xref: /openbmc/qemu/scripts/qemu-trace-stap (revision efee71c8) 
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
21import argparse
22import copy
23import os.path
24import re
25import subprocess
26import sys
27
28
29def probe_prefix(binary):
30    dirname, filename = os.path.split(binary)
31    return re.sub("-", ".", filename) + ".log"
32
33
34def 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
43def 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
58def cmd_run(args):
59    prefix = probe_prefix(args.binary)
60    tapsets = tapset_dir(args.binary)
61
62    if args.verbose:
63        print("Using tapset dir '%s' for binary '%s'" % (tapsets, args.binary))
64
65    probes = []
66    for probe in args.probes:
67        probes.append("probe %s.%s {}" % (prefix, probe))
68    if len(probes) == 0:
69        print("At least one probe pattern must be specified")
70        sys.exit(1)
71
72    script = " ".join(probes)
73    if args.verbose:
74        print("Compiling script '%s'" % script)
75        script = """probe begin { print("Running script, <Ctrl>-c to quit\\n") } """ + script
76
77    # We request an 8MB buffer, since the stap default 1MB buffer
78    # can be easily overflowed by frequently firing QEMU traces
79    stapargs = ["stap", "-s", "8", "-I", tapsets ]
80    if args.pid is not None:
81        stapargs.extend(["-x", args.pid])
82    stapargs.extend(["-e", script])
83    subprocess.call(stapargs)
84
85
86def cmd_list(args):
87    tapsets = tapset_dir(args.binary)
88
89    if args.verbose:
90        print("Using tapset dir '%s' for binary '%s'" % (tapsets, args.binary))
91
92    def print_probes(verbose, name):
93        prefix = probe_prefix(args.binary)
94        offset = len(prefix) + 1
95        script = prefix + "." + name
96
97        if verbose:
98            print("Listing probes with name '%s'" % script)
99        proc = subprocess.Popen(["stap", "-I", tapsets, "-l", script],
100                                stdout=subprocess.PIPE,
101                                universal_newlines=True)
102        out, err = proc.communicate()
103        if proc.returncode != 0:
104            print("No probes found, are the tapsets installed in %s" % tapset_dir(args.binary))
105            sys.exit(1)
106
107        for line in out.splitlines():
108            if line.startswith(prefix):
109                print("%s" % line[offset:])
110
111    if len(args.probes) == 0:
112        print_probes(args.verbose, "*")
113    else:
114        for probe in args.probes:
115            print_probes(args.verbose, probe)
116
117
118def main():
119    parser = argparse.ArgumentParser(description="QEMU SystemTap trace tool")
120    parser.add_argument("-v", "--verbose", help="Print verbose progress info",
121                        action='store_true')
122
123    subparser = parser.add_subparsers(help="commands")
124    subparser.required = True
125    subparser.dest = "command"
126
127    runparser = subparser.add_parser("run", help="Run a trace session",
128                                     formatter_class=argparse.RawDescriptionHelpFormatter,
129                                     epilog="""
130
131To watch all trace points on the qemu-system-x86_64 binary:
132
133   %(argv0)s run qemu-system-x86_64
134
135To only watch the trace points matching the qio* and qcrypto* patterns
136
137   %(argv0)s run qemu-system-x86_64 'qio*' 'qcrypto*'
138""" % {"argv0": sys.argv[0]})
139    runparser.set_defaults(func=cmd_run)
140    runparser.add_argument("--pid", "-p", dest="pid",
141                           help="Restrict tracing to a specific process ID")
142    runparser.add_argument("binary", help="QEMU system or user emulator binary")
143    runparser.add_argument("probes", help="Probe names or wildcards",
144                           nargs=argparse.REMAINDER)
145
146    listparser = subparser.add_parser("list", help="List probe points",
147                                      formatter_class=argparse.RawDescriptionHelpFormatter,
148                                      epilog="""
149
150To list all trace points on the qemu-system-x86_64 binary:
151
152   %(argv0)s list qemu-system-x86_64
153
154To only list the trace points matching the qio* and qcrypto* patterns
155
156   %(argv0)s list qemu-system-x86_64 'qio*' 'qcrypto*'
157""" % {"argv0": sys.argv[0]})
158    listparser.set_defaults(func=cmd_list)
159    listparser.add_argument("binary", help="QEMU system or user emulator binary")
160    listparser.add_argument("probes", help="Probe names or wildcards",
161                            nargs=argparse.REMAINDER)
162
163    args = parser.parse_args()
164
165    args.func(args)
166    sys.exit(0)
167
168if __name__ == '__main__':
169    main()
170