| /* |
| * Copyright (c) 2015 PLUMgrid, Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| #include <linux/bpf.h> |
| #include <linux/version.h> |
| #include <sys/utsname.h> |
| #include <unistd.h> |
| #include <stdlib.h> |
| |
| #include <clang/AST/ASTConsumer.h> |
| #include <clang/AST/ASTContext.h> |
| #include <clang/AST/RecordLayout.h> |
| #include <clang/Frontend/CompilerInstance.h> |
| #include <clang/Frontend/MultiplexConsumer.h> |
| #include <clang/Rewrite/Core/Rewriter.h> |
| |
| #include "b_frontend_action.h" |
| #include "bpf_module.h" |
| #include "common.h" |
| #include "loader.h" |
| #include "table_storage.h" |
| #include "arch_helper.h" |
| |
| #include "libbpf.h" |
| |
| namespace ebpf { |
| |
| constexpr int MAX_CALLING_CONV_REGS = 6; |
| const char *calling_conv_regs_x86[] = { |
| "di", "si", "dx", "cx", "r8", "r9" |
| }; |
| const char *calling_conv_regs_ppc[] = {"gpr[3]", "gpr[4]", "gpr[5]", |
| "gpr[6]", "gpr[7]", "gpr[8]"}; |
| |
| const char *calling_conv_regs_s390x[] = {"gprs[2]", "gprs[3]", "gprs[4]", |
| "gprs[5]", "gprs[6]" }; |
| |
| const char *calling_conv_regs_arm64[] = {"regs[0]", "regs[1]", "regs[2]", |
| "regs[3]", "regs[4]", "regs[5]"}; |
| |
| void *get_call_conv_cb(bcc_arch_t arch) |
| { |
| const char **ret; |
| |
| switch(arch) { |
| case BCC_ARCH_PPC: |
| case BCC_ARCH_PPC_LE: |
| ret = calling_conv_regs_ppc; |
| break; |
| case BCC_ARCH_S390X: |
| ret = calling_conv_regs_s390x; |
| break; |
| case BCC_ARCH_ARM64: |
| ret = calling_conv_regs_arm64; |
| break; |
| default: |
| ret = calling_conv_regs_x86; |
| } |
| |
| return (void *)ret; |
| } |
| |
| const char **get_call_conv(void) { |
| const char **ret; |
| |
| ret = (const char **)run_arch_callback(get_call_conv_cb); |
| return ret; |
| } |
| |
| using std::map; |
| using std::move; |
| using std::set; |
| using std::string; |
| using std::to_string; |
| using std::unique_ptr; |
| using std::vector; |
| using namespace clang; |
| |
| class ProbeChecker : public RecursiveASTVisitor<ProbeChecker> { |
| public: |
| explicit ProbeChecker(Expr *arg, const set<Decl *> &ptregs) |
| : needs_probe_(false), is_transitive_(false), ptregs_(ptregs) { |
| if (arg) { |
| TraverseStmt(arg); |
| if (arg->getType()->isPointerType()) |
| is_transitive_ = needs_probe_; |
| } |
| } |
| bool VisitCallExpr(CallExpr *E) { |
| needs_probe_ = false; |
| if (VarDecl *V = dyn_cast<VarDecl>(E->getCalleeDecl())) { |
| needs_probe_ = V->getName() == "bpf_get_current_task"; |
| } |
| return false; |
| } |
| bool VisitDeclRefExpr(DeclRefExpr *E) { |
| if (ptregs_.find(E->getDecl()) != ptregs_.end()) |
| needs_probe_ = true; |
| return true; |
| } |
| bool needs_probe() const { return needs_probe_; } |
| bool is_transitive() const { return is_transitive_; } |
| private: |
| bool needs_probe_; |
| bool is_transitive_; |
| const set<Decl *> &ptregs_; |
| }; |
| |
| // Visit a piece of the AST and mark it as needing probe reads |
| class ProbeSetter : public RecursiveASTVisitor<ProbeSetter> { |
| public: |
| explicit ProbeSetter(set<Decl *> *ptregs) : ptregs_(ptregs) {} |
| bool VisitDeclRefExpr(DeclRefExpr *E) { |
| ptregs_->insert(E->getDecl()); |
| return true; |
| } |
| private: |
| set<Decl *> *ptregs_; |
| }; |
| |
| MapVisitor::MapVisitor(set<Decl *> &m) : m_(m) {} |
| |
| bool MapVisitor::VisitCallExpr(CallExpr *Call) { |
| if (MemberExpr *Memb = dyn_cast<MemberExpr>(Call->getCallee()->IgnoreImplicit())) { |
| StringRef memb_name = Memb->getMemberDecl()->getName(); |
| if (DeclRefExpr *Ref = dyn_cast<DeclRefExpr>(Memb->getBase())) { |
| if (SectionAttr *A = Ref->getDecl()->getAttr<SectionAttr>()) { |
| if (!A->getName().startswith("maps")) |
| return true; |
| |
| if (memb_name == "update" || memb_name == "insert") { |
| if (ProbeChecker(Call->getArg(1), ptregs_).needs_probe()) { |
| m_.insert(Ref->getDecl()); |
| } |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| ProbeVisitor::ProbeVisitor(ASTContext &C, Rewriter &rewriter, set<Decl *> &m) : |
| C(C), rewriter_(rewriter), m_(m) {} |
| |
| bool ProbeVisitor::VisitVarDecl(VarDecl *Decl) { |
| if (Expr *E = Decl->getInit()) { |
| if (ProbeChecker(E, ptregs_).is_transitive() || IsContextMemberExpr(E)) { |
| set_ptreg(Decl); |
| } |
| } |
| return true; |
| } |
| bool ProbeVisitor::VisitCallExpr(CallExpr *Call) { |
| if (FunctionDecl *F = dyn_cast<FunctionDecl>(Call->getCalleeDecl())) { |
| if (F->hasBody()) { |
| unsigned i = 0; |
| for (auto arg : Call->arguments()) { |
| if (ProbeChecker(arg, ptregs_).needs_probe()) |
| ptregs_.insert(F->getParamDecl(i)); |
| ++i; |
| } |
| if (fn_visited_.find(F) == fn_visited_.end()) { |
| fn_visited_.insert(F); |
| TraverseDecl(F); |
| } |
| } |
| } |
| return true; |
| } |
| bool ProbeVisitor::VisitBinaryOperator(BinaryOperator *E) { |
| if (!E->isAssignmentOp()) |
| return true; |
| // copy probe attribute from RHS to LHS if present |
| if (ProbeChecker(E->getRHS(), ptregs_).is_transitive()) { |
| ProbeSetter setter(&ptregs_); |
| setter.TraverseStmt(E->getLHS()); |
| } else if (E->getRHS()->getStmtClass() == Stmt::CallExprClass) { |
| CallExpr *Call = dyn_cast<CallExpr>(E->getRHS()); |
| if (MemberExpr *Memb = dyn_cast<MemberExpr>(Call->getCallee()->IgnoreImplicit())) { |
| StringRef memb_name = Memb->getMemberDecl()->getName(); |
| if (DeclRefExpr *Ref = dyn_cast<DeclRefExpr>(Memb->getBase())) { |
| if (SectionAttr *A = Ref->getDecl()->getAttr<SectionAttr>()) { |
| if (!A->getName().startswith("maps")) |
| return true; |
| |
| if (memb_name == "lookup" || memb_name == "lookup_or_init") { |
| if (m_.find(Ref->getDecl()) != m_.end()) { |
| // Retrieved an external pointer from a map, mark LHS as external pointer. |
| ProbeSetter setter(&ptregs_); |
| setter.TraverseStmt(E->getLHS()); |
| } |
| } |
| } |
| } |
| } |
| } else if (IsContextMemberExpr(E->getRHS())) { |
| ProbeSetter setter(&ptregs_); |
| setter.TraverseStmt(E->getLHS()); |
| } |
| return true; |
| } |
| bool ProbeVisitor::VisitUnaryOperator(UnaryOperator *E) { |
| if (E->getOpcode() != UO_Deref) |
| return true; |
| if (memb_visited_.find(E) != memb_visited_.end()) |
| return true; |
| if (!ProbeChecker(E, ptregs_).needs_probe()) |
| return true; |
| memb_visited_.insert(E); |
| Expr *sub = E->getSubExpr(); |
| string rhs = rewriter_.getRewrittenText(expansionRange(sub->getSourceRange())); |
| string text; |
| text = "({ typeof(" + E->getType().getAsString() + ") _val; __builtin_memset(&_val, 0, sizeof(_val));"; |
| text += " bpf_probe_read(&_val, sizeof(_val), (u64)"; |
| text += rhs + "); _val; })"; |
| rewriter_.ReplaceText(expansionRange(E->getSourceRange()), text); |
| return true; |
| } |
| bool ProbeVisitor::VisitMemberExpr(MemberExpr *E) { |
| if (memb_visited_.find(E) != memb_visited_.end()) return true; |
| |
| // Checks to see if the expression references something that needs to be run |
| // through bpf_probe_read. |
| if (!ProbeChecker(E, ptregs_).needs_probe()) |
| return true; |
| |
| Expr *base; |
| SourceLocation rhs_start, member; |
| bool found = false; |
| for (MemberExpr *M = E; M; M = dyn_cast<MemberExpr>(M->getBase())) { |
| memb_visited_.insert(M); |
| rhs_start = M->getLocEnd(); |
| base = M->getBase(); |
| member = M->getMemberLoc(); |
| if (M->isArrow()) { |
| found = true; |
| break; |
| } |
| } |
| if (!found) |
| return true; |
| if (member.isInvalid()) { |
| error(base->getLocEnd(), "internal error: MemberLoc is invalid while preparing probe rewrite"); |
| return false; |
| } |
| string rhs = rewriter_.getRewrittenText(expansionRange(SourceRange(rhs_start, E->getLocEnd()))); |
| string base_type = base->getType()->getPointeeType().getAsString(); |
| string pre, post; |
| pre = "({ typeof(" + E->getType().getAsString() + ") _val; __builtin_memset(&_val, 0, sizeof(_val));"; |
| pre += " bpf_probe_read(&_val, sizeof(_val), (u64)&"; |
| post = rhs + "); _val; })"; |
| rewriter_.InsertText(E->getLocStart(), pre); |
| rewriter_.ReplaceText(expansionRange(SourceRange(member, E->getLocEnd())), post); |
| return true; |
| } |
| |
| bool ProbeVisitor::IsContextMemberExpr(Expr *E) { |
| if (!E->getType()->isPointerType()) |
| return false; |
| |
| MemberExpr *Memb = dyn_cast<MemberExpr>(E->IgnoreParenCasts()); |
| Expr *base; |
| SourceLocation rhs_start, member; |
| bool found = false; |
| MemberExpr *M; |
| for (M = Memb; M; M = dyn_cast<MemberExpr>(M->getBase())) { |
| memb_visited_.insert(M); |
| rhs_start = M->getLocEnd(); |
| base = M->getBase(); |
| member = M->getMemberLoc(); |
| if (M->isArrow()) { |
| found = true; |
| break; |
| } |
| } |
| if (!found) { |
| return false; |
| } |
| if (member.isInvalid()) { |
| return false; |
| } |
| |
| if (DeclRefExpr *base_expr = dyn_cast<DeclRefExpr>(base->IgnoreImplicit())) { |
| if (base_expr->getDecl() == ctx_) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| SourceRange |
| ProbeVisitor::expansionRange(SourceRange range) { |
| #if LLVM_MAJOR_VERSION >= 7 |
| return rewriter_.getSourceMgr().getExpansionRange(range).getAsRange(); |
| #else |
| return rewriter_.getSourceMgr().getExpansionRange(range); |
| #endif |
| } |
| |
| template <unsigned N> |
| DiagnosticBuilder ProbeVisitor::error(SourceLocation loc, const char (&fmt)[N]) { |
| unsigned int diag_id = C.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, fmt); |
| return C.getDiagnostics().Report(loc, diag_id); |
| } |
| |
| BTypeVisitor::BTypeVisitor(ASTContext &C, BFrontendAction &fe) |
| : C(C), diag_(C.getDiagnostics()), fe_(fe), rewriter_(fe.rewriter()), out_(llvm::errs()) {} |
| |
| bool BTypeVisitor::VisitFunctionDecl(FunctionDecl *D) { |
| const char **calling_conv_regs = get_call_conv(); |
| |
| // put each non-static non-inline function decl in its own section, to be |
| // extracted by the MemoryManager |
| auto real_start_loc = rewriter_.getSourceMgr().getFileLoc(D->getLocStart()); |
| if (fe_.is_rewritable_ext_func(D)) { |
| current_fn_ = D->getName(); |
| string bd = rewriter_.getRewrittenText(expansionRange(D->getSourceRange())); |
| fe_.func_src_.set_src(current_fn_, bd); |
| fe_.func_range_[current_fn_] = expansionRange(D->getSourceRange()); |
| string attr = string("__attribute__((section(\"") + BPF_FN_PREFIX + D->getName().str() + "\")))\n"; |
| rewriter_.InsertText(real_start_loc, 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 = "{"; |
| for (auto arg_it = D->param_begin(); arg_it != D->param_end(); arg_it++) { |
| auto arg = *arg_it; |
| if (arg->getName() == "") { |
| error(arg->getLocEnd(), "arguments to BPF program definition must be named"); |
| return false; |
| } |
| 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(expansionRange(arg->getSourceRange())); |
| arg->addAttr(UnavailableAttr::CreateImplicit(C, "ptregs")); |
| size_t d = fn_args_.size() - 2; |
| const char *reg = calling_conv_regs[d]; |
| preamble += " " + text + " = " + fn_args_[0]->getName().str() + "->" + |
| string(reg) + ";"; |
| } |
| } |
| if (D->param_size() > 1) { |
| rewriter_.ReplaceText( |
| expansionRange(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); |
| } else if (D->hasBody() && |
| rewriter_.getSourceMgr().getFileID(real_start_loc) |
| == rewriter_.getSourceMgr().getMainFileID()) { |
| // rewritable functions that are static should be always treated as helper |
| rewriter_.InsertText(real_start_loc, "__attribute__((always_inline))\n"); |
| } |
| return true; |
| } |
| |
| // Reverse the order of call traversal so that parameters inside of |
| // function calls will get rewritten before the call itself, otherwise |
| // text mangling will result. |
| bool BTypeVisitor::TraverseCallExpr(CallExpr *Call) { |
| for (auto child : Call->children()) |
| if (!TraverseStmt(child)) |
| return false; |
| if (!WalkUpFromCallExpr(Call)) |
| return false; |
| return true; |
| } |
| |
| // convert calls of the type: |
| // table.foo(&key) |
| // to: |
| // bpf_table_foo_elem(bpf_pseudo_fd(table), &key [,&leaf]) |
| bool BTypeVisitor::VisitCallExpr(CallExpr *Call) { |
| // make sure node is a reference to a bpf table, which is assured by the |
| // presence of the section("maps/<typename>") GNU __attribute__ |
| if (MemberExpr *Memb = dyn_cast<MemberExpr>(Call->getCallee()->IgnoreImplicit())) { |
| StringRef memb_name = Memb->getMemberDecl()->getName(); |
| if (DeclRefExpr *Ref = dyn_cast<DeclRefExpr>(Memb->getBase())) { |
| if (SectionAttr *A = Ref->getDecl()->getAttr<SectionAttr>()) { |
| if (!A->getName().startswith("maps")) |
| return true; |
| |
| string args = rewriter_.getRewrittenText(expansionRange(SourceRange(Call->getArg(0)->getLocStart(), |
| Call->getArg(Call->getNumArgs() - 1)->getLocEnd()))); |
| |
| // find the table fd, which was opened at declaration time |
| TableStorage::iterator desc; |
| Path local_path({fe_.id(), Ref->getDecl()->getName()}); |
| Path global_path({Ref->getDecl()->getName()}); |
| if (!fe_.table_storage().Find(local_path, desc)) { |
| if (!fe_.table_storage().Find(global_path, desc)) { |
| error(Ref->getLocEnd(), "bpf_table %0 failed to open") << Ref->getDecl()->getName(); |
| return false; |
| } |
| } |
| string fd = to_string(desc->second.fd); |
| string prefix, suffix; |
| string txt; |
| auto rewrite_start = Call->getLocStart(); |
| auto rewrite_end = Call->getLocEnd(); |
| if (memb_name == "lookup_or_init") { |
| string name = Ref->getDecl()->getName(); |
| string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange())); |
| string arg1 = rewriter_.getRewrittenText(expansionRange(Call->getArg(1)->getSourceRange())); |
| string lookup = "bpf_map_lookup_elem_(bpf_pseudo_fd(1, " + fd + ")"; |
| string update = "bpf_map_update_elem_(bpf_pseudo_fd(1, " + fd + ")"; |
| txt = "({typeof(" + name + ".leaf) *leaf = " + lookup + ", " + arg0 + "); "; |
| txt += "if (!leaf) {"; |
| txt += " " + update + ", " + arg0 + ", " + arg1 + ", BPF_NOEXIST);"; |
| txt += " leaf = " + lookup + ", " + arg0 + ");"; |
| txt += " if (!leaf) return 0;"; |
| txt += "}"; |
| txt += "leaf;})"; |
| } else if (memb_name == "increment") { |
| string name = Ref->getDecl()->getName(); |
| string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange())); |
| string lookup = "bpf_map_lookup_elem_(bpf_pseudo_fd(1, " + fd + ")"; |
| string update = "bpf_map_update_elem_(bpf_pseudo_fd(1, " + fd + ")"; |
| txt = "({ typeof(" + name + ".key) _key = " + arg0 + "; "; |
| txt += "typeof(" + name + ".leaf) *_leaf = " + lookup + ", &_key); "; |
| txt += "if (_leaf) (*_leaf)++; "; |
| if (desc->second.type == BPF_MAP_TYPE_HASH) { |
| txt += "else { typeof(" + name + ".leaf) _zleaf; __builtin_memset(&_zleaf, 0, sizeof(_zleaf)); "; |
| txt += "_zleaf++; "; |
| txt += update + ", &_key, &_zleaf, BPF_NOEXIST); } "; |
| } |
| txt += "})"; |
| } else if (memb_name == "perf_submit") { |
| string name = Ref->getDecl()->getName(); |
| string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange())); |
| string args_other = rewriter_.getRewrittenText(expansionRange(SourceRange(Call->getArg(1)->getLocStart(), |
| Call->getArg(2)->getLocEnd()))); |
| txt = "bpf_perf_event_output(" + arg0 + ", bpf_pseudo_fd(1, " + fd + ")"; |
| txt += ", CUR_CPU_IDENTIFIER, " + args_other + ")"; |
| } else if (memb_name == "perf_submit_skb") { |
| string skb = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange())); |
| string skb_len = rewriter_.getRewrittenText(expansionRange(Call->getArg(1)->getSourceRange())); |
| string meta = rewriter_.getRewrittenText(expansionRange(Call->getArg(2)->getSourceRange())); |
| string meta_len = rewriter_.getRewrittenText(expansionRange(Call->getArg(3)->getSourceRange())); |
| txt = "bpf_perf_event_output(" + |
| skb + ", " + |
| "bpf_pseudo_fd(1, " + fd + "), " + |
| "((__u64)" + skb_len + " << 32) | BPF_F_CURRENT_CPU, " + |
| meta + ", " + |
| meta_len + ");"; |
| } else if (memb_name == "get_stackid") { |
| if (desc->second.type == BPF_MAP_TYPE_STACK_TRACE) { |
| string arg0 = |
| rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange())); |
| txt = "bcc_get_stackid("; |
| txt += "bpf_pseudo_fd(1, " + fd + "), " + arg0; |
| rewrite_end = Call->getArg(0)->getLocEnd(); |
| } else { |
| error(Call->getLocStart(), "get_stackid only available on stacktrace maps"); |
| return false; |
| } |
| } else { |
| if (memb_name == "lookup") { |
| prefix = "bpf_map_lookup_elem"; |
| suffix = ")"; |
| } else if (memb_name == "update") { |
| prefix = "bpf_map_update_elem"; |
| suffix = ", BPF_ANY)"; |
| } else if (memb_name == "insert") { |
| if (desc->second.type == BPF_MAP_TYPE_ARRAY) { |
| warning(Call->getLocStart(), "all element of an array already exist; insert() will have no effect"); |
| } |
| prefix = "bpf_map_update_elem"; |
| suffix = ", BPF_NOEXIST)"; |
| } else if (memb_name == "delete") { |
| prefix = "bpf_map_delete_elem"; |
| suffix = ")"; |
| } else if (memb_name == "call") { |
| prefix = "bpf_tail_call_"; |
| suffix = ")"; |
| } else if (memb_name == "perf_read") { |
| prefix = "bpf_perf_event_read"; |
| suffix = ")"; |
| } else if (memb_name == "perf_counter_value") { |
| prefix = "bpf_perf_event_read_value"; |
| suffix = ")"; |
| } else if (memb_name == "check_current_task") { |
| prefix = "bpf_current_task_under_cgroup"; |
| suffix = ")"; |
| } else { |
| error(Call->getLocStart(), "invalid bpf_table operation %0") << memb_name; |
| return false; |
| } |
| prefix += "((void *)bpf_pseudo_fd(1, " + fd + "), "; |
| |
| txt = prefix + args + suffix; |
| } |
| if (!rewriter_.isRewritable(rewrite_start) || !rewriter_.isRewritable(rewrite_end)) { |
| error(Call->getLocStart(), "cannot use map function inside a macro"); |
| return false; |
| } |
| rewriter_.ReplaceText(expansionRange(SourceRange(rewrite_start, rewrite_end)), txt); |
| return true; |
| } |
| } |
| } else if (Call->getCalleeDecl()) { |
| NamedDecl *Decl = dyn_cast<NamedDecl>(Call->getCalleeDecl()); |
| if (!Decl) return true; |
| if (AsmLabelAttr *A = Decl->getAttr<AsmLabelAttr>()) { |
| // Functions with the tag asm("llvm.bpf.extra") are implemented in the |
| // rewriter rather than as a macro since they may also include nested |
| // rewrites, and clang::Rewriter does not support rewrites in macros, |
| // unless one preprocesses the entire source file. |
| if (A->getLabel() == "llvm.bpf.extra") { |
| if (!rewriter_.isRewritable(Call->getLocStart())) { |
| error(Call->getLocStart(), "cannot use builtin inside a macro"); |
| return false; |
| } |
| |
| vector<string> args; |
| for (auto arg : Call->arguments()) |
| args.push_back(rewriter_.getRewrittenText(expansionRange(arg->getSourceRange()))); |
| |
| string text; |
| if (Decl->getName() == "incr_cksum_l3") { |
| text = "bpf_l3_csum_replace_(" + fn_args_[0]->getName().str() + ", (u64)"; |
| text += args[0] + ", " + args[1] + ", " + args[2] + ", sizeof(" + args[2] + "))"; |
| rewriter_.ReplaceText(expansionRange(Call->getSourceRange()), text); |
| } else if (Decl->getName() == "incr_cksum_l4") { |
| text = "bpf_l4_csum_replace_(" + fn_args_[0]->getName().str() + ", (u64)"; |
| text += args[0] + ", " + args[1] + ", " + args[2]; |
| text += ", ((" + args[3] + " & 0x1) << 4) | sizeof(" + args[2] + "))"; |
| rewriter_.ReplaceText(expansionRange(Call->getSourceRange()), text); |
| } else if (Decl->getName() == "bpf_trace_printk") { |
| checkFormatSpecifiers(args[0], Call->getArg(0)->getLocStart()); |
| // #define bpf_trace_printk(fmt, args...) |
| // ({ char _fmt[] = fmt; bpf_trace_printk_(_fmt, sizeof(_fmt), args...); }) |
| text = "({ char _fmt[] = " + args[0] + "; bpf_trace_printk_(_fmt, sizeof(_fmt)"; |
| if (args.size() <= 1) { |
| text += "); })"; |
| rewriter_.ReplaceText(expansionRange(Call->getSourceRange()), text); |
| } else { |
| rewriter_.ReplaceText(expansionRange(SourceRange(Call->getLocStart(), Call->getArg(0)->getLocEnd())), text); |
| rewriter_.InsertTextAfter(Call->getLocEnd(), "); }"); |
| } |
| } else if (Decl->getName() == "bpf_num_cpus") { |
| int numcpu = sysconf(_SC_NPROCESSORS_ONLN); |
| if (numcpu <= 0) |
| numcpu = 1; |
| text = to_string(numcpu); |
| rewriter_.ReplaceText(expansionRange(Call->getSourceRange()), text); |
| } else if (Decl->getName() == "bpf_usdt_readarg_p") { |
| text = "({ u64 __addr = 0x0; "; |
| text += "_bpf_readarg_" + current_fn_ + "_" + args[0] + "(" + |
| args[1] + ", &__addr, sizeof(__addr));"; |
| text += "bpf_probe_read(" + args[2] + ", " + args[3] + |
| ", (void *)__addr);"; |
| text += "})"; |
| rewriter_.ReplaceText(expansionRange(Call->getSourceRange()), text); |
| } else if (Decl->getName() == "bpf_usdt_readarg") { |
| text = "_bpf_readarg_" + current_fn_ + "_" + args[0] + "(" + args[1] + |
| ", " + args[2] + ", sizeof(*(" + args[2] + ")))"; |
| rewriter_.ReplaceText(expansionRange(Call->getSourceRange()), text); |
| } |
| } |
| } else if (FunctionDecl *F = dyn_cast<FunctionDecl>(Decl)) { |
| if (F->isExternallyVisible() && !F->getBuiltinID()) { |
| auto start_loc = rewriter_.getSourceMgr().getFileLoc(Decl->getLocStart()); |
| if (rewriter_.getSourceMgr().getFileID(start_loc) |
| == rewriter_.getSourceMgr().getMainFileID()) { |
| error(Call->getLocStart(), "cannot call non-static helper function"); |
| return false; |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool BTypeVisitor::checkFormatSpecifiers(const string& fmt, SourceLocation loc) { |
| unsigned nb_specifiers = 0, i, j; |
| bool has_s = false; |
| for (i = 0; i < fmt.length(); i++) { |
| if (!isascii(fmt[i]) || (!isprint(fmt[i]) && !isspace(fmt[i]))) { |
| warning(loc.getLocWithOffset(i), "unrecognized character"); |
| return false; |
| } |
| if (fmt[i] != '%') |
| continue; |
| if (nb_specifiers >= 3) { |
| warning(loc.getLocWithOffset(i), "cannot use more than 3 conversion specifiers"); |
| return false; |
| } |
| nb_specifiers++; |
| i++; |
| if (fmt[i] == 'l') { |
| i++; |
| } else if (fmt[i] == 'p' || fmt[i] == 's') { |
| i++; |
| if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0) { |
| warning(loc.getLocWithOffset(i - 2), |
| "only %%d %%u %%x %%ld %%lu %%lx %%lld %%llu %%llx %%p %%s conversion specifiers allowed"); |
| return false; |
| } |
| if (fmt[i - 1] == 's') { |
| if (has_s) { |
| warning(loc.getLocWithOffset(i - 2), "cannot use several %%s conversion specifiers"); |
| return false; |
| } |
| has_s = true; |
| } |
| continue; |
| } |
| j = 1; |
| if (fmt[i] == 'l') { |
| i++; |
| j++; |
| } |
| if (fmt[i] != 'd' && fmt[i] != 'u' && fmt[i] != 'x') { |
| warning(loc.getLocWithOffset(i - j), |
| "only %%d %%u %%x %%ld %%lu %%lx %%lld %%llu %%llx %%p %%s conversion specifiers allowed"); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool BTypeVisitor::VisitBinaryOperator(BinaryOperator *E) { |
| if (!E->isAssignmentOp()) |
| return true; |
| Expr *LHS = E->getLHS()->IgnoreImplicit(); |
| if (MemberExpr *Memb = dyn_cast<MemberExpr>(LHS)) { |
| if (DeclRefExpr *Base = dyn_cast<DeclRefExpr>(Memb->getBase()->IgnoreImplicit())) { |
| if (DeprecatedAttr *A = Base->getDecl()->getAttr<DeprecatedAttr>()) { |
| if (A->getMessage() == "packet") { |
| if (FieldDecl *F = dyn_cast<FieldDecl>(Memb->getMemberDecl())) { |
| if (!rewriter_.isRewritable(E->getLocStart())) { |
| error(E->getLocStart(), "cannot use \"packet\" header type inside a macro"); |
| return false; |
| } |
| uint64_t ofs = C.getFieldOffset(F); |
| uint64_t sz = F->isBitField() ? F->getBitWidthValue(C) : C.getTypeSize(F->getType()); |
| string base = rewriter_.getRewrittenText(expansionRange(Base->getSourceRange())); |
| string text = "bpf_dins_pkt(" + fn_args_[0]->getName().str() + ", (u64)" + base + "+" + to_string(ofs >> 3) |
| + ", " + to_string(ofs & 0x7) + ", " + to_string(sz) + ","; |
| rewriter_.ReplaceText(expansionRange(SourceRange(E->getLocStart(), E->getOperatorLoc())), text); |
| rewriter_.InsertTextAfterToken(E->getLocEnd(), ")"); |
| } |
| } |
| } |
| } |
| } |
| return true; |
| } |
| bool BTypeVisitor::VisitImplicitCastExpr(ImplicitCastExpr *E) { |
| // use dext only for RValues |
| if (E->getCastKind() != CK_LValueToRValue) |
| return true; |
| MemberExpr *Memb = dyn_cast<MemberExpr>(E->IgnoreImplicit()); |
| if (!Memb) |
| return true; |
| Expr *Base = Memb->getBase()->IgnoreImplicit(); |
| if (DeclRefExpr *Ref = dyn_cast<DeclRefExpr>(Base)) { |
| if (DeprecatedAttr *A = Ref->getDecl()->getAttr<DeprecatedAttr>()) { |
| if (A->getMessage() == "packet") { |
| if (FieldDecl *F = dyn_cast<FieldDecl>(Memb->getMemberDecl())) { |
| if (!rewriter_.isRewritable(E->getLocStart())) { |
| error(E->getLocStart(), "cannot use \"packet\" header type inside a macro"); |
| return false; |
| } |
| uint64_t ofs = C.getFieldOffset(F); |
| uint64_t sz = F->isBitField() ? F->getBitWidthValue(C) : C.getTypeSize(F->getType()); |
| string text = "bpf_dext_pkt(" + fn_args_[0]->getName().str() + ", (u64)" + Ref->getDecl()->getName().str() + "+" |
| + to_string(ofs >> 3) + ", " + to_string(ofs & 0x7) + ", " + to_string(sz) + ")"; |
| rewriter_.ReplaceText(expansionRange(E->getSourceRange()), text); |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| SourceRange |
| BTypeVisitor::expansionRange(SourceRange range) { |
| #if LLVM_MAJOR_VERSION >= 7 |
| return rewriter_.getSourceMgr().getExpansionRange(range).getAsRange(); |
| #else |
| return rewriter_.getSourceMgr().getExpansionRange(range); |
| #endif |
| } |
| |
| template <unsigned N> |
| DiagnosticBuilder BTypeVisitor::error(SourceLocation loc, const char (&fmt)[N]) { |
| unsigned int diag_id = C.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, fmt); |
| return C.getDiagnostics().Report(loc, diag_id); |
| } |
| |
| template <unsigned N> |
| DiagnosticBuilder BTypeVisitor::warning(SourceLocation loc, const char (&fmt)[N]) { |
| unsigned int diag_id = C.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Warning, fmt); |
| return C.getDiagnostics().Report(loc, diag_id); |
| } |
| |
| // Open table FDs when bpf tables (as denoted by section("maps*") attribute) |
| // are declared. |
| bool BTypeVisitor::VisitVarDecl(VarDecl *Decl) { |
| const RecordType *R = Decl->getType()->getAs<RecordType>(); |
| if (SectionAttr *A = Decl->getAttr<SectionAttr>()) { |
| if (!A->getName().startswith("maps")) |
| return true; |
| if (!R) { |
| error(Decl->getLocEnd(), "invalid type for bpf_table, expect struct"); |
| return false; |
| } |
| const RecordDecl *RD = R->getDecl()->getDefinition(); |
| |
| TableDesc table; |
| TableStorage::iterator table_it; |
| table.name = Decl->getName(); |
| Path local_path({fe_.id(), table.name}); |
| Path global_path({table.name}); |
| QualType key_type, leaf_type; |
| |
| unsigned i = 0; |
| for (auto F : RD->fields()) { |
| if (F->getType().getTypePtr()->isIncompleteType()) { |
| error(F->getLocStart(), "unknown type"); |
| return false; |
| } |
| |
| size_t sz = C.getTypeSize(F->getType()) >> 3; |
| if (F->getName() == "key") { |
| if (sz == 0) { |
| error(F->getLocStart(), "invalid zero-sized leaf"); |
| return false; |
| } |
| table.key_size = sz; |
| key_type = F->getType(); |
| } else if (F->getName() == "leaf") { |
| if (sz == 0) { |
| error(F->getLocStart(), "invalid zero-sized leaf"); |
| return false; |
| } |
| table.leaf_size = sz; |
| leaf_type = F->getType(); |
| } else if (F->getName() == "max_entries") { |
| unsigned idx = F->getFieldIndex(); |
| if (auto I = dyn_cast_or_null<InitListExpr>(Decl->getInit())) { |
| llvm::APSInt res; |
| if (I->getInit(idx)->EvaluateAsInt(res, C)) { |
| table.max_entries = res.getExtValue(); |
| } |
| } |
| } else if (F->getName() == "flags") { |
| unsigned idx = F->getFieldIndex(); |
| if (auto I = dyn_cast_or_null<InitListExpr>(Decl->getInit())) { |
| llvm::APSInt res; |
| if (I->getInit(idx)->EvaluateAsInt(res, C)) { |
| table.flags = res.getExtValue(); |
| } |
| } |
| } |
| ++i; |
| } |
| |
| bpf_map_type map_type = BPF_MAP_TYPE_UNSPEC; |
| if (A->getName() == "maps/hash") { |
| map_type = BPF_MAP_TYPE_HASH; |
| } else if (A->getName() == "maps/array") { |
| map_type = BPF_MAP_TYPE_ARRAY; |
| } else if (A->getName() == "maps/percpu_hash") { |
| map_type = BPF_MAP_TYPE_PERCPU_HASH; |
| } else if (A->getName() == "maps/percpu_array") { |
| map_type = BPF_MAP_TYPE_PERCPU_ARRAY; |
| } else if (A->getName() == "maps/lru_hash") { |
| map_type = BPF_MAP_TYPE_LRU_HASH; |
| } else if (A->getName() == "maps/lru_percpu_hash") { |
| map_type = BPF_MAP_TYPE_LRU_PERCPU_HASH; |
| } else if (A->getName() == "maps/lpm_trie") { |
| map_type = BPF_MAP_TYPE_LPM_TRIE; |
| } else if (A->getName() == "maps/histogram") { |
| map_type = BPF_MAP_TYPE_HASH; |
| if (key_type->isSpecificBuiltinType(BuiltinType::Int)) |
| map_type = BPF_MAP_TYPE_ARRAY; |
| if (!leaf_type->isSpecificBuiltinType(BuiltinType::ULongLong)) |
| error(Decl->getLocStart(), "histogram leaf type must be u64, got %0") << leaf_type; |
| } else if (A->getName() == "maps/prog") { |
| map_type = BPF_MAP_TYPE_PROG_ARRAY; |
| } else if (A->getName() == "maps/perf_output") { |
| map_type = BPF_MAP_TYPE_PERF_EVENT_ARRAY; |
| int numcpu = get_possible_cpus().size(); |
| if (numcpu <= 0) |
| numcpu = 1; |
| table.max_entries = numcpu; |
| } else if (A->getName() == "maps/perf_array") { |
| map_type = BPF_MAP_TYPE_PERF_EVENT_ARRAY; |
| } else if (A->getName() == "maps/cgroup_array") { |
| map_type = BPF_MAP_TYPE_CGROUP_ARRAY; |
| } else if (A->getName() == "maps/stacktrace") { |
| map_type = BPF_MAP_TYPE_STACK_TRACE; |
| } else if (A->getName() == "maps/extern") { |
| if (!fe_.table_storage().Find(global_path, table_it)) { |
| error(Decl->getLocStart(), "reference to undefined table"); |
| return false; |
| } |
| table = table_it->second.dup(); |
| table.is_extern = true; |
| } else if (A->getName() == "maps/export") { |
| if (table.name.substr(0, 2) == "__") |
| table.name = table.name.substr(2); |
| Path local_path({fe_.id(), table.name}); |
| Path global_path({table.name}); |
| if (!fe_.table_storage().Find(local_path, table_it)) { |
| error(Decl->getLocStart(), "reference to undefined table"); |
| return false; |
| } |
| fe_.table_storage().Insert(global_path, table_it->second.dup()); |
| return true; |
| } |
| |
| if (!table.is_extern) { |
| if (map_type == BPF_MAP_TYPE_UNSPEC) { |
| error(Decl->getLocStart(), "unsupported map type: %0") << A->getName(); |
| return false; |
| } |
| |
| table.type = map_type; |
| table.fd = bpf_create_map(map_type, table.name.c_str(), |
| table.key_size, table.leaf_size, |
| table.max_entries, table.flags); |
| } |
| if (table.fd < 0) { |
| error(Decl->getLocStart(), "could not open bpf map: %0\nis %1 map type enabled in your kernel?") << |
| strerror(errno) << A->getName(); |
| return false; |
| } |
| |
| if (!table.is_extern) |
| fe_.table_storage().VisitMapType(table, C, key_type, leaf_type); |
| fe_.table_storage().Insert(local_path, move(table)); |
| } else if (const PointerType *P = Decl->getType()->getAs<PointerType>()) { |
| // if var is a pointer to a packet type, clone the annotation into the var |
| // decl so that the packet dext/dins rewriter can catch it |
| if (const RecordType *RT = P->getPointeeType()->getAs<RecordType>()) { |
| if (const RecordDecl *RD = RT->getDecl()->getDefinition()) { |
| if (DeprecatedAttr *DA = RD->getAttr<DeprecatedAttr>()) { |
| if (DA->getMessage() == "packet") { |
| Decl->addAttr(DA->clone(C)); |
| } |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| // First traversal of AST to retrieve maps with external pointers. |
| BTypeConsumer::BTypeConsumer(ASTContext &C, BFrontendAction &fe, |
| Rewriter &rewriter, set<Decl *> &m) |
| : fe_(fe), |
| map_visitor_(m), |
| btype_visitor_(C, fe), |
| probe_visitor_(C, rewriter, m) {} |
| |
| bool BTypeConsumer::HandleTopLevelDecl(DeclGroupRef Group) { |
| for (auto D : Group) { |
| if (FunctionDecl *F = dyn_cast<FunctionDecl>(D)) { |
| if (fe_.is_rewritable_ext_func(F)) { |
| for (auto arg : F->parameters()) { |
| if (arg != F->getParamDecl(0) && !arg->getType()->isFundamentalType()) { |
| map_visitor_.set_ptreg(arg); |
| } |
| } |
| map_visitor_.TraverseDecl(D); |
| } |
| } |
| } |
| return true; |
| } |
| |
| void BTypeConsumer::HandleTranslationUnit(ASTContext &Context) { |
| DeclContext::decl_iterator it; |
| DeclContext *DC = TranslationUnitDecl::castToDeclContext(Context.getTranslationUnitDecl()); |
| |
| /** |
| * ProbeVisitor's traversal runs after an entire translation unit has been parsed. |
| * to make sure maps with external pointers have been identified. |
| */ |
| for (it = DC->decls_begin(); it != DC->decls_end(); it++) { |
| Decl *D = *it; |
| if (FunctionDecl *F = dyn_cast<FunctionDecl>(D)) { |
| if (fe_.is_rewritable_ext_func(F)) { |
| for (auto arg : F->parameters()) { |
| if (arg == F->getParamDecl(0)) { |
| probe_visitor_.set_ctx(arg); |
| } else if (!arg->getType()->isFundamentalType()) { |
| probe_visitor_.set_ptreg(arg); |
| } |
| } |
| probe_visitor_.TraverseDecl(D); |
| } |
| } |
| |
| btype_visitor_.TraverseDecl(D); |
| } |
| } |
| |
| BFrontendAction::BFrontendAction(llvm::raw_ostream &os, unsigned flags, |
| TableStorage &ts, const std::string &id, |
| const std::string &main_path, |
| FuncSource &func_src, std::string &mod_src) |
| : os_(os), |
| flags_(flags), |
| ts_(ts), |
| id_(id), |
| rewriter_(new Rewriter), |
| main_path_(main_path), |
| func_src_(func_src), |
| mod_src_(mod_src) {} |
| |
| bool BFrontendAction::is_rewritable_ext_func(FunctionDecl *D) { |
| StringRef file_name = rewriter_->getSourceMgr().getFilename(D->getLocStart()); |
| return (D->isExternallyVisible() && D->hasBody() && |
| (file_name.empty() || file_name == main_path_)); |
| } |
| |
| void BFrontendAction::EndSourceFileAction() { |
| if (flags_ & DEBUG_PREPROCESSOR) |
| rewriter_->getEditBuffer(rewriter_->getSourceMgr().getMainFileID()).write(llvm::errs()); |
| if (flags_ & DEBUG_SOURCE) { |
| llvm::raw_string_ostream tmp_os(mod_src_); |
| rewriter_->getEditBuffer(rewriter_->getSourceMgr().getMainFileID()) |
| .write(tmp_os); |
| } |
| |
| for (auto func : func_range_) { |
| auto f = func.first; |
| string bd = rewriter_->getRewrittenText(func_range_[f]); |
| func_src_.set_src_rewritten(f, bd); |
| } |
| rewriter_->getEditBuffer(rewriter_->getSourceMgr().getMainFileID()).write(os_); |
| os_.flush(); |
| } |
| |
| unique_ptr<ASTConsumer> BFrontendAction::CreateASTConsumer(CompilerInstance &Compiler, llvm::StringRef InFile) { |
| rewriter_->setSourceMgr(Compiler.getSourceManager(), Compiler.getLangOpts()); |
| vector<unique_ptr<ASTConsumer>> consumers; |
| consumers.push_back(unique_ptr<ASTConsumer>(new BTypeConsumer(Compiler.getASTContext(), *this, *rewriter_, m_))); |
| return unique_ptr<ASTConsumer>(new MultiplexConsumer(std::move(consumers))); |
| } |
| |
| } |