CVS update by vins xemacs/src ...

[xemacs-cvs at xemacs.org]

  User: vins    
  Date: 06/11/20 19:20:23

  Branch:      xemacs/src release-21-4
  Modified:    xemacs/src fileio.c
Log:
Fix ACL problem with creating files in apparently-protected directories.

Revision  Changes    Path
1.66.2.8  +77 -0     XEmacs/xemacs/src/fileio.c

Index: fileio.c
===================================================================
RCS file: /pack/xemacscvs/XEmacs/xemacs/src/fileio.c,v
retrieving revision 1.66.2.7
retrieving revision 1.66.2.8
diff -u -p -r1.66.2.7 -r1.66.2.8
--- fileio.c	2005/01/31 02:55:14	1.66.2.7
+++ fileio.c	2006/11/20 18:20:22	1.66.2.8
@@ -57,7 +57,13 @@ Boston, MA 02111-1307, USA.  */
 #define WIN32_FILENAMES
 #ifdef WIN32_NATIVE
 #include "nt.h"
+#include <aclapi.h>
 #endif /* WIN32_NATIVE */
+#ifdef CYGWIN
+#include <w32api/aclapi.h>
+#endif
+
+
 #define IS_DRIVE(x) isalpha (x)
 /* Need to lower-case the drive letter, or else expanded
    filenames will sometimes compare inequal, because
@@ -2267,11 +2273,81 @@ check_executable (char *filename)
 #endif /* not WIN32_NATIVE */
 }
 
+
+
 /* Return nonzero if file FILENAME exists and can be written.  */
 
 static int
 check_writable (const char *filename)
 {
+#if defined(WIN32_NATIVE) || defined(CYGWIN)
+#ifdef CYGWIN
+  char filename_buffer[PATH_MAX];
+#endif
+  // Since this has to work for a directory, we can't just call 'CreateFile'
+  PSECURITY_DESCRIPTOR pDesc; /* Must be freed with LocalFree */
+  /* these need not be freed, they point into pDesc */
+  PSID psidOwner;
+  PSID psidGroup;
+  PACL pDacl;
+  PACL pSacl;
+  /* end of insides of descriptor */
+  DWORD error;
+  DWORD attributes;
+  HANDLE tokenHandle;
+  GENERIC_MAPPING genericMapping;
+  DWORD accessMask;
+  PRIVILEGE_SET PrivilegeSet;
+  DWORD dwPrivSetSize = sizeof( PRIVILEGE_SET );
+  BOOL fAccessGranted = FALSE;
+  DWORD dwAccessAllowed;
+
+#ifdef CYGWIN
+  cygwin_conv_to_full_win32_path(filename, filename_buffer);
+  filename = filename_buffer;
+#endif
+
+  /* Win32 prototype lacks const. */
+  error = GetNamedSecurityInfo((LPTSTR)filename, SE_FILE_OBJECT, 
+                               DACL_SECURITY_INFORMATION|GROUP_SECURITY_INFORMATION|OWNER_SECURITY_INFORMATION,
+                               &psidOwner, &psidGroup, &pDacl, &pSacl, &pDesc);
+  if (error != ERROR_SUCCESS) { // FAT?
+    attributes = GetFileAttributes(filename);
+    return (attributes & FILE_ATTRIBUTE_DIRECTORY) || (0 == (attributes & FILE_ATTRIBUTE_READONLY));
+  }
+
+  genericMapping.GenericRead = FILE_GENERIC_READ;
+  genericMapping.GenericWrite = FILE_GENERIC_WRITE;
+  genericMapping.GenericExecute = FILE_GENERIC_EXECUTE;
+  genericMapping.GenericAll = FILE_ALL_ACCESS;
+
+  if (!ImpersonateSelf(SecurityDelegation)) {
+    return 0;
+  }
+  if (!OpenThreadToken(GetCurrentThread(), TOKEN_ALL_ACCESS, TRUE, &tokenHandle)) {
+      return 0;
+  }
+
+  accessMask = GENERIC_WRITE;
+  MapGenericMask(&accessMask, &genericMapping);
+
+  if (!AccessCheck(pDesc, tokenHandle, accessMask, &genericMapping,
+                   &PrivilegeSet,       // receives privileges used in check
+                   &dwPrivSetSize,      // size of PrivilegeSet buffer
+                   &dwAccessAllowed,    // receives mask of allowed access rights
+                   &fAccessGranted)) 
+  {
+    DWORD oops = GetLastError();
+    CloseHandle(tokenHandle);
+    RevertToSelf();
+    LocalFree(pDesc);
+    return 0;
+  }
+  CloseHandle(tokenHandle);
+  RevertToSelf();
+  LocalFree(pDesc);
+  return fAccessGranted == TRUE;
+#else
 #ifdef HAVE_EACCESS
   return (eaccess (filename, W_OK) >= 0);
 #else
@@ -2281,6 +2357,7 @@ check_writable (const char *filename)
      Opening with O_WRONLY could work for an ordinary file,
      but would lose for directories.  */
   return (access (filename, W_OK) >= 0);
+#endif
 #endif
 }