• overhaul handling of special variables

• use a combination of the one-at-a-time hash and an LCG for handling
  the $RANDOM special if !HAVE_ARC4RANDOM instead of rand(3)/srand(3)
  and get rid of time(3) usage to reduce import footprint
• raise entropy state (mostly in the !HAVE_ARC4RANDOM case though…)
• simplify handling of the $RANDOM_SPECIAL generally
• tweak hash() to save a temp var for non-optimising compilers
• some int → mksh_ari_t and other type fixes
• general tweaking of code and comments

check.t

@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.332 2009/10/15 16:36:25 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.333 2009/10/17 21:16:01 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -25,7 +25,7 @@
 # http://www.research.att.com/~gsf/public/ifs.sh
 
 expected-stdout:
-	@(#)MIRBSD KSH R39 2009/10/15
+	@(#)MIRBSD KSH R39 2009/10/17
 description:
 	Check version of shell.
 stdin:

jobs.c

@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/jobs.c,v 1.61 2009/09/26 03:39:59 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/jobs.c,v 1.62 2009/10/17 21:16:02 tg Exp $");
 
 #if HAVE_KILLPG
 #define mksh_killpg		killpg
@@ -341,13 +341,16 @@ exchild(struct op *t, int flags,
 {
 	static Proc *last_proc;		/* for pipelines */
 
-	int		i;
+	int i, rv = 0, forksleep;
 	sigset_t omask;
 	Proc *p;
 	Job *j;
-	int		rv = 0;
+	struct {
-	int		forksleep;
+#if !HAVE_ARC4RANDOM
-	int		ischild;
+		pid_t thepid;
+#endif
+		unsigned char ischild;
+	} pi;
 
 	if (flags & XEXEC)
 		/* Clear XFORK|XPCLOSE|XCCLOSE|XCOPROC|XPIPEO|XPIPEI|XXCOM|XBGND
@@ -410,15 +413,17 @@ exchild(struct op *t, int flags,
 		sigprocmask(SIG_SETMASK, &omask, NULL);
 		errorf("cannot fork - try again");
 	}
-	ischild = i == 0;
+#if !HAVE_ARC4RANDOM
-	if (ischild)
+	pi.thepid =
-		p->pid = procpid = getpid();
+#endif
-	else
+	    p->pid = (pi.ischild = i == 0) ? (procpid = getpid()) : i;
-		p->pid = i;
 
 #if !HAVE_ARC4RANDOM
-	/* ensure next child gets a (slightly) different $RANDOM sequence */
+	/*
-	change_random(((unsigned long)p->pid << 1) | (ischild ? 1 : 0));
+	 * ensure next child gets a (slightly) different $RANDOM sequence
+	 * from its parent process and other child processes
+	 */
+	change_random(&pi, sizeof(pi));
 #endif
 
 #ifndef MKSH_UNEMPLOYED
@@ -440,10 +445,10 @@ exchild(struct op *t, int flags,
 #endif
 
 	/* used to close pipe input fd */
-	if (close_fd >= 0 && (((flags & XPCLOSE) && !ischild) ||
+	if (close_fd >= 0 && (((flags & XPCLOSE) && !pi.ischild) ||
-	    ((flags & XCCLOSE) && ischild)))
+	    ((flags & XCCLOSE) && pi.ischild)))
 		close(close_fd);
-	if (ischild) {		/* child */
+	if (pi.ischild) {		/* child */
 		/* Do this before restoring signal */
 		if (flags & XCOPROC)
 			coproc_cleanup(false);

main.c

@@ -33,7 +33,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.152 2009/10/02 18:08:34 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.153 2009/10/17 21:16:02 tg Exp $");
 
 extern char **environ;
 
@@ -93,7 +93,6 @@ main(int argc, const char *argv[])
 	struct block *l;
 	unsigned char restricted, errexit;
 	const char **wp;
-	pid_t ppid;
 	struct tbl *vp;
 	struct stat s_stdin;
 #if !defined(_PATH_DEFPATH) && defined(_CS_PATH)
@@ -104,11 +103,10 @@ main(int argc, const char *argv[])
 	kshpid = procpid = getpid();
 	ksheuid = geteuid();
 	kshpgrp = getpgrp();
-	ppid = getppid();
+	kshppid = getppid();
 
 #if !HAVE_ARC4RANDOM
-	change_random((unsigned long)time(NULL));
+	change_random(&kshstate_, sizeof(kshstate_));
-	change_random(((unsigned long)ksheuid << 16) | kshpid);
 #endif
 
 	/* make sure argv[] is sane */
@@ -267,15 +265,6 @@ main(int argc, const char *argv[])
 	setint(global("COLUMNS"), 0);
 	setint(global("LINES"), 0);
 	setint(global("OPTIND"), 1);
-	vp = global("RANDOM");
-#if HAVE_ARC4RANDOM
-	Flag(FARC4RANDOM) = 1;
-	/* avoid calling setspec */
-	vp->flag |= ISSET | INT_U;
-#else
-	vp->flag |= INT_U;
-	setint(vp, (mksh_ari_t)((unsigned long)kshname + 33 * ppid));
-#endif
 
 	safe_prompt = ksheuid ? "$ " : "# ";
 	vp = global("PS1");
@@ -286,10 +275,15 @@ main(int argc, const char *argv[])
 		setstr(vp, safe_prompt, KSH_RETURN_ERROR);
 	setint((vp = global("PGRP")), (mksh_uari_t)kshpgrp);
 	vp->flag |= INT_U;
-	setint((vp = global("PPID")), (mksh_uari_t)ppid);
+	setint((vp = global("PPID")), (mksh_uari_t)kshppid);
+	vp->flag |= INT_U;
+	setint((vp = global("RANDOM")), (mksh_uari_t)hash(kshname));
 	vp->flag |= INT_U;
 	setint((vp = global("USER_ID")), (mksh_uari_t)ksheuid);
 	vp->flag |= INT_U;
+#if HAVE_ARC4RANDOM
+	Flag(FARC4RANDOM) = 1;		/* initialised */
+#endif
 
 	/* Set this before parsing arguments */
 #if HAVE_SETRESUGID
@@ -1261,11 +1255,10 @@ static struct tbl *ktscan(struct table *, const char *, uint32_t,
 
 /* Bob Jenkins' one-at-a-time hash */
 uint32_t
-hash(const char *cp)
+oaathash_full(register const uint8_t *bp)
 {
 	register uint32_t h = 0;
 	register uint8_t c;
-	register const uint8_t *bp = (const uint8_t *)cp;
 
 	while ((c = *bp++)) {
 		h += c;

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.194 2009/10/10 21:17:30 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.195 2009/10/17 21:16:03 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.129 2009/05/28 06:09:06 jmc Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
@@ -48,7 +48,7 @@
 .el .xD \\$1 \\$2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8
 ..
 .\"-
-.Dd $Mdocdate: October 10 2009 $
+.Dd $Mdocdate: October 17 2009 $
 .Dt MKSH 1
 .Os MirBSD
 .Sh NAME
@@ -1810,7 +1810,7 @@ is referenced, it is assigned a 15-bit pseudo-random number, i.e. between
 0 and 32767, first, which is taken from
 .Xr arc4random 3
 if available,
-.Xr rand 3
+a Linear Congruential PRNG
 otherwise.
 .It Ev REPLY
 Default parameter for the
@@ -5736,10 +5736,8 @@ Privileged shell profile.
 .Xr arc4random 3 ,
 .Xr getopt 3 ,
 .Xr nl_langinfo 3 ,
-.Xr rand 3 ,
 .Xr setlocale 3 ,
 .Xr signal 3 ,
-.Xr srand 3 ,
 .Xr system 3 ,
 .Xr tty 4 ,
 .Xr shells 5 ,

sh.h

@@ -134,9 +134,9 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.355 2009/10/15 16:36:27 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.356 2009/10/17 21:16:04 tg Exp $");
 #endif
-#define MKSH_VERSION "R39 2009/10/15"
+#define MKSH_VERSION "R39 2009/10/17"
 
 #ifndef MKSH_INCLUDES_ONLY
 
@@ -348,13 +348,25 @@ typedef uint32_t mksh_uari_t;
 #define PATH_MAX	1024	/* pathname size */
 #endif
 
-EXTERN const char *kshname;	/* $0 */
+EXTERN struct {
-EXTERN pid_t kshpid;		/* $$, shell pid */
+	const char *kshname_;	/* $0 */
-EXTERN pid_t procpid;		/* pid of executing process */
+	pid_t kshpid_;		/* $$, shell PID */
-EXTERN pid_t kshpgrp;		/* process group of shell */
+	pid_t procpid_;		/* PID of executing process */
-EXTERN uid_t ksheuid;		/* effective uid of shell */
+	pid_t kshpgrp_;		/* process group of shell */
-EXTERN int exstat;		/* exit status */
+	uid_t ksheuid_;		/* effective UID of shell */
-EXTERN int subst_exstat;	/* exit status of last $(..)/`..` */
+	pid_t kshppid_;		/* PID of parent of shell */
+	int exstat_;		/* exit status */
+	int subst_exstat_;	/* exit status of last $(..)/`..` */
+} kshstate_;
+#define kshname		kshstate_.kshname_
+#define kshpid		kshstate_.kshpid_
+#define procpid		kshstate_.procpid_
+#define kshpgrp		kshstate_.kshpgrp_
+#define ksheuid		kshstate_.ksheuid_
+#define kshppid		kshstate_.kshppid_
+#define exstat		kshstate_.exstat_
+#define subst_exstat	kshstate_.subst_exstat_
+
 EXTERN const char *safe_prompt; /* safe prompt if PS1 substitution fails */
 EXTERN const char initvsn[] I__("KSH_VERSION=@(#)MIRBSD KSH " MKSH_VERSION);
 #define KSH_VERSION	(initvsn + /* "KSH_VERSION=@(#)" */ 16)
@@ -735,8 +747,8 @@ EXTERN size_t	current_wd_size;
  */
 #define MIN_COLS	(2 + MIN_EDIT_SPACE + 3)
 #define MIN_LINS	3
-EXTERN int x_cols I__(80);	/* tty columns */
+EXTERN mksh_ari_t x_cols I__(80);	/* tty columns */
-EXTERN int x_lins I__(-1);	/* tty lines */
+EXTERN mksh_ari_t x_lins I__(-1);	/* tty lines */
 
 /* These to avoid bracket matching problems */
 #define OPAREN	'('
@@ -1505,7 +1517,8 @@ void coproc_write_close(int);
 int coproc_getfd(int, const char **);
 void coproc_cleanup(int);
 struct temp *maketemp(Area *, Temp_type, struct temp **);
-uint32_t hash(const char *);
+#define hash(s) oaathash_full((const uint8_t *)(s))
+uint32_t oaathash_full(register const uint8_t *);
 uint32_t hashmem(const void *, size_t);
 void ktinit(struct table *, Area *, size_t);
 struct tbl *ktsearch(struct table *, const char *, uint32_t);
@@ -1601,7 +1614,7 @@ int is_wdvarname(const char *, int);
 int is_wdvarassign(const char *);
 char **makenv(void);
 #if !HAVE_ARC4RANDOM
-void change_random(unsigned long);
+void change_random(const void *, size_t);
 #endif
 void change_winsz(void);
 int array_ref_len(const char *);

var.c

@@ -22,7 +22,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/var.c,v 1.94 2009/09/27 10:31:06 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/var.c,v 1.95 2009/10/17 21:16:05 tg Exp $");
 
 /*
  * Variables
@@ -46,11 +46,11 @@ static int getint(struct tbl *, mksh_ari_t *, bool);
 static mksh_ari_t intval(struct tbl *);
 static struct tbl *arraysearch(struct tbl *, uint32_t);
 static const char *array_index_calc(const char *, bool *, uint32_t *);
-static int rnd_get(void);
+#if !HAVE_ARC4RANDOM
-#if HAVE_ARC4RANDOM
+static uint32_t oaathash_update(register uint32_t, register const uint8_t *,
-static void rnd_set(unsigned long);
+    register size_t);
-#else
+
-#define rnd_set change_random
+static uint32_t lcg_seed = 5381;
 #endif
 
 uint8_t set_refflag = 0;
@@ -972,58 +972,45 @@ makenv(void)
 	return ((char **)XPclose(denv));
 }
 
-#if HAVE_ARC4RANDOM
+#if !HAVE_ARC4RANDOM
-static int
+static uint32_t
-rnd_get(void)
+oaathash_update(register uint32_t h, register const uint8_t *cp,
+    register size_t n)
 {
-	return (arc4random() & 0x7FFF);
+	while (n--) {
-}
+		h += *cp++;
-
-static void
-rnd_set(unsigned long newval)
-{
-#if HAVE_ARC4RANDOM_PUSHB
-	if (Flag(FARC4RANDOM))
-		/* initialisation, environment import, etc. already done */
-		arc4random_pushb(&newval, sizeof(newval));
-	else
-		/* during start-up phase or somesuch */
-#endif
-	arc4random_addrandom((void *)&newval, sizeof(newval));
-}
-#else
-static int
-rnd_get(void)
-{
-	return (rand() & 0x7FFF);
-}
-
-/*
- * Called after a fork to bump the random number generator.
- * Done to ensure children will not get the same random number sequence
- * as the parent processes.
- * Also called as rnd_set - mksh R40+ no longer has the traditional
- * repeatability of randomness sequences, state is always retained.
- */
-void
-change_random(unsigned long newval)
-{
-	register unsigned int h;
-
-	h = rand();
-	while (newval) {
-		h += (newval & 0xFF);
 		h += h << 10;
 		h ^= h >> 6;
-		newval >>= 8;
 	}
 
+	return (h);
+}
+
+void
+change_random(const void *vp, size_t n)
+{
+	register uint32_t h;
+	struct {
+		const void *sp, *bp, *dp;
+		size_t dsz;
+		struct timeval tv;
+		uint32_t s;
+	} i;
+
+	i.dp = vp;
+	i.dsz = n;
+	i.s = lcg_seed;
+	i.bp = &lcg_seed;
+	i.sp = &i;
+	gettimeofday(&i.tv, NULL);
+	h = oaathash_update(oaathash_update(1, (void *)&i, sizeof(i)), vp, n);
+
+	/* oaathash_finalise */
 	h += h << 3;
 	h ^= h >> 11;
 	h += h << 15;
 
-	/* pass all of it, in case RAND_MAX is large */
+	lcg_seed = h;
-	srand(h);
 }
 #endif
 
@@ -1058,82 +1045,84 @@ static int user_lineno;		/* what user set $LINENO to */
 static void
 getspec(struct tbl *vp)
 {
-	int i;
+	register mksh_ari_t i;
+	int st;
 
-	switch ((i = special(vp->name))) {
+	switch ((st = special(vp->name))) {
 	case V_SECONDS:
-		vp->flag &= ~SPECIAL;
+		/*
-		/* On start up the value of SECONDS is used before seconds
+		 * On start up the value of SECONDS is used before
-		 * has been set - don't do anything in this case
+		 * it has been set - don't do anything in this case
 		 * (see initcoms[] in main.c).
 		 */
 		if (vp->flag & ISSET) {
 			struct timeval tv;
 
 			gettimeofday(&tv, NULL);
-			setint(vp, tv.tv_sec - seconds);
+			i = tv.tv_sec - seconds;
-		}
+		} else
-		vp->flag |= SPECIAL;
+			return;
 		break;
 	case V_RANDOM:
-		vp->flag &= ~SPECIAL;
+#if HAVE_ARC4RANDOM
-		setint(vp, rnd_get());
+		i = arc4random() & 0x7FFF;
-		vp->flag |= SPECIAL;
+#else
+		/*
+		 * this is the same Linear Congruential PRNG as Borland
+		 * C/C++ allegedly uses in its built-in rand() function
+		 */
+		i = ((lcg_seed = 22695477 * lcg_seed + 1) >> 16) & 0x7FFF;
+#endif
 		break;
 	case V_HISTSIZE:
-		vp->flag &= ~SPECIAL;
+		i = histsize;
-		setint(vp, (mksh_ari_t)histsize);
-		vp->flag |= SPECIAL;
 		break;
 	case V_OPTIND:
-		vp->flag &= ~SPECIAL;
+		i = user_opt.uoptind;
-		setint(vp, (mksh_ari_t)user_opt.uoptind);
-		vp->flag |= SPECIAL;
 		break;
 	case V_LINENO:
-		vp->flag &= ~SPECIAL;
+		i = current_lineno + user_lineno;
-		setint(vp, (mksh_ari_t)current_lineno + user_lineno);
-		vp->flag |= SPECIAL;
 		break;
 	case V_COLUMNS:
 	case V_LINES:
-		/* Do NOT export COLUMNS/LINES. Many applications
+		/*
+		 * Do NOT export COLUMNS/LINES. Many applications
 		 * check COLUMNS/LINES before checking ws.ws_col/row,
 		 * so if the app is started with C/L in the environ
 		 * and the window is then resized, the app won't
 		 * see the change cause the environ doesn't change.
 		 */
-		vp->flag &= ~SPECIAL;
 		change_winsz();
-		setint(vp, i == V_COLUMNS ? x_cols : x_lins);
+		i = st == V_COLUMNS ? x_cols : x_lins;
-		vp->flag |= SPECIAL;
 		break;
+	default:
+		/* do nothing, do not touch vp at all */
+		return;
 	}
+	vp->flag &= ~SPECIAL;
+	setint(vp, i);
+	vp->flag |= SPECIAL;
 }
 
 static void
 setspec(struct tbl *vp)
 {
-	int i;
+	mksh_ari_t i;
 	char *s;
+	int st;
 
-	switch (special(vp->name)) {
+	switch ((st = special(vp->name))) {
 	case V_PATH:
 		if (path)
 			afree(path, APERM);
 		s = str_val(vp);
 		strdupx(path, s, APERM);
 		flushcom(1);	/* clear tracked aliases */
-		break;
+		return;
 	case V_IFS:
 		setctypes(s = str_val(vp), C_IFS);
 		ifs0 = *s;
-		break;
+		return;
-	case V_OPTIND:
-		vp->flag &= ~SPECIAL;
-		getopts_reset((int)intval(vp));
-		vp->flag |= SPECIAL;
-		break;
 	case V_TMPDIR:
 		if (tmpdir) {
 			afree(tmpdir, APERM);
@@ -1151,54 +1140,84 @@ setspec(struct tbl *vp)
 				strdupx(tmpdir, s, APERM);
 		}
 		break;
-	case V_HISTSIZE:
-		vp->flag &= ~SPECIAL;
-		sethistsize((int)intval(vp));
-		vp->flag |= SPECIAL;
-		break;
 #if HAVE_PERSISTENT_HISTORY
 	case V_HISTFILE:
 		sethistfile(str_val(vp));
 		break;
 #endif
-	case V_COLUMNS:
-		vp->flag &= ~SPECIAL;
-		if ((i = intval(vp)) >= MIN_COLS)
-			x_cols = i;
-		vp->flag |= SPECIAL;
-		break;
-	case V_LINES:
-		vp->flag &= ~SPECIAL;
-		if ((i = intval(vp)) >= MIN_LINS)
-			x_lins = i;
-		vp->flag |= SPECIAL;
-		break;
-	case V_RANDOM:
-		vp->flag &= ~SPECIAL;
-		rnd_set(intval(vp));
-		vp->flag |= SPECIAL;
-		break;
-	case V_SECONDS:
-		vp->flag &= ~SPECIAL;
-		{
-			struct timeval tv;
-
-			gettimeofday(&tv, NULL);
-			seconds = tv.tv_sec - intval(vp);
-		}
-		vp->flag |= SPECIAL;
-		break;
 	case V_TMOUT:
 		/* AT&T ksh seems to do this (only listen if integer) */
 		if (vp->flag & INTEGER)
 			ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
 		break;
+
+	/* common sub-cases */
+	case V_OPTIND:
+	case V_HISTSIZE:
+	case V_COLUMNS:
+	case V_LINES:
+	case V_RANDOM:
+	case V_SECONDS:
 	case V_LINENO:
 		vp->flag &= ~SPECIAL;
-		/* The -1 is because line numbering starts at 1. */
+		i = intval(vp);
-		user_lineno = (unsigned int)intval(vp) - current_lineno - 1;
 		vp->flag |= SPECIAL;
 		break;
+	default:
+		/* do nothing, do not touch vp at all */
+		return;
+	}
+
+	/* process the singular parts of the common cases */
+
+	switch (st) {
+	case V_OPTIND:
+		getopts_reset((int)i);
+		break;
+	case V_HISTSIZE:
+		sethistsize((int)i);
+		break;
+	case V_COLUMNS:
+		if (i >= MIN_COLS)
+			x_cols = i;
+		break;
+	case V_LINES:
+		if (i >= MIN_LINS)
+			x_lins = i;
+		break;
+	case V_RANDOM:
+#if HAVE_ARC4RANDOM
+#if HAVE_ARC4RANDOM_PUSHB
+		if (Flag(FARC4RANDOM))
+			/*
+			 * things like initialisation, environment import,
+			 * etc. are already done
+			 */
+			arc4random_pushb(&i, sizeof(i));
+		else
+			/* during start-up phase or somesuch */
+#endif	/* HAVE_ARC4RANDOM_PUSHB */
+			arc4random_addrandom((void *)&i, sizeof(i));
+#else	/* !HAVE_ARC4RANDOM */
+		/*
+		 * mksh R40+ no longer has the traditional repeatability
+		 * of $RANDOM sequences, but always retains state
+		 */
+		change_random(&i, sizeof(i));
+#endif	/* !HAVE_ARC4RANDOM */
+		break;
+	case V_SECONDS:
+		{
+			struct timeval tv;
+
+			gettimeofday(&tv, NULL);
+			seconds = tv.tv_sec - i;
+		}
+		break;
+	case V_LINENO:
+		/* The -1 is because line numbering starts at 1. */
+		user_lineno = (unsigned int)i - current_lineno - 1;
+		break;
 	}
 }