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-rw-r--r--pkg/sentry/fsimpl/proc/tasks.go102
-rw-r--r--pkg/sentry/fsimpl/proc/tasks_test.go147
2 files changed, 223 insertions, 26 deletions
diff --git a/pkg/sentry/fsimpl/proc/tasks.go b/pkg/sentry/fsimpl/proc/tasks.go
index 50b2a832f..d8f92d52f 100644
--- a/pkg/sentry/fsimpl/proc/tasks.go
+++ b/pkg/sentry/fsimpl/proc/tasks.go
@@ -27,7 +27,11 @@ import (
"gvisor.dev/gvisor/pkg/syserror"
)
-const defaultPermission = 0444
+const (
+ defaultPermission = 0444
+ selfName = "self"
+ threadSelfName = "thread-self"
+)
// InoGenerator generates unique inode numbers for a given filesystem.
type InoGenerator interface {
@@ -45,6 +49,11 @@ type tasksInode struct {
inoGen InoGenerator
pidns *kernel.PIDNamespace
+
+ // '/proc/self' and '/proc/thread-self' have custom directory offsets in
+ // Linux. So handle them outside of OrderedChildren.
+ selfSymlink *vfs.Dentry
+ threadSelfSymlink *vfs.Dentry
}
var _ kernfs.Inode = (*tasksInode)(nil)
@@ -54,20 +63,20 @@ func newTasksInode(inoGen InoGenerator, k *kernel.Kernel, pidns *kernel.PIDNames
contents := map[string]*kernfs.Dentry{
//"cpuinfo": newCPUInfo(ctx, msrc),
//"filesystems": seqfile.NewSeqFileInode(ctx, &filesystemsData{}, msrc),
- "loadavg": newDentry(root, inoGen.NextIno(), defaultPermission, &loadavgData{}),
- "meminfo": newDentry(root, inoGen.NextIno(), defaultPermission, &meminfoData{k: k}),
- "mounts": kernfs.NewStaticSymlink(root, inoGen.NextIno(), defaultPermission, "self/mounts"),
- "self": newSelfSymlink(root, inoGen.NextIno(), defaultPermission, pidns),
- "stat": newDentry(root, inoGen.NextIno(), defaultPermission, &statData{k: k}),
- "thread-self": newThreadSelfSymlink(root, inoGen.NextIno(), defaultPermission, pidns),
+ "loadavg": newDentry(root, inoGen.NextIno(), defaultPermission, &loadavgData{}),
+ "meminfo": newDentry(root, inoGen.NextIno(), defaultPermission, &meminfoData{k: k}),
+ "mounts": kernfs.NewStaticSymlink(root, inoGen.NextIno(), defaultPermission, "self/mounts"),
+ "stat": newDentry(root, inoGen.NextIno(), defaultPermission, &statData{k: k}),
//"uptime": newUptime(ctx, msrc),
//"version": newVersionData(root, inoGen.NextIno(), k),
"version": newDentry(root, inoGen.NextIno(), defaultPermission, &versionData{k: k}),
}
inode := &tasksInode{
- pidns: pidns,
- inoGen: inoGen,
+ pidns: pidns,
+ inoGen: inoGen,
+ selfSymlink: newSelfSymlink(root, inoGen.NextIno(), 0444, pidns).VFSDentry(),
+ threadSelfSymlink: newThreadSelfSymlink(root, inoGen.NextIno(), 0444, pidns).VFSDentry(),
}
inode.InodeAttrs.Init(root, inoGen.NextIno(), linux.ModeDirectory|0555)
@@ -86,6 +95,13 @@ func (i *tasksInode) Lookup(ctx context.Context, name string) (*vfs.Dentry, erro
// Try to lookup a corresponding task.
tid, err := strconv.ParseUint(name, 10, 64)
if err != nil {
+ // If it failed to parse, check if it's one of the special handled files.
+ switch name {
+ case selfName:
+ return i.selfSymlink, nil
+ case threadSelfName:
+ return i.threadSelfSymlink, nil
+ }
return nil, syserror.ENOENT
}
@@ -104,41 +120,81 @@ func (i *tasksInode) Valid(ctx context.Context) bool {
}
// IterDirents implements kernfs.inodeDynamicLookup.
-//
-// TODO(gvisor.dev/issue/1195): Use tgid N offset = TGID_OFFSET + N.
-func (i *tasksInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, offset, relOffset int64) (int64, error) {
- var tids []int
+func (i *tasksInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, offset, _ int64) (int64, error) {
+ // fs/proc/internal.h: #define FIRST_PROCESS_ENTRY 256
+ const FIRST_PROCESS_ENTRY = 256
+
+ // Use maxTaskID to shortcut searches that will result in 0 entries.
+ const maxTaskID = kernel.TasksLimit + 1
+ if offset >= maxTaskID {
+ return offset, nil
+ }
+
+ // According to Linux (fs/proc/base.c:proc_pid_readdir()), process directories
+ // start at offset FIRST_PROCESS_ENTRY with '/proc/self', followed by
+ // '/proc/thread-self' and then '/proc/[pid]'.
+ if offset < FIRST_PROCESS_ENTRY {
+ offset = FIRST_PROCESS_ENTRY
+ }
+
+ if offset == FIRST_PROCESS_ENTRY {
+ dirent := vfs.Dirent{
+ Name: selfName,
+ Type: linux.DT_LNK,
+ Ino: i.inoGen.NextIno(),
+ NextOff: offset + 1,
+ }
+ if !cb.Handle(dirent) {
+ return offset, nil
+ }
+ offset++
+ }
+ if offset == FIRST_PROCESS_ENTRY+1 {
+ dirent := vfs.Dirent{
+ Name: threadSelfName,
+ Type: linux.DT_LNK,
+ Ino: i.inoGen.NextIno(),
+ NextOff: offset + 1,
+ }
+ if !cb.Handle(dirent) {
+ return offset, nil
+ }
+ offset++
+ }
- // Collect all tasks. Per linux we only include it in directory listings if
- // it's the leader. But for whatever crazy reason, you can still walk to the
- // given node.
+ // Collect all tasks that TGIDs are greater than the offset specified. Per
+ // Linux we only include in directory listings if it's the leader. But for
+ // whatever crazy reason, you can still walk to the given node.
+ var tids []int
+ startTid := offset - FIRST_PROCESS_ENTRY - 2
for _, tg := range i.pidns.ThreadGroups() {
+ tid := i.pidns.IDOfThreadGroup(tg)
+ if int64(tid) < startTid {
+ continue
+ }
if leader := tg.Leader(); leader != nil {
- tids = append(tids, int(i.pidns.IDOfThreadGroup(tg)))
+ tids = append(tids, int(tid))
}
}
if len(tids) == 0 {
return offset, nil
}
- if relOffset >= int64(len(tids)) {
- return offset, nil
- }
sort.Ints(tids)
- for _, tid := range tids[relOffset:] {
+ for _, tid := range tids {
dirent := vfs.Dirent{
Name: strconv.FormatUint(uint64(tid), 10),
Type: linux.DT_DIR,
Ino: i.inoGen.NextIno(),
- NextOff: offset + 1,
+ NextOff: FIRST_PROCESS_ENTRY + 2 + int64(tid) + 1,
}
if !cb.Handle(dirent) {
return offset, nil
}
offset++
}
- return offset, nil
+ return maxTaskID, nil
}
// Open implements kernfs.Inode.
diff --git a/pkg/sentry/fsimpl/proc/tasks_test.go b/pkg/sentry/fsimpl/proc/tasks_test.go
index 2560fcef9..ca8c87ec2 100644
--- a/pkg/sentry/fsimpl/proc/tasks_test.go
+++ b/pkg/sentry/fsimpl/proc/tasks_test.go
@@ -16,6 +16,7 @@ package proc
import (
"fmt"
+ "math"
"path"
"strconv"
"testing"
@@ -30,6 +31,18 @@ import (
"gvisor.dev/gvisor/pkg/syserror"
)
+var (
+ // Next offset 256 by convention. Adds 1 for the next offset.
+ selfLink = vfs.Dirent{Type: linux.DT_LNK, NextOff: 256 + 0 + 1}
+ threadSelfLink = vfs.Dirent{Type: linux.DT_LNK, NextOff: 256 + 1 + 1}
+
+ // /proc/[pid] next offset starts at 256+2 (files above), then adds the
+ // PID, and adds 1 for the next offset.
+ proc1 = vfs.Dirent{Type: linux.DT_DIR, NextOff: 258 + 1 + 1}
+ proc2 = vfs.Dirent{Type: linux.DT_DIR, NextOff: 258 + 2 + 1}
+ proc3 = vfs.Dirent{Type: linux.DT_DIR, NextOff: 258 + 3 + 1}
+)
+
type testIterDirentsCallback struct {
dirents []vfs.Dirent
}
@@ -59,9 +72,9 @@ func checkTasksStaticFiles(gots []vfs.Dirent) ([]vfs.Dirent, error) {
"loadavg": {Type: linux.DT_REG},
"meminfo": {Type: linux.DT_REG},
"mounts": {Type: linux.DT_LNK},
- "self": {Type: linux.DT_LNK},
+ "self": selfLink,
"stat": {Type: linux.DT_REG},
- "thread-self": {Type: linux.DT_LNK},
+ "thread-self": threadSelfLink,
"version": {Type: linux.DT_REG},
}
return checkFiles(gots, wants)
@@ -93,6 +106,9 @@ func checkFiles(gots []vfs.Dirent, wants map[string]vfs.Dirent) ([]vfs.Dirent, e
if want.Type != got.Type {
return gots, fmt.Errorf("wrong file type, want: %v, got: %v: %+v", want.Type, got.Type, got)
}
+ if want.NextOff != 0 && want.NextOff != got.NextOff {
+ return gots, fmt.Errorf("wrong dirent offset, want: %v, got: %v: %+v", want.NextOff, got.NextOff, got)
+ }
delete(wants, got.Name)
gots = append(gots[0:i], gots[i+1:]...)
@@ -154,7 +170,7 @@ func TestTasksEmpty(t *testing.T) {
t.Error(err.Error())
}
if len(cb.dirents) != 0 {
- t.Error("found more files than expected: %+v", cb.dirents)
+ t.Errorf("found more files than expected: %+v", cb.dirents)
}
}
@@ -216,6 +232,11 @@ func TestTasks(t *testing.T) {
if !found {
t.Errorf("Additional task ID %d listed: %v", pid, tasks)
}
+ // Next offset starts at 256+2 ('self' and 'thread-self'), then adds the
+ // PID, and adds 1 for the next offset.
+ if want := int64(256 + 2 + pid + 1); d.NextOff != want {
+ t.Errorf("Wrong dirent offset want: %d got: %d: %+v", want, d.NextOff, d)
+ }
}
// Test lookup.
@@ -246,6 +267,126 @@ func TestTasks(t *testing.T) {
}
}
+func TestTasksOffset(t *testing.T) {
+ ctx, vfsObj, root, err := setup()
+ if err != nil {
+ t.Fatalf("Setup failed: %v", err)
+ }
+ defer root.DecRef()
+
+ k := kernel.KernelFromContext(ctx)
+ for i := 0; i < 3; i++ {
+ tc := k.NewThreadGroup(nil, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, k.GlobalInit().Limits())
+ if _, err := createTask(ctx, fmt.Sprintf("name-%d", i), tc); err != nil {
+ t.Fatalf("CreateTask(): %v", err)
+ }
+ }
+
+ for _, tc := range []struct {
+ name string
+ offset int64
+ wants map[string]vfs.Dirent
+ }{
+ {
+ name: "small offset",
+ offset: 100,
+ wants: map[string]vfs.Dirent{
+ "self": selfLink,
+ "thread-self": threadSelfLink,
+ "1": proc1,
+ "2": proc2,
+ "3": proc3,
+ },
+ },
+ {
+ name: "offset at start",
+ offset: 256,
+ wants: map[string]vfs.Dirent{
+ "self": selfLink,
+ "thread-self": threadSelfLink,
+ "1": proc1,
+ "2": proc2,
+ "3": proc3,
+ },
+ },
+ {
+ name: "skip /proc/self",
+ offset: 257,
+ wants: map[string]vfs.Dirent{
+ "thread-self": threadSelfLink,
+ "1": proc1,
+ "2": proc2,
+ "3": proc3,
+ },
+ },
+ {
+ name: "skip symlinks",
+ offset: 258,
+ wants: map[string]vfs.Dirent{
+ "1": proc1,
+ "2": proc2,
+ "3": proc3,
+ },
+ },
+ {
+ name: "skip first process",
+ offset: 260,
+ wants: map[string]vfs.Dirent{
+ "2": proc2,
+ "3": proc3,
+ },
+ },
+ {
+ name: "last process",
+ offset: 261,
+ wants: map[string]vfs.Dirent{
+ "3": proc3,
+ },
+ },
+ {
+ name: "after last",
+ offset: 262,
+ wants: nil,
+ },
+ {
+ name: "TaskLimit+1",
+ offset: kernel.TasksLimit + 1,
+ wants: nil,
+ },
+ {
+ name: "max",
+ offset: math.MaxInt64,
+ wants: nil,
+ },
+ } {
+ t.Run(tc.name, func(t *testing.T) {
+ fd, err := vfsObj.OpenAt(
+ ctx,
+ auth.CredentialsFromContext(ctx),
+ &vfs.PathOperation{Root: root, Start: root, Path: fspath.Parse("/")},
+ &vfs.OpenOptions{},
+ )
+ if err != nil {
+ t.Fatalf("vfsfs.OpenAt(/) failed: %v", err)
+ }
+ if _, err := fd.Impl().Seek(ctx, tc.offset, linux.SEEK_SET); err != nil {
+ t.Fatalf("Seek(%d, SEEK_SET): %v", tc.offset, err)
+ }
+
+ cb := testIterDirentsCallback{}
+ if err := fd.Impl().IterDirents(ctx, &cb); err != nil {
+ t.Fatalf("IterDirents(): %v", err)
+ }
+ if cb.dirents, err = checkFiles(cb.dirents, tc.wants); err != nil {
+ t.Error(err.Error())
+ }
+ if len(cb.dirents) != 0 {
+ t.Errorf("found more files than expected: %+v", cb.dirents)
+ }
+ })
+ }
+}
+
func TestTask(t *testing.T) {
ctx, vfsObj, root, err := setup()
if err != nil {
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 08:08:37 +0000