From d036e2082679120dfaf4d670106aa29b585da8f6 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Tue, 21 Aug 2018 18:15:37 +0200
Subject: [PATCH] system/FileDescriptor: add openat() wrapper

---
 src/system/FileDescriptor.cxx | 12 ++++++++++++
 src/system/FileDescriptor.hxx |  5 +++++
 2 files changed, 17 insertions(+)

diff --git a/src/system/FileDescriptor.cxx b/src/system/FileDescriptor.cxx
index a6e176166..f2516b872 100644
--- a/src/system/FileDescriptor.cxx
+++ b/src/system/FileDescriptor.cxx
@@ -76,6 +76,18 @@ FileDescriptor::IsSocket() const noexcept
 
 #endif
 
+#ifdef __linux
+
+bool
+FileDescriptor::Open(FileDescriptor dir, const char *pathname,
+		     int flags, mode_t mode) noexcept
+{
+	fd = ::openat(dir.Get(), pathname, flags | O_NOCTTY | O_CLOEXEC, mode);
+	return IsDefined();
+}
+
+#endif
+
 bool
 FileDescriptor::Open(const char *pathname, int flags, mode_t mode) noexcept
 {
diff --git a/src/system/FileDescriptor.hxx b/src/system/FileDescriptor.hxx
index 61b8a0aa4..e3176df60 100644
--- a/src/system/FileDescriptor.hxx
+++ b/src/system/FileDescriptor.hxx
@@ -116,6 +116,11 @@ public:
 		return FileDescriptor(-1);
 	}
 
+#ifdef __linux
+	bool Open(FileDescriptor dir, const char *pathname,
+		  int flags, mode_t mode=0666) noexcept;
+#endif
+
 	bool Open(const char *pathname, int flags, mode_t mode=0666) noexcept;
 
 #ifdef _WIN32