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authorLuke Shumaker <LukeShu@sbcglobal.net>2012-11-25 20:05:09 -0500
committerLuke Shumaker <LukeShu@sbcglobal.net>2012-11-25 20:28:14 -0500
commite9836b6b2afa70f22d305509593b375543b20ba6 (patch)
tree9695c79202bb58c4014033f98a0021790f49817e
parent2343d5c3c034c2597a034f5a5de9373d7e076e60 (diff)
downloaddevtools-e9836b6b2afa70f22d305509593b375543b20ba6.tar.xz
Use common functions to handle file locking
* lib/common.sh: implement - lock_open_write() - lock_open_read() - lock_close() * archbuild.in, makechrootpkg.in, mkarchroot.in: use said functions This has two benefits: 1. All programs using these methods gain the ability to inherit locks, something that only mkarchroot could do before. This allows the commands to be more compos-able. 2. It is more readable. File locking isn't obvious.
-rw-r--r--archbuild.in9
-rw-r--r--lib/common.sh49
-rw-r--r--makechrootpkg.in17
-rw-r--r--mkarchroot.in12
4 files changed, 55 insertions, 32 deletions
diff --git a/archbuild.in b/archbuild.in
index 7220391..9476415 100644
--- a/archbuild.in
+++ b/archbuild.in
@@ -43,17 +43,12 @@ if ${clean_first} || [[ ! -d "${chroots}/${repo}-${arch}" ]]; then
[[ -d $copy ]] || continue
msg2 "Deleting chroot copy '$(basename "${copy}")'..."
- exec 9>"$copy.lock"
- if ! flock -n 9; then
- stat_busy "Locking chroot copy '$copy'"
- flock 9
- stat_done
- fi
+ lock_open_write 9 "$copy.lock" "Locking chroot copy '$copy'"
{ type -P btrfs && btrfs subvolume delete "${copy}"; } &>/dev/null
rm -rf --one-file-system "${copy}"
done
- exec 9>&-
+ lock_close 9
rm -rf --one-file-system "${chroots}/${repo}-${arch}"
mkdir -p "${chroots}/${repo}-${arch}"
diff --git a/lib/common.sh b/lib/common.sh
index b39bbbc..5204091 100644
--- a/lib/common.sh
+++ b/lib/common.sh
@@ -104,6 +104,55 @@ in_array() {
}
##
+# usage : lock_open_write( $fd, $path, $wait_message )
+##
+lock_open_write() {
+ local fd=$1
+ local path=$2
+ local msg=$3
+
+ # Only reopen the FD if it wasn't handed to us
+ if [[ $(readlink -f /dev/fd/$fd) != "${path}.lock" ]]; then
+ eval "exec $fd>${path}.lock"
+ fi
+
+ if ! flock -n $fd; then
+ stat_busy "$msg"
+ flock $fd
+ stat_done
+ fi
+}
+
+##
+# usage : lock_open_read( $fd, $path, $wait_message )
+##
+lock_open_read() {
+ local fd=$1
+ local path=$2
+ local msg=$3
+
+ # Only reopen the FD if it wasn't handed to us
+ if [[ $(readlink -f /dev/fd/$fd) != "${path}.lock" ]]; then
+ eval "exec $fd>${path}.lock"
+ fi
+
+ if ! flock -sn $fd; then
+ stat_busy "$msg"
+ flock -s $fd
+ stat_done
+ fi
+}
+
+
+##
+# usage : lock_close( $fd )
+##
+lock_close() {
+ local fd=$1
+ eval "exec $fd>&-"
+}
+
+##
# usage : get_full_version( [$pkgname] )
# return : full version spec, including epoch (if necessary), pkgver, pkgrel
##
diff --git a/makechrootpkg.in b/makechrootpkg.in
index 6c0b013..f3333ca 100644
--- a/makechrootpkg.in
+++ b/makechrootpkg.in
@@ -114,23 +114,12 @@ umask 0022
# Lock the chroot we want to use. We'll keep this lock until we exit.
# Note this is the same FD number as in mkarchroot
-exec 9>"$copydir.lock"
-if ! flock -n 9; then
- stat_busy "Locking chroot copy '$copy'"
- flock 9
- stat_done
-fi
+lock_open_write 9 "$copydir.lock" "Locking chroot copy '$copy'"
if [[ ! -d $copydir ]] || $clean_first; then
# Get a read lock on the root chroot to make
# sure we don't clone a half-updated chroot
- exec 8>"$chrootdir/root.lock"
-
- if ! flock -sn 8; then
- stat_busy "Locking clean chroot"
- flock -s 8
- stat_done
- fi
+ lock_open_read 8 "$chrootdir/root.lock" "Locking clean chroot"
stat_busy 'Creating clean working copy'
use_rsync=false
@@ -149,7 +138,7 @@ if [[ ! -d $copydir ]] || $clean_first; then
stat_done
# Drop the read lock again
- exec 8>&-
+ lock_close 8
fi
if [[ -n $install_pkg ]]; then
diff --git a/mkarchroot.in b/mkarchroot.in
index 76ad840..022943e 100644
--- a/mkarchroot.in
+++ b/mkarchroot.in
@@ -183,17 +183,7 @@ trap_chroot_umount () {
}
chroot_lock () {
- # Only reopen the FD if it wasn't handed to us
- if [[ $(readlink -f /dev/fd/9) != "${working_dir}.lock" ]]; then
- exec 9>"${working_dir}.lock"
- fi
-
- # Lock the chroot. Take note of the FD number.
- if ! flock -n 9; then
- stat_busy "Locking chroot"
- flock 9
- stat_done
- fi
+ lock_open_write 9 "${working_dir}.lock" "Locking chroot"u
}
chroot_run() {