printf: set errno for read-only stream

* libc/stdio/wsetup.c (__swsetup_r): Set errno on failure.
* libc/stdio/fvwrite.c (__sfvwrite_r): Simplify.
* libc/stdio/wbuf.c (__swbuf_r): Likewise.
* libc/stdio/local.h (cantwrite): Adjust comment.

newlib/ChangeLog

@@ -1,3 +1,10 @@
+2011-06-13  Eric Blake  <eblake@redhat.com>
+
+	* libc/stdio/wsetup.c (__swsetup_r): Set errno on failure.
+	* libc/stdio/fvwrite.c (__sfvwrite_r): Simplify.
+	* libc/stdio/wbuf.c (__swbuf_r): Likewise.
+	* libc/stdio/local.h (cantwrite): Adjust comment.
+
 2011-06-09  Yaakov Selkowitz  <yselkowitz@...>
 
 	* libc/include/string.h (strdupa): New macro function.

newlib/libc/stdio/fvwrite.c

@@ -61,11 +61,7 @@ _DEFUN(__sfvwrite_r, (ptr, fp, uio),
 
   /* make sure we can write */
   if (cantwrite (ptr, fp))
-    {
-      fp->_flags |= __SERR;
-      ptr->_errno = EBADF;
-      return EOF;
-    }
+    return EOF;
 
   iov = uio->uio_iov;
   len = 0;

newlib/libc/stdio/local.h

@@ -113,7 +113,8 @@ extern _READ_WRITE_RETURN_TYPE _EXFUN(__swrite64,(struct _reent *, void *,
     }						\
   while (0)
 
-/* Return true iff the given FILE cannot be written now.  */
+/* Return true and set errno and stream error flag iff the given FILE
+   cannot be written now.  */
 
 #define	cantwrite(ptr, fp)                                     \
   ((((fp)->_flags & __SWR) == 0 || (fp)->_bf._base == NULL) && \

newlib/libc/stdio/wbuf.c

@@ -54,11 +54,7 @@ _DEFUN(__swbuf_r, (ptr, c, fp),
 
   fp->_w = fp->_lbfsize;
   if (cantwrite (ptr, fp))
-    {
-      fp->_flags |= __SERR;
-      ptr->_errno = EBADF;
-      return EOF;
-    }
+    return EOF;
   c = (unsigned char) c;
 
   ORIENT (fp, -1);

newlib/libc/stdio/wsetup.c

@@ -20,12 +20,13 @@
 #include <_ansi.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <errno.h>
 #include "local.h"
 
 /*
  * Various output routines call wsetup to be sure it is safe to write,
  * because either _flags does not include __SWR, or _buf is NULL.
- * _wsetup returns 0 if OK to write, nonzero otherwise.
+ * _wsetup returns 0 if OK to write, nonzero and set errno otherwise.
  */
 
 int
@@ -44,7 +45,11 @@ _DEFUN(__swsetup_r, (ptr, fp),
   if ((fp->_flags & __SWR) == 0)
     {
       if ((fp->_flags & __SRW) == 0)
-	return EOF;
+        {
+	  ptr->_errno = EBADF;
+	  fp->_flags |= __SERR;
+	  return EOF;
+        }
       if (fp->_flags & __SRD)
 	{
 	  /* clobber any ungetc data */
@@ -79,5 +84,11 @@ _DEFUN(__swsetup_r, (ptr, fp),
   else
     fp->_w = fp->_flags & __SNBF ? 0 : fp->_bf._size;
 
-  return (!fp->_bf._base && (fp->_flags & __SMBF)) ? EOF : 0;
+  if (!fp->_bf._base && (fp->_flags & __SMBF))
+    {
+      /* __smakebuf_r set errno, but not flag */
+      fp->_flags |= __SERR;
+      return EOF;
+    }
+  return 0;
 }