First Version of IO

bsp_linux/hardware/hardware.c

@@ -46,7 +46,7 @@ int hw_device_open(const char *path, size_t path_len) {
 
   int serial_fd = serial_open(path, path_len);
 
-  if (serial_fd != -1) {
+  if (serial_fd >= -1) {
     return serial_fd;
   }
 
@@ -78,7 +78,7 @@ int hw_device_open(const char *path, size_t path_len) {
 
   for (current_candidate = addr_candidates; current_candidate != NULL;
        current_candidate = current_candidate->ai_next) {
-    sock = socket(current_candidate->ai_family, current_candidate->ai_socktype,
+    sock = socket(current_candidate->ai_family, current_candidate->ai_socktype | SOCK_NONBLOCK,
                   current_candidate->ai_protocol);
     if (sock == -1) {
       continue;

bsp_linux/hardware/serial.c

@@ -18,12 +18,13 @@ int convert_errno(int errno_value) {
   }
 }
 
-// returns fd if ok, converted errno if error
+// TODO: can we extend errno safely?
+// returns fd if ok, -1 on error 0 if no match
 int serial_open_actual(const char *path, speed_t speed) {
     // open serial
   int fd = open(path, O_RDWR | O_NOCTTY | O_SYNC);
   if (fd < 0) {
-    return convert_errno(errno);
+    return -1;
   }
 
   struct termios termios;
@@ -31,7 +32,7 @@ int serial_open_actual(const char *path, speed_t speed) {
   // initialize termios struct
   int ret = tcgetattr(fd, &termios);
   if (ret < 0) {
-    return convert_errno(errno);
+    return -1;
   }
 
   // configure for raw input
@@ -44,19 +45,19 @@ int serial_open_actual(const char *path, speed_t speed) {
   // set speed
   ret = cfsetspeed(&termios, speed);
   if (ret < 0) {
-    return convert_errno(errno);
+    return -1;
   }
 
   ret = tcsetattr(fd, TCSANOW, &termios);
   if (ret < 0) {
-    return convert_errno(errno);
+    return -1;
   }
 
   return fd;
 }
 
 
-// returns fd if success, -1 if no path match <-1 if error
+// returns fd if success, -1 on error, -2 if no match
 int serial_open(const char *path, size_t path_len) {
   if (compare_string_chars("ps/uart_mtg", path, path_len) == 1) {
     return serial_open_actual("/dev/ttyUSB0", B921600);
@@ -64,5 +65,5 @@ int serial_open(const char *path, size_t path_len) {
   if (compare_string_chars("debug/uart🚀", path, path_len) == 1) {
     return serial_open_actual("/dev/ttyUSB0", B115200);
   }
-  return -1;
+  return -2;
 }