[pacman-dev] [PATCH 1/3] repo-add: Avoid race condition in signal handlers
There is a small chance that a user sends SIGINT (or any other signal
that is trapped) when we're already in clean_up() which used to lead to
trap_exit() being executed and the remaining code in clean_up() being
skipped due to the bash signal/trap handler blocking EXIT (since its
handler is already being executed, even if it's interrupted).
In practice, this behaviour caused unexpected results (primarily because
pressing ^C at the wrong time left a lock file behind):
$ ./repo-add extra.db.tar.gz foobar
==> Extracting database to a temporary location...
^C
==> ERROR: Aborted by user! Exiting...
$ ./repo-add extra.db.tar.gz foobar
==> Extracting database to a temporary location...
==> ERROR: File 'foobar' not found.
==> No packages modified, nothing to do.
^C
==> ERROR: Aborted by user! Exiting...
$ ./repo-add extra.db.tar.gz foobar
==> ERROR: Failed to acquire lockfile: extra.db.tar.gz.lck.
==> ERROR: Held by process 18522
Fix this and reduce the chance of race conditions in signal handlers by:
* Unhooking all traps in both clean_up() and trap_exit().
* Call clean_up() explicitly in trap_exit() to make sure we remove the
lock file and the temporary directory even if we send SIGINT when
clean_up() is already being executed but didn't reach the unhook code
yet.
Also, add an optional parameter to clean_up() to allow for setting an
explicit exit code when we call clean_up() from trap_exit().
Signed-off-by: Lukas Fleischer
This includes some fixes to the messages that are displayed when a
signal is caught in makepkg or repo-add:
* Instead of always showing "==> ERROR: TERM signal caught. Exiting...",
replace "TERM" by whatever signal is actually caught.
* Fix a typo in the SIGERR error message in repo-add ("occurred" instead
of "occured"). Francois already fixed this for makepkg in 1e51b81c.
Signed-off-by: Lukas Fleischer
Replace "/tmp" with "${TMPDIR:-/tmp}" to allow for overriding the
hardcoded path.
Since we only use "/tmp" in conjunction with mktemp(1), we could also
have used "--tmpdir", which is GNU-ish, however (and the BSD counterpart
"-t" has been deprecated in GNU mktemp).
Signed-off-by: Lukas Fleischer
participants (1)
-
Lukas Fleischer