HCIComm.cpp

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/*
 * Author: Sven Gothel <sgothel@jausoft.com>
 * Copyright (c) 2020 Gothel Software e.K.
 * Copyright (c) 2020 ZAFENA AB
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
#include <cstring>
#include <string>
#include <memory>
#include <cstdint>
#include <vector>
#include <cstdio>
 
#include <algorithm>
#include <type_traits>
 
// #define PERF_PRINT_ON 1
#include <jau/debug.hpp>
 
#include "HCIComm.hpp"
 
extern "C" {
    #include <inttypes.h>
    #include <unistd.h>
    #include <sys/param.h>
    #include <sys/uio.h>
    #include <sys/types.h>
    #include <sys/ioctl.h>
    #include <sys/socket.h>
    #include <poll.h>
}
 
namespace direct_bt {
 
int HCIComm::hci_open_dev(const uint16_t dev_id, const uint16_t channel) noexcept
{
    static_assert( sizeof(struct sockaddr) > sizeof(sockaddr_hci), "Requirement sizeof(struct sockaddr) > sizeof(sockaddr_hci)" );
    sockaddr addr_holder; // sizeof(struct sockaddr) > sizeof(sockaddr_hci), silent valgrind.
    sockaddr_hci * ptr_hci_addr = (sockaddr_hci*)&addr_holder;
    int fd, err;
 
    /**
     * dev_id is unsigned and hence always >= 0
    if ( 0 > dev_id ) {
        errno = ENODEV;
        ERR_PRINT("hci_open_dev: invalid dev_id");
        return -1;
    } */
 
    // Create a loose HCI socket
    fd = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);
    if (0 > fd ) {
        ERR_PRINT("HCIComm::hci_open_dev: socket failed");
        return fd;
    }
 
    // Bind socket to the HCI device
    bzero(&addr_holder, sizeof(addr_holder));
    ptr_hci_addr->hci_family = AF_BLUETOOTH;
    ptr_hci_addr->hci_dev = dev_id;
    ptr_hci_addr->hci_channel = channel;
    if (bind(fd, &addr_holder, sizeof(sockaddr_hci)) < 0) {
        ERR_PRINT("hci_open_dev: bind failed");
        goto failed;
    }
 
    return fd;
 
failed:
    err = errno;
    ::close(fd);
    errno = err;
 
    return -1;
}
 
int HCIComm::hci_close_dev(int dd) noexcept
{
    return ::close(dd);
}
 
// *************************************************
// *************************************************
// *************************************************
 
HCIComm::HCIComm(const uint16_t _dev_id, const uint16_t _channel) noexcept
: dev_id( _dev_id ), channel( _channel ),
  socket_descriptor( hci_open_dev(_dev_id, _channel) ), interrupt_flag(false), tid_read(0)
{
}
 
void HCIComm::close() noexcept {
    const std::lock_guard<std::recursive_mutex> lock(mtx_write); // RAII-style acquire and relinquish via destructor
    if( 0 > socket_descriptor ) {
        DBG_PRINT("HCIComm::close: Not opened: dd %d", socket_descriptor.load());
        return;
    }
    DBG_PRINT("HCIComm::close: Start: dd %d", socket_descriptor.load());
    PERF_TS_T0();
    // interrupt ::read(..) and , avoiding prolonged hang
    interrupt_flag = true;
    {
        pthread_t _tid_read = tid_read;
        tid_read = 0;
        if( 0 != _tid_read ) {
            pthread_t tid_self = pthread_self();
            if( tid_self != _tid_read ) {
                int kerr;
                if( 0 != ( kerr = pthread_kill(_tid_read, SIGALRM) ) ) {
                    ERR_PRINT("HCIComm::close: pthread_kill read %p FAILED: %d", (void*)_tid_read, kerr);
                }
            }
        }
    }
    hci_close_dev(socket_descriptor);
    socket_descriptor = -1;
    interrupt_flag = false;
    PERF_TS_TD("HCIComm::close");
    DBG_PRINT("HCIComm::close: End: dd %d", socket_descriptor.load());
}
 
jau::snsize_t HCIComm::read(uint8_t* buffer, const jau::nsize_t capacity, const int32_t timeoutMS) noexcept {
    jau::snsize_t len = 0;
    if( 0 > socket_descriptor ) {
        goto errout;
    }
    if( 0 == capacity ) {
        goto done;
    }
 
    if( timeoutMS ) {
        struct pollfd p;
        int n;
 
        p.fd = socket_descriptor; p.events = POLLIN;
        while ( !interrupt_flag && (n = poll(&p, 1, timeoutMS)) < 0 ) {
            if ( !interrupt_flag && ( errno == EAGAIN || errno == EINTR ) ) {
                // cont temp unavail or interruption
                continue;
            }
            goto errout;
        }
        if (!n) {
            errno = ETIMEDOUT;
            goto errout;
        }
    }
 
    while ((len = ::read(socket_descriptor, buffer, capacity)) < 0) {
        if (errno == EAGAIN || errno == EINTR ) {
            // cont temp unavail or interruption
            continue;
        }
        goto errout;
    }
 
done:
    return len;
 
errout:
    return -1;
}
 
jau::snsize_t HCIComm::write(const uint8_t* buffer, const jau::nsize_t size) noexcept {
    const std::lock_guard<std::recursive_mutex> lock(mtx_write); // RAII-style acquire and relinquish via destructor
    jau::snsize_t len = 0;
    if( 0 > socket_descriptor ) {
        goto errout;
    }
    if( 0 == size ) {
        goto done;
    }
 
    while( ( len = ::write(socket_descriptor, buffer, size) ) < 0 ) {
        if( EAGAIN == errno || EINTR == errno ) {
            continue;
        }
        goto errout;
    }
 
done:
    return len;
 
errout:
    return -1;
}
 
} /* namespace direct_bt */