64bit segfault in cygcheck

[Peter Rosin]

Hi!

I did a "cygcheck -svc", mostly for fun, and got a segfault. A gbd
session puts the blame on cygcheck.cc:671, which currently has this:

670:	  struct tm *tm = localtime ((const time_t *) &(ed->timestamp));
671:	  if (tm->tm_year < 60)
672:	    tm->tm_year += 2000;

The reproducer I have is:

$ cygcheck -v /bin/cygruby191.dll
Segmentation fault
$

So, since I'm not set up to build my own cygwin dll (not
comfortably anyway), I will try a blind patch and leave the
testing of it to someone else.

I haven't researched what's up with that dll, and why localtime()
would fail, but checking the return value is the right thing to do
regardless if there are other issues.

Cheers,
Peter

Index: cygcheck.cc
===================================================================
RCS file: /cvs/src/src/winsup/utils/cygcheck.cc,v
retrieving revision 1.137
diff -u -r1.137 cygcheck.cc
--- cygcheck.cc	21 Jan 2013 16:28:27 -0000	1.137
+++ cygcheck.cc	28 Mar 2013 15:08:29 -0000
@@ -668,16 +668,19 @@
 	  ExpDirectory *ed = (ExpDirectory *) exp;
 	  int ofs = ed->name_rva - export_rva;
 	  struct tm *tm = localtime ((const time_t *) &(ed->timestamp));
-	  if (tm->tm_year < 60)
+	  if (tm && tm->tm_year < 60)
 	    tm->tm_year += 2000;
-	  if (tm->tm_year < 200)
+	  if (tm && tm->tm_year < 200)
 	    tm->tm_year += 1900;
 	  printf ("%*c", lvl + 2, ' ');
-	  printf ("\"%s\" v%d.%d ts=", exp + ofs,
+	  printf ("\"%s\" v%d.%d", exp + ofs,
 		  ed->major_ver, ed->minor_ver);
-	  printf ("%d/%d/%d %d:%02d\n",
-		  tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
-		  tm->tm_hour, tm->tm_min);
+	  if (tm)
+	    printf (" ts=%d/%d/%d %d:%02d\n",
+		    tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
+		    tm->tm_hour, tm->tm_min);
+	  else
+	    printf ("\n");
 	}
     }