Prevent reentrant invocations. Minor bugfix.

At startup a pid file is checked.  If it exists, another beam
process is assumed to be running and start up is aborted.  Otherwise
a new pid file is created.  The existing pid is removed before
exiting (by epilogue_hook).

* backup.in (prologue_hook): Prepend beam_lock.
* lib/beam/common.in (backup_pidfile): New global.
(beam_lock,beam_unlock): New functions.

* lib/beam/s3.sh (s3_getmpoint): Fix regexp to take
into account s3backer invocation without --vhost.

3 files changed, 26 insertions, 4 deletions

diff --git a/backup.in b/backup.in
index 615fa12..ca479b1 100644
--- a/backup.in
+++ b/backup.in
@@ -124,2 +124,3 @@ backup() {
 umask ${backup_umask:-077}
+prologue_hook="beam_lock $prologue_hook"
 
diff --git a/lib/beam/common.in b/lib/beam/common.in
index 1be075e..7e69640 100644
--- a/lib/beam/common.in
+++ b/lib/beam/common.in
@@ -32,2 +32,3 @@ backup_verbose=
 backup_logfile="/var/log/backup"
+backup_pidfile="/var/run/beam.pid"
 backup_tmp_dir=/tmp
@@ -49,2 +50,18 @@ abend() {
 
+beam_lock() {
+  if [ -r $backup_pidfile ]; then
+        pid=$(head -n 1 $backup_pidfile)
+        if [ -z "$pid" ]; then
+                abend "pidfile $backup_pidfile exists but is unreadable or empty"
+        fi
+        abend "another beam process (pid $backup_pid) is still running; exiting"
+  fi
+  echo $$ > $backup_pidfile || exit 1
+  epilogue_hook="$epilogue_hook beam_unlock"
+}  
+
+beam_unlock() {
+  rm -f $backup_pidfile
+}  
+
 tarcode() {
diff --git a/lib/beam/s3.sh b/lib/beam/s3.sh
index de71456..d2fcfe6 100644
--- a/lib/beam/s3.sh
+++ b/lib/beam/s3.sh
@@ -28,5 +28,12 @@ s3_getmpoint()
   case $1 in
+# Sample mount output, split into several lines:
+# a) With --vhost:
+# http://BUCKETNAME.s3.amazonaws.com/ on /mnt/s3backer type fuse.s3backer
+#  (rw,nosuid,nodev,allow_other,default_permissions)
+# b) Without --vhost:
+# http://s3.amazonaws.com/BUCKETNAME/ on /mnt/s3backer type fuse.s3backer 
+#  (rw,nosuid,nodev,allow_other,default_permissions)
   backer)
     mount -tfuse.s3backer | 
-           awk '/https?:\/\/'$backup_bucket_name'/ { print $3 }';;
+           awk '/https?:\/\/.*'$backup_bucket_name'/ { print $3 }';;
   s3)
@@ -52,5 +59,2 @@ s3_mount() {
 
-# Sample mount output, split into several lines:
-# http://finox-backup-fs.s3.amazonaws.com/ on /mnt/s3backer type fuse.s3backer
-#  (rw,nosuid,nodev,allow_other,default_permissions)
   set -- $(s3_getmpoint backer)