diff options
Diffstat (limited to 'vendor/github.com/cilium/ebpf/btf/handle.go')
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/handle.go | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/btf/handle.go b/vendor/github.com/cilium/ebpf/btf/handle.go new file mode 100644 index 000000000..128e9b35c --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/handle.go @@ -0,0 +1,121 @@ +package btf + +import ( + "errors" + "fmt" + "os" + + "github.com/cilium/ebpf/internal/sys" + "github.com/cilium/ebpf/internal/unix" +) + +// HandleInfo describes a Handle. +type HandleInfo struct { + // ID of this handle in the kernel. The ID is only valid as long as the + // associated handle is kept alive. + ID ID + + // Name is an identifying name for the BTF, currently only used by the + // kernel. + Name string + + // IsKernel is true if the BTF originated with the kernel and not + // userspace. + IsKernel bool + + // Size of the raw BTF in bytes. + size uint32 +} + +func newHandleInfoFromFD(fd *sys.FD) (*HandleInfo, error) { + // We invoke the syscall once with a empty BTF and name buffers to get size + // information to allocate buffers. Then we invoke it a second time with + // buffers to receive the data. + var btfInfo sys.BtfInfo + if err := sys.ObjInfo(fd, &btfInfo); err != nil { + return nil, fmt.Errorf("get BTF info for fd %s: %w", fd, err) + } + + if btfInfo.NameLen > 0 { + // NameLen doesn't account for the terminating NUL. + btfInfo.NameLen++ + } + + // Don't pull raw BTF by default, since it may be quite large. + btfSize := btfInfo.BtfSize + btfInfo.BtfSize = 0 + + nameBuffer := make([]byte, btfInfo.NameLen) + btfInfo.Name, btfInfo.NameLen = sys.NewSlicePointerLen(nameBuffer) + if err := sys.ObjInfo(fd, &btfInfo); err != nil { + return nil, err + } + + return &HandleInfo{ + ID: ID(btfInfo.Id), + Name: unix.ByteSliceToString(nameBuffer), + IsKernel: btfInfo.KernelBtf != 0, + size: btfSize, + }, nil +} + +// IsModule returns true if the BTF is for the kernel itself. +func (i *HandleInfo) IsVmlinux() bool { + return i.IsKernel && i.Name == "vmlinux" +} + +// IsModule returns true if the BTF is for a kernel module. +func (i *HandleInfo) IsModule() bool { + return i.IsKernel && i.Name != "vmlinux" +} + +// HandleIterator allows enumerating BTF blobs loaded into the kernel. +type HandleIterator struct { + // The ID of the last retrieved handle. Only valid after a call to Next. + ID ID + err error +} + +// Next retrieves a handle for the next BTF blob. +// +// [Handle.Close] is called if *handle is non-nil to avoid leaking fds. +// +// Returns true if another BTF blob was found. Call [HandleIterator.Err] after +// the function returns false. +func (it *HandleIterator) Next(handle **Handle) bool { + if *handle != nil { + (*handle).Close() + *handle = nil + } + + id := it.ID + for { + attr := &sys.BtfGetNextIdAttr{Id: id} + err := sys.BtfGetNextId(attr) + if errors.Is(err, os.ErrNotExist) { + // There are no more BTF objects. + return false + } else if err != nil { + it.err = fmt.Errorf("get next BTF ID: %w", err) + return false + } + + id = attr.NextId + *handle, err = NewHandleFromID(id) + if errors.Is(err, os.ErrNotExist) { + // Try again with the next ID. + continue + } else if err != nil { + it.err = fmt.Errorf("retrieve handle for ID %d: %w", id, err) + return false + } + + it.ID = id + return true + } +} + +// Err returns an error if iteration failed for some reason. +func (it *HandleIterator) Err() error { + return it.err +} |