[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents
From: |
Eli Zaretskii |
Subject: |
bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported |
Date: |
Tue, 08 Aug 2023 22:27:23 +0300 |
> Cc: 65156@debbugs.gnu.org
> Date: Tue, 08 Aug 2023 21:33:55 +0300
> From: Eli Zaretskii <eliz@gnu.org>
>
> > Date: Tue, 8 Aug 2023 20:20:23 +0200
> > From: Lucas Werkmeister <mail@lucaswerkmeister.de>
> >
> > Launch graphical Emacs with standard input attached to a pipe, then
> > attempt to insert /dev/stdin, for example:
> >
> > echo test | emacs -Q --insert /dev/stdin
> > echo test | emacs -Q --eval '(insert-file-contents "/dev/stdin")'
> >
> > This now results in an error (and nothing inserted into the buffer):
> > "Maximum buffer size exceeded".
>
> The doc string says:
>
> When inserting data from a special file (e.g., /dev/urandom), you
> can’t specify VISIT or BEG, and END should be specified to avoid
> inserting unlimited data into the buffer.
>
> > Previously, this used to work; git bisect identifies cb4579ed6b ("Allow
> > inserting parts of /dev/urandom with insert-file-contents", bug#18370)
> > as the first bad commit.
> >
> > Other (non-stdin) pipes are also affected. Testing with a named pipe
> > shows that the error only occurs after the pipe is first written to:
> >
> > # first terminal:
> > mkfifo /tmp/fifo
> > emacs -Q
> > M-x insert-file /tmp/fifo
> > # second terminal:
> > { echo x; sleep 10; echo y; } > /tmp/fifo
> >
> > Before you run the command in the second terminal, you can observe that
> > Emacs is just waiting for input from the pipe; as soon as you run the
> > other command, Emacs shows the error before the sleep finishes.
>
> Lars, Paul, any suggestions?
I installed the patch below on the emacs-29 branch; please see if it
solves your problems with reading from pipes.
Paul, can there be a regular file that is not seekable? If regular
files are always seekable, the patch can be simplified.
diff --git a/src/fileio.c b/src/fileio.c
index 995e414..55132f1 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4581,7 +4581,7 @@ because (1) it preserves some marker positions (in
unchanged portions
goto handled;
}
- if (seekable || !NILP (end))
+ if ((seekable && regular) || !NILP (end))
total = end_offset - beg_offset;
else
/* For a special file, all we can do is guess. */
@@ -4678,7 +4678,7 @@ because (1) it preserves some marker positions (in
unchanged portions
For a special file, where TOTAL is just a buffer size,
so don't bother counting in HOW_MUCH.
(INSERTED is where we count the number of characters inserted.) */
- if (seekable || !NILP (end))
+ if ((seekable && regular) || !NILP (end))
how_much += this;
inserted += this;
}
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Lucas Werkmeister, 2023/08/08
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Eli Zaretskii, 2023/08/08
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported,
Eli Zaretskii <=
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Paul Eggert, 2023/08/09
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Eli Zaretskii, 2023/08/10
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Paul Eggert, 2023/08/10
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Eli Zaretskii, 2023/08/10
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Paul Eggert, 2023/08/11
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Eli Zaretskii, 2023/08/11
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Paul Eggert, 2023/08/11
- bug#65156: 29.1; Reading from pipe with --insert or insert-file-contents no longer supported, Eli Zaretskii, 2023/08/12