Class: RbBCC::BCC

Inherits:
Object
  • Object
show all
Defined in:
lib/rbbcc/bcc.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(text: "", src_file: nil, hdr_file: nil, debug: 0, cflags: [], usdt_contexts: [], allow_rlimit: 0, dev_name: nil) ⇒ BCC

Returns a new instance of BCC.



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# File 'lib/rbbcc/bcc.rb', line 223

def initialize(text: "", src_file: nil, hdr_file: nil, debug: 0, cflags: [], usdt_contexts: [], allow_rlimit: 0, dev_name: nil)
  @kprobe_fds = {}
  @uprobe_fds = {}
  @tracepoint_fds = {}
  @raw_tracepoint_fds = {}

  if src_file
    src_file = BCC._find_file(src_file)
    hdr_file = BCC._find_file(hdr_file)
  end

  if src_file && src_file.end_with?(".b")
    @module = Clib.bpf_module_create_b(src_file, hdr_file, debug, dev_name)
  else
    if src_file
      text = File.read(src_file)
    end

    @usdt_contexts = usdt_contexts
    if code = gen_args_from_usdt
      text = code + text
    end


    cflags_safe = if cflags.empty? or !cflags[-1].nil?
                    cflags + [nil]
                  else
                    cflags
                  end

    @module = Clib.do_bpf_module_create_c_from_string(
      text,
      debug,
      cflags_safe.pack("p*"),
      cflags_safe.size,
      allow_rlimit,
      dev_name
    )
  end
  @funcs = {}
  @tables = {}
  @perf_buffers = {}

  unless @module
    raise "BPF module not created"
  end

  trace_autoload!

  @usdt_contexts.each do |usdt|
    usdt.enumerate_active_probes.each do |probe|
      attach_uprobe(name: probe.binpath, fn_name: probe.fn_name, addr: probe.addr, pid: probe.pid)
    end
  end

  at_exit { self.cleanup }
end

Instance Attribute Details

#module ⇒ Object (readonly)

Returns the value of attribute module.



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# File 'lib/rbbcc/bcc.rb', line 280

def module
  @module
end

#perf_buffers ⇒ Object (readonly)

Returns the value of attribute perf_buffers.



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# File 'lib/rbbcc/bcc.rb', line 280

def perf_buffers
  @perf_buffers
end

#tables ⇒ Object (readonly)

Returns the value of attribute tables.



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# File 'lib/rbbcc/bcc.rb', line 521

def tables
  @tables
end

Class Method Details

._find_file(filename) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 18

def _find_file(filename)
  if filename
    unless File.exist?(filename)
      t = File.expand_path "../#{filename}", $0
      if File.exist?(t)
        filename = t
      else
        raise "Could not find file #{filename}"
      end
    end
  end
  return filename
end

.attach_raw_socket(fn, dev) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 205

def attach_raw_socket(fn, dev)
  unless fn.is_a?(Hash)
    raise "arg 1 must be of BPF.Function Hash"
  end
  sock = Clib.bpf_open_raw_sock(dev)
  if sock < 0
    raise SystemCallError.new("Failed to open raw device %s" % dev, Fiddle.last_error)
  end

  res = Clib.bpf_attach_socket(sock, fn[:fd])
  if res < 0
    raise SystemCallError.new("Failed to attach BPF to device %s" % dev, Fiddle.last_error)
  end
  fn[:sock] = sock
  fn
end

.check_path_symbol(module_, symname, addr, pid) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 110

def check_path_symbol(module_, symname, addr, pid)
  sym = Clib::BCCSymbol.malloc
  c_pid = pid == -1 ? 0 : pid
  if Clib.bcc_resolve_symname(module_, symname, (addr || 0x0), c_pid, nil, sym) < 0
    raise("could not determine address of symbol %s" % symname)
  end
  module_path = Clib.__extract_char sym.module
  # XXX: need to free char* in ruby ffi?
  Clib.bcc_procutils_free(sym.module)
  return module_path, sym.offset
end

.decode_table_type(desc) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 122

def decode_table_type(desc)
  return desc if desc.is_a?(String)
  anon = []
  fields = []
  # e.g. ["bpf_stacktrace", [["ip", "unsigned long long", [127]]], "struct_packed"]
  name, typedefs, data_type = desc
  typedefs.each do |field|
    case field.size
    when 2
      fields << "#{decode_table_type(field[1])} #{field[0]}"
    when 3
      ftype = field.last
      if ftype.is_a?(Array)
        fields << "#{decode_table_type(field[1])}[#{ftype[0]}] #{field[0]}"
      elsif ftype.is_a?(Integer)
        warn("Warning: Ruby fiddle does not support bitfield member, ignoring")
        warn("Adding member `#{field[1]} #{field[0]}:#{ftype}'")
        fields << "#{decode_table_type(field[1])} #{field[0]}"
      elsif %w(union struct struct_packed).in?(ftype)
        name = field[0]
        if name.empty?
          name = "__anon%d" % anon.size
          anon << name
        end
        # FIXME: nested struct
        fields << "#{decode_table_type(field)} #{name}"
      else
        raise("Failed to decode type #{field.inspect}")
      end
    else
      raise("Failed to decode type #{field.inspect}")
    end
  end
  c = nil
  if data_type == "union"
    c = Fiddle::Importer.union(fields)
  else
    c = Fiddle::Importer.struct(fields)
  end

  fields.each do |field|
    md = /^char\[(\d+)\] ([_a-zA-Z0-9]+)/.match(field)
    if md
      c.alias_method "__super_#{md[2]}", md[2]
      c.define_method md[2] do
        # Split the char[] in the place where the first \0 appears
        raw = __send__("__super_#{md[2]}")
        raw = raw[0...raw.index(0)] if raw.index(0)
        raw.pack("c*")
      end
    end
  end

  c.define_singleton_method :original_desc do
    desc
  end
  c.define_singleton_method :fields do
    fields
  end
  orig_name = c.inspect
  c.define_singleton_method :inspect do
    orig_name.sub /(?=>$)/, " original_desc=#{desc.inspect}" rescue super
  end
  c
end

.get_kprobe_functions(event_re) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 46

def get_kprobe_functions(event_re)
  blacklist = []
  fns = []
  File.open(File.expand_path("../kprobes/blacklist", TRACEFS), "rb") do |blacklist_f|
    blacklist = blacklist_f.each_line.map { |line|
      line.rstrip.split[1]
    }.uniq
  end
  in_init_section = 0
  in_irq_section = 0
  File.open("/proc/kallsyms", "rb") do |avail_file|
    avail_file.each_line do |line|
      t, fn = line.rstrip.split[1,2]
      # Skip all functions defined between __init_begin and
      # __init_end
      if in_init_section == 0
        if fn == '__init_begin'
          in_init_section = 1
          next
        elsif in_init_section == 1
          if fn == '__init_end'
            in_init_section = 2
            next
          end
        end
        # Skip all functions defined between __irqentry_text_start and
        # __irqentry_text_end
        if in_irq_section == 0
          if fn == '__irqentry_text_start'
            in_irq_section = 1
            next
          elsif in_irq_section == 1
            if fn == '__irqentry_text_end'
              in_irq_section = 2
              next
            end
          end
        end
        # All functions defined as NOKPROBE_SYMBOL() start with the
        # prefix _kbl_addr_*, blacklisting them by looking at the name
        # allows to catch also those symbols that are defined in kernel
        # modules.
        if fn.start_with?('_kbl_addr_')
          next
        # Explicitly blacklist perf-related functions, they are all
        # non-attachable.
        elsif fn.start_with?('__perf') || fn.start_with?('perf_')
          next
        # Exclude all gcc 8's extra .cold functions
        elsif fn =~ /^.*\.cold\.\d+$/
          next
        end
        if %w(t w).include?(t.downcase) \
           && /#{event_re}/ =~ fn \
           && !blacklist.include?(fn)
          fns << fn
        end
      end
    end
  end
  fns = fns.uniq
  return fns.empty? ? nil : fns
end

.ksym(addr, show_module: false, show_offset: false) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 32

def ksym(addr, show_module: false, show_offset: false)
  self.sym(addr, -1, show_module: show_module, show_offset: show_offset, demangle: false)
end

.ksymname(name) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 36

def ksymname(name)
  SymbolCache.resolve_global(name)
end

.support_raw_tracepoint ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 40

def support_raw_tracepoint
  # kernel symbol "bpf_find_raw_tracepoint"
  # indicates raw_tracepint support
  ksymname("bpf_find_raw_tracepoint") || ksymname("bpf_get_raw_tracepoint")
end

.sym(addr, pid, show_module: false, show_offset: false, demangle: true) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 188

def sym(addr, pid, show_module: false, show_offset: false, demangle: true)
  # FIXME: case of typeofaddr.find('bpf_stack_build_id')
  #s = Clib::BCCSymbol.malloc
  #b = Clib::BCCStacktraceBuildID.malloc
  #b.status = addr.status
  #b.build_id = addr.build_id
  #b.u = addr.offset
  #Clib.bcc_buildsymcache_resolve(BPF.bsymcache, b, s)

  name, offset_, module_ = SymbolCache.cache(pid).resolve(addr, demangle)
  offset = (show_offset && name) ? ("+0x%x" % offset_) : ""
  name = name || "[unknown]"
  name = name + offset
  module_ = (show_module && module_) ? " [#{File.basename.basename(module_)}]" : ""
  return name + module_
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 542

def [](key)
  self.tables[key] ||= get_table(key)
end

#[]=(key, value) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 546

def []=(key, value)
  self.tables[key] = value
end

#attach_kprobe(event:, fn_name:, event_off: 0) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 339

def attach_kprobe(event:, fn_name:, event_off: 0)
  fn = load_func(fn_name, BPF::KPROBE)
  ev_name = "p_" + event.gsub(/[\+\.]/, "_")
  fd = Clib.bpf_attach_kprobe(fn[:fd], 0, ev_name, event, event_off, 0)
  if fd < 0
    raise SystemCallError.new("Failed to attach BPF program #{fn_name} to kprobe #{event}", Fiddle.last_error)
  end
  Util.debug "Attach: #{ev_name}"
  @kprobe_fds[ev_name] = fd
  [ev_name, fd]
end

#attach_kretprobe(event:, fn_name:, event_re: nil, maxactive: 0) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 351

def attach_kretprobe(event:, fn_name:, event_re: nil, maxactive: 0)
  # TODO: if event_re ...
  fn = load_func(fn_name, BPF::KPROBE)
  ev_name = "r_" + event.gsub(/[\+\.]/, "_")
  fd = Clib.bpf_attach_kprobe(fn[:fd], 1, ev_name, event, 0, maxactive)
  if fd < 0
    raise SystemCallError.new("Failed to attach BPF program #{fn_name} to kretprobe #{event}", Fiddle.last_error)
  end
  Util.debug "Attach: #{ev_name}"
  @kprobe_fds[ev_name] = fd
  [ev_name, fd]
end

#attach_raw_tracepoint(tp: "", fn_name: "") ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 324

def attach_raw_tracepoint(tp: "", fn_name: "")
  if @raw_tracepoint_fds.keys.include?(tp)
    raise "Raw tracepoint #{tp} has been attached"
  end

  fn = load_func(fn_name, BPF::RAW_TRACEPOINT)
  fd = Clib.bpf_attach_raw_tracepoint(fn[:fd], tp)
  if fd < 0
    raise SystemCallError.new("Failed to attach BPF program #{fn_name} to raw tracepoint #{tp}", Fiddle.last_error)
  end
  Util.debug "Attach: #{tp}"
  @raw_tracepoint_fds[tp] = fd
  self
end

#attach_tracepoint(tp: "", tp_re: "", fn_name: "") ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 312

def attach_tracepoint(tp: "", tp_re: "", fn_name: "")
  fn = load_func(fn_name, BPF::TRACEPOINT)
  tp_category, tp_name = tp.split(':')
  fd = Clib.bpf_attach_tracepoint(fn[:fd], tp_category, tp_name)
  if fd < 0
    raise SystemCallError.new("Failed to attach BPF program #{fn_name} to tracepoint #{tp}", Fiddle.last_error)
  end
  Util.debug "Attach: #{tp}"
  @tracepoint_fds[tp] = fd
  self
end

#attach_uprobe(name: "", sym: "", addr: nil, fn_name: "", pid: -1)) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 364

def attach_uprobe(name: "", sym: "", addr: nil, fn_name: "", pid: -1)
  path, addr = BCC.check_path_symbol(name, sym, addr, pid)

  fn = load_func(fn_name, BPF::KPROBE)
  ev_name = to_uprobe_evname("p", path, addr, pid)
  fd = Clib.bpf_attach_uprobe(fn[:fd], 0, ev_name, path, addr, pid)
  if fd < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  Util.debug "Attach: #{ev_name}"

  @uprobe_fds[ev_name] = fd
  [ev_name, fd]
end

#attach_uretprobe(name: "", sym: "", addr: nil, fn_name: "", pid: -1)) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 379

def attach_uretprobe(name: "", sym: "", addr: nil, fn_name: "", pid: -1)
  path, addr = BCC.check_path_symbol(name, sym, addr, pid)

  fn = load_func(fn_name, BPF::KPROBE)
  ev_name = to_uprobe_evname("r", path, addr, pid)
  fd = Clib.bpf_attach_uprobe(fn[:fd], 1, ev_name, path, addr, pid)
  if fd < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  Util.debug "Attach: #{ev_name}"

  @uprobe_fds[ev_name] = fd
  [ev_name, fd]
end

#cleanup ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 499

def cleanup
  @kprobe_fds.each do |k, v|
    detach_kprobe_event(k)
  end

  @uprobe_fds.each do |k, v|
    detach_uprobe_event(k)
  end

  @tracepoint_fds.each do |k, v|
    detach_tracepoint(k)
  end

  @raw_tracepoint_fds.each do |k, v|
    detach_raw_tracepoint(k)
  end

  if @module
    Clib.bpf_module_destroy(@module)
  end
end

#detach_kprobe_event(ev_name) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 422

def detach_kprobe_event(ev_name)
  unless @kprobe_fds.keys.include?(ev_name)
    raise "Event #{ev_name} not registered"
  end
  if Clib.bpf_close_perf_event_fd(@kprobe_fds[ev_name]) < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  if Clib.bpf_detach_kprobe(ev_name) < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  @kprobe_fds.delete(ev_name)
end

#detach_raw_tracepoint(tp) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 410

def detach_raw_tracepoint(tp)
  unless @raw_tracepoint_fds.keys.include?(tp)
    raise "Raw tracepoint #{tp} is not attached"
  end
  begin
    File.for_fd(@raw_tracepoint_fds[tp]).close
  rescue => e
    warn "Closing fd failed: #{e.inspect}. Ignore and skip"
  end
  @tracepoint_fds.delete(tp)
end

#detach_tracepoint(tp) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 394

def detach_tracepoint(tp)
  unless @tracepoint_fds.keys.include?(tp)
    raise "Tracepoint #{tp} is not attached"
  end
  res = Clib.bpf_close_perf_event_fd(@tracepoint_fds[tp])
  if res < 0
    raise "Failed to detach BPF from tracepoint"
  end
  tp_category, tp_name = tp.split(':')
  res = Clib.bpf_detach_tracepoint(tp_category, tp_name)
  if res < 0
    raise "Failed to detach BPF from tracepoint"
  end
  @tracepoint_fds.delete(tp)
end

#detach_uprobe_event(ev_name) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 435

def detach_uprobe_event(ev_name)
  unless @uprobe_fds.keys.include?(ev_name)
    raise "Event #{ev_name} not registered"
  end
  if Clib.bpf_close_perf_event_fd(@uprobe_fds[ev_name]) < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  if Clib.bpf_detach_uprobe(ev_name) < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  @uprobe_fds.delete(ev_name)
end

#gen_args_from_usdt ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 282

def gen_args_from_usdt
  ptr = Clib.bcc_usdt_genargs(@usdt_contexts.map(&:context).pack('J*'), @usdt_contexts.size)
  code = ""
  if !ptr || ptr.null?
    return nil
  end

  Clib.__extract_char ptr
end

#get_syscall_fnname(name) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 570

def get_syscall_fnname(name)
  get_syscall_prefix + name
end

#get_syscall_prefix ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 561

def get_syscall_prefix
  SYSCALL_PREFIXES.each do |prefix|
    if ksymname("%sbpf" % prefix)
      return prefix
    end
  end
  SYSCALL_PREFIXES[0]
end

#get_table(name, keytype: nil, leaftype: nil, reducer: nil) ⇒ Object

Raises:

  • (KeyError) 


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# File 'lib/rbbcc/bcc.rb', line 522

def get_table(name, keytype: nil, leaftype: nil, reducer: nil)
  map_id = Clib.bpf_table_id(@module, name)
  map_fd = Clib.bpf_table_fd(@module, name)

  raise KeyError, "map not found" if map_fd < 0
  unless keytype
    key_desc = Clib.bpf_table_key_desc(@module, name)
    raise("Failed to load BPF Table #{name} key desc") if key_desc.null?
    keytype = BCC.decode_table_type(eval(key_desc.to_extracted_char_ptr))
  end

  unless leaftype
    leaf_desc = Clib.bpf_table_leaf_desc(@module, name)
    raise("Failed to load BPF Table #{name} leaf desc") if leaf_desc.null?

    leaftype = BCC.decode_table_type(eval(leaf_desc.to_extracted_char_ptr))
  end
  return Table.new(self, map_id, map_fd, keytype, leaftype, name, reducer: reducer)
end

#ksymname(name) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 557

def ksymname(name)
  SymbolCache.resolve_global(name)
end

#load_func(func_name, prog_type, device: nil) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 292

def load_func(func_name, prog_type, device: nil)
  if @funcs.keys.include?(func_name)
    return @funcs[func_name]
  end

  log_level = 0
  fd = Clib.do_bcc_func_load(@module, prog_type, func_name,
         Clib.bpf_function_start(@module, func_name),
         Clib.bpf_function_size(@module, func_name),
         Clib.bpf_module_license(@module),
         Clib.bpf_module_kern_version(@module),
         log_level, nil, 0, device);
  if fd < 0
    raise SystemCallError.new(Fiddle.last_error)
  end
  fnobj = {fd: fd, name: func_name}
  @funcs[func_name] = fnobj
  return fnobj
end

#num_open_kprobes ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 448

def num_open_kprobes
  @kprobe_fds.size
end

#num_open_tracepoints ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 456

def num_open_tracepoints
  @tracepoint_fds.size
end

#num_open_uprobes ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 452

def num_open_uprobes
  @uprobe_fds.size
end

#perf_buffer_poll(timeout = -1)) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 550

def perf_buffer_poll(timeout=-1)
  readers = self.perf_buffers.values
  readers.each {|r| r.size = Clib::PerfReader.size }
  pack = readers.map{|r| r[0, Clib::PerfReader.size] }.pack('p*')
  Clib.perf_reader_poll(readers.size, pack, timeout)
end

#trace_fields(&do_each_line) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 480

def trace_fields(&do_each_line)
  ret = []
  while buf = trace_readline
    next if buf.start_with? "CPU:"
    task = buf[0..15].lstrip()
    meta, _addr, msg = buf[17..-1].split(": ", 3)
    pid, cpu, flags, ts = meta.split(" ")
    cpu = cpu[1..-2]

    if do_each_line
      do_each_line.call(task, pid, cpu, flags, ts, msg)
    else
      ret = [task, pid, cpu, flags, ts, msg]
      break
    end
  end
  ret
end

#trace_print(fmt: nil) ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 468

def trace_print(fmt: nil)
  loop do
    if fmt
    # TBD
    else
      line = trace_readline
    end
    puts line
    $stdout.flush
  end
end

#trace_readline ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 464

def trace_readline
  tracefile.readline(1024)
end

#tracefile ⇒ Object 



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# File 'lib/rbbcc/bcc.rb', line 460

def tracefile
  @tracefile ||= File.open("#{TRACEFS}/trace_pipe", "rb")
end