autoconf: standardize CPU_KHZ based on session kernel_exports

* buildrun.cxx (output_cpu_khz): Replace with generalized
  output_exportconf().

1 files changed, 11 insertions, 35 deletions

diff --git a/buildrun.cxx b/buildrun.cxx
index 0140c69f..89fa0177 100644
--- a/buildrun.cxx
+++ b/buildrun.cxx
@@ -90,43 +90,19 @@ output_autoconf(systemtap_session& s, ofstream& o, const char *autoconf_c,
   o << "; fi >> $@" << endl;
 }
 
-void output_cpu_khz (systemtap_session& s, ofstream& o)
+
+void output_exportconf(systemtap_session& s, ofstream& o, const char *symbol,
+                     const char *deftrue)
 {
-  // PR10493: search cpu_khz in Module.symvers
-  string kernel_export_file = s.kernel_build_tree + "/Module.symvers";
-  char *line = NULL, *name = NULL, *module = NULL, *type = NULL;
-  size_t len = 0;
-  unsigned long address;
-  int ret;
-  FILE *sym = fopen(kernel_export_file.c_str(),"r");
-  
-  if (sym == NULL)
-    return;
-  while (!feof(sym))
-    {
-      if (getline(&line, &len, sym) < 0)
-         break;
-      ret = sscanf(line, "%lx %as %as %as", &address, &name, &module, &type);
-      if (name == NULL || module == NULL || type == NULL) 
-         continue;
-      if (ret == 4) {
-         // cpu_khz is kernel EXPORT_SYMBOL'd
-         if (!strcmp(name, "cpu_khz") && !strcmp(module, "vmlinux")
-             && strstr(type, "EXPORT_SYMBOL")) // match all to avoid corrupt file
-          {
-            o << "\t";
-            if (s.verbose < 4)
-               o << "@";
-            o << "echo \"#define STAPCONF_CPU_KHZ 1\"";
-            o << ">> $@" << endl;
-            break;
-          }
-      }
-    }
-  if (sym)
-    fclose(sym);
+  o << "\t";
+  if (s.verbose < 4)
+    o << "@";
+  if (s.kernel_exports.find(symbol) != s.kernel_exports.end())
+    o << "echo \"#define " << deftrue << " 1\"";
+  o << ">> $@" << endl;
 }
 
+
 int
 compile_pass (systemtap_session& s)
 {
@@ -204,7 +180,7 @@ compile_pass (systemtap_session& s)
   output_autoconf(s, o, "autoconf-trace-printk.c", "STAPCONF_TRACE_PRINTK", NULL);
   output_autoconf(s, o, "autoconf-regset.c", "STAPCONF_REGSET", NULL);
   output_autoconf(s, o, "autoconf-utrace-regset.c", "STAPCONF_UTRACE_REGSET", NULL);
-  output_cpu_khz(s, o);
+  output_exportconf(s, o, "cpu_khz", "STAPCONF_CPU_KHZ");
 
 #if 0
   /* NB: For now, the performance hit of probe_kernel_read/write (vs. our