diff options
| -rw-r--r-- | rpc_serial.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/rpc_serial.c b/rpc_serial.c index 728bbd8..0e0e6ff 100644 --- a/rpc_serial.c +++ b/rpc_serial.c @@ -35,6 +35,7 @@ #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> +#include <sys/file.h> #include <netinet/in.h> #include <termios.h> #include <unistd.h> @@ -66,11 +67,17 @@ hal_error_t hal_serial_init(const char * const device, const uint32_t speed) struct termios tty; speed_t termios_speed; + /* + * Apparently Linux is too cool to need an atomic mechanism for + * locking an existing file, so we can't uses O_EXLOCK. Sigh. + */ + fd = open(device, O_RDWR | O_NOCTTY | O_SYNC); - if (fd == -1) { - fprintf(stderr, "open %s: ", device); - return perror(""), HAL_ERROR_RPC_TRANSPORT; - } + if (fd == -1) + return perror(device), HAL_ERROR_RPC_TRANSPORT; + + if (flock(fd, LOCK_EX) < 0) + return perror(device), HAL_ERROR_RPC_TRANSPORT; if (tcgetattr (fd, &tty) != 0) return perror("tcgetattr"), HAL_ERROR_RPC_TRANSPORT; |