1 files changed, 129 insertions, 0 deletions
diff --git a/scripts/tracetool/format/log_stap.py b/scripts/tracetool/format/log_stap.py
new file mode 100644
index 0000000000..b49afababd
--- /dev/null
+++ b/scripts/tracetool/format/log_stap.py
@@ -0,0 +1,129 @@
+# -*- coding: utf-8 -*-
+
+"""
+Generate .stp file that printfs log messages (DTrace with SystemTAP only).
+"""
+
+__author__     = "Daniel P. Berrange <berrange@redhat.com>"
+__copyright__  = "Copyright (C) 2014-2019, Red Hat, Inc."
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Daniel Berrange"
+__email__      = "berrange@redhat.com"
+
+import re
+
+from tracetool import out
+from tracetool.backend.dtrace import binary, probeprefix
+from tracetool.backend.simple import is_string
+from tracetool.format.stap import stap_escape
+
+def global_var_name(name):
+    return probeprefix().replace(".", "_") + "_" + name
+
+STATE_SKIP = 0
+STATE_LITERAL = 1
+STATE_MACRO = 2
+
+def c_macro_to_format(macro):
+    if macro.startswith("PRI"):
+        return macro[3]
+
+    raise Exception("Unhandled macro '%s'" % macro)
+
+def c_fmt_to_stap(fmt):
+    state = 0
+    bits = []
+    literal = ""
+    macro = ""
+    escape = 0;
+    for i in range(len(fmt)):
+        if fmt[i] == '\\':
+            if escape:
+                escape = 0
+            else:
+                escape = 1
+            if state != STATE_LITERAL:
+                raise Exception("Unexpected escape outside string literal")
+            literal = literal + fmt[i]
+        elif fmt[i] == '"' and not escape:
+            if state == STATE_LITERAL:
+                state = STATE_SKIP
+                bits.append(literal)
+                literal = ""
+            else:
+                if state == STATE_MACRO:
+                    bits.append(c_macro_to_format(macro))
+                    macro = ""
+                state = STATE_LITERAL
+        elif fmt[i] == ' ' or fmt[i] == '\t':
+            if state == STATE_MACRO:
+                bits.append(c_macro_to_format(macro))
+                macro = ""
+                state = STATE_SKIP
+            elif state == STATE_LITERAL:
+                literal = literal + fmt[i]
+        else:
+            escape = 0
+            if state == STATE_SKIP:
+                state = STATE_MACRO
+
+            if state == STATE_LITERAL:
+                literal = literal + fmt[i]
+            else:
+                macro = macro + fmt[i]
+
+    if state == STATE_MACRO:
+        bits.append(c_macro_to_format(macro))
+    elif state == STATE_LITERAL:
+        bits.append(literal)
+
+    # All variables in systemtap are 64-bit in size
+    # The "%l" integer size qualifier is thus redundant
+    # and "%ll" is not valid at all. Similarly the size_t
+    # based "%z" size qualifier is not valid. We just
+    # strip all size qualifiers for sanity.
+    fmt = re.sub(r"%(\d*)(l+|z)(x|u|d)", r"%\1\3", "".join(bits))
+    return fmt
+
+def generate(events, backend, group):
+    out('/* This file is autogenerated by tracetool, do not edit. */',
+        '')
+
+    for event_id, e in enumerate(events):
+        if 'disable' in e.properties:
+            continue
+
+        out('probe %(probeprefix)s.log.%(name)s = %(probeprefix)s.%(name)s ?',
+            '{',
+            probeprefix=probeprefix(),
+            name=e.name)
+
+        # Get references to userspace strings
+        for type_, name in e.args:
+            name = stap_escape(name)
+            if is_string(type_):
+                out('    try {',
+                    '        arg%(name)s_str = %(name)s ? ' +
+                    'user_string_n(%(name)s, 512) : "<null>"',
+                    '    } catch {}',
+                    name=name)
+
+        # Determine systemtap's view of variable names
+        fields = ["pid()", "gettimeofday_ns()"]
+        for type_, name in e.args:
+            name = stap_escape(name)
+            if is_string(type_):
+                fields.append("arg" + name + "_str")
+            else:
+                fields.append(name)
+
+        # Emit the entire record in a single SystemTap printf()
+        arg_str = ', '.join(arg for arg in fields)
+        fmt_str = "%d@%d " + e.name + " " + c_fmt_to_stap(e.fmt) + "\\n"
+        out('    printf("%(fmt_str)s", %(arg_str)s)',
+            fmt_str=fmt_str, arg_str=arg_str)
+
+        out('}')
+
+    out()