Merge pull request #530 from iovisor/bblanco_dev

Add check for number of arguments

src/cc/frontends/clang/b_frontend_action.cc

@@ -32,6 +32,7 @@
 
 namespace ebpf {
 
+constexpr int MAX_CALLING_CONV_REGS = 6;
 const char *calling_conv_regs_x86[] = {
   "di", "si", "dx", "cx", "r8", "r9"
 };
@@ -255,6 +256,11 @@ bool BTypeVisitor::VisitFunctionDecl(FunctionDecl *D) {
   if (D->isExternallyVisible() && D->hasBody()) {
     string attr = string("__attribute__((section(\"") + BPF_FN_PREFIX + D->getName().str() + "\")))\n";
     rewriter_.InsertText(D->getLocStart(), attr);
+    if (D->param_size() > MAX_CALLING_CONV_REGS + 1) {
+      error(D->getParamDecl(MAX_CALLING_CONV_REGS + 1)->getLocStart(),
+            "too many arguments, bcc only supports in-register parameters");
+      return false;
+    }
     // remember the arg names of the current function...first one is the ctx
     fn_args_.clear();
     string preamble = "{";
@@ -265,12 +271,24 @@ bool BTypeVisitor::VisitFunctionDecl(FunctionDecl *D) {
       }
       fn_args_.push_back(arg);
       if (fn_args_.size() > 1) {
+        // Move the args into a preamble section where the same params are
+        // declared and initialized from pt_regs.
+        // Todo: this init should be done only when the program requests it.
+        string text = rewriter_.getRewrittenText(
+            SourceRange(arg->getLocStart(), arg->getLocEnd()));
         arg->addAttr(UnavailableAttr::CreateImplicit(C, "ptregs"));
         size_t d = fn_args_.size() - 2;
         const char *reg = calling_conv_regs[d];
-        preamble += arg->getName().str() + " = " + fn_args_[0]->getName().str() + "->" + string(reg) + ";";
+        preamble += " " + text + " = " + fn_args_[0]->getName().str() + "->" +
+                    string(reg) + ";";
       }
     }
+    if (D->param_size() > 1) {
+      rewriter_.ReplaceText(
+          SourceRange(D->getParamDecl(0)->getLocEnd(),
+                      D->getParamDecl(D->getNumParams() - 1)->getLocEnd()),
+          fn_args_[0]->getName());
+    }
     // for each trace argument, convert the variable from ptregs to something on stack
     if (CompoundStmt *S = dyn_cast<CompoundStmt>(D->getBody()))
       rewriter_.ReplaceText(S->getLBracLoc(), 1, preamble);

src/python/bcc/__init__.py

@@ -446,7 +446,7 @@ class BPF(object):
 
     @staticmethod
     def find_library(libname):
-        return lib.bcc_procutils_which_so(libname)
+        return lib.bcc_procutils_which_so(libname.encode("ascii")).decode()
 
     def attach_uprobe(self, name="", sym="", addr=None,
             fn_name="", pid=-1, cpu=0, group_fd=-1):

tests/python/test_clang.py

@@ -328,5 +328,15 @@ BPF_TABLE("hash", struct bpf_tunnel_key, int, t1, 1);
         t1 = b["t1"]
         print(t1.Key().remote_ipv4)
 
+    def test_too_many_args(self):
+        text = """
+#include <uapi/linux/ptrace.h>
+int many(struct pt_regs *ctx, int a, int b, int c, int d, int e, int f, int g) {
+    return 0;
+}
+"""
+        with self.assertRaises(Exception):
+            b = BPF(text=text)
+
 if __name__ == "__main__":
     main()

tests/python/test_stackid.py

@@ -47,7 +47,7 @@ int kprobe__htab_map_lookup_elem(struct pt_regs *ctx, struct bpf_map *map, u64 *
         stackid = stack_entries[k]
         self.assertIsNotNone(stackid)
         stack = stack_traces[stackid].ip
-        self.assertEqual(b.ksym(stack[0]), b"htab_map_lookup_elem")
+        self.assertEqual(b.ksym(stack[0]), "htab_map_lookup_elem")
 
 
 if __name__ == "__main__":

tools/argdist.py

@@ -673,8 +673,8 @@ struct __string_t { char s[%d]; };
                 except:
                         if self.args.verbose:
                                 traceback.print_exc()
-                        elif sys.exc_type is not SystemExit:
-                                print(sys.exc_value)
+                        elif sys.exc_info()[0] is not SystemExit:
+                                print(sys.exc_info()[1])
                 self._close_probes()
 
 if __name__ == "__main__":

tools/tplist.py

@@ -86,6 +86,6 @@ if __name__ == "__main__":
                 else:
                         print_tracepoints()
         except:
-                if sys.exc_type is not SystemExit:
-                        print(sys.exc_value)
+                if sys.exc_info()[0] is not SystemExit:
+                        print(sys.exc_info()[1])