text: #!/usr/bin/python
  # @lint-avoid-python-3-compatibility-imports
  #
  # opensnoop Trace open() syscalls.
  #           For Linux, uses BCC, eBPF. Embedded C.
  #
  # USAGE: opensnoop [-h] [-T] [-x] [-p PID] [-d DURATION] [-t TID] [-n NAME]
  #
  # Copyright (c) 2015 Brendan Gregg.
  # Licensed under the Apache License, Version 2.0 (the "License")
  #
  # 17-Sep-2015   Brendan Gregg   Created this.
  # 29-Apr-2016   Allan McAleavy  Updated for BPF_PERF_OUTPUT.
  # 08-Oct-2016   Dina Goldshtein Support filtering by PID and TID.
  # 28-Dec-2018   Tim Douglas     Print flags argument, enable filtering
  # 06-Jan-2019   Takuma Kume     Support filtering by UID
  
  from __future__ import print_function
  from bcc import ArgString, BPF
  from bcc.utils import printb
  import argparse
  from datetime import datetime, timedelta
  import os
  
  # arguments
  examples = """examples:
      ./opensnoop           # trace all open() syscalls
      ./opensnoop -T        # include timestamps
      ./opensnoop -U        # include UID
      ./opensnoop -x        # only show failed opens
      ./opensnoop -p 181    # only trace PID 181
      ./opensnoop -t 123    # only trace TID 123
      ./opensnoop -u 1000   # only trace UID 1000
      ./opensnoop -d 10     # trace for 10 seconds only
      ./opensnoop -n main   # only print process names containing "main"
      ./opensnoop -e        # show extended fields
      ./opensnoop -f O_WRONLY -f O_RDWR  # only print calls for writing
      ./opensnoop --cgroupmap ./mappath  # only trace cgroups in this BPF map
  """
  parser = argparse.ArgumentParser(
      description="Trace open() syscalls",
      formatter_class=argparse.RawDescriptionHelpFormatter,
      epilog=examples)
  parser.add_argument("-T", "--timestamp", action="store_true",
      help="include timestamp on output")
  parser.add_argument("-U", "--print-uid", action="store_true",
      help="print UID column")
  parser.add_argument("-x", "--failed", action="store_true",
      help="only show failed opens")
  parser.add_argument("-p", "--pid",
      help="trace this PID only")
  parser.add_argument("-t", "--tid",
      help="trace this TID only")
  parser.add_argument("--cgroupmap",
      help="trace cgroups in this BPF map only")
  parser.add_argument("-u", "--uid",
      help="trace this UID only")
  parser.add_argument("-d", "--duration",
      help="total duration of trace in seconds")
  parser.add_argument("-n", "--name",
      type=ArgString,
      help="only print process names containing this name")
  parser.add_argument("--ebpf", action="store_true",
      help=argparse.SUPPRESS)
  parser.add_argument("-e", "--extended_fields", action="store_true",
      help="show extended fields")
  parser.add_argument("-f", "--flag_filter", action="append",
      help="filter on flags argument (e.g., O_WRONLY)")
  args = parser.parse_args()
  debug = 0
  if args.duration:
      args.duration = timedelta(seconds=int(args.duration))
  flag_filter_mask = 0
  for flag in args.flag_filter or []:
      if not flag.startswith('O_'):
          exit("Bad flag: %s" % flag)
      try:
          flag_filter_mask |= getattr(os, flag)
      except AttributeError:
          exit("Bad flag: %s" % flag)
  
  # define BPF program
  bpf_text = """
  #include <uapi/linux/ptrace.h>
  #include <uapi/linux/limits.h>
  #include <linux/sched.h>
  
  struct val_t {
      u64 id;
      char comm[TASK_COMM_LEN];
      const char *fname;
      int flags; // EXTENDED_STRUCT_MEMBER
  };
  
  struct data_t {
      u64 id;
      u64 ts;
      u32 uid;
      int ret;
      char comm[TASK_COMM_LEN];
      char fname[NAME_MAX];
      int flags; // EXTENDED_STRUCT_MEMBER
  };
  
  #if CGROUPSET
  BPF_TABLE_PINNED("hash", u64, u64, cgroupset, 1024, "CGROUPPATH");
  #endif
  BPF_PERF_OUTPUT(events);
  """
  
  bpf_text_kprobe = """
  BPF_HASH(infotmp, u64, struct val_t);
  
  int trace_entry(struct pt_regs *ctx, int dfd, const char __user *filename, int flags)
  {
      struct val_t val = {};
      u64 id = bpf_get_current_pid_tgid();
      u32 pid = id >> 32; // PID is higher part
      u32 tid = id;       // Cast and get the lower part
      u32 uid = bpf_get_current_uid_gid();
  
      PID_TID_FILTER
      UID_FILTER
      FLAGS_FILTER
  #if CGROUPSET
      u64 cgroupid = bpf_get_current_cgroup_id();
      if (cgroupset.lookup(&cgroupid) == NULL) {
        return 0;
      }
  #endif
      if (bpf_get_current_comm(&val.comm, sizeof(val.comm)) == 0) {
          val.id = id;
          val.fname = filename;
          val.flags = flags; // EXTENDED_STRUCT_MEMBER
          infotmp.update(&id, &val);
      }
  
      return 0;
  };
  
  int trace_return(struct pt_regs *ctx)
  {
      u64 id = bpf_get_current_pid_tgid();
      struct val_t *valp;
      struct data_t data = {};
  
      u64 tsp = bpf_ktime_get_ns();
  
      valp = infotmp.lookup(&id);
      if (valp == 0) {
          // missed entry
          return 0;
      }
      bpf_probe_read(&data.comm, sizeof(data.comm), valp->comm);
      bpf_probe_read_user(&data.fname, sizeof(data.fname), (void *)valp->fname);
      data.id = valp->id;
      data.ts = tsp / 1000;
      data.uid = bpf_get_current_uid_gid();
      data.flags = valp->flags; // EXTENDED_STRUCT_MEMBER
      data.ret = PT_REGS_RC(ctx);
  
      events.perf_submit(ctx, &data, sizeof(data));
      infotmp.delete(&id);
  
      return 0;
  }
  """
  
  bpf_text_kfunc= """
  KRETFUNC_PROBE(do_sys_open, int dfd, const char __user *filename, int flags, int mode, int ret)
  {
      u64 id = bpf_get_current_pid_tgid();
      u32 pid = id >> 32; // PID is higher part
      u32 tid = id;       // Cast and get the lower part
      u32 uid = bpf_get_current_uid_gid();
  
      PID_TID_FILTER
      UID_FILTER
      FLAGS_FILTER
  #if CGROUPSET
      u64 cgroupid = bpf_get_current_cgroup_id();
      if (cgroupset.lookup(&cgroupid) == NULL) {
        return 0;
      }
  #endif
  
      struct data_t data = {};
      bpf_get_current_comm(&data.comm, sizeof(data.comm));
  
      u64 tsp = bpf_ktime_get_ns();
  
      bpf_probe_read_user(&data.fname, sizeof(data.fname), (void *)filename);
      data.id    = id;
      data.ts    = tsp / 1000;
      data.uid   = bpf_get_current_uid_gid();
      data.flags = flags; // EXTENDED_STRUCT_MEMBER
      data.ret   = ret;
  
      events.perf_submit(ctx, &data, sizeof(data));
  }
  """
  
  is_support_kfunc = BPF.support_kfunc()
  if is_support_kfunc:
      bpf_text += bpf_text_kfunc
  else:
      bpf_text += bpf_text_kprobe
  
  if args.tid:  # TID trumps PID
      bpf_text = bpf_text.replace('PID_TID_FILTER',
          'if (tid != %s) { return 0; }' % args.tid)
  elif args.pid:
      bpf_text = bpf_text.replace('PID_TID_FILTER',
          'if (pid != %s) { return 0; }' % args.pid)
  else:
      bpf_text = bpf_text.replace('PID_TID_FILTER', '')
  if args.uid:
      bpf_text = bpf_text.replace('UID_FILTER',
          'if (uid != %s) { return 0; }' % args.uid)
  else:
      bpf_text = bpf_text.replace('UID_FILTER', '')
  if args.cgroupmap:
      bpf_text = bpf_text.replace('CGROUPSET', '1')
      bpf_text = bpf_text.replace('CGROUPPATH', args.cgroupmap)
  else:
      bpf_text = bpf_text.replace('CGROUPSET', '0')
  if args.flag_filter:
      bpf_text = bpf_text.replace('FLAGS_FILTER',
          'if (!(flags & %d)) { return 0; }' % flag_filter_mask)
  else:
      bpf_text = bpf_text.replace('FLAGS_FILTER', '')
  if not (args.extended_fields or args.flag_filter):
      bpf_text = '\n'.join(x for x in bpf_text.split('\n')
          if 'EXTENDED_STRUCT_MEMBER' not in x)
  if debug or args.ebpf:
      print(bpf_text)
      if args.ebpf:
          exit()
  
  # initialize BPF
  b = BPF(text=bpf_text)
  if not is_support_kfunc:
      b.attach_kprobe(event="do_sys_open", fn_name="trace_entry")
      b.attach_kretprobe(event="do_sys_open", fn_name="trace_return")
  
  initial_ts = 0
  
  # header
  if args.timestamp:
      print("%-14s" % ("TIME(s)"), end="")
  if args.print_uid:
      print("%-6s" % ("UID"), end="")
  print("%-6s %-16s %4s %3s " %
        ("TID" if args.tid else "PID", "COMM", "FD", "ERR"), end="")
  if args.extended_fields:
      print("%-9s" % ("FLAGS"), end="")
  print("PATH")
  
  # process event
  def print_event(cpu, data, size):
      event = b["events"].event(data)
      global initial_ts
  
      # split return value into FD and errno columns
      if event.ret >= 0:
          fd_s = event.ret
          err = 0
      else:
          fd_s = -1
          err = - event.ret
  
      if not initial_ts:
          initial_ts = event.ts
  
      if args.failed and (event.ret >= 0):
          return
  
      if args.name and bytes(args.name) not in event.comm:
          return
  
      if args.timestamp:
          delta = event.ts - initial_ts
          printb(b"%-14.9f" % (float(delta) / 1000000), nl="")
  
      if args.print_uid:
          printb(b"%-6d" % event.uid, nl="")
  
      printb(b"%-6d %-16s %4d %3d " %
             (event.id & 0xffffffff if args.tid else event.id >> 32,
              event.comm, fd_s, err), nl="")
  
      if args.extended_fields:
          printb(b"%08o " % event.flags, nl="")
  
      printb(b'%s' % event.fname)
  
  # loop with callback to print_event
  b["events"].open_perf_buffer(print_event, page_cnt=64)
  start_time = datetime.now()
  while not args.duration or datetime.now() - start_time < args.duration:
      try:
          b.perf_buffer_poll()
      except KeyboardInterrupt:
          exit()
  