Code around the stat-on-a-pipe-returns-a-mode-of-zero bug

reported several times by Dominic Dunlop, for example in
ID 20000315.008.  Patch from Dominic.  Patch affects at
least MachTen, and possibly other oldish BSDs. Should not
break non-broken platforms (tested on LinuxPPC).

p4raw-id: //depot/perl@7148

diff --git a/doio.c b/doio.c
index ceb8321..de613f4 100644 (file)
--- a/doio.c
+++ b/doio.c
@@ -320,7 +320,16 @@ Perl_do_open9(pTHX_ GV *gv, register char *name, I32 len, int as_raw,
                             * fsetpos(src)+fgetpos(dst)?  --nik */
                            PerlIO_flush(fp);
                            fd = PerlIO_fileno(fp);
-                           if (IoTYPE(thatio) == IoTYPE_SOCKET)
+                           /* When dup()ing STDIN, STDOUT or STDERR
+                            * explicitly set appropriate access mode */
+                           if (IoIFP(thatio) == PerlIO_stdout()
+                               || IoIFP(thatio) == PerlIO_stderr())
+                               IoTYPE(io) = IoTYPE_WRONLY;
+                           else if (IoIFP(thatio) == PerlIO_stdin())
+                                IoTYPE(io) = IoTYPE_RDONLY;
+                           /* When dup()ing a socket, say result is
+                            * one as well */
+                           else if (IoTYPE(thatio) == IoTYPE_SOCKET)
                                IoTYPE(io) = IoTYPE_SOCKET;
                        }
                        else
@@ -450,7 +459,9 @@ Perl_do_open9(pTHX_ GV *gv, register char *name, I32 len, int as_raw,
 #else
            !PL_statbuf.st_mode
 #endif
-       ) {
+           && IoTYPE(io) != IoTYPE_WRONLY  /* Dups of STD* filehandles already have */
+           && IoTYPE(io) != IoTYPE_RDONLY  /* type so they aren't marked as sockets */
+       ) {                                 /* on OS's that return 0 on fstat()ed pipe */
            char tmpbuf[256];
            Sock_size_t buflen = sizeof tmpbuf;
            if (PerlSock_getsockname(PerlIO_fileno(fp), (struct sockaddr *)tmpbuf,