BpfRingBuffer: allow subclassing, add epoll support
Currently there's no mechanism to subscribe to changes in a BpfRingbuf,
and the existing wait() method can only block on a single bpf
ringbuffer.
Hence, add methods to interface with epoll_ctl() system call.
Also in code review of previous patchsets it came to light
that the constructor is needlessly 'private', thus change it
to 'protected' so that it can be subclassed.
Bug: 350094404
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I4d9b841f5e984c42acab629a723e69920c00b356
diff --git a/staticlibs/native/bpf_headers/include/bpf/BpfRingbuf.h b/staticlibs/native/bpf_headers/include/bpf/BpfRingbuf.h
index cd51004..cf90d60 100644
--- a/staticlibs/native/bpf_headers/include/bpf/BpfRingbuf.h
+++ b/staticlibs/native/bpf_headers/include/bpf/BpfRingbuf.h
@@ -20,6 +20,7 @@
#include <android-base/unique_fd.h>
#include <linux/bpf.h>
#include <poll.h>
+#include <sys/epoll.h>
#include <sys/mman.h>
#include <utils/Log.h>
@@ -139,12 +140,24 @@
static base::Result<std::unique_ptr<BpfRingbuf<Value>>> Create(
const char* path);
+ int epoll_ctl_add(int epfd, struct epoll_event *event) {
+ return epoll_ctl(epfd, EPOLL_CTL_ADD, mRingFd.get(), event);
+ }
+
+ int epoll_ctl_mod(int epfd, struct epoll_event *event) {
+ return epoll_ctl(epfd, EPOLL_CTL_MOD, mRingFd.get(), event);
+ }
+
+ int epoll_ctl_del(int epfd) {
+ return epoll_ctl(epfd, EPOLL_CTL_DEL, mRingFd.get(), NULL);
+ }
+
// Consumes all messages from the ring buffer, passing them to the callback.
// Returns the number of messages consumed or a non-ok result on error. If the
// ring buffer has no pending messages an OK result with count 0 is returned.
base::Result<int> ConsumeAll(const MessageCallback& callback);
- private:
+ protected:
// Empty ctor for use by Create.
BpfRingbuf() : BpfRingbufBase(sizeof(Value)) {}
};