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Revert "Merge pull request 101888 from kolyshkin/update-runc-rc94"

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This reverts commit b1b06fe0a4, reversing
changes made to 382a33986b.
This commit is contained in:
Jordan Liggitt
2021-05-18 09:12:04 -04:00
parent 7ccd90e7d7
commit 4b45d0d921
336 changed files with 5393 additions and 17166 deletions
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253
vendor/github.com/cilium/ebpf/link/perf_event.go generated vendored
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@@ -1,253 +0,0 @@
package link
import (
"bytes"
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"regexp"
"runtime"
"strconv"
"strings"
"unsafe"
"github.com/cilium/ebpf"
"github.com/cilium/ebpf/internal"
"github.com/cilium/ebpf/internal/unix"
)
// Getting the terminology right is usually the hardest part. For posterity and
// for staying sane during implementation:
//
// - trace event: Representation of a kernel runtime hook. Filesystem entries
// under <tracefs>/events. Can be tracepoints (static), kprobes or uprobes.
// Can be instantiated into perf events (see below).
// - tracepoint: A predetermined hook point in the kernel. Exposed as trace
// events in (sub)directories under <tracefs>/events. Cannot be closed or
// removed, they are static.
// - k(ret)probe: Ephemeral trace events based on entry or exit points of
// exported kernel symbols. kprobe-based (tracefs) trace events can be
// created system-wide by writing to the <tracefs>/kprobe_events file, or
// they can be scoped to the current process by creating PMU perf events.
// - perf event: An object instantiated based on an existing trace event or
// kernel symbol. Referred to by fd in userspace.
// Exactly one eBPF program can be attached to a perf event. Multiple perf
// events can be created from a single trace event. Closing a perf event
// stops any further invocations of the attached eBPF program.
var (
tracefsPath = "/sys/kernel/debug/tracing"
// Trace event groups, names and kernel symbols must adhere to this set
// of characters. Non-empty, first character must not be a number, all
// characters must be alphanumeric or underscore.
rgxTraceEvent = regexp.MustCompile("^[a-zA-Z_][0-9a-zA-Z_]*$")
errInvalidInput = errors.New("invalid input")
)
const (
perfAllThreads = -1
)
// A perfEvent represents a perf event kernel object. Exactly one eBPF program
// can be attached to it. It is created based on a tracefs trace event or a
// Performance Monitoring Unit (PMU).
type perfEvent struct {
// Group and name of the tracepoint/kprobe/uprobe.
group string
name string
// PMU event ID read from sysfs. Valid IDs are non-zero.
pmuID uint64
// ID of the trace event read from tracefs. Valid IDs are non-zero.
tracefsID uint64
// True for kretprobes/uretprobes.
ret bool
fd *internal.FD
progType ebpf.ProgramType
}
func (pe *perfEvent) isLink() {}
func (pe *perfEvent) Pin(string) error {
return fmt.Errorf("pin perf event: %w", ErrNotSupported)
}
func (pe *perfEvent) Unpin() error {
return fmt.Errorf("unpin perf event: %w", ErrNotSupported)
}
// Since 4.15 (e87c6bc3852b "bpf: permit multiple bpf attachments for a single perf event"),
// calling PERF_EVENT_IOC_SET_BPF appends the given program to a prog_array
// owned by the perf event, which means multiple programs can be attached
// simultaneously.
//
// Before 4.15, calling PERF_EVENT_IOC_SET_BPF more than once on a perf event
// returns EEXIST.
//
// Detaching a program from a perf event is currently not possible, so a
// program replacement mechanism cannot be implemented for perf events.
func (pe *perfEvent) Update(prog *ebpf.Program) error {
return fmt.Errorf("can't replace eBPF program in perf event: %w", ErrNotSupported)
}
func (pe *perfEvent) Close() error {
if pe.fd == nil {
return nil
}
pfd, err := pe.fd.Value()
if err != nil {
return fmt.Errorf("getting perf event fd: %w", err)
}
err = unix.IoctlSetInt(int(pfd), unix.PERF_EVENT_IOC_DISABLE, 0)
if err != nil {
return fmt.Errorf("disabling perf event: %w", err)
}
err = pe.fd.Close()
if err != nil {
return fmt.Errorf("closing perf event fd: %w", err)
}
switch t := pe.progType; t {
case ebpf.Kprobe:
// For kprobes created using tracefs, clean up the <tracefs>/kprobe_events entry.
if pe.tracefsID != 0 {
return closeTraceFSKprobeEvent(pe.group, pe.name)
}
case ebpf.TracePoint:
// Tracepoint trace events don't hold any extra resources.
return nil
}
return nil
}
// attach the given eBPF prog to the perf event stored in pe.
// pe must contain a valid perf event fd.
// prog's type must match the program type stored in pe.
func (pe *perfEvent) attach(prog *ebpf.Program) error {
if prog == nil {
return errors.New("cannot attach a nil program")
}
if pe.fd == nil {
return errors.New("cannot attach to nil perf event")
}
if t := prog.Type(); t != pe.progType {
return fmt.Errorf("invalid program type (expected %s): %s", pe.progType, t)
}
if prog.FD() < 0 {
return fmt.Errorf("invalid program: %w", internal.ErrClosedFd)
}
// The ioctl below will fail when the fd is invalid.
kfd, _ := pe.fd.Value()
// Assign the eBPF program to the perf event.
err := unix.IoctlSetInt(int(kfd), unix.PERF_EVENT_IOC_SET_BPF, prog.FD())
if err != nil {
return fmt.Errorf("setting perf event bpf program: %w", err)
}
// PERF_EVENT_IOC_ENABLE and _DISABLE ignore their given values.
if err := unix.IoctlSetInt(int(kfd), unix.PERF_EVENT_IOC_ENABLE, 0); err != nil {
return fmt.Errorf("enable perf event: %s", err)
}
// Close the perf event when its reference is lost to avoid leaking system resources.
runtime.SetFinalizer(pe, (*perfEvent).Close)
return nil
}
// unsafeStringPtr returns an unsafe.Pointer to a NUL-terminated copy of str.
func unsafeStringPtr(str string) (unsafe.Pointer, error) {
p, err := unix.BytePtrFromString(str)
if err != nil {
return nil, err
}
return unsafe.Pointer(p), nil
}
// getTraceEventID reads a trace event's ID from tracefs given its group and name.
// group and name must be alphanumeric or underscore, as required by the kernel.
func getTraceEventID(group, name string) (uint64, error) {
tid, err := uint64FromFile(tracefsPath, "events", group, name, "id")
if errors.Is(err, ErrNotSupported) {
return 0, fmt.Errorf("trace event %s/%s: %w", group, name, ErrNotSupported)
}
if err != nil {
return 0, fmt.Errorf("reading trace event ID of %s/%s: %w", group, name, err)
}
return tid, nil
}
// getPMUEventType reads a Performance Monitoring Unit's type (numeric identifier)
// from /sys/bus/event_source/devices/<pmu>/type.
func getPMUEventType(pmu string) (uint64, error) {
et, err := uint64FromFile("/sys/bus/event_source/devices", pmu, "type")
if errors.Is(err, ErrNotSupported) {
return 0, fmt.Errorf("pmu type %s: %w", pmu, ErrNotSupported)
}
if err != nil {
return 0, fmt.Errorf("reading pmu type %s: %w", pmu, err)
}
return et, nil
}
// openTracepointPerfEvent opens a tracepoint-type perf event. System-wide
// kprobes created by writing to <tracefs>/kprobe_events are tracepoints
// behind the scenes, and can be attached to using these perf events.
func openTracepointPerfEvent(tid uint64) (*internal.FD, error) {
attr := unix.PerfEventAttr{
Type: unix.PERF_TYPE_TRACEPOINT,
Config: tid,
Sample_type: unix.PERF_SAMPLE_RAW,
Sample: 1,
Wakeup: 1,
}
fd, err := unix.PerfEventOpen(&attr, perfAllThreads, 0, -1, unix.PERF_FLAG_FD_CLOEXEC)
if err != nil {
return nil, fmt.Errorf("opening tracepoint perf event: %w", err)
}
return internal.NewFD(uint32(fd)), nil
}
// uint64FromFile reads a uint64 from a file. All elements of path are sanitized
// and joined onto base. Returns error if base no longer prefixes the path after
// joining all components.
func uint64FromFile(base string, path ...string) (uint64, error) {
// Resolve leaf path separately for error feedback. Makes the join onto
// base more readable (can't mix with variadic args).
l := filepath.Join(path...)
p := filepath.Join(base, l)
if !strings.HasPrefix(p, base) {
return 0, fmt.Errorf("path '%s' attempts to escape base path '%s': %w", l, base, errInvalidInput)
}
data, err := ioutil.ReadFile(p)
if os.IsNotExist(err) {
// Only echo leaf path, the base path can be prepended at the call site
// if more verbosity is required.
return 0, fmt.Errorf("symbol %s: %w", l, ErrNotSupported)
}
if err != nil {
return 0, fmt.Errorf("reading file %s: %w", p, err)
}
et := bytes.TrimSpace(data)
return strconv.ParseUint(string(et), 10, 64)
}