From a1de7e8e08246a6842e62da82383eb8920689ee4 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 20 May 2020 18:20:47 -0700
Subject: [PATCH] ircd::fs::fd: Replace open(2) with openat(2); additional
 constructor.

---
 include/ircd/fs/fd.h |  1 +
 ircd/fs.cc           | 29 ++++++++++++++++++++++++-----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/include/ircd/fs/fd.h b/include/ircd/fs/fd.h
index 282f86a93..80b81b207 100644
--- a/include/ircd/fs/fd.h
+++ b/include/ircd/fs/fd.h
@@ -42,6 +42,7 @@ struct ircd::fs::fd
 	int release() noexcept;
 
 	explicit fd(const int &);
+	fd(const int &dirfd, const string_view &path, const opts &);
 	fd(const string_view &path, const opts &);
 	fd(const string_view &path);
 	fd() = default;
diff --git a/ircd/fs.cc b/ircd/fs.cc
index 1a33fe259..30155afdf 100644
--- a/ircd/fs.cc
+++ b/ircd/fs.cc
@@ -1994,19 +1994,38 @@ ircd::fs::fd::opts::opts(const std::ios::openmode &mode)
 //
 
 ircd::fs::fd::fd(const int &fdno)
-:fdno{fdno}
+:fdno
+{
+	fdno
+}
 {
 }
 
 ircd::fs::fd::fd(const string_view &path)
-:fd{path, opts{}}
+:fd
+{
+	path, opts{}
+}
 {
 }
 
 ircd::fs::fd::fd(const string_view &path,
                  const opts &opts)
+:fd
+{
+	AT_FDCWD, path, opts
+}
+{
+}
+
+ircd::fs::fd::fd(const int &dirfd,
+                 const string_view &path,
+                 const opts &opts)
 try
-:fdno{-1}
+:fdno
+{
+	-1 // sentinel value for inert dtor
+}
 {
 	const mode_t mode
 	{
@@ -2033,11 +2052,11 @@ try
 
 	const prof::syscall_usage_warning message
 	{
-		"fs::fs::fd(): open(2): %s", path
+		"fs::fs::fd(): openat(2): %s", path
 	};
 
 	assert((flags & ~O_CREAT) || mode != 0);
-	fdno = syscall(::open, path_cstr(path), flags, mode);
+	fdno = syscall(::openat, dirfd, path_cstr(path), flags, mode);
 
 	if(advise)
 		fs::advise(*this, advise);