hooks/pre-auto-gc: look in sysfs to see if a battery is known.

Barring any kernel bugs, if this directory exists and there is
a symlink in there (which will point to the battery object),
that means there is a battery known to the kernel.

No symlink should mean no battery as far as the kernel is concerned.

Change-Id: Ib12819a5bbb816f0ae5ca080e5812a2db08441e9

1 files changed, 5 insertions, 0 deletions

diff --git a/hooks/pre-auto-gc b/hooks/pre-auto-gc
index 110e3194..360e5e1f 100755
--- a/hooks/pre-auto-gc
+++ b/hooks/pre-auto-gc
@@ -38,6 +38,11 @@ elif test -x /usr/bin/pmset && /usr/bin/pmset -g batt |
         grep -q "Currently drawing from 'AC Power'"
 then
         exit 0
+elif test -d /sys/bus/acpi/drivers/battery && test 0 = \
+  "$(find /sys/bus/acpi/drivers/battery/ -type l | wc -l)";
+then
+        # No battery exists.
+        exit 0
 fi
 
 echo "Auto packing deferred; not on AC"