Add remaining /proc/* and /proc/sys/* files

Except for one under /proc/sys/net/ipv4/tcp_sack.
/proc/pid/* is still incomplete.

Updates #1195

PiperOrigin-RevId: 290120438

1 files changed, 143 insertions, 0 deletions

diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go
new file mode 100644
index 000000000..aabf2bf0c
--- /dev/null
+++ b/pkg/sentry/fsimpl/proc/tasks_sys.go
@@ -0,0 +1,143 @@
+// Copyright 2019 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package proc
+
+import (
+	"bytes"
+	"fmt"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+)
+
+// newSysDir returns the dentry corresponding to /proc/sys directory.
+func newSysDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry {
+	return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+		"kernel": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+			"hostname": newDentry(root, inoGen.NextIno(), 0444, &hostnameData{}),
+			"shmall":   newDentry(root, inoGen.NextIno(), 0444, shmData(linux.SHMALL)),
+			"shmmax":   newDentry(root, inoGen.NextIno(), 0444, shmData(linux.SHMMAX)),
+			"shmmni":   newDentry(root, inoGen.NextIno(), 0444, shmData(linux.SHMMNI)),
+		}),
+		"vm": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+			"mmap_min_addr":     newDentry(root, inoGen.NextIno(), 0444, &mmapMinAddrData{}),
+			"overcommit_memory": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0\n")),
+		}),
+		"net": newSysNetDir(root, inoGen),
+	})
+}
+
+// newSysNetDir returns the dentry corresponding to /proc/sys/net directory.
+func newSysNetDir(root *auth.Credentials, inoGen InoGenerator) *kernfs.Dentry {
+	return kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+		"net": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+			"ipv4": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+				// Add tcp_sack.
+				// TODO(gvisor.dev/issue/1195): tcp_sack allows write(2)
+				// "tcp_sack": newTCPSackInode(ctx, msrc, s),
+
+				// The following files are simple stubs until they are implemented in
+				// netstack, most of these files are configuration related. We use the
+				// value closest to the actual netstack behavior or any empty file, all
+				// of these files will have mode 0444 (read-only for all users).
+				"ip_local_port_range":     newDentry(root, inoGen.NextIno(), 0444, newStaticFile("16000   65535")),
+				"ip_local_reserved_ports": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("")),
+				"ipfrag_time":             newDentry(root, inoGen.NextIno(), 0444, newStaticFile("30")),
+				"ip_nonlocal_bind":        newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"ip_no_pmtu_disc":         newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")),
+
+				// tcp_allowed_congestion_control tell the user what they are able to
+				// do as an unprivledged process so we leave it empty.
+				"tcp_allowed_congestion_control":   newDentry(root, inoGen.NextIno(), 0444, newStaticFile("")),
+				"tcp_available_congestion_control": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("reno")),
+				"tcp_congestion_control":           newDentry(root, inoGen.NextIno(), 0444, newStaticFile("reno")),
+
+				// Many of the following stub files are features netstack doesn't
+				// support. The unsupported features return "0" to indicate they are
+				// disabled.
+				"tcp_base_mss":              newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1280")),
+				"tcp_dsack":                 newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_early_retrans":         newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_fack":                  newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_fastopen":              newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_fastopen_key":          newDentry(root, inoGen.NextIno(), 0444, newStaticFile("")),
+				"tcp_invalid_ratelimit":     newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_keepalive_intvl":       newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_keepalive_probes":      newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_keepalive_time":        newDentry(root, inoGen.NextIno(), 0444, newStaticFile("7200")),
+				"tcp_mtu_probing":           newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_no_metrics_save":       newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")),
+				"tcp_probe_interval":        newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_probe_threshold":       newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"tcp_retries1":              newDentry(root, inoGen.NextIno(), 0444, newStaticFile("3")),
+				"tcp_retries2":              newDentry(root, inoGen.NextIno(), 0444, newStaticFile("15")),
+				"tcp_rfc1337":               newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")),
+				"tcp_slow_start_after_idle": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")),
+				"tcp_synack_retries":        newDentry(root, inoGen.NextIno(), 0444, newStaticFile("5")),
+				"tcp_syn_retries":           newDentry(root, inoGen.NextIno(), 0444, newStaticFile("3")),
+				"tcp_timestamps":            newDentry(root, inoGen.NextIno(), 0444, newStaticFile("1")),
+			}),
+			"core": kernfs.NewStaticDir(root, inoGen.NextIno(), 0555, map[string]*kernfs.Dentry{
+				"default_qdisc": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("pfifo_fast")),
+				"message_burst": newDentry(root, inoGen.NextIno(), 0444, newStaticFile("10")),
+				"message_cost":  newDentry(root, inoGen.NextIno(), 0444, newStaticFile("5")),
+				"optmem_max":    newDentry(root, inoGen.NextIno(), 0444, newStaticFile("0")),
+				"rmem_default":  newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")),
+				"rmem_max":      newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")),
+				"somaxconn":     newDentry(root, inoGen.NextIno(), 0444, newStaticFile("128")),
+				"wmem_default":  newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")),
+				"wmem_max":      newDentry(root, inoGen.NextIno(), 0444, newStaticFile("212992")),
+			}),
+		}),
+	})
+}
+
+// mmapMinAddrData implements vfs.DynamicBytesSource for
+// /proc/sys/vm/mmap_min_addr.
+//
+// +stateify savable
+type mmapMinAddrData struct {
+	kernfs.DynamicBytesFile
+
+	k *kernel.Kernel
+}
+
+var _ dynamicInode = (*mmapMinAddrData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (d *mmapMinAddrData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	fmt.Fprintf(buf, "%d\n", d.k.Platform.MinUserAddress())
+	return nil
+}
+
+// hostnameData implements vfs.DynamicBytesSource for /proc/sys/kernel/hostname.
+//
+// +stateify savable
+type hostnameData struct {
+	kernfs.DynamicBytesFile
+}
+
+var _ dynamicInode = (*hostnameData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.Generate.
+func (*hostnameData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	utsns := kernel.UTSNamespaceFromContext(ctx)
+	buf.WriteString(utsns.HostName())
+	buf.WriteString("\n")
+	return nil
+}