commit 1279013dee790c84758e5fc5bed33b5c9df2af9b
author Jamie Gennis <jgennis@google.com> Wed Jun 06 18:12:48 2012 -0700
committer Jamie Gennis <jgennis@google.com> Fri Jun 08 14:26:29 2012 -0700
tree 4fa97250b1edb75d88d29d722214c2d6606ebc8a
parent 88f11846a621b148387aa09754bc939933793717

Enable tracing on user builds

This change adds init.rc steps to:
 * allow kernel tracing to be enabled via adb
 * allow a limited set of kernel trace events to be enabled via adb
 * allow the kernel trace to be read via adb
 * allow all users to write to the kernel trace from userland

Bug: 6513400
Change-Id: Ic3c189b5697aa5edf88d2f507c932971bed6caff

rootdir/init.trace.rc

diff --git a/rootdir/init.trace.rc b/rootdir/init.trace.rc
new file mode 100644
index 0000000..1d114f5
--- /dev/null
+++ b/rootdir/init.trace.rc
@@ -0,0 +1,31 @@
+## Permissions to allow system-wide tracing to the kernel trace buffer.
+##
+on boot
+
+# Allow writing to the kernel trace log.
+    chmod 0222 /sys/kernel/debug/tracing/trace_marker
+
+# Allow the shell group to enable (some) kernel tracing.
+    chown root shell /sys/kernel/debug/tracing/trace_clock
+    chown root shell /sys/kernel/debug/tracing/buffer_size_kb
+    chown root shell /sys/kernel/debug/tracing/options/overwrite
+    chown root shell /sys/kernel/debug/tracing/events/sched/sched_switch/enable
+    chown root shell /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
+    chown root shell /sys/kernel/debug/tracing/events/power/cpu_frequency/enable
+    chown root shell /sys/kernel/debug/tracing/events/power/cpu_idle/enable
+    chown root shell /sys/kernel/debug/tracing/events/cpufreq_interactive/enable
+    chown root shell /sys/kernel/debug/tracing/tracing_on
+
+    chmod 0664 /sys/kernel/debug/tracing/trace_clock
+    chmod 0664 /sys/kernel/debug/tracing/buffer_size_kb
+    chmod 0664 /sys/kernel/debug/tracing/options/overwrite
+    chmod 0664 /sys/kernel/debug/tracing/events/sched/sched_switch/enable
+    chmod 0664 /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
+    chmod 0664 /sys/kernel/debug/tracing/events/power/cpu_frequency/enable
+    chmod 0664 /sys/kernel/debug/tracing/events/power/cpu_idle/enable
+    chmod 0664 /sys/kernel/debug/tracing/events/cpufreq_interactive/enable
+    chmod 0664 /sys/kernel/debug/tracing/tracing_on
+
+# Allow only the shell group to read and truncate the kernel trace.
+    chown root shell /sys/kernel/debug/tracing/trace
+    chmod 0660 /sys/kernel/debug/tracing/trace