PR5045: clean up after interrupts

2008-02-28  Frank Ch. Eigler  <fche@elastic.org>

	PR5045
	* session.h (pending_interrupts): New global.
	* main.cxx (handle_interrupts): New fn to handle SIGINT* etc.
	* elaborate.cxx, translate.cxx, tapsets.cxx, main.cxx (*): Insert
	pending_interrupts escape hatches inside potentially timetaking loops.
	* buildrun.cxx: Don't deal with signals.

7 files changed, 82 insertions, 16 deletions

diff --git a/ChangeLog b/ChangeLog
index 8be45cfc..ecfe4269 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2008-02-28  Frank Ch. Eigler  <fche@elastic.org>
+
+	PR5045
+	* session.h (pending_interrupts): New global.
+	* main.cxx (handle_interrupts): New fn to handle SIGINT* etc.
+	* elaborate.cxx, translate.cxx, tapsets.cxx, main.cxx (*): Insert
+	pending_interrupts escape hatches inside potentially timetaking loops.
+	* buildrun.cxx: Don't deal with signals.
+
 2008-02-27  Frank Ch. Eigler  <fche@elastic.org>
 
 	PR5697
diff --git a/buildrun.cxx b/buildrun.cxx
index 67836108..f3f29d49 100644
--- a/buildrun.cxx
+++ b/buildrun.cxx
@@ -16,7 +16,7 @@
 #include <sstream>
 
 extern "C" {
-#include "signal.h"
+#include <signal.h>
 #include <sys/wait.h>
 #include <pwd.h>
 #include <sys/types.h>
@@ -269,9 +269,6 @@ run_pass (systemtap_session& s)
   
   if (s.verbose>1) clog << "Running " << staprun_cmd << endl;
   
-  signal (SIGHUP, SIG_IGN);
-  signal (SIGINT, SIG_IGN);
   rc = system (staprun_cmd.c_str ());
-
   return rc;
 }
diff --git a/elaborate.cxx b/elaborate.cxx
index 7f4ccf35..75714102 100644
--- a/elaborate.cxx
+++ b/elaborate.cxx
@@ -344,6 +344,8 @@ match_node::find_and_build (systemtap_session& s,
 	  const match_key& subkey = i->first;
 	  match_node* subnode = i->second;
 
+          if (pending_interrupts) break;
+
 	  if (match.globmatch(subkey))
 	    {
 	      if (s.verbose > 2)
@@ -627,6 +629,8 @@ derive_probes (systemtap_session& s,
 {
   for (unsigned i = 0; i < p->locations.size(); ++i)
     {
+      if (pending_interrupts) break;
+
       probe_point *loc = p->locations[i];
 
       try
@@ -1070,6 +1074,7 @@ semantic_pass_symbols (systemtap_session& s)
   s.files.push_back (s.user_file);
   for (unsigned i = 0; i < s.files.size(); i++)
     {
+      if (pending_interrupts) break;
       stapfile* dome = s.files[i];
 
       // Pass 1: add globals and functions to systemtap-session master list,
@@ -1088,6 +1093,7 @@ semantic_pass_symbols (systemtap_session& s)
 
       for (unsigned i=0; i<dome->functions.size(); i++)
         {
+          if (pending_interrupts) break;
           functiondecl* fd = dome->functions[i];
 
           try 
@@ -1107,6 +1113,7 @@ semantic_pass_symbols (systemtap_session& s)
 
       for (unsigned i=0; i<dome->probes.size(); i++)
         {
+          if (pending_interrupts) break;
           probe* p = dome->probes [i];
           vector<derived_probe*> dps;
 
@@ -1116,6 +1123,7 @@ semantic_pass_symbols (systemtap_session& s)
 
           for (unsigned j=0; j<dps.size(); j++)
             {
+              if (pending_interrupts) break;
               derived_probe* dp = dps[j];
               s.probes.push_back (dp);
               dp->join_group (s);
@@ -2025,6 +2033,8 @@ semantic_pass_optimize1 (systemtap_session& s)
   bool relaxed_p = false;
   while (! relaxed_p)
     {
+      if (pending_interrupts) break;
+
       relaxed_p = true; // until proven otherwise
 
       semantic_pass_opt1 (s, relaxed_p);
@@ -2052,6 +2062,7 @@ semantic_pass_optimize2 (systemtap_session& s)
   bool relaxed_p = false;
   while (! relaxed_p)
     {
+      if (pending_interrupts) break;
       relaxed_p = true; // until proven otherwise
 
       semantic_pass_opt5 (s, relaxed_p);
@@ -2082,12 +2093,16 @@ semantic_pass_types (systemtap_session& s)
   // XXX: maybe convert to exception-based error signalling
   while (1)
     {
+      if (pending_interrupts) break;
+
       iterations ++;
       ti.num_newly_resolved = 0;
       ti.num_still_unresolved = 0;
 
       for (unsigned j=0; j<s.functions.size(); j++)
         {
+          if (pending_interrupts) break;
+
           functiondecl* fn = s.functions[j];
           ti.current_probe = 0;
           ti.current_function = fn;
@@ -2103,6 +2118,8 @@ semantic_pass_types (systemtap_session& s)
 
       for (unsigned j=0; j<s.probes.size(); j++)
         {
+          if (pending_interrupts) break;
+
           derived_probe* pn = s.probes[j];
           ti.current_function = 0;
           ti.current_probe = pn;
diff --git a/main.cxx b/main.cxx
index 668c14b8..449c1a2a 100644
--- a/main.cxx
+++ b/main.cxx
@@ -29,6 +29,7 @@
 extern "C" {
 #include <glob.h>
 #include <unistd.h>
+#include <signal.h>
 #include <sys/utsname.h>
 #include <sys/times.h>
 #include <sys/time.h>
@@ -185,6 +186,23 @@ printscript(systemtap_session& s, ostream& o)
     }
 }
 
+
+int pending_interrupts;
+
+extern "C"
+void handle_interrupt (int /* sig */) 
+{
+  pending_interrupts ++;
+  if (pending_interrupts > 1) // XXX: should be configurable? time-based?
+    {
+      char msg[] = "Too many interrupts received, exiting.\n";
+      int rc = write (2, msg, sizeof(msg)-1);
+      if (rc) /* Do nothing; we don't care if our last gasp went out. */ ;
+      _exit (1);
+    }
+}
+
+
 int
 main (int argc, char * const argv [])
 {
@@ -541,6 +559,13 @@ main (int argc, char * const argv [])
   // directory.
   s.translated_source = string(s.tmpdir) + "/" + s.module_name + ".c";
 
+  // Set up our handler to catch routine signals, to allow clean 
+  // and reasonably timely exit.
+  signal (SIGHUP, handle_interrupt);
+  signal (SIGPIPE, handle_interrupt);
+  signal (SIGINT, handle_interrupt);
+  signal (SIGTERM, handle_interrupt);
+
   struct tms tms_before;
   times (& tms_before);
   struct timeval tv_before;
@@ -616,8 +641,10 @@ main (int argc, char * const argv [])
 
           for (unsigned j=0; j<globbuf.gl_pathc; j++)
             {
-              // privilege only for /usr/share/systemtap?
-              
+              if (pending_interrupts)
+                break;
+
+              // XXX: privilege only for /usr/share/systemtap?
               stapfile* f = parser::parse (s, globbuf.gl_pathv[j], true);
               if (f == 0)
                 rc ++;
@@ -683,7 +710,7 @@ main (int argc, char * const argv [])
          << "Try again with more '-v' (verbose) options."
          << endl;
 
-  if (rc || s.last_pass == 1) goto cleanup;
+  if (rc || s.last_pass == 1 || pending_interrupts) goto cleanup;
 
   times (& tms_before);
   gettimeofday (&tv_before, NULL);
@@ -733,14 +760,14 @@ main (int argc, char * const argv [])
         {
 	  // If our last pass isn't 5, we're done (since passes 3 and
 	  // 4 just generate what we just pulled out of the cache).
-	  if (s.last_pass < 5) goto cleanup;
+	  if (s.last_pass < 5 || pending_interrupts) goto cleanup;
 
 	  // Short-circuit to pass 5.
 	  goto pass_5;
 	}
     }
 
-  if (rc || s.last_pass == 2) goto cleanup;
+  if (rc || s.last_pass == 2 || pending_interrupts) goto cleanup;
 
   // PASS 3: TRANSLATION
 
@@ -769,7 +796,7 @@ main (int argc, char * const argv [])
          << "Try again with more '-v' (verbose) options."
          << endl;
 
-  if (rc || s.last_pass == 3) goto cleanup;
+  if (rc || s.last_pass == 3 || pending_interrupts) goto cleanup;
 
   // PASS 4: COMPILATION
   times (& tms_before);
@@ -799,7 +826,7 @@ main (int argc, char * const argv [])
 	add_to_cache(s);
 
       // Copy module to the current directory.
-      if (save_module)
+      if (save_module && !pending_interrupts)
         {
 	  string module_src_path = s.tmpdir + "/" + s.module_name + ".ko";
 	  string module_dest_path = s.module_name + ".ko";
@@ -813,7 +840,7 @@ main (int argc, char * const argv [])
 	}
     }
 
-  if (rc || s.last_pass == 4) goto cleanup;
+  if (rc || s.last_pass == 4 || pending_interrupts) goto cleanup;
 
 
   // PASS 5: RUN
@@ -841,7 +868,7 @@ pass_5:
  cleanup:
 
   // update the database information
-  if (!rc && s.tapset_compile_coverage) {
+  if (!rc && s.tapset_compile_coverage && !pending_interrupts) {
 #ifdef HAVE_LIBSQLITE3
     update_coverage_db(s);
 #else
@@ -867,5 +894,5 @@ pass_5:
         }
     }
 
-  return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+  return (rc||pending_interrupts) ? EXIT_FAILURE : EXIT_SUCCESS;
 }
diff --git a/session.h b/session.h
index e2d7cd4f..b06d9ecc 100644
--- a/session.h
+++ b/session.h
@@ -160,4 +160,7 @@ struct systemtap_session
 };
 
 
+// global counter of SIGINT/SIGTERM's received
+extern int pending_interrupts;
+
 #endif // SESSION_H
diff --git a/tapsets.cxx b/tapsets.cxx
index c5ed6ea1..52c14024 100644
--- a/tapsets.cxx
+++ b/tapsets.cxx
@@ -827,6 +827,7 @@ struct dwflpp
         ptrdiff_t off = 0;
         do
           {
+            if (pending_interrupts) return;
             off = dwfl_getmodules (dwfl, module_caching_callback,
                                    & module_cache, off);
           }
@@ -837,6 +838,7 @@ struct dwflpp
     // Traverse the cache.
     for (unsigned i = 0; i < module_cache.size(); i++)
       {
+        if (pending_interrupts) return;
         module_cache_entry& it = module_cache[i];
         int rc = callback (it.mod, 0, it.name, it.addr, data);
         if (rc != DWARF_CB_OK) break;
@@ -868,6 +870,7 @@ struct dwflpp
         Dwarf_Off noff;
         while (dwarf_nextcu (dw, off, &noff, &cuhl, NULL, NULL, NULL) == 0)
           {
+            if (pending_interrupts) return;
             Dwarf_Die die_mem;
             Dwarf_Die *die;
             die = dwarf_offdie (dw, off + cuhl, &die_mem);
@@ -878,6 +881,7 @@ struct dwflpp
 
     for (unsigned i = 0; i < v->size(); i++)
       {
+        if (pending_interrupts) return;
         Dwarf_Die die = v->at(i);
         int rc = (*callback)(& die, data);
         if (rc != DWARF_CB_OK) break;
@@ -1057,6 +1061,7 @@ struct dwflpp
       {
 	for (size_t i = 0; i < nsrcs; ++i)
 	  {
+            if (pending_interrupts) return;
             if (srcsp [i]) // skip over mismatched lines
               callback (srcsp[i], data);
 	  }
@@ -3012,6 +3017,7 @@ static int
 query_cu (Dwarf_Die * cudie, void * arg)
 {
   dwarf_query * q = static_cast<dwarf_query *>(arg);
+  if (pending_interrupts) return DWARF_CB_ABORT;
 
   try
     {
diff --git a/translate.cxx b/translate.cxx
index fefb0c8f..855a8e93 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -4471,18 +4471,21 @@ translate_pass (systemtap_session& s)
       s.op->newline(1);
       for (unsigned i=0; i<s.globals.size(); i++)
         {
+          if (pending_interrupts) return 1;
           s.up->emit_global_init (s.globals[i]);
         }
       s.op->newline(-1) << "};";
 
       for (unsigned i=0; i<s.functions.size(); i++)
 	{
+          if (pending_interrupts) return 1;
 	  s.op->newline();
 	  s.up->emit_functionsig (s.functions[i]);
 	}
 
       for (unsigned i=0; i<s.functions.size(); i++)
 	{
+          if (pending_interrupts) return 1;
 	  s.op->newline();
 	  s.up->emit_function (s.functions[i]);
 	}
@@ -4492,12 +4495,16 @@ translate_pass (systemtap_session& s)
       // emit_locks()/emit_unlocks().
       for (unsigned i=0; i<s.probes.size(); i++)
 	{
-	  if (s.probes[i]->needs_global_locks())
+        if (pending_interrupts) return 1;
+        if (s.probes[i]->needs_global_locks())
 	    s.probes[i]->body->visit (&cup.vcv_needs_global_locks);
 	}
 
       for (unsigned i=0; i<s.probes.size(); i++)
-        s.up->emit_probe (s.probes[i]);
+        {
+          if (pending_interrupts) return 1;
+          s.up->emit_probe (s.probes[i]);
+        }
 
       s.op->newline();
       s.up->emit_module_init ();