scripts/qemu-trace-stap

   1 #!/usr/bin/env python3
   2 # -*- python -*-
   3 #
   4 # Copyright (C) 2019 Red Hat, Inc
   5 #
   6 # QEMU SystemTap Trace Tool
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program; if not, see <http://www.gnu.org/licenses/>.
  20
  21 import argparse
  22 import copy
  23 import os.path
  24 import re
  25 import subprocess
  26 import sys
  27
  28
  29 def probe_prefix(binary):
  30     dirname, filename = os.path.split(binary)
  31     return re.sub("-", ".", filename) + ".log"
  32
  33
  34 def which(binary):
  35     for path in os.environ["PATH"].split(os.pathsep):
  36         if os.path.exists(os.path.join(path, binary)):
  37                 return os.path.join(path, binary)
  38
  39     print("Unable to find '%s' in $PATH" % binary)
  40     sys.exit(1)
  41
  42
  43 def tapset_dir(binary):
  44     dirname, filename = os.path.split(binary)
  45     if dirname == '':
  46         thisfile = which(binary)
  47     else:
  48         thisfile = os.path.realpath(binary)
  49         if not os.path.exists(thisfile):
  50             print("Unable to find '%s'" % thisfile)
  51             sys.exit(1)
  52
  53     basedir = os.path.split(thisfile)[0]
  54     tapset = os.path.join(basedir, "..", "share", "systemtap", "tapset")
  55     return os.path.realpath(tapset)
  56
  57
  58 def tapset_env(tapset_dir):
  59     tenv = copy.copy(os.environ)
  60     tenv["SYSTEMTAP_TAPSET"] = tapset_dir
  61     return tenv
  62
  63 def cmd_run(args):
  64     prefix = probe_prefix(args.binary)
  65     tapsets = tapset_dir(args.binary)
  66
  67     if args.verbose:
  68         print("Using tapset dir '%s' for binary '%s'" % (tapsets, args.binary))
  69
  70     probes = []
  71     for probe in args.probes:
  72         probes.append("probe %s.%s {}" % (prefix, probe))
  73     if len(probes) == 0:
  74         print("At least one probe pattern must be specified")
  75         sys.exit(1)
  76
  77     script = " ".join(probes)
  78     if args.verbose:
  79         print("Compiling script '%s'" % script)
  80         script = """probe begin { print("Running script, <Ctrl>-c to quit\\n") } """ + script
  81
  82     # We request an 8MB buffer, since the stap default 1MB buffer
  83     # can be easily overflowed by frequently firing QEMU traces
  84     stapargs = ["stap", "-s", "8"]
  85     if args.pid is not None:
  86         stapargs.extend(["-x", args.pid])
  87     stapargs.extend(["-e", script])
  88     subprocess.call(stapargs, env=tapset_env(tapsets))
  89
  90
  91 def cmd_list(args):
  92     tapsets = tapset_dir(args.binary)
  93
  94     if args.verbose:
  95         print("Using tapset dir '%s' for binary '%s'" % (tapsets, args.binary))
  96
  97     def print_probes(verbose, name):
  98         prefix = probe_prefix(args.binary)
  99         offset = len(prefix) + 1
 100         script = prefix + "." + name
 101
 102         if verbose:
 103             print("Listing probes with name '%s'" % script)
 104         proc = subprocess.Popen(["stap", "-l", script],
 105                                 stdout=subprocess.PIPE,
 106                                 universal_newlines=True,
 107                                 env=tapset_env(tapsets))
 108         out, err = proc.communicate()
 109         if proc.returncode != 0:
 110             print("No probes found, are the tapsets installed in %s" % tapset_dir(args.binary))
 111             sys.exit(1)
 112
 113         for line in out.splitlines():
 114             if line.startswith(prefix):
 115                 print("%s" % line[offset:])
 116
 117     if len(args.probes) == 0:
 118         print_probes(args.verbose, "*")
 119     else:
 120         for probe in args.probes:
 121             print_probes(args.verbose, probe)
 122
 123
 124 def main():
 125     parser = argparse.ArgumentParser(description="QEMU SystemTap trace tool")
 126     parser.add_argument("-v", "--verbose", help="Print verbose progress info",
 127                         action='store_true')
 128
 129     subparser = parser.add_subparsers(help="commands")
 130     subparser.required = True
 131     subparser.dest = "command"
 132
 133     runparser = subparser.add_parser("run", help="Run a trace session",
 134                                      formatter_class=argparse.RawDescriptionHelpFormatter,
 135                                      epilog="""
 136
 137 To watch all trace points on the qemu-system-x86_64 binary:
 138
 139    %(argv0)s run qemu-system-x86_64
 140
 141 To only watch the trace points matching the qio* and qcrypto* patterns
 142
 143    %(argv0)s run qemu-system-x86_64 'qio*' 'qcrypto*'
 144 """ % {"argv0": sys.argv[0]})
 145     runparser.set_defaults(func=cmd_run)
 146     runparser.add_argument("--pid", "-p", dest="pid",
 147                            help="Restrict tracing to a specific process ID")
 148     runparser.add_argument("binary", help="QEMU system or user emulator binary")
 149     runparser.add_argument("probes", help="Probe names or wildcards",
 150                            nargs=argparse.REMAINDER)
 151
 152     listparser = subparser.add_parser("list", help="List probe points",
 153                                       formatter_class=argparse.RawDescriptionHelpFormatter,
 154                                       epilog="""
 155
 156 To list all trace points on the qemu-system-x86_64 binary:
 157
 158    %(argv0)s list qemu-system-x86_64
 159
 160 To only list the trace points matching the qio* and qcrypto* patterns
 161
 162    %(argv0)s list qemu-system-x86_64 'qio*' 'qcrypto*'
 163 """ % {"argv0": sys.argv[0]})
 164     listparser.set_defaults(func=cmd_list)
 165     listparser.add_argument("binary", help="QEMU system or user emulator binary")
 166     listparser.add_argument("probes", help="Probe names or wildcards",
 167                             nargs=argparse.REMAINDER)
 168
 169     args = parser.parse_args()
 170
 171     args.func(args)
 172     sys.exit(0)
 173
 174 if __name__ == '__main__':
 175     main()