From ba0067d5376f258d15765d876a96b9ef56bc40bb Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Tue, 15 Apr 2025 18:44:55 -0700 Subject: [PATCH] close-stream: don't clobber errno upon prior failure MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Don't reset errno when returning due to a prior stream error. * lib/close-stream.c (close_stream): Don't clobber errno if prev_fail is true. Reported by Jaroslav Škarvada in https://bugs.gnu.org/77800 --- ChangeLog | 7 +++++++ lib/close-stream.c | 19 +++++++++++-------- 2 files changed, 18 insertions(+), 8 deletions(-) diff --git a/ChangeLog b/ChangeLog index 28322a2655..7c09f61044 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2025-04-15 Jim Meyering + + close-stream: don't clobber errno upon prior failure + Don't reset errno when returning due to a prior stream error. + * lib/close-stream.c (close_stream): Don't clobber errno if prev_fail + is true. Reported by Jaroslav Škarvada in https://bugs.gnu.org/77800 + 2025-04-15 Paul Eggert dfa: pacify gcc -Wstringop-overflow diff --git a/lib/close-stream.c b/lib/close-stream.c index 5dbb19c6ce..bf22f9f454 100644 --- a/lib/close-stream.c +++ b/lib/close-stream.c @@ -61,17 +61,20 @@ close_stream (FILE *stream) /* Return an error indication if there was a previous failure or if fclose failed, with one exception: ignore an fclose failure if there was no previous error, no data remains to be flushed, and - fclose failed with EBADF. That can happen when a program like cp - is invoked like this 'cp a b >&-' (i.e., with standard output - closed) and doesn't generate any output (hence no previous error - and nothing to be flushed). */ + fclose failed with EBADF. In the case of an ignorable fclose + failure, clear errno to avoid misleading diagnostics. That can + happen when a program like cp is invoked like this 'cp a b >&-' + (i.e., with standard output closed) and doesn't generate any output + (hence no previous error and nothing to be flushed). */ - if (prev_fail || (fclose_fail && (some_pending || errno != EBADF))) + if (!prev_fail && fclose_fail && !some_pending && errno == EBADF) { - if (! fclose_fail) - errno = 0; - return EOF; + errno = 0; + return 0; } + if (prev_fail || (fclose_fail && some_pending)) + return EOF; + return 0; } -- 2.49.0.281.g77d6ee513f