[mapserver-users] Oddball mapserver/ArcSDE issue

[Russell McOrmond]

On Tue, 16 Mar 2010, Russell McOrmond wrote:

>  The segmentation fault is caused by using a string which is actually null 
> being returned from string functions, with the null then being used as if it 
> were a string.
>  See: http://trac.osgeo.org/mapserver/ticket/2988  "Check error returns from 
> mapstring functions."

   Sorry to be responding to my own messages, but wanted to report on 
progress.


   I added in some additional error return checking, and put some 
suggestions into the bug listed above.

   I created some additional error reporting on what the reason for the 
iconv() failure was (see path at end of message), and now I see "An 
invalid multibyte sequence has been encountered in the input" in the 
MS_ERRORFILE.

   While it is great to have mapserver not core dumping, I am still 
wondering if anyone has ideas of where to go next.  I suspect there is 
something invalid in the data that is causing ArcSDE to send me strings 
that aren't valid UTF-16 characters.  I don't know enough about ArcSDE or 
other ESRI software to know how to validate such things.



Note: Please consider patches like the one below and/or the ones in the 
bug for future releases of mapserver.  It would be great if Mapserver 
would output error messages rather than core dump.


--- mapstring.c-orig    2010-03-17 16:43:19.000000000 -0400
+++ mapstring.c 2010-03-18 11:54:02.000000000 -0400
@@ -1504,8 +1504,8 @@
  char* msConvertWideStringToUTF8 (const wchar_t* string, const char* 
encoding) {
  #ifdef USE_ICONV

-    int bconvFailed = MS_TRUE;
      char* output = NULL;
+    char* errormessage = NULL;
      iconv_t cd = NULL;
      size_t nStr;
      size_t nInSize;
@@ -1540,23 +1540,36 @@
             pszUTF8 = output;
             pwszWide = string;
             nConv = iconv(cd, (char **)&pwszWide, &nInSize, &pszUTF8, 
&nOutSize);
-           if ((size_t)-1 != nConv &&  nOutSize != nBufferSize)
-               bconvFailed = MS_FALSE;
+           if ((size_t)-1 != nConv &&  nOutSize != nBufferSize) {
+            switch (errno) {
+              case E2BIG:
+                errormessage = "There is not sufficient room in buffer";
+                break;
+              case EILSEQ:
+                errormessage = "An invalid multibyte sequence has been 
encountered in the input";
+                break;
+              case EINVAL:
+                errormessage = "An incomplete multibyte sequence has been 
encountered in the input";
+                break;
+              default:
+                errormessage = "Unknown";
+                break;
+            }
+            msSetError(MS_MISCERR, "Unable to convert string in encoding 
'%s' to UTF8: %s",
+                                   "msConvertWideStringToUTF8()",
+                       encoding,errormessage);
+            iconv_close(cd);
+            msFree(output);
+            return NULL;
+          }
             iconv_close(cd);
          } else {
              msSetError(MS_MISCERR, "Encoding not supported by libiconv 
(%s).",
                                     "msConvertWideStringToUTF8()",
                                     encoding);
+           msFree(output);
              return NULL;
          }
-
-        if (bconvFailed) {
-            msFree(output);
-            output = NULL;
-            msSetError(MS_MISCERR, "Unable to convert string in encoding 
'%s' to UTF8",
-                                   "msConvertWideStringToUTF8()",
-                                   encoding);
-        }
      } else {
          /* we were given a NULL wide string, nothing we can do here */
          return NULL;

-- 
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