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|
package internal
import (
"fmt"
"sync"
"github.com/cilium/ebpf/internal/unix"
)
const (
// Version constant used in ELF binaries indicating that the loader needs to
// substitute the eBPF program's version with the value of the kernel's
// KERNEL_VERSION compile-time macro. Used for compatibility with BCC, gobpf
// and RedSift.
MagicKernelVersion = 0xFFFFFFFE
)
var (
kernelVersion = struct {
once sync.Once
version Version
err error
}{}
)
// A Version in the form Major.Minor.Patch.
type Version [3]uint16
// NewVersion creates a version from a string like "Major.Minor.Patch".
//
// Patch is optional.
func NewVersion(ver string) (Version, error) {
var major, minor, patch uint16
n, _ := fmt.Sscanf(ver, "%d.%d.%d", &major, &minor, &patch)
if n < 2 {
return Version{}, fmt.Errorf("invalid version: %s", ver)
}
return Version{major, minor, patch}, nil
}
// NewVersionFromCode creates a version from a LINUX_VERSION_CODE.
func NewVersionFromCode(code uint32) Version {
return Version{
uint16(uint8(code >> 16)),
uint16(uint8(code >> 8)),
uint16(uint8(code)),
}
}
func (v Version) String() string {
if v[2] == 0 {
return fmt.Sprintf("v%d.%d", v[0], v[1])
}
return fmt.Sprintf("v%d.%d.%d", v[0], v[1], v[2])
}
// Less returns true if the version is less than another version.
func (v Version) Less(other Version) bool {
for i, a := range v {
if a == other[i] {
continue
}
return a < other[i]
}
return false
}
// Unspecified returns true if the version is all zero.
func (v Version) Unspecified() bool {
return v[0] == 0 && v[1] == 0 && v[2] == 0
}
// Kernel implements the kernel's KERNEL_VERSION macro from linux/version.h.
// It represents the kernel version and patch level as a single value.
func (v Version) Kernel() uint32 {
// Kernels 4.4 and 4.9 have their SUBLEVEL clamped to 255 to avoid
// overflowing into PATCHLEVEL.
// See kernel commit 9b82f13e7ef3 ("kbuild: clamp SUBLEVEL to 255").
s := v[2]
if s > 255 {
s = 255
}
// Truncate members to uint8 to prevent them from spilling over into
// each other when overflowing 8 bits.
return uint32(uint8(v[0]))<<16 | uint32(uint8(v[1]))<<8 | uint32(uint8(s))
}
// KernelVersion returns the version of the currently running kernel.
func KernelVersion() (Version, error) {
kernelVersion.once.Do(func() {
kernelVersion.version, kernelVersion.err = detectKernelVersion()
})
if kernelVersion.err != nil {
return Version{}, kernelVersion.err
}
return kernelVersion.version, nil
}
// detectKernelVersion returns the version of the running kernel.
func detectKernelVersion() (Version, error) {
vc, err := vdsoVersion()
if err != nil {
return Version{}, err
}
return NewVersionFromCode(vc), nil
}
// KernelRelease returns the release string of the running kernel.
// Its format depends on the Linux distribution and corresponds to directory
// names in /lib/modules by convention. Some examples are 5.15.17-1-lts and
// 4.19.0-16-amd64.
func KernelRelease() (string, error) {
var uname unix.Utsname
if err := unix.Uname(&uname); err != nil {
return "", fmt.Errorf("uname failed: %w", err)
}
return unix.ByteSliceToString(uname.Release[:]), nil
}
|
