Hi,
On 30/06/2025 13:37, Ron Yorston wrote:
@@ -219,6 +219,10 @@ shell_builtin_read(struct builtin_read_params *params)
if (poll(pfd, 1, timeout) <= 0) {
/* timed out, or EINTR */
The comment here is wrong, this can (rarely) fail for other reasons than
timeout or EINTR, so...
err = errno;
+ if (err != EINTR) {
...this should check if (!err) to ensure that truly only timeouts result
in a return value of 2.
An incredibly contrived test case with your patch applied:
$ time ./busybox sh -c 'ulimit -n 0; read -t 10'; echo $?
real 0m0.007s
user 0m0.000s
sys 0m0.000s
142
That is, this exited immediately because poll() failed with EINVAL, but
the return value indicates that this timed out.
With the change I am suggesting here, this exits with status 1 instead.
Alternatively, poll()'s result could be used instead rather than errno
to distinguish between error and timeout.
Other than that, it looks like a good change to me!
Cheers,
Harald van Dijk
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