proc: show file flags in fdinfo

Currently, there is an attempt to print FD flags, but
they are not decoded into a number, so we see something like this:

/criu # cat /proc/self/fdinfo/0
flags: {%!o(bool=000false)}

Actually, fdinfo has to contain file flags.

Change-Id: Idcbb7db908067447eb9ae6f2c3cfb861f2be1a97
PiperOrigin-RevId: 206794498

1 files changed, 16 insertions, 0 deletions

diff --git a/pkg/sentry/kernel/fd_map.go b/pkg/sentry/kernel/fd_map.go
index ef73125fd..299506330 100644
--- a/pkg/sentry/kernel/fd_map.go
+++ b/pkg/sentry/kernel/fd_map.go
@@ -51,6 +51,22 @@ type FDFlags struct {
 	CloseOnExec bool
 }
 
+// ToLinuxFileFlags converts a kernel.FDFlags object to a Linux file flags representation.
+func (f FDFlags) ToLinuxFileFlags() (mask uint) {
+	if f.CloseOnExec {
+		mask |= linux.O_CLOEXEC
+	}
+	return
+}
+
+// ToLinuxFDFlags converts a kernel.FDFlags object to a Linux descriptor flags representation.
+func (f FDFlags) ToLinuxFDFlags() (mask uint) {
+	if f.CloseOnExec {
+		mask |= linux.FD_CLOEXEC
+	}
+	return
+}
+
 // descriptor holds the details about a file descriptor, namely a pointer the
 // file itself and the descriptor flags.
 type descriptor struct {