On Haiku calling dup3 with the same file descriptor as both arguments suceeds.
The same happened on NetBSD until a year ago, so it is a simple #if defined change. Also submitted a bug report for Haiku [1]. Collin [1] https://dev.haiku-os.org/ticket/19476
>From ed91d9b1c2f697a39116da46b553dfc89474f490 Mon Sep 17 00:00:00 2001 From: Collin Funk <collin.fu...@gmail.com> Date: Wed, 12 Mar 2025 18:55:26 -0700 Subject: [PATCH] dup3: Fix behavior for equal file descriptors on Haiku. * lib/dup3.c (dup3) [__HAIKU__]: Set errno to EINVAL and return -1 if both file descriptors are equal. * doc/posix-functions/dup3.texi: Document the Haiku bug. --- ChangeLog | 7 +++++++ doc/posix-functions/dup3.texi | 3 ++- lib/dup3.c | 6 ++++-- 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/ChangeLog b/ChangeLog index 0d363007b7..55bbf3f5e4 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2025-03-12 Collin Funk <collin.fu...@gmail.com> + + dup3: Fix behavior for equal file descriptors on Haiku. + * lib/dup3.c (dup3) [__HAIKU__]: Set errno to EINVAL and return -1 if + both file descriptors are equal. + * doc/posix-functions/dup3.texi: Document the Haiku bug. + 2025-03-12 Bruno Haible <br...@clisp.org> fcntl-h: Fix GNULIB_defined_O_NONBLOCK on Haiku (regr. 2025-02-16). diff --git a/doc/posix-functions/dup3.texi b/doc/posix-functions/dup3.texi index e7e4a507d0..3e9bd79fb0 100644 --- a/doc/posix-functions/dup3.texi +++ b/doc/posix-functions/dup3.texi @@ -22,7 +22,8 @@ @node dup3 @item This function mistakenly succeeds when given two equal file descriptors on some platforms: @c https://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=58266 -NetBSD 10.0. +@c https://dev.haiku-os.org/ticket/19476 +NetBSD 10.0, Haiku. @end itemize Portability problems not fixed by Gnulib: diff --git a/lib/dup3.c b/lib/dup3.c index 70c55990b0..2d5d51a769 100644 --- a/lib/dup3.c +++ b/lib/dup3.c @@ -46,8 +46,10 @@ dup3 (int oldfd, int newfd, int flags) { have_dup3_really = 1; /* On NetBSD dup3 is a no-op when oldfd == newfd, but we are - expected to fail with error EINVAL. */ -# ifdef __NetBSD__ + expected to fail with error EINVAL. + + Likewise on Haiku. */ +# if defined __NetBSD__ || defined __HAIKU__ if (newfd == oldfd) { errno = EINVAL; -- 2.48.1
