1 files changed, 122 insertions, 0 deletions
diff --git a/src/serial.c b/src/serial.c
new file mode 100644
index 0000000..0fd83fd
--- /dev/null
+++ b/src/serial.c
@@ -0,0 +1,122 @@
+#include <errno.h>
+#include <fcntl.h> /* O_RDWR */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <time.h>
+
+#define BUFFER_SIZE 256
+
+int openSerialPort(char pathToPort[]) {
+
+  static int serialPort;
+  struct termios serialTerminal;
+
+  serialPort = open(pathToPort, O_RDWR);
+  if (serialPort < 0) {
+    printf("Error open(): %s\n", strerror(errno));
+    return -1;
+  }
+
+  if (tcgetattr(serialPort, &serialTerminal) != 0) {
+    printf("Error tcgetattr(): %s\n", strerror(errno));
+    close(serialPort);
+    return -1;
+  }
+
+  serialTerminal.c_cflag |= CREAD;
+
+  /* serialTerminal.c_iflag &= ~(BRKINT | IGNBRK | INLCR | IGNCR | ICRNL | IXOFF
+     | IUTF8 | IUCLC | IXANY | IMAXBEL); */
+  serialTerminal.c_iflag &=
+      ~(IGNBRK | BRKINT | INLCR | IGNCR | ICRNL | IXON | IXOFF | IUCLC | IXANY |
+        IMAXBEL | IGNPAR | PARMRK | INPCK | ISTRIP);
+
+  /* serialTerminal.c_lflag &= ~(ECHO | ECHONL | NOFLSH | ISIG | TOSTOP | ICANON
+     | IEXTEN | ECHOE | ECHOK); */
+  serialTerminal.c_lflag &= ~(ICANON | ISIG | ECHO | ECHONL | ECHOE | ECHOK);
+
+  /* serialTerminal.c_oflag &=
+      ~(OLCUC | OCRNL | OPOST | OFILL | ONLCR | ONOCR | ONLRET | OFDEL); */
+  serialTerminal.c_oflag &= ~(OPOST);
+
+  serialTerminal.c_cc[VTIME] = 0;
+  serialTerminal.c_cc[VMIN] = 0;
+
+  cfsetispeed(&serialTerminal, B115200);
+  cfsetospeed(&serialTerminal, B115200);
+
+  if (tcsetattr(serialPort, TCSANOW, &serialTerminal) != 0) {
+    printf("Error tcsetattr(): %s\n", strerror(errno));
+    close(serialPort);
+    return -1;
+  }
+
+  return serialPort;
+}
+
+int querySerialPort(char **output, int serialPort, char *input) {
+
+  time_t timeStart;
+  unsigned long idx;
+  int bytesRead, bufferFree, returnCode, isEnd,
+      bufferSize = sizeof(char) * BUFFER_SIZE; /* initial size in bytes */
+  char *txBuffer, *buffer = calloc(BUFFER_SIZE, sizeof(char));
+  const char *responseCodes[8] = {"\r\nOK\r\n",    "\r\nCONNECT\r\n",
+                                  "\r\nRING\r\n",  "\r\nNO CARRIER\r\n",
+                                  "\r\nERROR\r\n", "\r\nNO DIALTONE\r\n",
+                                  "\r\nBUSY\r\n",  "\r\nNO ANSWER\r\n"};
+
+  txBuffer = malloc(sizeof(char) * (strlen(input) + 2));
+  strncpy(txBuffer, input, sizeof(char) * (strlen(input) + 1));
+  strncat(txBuffer, "\r", 2 * sizeof(char));
+  if (write(serialPort, txBuffer, sizeof(char) * (strlen(txBuffer))) < 0) {
+    printf("Error write(): %s\n", strerror(errno));
+    free(txBuffer);
+    free(buffer);
+    return 1;
+  }
+  free(txBuffer);
+
+  bytesRead = 0;
+  bufferFree = bufferSize;
+  returnCode = isEnd = 0;
+  timeStart = time(NULL);
+  while (!isEnd) {
+    bytesRead =
+        read(serialPort, buffer + bufferSize - bufferFree, bufferFree - 1);
+    if (bytesRead < 0) {
+      printf("Error reading serial port\n");
+      returnCode = 1;
+      break;
+    }
+
+    else if (bytesRead > 0) {
+      buffer[bytesRead] = '\0';
+      bufferFree -= (bytesRead + 1);
+
+      if (bufferFree == 0) {
+        bufferSize += bufferFree = BUFFER_SIZE;
+        buffer = realloc(buffer, bufferSize);
+      }
+
+      for (idx = 0; idx < sizeof(responseCodes) / sizeof(*responseCodes);
+           idx++) {
+        if (strstr(buffer, responseCodes[idx])) {
+          isEnd = 1;
+          break;
+        }
+      }
+    } else if (bytesRead == 0 && time(NULL) - timeStart > 180) {
+      printf("Response timeout after 180 seconds\n");
+      returnCode = 1;
+      break;
+    }
+  }
+
+  *output = realloc(*output, bufferSize);
+  strncpy(*output, buffer, bufferSize);
+  free(buffer);
+  return returnCode;
+}
+\ No newline at end of file