On 3/4/20 9:24 AM, Dan Gohman wrote:
Would if (flags & ((O_CREAT | O_WRONLY | O_RDWR) & ~O_RDONLY)) be correct?That would fix the problem for systems that define O_RDONLY as Hurd does, while not breaking any known systems. It wouldn't be correct on a hypothetical system
Thanks for mentioning this. We might as well fix the code for the hypothetical systems while we're at it, since we can use O_ACCMODE here. The issue also occurs in the 'open' wrapper. I installed the attached patch.
>From 1d86584739a712597a6fe3a62ec412238f0f13f8 Mon Sep 17 00:00:00 2001 From: Paul Eggert <[email protected]> Date: Sat, 7 Mar 2020 11:02:05 -0800 Subject: [PATCH] open, openat: port to (O_RDWR | O_RDONLY) != 0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Potential portability problem reported by Dan Gohman in: https://lists.gnu.org/r/bug-gnulib/2020-03/msg00000.html * lib/open.c (open): * lib/openat.c (rpl_openat): Don’t assume O_RDONLY is disjoint from O_RDWR. --- ChangeLog | 9 +++++++++ lib/open.c | 4 +++- lib/openat.c | 4 +++- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index 0eddfee99..f6bd5180c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2020-03-07 Paul Eggert <[email protected]> + + open, openat: port to (O_RDWR | O_RDONLY) != 0 + Potential portability problem reported by Dan Gohman in: + https://lists.gnu.org/r/bug-gnulib/2020-03/msg00000.html + * lib/open.c (open): + * lib/openat.c (rpl_openat): + Don’t assume O_RDONLY is disjoint from O_RDWR. + 2020-03-07 Bruno Haible <[email protected]> findprog, relocatable-prog: Ignore directories during PATH search. diff --git a/lib/open.c b/lib/open.c index 487194f66..bb180fde2 100644 --- a/lib/open.c +++ b/lib/open.c @@ -110,7 +110,9 @@ open (const char *filename, int flags, ...) directories, - if O_WRONLY or O_RDWR is specified, open() must fail because the file does not contain a '.' directory. */ - if (flags & (O_CREAT | O_WRONLY | O_RDWR)) + if ((flags & O_CREAT) + || (flags & O_ACCMODE) == O_RDWR + || (flags & O_ACCMODE) == O_WRONLY) { size_t len = strlen (filename); if (len > 0 && filename[len - 1] == '/') diff --git a/lib/openat.c b/lib/openat.c index 7d67dc4ca..fdbe83f43 100644 --- a/lib/openat.c +++ b/lib/openat.c @@ -100,7 +100,9 @@ rpl_openat (int dfd, char const *filename, int flags, ...) directories, - if O_WRONLY or O_RDWR is specified, open() must fail because the file does not contain a '.' directory. */ - if (flags & (O_CREAT | O_WRONLY | (O_RDWR & ~O_RDONLY))) + if ((flags & O_CREAT) + || (flags & O_ACCMODE) == O_RDWR + || (flags & O_ACCMODE) == O_WRONLY) { size_t len = strlen (filename); if (len > 0 && filename[len - 1] == '/') -- 2.17.1
