tail: unnecessary pipe2 syscall for empty files
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U - tail
- Dominant language
- Rust
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Description
Description:
When running tail -c +1 /dev/null, tail makes an unnecessary pipe2
syscall even though the file is empty and has no data to transfer.
The pipe creation is wasteful in this case.
Steps to reproduce:
strace -c -e pipe,pipe2 tail -c +1 /dev/null
Expected behavior: No pipe2 syscall for empty/exhausted files.
Actual behavior: 1 pipe2 call despite nothing to transfer.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running strace -c -e pipe,pipe2 tail -c +1 /dev/null and tracing the tail implementation that handles byte offsets and empty or exhausted files. Confirm the change against this reproduction and ensure the command completes without a pipe2 syscall when there is no data to transfer.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- cli
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 58/100