2005-09-28 Frank Ch. Eigler <fche@elastic.org>

	PR 1182.
	* main.cxx (main): Support -D macro-setting option.
	* stap.1.in: Document it and related macros.
	* buildrun.cxx (compile_pass): Emit macro definitions.
	* translate.cxx (translate_pass): Guard limit macros with #ifdef.
	Eliminate MAXCONCURRENCY macro.
	* elaborate.h (systemtap_session): Add "macros" field.
	* parse.cxx (parse_if_statement): Clear "elseblock" if needed.

2005-09-28  Frank Ch. Eigler  <fche@elastic.org>

	PR 1182.
	* systemtap.samples/control_limits.*: New test.

7 files changed, 84 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 8e8d1e7d..16bd913a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2005-09-28  Frank Ch. Eigler  <fche@elastic.org>
+
+	PR 1182.
+	* main.cxx (main): Support -D macro-setting option.
+	* stap.1.in: Document it and related macros.
+	* buildrun.cxx (compile_pass): Emit macro definitions.
+	* translate.cxx (translate_pass): Guard limit macros with #ifdef.
+	Eliminate MAXCONCURRENCY macro.
+	* elaborate.h (systemtap_session): Add "macros" field.
+	* parse.cxx (parse_if_statement): Clear "elseblock" if needed.
+
 2005-09-27  Frank Ch. Eigler  <fche@elastic.org>
 
 	* tapsets.cxx (query_cu_containing_global_address): Tolerate
diff --git a/buildrun.cxx b/buildrun.cxx
index 130f4a1b..598d7110 100644
--- a/buildrun.cxx
+++ b/buildrun.cxx
@@ -20,6 +20,26 @@ extern "C" {
 using namespace std;
 
 
+// return as quoted string, with at least '"' backslash-escaped
+template <typename IN> inline string
+lex_cast_qstring(IN const & in)
+{
+  stringstream ss;
+  string out, out2;
+  if (!(ss << in))
+    throw runtime_error("bad lexical cast");
+  out = ss.str();
+  out2 += '"';
+  for (unsigned i=0; i<out.length(); i++)
+    {
+      if (out[i] == '"') // XXX others?
+	out2 += '\\';
+      out2 += out[i];
+    }
+  out2 += '"';
+  return out2;
+}
+
 
 int
 compile_pass (systemtap_session& s)
@@ -30,10 +50,15 @@ compile_pass (systemtap_session& s)
   int rc = 0;
 
   // Create makefile
+
+  for (unsigned i=0; i<s.macros.size(); i++)
+    o << "CFLAGS += -D " << lex_cast_qstring(s.macros[i]) << endl;
+
   if (s.test_mode)
     {
       string module_dir = string("/lib/modules/")
         + s.kernel_release + "/build";
+
       o << "CFLAGS += -I \"" << module_dir << "/include\"" << endl;
       o << "CFLAGS += -I \"" << s.runtime_path << "/user\"" << endl;
       o << "CFLAGS += -I \"" << s.runtime_path << "\"" << endl;
@@ -41,7 +66,6 @@ compile_pass (systemtap_session& s)
       o << s.module_name << ": " << s.translated_source << endl;
       o << "\t$(CC) $(CFLAGS) -o " << s.module_name
         << " " << s.translated_source << endl;
-      o.close ();
     }
   else
     {
@@ -50,9 +74,10 @@ compile_pass (systemtap_session& s)
       o << "CFLAGS += -I \"" << s.runtime_path << "\"" << endl;
       o << "CFLAGS += -I \"" << s.runtime_path << "/relayfs\"" << endl;
       o << "obj-m := " << s.module_name << ".o" << endl;
-      o.close ();
     }
 
+  o.close ();
+
   // Run make
   if (s.test_mode)
     {
diff --git a/elaborate.h b/elaborate.h
index 6482952c..22fea82f 100644
--- a/elaborate.h
+++ b/elaborate.h
@@ -202,6 +202,7 @@ struct systemtap_session
 
   // command line args
   std::vector<std::string> include_path;
+  std::vector<std::string> macros;
   std::vector<std::string> args;
   std::string kernel_release;
   std::string runtime_path;
diff --git a/main.cxx b/main.cxx
index dcdf67f5..860e18b0 100644
--- a/main.cxx
+++ b/main.cxx
@@ -71,6 +71,7 @@ usage (systemtap_session& s)
   for (unsigned i=0; i<s.include_path.size(); i++)
     clog << "              " << s.include_path[i] << endl;
   clog
+    << "   -D NM=VAL  emit macro definition into generated C code" << endl
     << "   -R DIR     look in DIR for runtime, instead of" << endl
     <<      "              " << s.runtime_path << endl
     // << "   -r RELEASE use kernel RELEASE, instead of" << endl
@@ -135,7 +136,7 @@ main (int argc, char * const argv [])
 
   while (true)
     {
-      int grc = getopt (argc, argv, "hVvp:I:e:o:tR:r:m:kgc:x:");
+      int grc = getopt (argc, argv, "hVvp:I:e:o:tR:r:m:kgc:x:D:");
       if (grc < 0)
         break;
       switch (grc)
@@ -204,6 +205,10 @@ main (int argc, char * const argv [])
 	  s.target_pid = atoi(optarg);
 	  break;
 
+	case 'D':
+	  s.macros.push_back (string (optarg));
+	  break;
+
         case 'h':
         default:
           usage (s);
diff --git a/parse.cxx b/parse.cxx
index a1a54011..9f714359 100644
--- a/parse.cxx
+++ b/parse.cxx
@@ -946,6 +946,8 @@ parser::parse_if_statement ()
       next ();
       s->elseblock = parse_statement ();
     }
+  else
+    s->elseblock = 0; // in case not otherwise initialized
 
   return s;
 }
diff --git a/stap.1.in b/stap.1.in
index 0a0fb33d..b6922108 100644
--- a/stap.1.in
+++ b/stap.1.in
@@ -100,6 +100,10 @@ section for details.
 Add the given directory to the tapset search directory.  See the
 description of pass 2 for details.
 .TP
+.BI \-D " NAME=VALUE"
+Add the given preprocessor directive to the module Makefile.  These can 
+be used to override limit parameters described below.
+.TP
 .BI \-R " DIR"
 Look for the systemtap runtime sources in the given directory.
 .TP
@@ -471,7 +475,6 @@ See the
 .IR stapex (5)
 manual page for a collection of samples.
 
-
 .SH SAFETY AND SECURITY
 Systemtap is an administrative tool.  It exposes kernel internal data
 structures and potentially private user information.  It acquires root
@@ -497,6 +500,28 @@ against manipulation by concurrent probe handlers.  Use of guru mode
 constructs such as embedded C can violate these constraints, leading
 to kernel crash or data corruption.
 .PP
+The resource use limits are set by macros in the generated C code.
+These may be overridden with the
+.R -D
+flag.  A selection of these is as follows: 
+.TP
+MAXNESTING
+Maximum number of recursive function call levels.
+.TP
+MAXSTRINGLEN
+Maximum length of strings.
+.TP
+MAXTRYLOCK
+Maximum number of iterations to wait for locks on global variables
+before declaring possible deadlock.
+.TP
+MAXACTION
+Maximum number of statements to execute during any single probe hit.
+.TP
+MAXMAPENTRIES
+Maximum number of rows in any single global array.
+
+.PP
 In case something goes wrong with 
 .IR stap " or " stpd
 after a probe has already started running, one may safely kill both
diff --git a/translate.cxx b/translate.cxx
index cc4b58c5..a7caf0bd 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -670,7 +670,7 @@ c_unparser::emit_common_header ()
       o->newline(-1) << "} function_" << c_varname (fd->name) << ";";
     }
   o->newline(-1) << "} locals [MAXNESTING];";
-  o->newline(-1) << "} contexts [MAXCONCURRENCY];" << endl;
+  o->newline(-1) << "} contexts [NR_CPUS];" << endl;
 
   emit_map_type_instantiations ();
 }
@@ -2376,12 +2376,21 @@ translate_pass (systemtap_session& s)
       // This is at the very top of the file.
       s.op->line() << "#define TEST_MODE " << (s.test_mode ? 1 : 0) << endl;
 
+      s.op->newline() << "#ifndef MAXNESTING";
       s.op->newline() << "#define MAXNESTING 30";
-      s.op->newline() << "#define MAXCONCURRENCY NR_CPUS";
+      s.op->newline() << "#endif";
+      s.op->newline() << "#ifndef MAXSTRINGLEN";
       s.op->newline() << "#define MAXSTRINGLEN 128";
+      s.op->newline() << "#endif";
+      s.op->newline() << "#ifndef MAXTRYLOCK";
       s.op->newline() << "#define MAXTRYLOCK 20";
+      s.op->newline() << "#endif";
+      s.op->newline() << "#ifndef MAXACTION";
       s.op->newline() << "#define MAXACTION 1000";
+      s.op->newline() << "#endif";
+      s.op->newline() << "#ifndef MAXMAPENTRIES";
       s.op->newline() << "#define MAXMAPENTRIES 2048";
+      s.op->newline() << "#endif";
 
       // impedance mismatch
       s.op->newline() << "#define STP_STRING_SIZE MAXSTRINGLEN";