init: use std::function for epoll handling
Also allow unregistering of epoll handlers.
Bug: 64114943
Test: boot
Change-Id: I2abe6a56fd451839931d607dddb91669a7d02ff1
diff --git a/init/init.cpp b/init/init.cpp
index 0d5690b..42032ca 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -31,6 +31,10 @@
#include <sys/types.h>
#include <unistd.h>
+#include <map>
+#include <memory>
+#include <optional>
+
#include <android-base/chrono_utils.h>
#include <android-base/file.h>
#include <android-base/logging.h>
@@ -43,9 +47,6 @@
#include <private/android_filesystem_config.h>
#include <selinux/android.h>
-#include <memory>
-#include <optional>
-
#include "action_parser.h"
#include "import_parser.h"
#include "init_first_stage.h"
@@ -130,12 +131,31 @@
}
}
-void register_epoll_handler(int fd, void (*fn)()) {
+static std::map<int, std::function<void()>> epoll_handlers;
+
+void register_epoll_handler(int fd, std::function<void()> handler) {
+ auto[it, inserted] = epoll_handlers.emplace(fd, std::move(handler));
+ if (!inserted) {
+ LOG(ERROR) << "Cannot specify two epoll handlers for a given FD";
+ return;
+ }
epoll_event ev;
ev.events = EPOLLIN;
- ev.data.ptr = reinterpret_cast<void*>(fn);
+ // std::map's iterators do not get invalidated until erased, so we use the pointer to the
+ // std::function in the map directly for epoll_ctl.
+ ev.data.ptr = reinterpret_cast<void*>(&it->second);
if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev) == -1) {
- PLOG(ERROR) << "epoll_ctl failed";
+ PLOG(ERROR) << "epoll_ctl failed to add fd";
+ epoll_handlers.erase(fd);
+ }
+}
+
+void unregister_epoll_handler(int fd) {
+ if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, nullptr) == -1) {
+ PLOG(ERROR) << "epoll_ctl failed to remove fd";
+ }
+ if (epoll_handlers.erase(fd) != 1) {
+ LOG(ERROR) << "Attempting to remove epoll handler for FD without an existing handler";
}
}
@@ -809,7 +829,7 @@
if (nr == -1) {
PLOG(ERROR) << "epoll_wait failed";
} else if (nr == 1) {
- ((void (*)()) ev.data.ptr)();
+ std::invoke(*reinterpret_cast<std::function<void()>*>(ev.data.ptr));
}
}