logprintf.cpp

// Copyright (c) 2023 Bitcoin Developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "logprintf.h"

#include <clang/AST/ASTContext.h>
#include <clang/ASTMatchers/ASTMatchFinder.h>


namespace {
AST_MATCHER(clang::StringLiteral, unterminated) {
    size_t len = Node.getLength();
    if(len > 0 && Node.getCodeUnit(len-1) == '\n') {
        return false;
    }
    return true;
}
} // namespace

namespace bitcoin {

void LogPrintfCheck::registerMatchers(clang::ast_matchers::MatchFinder *finder)
{
    using namespace clang::ast_matchers;

    /*
      Logprintf(..., ..., ..., ..., ..., "foo", ...)
    */

    finder->addMatcher(
      callExpr(
        callee(functionDecl(hasName("LogPrintf_"))),
        hasArgument(5, stringLiteral(unterminated()).bind("logstring"))
      ),
    this);

    /*
      CWallet wallet;
      auto walletptr = &wallet;
      wallet.WalletLogPrintf("foo");
      wallet->WalletLogPrintf("foo");
    */
    finder->addMatcher(
      cxxMemberCallExpr(
        thisPointerType(qualType(hasDeclaration(cxxRecordDecl(hasName("CWallet"))))),
        callee(cxxMethodDecl(hasName("WalletLogPrintf"))),
        hasArgument(0, stringLiteral(unterminated()).bind("logstring")))
    , this);
}

void LogPrintfCheck::check(const clang::ast_matchers::MatchFinder::MatchResult &Result)
{
    if (const clang::StringLiteral* lit = Result.Nodes.getNodeAs<clang::StringLiteral>("logstring")) {
        const clang::ASTContext& ctx = *Result.Context;
        const auto user_diag = diag(lit->getEndLoc(), "Unterminated format string used with LogPrintf");
        const auto& loc = lit->getLocationOfByte(lit->getByteLength(), *Result.SourceManager, ctx.getLangOpts(), ctx.getTargetInfo());
        user_diag << clang::FixItHint::CreateInsertion(loc, "\\n");
    }
}

} // namespace bitcoin