Disallow operator!() on unique_fd
This catches a common mistake where client code checks for errors using
the common idiom that works for std::iostream and other file-like
classes:
unique_fd fd = open(...);
if (!fd) {
}
Test: atest libbase_test
Test: m droid
Change-Id: I9629a7795537ecb3b57be9c741c06f80967e4cc2
diff --git a/base/include/android-base/unique_fd.h b/base/include/android-base/unique_fd.h
index 83213e9..3fa3bea 100644
--- a/base/include/android-base/unique_fd.h
+++ b/base/include/android-base/unique_fd.h
@@ -105,6 +105,9 @@
int get() const { return fd_; }
operator int() const { return get(); } // NOLINT
+ // Catch bogus error checks (i.e.: "!fd" instead of "fd != -1").
+ bool operator!() const = delete;
+
int release() __attribute__((warn_unused_result)) {
tag(fd_, this, nullptr);
int ret = fd_;
diff --git a/init/service.cpp b/init/service.cpp
index 6d08cb1..f5c13b9 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -177,7 +177,7 @@
Result<Success> Service::EnterNamespaces() const {
for (const auto& [nstype, path] : namespaces_to_enter_) {
auto fd = unique_fd{open(path.c_str(), O_RDONLY | O_CLOEXEC)};
- if (!fd) {
+ if (fd == -1) {
return ErrnoError() << "Could not open namespace at " << path;
}
if (setns(fd, nstype) == -1) {