support n̲o̲t̲ fork(2)ing for -T (by prepending the tty with ‘!’); especially useful on Linux since our own setsid(2) is more annoying; gets rid of the need for oneit_lite and similar hacks; WARNING: also removes chown/chmod on the tty!

main.c

@@ -34,7 +34,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.265 2013/06/02 03:09:16 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.266 2013/06/03 22:28:04 tg Exp $");
 
 extern char **environ;
 
@@ -48,6 +48,7 @@ extern char **environ;
 
 static uint8_t isuc(const char *);
 static int main_init(int, const char *[], Source **, struct block **);
+uint32_t chvt_rndsetup(const void *, size_t);
 void chvt_reinit(void);
 static void reclaim(void);
 static void remove_temps(struct temp *);
@@ -137,15 +138,25 @@ rndsetup(void)
 	/* introduce variation (and yes, second arg MBZ for portability) */
 	mksh_TIME(bufptr->tv);
 
+	h = chvt_rndsetup(bufptr, sizeof(*bufptr));
+
+	afree(cp, APERM);
+	return ((mksh_uari_t)h);
+}
+
+uint32_t
+chvt_rndsetup(const void *bp, size_t sz)
+{
+	register uint32_t h;
+
 	NZATInit(h);
 	/* variation through pid, ppid, and the works */
 	NZATUpdateMem(h, &rndsetupstate, sizeof(rndsetupstate));
 	/* some variation, some possibly entropy, depending on OE */
-	NZATUpdateMem(h, bufptr, sizeof(*bufptr));
+	NZATUpdateMem(h, bp, sz);
 	NZAATFinish(h);
 
-	afree(cp, APERM);
+	return (h);
-	return ((mksh_uari_t)h);
 }
 
 void

misc.c

@@ -30,7 +30,7 @@
 #include <grp.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.211 2013/05/02 20:21:44 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.212 2013/06/03 22:28:05 tg Exp $");
 
 #define KSH_CHVT_FLAG
 #ifdef MKSH_SMALL
@@ -54,7 +54,7 @@ static int do_gmatch(const unsigned char *, const unsigned char *,
     const unsigned char *, const unsigned char *);
 static const unsigned char *cclass(const unsigned char *, unsigned char);
 #ifdef KSH_CHVT_CODE
-static void chvt(const char *);
+static void chvt(const Getopt *);
 #endif
 
 /*XXX this should go away */
@@ -414,7 +414,7 @@ parse_args(const char **argv,
 			errorf("no TIOCSCTTY ioctl");
 #else
 			change_flag(FTALKING, OF_CMDLINE, true);
-			chvt(go.optarg);
+			chvt(&go);
 			break;
 #endif
 #endif
@@ -1925,48 +1925,57 @@ c_cd(const char **wp)
 
 
 #ifdef KSH_CHVT_CODE
+extern uint32_t chvt_rndsetup(const void *, size_t);
 extern void chvt_reinit(void);
 
 static void
-chvt(const char *fn)
+chvt(const Getopt *go)
 {
-	char dv[20];
+	const char *dv = go->optarg;
-	struct stat sb;
+	char *cp = NULL;
 	int fd;
 
-	if (*fn == '-') {
+	switch (*dv) {
-		memcpy(dv, "-/dev/null", sizeof("-/dev/null"));
+	case '-':
-		fn = dv + 1;
+		dv = "/dev/null";
-	} else {
+		break;
-		if (stat(fn, &sb)) {
+	case '!':
-			memcpy(dv, "/dev/ttyC", 9);
+		++dv;
-			strlcpy(dv + 9, fn, sizeof(dv) - 9);
+		/* FALLTHROUGH */
+	default: {
+		struct stat sb;
+
 		if (stat(dv, &sb)) {
-				strlcpy(dv + 8, fn, sizeof(dv) - 8);
+			cp = shf_smprintf("/dev/ttyC%s", dv);
-				if (stat(dv, &sb))
+			dv = cp;
-					errorf("%s: %s %s", "chvt",
+			if (stat(dv, &sb)) {
-					    "can't find tty", fn);
+				memmove(cp + 1, cp, /* /dev/tty */ 8);
+				dv = cp + 1;
+				if (stat(dv, &sb)) {
+					errorf("%s: %s: %s", "chvt",
+					    "can't find tty", go->optarg);
+				}
 			}
-			fn = dv;
 		}
 		if (!(sb.st_mode & S_IFCHR))
-			errorf("%s %s %s", "chvt: not a char", "device", fn);
+			errorf("%s: %s: %s", "chvt", "not a char device", dv);
-		if ((sb.st_uid != 0) && chown(fn, 0, 0))
+#ifndef MKSH_DISABLE_REVOKE_WARNING
-			warningf(false, "%s: %s %s", "chvt", "can't chown root", fn);
-		if (((sb.st_mode & 07777) != 0600) && chmod(fn, (mode_t)0600))
-			warningf(false, "%s: %s %s", "chvt", "can't chmod 0600", fn);
 #if HAVE_REVOKE
-		if (revoke(fn))
+		if (revoke(dv))
 #endif
 			warningf(false, "%s: %s %s", "chvt",
 			    "new shell is potentially insecure, can't revoke",
-			    fn);
+			    dv);
+#endif
 	    }
-	if ((fd = open(fn, O_RDWR)) < 0) {
+	}
+	if ((fd = open(dv, O_RDWR)) < 0) {
 		sleep(1);
-		if ((fd = open(fn, O_RDWR)) < 0)
+		if ((fd = open(dv, O_RDWR)) < 0) {
-			errorf("%s: %s %s", "chvt", "can't open", fn);
+			errorf("%s: %s %s", "chvt", "can't open", dv);
 		}
+	}
+	if (go->optarg[0] != '!') {
 		switch (fork()) {
 		case -1:
 			errorf("%s: %s %s", "chvt", "fork", "failed");
@@ -1975,9 +1984,10 @@ chvt(const char *fn)
 		default:
 			exit(0);
 		}
+	}
 	if (setsid() == -1)
 		errorf("%s: %s %s", "chvt", "setsid", "failed");
-	if (fn != dv + 1) {
+	if (go->optarg[0] != '-') {
 		if (ioctl(fd, TIOCSCTTY, NULL) == -1)
 			errorf("%s: %s %s", "chvt", "TIOCSCTTY", "failed");
 		if (tcflush(fd, TCIOFLUSH))
@@ -1988,14 +1998,7 @@ chvt(const char *fn)
 	ksh_dup2(fd, 2, false);
 	if (fd > 2)
 		close(fd);
-	{
+	rndset((unsigned long)chvt_rndsetup(go, sizeof(Getopt)));
-		register uint32_t h;
-
-		NZATInit(h);
-		NZATUpdateMem(h, &rndsetupstate, sizeof(rndsetupstate));
-		NZAATFinish(h);
-		rndset((unsigned long)h);
-	}
 	chvt_reinit();
 }
 #endif

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.315 2013/05/02 21:59:50 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.316 2013/06/03 22:28:06 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.146 2013/03/18 11:10:52 mpi Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
@@ -74,7 +74,7 @@
 .\" with -mandoc, it might implement .Mx itself, but we want to
 .\" use our own definition. And .Dd must come *first*, always.
 .\"
-.Dd $Mdocdate: May 2 2013 $
+.Dd $Mdocdate: June 3 2013 $
 .\"
 .\" Check which macro package we use, and do other -mdoc setup.
 .\"
@@ -157,7 +157,11 @@
 .Nm
 .Bk -words
 .Op Fl +abCefhiklmnprUuvXx
-.Op Fl T Ar /dev/ttyCn \*(Ba \-
+.Oo
+.Fl T Oo Ar \&! Oc Ns Ar tty
+\*(Ba
+.Ar \&\-
+.Oc
 .Op Fl +o Ar option
 .Oo
 .Fl c Ar string \*(Ba
@@ -295,16 +299,28 @@ Redirections that create files can't be used (i.e.\&
 .It Fl s
 The shell reads commands from standard input; all non-option arguments
 are positional parameters.
-.It Fl T Ar tty
+.It Fl T Ar name
 Spawn
 .Nm
 on the
 .Xr tty 4
 device given.
-Superuser only.
+The paths
+.Ar name ,
+.Pa /dev/ttyC Ns Ar name
+and
+.Pa /dev/tty Ns Ar name
+are attempted in order.
+Unless
+.Ar name
+begins with an exclamation mark
+.Pq Sq \&! ,
+this is done in a subshell and returns immediately.
 If
-.Ar tty
+.Ar name
-is a dash, detach from controlling terminal (daemonise) instead.
+is a dash
+.Pq Sq \&\- ,
+detach from controlling terminal (daemonise) instead.
 .El
 .Pp
 In addition to the above, the options described in the
@@ -6384,7 +6400,7 @@ $ /bin/sleep 666 && echo fubar
 .Ed
 .Pp
 This document attempts to describe
-.Nm mksh\ R46
+.Nm mksh\ R47
 and up,
 compiled without any options impacting functionality, such as
 .Dv MKSH_SMALL ,