From d4c97ea2f64cafd3e14e2817d2b805f0b0d541f1 Mon Sep 17 00:00:00 2001 From: Lukas Fleischer Date: Thu, 13 Oct 2011 17:23:19 +0200 Subject: 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 Signed-off-by: Dan McGee --- scripts/repo-add.sh.in | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/repo-add.sh.in b/scripts/repo-add.sh.in index 29b150c8..d147b875 100644 --- a/scripts/repo-add.sh.in +++ b/scripts/repo-add.sh.in @@ -520,13 +520,19 @@ remove() { } trap_exit() { + # unhook all traps to avoid race conditions + trap '' EXIT TERM HUP QUIT INT ERR + echo error "$@" - exit 1 + clean_up 1 } clean_up() { - local exit_code=$? + local exit_code=${1:-$?} + + # unhook all traps to avoid race conditions + trap '' EXIT TERM HUP QUIT INT ERR [[ -d $tmpdir ]] && rm -rf "$tmpdir" (( CLEAN_LOCK )) && [[ -f $LOCKFILE ]] && rm -f "$LOCKFILE" -- cgit v1.2.3-70-g09d2 From 241946cceaf4c90624794a17c6a13661ea9862a9 Mon Sep 17 00:00:00 2001 From: Lukas Fleischer Date: Thu, 13 Oct 2011 17:23:20 +0200 Subject: scripts/*.sh.in: Fix signal handler error messages 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 Signed-off-by: Dan McGee --- scripts/makepkg.sh.in | 4 +++- scripts/repo-add.sh.in | 6 ++++-- 2 files changed, 7 insertions(+), 3 deletions(-) (limited to 'scripts') diff --git a/scripts/makepkg.sh.in b/scripts/makepkg.sh.in index 50cf2725..09c1e963 100644 --- a/scripts/makepkg.sh.in +++ b/scripts/makepkg.sh.in @@ -179,7 +179,9 @@ clean_up() { ## set -E trap 'clean_up' 0 -trap 'trap_exit "$(gettext "TERM signal caught. Exiting...")"' TERM HUP QUIT +for signal in TERM HUP QUIT; do + trap "trap_exit \"$(gettext "%s signal caught. Exiting...")\" \"$signal\"" "$signal" +done trap 'trap_exit "$(gettext "Aborted by user! Exiting...")"' INT trap 'trap_exit "$(gettext "An unknown error has occurred. Exiting...")"' ERR diff --git a/scripts/repo-add.sh.in b/scripts/repo-add.sh.in index d147b875..5e1d7702 100644 --- a/scripts/repo-add.sh.in +++ b/scripts/repo-add.sh.in @@ -572,9 +572,11 @@ tmpdir=$(mktemp -d /tmp/repo-tools.XXXXXXXXXX) || (\ mkdir $tmpdir/tree trap 'clean_up' EXIT -trap 'trap_exit "$(gettext "TERM signal caught. Exiting...")"' TERM HUP QUIT +for signal in TERM HUP QUIT; do + trap "trap_exit \"$(gettext "%s signal caught. Exiting...")\" \"$signal\"" "$signal" +done trap 'trap_exit "$(gettext "Aborted by user! Exiting...")"' INT -trap 'trap_exit "$(gettext "An unknown error has occured. Exiting...")"' ERR +trap 'trap_exit "$(gettext "An unknown error has occurred. Exiting...")"' ERR declare -a args success=0 -- cgit v1.2.3-70-g09d2