Re: [Boost-users] [spirit] Segmentation fault when parsing grammar with threads

6 Mar 2008


      In case you don't get an answer here you might try posting on the boost 
spirit general mailing list.

Jeff Flinn


Andreas Bruckmeier wrote:
...
Hi out there,
after searching for the cause of segmentation faults in my program 
i figured out that it happens while parsing my grammar with spirit.
But this happens only if i run multiple threads, 
with only one thread all works as expected.
I used the current boost trunk, gcc 4.1.2 and option D_REENTRANT
Does anybody have a clue what happens inside parse(...) 
that could cause this segfault?
Best regards
Andi
calling code: ('buf' is a zero-terminated string)
--------------------------------------------------------
HttpRequestGrammar parser;
parse_info<const char*> parserInfo = parse(buf, parser);
my grammar: (cutted some rules to limit length ;-))
--------------------------------------------------------
#ifndef BASIC_HTTP_GRAMMAR_H_
#define BASIC_HTTP_GRAMMAR_H_
#include <boost/spirit/core.hpp>
#include <boost/spirit/actor/assign_actor.hpp>
#include <boost/spirit/actor/insert_at_actor.hpp>
using namespace boost::spirit;
struct HttpRequestGrammar : public grammar<HttpRequestGrammar> {
template <typename ScannerT> struct definition {
definition(HttpRequestGrammar const& self) {
      first = (
request                = *( SP | CRLF ) >> requestLine >> CRLF 
                                 >> *(( generalHeader | requestHeader |
entityHeader ) >> CRLF) >> CRLF,
requestLine            = method[insert_at_a(self.headerMap,
"method")] >> SP 
                                 >> requestUri[insert_at_a(self.headerMap,
"url")] 
                                 >> SP >>
httpVersion[insert_at_a(self.headerMap, "version")],
method                 = str_p("GET") | "HEAD",
...
..
        token                  = +graph_p,
        SP                     = str_p(" "),
        CRLF                   = str_p("\r\n")
      );
    }
subrule<0> request;
    subrule<1> requestLine;
    subrule<2> generalHeader;
...
..
    subrule<1000> SP;
    subrule<1001> CRLF;
rule<ScannerT> first;
    rule<ScannerT> const&
start() const {
      return first;
    }
};
mutable std::map<std::string, std::string> headerMap; };
#endif /*BASIC_HTTP_GRAMMAR_H_*/