Set raw TTY attributes on patty_kiss_tnc_new_fd()

Changes:

    * Use cfmakeraw() to set raw TTY attributes in KISS TNC constructor
      patty_kiss_tnc_new_fd()

    * Restore previous TTY attributes in patty_kiss_tnc_destroy()

examples/server.c

@@ -55,7 +55,6 @@ int main(int argc, char **argv) {
 
     if (isatty(info.fd) && grantpt(info.fd) == 0 && unlockpt(info.fd) == 0) {
         char name[256];
-        struct termios t;
 
         if (ptsname_r(info.fd, name, sizeof(name)) < 0) {
             fprintf(stderr, "%s: %s: %s: %s\n",
@@ -64,22 +63,6 @@ int main(int argc, char **argv) {
             goto error_open;
         }
 
-        if (tcgetattr(info.fd, &t) < 0) {
-            fprintf(stderr, "%s: %s: %s: %s\n",
-                argv[0], argv[1], "tcgetattr()", strerror(errno));
-
-            goto error_open;
-        }
-
-        cfmakeraw(&t);
-
-        if (tcsetattr(info.fd, TCSANOW, &t) < 0) {
-            fprintf(stderr, "%s: %s: %s: %s\n",
-                argv[0], argv[1], "tcsetattr()", strerror(errno));
-
-            goto error_open;
-        }
-
         fprintf(stderr, "pts %s\n", name);
     }
 

src/kiss.c

@@ -3,6 +3,7 @@
 #include <inttypes.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <termios.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
@@ -24,6 +25,9 @@ enum tnc_opts {
 };
 
 struct _patty_kiss_tnc {
+    struct termios attrs,
+                   attrs_old;
+
     int fd,
         opts;
 
@@ -48,6 +52,18 @@ patty_kiss_tnc *patty_kiss_tnc_new_fd(int fd) {
         goto error_malloc_buf;
     }
 
+    if (tcgetattr(fd, &tnc->attrs) < 0) {
+        goto error_tcgetattr;
+    }
+
+    memcpy(&tnc->attrs_old, &tnc->attrs, sizeof(tnc->attrs_old));
+
+    cfmakeraw(&tnc->attrs);
+
+    if (tcsetattr(fd, TCSANOW, &tnc->attrs) < 0) {
+        goto error_tcsetattr;
+    }
+
     tnc->fd      =  fd;
     tnc->opts    =  TNC_NONE;
     tnc->bufsz   =  PATTY_KISS_BUFSZ;
@@ -57,6 +73,8 @@ patty_kiss_tnc *patty_kiss_tnc_new_fd(int fd) {
 
     return tnc;
 
+error_tcsetattr:
+error_tcgetattr:
 error_malloc_buf:
     free(tnc);
 
@@ -123,6 +141,8 @@ int patty_kiss_tnc_fd(patty_kiss_tnc *tnc) {
 }
 
 void patty_kiss_tnc_destroy(patty_kiss_tnc *tnc) {
+    (void)tcsetattr(tnc->fd, TCSANOW, &tnc->attrs_old);
+
     if (tnc->opts & TNC_CLOSE_ON_DESTROY) {
         close(tnc->fd);
     }