[newlib-cygwin/cygwin-3_4-branch] Cygwin: open_shared: don't reuse shared_locations parameter as output

Corinna Vinschen corinna@sourceware.org
Tue Jan 17 19:15:24 GMT 2023


https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=62f11a5a57043404719cc5d81f3d2ebbf8142b29

commit 62f11a5a57043404719cc5d81f3d2ebbf8142b29
Author:     Corinna Vinschen <corinna@vinschen.de>
AuthorDate: Mon Jan 16 22:25:42 2023 +0100
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Tue Jan 17 19:47:33 2023 +0100

    Cygwin: open_shared: don't reuse shared_locations parameter as output
    
    For ages, open_shared uses the shared_locations parameter as
    output to indicate if the mapping for a shared region has been
    created or just opened.  Split this into two parameters.  Use
    the shared_locations parameter as input only, return the creation
    state of the mapping in a bool reference parameter.
    
    Conflict: Simple collision due to missing backport of
              3721a756b0d8 ("Cygwin: console: Make the console accessible from other terminals.")
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/fhandler/console.cc          |  7 +++---
 winsup/cygwin/local_includes/shared_info.h |  8 +++---
 winsup/cygwin/mm/shared.cc                 | 39 ++++++++++++++++--------------
 winsup/cygwin/pinfo.cc                     |  6 ++---
 4 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/winsup/cygwin/fhandler/console.cc b/winsup/cygwin/fhandler/console.cc
index bfcdb84b351d..a30b5416e22a 100644
--- a/winsup/cygwin/fhandler/console.cc
+++ b/winsup/cygwin/fhandler/console.cc
@@ -148,15 +148,14 @@ beep ()
 }
 
 fhandler_console::console_state *
-fhandler_console::open_shared_console (HWND hw, HANDLE& h, bool& create)
+fhandler_console::open_shared_console (HWND hw, HANDLE& h, bool& created)
 {
   wchar_t namebuf[(sizeof "XXXXXXXXXXXXXXXXXX-consNNNNNNNNNN")];
   __small_swprintf (namebuf, L"%S-cons%p", &cygheap->installation_key, hw);
 
-  shared_locations m = create ? SH_SHARED_CONSOLE : SH_JUSTOPEN;
+  shared_locations m = created ? SH_SHARED_CONSOLE : SH_JUSTOPEN;
   console_state *res = (console_state *)
-    open_shared (namebuf, 0, h, sizeof (*shared_console_info), &m);
-  create = m != SH_JUSTOPEN;
+    open_shared (namebuf, 0, h, sizeof (*shared_console_info), m, created);
   return res;
 }
 
diff --git a/winsup/cygwin/local_includes/shared_info.h b/winsup/cygwin/local_includes/shared_info.h
index 6c53ec0b8b0f..cbe55a27887b 100644
--- a/winsup/cygwin/local_includes/shared_info.h
+++ b/winsup/cygwin/local_includes/shared_info.h
@@ -89,9 +89,9 @@ HANDLE get_session_parent_dir ();
 char *shared_name (char *, const char *, int);
 WCHAR *shared_name (WCHAR *, const WCHAR *, int);
 void *open_shared (const WCHAR *, int, HANDLE&, DWORD,
-			     shared_locations, PSECURITY_ATTRIBUTES = &sec_all,
-			     DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
+		   shared_locations, PSECURITY_ATTRIBUTES = &sec_all,
+		   DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
 void *open_shared (const WCHAR *, int, HANDLE&, DWORD,
-			     shared_locations *, PSECURITY_ATTRIBUTES = &sec_all,
-			     DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
+		   shared_locations, bool &, PSECURITY_ATTRIBUTES = &sec_all,
+		   DWORD = FILE_MAP_READ | FILE_MAP_WRITE);
 extern void user_shared_create (bool reinit);
diff --git a/winsup/cygwin/mm/shared.cc b/winsup/cygwin/mm/shared.cc
index 893b20d289b4..351d314af01b 100644
--- a/winsup/cygwin/mm/shared.cc
+++ b/winsup/cygwin/mm/shared.cc
@@ -127,54 +127,57 @@ void *
 open_shared (const WCHAR *name, int n, HANDLE& shared_h, DWORD size,
 	     shared_locations m, PSECURITY_ATTRIBUTES psa, DWORD access)
 {
-  return open_shared (name, n, shared_h, size, &m, psa, access);
+  bool created_dummy;
+  return open_shared (name, n, shared_h, size, m, created_dummy, psa, access);
 }
 
 void *
 open_shared (const WCHAR *name, int n, HANDLE& shared_h, DWORD size,
-	     shared_locations *m, PSECURITY_ATTRIBUTES psa, DWORD access)
+	     shared_locations m, bool &created, PSECURITY_ATTRIBUTES psa,
+	     DWORD access)
 {
+  WCHAR map_buf[MAX_PATH];
+  WCHAR *mapname = NULL;
   void *shared;
-
   void *addr;
-  if (*m == SH_JUSTCREATE || *m == SH_JUSTOPEN)
+
+  if (m == SH_JUSTCREATE || m == SH_JUSTOPEN)
     addr = NULL;
   else
-    addr = (void *) region_address[*m];
+    addr = (void *) region_address[m];
 
-  WCHAR map_buf[MAX_PATH];
-  WCHAR *mapname = NULL;
-
-  if (shared_h)
-    *m = SH_JUSTOPEN;
-  else
+  created = false;
+  if (!shared_h)
     {
       if (name)
 	mapname = shared_name (map_buf, name, n);
-      if (*m == SH_JUSTOPEN)
-	shared_h = OpenFileMappingW (access, FALSE, mapname);
+      if (m == SH_JUSTOPEN)
+	shared_h = OpenFileMappingW (FILE_MAP_READ | FILE_MAP_WRITE, FALSE,
+				     mapname);
       else
 	{
+	  created = true;
 	  shared_h = CreateFileMappingW (INVALID_HANDLE_VALUE, psa,
 					PAGE_READWRITE, 0, size, mapname);
 	  if (GetLastError () == ERROR_ALREADY_EXISTS)
-	    *m = SH_JUSTOPEN;
+	    created = false;
 	}
       if (shared_h)
 	/* ok! */;
-      else if (*m != SH_JUSTOPEN)
+      else if (m != SH_JUSTOPEN)
 	api_fatal ("CreateFileMapping %W, %E.  Terminating.", mapname);
       else
 	return NULL;
     }
 
-  shared = (shared_info *) MapViewOfFileEx (shared_h, access, 0, 0, 0, addr);
+  shared = MapViewOfFileEx (shared_h, FILE_MAP_READ | FILE_MAP_WRITE,
+			    0, 0, 0, addr);
 
   if (!shared)
     api_fatal ("MapViewOfFileEx '%W'(%p), %E.  Terminating.", mapname, shared_h);
 
-  debug_printf ("name %W, n %d, shared %p (wanted %p), h %p, *m %d",
-		mapname, n, shared, addr, shared_h, *m);
+  debug_printf ("name %W, n %d, shared %p (wanted %p), h %p, m %d",
+		mapname, n, shared, addr, shared_h, m);
 
   return shared;
 }
diff --git a/winsup/cygwin/pinfo.cc b/winsup/cygwin/pinfo.cc
index e086ab9a8454..8dc46eead7e7 100644
--- a/winsup/cygwin/pinfo.cc
+++ b/winsup/cygwin/pinfo.cc
@@ -387,8 +387,10 @@ pinfo::init (pid_t n, DWORD flag, HANDLE h0)
 
   for (int i = 0; i < 20; i++)
     {
+      bool created;
+
       procinfo = (_pinfo *) open_shared (L"cygpid", n, h0, sizeof (_pinfo),
-					 &shloc, sec_attribs, access);
+					 shloc, created, sec_attribs, access);
       if (!h0)
 	{
 	  if (createit)
@@ -409,8 +411,6 @@ pinfo::init (pid_t n, DWORD flag, HANDLE h0)
 	  continue;
 	}
 
-      bool created = shloc != SH_JUSTOPEN;
-
       /* Just fetching info for ps or /proc, don't do anything rash. */
       if (!created && !(flag & PID_NEW) && !procinfo->ppid
 	  && (flag & PID_PROCINFO))


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