Make a read from a write-only fh to set errno

(found by Gisle)

p4raw-id: //depot/perl@20019

1 files changed, 4 insertions, 1 deletions

diff --git a/perlio.c b/perlio.c
index 78b2d18be5..b0649df087 100644
--- a/perlio.c
+++ b/perlio.c
@@ -2033,8 +2033,11 @@ PerlIOBase_read(pTHX_ PerlIO *f, void *vbuf, Size_t count)
 {
     STDCHAR *buf = (STDCHAR *) vbuf;
     if (f) {
-	if (!(PerlIOBase(f)->flags & PERLIO_F_CANREAD))
+        if (!(PerlIOBase(f)->flags & PERLIO_F_CANREAD)) {
+	    PerlIOBase(f)->flags |= PERLIO_F_ERROR;
+	    SETERRNO(EBADF, SS_IVCHAN);
 	    return 0;
+	}
 	while (count > 0) {
 	    SSize_t avail = PerlIO_get_cnt(f);
 	    SSize_t take = 0;