agent_lexer.ll 19.6 KB
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/* Copyright (C) 2017 Internet Systems Consortium, Inc. ("ISC")

   This Source Code Form is subject to the terms of the Mozilla Public
   License, v. 2.0. If a copy of the MPL was not distributed with this
   file, You can obtain one at http://mozilla.org/MPL/2.0/. */

%{ /* -*- C++ -*- */
#include <cerrno>
#include <climits>
#include <cstdlib>
#include <string>
#include <agent/parser_context.h>
#include <asiolink/io_address.h>
#include <boost/lexical_cast.hpp>
#include <exceptions/exceptions.h>
#include <cc/dhcp_config_error.h>

// Work around an incompatibility in flex (at least versions
// 2.5.31 through 2.5.33): it generates code that does
// not conform to C89.  See Debian bug 333231
// <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>.
# undef yywrap
# define yywrap() 1

namespace {

bool start_token_flag = false;

isc::agent::ParserContext::ParserType start_token_value;
unsigned int comment_start_line = 0;

using namespace isc;
using isc::agent::AgentParser;

};

// To avoid the call to exit... oops!
#define YY_FATAL_ERROR(msg) isc::agent::ParserContext::fatal(msg)
%}

/* noyywrap disables automatic rewinding for the next file to parse. Since we
   always parse only a single string, there's no need to do any wraps. And
   using yywrap requires linking with -lfl, which provides the default yywrap
   implementation that always returns 1 anyway. */
%option noyywrap

/* nounput simplifies the lexer, by removing support for putting a character
   back into the input stream. We never use such capability anyway. */
%option nounput

/* batch means that we'll never use the generated lexer interactively. */
%option batch

/* avoid to get static global variables to remain with C++. */
/* in last resort %option reentrant */

/* Enables debug mode. To see the debug messages, one needs to also set
   yy_flex_debug to 1, then the debug messages will be printed on stderr. */
%option debug

/* I have no idea what this option does, except it was specified in the bison
   examples and Postgres folks added it to remove gcc 4.3 warnings. Let's
   be on the safe side and keep it. */
%option noinput

%x COMMENT
%x DIR_ENTER DIR_INCLUDE DIR_EXIT

/* These are not token expressions yet, just convenience expressions that
   can be used during actual token definitions. Note some can match
   incorrect inputs (e.g., IP addresses) which must be checked. */
int   \-?[0-9]+
blank [ \t\r]

UnicodeEscapeSequence           u[0-9A-Fa-f]{4}
JSONEscapeCharacter             ["\\/bfnrt]
JSONEscapeSequence              {JSONEscapeCharacter}|{UnicodeEscapeSequence}
JSONStandardCharacter           [^\x00-\x1f"\\]
JSONStringCharacter             {JSONStandardCharacter}|\\{JSONEscapeSequence}
JSONString                      \"{JSONStringCharacter}*\"

/* for errors */

BadUnicodeEscapeSequence        u[0-9A-Fa-f]{0,3}[^0-9A-Fa-f]
BadJSONEscapeSequence           [^"\\/bfnrtu]|{BadUnicodeEscapeSequence}
ControlCharacter                [\x00-\x1f]
ControlCharacterFill            [^"\\]|\\{JSONEscapeSequence}

%{
// This code run each time a pattern is matched. It updates the location
// by moving it ahead by yyleng bytes. yyleng specifies the length of the
// currently matched token.
#define YY_USER_ACTION  driver.loc_.columns(yyleng);
%}

%%

%{
    // This part of the code is copied over to the verbatim to the top
    // of the generated yylex function. Explanation:
    // http://www.gnu.org/software/bison/manual/html_node/Multiple-start_002dsymbols.html

    // Code run each time yylex is called.
    driver.loc_.step();

    // We currently have 3 points of entries defined:
    // START_JSON - which expects any valid JSON
    // START_AGENT - which expects full configuration (with outer map and Control-agent
    //               object in it.
    // START_SUB_AGENT - which expects only content of the Control-agent, this is
    //                   primarily useful for testing.
    if (start_token_flag) {
        start_token_flag = false;
        switch (start_token_value) {
        case ParserContext::PARSER_JSON:
        default:
            return isc::agent::AgentParser::make_START_JSON(driver.loc_);
        case ParserContext::PARSER_AGENT:
            return isc::agent::AgentParser::make_START_AGENT(driver.loc_);
        case ParserContext::PARSER_SUB_AGENT:
            return isc::agent::AgentParser::make_START_SUB_AGENT(driver.loc_);
        }
    }
%}

#.* ;

"//"(.*) ;

"/*" {
  BEGIN(COMMENT);
  comment_start_line = driver.loc_.end.line;;
}

<COMMENT>"*/" BEGIN(INITIAL);
<COMMENT>. ;
<COMMENT><<EOF>> {
    isc_throw(ParseError, "Comment not closed. (/* in line " << comment_start_line);
}

"<?" BEGIN(DIR_ENTER);
<DIR_ENTER>"include" BEGIN(DIR_INCLUDE);
<DIR_INCLUDE>\"([^\"\n])+\" {
    // Include directive.

    // Extract the filename.
    std::string tmp(yytext+1);
    tmp.resize(tmp.size() - 1);

    driver.includeFile(tmp);
}
<DIR_ENTER,DIR_INCLUDE,DIR_EXIT><<EOF>> {
    isc_throw(ParseError, "Directive not closed.");
}
<DIR_EXIT>"?>" BEGIN(INITIAL);


<*>{blank}+   {
    // Ok, we found a with space. Let's ignore it and update loc variable.
    driver.loc_.step();
}

<*>[\n]+      {
    // Newline found. Let's update the location and continue.
    driver.loc_.lines(yyleng);
    driver.loc_.step();
}


\"Control-agent\" {
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    switch(driver.ctx_) {
    case ParserContext::CONFIG:
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        return AgentParser::make_CONTROL_AGENT(driver.loc_);
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    default:
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        return AgentParser::make_STRING("Control-agent", driver.loc_);
    }
}

\"http-host\" {
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    switch(driver.ctx_) {
    case ParserContext::AGENT:
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        return AgentParser::make_HTTP_HOST(driver.loc_);
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    default:
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        return AgentParser::make_STRING("http-host", driver.loc_);
    }
}

\"http-port\" {
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    switch(driver.ctx_) {
    case ParserContext::AGENT:
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        return AgentParser::make_HTTP_PORT(driver.loc_);
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    default:
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        return AgentParser::make_STRING("http-port", driver.loc_);
    }
}

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\"control-sockets\" {
    switch(driver.ctx_) {
    case ParserContext::AGENT:
        return AgentParser::make_CONTROL_SOCKETS(driver.loc_);
    default:
        return AgentParser::make_STRING("control-sockets", driver.loc_);
    }
}

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\"dhcp4-server\" {
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    switch(driver.ctx_) {
    case ParserContext::CONTROL_SOCKETS:
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        return AgentParser::make_DHCP4_SERVER(driver.loc_);
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    default:
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        return AgentParser::make_STRING("dhcp4-server", driver.loc_);
    }
}

\"dhcp6-server\" {
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    switch(driver.ctx_) {
    case ParserContext::CONTROL_SOCKETS:
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        return AgentParser::make_DHCP6_SERVER(driver.loc_);
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    default:
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        return AgentParser::make_STRING("dhcp6-server", driver.loc_);
    }
}

\"d2-server\" {
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    switch(driver.ctx_) {
    case ParserContext::CONTROL_SOCKETS:
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        return AgentParser::make_D2_SERVER(driver.loc_);
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    default:
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        return AgentParser::make_STRING("d2-server", driver.loc_);
    }
}

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\"socket-name\" {
    switch(driver.ctx_) {
    case ParserContext::SERVER:
        return AgentParser::make_SOCKET_NAME(driver.loc_);
    default:
        return AgentParser::make_STRING("socket-name", driver.loc_);
    }
}

\"socket-type\" {
    switch(driver.ctx_) {
    case ParserContext::SERVER:
        return AgentParser::make_SOCKET_TYPE(driver.loc_);
    default:
        return AgentParser::make_STRING("socket-type", driver.loc_);
    }
}

\"unix\" {
    switch(driver.ctx_) {
    case ParserContext::SOCKET_TYPE:
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        return AgentParser::make_UNIX(driver.loc_);
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    default:
        return AgentParser::make_STRING("unix", driver.loc_);
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    }
}

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\"hooks-libraries\" {
    switch(driver.ctx_) {
    case ParserContext::AGENT:
        return AgentParser::make_HOOKS_LIBRARIES(driver.loc_);
    default:
        return AgentParser::make_STRING("hooks-libraries", driver.loc_);
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    }
}

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\"library\" {
    switch(driver.ctx_) {
    case ParserContext::HOOKS_LIBRARIES:
        return AgentParser::make_LIBRARY(driver.loc_);
    default:
        return AgentParser::make_STRING("library", driver.loc_);
    }
}

\"parameters\" {
    switch(driver.ctx_) {
    case ParserContext::HOOKS_LIBRARIES:
        return AgentParser::make_PARAMETERS(driver.loc_);
    default:
        return AgentParser::make_STRING("parameters", driver.loc_);
    }
}
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\"Logging\" {
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    switch(driver.ctx_) {
    case ParserContext::CONFIG:
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        return AgentParser::make_LOGGING(driver.loc_);
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    default:
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        return AgentParser::make_STRING("Logging", driver.loc_);
    }
}

\"loggers\" {
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    switch(driver.ctx_) {
    case ParserContext::LOGGING:
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        return AgentParser::make_LOGGERS(driver.loc_);
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    default:
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        return AgentParser::make_STRING("loggers", driver.loc_);
    }
}

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\"name\" {
    switch(driver.ctx_) {
    case ParserContext::LOGGERS:
        return AgentParser::make_NAME(driver.loc_);
    default:
        return AgentParser::make_STRING("name", driver.loc_);
    }
}

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\"output_options\" {
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    switch(driver.ctx_) {
    case ParserContext::LOGGERS:
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        return AgentParser::make_OUTPUT_OPTIONS(driver.loc_);
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    default:
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        return AgentParser::make_STRING("output_options", driver.loc_);
    }
}

\"output\" {
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    switch(driver.ctx_) {
    case ParserContext::OUTPUT_OPTIONS:
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        return AgentParser::make_OUTPUT(driver.loc_);
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    default:
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        return AgentParser::make_STRING("output", driver.loc_);
    }
}

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\"flush\" {
    switch(driver.ctx_) {
    case ParserContext::OUTPUT_OPTIONS:
        return AgentParser::make_FLUSH(driver.loc_);
    default:
        return AgentParser::make_STRING("flush", driver.loc_);
    }
}

\"maxsize\" {
    switch(driver.ctx_) {
    case ParserContext::OUTPUT_OPTIONS:
        return AgentParser::make_MAXSIZE(driver.loc_);
    default:
        return AgentParser::make_STRING("maxsize", driver.loc_);
    }
}

\"maxver\" {
    switch(driver.ctx_) {
    case ParserContext::OUTPUT_OPTIONS:
        return AgentParser::make_MAXVER(driver.loc_);
    default:
        return AgentParser::make_STRING("maxver", driver.loc_);
    }
}

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\"debuglevel\" {
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    switch(driver.ctx_) {
    case ParserContext::LOGGERS:
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        return AgentParser::make_DEBUGLEVEL(driver.loc_);
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    default:
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        return AgentParser::make_STRING("debuglevel", driver.loc_);
    }
}

\"severity\" {
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    switch(driver.ctx_) {
    case ParserContext::LOGGERS:
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        return AgentParser::make_SEVERITY(driver.loc_);
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    default:
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        return AgentParser::make_STRING("severity", driver.loc_);
    }
}

\"Dhcp4\" {
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    switch(driver.ctx_) {
    case ParserContext::CONFIG:
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        return AgentParser::make_DHCP4(driver.loc_);
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    default:
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        return AgentParser::make_STRING("Dhcp4", driver.loc_);
    }
}

\"Dhcp6\" {
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    switch(driver.ctx_) {
    case ParserContext::CONFIG:
        return AgentParser::make_DHCP6(driver.loc_);
    default:
        return AgentParser::make_STRING("Dhcp6", driver.loc_);
    }
}

\"DhcpDdns\" {
    switch(driver.ctx_) {
    case ParserContext::CONFIG:
        return AgentParser::make_DHCPDDNS(driver.loc_);
    default:
        return AgentParser::make_STRING("DhcpDdns", driver.loc_);
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    }
}

{JSONString} {
    // A string has been matched. It contains the actual string and single quotes.
    // We need to get those quotes out of the way and just use its content, e.g.
    // for 'foo' we should get foo
    std::string raw(yytext+1);
    size_t len = raw.size() - 1;
    raw.resize(len);
    std::string decoded;
    decoded.reserve(len);
    for (size_t pos = 0; pos < len; ++pos) {
        int b = 0;
        char c = raw[pos];
        switch (c) {
        case '"':
            // impossible condition
            driver.error(driver.loc_, "Bad quote in \"" + raw + "\"");
        case '\\':
            ++pos;
            if (pos >= len) {
                // impossible condition
                driver.error(driver.loc_, "Overflow escape in \"" + raw + "\"");
            }
            c = raw[pos];
            switch (c) {
            case '"':
            case '\\':
            case '/':
                decoded.push_back(c);
                break;
            case 'b':
                decoded.push_back('\b');
                break;
            case 'f':
                decoded.push_back('\f');
                break;
            case 'n':
                decoded.push_back('\n');
                break;
            case 'r':
                decoded.push_back('\r');
                break;
            case 't':
                decoded.push_back('\t');
                break;
            case 'u':
                // support only \u0000 to \u00ff
                ++pos;
                if (pos + 4 > len) {
                    // impossible condition
                    driver.error(driver.loc_,
                                 "Overflow unicode escape in \"" + raw + "\"");
                }
                if ((raw[pos] != '0') || (raw[pos + 1] != '0')) {
                    driver.error(driver.loc_, "Unsupported unicode escape in \"" + raw + "\"");
                }
                pos += 2;
                c = raw[pos];
                if ((c >= '0') && (c <= '9')) {
                    b = (c - '0') << 4;
                } else if ((c >= 'A') && (c <= 'F')) {
                    b = (c - 'A' + 10) << 4;
                } else if ((c >= 'a') && (c <= 'f')) {
                    b = (c - 'a' + 10) << 4;
                } else {
                    // impossible condition
                    driver.error(driver.loc_, "Not hexadecimal in unicode escape in \"" + raw + "\"");
                }
                pos++;
                c = raw[pos];
                if ((c >= '0') && (c <= '9')) {
                    b |= c - '0';
                } else if ((c >= 'A') && (c <= 'F')) {
                    b |= c - 'A' + 10;
                } else if ((c >= 'a') && (c <= 'f')) {
                    b |= c - 'a' + 10;
                } else {
                    // impossible condition
                    driver.error(driver.loc_, "Not hexadecimal in unicode escape in \"" + raw + "\"");
                }
                decoded.push_back(static_cast<char>(b & 0xff));
                break;
            default:
                // impossible condition
                driver.error(driver.loc_, "Bad escape in \"" + raw + "\"");
            }
            break;
        default:
            if ((c >= 0) && (c < 0x20)) {
                // impossible condition
                driver.error(driver.loc_, "Invalid control in \"" + raw + "\"");
            }
            decoded.push_back(c);
        }
    }

    return AgentParser::make_STRING(decoded, driver.loc_);
}

\"{JSONStringCharacter}*{ControlCharacter}{ControlCharacterFill}*\" {
    // Bad string with a forbidden control character inside
    driver.error(driver.loc_, "Invalid control in " + std::string(yytext));
}

\"{JSONStringCharacter}*\\{BadJSONEscapeSequence}[^\x00-\x1f"]*\" {
    // Bad string with a bad escape inside
    driver.error(driver.loc_, "Bad escape in " + std::string(yytext));
}

\"{JSONStringCharacter}*\\\" {
    // Bad string with an open escape at the end
    driver.error(driver.loc_, "Overflow escape in " + std::string(yytext));
}

"["    { return AgentParser::make_LSQUARE_BRACKET(driver.loc_); }
"]"    { return AgentParser::make_RSQUARE_BRACKET(driver.loc_); }
"{"    { return AgentParser::make_LCURLY_BRACKET(driver.loc_); }
"}"    { return AgentParser::make_RCURLY_BRACKET(driver.loc_); }
","    { return AgentParser::make_COMMA(driver.loc_); }
":"    { return AgentParser::make_COLON(driver.loc_); }

{int} {
    // An integer was found.
    std::string tmp(yytext);
    int64_t integer = 0;
    try {
        // In substring we want to use negative values (e.g. -1).
        // In enterprise-id we need to use values up to 0xffffffff.
        // To cover both of those use cases, we need at least
        // int64_t.
        integer = boost::lexical_cast<int64_t>(tmp);
    } catch (const boost::bad_lexical_cast &) {
        driver.error(driver.loc_, "Failed to convert " + tmp + " to an integer.");
    }

    // The parser needs the string form as double conversion is no lossless
    return AgentParser::make_INTEGER(integer, driver.loc_);
}

[-+]?[0-9]*\.?[0-9]*([eE][-+]?[0-9]+)? {
    // A floating point was found.
    std::string tmp(yytext);
    double fp = 0.0;
    try {
        fp = boost::lexical_cast<double>(tmp);
    } catch (const boost::bad_lexical_cast &) {
        driver.error(driver.loc_, "Failed to convert " + tmp + " to a floating point.");
    }

    return AgentParser::make_FLOAT(fp, driver.loc_);
}

true|false {
    string tmp(yytext);
    return AgentParser::make_BOOLEAN(tmp == "true", driver.loc_);
}

null {
   return AgentParser::make_NULL_TYPE(driver.loc_);
}

(?i:true) driver.error (driver.loc_, "JSON true reserved keyword is lower case only");

(?i:false) driver.error (driver.loc_, "JSON false reserved keyword is lower case only");

(?i:null) driver.error (driver.loc_, "JSON null reserved keyword is lower case only");

<*>.   driver.error (driver.loc_, "Invalid character: " + std::string(yytext));

<<EOF>> {
    if (driver.states_.empty()) {
        return AgentParser::make_END(driver.loc_);
    }
    driver.loc_ = driver.locs_.back();
    driver.locs_.pop_back();
    driver.file_ = driver.files_.back();
    driver.files_.pop_back();
    if (driver.sfile_) {
        fclose(driver.sfile_);
        driver.sfile_ = 0;
    }
    if (!driver.sfiles_.empty()) {
        driver.sfile_ = driver.sfiles_.back();
        driver.sfiles_.pop_back();
    }
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    agent__delete_buffer(YY_CURRENT_BUFFER);
    agent__switch_to_buffer(driver.states_.back());
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    driver.states_.pop_back();

    BEGIN(DIR_EXIT);
}

%%

using namespace isc::dhcp;

void
ParserContext::scanStringBegin(const std::string& str, ParserType parser_type)
{
    start_token_flag = true;
    start_token_value = parser_type;

    file_ = "<string>";
    sfile_ = 0;
    loc_.initialize(&file_);
    yy_flex_debug = trace_scanning_;
    YY_BUFFER_STATE buffer;
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    buffer = agent__scan_bytes(str.c_str(), str.size());
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    if (!buffer) {
        fatal("cannot scan string");
        // fatal() throws an exception so this can't be reached
    }
}

void
ParserContext::scanFileBegin(FILE * f,
                              const std::string& filename,
                              ParserType parser_type)
{
    start_token_flag = true;
    start_token_value = parser_type;

    file_ = filename;
    sfile_ = f;
    loc_.initialize(&file_);
    yy_flex_debug = trace_scanning_;
    YY_BUFFER_STATE buffer;

    // See dhcp6_lexer.cc header for available definitions
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    buffer = agent__create_buffer(f, 65536 /*buffer size*/);
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    if (!buffer) {
        fatal("cannot scan file " + filename);
    }
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    agent__switch_to_buffer(buffer);
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}

void
ParserContext::scanEnd() {
    if (sfile_)
        fclose(sfile_);
    sfile_ = 0;
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    static_cast<void>(agent_lex_destroy());
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    // Close files
    while (!sfiles_.empty()) {
        FILE* f = sfiles_.back();
        if (f) {
            fclose(f);
        }
        sfiles_.pop_back();
    }
    // Delete states
    while (!states_.empty()) {
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        agent__delete_buffer(states_.back());
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        states_.pop_back();
    }
}

void
ParserContext::includeFile(const std::string& filename) {
    if (states_.size() > 10) {
        fatal("Too many nested include.");
    }

    FILE* f = fopen(filename.c_str(), "r");
    if (!f) {
        fatal("Can't open include file " + filename);
    }
    if (sfile_) {
        sfiles_.push_back(sfile_);
    }
    sfile_ = f;
    states_.push_back(YY_CURRENT_BUFFER);
    YY_BUFFER_STATE buffer;
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    buffer = agent__create_buffer(f, 65536 /*buffer size*/);
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    if (!buffer) {
        fatal( "Can't scan include file " + filename);
    }
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    agent__switch_to_buffer(buffer);
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    files_.push_back(file_);
    file_ = filename;
    locs_.push_back(loc_);
    loc_.initialize(&file_);

    BEGIN(INITIAL);
}

namespace {
/// To avoid unused function error
class Dummy {
    // cppcheck-suppress unusedPrivateFunction
    void dummy() { yy_fatal_error("Fix me: how to disable its definition?"); }
};
}