RFR: 8289643: File descriptor leak with ProcessBuilder.startPipeline [v7]
Roger Riggs
rriggs at openjdk.org
Mon Jul 18 17:53:16 UTC 2022
> The `ProcessBuilder.pipelineStart()` implementation does not close all of the file descriptors it uses to create the pipeline of processes.
>
> The process calling `pipelineStart()` is creating the pipes between the stages.
> As each process is launched, the file descriptor is inherited by the child process and
> the child process `dup`s them to the respective stdin/stdout/stderr fd.
> These copies of inherited file descriptors are handled correctly.
>
> Between the launching of each Process, the file descriptor for the read-side of the pipe for the output of the previous process is kept open (in the parent process invoking `pipelineStart`). The file descriptor is correctly passed to the child and is dup'd to the stdin of the next process.
>
> However, the open file descriptor in the parent is not closed after it has been used as the input for the next Process.
> The fix is to close the fd after it has been used as the input of the next process.
>
> A new test verifies that after `pipelineStart` is complete, the same file descriptors are open for Unix Pipes as before the test.
> The test only runs on Linux using the /proc/<pid>/fd filesystem to identify open file descriptors.
>
> The bug fix is in `ProcessBuilder.pipelineStart` and is applicable to all platforms.
Roger Riggs has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:
- Remove diagnostics output from ProcessBuilder
- Merge branch '8289643-pipeline-start-leak' of https://github.com/RogerRiggs/jdk into 8289643-pipeline-start-leak
- Add DEBUG diagnostics to determine cause of GitHub Action test failures due to unexpected pipes
- Merge branch 'master' into 8289643-pipeline-start-leak
- Add DEBUG diagnostics to determine cause of GitHub Action test failures due to unexpected pipes
- Use DirectoryStream and handle IOExceptions
- remove debug output
- Add TWR for Files.walk of /proc
- Cleanup of PipelineLeaksFD test improving error messages and source cleanup.
- 8289643: File descriptor leak with ProcessBuilder.startPipeline
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/9414/files
- new: https://git.openjdk.org/jdk/pull/9414/files/ffddeed9..095e76b2
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=9414&range=06
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=9414&range=05-06
Stats: 81632 lines in 1825 files changed: 42313 ins; 25394 del; 13925 mod
Patch: https://git.openjdk.org/jdk/pull/9414.diff
Fetch: git fetch https://git.openjdk.org/jdk pull/9414/head:pull/9414
PR: https://git.openjdk.org/jdk/pull/9414
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