From bd9eb367a092f7034d22d4a2c860ce1e56df8e34 Mon Sep 17 00:00:00 2001
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
Date: Wed, 9 Jun 2021 15:18:45 +0200
Subject: [PATCH] Syscalls/Tools: add renameat2

Mostly for the ability to atomically swap files.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
 src/PVE/Syscall.pm |  1 +
 src/PVE/Tools.pm   | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/src/PVE/Syscall.pm b/src/PVE/Syscall.pm
index 2d5019f..10e185d 100644
--- a/src/PVE/Syscall.pm
+++ b/src/PVE/Syscall.pm
@@ -17,6 +17,7 @@ BEGIN {
 	setresuid => &SYS_setresuid,
 	fchownat => &SYS_fchownat,
 	mount => &SYS_mount,
+	renameat2 => &SYS_renameat2,
 
 	# These use asm-generic, so they're the same across (sane) architectures. We use numbers
 	# since they're not in perl's syscall.ph yet...
diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
index b4caf54..8d6734d 100644
--- a/src/PVE/Tools.pm
+++ b/src/PVE/Tools.pm
@@ -105,6 +105,11 @@ use constant {O_PATH    => 0x00200000,
 use constant {AT_EMPTY_PATH => 0x1000,
               AT_FDCWD => -100};
 
+# from <linux/fs.h>
+use constant {RENAME_NOREPLACE => (1 << 0),
+              RENAME_EXCHANGE  => (1 << 1),
+              RENAME_WHITEOUT  => (1 << 2)};
+
 sub run_with_timeout {
     my ($timeout, $code, @param) = @_;
 
@@ -1462,6 +1467,11 @@ sub fsync($) {
     return 0 == syscall(PVE::Syscall::fsync, $fileno);
 }
 
+sub renameat2($$$$$) {
+    my ($olddirfd, $oldpath, $newdirfd, $newpath, $flags) = @_;
+    return 0 == syscall(PVE::Syscall::renameat2, $olddirfd, $oldpath, $newdirfd, $newpath, $flags);
+}
+
 sub sync_mountpoint {
     my ($path) = @_;
     sysopen my $fd, $path, O_RDONLY|O_CLOEXEC or die "failed to open $path: $!\n";
-- 
2.39.2