Re: [Patch] can-utils/slcanpty.c pseudo-terminal interface

[uescher <linux-can_ger.kernel.org@myvdr.de>]

Next try :)
Add Support for the Unix 98 pseudo-terminal interface /dev/ptmx /dev/pts/N
http://www.kernel.org/doc/man-pages/online/pages/man4/pts.4.html
My change is like this change:
http://sourceforge.net/tracker/index.php?func=detail&aid=3467521&group_id=146269&atid=764681
most Linux distributions do not configure their kernels to use the BSD 
pseudo-terminal interface (/dev/pty* and /dev/tty*) anymore; they uses 
the Unix 98 pseudo-terminal interface instead (/dev/ptmx and /dev/pts/*).
Maybe is it possible to add this patch for the next release.
Thanks.

Signed-off-by: Ulrich Escher<git@myvdr.de>
---
  slcanpty.c |   27 +++++++++++++++++++++++++++
  1 file changed, 27 insertions(+)

diff --git a/slcanpty.c b/slcanpty.c
index 67a7491..13ed96c 100644
--- a/slcanpty.c
+++ b/slcanpty.c
@@ -22,6 +22,9 @@
   *
   */

+/* To get ptsname grantpt and unlockpt definitions from stdlib.h */
+#define _GNU_SOURCE
+
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
@@ -40,6 +43,7 @@

  /* maximum rx buffer len: extended CAN frame with timestamp */
  #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
+#define DEVICE_NAME_PTMX "/dev/ptmx"

  #define DEBUG

@@ -383,6 +387,8 @@ int main(int argc, char **argv)
          fprintf(stderr, "Usage: %s <pty> <can interface>\n", argv[0]);
          fprintf(stderr, "e.g. '%s /dev/ptyc0 can0' creates"
              " /dev/ttyc0 for the slcan application\n", argv[0]);
+        fprintf(stderr, "e.g. for pseudo-terminal '%s %s can0' creates"
+            " /dev/pts/N\n", argv[0], DEVICE_NAME_PTMX);
          fprintf(stderr, "\n");
          return 1;
      }
@@ -404,6 +410,27 @@ int main(int argc, char **argv)
                 ECHONL | ECHOPRT | ECHOKE | ICRNL);
      tcsetattr(p, TCSANOW, &topts);

+    /* Support for the Unix 98 pseudo-terminal interface /dev/ptmx 
/dev/pts/N */
+    if  (strcmp(argv[1], DEVICE_NAME_PTMX) == 0) {
+        if (grantpt(p) < 0) {
+            perror("grantpt");
+            return 1;
+        }
+
+        if (unlockpt(p) < 0) {
+            perror("unlockpt");
+            return 1;
+        }
+
+        char *name_pts = NULL;    /* slave pseudo-terminal device name */
+        name_pts = ptsname(p);
+        if (name_pts == NULL) {
+            perror("ptsname");
+            return 1;
+        }
+        printf("open: %s: slave pseudo-terminal is %s\n", argv[1], 
name_pts);
+    }
+
      /* open socket */
      s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
      if (s < 0) {
--