Separate the kernel.mark tapset

1 files changed, 712 insertions, 0 deletions

diff --git a/tapset-mark.cxx b/tapset-mark.cxx
new file mode 100644
index 00000000..1f0ef2ce
--- /dev/null
+++ b/tapset-mark.cxx
@@ -0,0 +1,712 @@
+// tapset for kernel static markers
+// Copyright (C) 2005-2009 Red Hat Inc.
+// Copyright (C) 2005-2007 Intel Corporation.
+// Copyright (C) 2008 James.Bottomley@HansenPartnership.com
+//
+// This file is part of systemtap, and is free software.  You can
+// redistribute it and/or modify it under the terms of the GNU General
+// Public License (GPL); either version 2, or (at your option) any
+// later version.
+
+#include "session.h"
+#include "tapsets.h"
+#include "translate.h"
+#include "util.h"
+
+#include <cerrno>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+
+extern "C" {
+#include <fnmatch.h>
+}
+
+
+using namespace std;
+using namespace __gnu_cxx;
+
+
+static string TOK_KERNEL("kernel");
+static string TOK_MARK("mark");
+static string TOK_FORMAT("format");
+
+
+// ------------------------------------------------------------------------
+// statically inserted macro-based derived probes
+// ------------------------------------------------------------------------
+
+struct mark_arg
+{
+  bool str;
+  string c_type;
+  exp_type stp_type;
+};
+
+struct mark_derived_probe: public derived_probe
+{
+  mark_derived_probe (systemtap_session &s,
+                      const string& probe_name, const string& probe_format,
+                      probe* base_probe, probe_point* location);
+
+  systemtap_session& sess;
+  string probe_name, probe_format;
+  vector <struct mark_arg *> mark_args;
+  bool target_symbol_seen;
+
+  void join_group (systemtap_session& s);
+  void print_dupe_stamp (ostream& o);
+  void emit_probe_context_vars (translator_output* o);
+  void initialize_probe_context_vars (translator_output* o);
+  void printargs (std::ostream &o) const;
+
+  void parse_probe_format ();
+};
+
+
+struct mark_derived_probe_group: public generic_dpg<mark_derived_probe>
+{
+public:
+  void emit_module_decls (systemtap_session& s);
+  void emit_module_init (systemtap_session& s);
+  void emit_module_exit (systemtap_session& s);
+};
+
+
+struct mark_var_expanding_visitor: public var_expanding_visitor
+{
+  mark_var_expanding_visitor(systemtap_session& s, const string& pn,
+                             vector <struct mark_arg *> &mark_args):
+    sess (s), probe_name (pn), mark_args (mark_args),
+    target_symbol_seen (false) {}
+  systemtap_session& sess;
+  string probe_name;
+  vector <struct mark_arg *> &mark_args;
+  bool target_symbol_seen;
+
+  void visit_target_symbol (target_symbol* e);
+  void visit_target_symbol_arg (target_symbol* e);
+  void visit_target_symbol_context (target_symbol* e);
+};
+
+
+void
+mark_var_expanding_visitor::visit_target_symbol_arg (target_symbol* e)
+{
+  string argnum_s = e->base_name.substr(4,e->base_name.length()-4);
+  int argnum = atoi (argnum_s.c_str());
+
+  if (argnum < 1 || argnum > (int)mark_args.size())
+    throw semantic_error ("invalid marker argument number", e->tok);
+
+  if (is_active_lvalue (e))
+    throw semantic_error("write to marker parameter not permitted", e->tok);
+
+  if (e->components.size() > 0)
+    {
+      switch (e->components[0].first)
+	{
+	case target_symbol::comp_literal_array_index:
+	  throw semantic_error("marker argument may not be used as array",
+			       e->tok);
+	  break;
+	case target_symbol::comp_struct_member:
+	  throw semantic_error("marker argument may not be used as a structure",
+			       e->tok);
+	  break;
+	default:
+	  throw semantic_error ("invalid marker argument use", e->tok);
+	  break;
+	}
+    }
+
+  // Remember that we've seen a target variable.
+  target_symbol_seen = true;
+
+  e->probe_context_var = "__mark_arg" + lex_cast<string>(argnum);
+  e->type = mark_args[argnum-1]->stp_type;
+  provide (e);
+}
+
+
+void
+mark_var_expanding_visitor::visit_target_symbol_context (target_symbol* e)
+{
+  string sname = e->base_name;
+
+  if (is_active_lvalue (e))
+    throw semantic_error("write to marker '" + sname + "' not permitted", e->tok);
+
+  if (e->components.size() > 0)
+    {
+      switch (e->components[0].first)
+	{
+	case target_symbol::comp_literal_array_index:
+	  throw semantic_error("marker '" + sname + "' may not be used as array",
+			       e->tok);
+	  break;
+	case target_symbol::comp_struct_member:
+	  throw semantic_error("marker '" + sname + "' may not be used as a structure",
+			       e->tok);
+	  break;
+	default:
+	  throw semantic_error ("invalid marker '" + sname + "' use", e->tok);
+	  break;
+	}
+    }
+
+  string fname;
+  if (e->base_name == "$format") {
+    fname = string("_mark_format_get");
+  } else {
+    fname = string("_mark_name_get");
+  }
+
+  // Synthesize a functioncall.
+  functioncall* n = new functioncall;
+  n->tok = e->tok;
+  n->function = fname;
+  n->referent = 0; // NB: must not resolve yet, to ensure inclusion in session
+  provide (n);
+}
+
+void
+mark_var_expanding_visitor::visit_target_symbol (target_symbol* e)
+{
+  assert(e->base_name.size() > 0 && e->base_name[0] == '$');
+
+  if (e->base_name.substr(0,4) == "$arg")
+    visit_target_symbol_arg (e);
+  else if (e->base_name == "$format" || e->base_name == "$name")
+    visit_target_symbol_context (e);
+  else
+    throw semantic_error ("invalid target symbol for marker, $argN, $name or $format expected",
+			  e->tok);
+}
+
+
+
+mark_derived_probe::mark_derived_probe (systemtap_session &s,
+                                        const string& p_n,
+                                        const string& p_f,
+                                        probe* base, probe_point* loc):
+  derived_probe (base, new probe_point(*loc) /* .components soon rewritten */),
+  sess (s), probe_name (p_n), probe_format (p_f),
+  target_symbol_seen (false)
+{
+  // create synthetic probe point name; preserve condition
+  vector<probe_point::component*> comps;
+  comps.push_back (new probe_point::component (TOK_KERNEL));
+  comps.push_back (new probe_point::component (TOK_MARK, new literal_string (probe_name)));
+  comps.push_back (new probe_point::component (TOK_FORMAT, new literal_string (probe_format)));
+  this->sole_location()->components = comps;
+
+  // expand the marker format
+  parse_probe_format();
+
+  // Now expand the local variables in the probe body
+  mark_var_expanding_visitor v (sess, name, mark_args);
+  this->body = v.require (this->body);
+  target_symbol_seen = v.target_symbol_seen;
+
+  if (sess.verbose > 2)
+    clog << "marker-based " << name << " mark=" << probe_name
+	 << " fmt='" << probe_format << "'" << endl;
+}
+
+
+static int
+skip_atoi(const char **s)
+{
+  int i = 0;
+  while (isdigit(**s))
+    i = i * 10 + *((*s)++) - '0';
+  return i;
+}
+
+
+void
+mark_derived_probe::parse_probe_format()
+{
+  const char *fmt = probe_format.c_str();
+  int qualifier;		// 'h', 'l', or 'L' for integer fields
+  mark_arg *arg;
+
+  for (; *fmt ; ++fmt)
+    {
+      if (*fmt != '%')
+        {
+	  /* Skip text */
+	  continue;
+	}
+
+repeat:
+      ++fmt;
+
+      // skip conversion flags (if present)
+      switch (*fmt)
+        {
+	case '-':
+	case '+':
+	case ' ':
+	case '#':
+	case '0':
+	  goto repeat;
+	}
+
+      // skip minimum field witdh (if present)
+      if (isdigit(*fmt))
+	skip_atoi(&fmt);
+
+      // skip precision (if present)
+      if (*fmt == '.')
+        {
+	  ++fmt;
+	  if (isdigit(*fmt))
+	    skip_atoi(&fmt);
+	}
+
+      // get the conversion qualifier (if present)
+      qualifier = -1;
+      if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L')
+        {
+	  qualifier = *fmt;
+	  ++fmt;
+	  if (qualifier == 'l' && *fmt == 'l')
+	    {
+	      qualifier = 'L';
+	      ++fmt;
+	    }
+	}
+
+      // get the conversion type
+      switch (*fmt)
+        {
+	case 'c':
+	  arg = new mark_arg;
+	  arg->str = false;
+	  arg->c_type = "int";
+	  arg->stp_type = pe_long;
+	  mark_args.push_back(arg);
+	  continue;
+
+	case 's':
+	  arg = new mark_arg;
+	  arg->str = true;
+	  arg->c_type = "char *";
+	  arg->stp_type = pe_string;
+	  mark_args.push_back(arg);
+	  continue;
+
+	case 'p':
+	  arg = new mark_arg;
+	  arg->str = false;
+	  // This should really be 'void *'.  But, then we'll get a
+	  // compile error when we assign the void pointer to an
+	  // integer without a cast.  So, we use 'long' instead, since
+	  // it should have the same size as 'void *'.
+	  arg->c_type = "long";
+	  arg->stp_type = pe_long;
+	  mark_args.push_back(arg);
+	  continue;
+
+	case '%':
+	  continue;
+
+	case 'o':
+	case 'X':
+	case 'x':
+	case 'd':
+	case 'i':
+	case 'u':
+	  // fall through...
+	  break;
+
+	default:
+	  if (!*fmt)
+	    --fmt;
+	  continue;
+	}
+
+      arg = new mark_arg;
+      arg->str = false;
+      arg->stp_type = pe_long;
+      switch (qualifier)
+        {
+	case 'L':
+	  arg->c_type = "long long";
+	  break;
+
+	case 'l':
+	  arg->c_type = "long";
+	  break;
+
+	case 'h':
+	  arg->c_type = "short";
+	  break;
+
+	default:
+	  arg->c_type = "int";
+	  break;
+	}
+      mark_args.push_back(arg);
+    }
+}
+
+
+void
+mark_derived_probe::join_group (systemtap_session& s)
+{
+  if (! s.mark_derived_probes)
+    {
+      s.mark_derived_probes = new mark_derived_probe_group ();
+
+      // Make sure <linux/marker.h> is included early.
+      embeddedcode *ec = new embeddedcode;
+      ec->tok = NULL;
+      ec->code = string("#if ! defined(CONFIG_MARKERS)\n")
+	+ string("#error \"Need CONFIG_MARKERS!\"\n")
+	+ string("#endif\n")
+	+ string("#include <linux/marker.h>\n");
+
+      s.embeds.push_back(ec);
+    }
+  s.mark_derived_probes->enroll (this);
+}
+
+
+void
+mark_derived_probe::print_dupe_stamp (ostream& o)
+{
+  if (target_symbol_seen)
+    for (unsigned i = 0; i < mark_args.size(); i++)
+      o << mark_args[i]->c_type << " __mark_arg" << (i+1) << endl;
+}
+
+
+void
+mark_derived_probe::emit_probe_context_vars (translator_output* o)
+{
+  // If we haven't seen a target symbol for this probe, quit.
+  if (! target_symbol_seen)
+    return;
+
+  for (unsigned i = 0; i < mark_args.size(); i++)
+    {
+      string localname = "__mark_arg" + lex_cast<string>(i+1);
+      switch (mark_args[i]->stp_type)
+        {
+	case pe_long:
+	  o->newline() << "int64_t " << localname << ";";
+	  break;
+	case pe_string:
+	  o->newline() << "string_t " << localname << ";";
+	  break;
+	default:
+	  throw semantic_error ("cannot expand unknown type");
+	  break;
+	}
+    }
+}
+
+
+void
+mark_derived_probe::initialize_probe_context_vars (translator_output* o)
+{
+  // If we haven't seen a target symbol for this probe, quit.
+  if (! target_symbol_seen)
+    return;
+
+  bool deref_fault_needed = false;
+  for (unsigned i = 0; i < mark_args.size(); i++)
+    {
+      string localname = "l->__mark_arg" + lex_cast<string>(i+1);
+      switch (mark_args[i]->stp_type)
+        {
+	case pe_long:
+	  o->newline() << localname << " = va_arg(*c->mark_va_list, "
+		       << mark_args[i]->c_type << ");";
+	  break;
+
+	case pe_string:
+	  // We're assuming that this is a kernel string (this code is
+	  // basically the guts of kernel_string), not a user string.
+	  o->newline() << "{ " << mark_args[i]->c_type
+		       << " tmp_str = va_arg(*c->mark_va_list, "
+		       << mark_args[i]->c_type << ");";
+	  o->newline() << "deref_string (" << localname
+		       << ", tmp_str, MAXSTRINGLEN); }";
+	  deref_fault_needed = true;
+	  break;
+
+	default:
+	  throw semantic_error ("cannot expand unknown type");
+	  break;
+	}
+    }
+  if (deref_fault_needed)
+    // Need to report errors?
+    o->newline() << "deref_fault: ;";
+}
+
+void
+mark_derived_probe::printargs(std::ostream &o) const
+{
+  for (unsigned i = 0; i < mark_args.size(); i++)
+    {
+      string localname = "$arg" + lex_cast<string>(i+1);
+      switch (mark_args[i]->stp_type)
+        {
+        case pe_long:
+          o << " " << localname << ":long";
+          break;
+        case pe_string:
+          o << " " << localname << ":string";
+          break;
+        default:
+          o << " " << localname << ":unknown";
+          break;
+        }
+    }
+}
+
+
+void
+mark_derived_probe_group::emit_module_decls (systemtap_session& s)
+{
+  if (probes.empty())
+    return;
+
+  s.op->newline() << "/* ---- marker probes ---- */";
+
+  s.op->newline() << "static struct stap_marker_probe {";
+  s.op->newline(1) << "const char * const name;";
+  s.op->newline() << "const char * const format;";
+  s.op->newline() << "const char * const pp;";
+  s.op->newline() << "void (* const ph) (struct context *);";
+
+  s.op->newline(-1) << "} stap_marker_probes [" << probes.size() << "] = {";
+  s.op->indent(1);
+  for (unsigned i=0; i < probes.size(); i++)
+    {
+      s.op->newline () << "{";
+      s.op->line() << " .name=" << lex_cast_qstring(probes[i]->probe_name)
+		   << ",";
+      s.op->line() << " .format=" << lex_cast_qstring(probes[i]->probe_format)
+		   << ",";
+      s.op->line() << " .pp=" << lex_cast_qstring (*probes[i]->sole_location())
+		   << ",";
+      s.op->line() << " .ph=&" << probes[i]->name;
+      s.op->line() << " },";
+    }
+  s.op->newline(-1) << "};";
+  s.op->newline();
+
+
+  // Emit the marker callback function
+  s.op->newline();
+  s.op->newline() << "static void enter_marker_probe (void *probe_data, void *call_data, const char *fmt, va_list *args) {";
+  s.op->newline(1) << "struct stap_marker_probe *smp = (struct stap_marker_probe *)probe_data;";
+  common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", "smp->pp");
+  s.op->newline() << "c->marker_name = smp->name;";
+  s.op->newline() << "c->marker_format = smp->format;";
+  s.op->newline() << "c->mark_va_list = args;";
+  s.op->newline() << "(*smp->ph) (c);";
+  s.op->newline() << "c->mark_va_list = NULL;";
+  s.op->newline() << "c->data = NULL;";
+
+  common_probe_entryfn_epilogue (s.op);
+  s.op->newline(-1) << "}";
+
+  return;
+}
+
+
+void
+mark_derived_probe_group::emit_module_init (systemtap_session &s)
+{
+  if (probes.size () == 0)
+    return;
+
+  s.op->newline() << "/* init marker probes */";
+  s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {";
+  s.op->newline(1) << "struct stap_marker_probe *smp = &stap_marker_probes[i];";
+  s.op->newline() << "probe_point = smp->pp;";
+  s.op->newline() << "rc = marker_probe_register(smp->name, smp->format, enter_marker_probe, smp);";
+  s.op->newline() << "if (rc) {";
+  s.op->newline(1) << "for (j=i-1; j>=0; j--) {"; // partial rollback
+  s.op->newline(1) << "struct stap_marker_probe *smp2 = &stap_marker_probes[j];";
+  s.op->newline() << "marker_probe_unregister(smp2->name, enter_marker_probe, smp2);";
+  s.op->newline(-1) << "}";
+  s.op->newline() << "break;"; // don't attempt to register any more probes
+  s.op->newline(-1) << "}";
+  s.op->newline(-1) << "}"; // for loop
+}
+
+
+void
+mark_derived_probe_group::emit_module_exit (systemtap_session& s)
+{
+  if (probes.empty())
+    return;
+
+  s.op->newline() << "/* deregister marker probes */";
+  s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {";
+  s.op->newline(1) << "struct stap_marker_probe *smp = &stap_marker_probes[i];";
+  s.op->newline() << "marker_probe_unregister(smp->name, enter_marker_probe, smp);";
+  s.op->newline(-1) << "}"; // for loop
+}
+
+
+struct mark_builder: public derived_probe_builder
+{
+private:
+  bool cache_initialized;
+  typedef multimap<string, string> mark_cache_t;
+  typedef multimap<string, string>::const_iterator mark_cache_const_iterator_t;
+  typedef pair<mark_cache_const_iterator_t, mark_cache_const_iterator_t>
+    mark_cache_const_iterator_pair_t;
+  mark_cache_t mark_cache;
+
+public:
+  mark_builder(): cache_initialized(false) {}
+
+  void build_no_more (systemtap_session &s)
+  {
+    if (! mark_cache.empty())
+      {
+        if (s.verbose > 3)
+          clog << "mark_builder releasing cache" << endl;
+	mark_cache.clear();
+      }
+  }
+
+  void build(systemtap_session & sess,
+             probe * base,
+             probe_point * location,
+             literal_map_t const & parameters,
+             vector<derived_probe *> & finished_results);
+};
+
+
+void
+mark_builder::build(systemtap_session & sess,
+		    probe * base,
+		    probe_point *loc,
+		    literal_map_t const & parameters,
+		    vector<derived_probe *> & finished_results)
+{
+  string mark_str_val;
+  bool has_mark_str = get_param (parameters, TOK_MARK, mark_str_val);
+  string mark_format_val;
+  bool has_mark_format = get_param (parameters, TOK_FORMAT, mark_format_val);
+  assert (has_mark_str);
+  (void) has_mark_str;
+
+  if (! cache_initialized)
+    {
+      cache_initialized = true;
+      string module_markers_path = sess.kernel_build_tree + "/Module.markers";
+      
+      ifstream module_markers;
+      module_markers.open(module_markers_path.c_str(), ifstream::in);
+      if (! module_markers)
+        {
+	  if (sess.verbose>3)
+	    clog << module_markers_path << " cannot be opened: "
+		 << strerror(errno) << endl;
+	  return;
+	}
+
+      string name, module, format;
+      do
+        {
+	  module_markers >> name >> module;
+	  getline(module_markers, format);
+
+	  // trim leading whitespace
+	  string::size_type notwhite = format.find_first_not_of(" \t");
+	  format.erase(0, notwhite);
+
+	  // If the format is empty, make sure we add back a space
+	  // character, which is what MARK_NOARGS expands to.
+	  if (format.length() == 0)
+	    format = " ";
+
+	  if (sess.verbose>3)
+	    clog << "'" << name << "' '" << module << "' '" << format
+		 << "'" << endl;
+
+	  if (mark_cache.count(name) > 0)
+	    {
+	      // If we have 2 markers with the same we've got 2 cases:
+	      // different format strings or duplicate format strings.
+	      // If an existing marker in the cache doesn't have the
+	      // same format string, add this marker.
+	      mark_cache_const_iterator_pair_t ret;
+	      mark_cache_const_iterator_t it;
+	      bool matching_format_string = false;
+
+	      ret = mark_cache.equal_range(name);
+	      for (it = ret.first; it != ret.second; ++it)
+	        {
+		  if (format == it->second)
+		    {
+		      matching_format_string = true;
+		      break;
+		    }
+		}
+
+	      if (! matching_format_string)
+	        mark_cache.insert(pair<string,string>(name, format));
+	  }
+	  else
+	    mark_cache.insert(pair<string,string>(name, format));
+	}
+      while (! module_markers.eof());
+      module_markers.close();
+    }
+
+  // Search marker list for matching markers
+  for (mark_cache_const_iterator_t it = mark_cache.begin();
+       it != mark_cache.end(); it++)
+    {
+      // Below, "rc" has negative polarity: zero iff matching.
+      int rc = fnmatch(mark_str_val.c_str(), it->first.c_str(), 0);
+      if (! rc)
+        {
+	  bool add_result = true;
+
+	  // Match format strings (if the user specified one)
+	  if (has_mark_format && fnmatch(mark_format_val.c_str(),
+					 it->second.c_str(), 0))
+	    add_result = false;
+
+	  if (add_result)
+	    {
+	      derived_probe *dp
+		= new mark_derived_probe (sess,
+					  it->first, it->second,
+					  base, loc);
+	      finished_results.push_back (dp);
+	    }
+	}
+    }
+}
+
+
+
+void
+register_tapset_mark(systemtap_session& s)
+{
+  match_node* root = s.pattern_root;
+  derived_probe_builder *builder = new mark_builder();
+
+  root = root->bind(TOK_KERNEL);
+  root = root->bind_str(TOK_MARK);
+
+  root->bind(builder);
+  root->bind_str(TOK_FORMAT)->bind(builder);
+}
+
+/* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */