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Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX
From: |
Jim Meyering |
Subject: |
Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX |
Date: |
Sun, 30 Dec 2018 13:32:33 -0800 |
On Sun, Dec 30, 2018 at 10:26 AM Bruno Haible <address@hidden> wrote:
...
> The test scenario I used on Linux and HP-UX is:
> - Preparation:
> $ cd tests
> $ echo a > a
> - Command:
> $ ../src/diff -N - a <&-
>
> Result on HP-UX:
> $ ../src/diff -N - a <&-
> diff: -: Bad file number
>
> Result on Linux:
> $ ../src/diff -N - a <&-
> 0a1
> > a
...
>
> On HP-UX:
>
> $ tusc ../src/diff -N - a <&-
> execve("../src/diff", 0x87fffffffffffb08, 0x87fffffffffffb30) = 0 [64-bit]
> ...
> ioctl(0, TCGETA, 0x87fffffffffff3e0) ..................... ERR#25 ENOTTY
> fstat(0, 0x87fffffffffff420) ............................. = 0
...
>
> On Linux:
>
> $ strace ../src/diff -N - a <&-
> execve("../src/diff", ["../src/diff", "-N", "-", "a"], [/* 78 vars */]) = 0
> ...
> ioctl(0, TCGETS, 0x7ffd75318810) = -1 EBADF (Bad file descriptor)
> fstat(0, 0x7ffd75318940) = -1 EBADF (Bad file descriptor)
...
>
> The crucial difference is the open("a", O_RDONLY...) call, which is meant
Hi Bruno,
Thanks for all of that analysis.
The crucial difference seems earlier than that. HP-UX's fstat
erroneously returns 0 for the invalid (closed) stdin file descriptor,
while Linux's returns EBADF.
GNU diff explicitly handles the case of a closed file descriptor (note
the test for errno == EBADF in diff.c). That test cannot do its job
when fstat is not POSIX-conforming. NEWS from diffutils-3.3 says this:
--new-file (-N) and --unidirectional-new-file now allow comparisons to "-".
A standard input that's closed acts like a nonexistent file.
One way to work around that HP-UX flaw is to make gnulib's fstat
replacement return EBADF when the return value would otherwise be 0,
yet fcntl (fd, F_GETFD) returns -1.
- Re: [Diffutils-devel] [platform-testers] new snapshot available: diffutils-3.6.17-d5ba, (continued)
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on Mac OS X 10.4, Bruno Haible, 2018/12/28
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Bruno Haible, 2018/12/28
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Bruno Haible, 2018/12/28
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Jim Meyering, 2018/12/28
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Bruno Haible, 2018/12/29
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Jim Meyering, 2018/12/29
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Bruno Haible, 2018/12/29
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Jim Meyering, 2018/12/30
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Bruno Haible, 2018/12/30
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX,
Jim Meyering <=
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Jim Meyering, 2018/12/30
- Re: [Diffutils-devel] diffutils-3.6.17-d5ba on HP-UX, Bruno Haible, 2018/12/31
Re: [Diffutils-devel] [platform-testers] new snapshot available: diffutils-3.6.17-d5ba, Bruno Haible, 2018/12/28
Re: [Diffutils-devel] diffutils-3.6.17-d5ba on AIX 7, Bruno Haible, 2018/12/28