This allows an optimization that consists in the "perfetto" cmdline
client passing directly the file descriptor for the output trace
to traced (as opposite to having traced streaming back the trace
data to "perfetto" and having that one doing the write() into file).
This reduces sensibly the memory traffic and CPU overhead of traces
with a minor change.
Bug: 73625179
Test: builds + perfetto_integrationtests w/ long_trace.cfg
Change-Id: I81f5a230338ced20dc543fd91c5a0bd0e58725f2
The previous selinux rules obtained via audit2allow didn't really
work with the case of apps connecting to the producer socket,
despite all the allow rules being correctly in place.
This was failing our CTS tests.
The reason for the failure (see denials pasted below) is due to
Multi Level Security (for multi-user), which was still preventing
apps form a different level to connect to the traced producer
socket and write to the shmem buffers they get passed back.
This CL tags the objects being accessed as mlstrusted.
CTS tests pass with this CL.
Denials:
avc: denied { write } for pid=8545 comm="traced_probes" name="traced_producer" dev="tmpfs" ino=23629 scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:object_r:traced_producer_socket:s0 tclass=sock_file permissive=1
avc: denied { write } for pid=8545 comm="traced_probes" name="traced_producer" dev="tmpfs" ino=23629 scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:object_r:traced_producer_socket:s0 tclass=sock_file permissive=1
avc: denied { connectto } for pid=8545 comm="traced_probes" path="/dev/socket/traced_producer" scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:r:traced:s0 tclass=unix_stream_socket permissive=1
avc: denied { connectto } for pid=8545 comm="traced_probes" path="/dev/socket/traced_producer" scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:r:traced:s0 tclass=unix_stream_socket permissive=1
avc: denied { write } for pid=8545 comm="traced_probes" path=2F6D656D66643A706572666574746F5F73686D656D202864656C6574656429 dev="tmpfs" ino=104483 scontext=u:r:untrusted_app_25:s0:c512,c768 tcontext=u:object_r:traced_tmpfs:s0 tclass=file permissive=1
Change-Id: I1598bc0b07bf39b8d0420b66caf06a4ca884f383
Bug: 73340039
Test: CtsPerfettoTestCases
Restrictions introduced in vendor init mean that new devices
may not no longer exempt vendor init from writing to system_data_file.
This means we must introduce a new label for /data/vendor which
vendor_init may write to.
Bug: 73087047
Test: build and boot Taimen and Marlin. Complete SUW, enroll fingerprint
No new denials.
Change-Id: I65f904bb28952d4776aab947515947e14befbe34
Perfetto is a performance instrumentation and logging framework,
living in AOSP's /external/pefetto.
Perfetto introduces in the system one binary and two daemons
(the binary can specialize in either depending on the cmdline).
1) traced: unprivileged daemon. This is architecturally similar to logd.
It exposes two UNIX sockets:
- /dev/socket/traced_producer : world-accessible, allows to stream
tracing data. A tmpfs file descriptor is sent via SCM_RIGHTS
from traced to each client process, which needs to be able to
mmap it R/W (but not X)
- /dev/socket/traced_consumer : privilege-accessible (only from:
shell, statsd). It allows to configure tracing and read the trace
buffer.
2) traced_probes: privileged daemon. This needs to:
- access tracingfs (/d/tracing) to turn tracing on and off.
- exec atrace
- connect to traced_producer to stream data to traced.
init.rc file:
https://android-review.googlesource.com/c/platform/external/perfetto/+/575382/14/perfetto.rc
Bug: 70942310
Change-Id: Ia3b5fdacbd5a8e6e23b82f1d6fabfa07e4abc405
