ("ReadProcessMemory FAILED for "
+                                              "MAP_PRIVATE address %p, %E",
+                                              rec->get_address ());
+                               return -1;
+                             }
+                         }
                      }
                }
              rec->fixup_map ();