mirrors/git-annex
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages 1 Wiki Activity Actions

async exception safety for external special remote processes

Browse source 
Since an external process can be in the middle of some operation when an
async exception is received, it has to be shut down then. Using
cleanupProcess will close its IO handles and send it a SIGTERM.

If a special remote choses to catch SIGTERM, it's fine for it to do some
cleanup then, but until it finishes, git-annex will be blocked waiting
for it. If a special remote blocked SIGTERM, it would cause a hang.
Mentioned in docs.

Also, in passing, fixed a FD leak, it was not closing the error handle
when shutting down the external. In practice that didn't matter before because
it was only run when git-annex was itself shutting down, but now that it
can run on exception, it would have been a problem.
This commit is contained in:
Joey Hess 2020-06-09 12:13:06 -04:00
parent a294a27f9d
commit a49d300545
No known key found for this signature in database
GPG key ID: DB12DB0FF05F8F38
4 changed files with 37 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

7
doc/design/external_special_remote_protocol.mdwn
View file

@ -403,6 +403,13 @@ remote.
git-annex will not talk to it any further. If the program receives
an ERROR from git-annex, it can exit with its own ERROR.
## signals
The external special remote program should not block SIGINT, or SIGTERM.
Doing so may cause git-annex to hang waiting on it to exit.
Of course it's ok to catch those signals and do some necessary cleanup
before exiting.
## long running network connections
Since an external special remote is started only when git-annex needs to