[patch] ax25-tools-kissattach-pty.diff: Adds symlinking support to kissattach

ax25-tools-kissattach-pty.diff (text/plain), 5.10 KB, created by Stuart Longland on 2014-03-29 12:27:34 UTC

--- kiss/kissattach.c.orig	2014-01-11 10:11:52.043000000 +1000
+++ kiss/kissattach.c	2014-01-11 13:18:42.488000000 +1000
@@ -18,6 +18,9 @@
 #include <sys/socket.h>
 #include <sys/ioctl.h>
 
+#include <pwd.h>
+#include <grp.h>
+
 #include <net/if.h>
 #include <netax25/ax25.h>
 #include <netrose/rose.h>
@@ -32,6 +35,8 @@
 #define N_6PACK 7	/* This is valid for all architectures in 2.2.x */
 #endif
 
+#define PTMX_TTY	"/dev/ptmx"
+
 static char *callsign;
 static int  speed	= 0;
 static int  mtu		= 0;
@@ -42,6 +47,7 @@
 static char *inetaddr	= NULL;
 static int allow_broadcast = 0;
 static int i_am_unix98_pty_master = 0; /* unix98 ptmx support */
+static int symlink_pty = 0;
 
 static char *kiss_basename(char *s)
 {
@@ -58,6 +64,8 @@
 
 	if (!i_am_unix98_pty_master)
 		tty_unlock(kttyname);
+	else if (symlink_pty)
+		unlink(kttyname);
 
 	exit(0);
 }
@@ -214,7 +222,8 @@
 
 static void usage(void)
 {
-        fprintf(stderr, "usage: %s [-b] [-l] [-m mtu] [-v] tty port [inetaddr]\n", progname);
+        fprintf(stderr, "usage: %s [-b] [-l] [-m mtu] [-v] [-o user:group] [-p mode] tty port [inetaddr]\n",
+			progname);
 }
 
 int main(int argc, char *argv[])
@@ -227,12 +236,18 @@
 	                        * the client has to use */
 	struct hostent *hp = NULL;
 
+	/* Name of the user and group who will "own" the pty */
+	char* pty_owner_user = NULL;
+	char* pty_owner_group = NULL;
+	/* Mode for pty: if 0; use defaults */
+	mode_t pty_mode = 0;
+
 	progname = kiss_basename(argv[0]);
 
 	if (!strcmp(progname, "spattach"))
 		disc = N_6PACK;
 
-	while ((fd = getopt(argc, argv, "b6i:lm:v")) != -1) {
+	while ((fd = getopt(argc, argv, "b6i:lm:o:p:v")) != -1) {
 		switch (fd) {
 			case '6':
 				disc = N_6PACK;
@@ -253,6 +268,24 @@
 					return 1;
 				}
 				break;
+			case 'o':
+				/* Change the owner of the pty */
+				{
+					char* colon = index(optarg,':');
+					if (colon) {
+						pty_owner_user = optarg;
+						pty_owner_group = colon + 1;
+						*colon = 0;
+					} else {
+						fprintf(stderr, "%s: Must specify user:group\n", progname);
+						return 1;
+					}
+				}
+				break;
+			case 'p':
+				/* Change the permissions (mode) of the pty */
+				pty_mode = (mode_t)strtoul(optarg, NULL, 8);
+				break;
 			case 'v':
 				printf("%s: %s\n", progname, VERSION);
 				return 0;
@@ -278,8 +311,17 @@
 	if (argc-1 >= optind && !inetaddr)
 		inetaddr = argv[optind];
 
-	if (!strcmp("/dev/ptmx", kttyname))
+	if (!strcmp(PTMX_TTY, kttyname)) {
+		i_am_unix98_pty_master = 1;
+	} else if (strstr(kttyname, "pty:") == kttyname) {
+		/*
+		 * If the path starts with pty:, then create a
+		 * new pty (Unix98 style) and make a symlink to it
+		 */
 		i_am_unix98_pty_master = 1;
+		kttyname = index(kttyname, ':') + 1;
+		symlink_pty = 1;
+	}
 
 	if (!i_am_unix98_pty_master) {
 		if (tty_is_locked(kttyname)) {
@@ -296,7 +338,7 @@
 		return 1;
 	}
 
-	if ((fd = open(kttyname, O_RDONLY | O_NONBLOCK)) == -1) {
+	if ((fd = open((symlink_pty ? PTMX_TTY : kttyname), O_RDONLY | O_NONBLOCK)) == -1) {
 		if (errno == ENOENT) {
 			fprintf(stderr, "%s: Cannot find serial device %s, no such file or directory.\n", progname, kttyname);
 		} else {
@@ -353,12 +395,69 @@
 
 	printf("AX.25 port %s bound to device %s\n", portname, dev);
 	if (i_am_unix98_pty_master) {
-		/* Users await the slave pty to be referenced in the 3d line */
-		printf("Awaiting client connects on\n%s\n", namepts);
+		/* Are we being asked to chown? */
+		if (pty_owner_user) {
+			/* Look up the user */
+			struct passwd user;
+			struct passwd* user_ptr = NULL;
+			struct group grp;
+			struct group* grp_ptr = NULL;
+			char buffer[512];
+			int err = getpwnam_r(pty_owner_user, &user,
+				buffer, sizeof(buffer)-1, &user_ptr);
+			if (err) {
+				fprintf(stderr,
+					"Failed to look up user: %s (%d)\n",
+					strerror(err), err);
+				return 1;
+			}
+
+			err = getgrnam_r(pty_owner_group, &grp,
+				buffer, sizeof(buffer)-1, &grp_ptr);
+			if (err) {
+				fprintf(stderr,
+					"Failed to look up group: %s (%d)\n",
+					strerror(err), err);
+				return 1;
+			}
+
+			if (user_ptr && grp_ptr &&
+					chown(namepts, user_ptr->pw_uid,
+						grp_ptr->gr_gid)) {
+				fprintf(stderr,
+					"Failed to change ownership: %s (%d)\n",
+					strerror(errno), errno);
+				return 1;
+			}
+		}
+
+		/* Are we being asked to chmod? */
+		if (pty_mode) {
+			if (chmod(namepts, pty_mode)) {
+				fprintf(stderr,
+					"Failed to change mode: %s (%d)\n",
+					strerror(errno), errno);
+			}
+		}
+
+		if (symlink_pty) {
+			/* Create the symlink */
+			if (symlink(namepts, kttyname)) {
+				fprintf(stderr,
+					"Failed to symlink PTY %s to %s: %s (%d)\n",
+					kttyname, namepts, strerror(errno), errno);
+				return 1;
+			}
+		} else {
+			/* Users await the slave pty to be referenced in the 3d line */
+			printf("Awaiting client connects on\n%s\n", namepts);
+		}
 	}
 	if (logging) {
 		openlog(progname, LOG_PID, LOG_DAEMON);
 		syslog(LOG_INFO, "AX.25 port %s bound to device %s%s%s\n", portname, dev, (i_am_unix98_pty_master ? " with slave pty " : ""), (i_am_unix98_pty_master ? namepts : ""));
+		if (symlink_pty)
+			syslog(LOG_INFO, "Slave pty %s is symlinked to %s.", namepts, kttyname);
 
 	}