Hi
I posted on this a couple of hours ago with some problems. It turned
out that some of the problems I had might have been due to buggy
hardware.
But there is still some thing I do not understand...
So, now I have reproduced some of of the problems I have with out any
hardware (except from a PC).
Basically I'm trying to read from a input source (in this case stdin)
with a timeout. Due to the design of the existing application where
this have to fit is it not possible to call run on my io_service.
Here is my try so far:
#include
#include
#include
using namespace std;
void set_result( boost::optionalboost::system::error_code * a,
boost::system::error_code b ) {
if( b == 0)
a->reset( b );
}
void receive(boost::asio::io_service & io,
boost::asio::posix::stream_descriptor & stream, boost::asio::streambuf
& result){
boost::optionalboost::system::error_code timer_result;
boost::optionalboost::system::error_code read_result;
boost::asio::deadline_timer timer( io );
timer.expires_from_now( boost::posix_time::milliseconds(5000) );
// allow up to 50ms of timeout for every char
timer.async_wait( boost::bind(&set_result, &timer_result, _1) );
boost::asio::async_read(
stream,
result,
boost::asio::transfer_at_least(1),
boost::bind( &set_result, &read_result, _1 ));
boost::system::error_code ec;
while(1) {
io.reset();
io.poll_one(ec);
if ( read_result ) {
timer.cancel();
return;
} else if ( timer_result )
throw std::runtime_error("timeout");
}
}
void receive(boost::asio::io_service & io,
boost::asio::posix::stream_descriptor & stream, size_t size,
boost::asio::streambuf & result){
while( result.size() < size )
receive(io, stream, result);
}
int main(int argc, const char *argv[])
{
boost::asio::io_service io;
boost::asio::posix::stream_descriptor in(io, ::dup(STDIN_FILENO));
for(int i = 0; i < 5; i++){
std::cout << i << " Type in 4 chareters and press enter" <<
std::endl << std::endl;
std::cout << "in> ";
std::cout.flush();
try {
boost::asio::streambuf buf;
receive(io, in, 5, buf);
std::cout << "out> ";
std::copy(boost::asio::buffer_cast(buf.data()), boost::asio::buffer_cast(buf.data()) +
buf.size(), ostream_iterator<char>(std::cout));
} catch (const std::exception & e) {
std::cout << e.what() << endl;
}
}
return 0;
}
At my first look, I thought that it was working, but after playing
more around with the test app, I got some segmentations faults.
I found that something bad happens if I wait for the first query to
timeout, and then enter 5 chars the next.
Here is what valgrind says:
==17848== Memcheck, a memory error detector
==17848== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==17848== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info
==17848== Command: ./ccTalkScan
==17848==
==17848==
0 Type in 4 chareters and press enter
in> ==17848== Invalid read of size 8
==17848== at 0x546EB4A: ??? (setcontext.S:60)
==17848== by 0x425847: receive(boost::asio::io_service&,
boost::asio::posix::basic_stream_descriptorboost::asio::posix::stream_descriptor_service&,
unsigned long, boost::asio::basic_streambuf&)
(ccTalkScan.cxx:3
20)
==17848== by 0x425982: main (ccTalkScan.cxx:334)
==17848== Address 0x7feffdf68 is not stack'd, malloc'd or (recently) free'd
==17848==
==17848== Invalid read of size 8
==17848== at 0x546EB52: ??? (setcontext.S:63)
==17848== by 0x425847: receive(boost::asio::io_service&,
boost::asio::posix::basic_stream_descriptorboost::asio::posix::stream_descriptor_service&,
unsigned long, boost::asio::basic_streambuf&)
(ccTalkScan.cxx:3
20)
==17848== by 0x425982: main (ccTalkScan.cxx:334)
==17848== Address 0x7feffdf58 is not stack'd, malloc'd or (recently) free'd
==17848==
==17848== Invalid read of size 8
==17848== at 0x546EB59: ??? (setcontext.S:64)
==17848== by 0x425847: receive(boost::asio::io_service&,
boost::asio::posix::basic_stream_descriptorboost::asio::posix::stream_descriptor_service&,
unsigned long, boost::asio::basic_streambuf&)
(ccTalkScan.cxx:320)
==17848== by 0x425982: main (ccTalkScan.cxx:334)
==17848== Address 0x7feffdf28 is not stack'd, malloc'd or (recently) free'd
==17848==
==17848== Invalid read of size 8
==17848== at 0x546EB4A: ??? (setcontext.S:60)
==17848== by 0x5E4BD2C: (below main) (in /lib64/libc-2.12.2.so)
==17848== Address 0x7feffdfd8 is not stack'd, malloc'd or (recently) free'd
==17848==
==17848== Invalid read of size 8
==17848== at 0x546EB52: ??? (setcontext.S:63)
==17848== by 0x5E4BD2C: (below main) (in /lib64/libc-2.12.2.so)
==17848== Address 0x7feffdfc8 is not stack'd, malloc'd or (recently) free'd
==17848==
==17848== Invalid read of size 8
==17848== at 0x546EB59: ??? (setcontext.S:64)
==17848== by 0x5E4BD2C: (below main) (in /lib64/libc-2.12.2.so)
==17848== Address 0x7feffdf98 is not stack'd, malloc'd or (recently) free'd
==17848==
timeout
1 Type in 4 chareters and press enter
in> asdf
==17848== Syscall param readv(vector[...]) points to unaddressable byte(s)
==17848== at 0x5EF7A81: readv (in /lib64/libc-2.12.2.so)
==17848== by 0x42AF1C:
boost::asio::detail::descriptor_ops::non_blocking_read(int, iovec*,
unsigned long, boost::system::error_code&, unsigned long&)
(descriptor_ops.ipp:153)
==17848== by 0x4360BF:
boost::asio::detail::descriptor_read_op_baseboost::asio::mutable_buffers_1::do_perform(boost::asio::detail::reactor_op*)
(descriptor_read_op.hpp:55)
==17848== by 0x427CE4: boost::asio::detail::reactor_op::perform()
(reactor_op.hpp:40)
==17848== by 0x429003:
boost::asio::detail::epoll_reactor::run(bool,
boost::asio::detail::op_queueboost::asio::detail::task_io_service_operation&)
(epoll_reactor.ipp:286)
==17848== by 0x429C81:
boost::asio::detail::task_io_service::do_one(boost::asio::detail::scoped_lockboost::asio::detail::posix_mutex&,
boost::asio::detail::task_io_service::idle_thread_info*)
(task_io_service.ipp:264)
==17848== by 0x42986F:
boost::asio::detail::task_io_service::poll_one(boost::system::error_code&)
(task_io_service.ipp:188)
==17848== by 0x42A0C2:
boost::asio::io_service::poll_one(boost::system::error_code&)
(io_service.ipp:103)
==17848== by 0x4255E1: receive(boost::asio::io_service&,
boost::asio::posix::basic_stream_descriptorboost::asio::posix::stream_descriptor_service&,
boost::asio::basic_streambuf&)
(ccTalkScan.cxx:307)
==17848== by 0x425847: receive(boost::asio::io_service&,
boost::asio::posix::basic_stream_descriptorboost::asio::posix::stream_descriptor_service&,
unsigned long, boost::asio::basic_streambuf&)
(ccTalkScan.cxx:320)
==17848== by 0x425982: main (ccTalkScan.cxx:334)
==17848== Address 0x65ba4f0 is 0 bytes inside a block of size 512 free'd
==17848== at 0x4C25C4F: operator delete(void*) (vg_replace_malloc.c:387)
==17848== by 0x432D07:
__gnu_cxx::new_allocator<char>::deallocate(char*, unsigned long)
(new_allocator.h:95)
==17848== by 0x4316BF: std::_Vector_base
::_M_deallocate(char*, unsigned long) (stl_vector.h:146)
==17848== by 0x42FD64: std::_Vector_base 2 Type in 4 chareters and press enter
in> timeout
3 Type in 4 chareters and press enter
in> timeout
4 Type in 4 chareters and press enter
in> timeout
==17848==
==17848== HEAP SUMMARY:
==17848== in use at exit: 168 bytes in 3 blocks
==17848== total heap usage: 65 allocs, 62 frees, 22,246 bytes allocated
==17848==
==17848== LEAK SUMMARY:
==17848== definitely lost: 0 bytes in 0 blocks
==17848== indirectly lost: 0 bytes in 0 blocks
==17848== possibly lost: 0 bytes in 0 blocks
==17848== still reachable: 168 bytes in 3 blocks
==17848== suppressed: 0 bytes in 0 blocks
==17848== Rerun with --leak-check=full to see details of leaked memory
==17848==
==17848== For counts of detected and suppressed errors, rerun with: -v
==17848== Use --track-origins=yes to see where uninitialised values come from
==17848== ERROR SUMMARY: 27 errors from 9 contexts (suppressed: 4 from 4)
I have tried different things to fix, but I that I might have mis
understood a thing or two here. So some help would be most
appreciated.
--
Allan W. Nielsen
