dd: piping from stdout gives Broken pipe

[BAMF0]

(Forwarded from Launchpad Bug #2125943)
Piping dd's output to some commands gives IO error: Broken pipe.

Reproduce

Run dd with any input file (here /dev/random count=256) and pipe the output to another command (here cmp /tmp/a):

# GNU
$ gnudd if=/dev/random count=256 | cmp /tmp/a
/tmp/a - differ: byte 1, line 1

# uutils
$ dd dev/randow count=256 | cmp /tmp/a
/tmp/a - differ: byte 1, line 1
dd: IO error: Broken pipe

System

• OS release: Ubuntu 25.10
• uutils coreutils version: 0.5.0 (built from main commit: 1d6bd99)

[ChrisDryden]

From a cursory glance this is being caused by the fact that the file reader reads until a delimiter, and it should be using a buffer read similar to whats implemented in head. This can be solved by leveraging the TakeAllBuffer in head in this utility.

[ChrisDryden]

Turns out it's not related to that previous comment. Same root cause as this: #10260 just need to add the pipe signal handlers

[ChrisDryden]

This should be resolved by this: #10354