mch/SerialControl.cc

   1 #include "SerialControl.h"
   2
   3 namespace remote { namespace mch {
   4
   5 SerialControl::SerialControl()
   6         : port(-1), childPid(-1)
   7 {
   8 }
   9
  10 SerialControl::~SerialControl()
  11 {
  12         endChild(true);
  13         if (isOpen())
  14                 closeTty();
  15 }
  16
  17 bool SerialControl::openTty(const std::string platform, const std::string tty)
  18 {
  19         struct termios newsertio;
  20
  21         if (isOpen()) {
  22                 Log::debug("TTY already open for %s", tty.c_str());
  23                 return false;
  24         }
  25
  26         Log::info("Opening TTY %s", tty.c_str());
  27         port = open(tty.c_str(), O_RDWR | O_NOCTTY | O_NONBLOCK);
  28         if (port == -1) {
  29                 Log::error("Failed to open %s: %s", tty.c_str(), strerror(errno));
  30                 return false;
  31         }
  32
  33         tcgetattr(port, &oldsertio); /* save current port settings */
  34
  35         /*
  36          * 8 data, no parity, 1 stop bit. Ignore modem control lines. Enable
  37          * receive. NO HARDWARE FLOW CONTROL!
  38          */
  39         newsertio.c_cflag = CS8 | CLOCAL | CREAD;
  40
  41         /* Set baud rate. */
  42         if (platform == "dig528-2")
  43                 newsertio.c_cflag |= B38400;
  44         else if(platform == "TMoteSky")
  45                 newsertio.c_cflag = B115200;
  46         else if (platform == "MicaZ")
  47                 newsertio.c_cflag = B57600;
  48         else
  49                 Log::error("Unknown platform '%s'", platform.c_str());
  50
  51         /* Raw input. Ignore errors and breaks. */
  52         newsertio.c_iflag = IGNBRK | IGNPAR;
  53
  54         /* Raw output. */
  55         newsertio.c_oflag = 0;
  56
  57         /* No echo and no signals. */
  58         newsertio.c_lflag = 0;
  59
  60         /* blocking read until 1 char arrives */
  61         newsertio.c_cc[VMIN]=1;
  62         newsertio.c_cc[VTIME]=0;
  63
  64         /* now clean the modem line and activate the settings for modem */
  65         tcflush(port, TCIFLUSH);
  66         tcsetattr(port, TCSANOW, &newsertio);
  67
  68         return true;
  69 }
  70
  71 void SerialControl::closeTty()
  72 {
  73         if (!isOpen())
  74                 return;
  75
  76         tcsetattr(port, TCSANOW, &oldsertio);
  77         close(port);
  78         port = -1;
  79 }
  80
  81 bool SerialControl::runChild(char * const args[], char * const envp[])
  82 {
  83         int pfd[2];
  84
  85         if (pipe(pfd) < 0)
  86                 return false;
  87         closeTty();
  88
  89         if ((childPid = fork())) {
  90                 /* Only use the reader end if we forked. */
  91                 if (hasChild())
  92                         port = pfd[0];
  93                 else
  94                         close(pfd[0]);
  95                 close(pfd[1]);
  96
  97         } else {
  98                 /* Redirect all standard output to the parent's pipe. */
  99                 if (dup2(pfd[1], STDOUT_FILENO) != -1 &&
 100                     dup2(pfd[1], STDERR_FILENO) != -1) {
 101                         close(pfd[0]);
 102                         close(pfd[1]);
 103                         execve(args[0], args, envp);
 104                 }
 105                 /* XXX: Make the failed child exit immediately. */
 106                 _exit(EXIT_FAILURE);
 107         }
 108
 109         return hasChild();
 110 }
 111
 112 bool SerialControl::endChild(bool killChild)
 113 {
 114         int status;
 115
 116         if (!hasChild())
 117                 return false;
 118
 119         if (killChild)
 120                 kill(childPid, SIGKILL);
 121
 122         waitpid(childPid, &status, 0);
 123         close(port);
 124         port = childPid = -1;
 125
 126         return killChild || (WIFEXITED(status) && WEXITSTATUS(status) == 0);
 127 }
 128
 129 bool SerialControl::controlDTR(bool enable)
 130 {
 131         int tmp = TIOCM_DTR;
 132         int req = enable ? TIOCMBIS : TIOCMBIC;
 133
 134         return ioctl(port, req, &tmp) != -1;
 135 }
 136
 137 ssize_t SerialControl::readBuf(char *buf, size_t len)
 138 {
 139         ssize_t res = read(port, buf, len);
 140
 141         if (res <= 0 && !hasChild())
 142                 closeTty();
 143
 144         return res;
 145 }
 146
 147 ssize_t SerialControl::writeBuf(const char* buf, size_t len)
 148 {
 149         return write(port, buf, len);
 150 }
 151
 152 bool SerialControl::hasChild()
 153 {
 154         return childPid != -1;
 155 }
 156
 157 bool SerialControl::isOpen()
 158 {
 159         return port != -1 && !hasChild();
 160 }
 161
 162 int SerialControl::getFd()
 163 {
 164         return port;
 165 }
 166
 167 }}