[perl #57776] [BUG] PIO_buf_read segfault

[Stephane Payrard via RT]

A better patch that stats the opened file.
That avoids possible race conditions and is faster.
thx to jonathan and NotFound for pointing the shortcomings of the previous 
patch.

# now the test pass
ok 3 - slurp() on directories fails


--- ./src/io/io_unix.c.orig     2008-09-19 17:56:19.000000000 +0200
+++ ./src/io/io_unix.c  2008-09-19 19:16:04.000000000 +0200



@@ -353,6 +353,14 @@
     }
 
     if (fd >= 0) {
+        struct stat buf;
+        if (fstat(fd, &buf) == -1) 
+            return NULL;
+        if ((buf.st_mode & S_IFMT) == S_IFDIR) {
+            errno = EISDIR;
+            return NULL;
+        }
+        
         /* Set generic flag here if is a terminal then
          * higher layers can know how to setup buffering.
          * STDIN, STDOUT, STDERR would be in this case