X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=shell%2Fash.c;h=b27b2777ea5975e0c2ddd4ba26c9e21f0e4e5ca5;hb=e19e1935a33b117e2ee6daf9b2d79c00603333c7;hp=a799cb1a6a00f13e13d01118c07ae0a6be091ff7;hpb=f173395c4a2a643017aeae14c1d1346035986e22;p=oweals%2Fbusybox.git

diff --git a/shell/ash.c b/shell/ash.c
index a799cb1a6..b27b2777e 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -16,19 +16,6 @@
  * Original BSD copyright notice is retained at the end of this file.
  */
 
-/*
- * rewrite arith.y to micro stack based cryptic algorithm by
- * Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
- *
- * Modified by Paul Mundt <lethal@linux-sh.org> (c) 2004 to support
- * dynamic variables.
- *
- * Modified by Vladimir Oleynik <dzo@simtreas.ru> (c) 2001-2005 to be
- * used in busybox and size optimizations,
- * rewrote arith (see notes to this), added locale support,
- * rewrote dynamic variables.
- */
-
 /*
  * The following should be set to reflect the type of system you have:
  *      JOBS -> 1 if you have Berkeley job control, 0 otherwise.
@@ -63,16 +50,17 @@
 #include <paths.h>
 #include <setjmp.h>
 #include <fnmatch.h>
+#include "math.h"
 
 #if defined SINGLE_APPLET_MAIN
 /* STANDALONE does not make sense, and won't compile */
 #undef CONFIG_FEATURE_SH_STANDALONE
 #undef ENABLE_FEATURE_SH_STANDALONE
-#undef USE_FEATURE_SH_STANDALONE
-#undef SKIP_FEATURE_SH_STANDALONE(...)
+#undef IF_FEATURE_SH_STANDALONE
+#undef IF_NOT_FEATURE_SH_STANDALONE(...)
 #define ENABLE_FEATURE_SH_STANDALONE 0
-#define USE_FEATURE_SH_STANDALONE(...)
-#define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__
+#define IF_FEATURE_SH_STANDALONE(...)
+#define IF_NOT_FEATURE_SH_STANDALONE(...) __VA_ARGS__
 #endif
 
 #ifndef PIPE_BUF
@@ -260,6 +248,12 @@ static void trace_printf(const char *fmt, ...);
 static void trace_vprintf(const char *fmt, va_list va);
 # define TRACE(param)    trace_printf param
 # define TRACEV(param)   trace_vprintf param
+# define close(fd) do { \
+	int dfd = (fd); \
+	if (close(dfd) < 0) \
+		bb_error_msg("bug on %d: closing %d(%x)", \
+			__LINE__, dfd, dfd); \
+} while (0)
 #else
 # define TRACE(param)
 # define TRACEV(param)
@@ -355,39 +349,25 @@ raise_interrupt(void)
 } while (0)
 #endif
 
-#if ENABLE_ASH_OPTIMIZE_FOR_SIZE
-static void
+static IF_ASH_OPTIMIZE_FOR_SIZE(inline) void
 int_on(void)
 {
+	xbarrier();
 	if (--suppressint == 0 && intpending) {
 		raise_interrupt();
 	}
 }
 #define INT_ON int_on()
-static void
+static IF_ASH_OPTIMIZE_FOR_SIZE(inline) void
 force_int_on(void)
 {
+	xbarrier();
 	suppressint = 0;
 	if (intpending)
 		raise_interrupt();
 }
 #define FORCE_INT_ON force_int_on()
 
-#else /* !ASH_OPTIMIZE_FOR_SIZE */
-
-#define INT_ON do { \
-	xbarrier(); \
-	if (--suppressint == 0 && intpending) \
-		raise_interrupt(); \
-} while (0)
-#define FORCE_INT_ON do { \
-	xbarrier(); \
-	suppressint = 0; \
-	if (intpending) \
-		raise_interrupt(); \
-} while (0)
-#endif /* !ASH_OPTIMIZE_FOR_SIZE */
-
 #define SAVE_INT(v) ((v) = suppressint)
 
 #define RESTORE_INT(v) do { \
@@ -1118,6 +1098,14 @@ ash_msg_and_raise_error(const char *msg, ...)
 	va_end(ap);
 }
 
+static void raise_error_syntax(const char *) NORETURN;
+static void
+raise_error_syntax(const char *msg)
+{
+	ash_msg_and_raise_error("syntax error: %s", msg);
+	/* NOTREACHED */
+}
+
 static void ash_msg_and_raise(int, const char *, ...) NORETURN;
 static void
 ash_msg_and_raise(int cond, const char *msg, ...)
@@ -1992,7 +1980,7 @@ findvar(struct var **vpp, const char *name)
 /*
  * Find the value of a variable.  Returns NULL if not set.
  */
-static char *
+static const char *
 lookupvar(const char *name)
 {
 	struct var *v;
@@ -2018,7 +2006,7 @@ lookupvar(const char *name)
 /*
  * Search the environment of a builtin command.
  */
-static char *
+static const char *
 bltinlookup(const char *name)
 {
 	struct strlist *sp;
@@ -2631,7 +2619,7 @@ pwdcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 #define USE_SIT_FUNCTION
 #endif
 
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 static const char S_I_T[][4] = {
 #if ENABLE_ASH_ALIAS
 	{ CSPCL, CIGN, CIGN, CIGN },            /* 0, PEOA */
@@ -2675,7 +2663,7 @@ static const char S_I_T[][3] = {
 	{ CCTL, CCTL, CCTL }                    /* 14, CTLESC ... */
 #endif
 };
-#endif /* ASH_MATH_SUPPORT */
+#endif /* SH_MATH_SUPPORT */
 
 #ifdef USE_SIT_FUNCTION
 
@@ -2701,23 +2689,26 @@ SIT(int c, int syntax)
 	const char *s;
 	int indx;
 
-	if (c == PEOF)          /* 2^8+2 */
+	if (c == PEOF) {         /* 2^8+2 */
 		return CENDFILE;
+	}
 #if ENABLE_ASH_ALIAS
-	if (c == PEOA)          /* 2^8+1 */
+	if (c == PEOA) {         /* 2^8+1 */
 		indx = 0;
-	else
+	} else
 #endif
-
-	if ((unsigned char)c >= (unsigned char)(CTLESC)
-	 && (unsigned char)c <= (unsigned char)(CTLQUOTEMARK)
-	) {
-		return CCTL;
+	{
+		if ((unsigned char)c >= (unsigned char)(CTLESC)
+		 && (unsigned char)c <= (unsigned char)(CTLQUOTEMARK)
+		) {
+			return CCTL;
+		}
+		s = strchrnul(spec_symbls, c);
+		if (*s == '\0') {
+			return CWORD;
+		}
+		indx = syntax_index_table[s - spec_symbls];
 	}
-	s = strchrnul(spec_symbls, c);
-	if (*s == '\0')
-		return CWORD;
-	indx = syntax_index_table[s - spec_symbls];
 	return S_I_T[indx][syntax];
 }
 
@@ -3020,7 +3011,7 @@ static const char syntax_index_table[258] = {
 	/* 257   127      */ CWORD_CWORD_CWORD_CWORD,
 };
 
-#define SIT(c, syntax) (S_I_T[(int)syntax_index_table[((int)c)+SYNBASE]][syntax])
+#define SIT(c, syntax) (S_I_T[(int)syntax_index_table[(int)(c) + SYNBASE]][syntax])
 
 #endif  /* USE_SIT_FUNCTION */
 
@@ -4228,7 +4219,7 @@ cmdputs(const char *s)
 	static const char vstype[VSTYPE + 1][3] = {
 		"", "}", "-", "+", "?", "=",
 		"%", "%%", "#", "##"
-		USE_ASH_BASH_COMPAT(, ":", "/", "//")
+		IF_ASH_BASH_COMPAT(, ":", "/", "//")
 	};
 
 	const char *p, *str;
@@ -4267,7 +4258,7 @@ cmdputs(const char *s)
 		case CTLBACKQ+CTLQUOTE:
 			str = "\"$(...)\"";
 			goto dostr;
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 		case CTLARI:
 			str = "$((";
 			goto dostr;
@@ -5142,7 +5133,9 @@ redirect(union node *redir, int flags)
 		if (newfd < 0) {
 			/* NTOFD/NFROMFD: copy redir->ndup.dupfd to fd */
 			if (redir->ndup.dupfd < 0) { /* "fd>&-" */
-				close(fd);
+				/* Don't want to trigger debugging */
+				if (fd != -1)
+					close(fd);
 			} else {
 				copyfd(redir->ndup.dupfd, fd | COPYFD_EXACT);
 			}
@@ -5195,7 +5188,7 @@ popredir(int drop, int restore)
 				/*close(fd);*/
 				copyfd(copy, fd | COPYFD_EXACT);
 			}
-			close(copy);
+			close(copy & ~COPYFD_RESTORE);
 		}
 	}
 	redirlist = rp->next;
@@ -5250,17 +5243,33 @@ redirectsafe(union node *redir, int flags)
  * We have to deal with backquotes, shell variables, and file metacharacters.
  */
 
-#if ENABLE_ASH_MATH_SUPPORT_64
-typedef int64_t arith_t;
-#define arith_t_type long long
-#else
-typedef long arith_t;
-#define arith_t_type long
-#endif
+#if ENABLE_SH_MATH_SUPPORT
+static arith_t
+ash_arith(const char *s)
+{
+	arith_eval_hooks_t math_hooks;
+	arith_t result;
+	int errcode = 0;
+
+	math_hooks.lookupvar = lookupvar;
+	math_hooks.setvar = setvar;
+	math_hooks.endofname = endofname;
 
-#if ENABLE_ASH_MATH_SUPPORT
-static arith_t dash_arith(const char *);
-static arith_t arith(const char *expr, int *perrcode);
+	INT_OFF;
+	result = arith(s, &errcode, &math_hooks);
+	if (errcode < 0) {
+		if (errcode == -3)
+			ash_msg_and_raise_error("exponent less than 0");
+		if (errcode == -2)
+			ash_msg_and_raise_error("divide by zero");
+		if (errcode == -5)
+			ash_msg_and_raise_error("expression recursion loop detected");
+		raise_error_syntax(s);
+	}
+	INT_ON;
+
+	return result;
+}
 #endif
 
 /*
@@ -5320,11 +5329,7 @@ cvtnum(arith_t num)
 	int len;
 
 	expdest = makestrspace(32, expdest);
-#if ENABLE_ASH_MATH_SUPPORT_64
-	len = fmtstr(expdest, 32, "%lld", (long long) num);
-#else
-	len = fmtstr(expdest, 32, "%ld", num);
-#endif
+	len = fmtstr(expdest, 32, arith_t_fmt, num);
 	STADJUST(len, expdest);
 	return len;
 }
@@ -5688,7 +5693,7 @@ expbackq(union node *cmd, int quoted, int quotes)
 		stackblock() + startloc));
 }
 
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 /*
  * Expand arithmetic expression.  Backup to start of expression,
  * evaluate, place result in (backed up) result, adjust string position.
@@ -5743,7 +5748,7 @@ expari(int quotes)
 	if (quotes)
 		rmescapes(p + 2);
 
-	len = cvtnum(dash_arith(p + 2));
+	len = cvtnum(ash_arith(p + 2));
 
 	if (flag != '"')
 		recordregion(begoff, begoff + len, 0);
@@ -5774,7 +5779,7 @@ argstr(char *p, int flag, struct strlist *var_str_list)
 		CTLVAR,
 		CTLBACKQ,
 		CTLBACKQ | CTLQUOTE,
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 		CTLENDARI,
 #endif
 		0
@@ -5811,7 +5816,7 @@ argstr(char *p, int flag, struct strlist *var_str_list)
 		length += strcspn(p + length, reject);
 		c = p[length];
 		if (c && (!(c & 0x80)
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 					|| c == CTLENDARI
 #endif
 		   )) {
@@ -5889,7 +5894,7 @@ argstr(char *p, int flag, struct strlist *var_str_list)
 			expbackq(argbackq->n, c, quotes);
 			argbackq = argbackq->next;
 			goto start;
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 		case CTLENDARI:
 			p--;
 			expari(quotes);
@@ -6064,9 +6069,9 @@ subevalvar(char *p, char *str, int strloc, int subtype,
 	char *startp;
 	char *loc;
 	char *rmesc, *rmescend;
-	USE_ASH_BASH_COMPAT(char *repl = NULL;)
-	USE_ASH_BASH_COMPAT(char null = '\0';)
-	USE_ASH_BASH_COMPAT(int pos, len, orig_len;)
+	IF_ASH_BASH_COMPAT(char *repl = NULL;)
+	IF_ASH_BASH_COMPAT(char null = '\0';)
+	IF_ASH_BASH_COMPAT(int pos, len, orig_len;)
 	int saveherefd = herefd;
 	int amount, workloc, resetloc;
 	int zero;
@@ -6152,7 +6157,7 @@ subevalvar(char *p, char *str, int strloc, int subtype,
 	 * stack will need rebasing, and we'll need to remove our work
 	 * areas each time
 	 */
- USE_ASH_BASH_COMPAT(restart:)
+ IF_ASH_BASH_COMPAT(restart:)
 
 	amount = expdest - ((char *)stackblock() + resetloc);
 	STADJUST(-amount, expdest);
@@ -6283,7 +6288,7 @@ static ssize_t
 varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
 {
 	int num;
-	char *p;
+	const char *p;
 	int i;
 	int sep = 0;
 	int sepq = 0;
@@ -6316,14 +6321,13 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
 		len = cvtnum(num);
 		break;
 	case '-':
-		p = makestrspace(NOPTS, expdest);
+		expdest = makestrspace(NOPTS, expdest);
 		for (i = NOPTS - 1; i >= 0; i--) {
 			if (optlist[i]) {
-				USTPUTC(optletters(i), p);
+				USTPUTC(optletters(i), expdest);
 				len++;
 			}
 		}
-		expdest = p;
 		break;
 	case '@':
 		if (sep)
@@ -7079,7 +7083,7 @@ static int builtinloc = -1;     /* index in path of %builtin, or -1 */
 
 
 static void
-tryexec(USE_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char **envp)
+tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char **envp)
 {
 	int repeated = 0;
 
@@ -7151,13 +7155,13 @@ shellexec(char **argv, const char *path, int idx)
 	 || (applet_no = find_applet_by_name(argv[0])) >= 0
 #endif
 	) {
-		tryexec(USE_FEATURE_SH_STANDALONE(applet_no,) argv[0], argv, envp);
+		tryexec(IF_FEATURE_SH_STANDALONE(applet_no,) argv[0], argv, envp);
 		e = errno;
 	} else {
 		e = ENOENT;
 		while ((cmdname = padvance(&path, argv[0])) != NULL) {
 			if (--idx < 0 && pathopt == NULL) {
-				tryexec(USE_FEATURE_SH_STANDALONE(-1,) cmdname, argv, envp);
+				tryexec(IF_FEATURE_SH_STANDALONE(-1,) cmdname, argv, envp);
 				if (errno != ENOENT && errno != ENOTDIR)
 					e = errno;
 			}
@@ -8416,7 +8420,9 @@ evalpipe(union node *n, int flags)
 		if (prevfd >= 0)
 			close(prevfd);
 		prevfd = pip[0];
-		close(pip[1]);
+		/* Don't want to trigger debugging */
+		if (pip[1] != -1)
+			close(pip[1]);
 	}
 	if (n->npipe.pipe_backgnd == 0) {
 		exitstatus = waitforjob(jp);
@@ -8700,7 +8706,7 @@ static int getoptscmd(int, char **);
 #if !ENABLE_FEATURE_SH_EXTRA_QUIET
 static int helpcmd(int, char **);
 #endif
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 static int letcmd(int, char **);
 #endif
 static int readcmd(int, char **);
@@ -8782,7 +8788,7 @@ static const struct builtincmd builtintab[] = {
 	{ BUILTIN_REGULAR       "jobs", jobscmd },
 	{ BUILTIN_REGULAR       "kill", killcmd },
 #endif
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 	{ BUILTIN_NOSPEC        "let", letcmd },
 #endif
 	{ BUILTIN_ASSIGN        "local", localcmd },
@@ -10149,14 +10155,6 @@ static struct heredoc *heredoc;
  */
 #define NEOF ((union node *)&tokpushback)
 
-static void raise_error_syntax(const char *) NORETURN;
-static void
-raise_error_syntax(const char *msg)
-{
-	ash_msg_and_raise_error("syntax error: %s", msg);
-	/* NOTREACHED */
-}
-
 /*
  * Called when an unexpected token is read during the parse.  The argument
  * is the token that is expected, or -1 if more than one type of token can
@@ -10791,7 +10789,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
 	int parenlevel;      /* levels of parens in arithmetic */
 	int dqvarnest;       /* levels of variables expansion within double quotes */
 
-	USE_ASH_BASH_COMPAT(smallint bash_dollar_squote = 0;)
+	IF_ASH_BASH_COMPAT(smallint bash_dollar_squote = 0;)
 
 #if __GNUC__
 	/* Avoid longjmp clobbering */
@@ -10897,7 +10895,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
 				dblquote = 1;
 				goto quotemark;
 			case CENDQUOTE:
-				USE_ASH_BASH_COMPAT(bash_dollar_squote = 0;)
+				IF_ASH_BASH_COMPAT(bash_dollar_squote = 0;)
 				if (eofmark != NULL && arinest == 0
 				 && varnest == 0
 				) {
@@ -10925,7 +10923,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
 					USTPUTC(c, out);
 				}
 				break;
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 			case CLP:       /* '(' in arithmetic */
 				parenlevel++;
 				USTPUTC(c, out);
@@ -10981,7 +10979,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
 		} /* for (;;) */
 	}
  endword:
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 	if (syntax == ARISYNTAX)
 		raise_error_syntax("missing '))'");
 #endif
@@ -10996,7 +10994,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
 	len = out - (char *)stackblock();
 	out = stackblock();
 	if (eofmark == NULL) {
-		if ((c == '>' || c == '<' USE_ASH_BASH_COMPAT( || c == 0x100 + '>'))
+		if ((c == '>' || c == '<' IF_ASH_BASH_COMPAT( || c == 0x100 + '>'))
 		 && quotef == 0
 		) {
 			if (isdigit_str9(out)) {
@@ -11158,7 +11156,7 @@ parsesub: {
 		pungetc();
 	} else if (c == '(') {  /* $(command) or $((arith)) */
 		if (pgetc() == '(') {
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 			PARSEARITH();
 #else
 			raise_error_syntax("you disabled math support for $((arith)) syntax");
@@ -11413,7 +11411,7 @@ parsebackq: {
 	goto parsebackq_newreturn;
 }
 
-#if ENABLE_ASH_MATH_SUPPORT
+#if ENABLE_SH_MATH_SUPPORT
 /*
  * Parse an arithmetic expansion (indicate start of one and set state)
  */
@@ -11490,7 +11488,7 @@ xxreadtoken(void)
 	startlinno = g_parsefile->linno;
 	for (;;) {                      /* until token or start of word found */
 		c = pgetc_fast();
-		if (c == ' ' || c == '\t' USE_ASH_ALIAS( || c == PEOA))
+		if (c == ' ' || c == '\t' IF_ASH_ALIAS( || c == PEOA))
 			continue;
 
 		if (c == '#') {
@@ -11850,7 +11848,9 @@ cmdloop(int top)
 #endif
 		}
 		n = parsecmd(inter);
-		/* showtree(n); DEBUG */
+#if DEBUG
+		showtree(n);
+#endif
 		if (n == NEOF) {
 			if (!top || numeof >= 50)
 				break;
@@ -12232,7 +12232,9 @@ helpcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 	unsigned col;
 	unsigned i;
 
-	out1fmt("\nBuilt-in commands:\n-------------------\n");
+	out1fmt("\n"
+		"Built-in commands:\n"
+		"------------------\n");
 	for (col = 0, i = 0; i < ARRAY_SIZE(builtintab); i++) {
 		col += out1fmt("%c%s", ((col == 0) ? '\t' : ' '),
 					builtintab[i].name + 1);
@@ -12374,34 +12376,12 @@ timescmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 	return 0;
 }
 
-#if ENABLE_ASH_MATH_SUPPORT
-static arith_t
-dash_arith(const char *s)
-{
-	arith_t result;
-	int errcode = 0;
-
-	INT_OFF;
-	result = arith(s, &errcode);
-	if (errcode < 0) {
-		if (errcode == -3)
-			ash_msg_and_raise_error("exponent less than 0");
-		if (errcode == -2)
-			ash_msg_and_raise_error("divide by zero");
-		if (errcode == -5)
-			ash_msg_and_raise_error("expression recursion loop detected");
-		raise_error_syntax(s);
-	}
-	INT_ON;
-
-	return result;
-}
-
+#if ENABLE_SH_MATH_SUPPORT
 /*
- *  The let builtin. partial stolen from GNU Bash, the Bourne Again SHell.
- *  Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc.
+ * The let builtin. partial stolen from GNU Bash, the Bourne Again SHell.
+ * Copyright (C) 1987, 1989, 1991 Free Software Foundation, Inc.
  *
- *  Copyright (C) 2003 Vladimir Oleynik <dzo@simtreas.ru>
+ * Copyright (C) 2003 Vladimir Oleynik <dzo@simtreas.ru>
  */
 static int
 letcmd(int argc UNUSED_PARAM, char **argv)
@@ -12412,12 +12392,12 @@ letcmd(int argc UNUSED_PARAM, char **argv)
 	if (!*argv)
 		ash_msg_and_raise_error("expression expected");
 	do {
-		i = dash_arith(*argv);
+		i = ash_arith(*argv);
 	} while (*++argv);
 
 	return !i;
 }
-#endif /* ASH_MATH_SUPPORT */
+#endif /* SH_MATH_SUPPORT */
 
 
 /* ============ miscbltin.c
@@ -12474,8 +12454,8 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 	rflag = 0;
 	prompt = NULL;
 	while ((i = nextopt("p:u:r"
-		USE_ASH_READ_TIMEOUT("t:")
-		USE_ASH_READ_NCHARS("n:s")
+		IF_ASH_READ_TIMEOUT("t:")
+		IF_ASH_READ_NCHARS("n:s")
 	)) != '\0') {
 		switch (i) {
 		case 'p':
@@ -12564,7 +12544,7 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 #endif
 
 	status = 0;
-	startword = 1;
+	startword = 2;
 	backslash = 0;
 #if ENABLE_ASH_READ_TIMEOUT
 	if (timeout) /* NB: ensuring end_ms is nonzero */
@@ -12572,6 +12552,8 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 #endif
 	STARTSTACKSTR(p);
 	do {
+		const char *is_ifs;
+
 #if ENABLE_ASH_READ_TIMEOUT
 		if (end_ms) {
 			struct pollfd pfd[1];
@@ -12601,25 +12583,36 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 			continue;
 		}
 		if (!rflag && c == '\\') {
-			backslash++;
+			backslash = 1;
 			continue;
 		}
 		if (c == '\n')
 			break;
-		if (startword && *ifs == ' ' && strchr(ifs, c)) {
-			continue;
+		/* $IFS splitting */
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
+		is_ifs = strchr(ifs, c);
+		if (startword && is_ifs) {
+			if (isspace(c))
+				continue;
+			/* it is a non-space ifs char */
+			startword--;
+			if (startword == 1) /* first one? */
+				continue; /* yes, it is not next word yet */
 		}
 		startword = 0;
-		if (ap[1] != NULL && strchr(ifs, c) != NULL) {
+		if (ap[1] != NULL && is_ifs) {
+			const char *beg;
 			STACKSTRNUL(p);
-			setvar(*ap, stackblock(), 0);
+			beg = stackblock();
+			setvar(*ap, beg, 0);
 			ap++;
-			startword = 1;
+			/* can we skip one non-space ifs char? (2: yes) */
+			startword = isspace(c) ? 2 : 1;
 			STARTSTACKSTR(p);
-		} else {
- put:
-			STPUTC(c, p);
+			continue;
 		}
+ put:
+		STPUTC(c, p);
 	}
 /* end of do {} while: */
 #if ENABLE_ASH_READ_NCHARS
@@ -12633,8 +12626,8 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 #endif
 
 	STACKSTRNUL(p);
-	/* Remove trailing blanks */
-	while ((char *)stackblock() <= --p && strchr(ifs, *p) != NULL)
+	/* Remove trailing space ifs chars */
+	while ((char *)stackblock() <= --p && isspace(*p) && strchr(ifs, *p) != NULL)
 		*p = '\0';
 	setvar(*ap, stackblock(), 0);
 	while (*++ap != NULL)
@@ -12653,6 +12646,8 @@ umaskcmd(int argc UNUSED_PARAM, char **argv)
 		S_IROTH, S_IWOTH, S_IXOTH
 	};
 
+	/* TODO: use bb_parse_mode() instead */
+
 	char *ap;
 	mode_t mask;
 	int i;
@@ -12719,7 +12714,6 @@ umaskcmd(int argc UNUSED_PARAM, char **argv)
  *
  * Public domain.
  */
-
 struct limits {
 	uint8_t cmd;          /* RLIMIT_xxx fit into it */
 	uint8_t factor_shift; /* shift by to get rlim_{cur,max} values */
@@ -12928,654 +12922,6 @@ ulimitcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 	return 0;
 }
 
-
-/* ============ Math support */
-
-#if ENABLE_ASH_MATH_SUPPORT
-
-/* Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
-
-   Permission is hereby granted, free of charge, to any person obtaining
-   a copy of this software and associated documentation files (the
-   "Software"), to deal in the Software without restriction, including
-   without limitation the rights to use, copy, modify, merge, publish,
-   distribute, sublicense, and/or sell copies of the Software, and to
-   permit persons to whom the Software is furnished to do so, subject to
-   the following conditions:
-
-   The above copyright notice and this permission notice shall be
-   included in all copies or substantial portions of the Software.
-
-   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-   IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-   CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-   TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-   SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-*/
-
-/* This is my infix parser/evaluator. It is optimized for size, intended
- * as a replacement for yacc-based parsers. However, it may well be faster
- * than a comparable parser written in yacc. The supported operators are
- * listed in #defines below. Parens, order of operations, and error handling
- * are supported. This code is thread safe. The exact expression format should
- * be that which POSIX specifies for shells. */
-
-/* The code uses a simple two-stack algorithm. See
- * http://www.onthenet.com.au/~grahamis/int2008/week02/lect02.html
- * for a detailed explanation of the infix-to-postfix algorithm on which
- * this is based (this code differs in that it applies operators immediately
- * to the stack instead of adding them to a queue to end up with an
- * expression). */
-
-/* To use the routine, call it with an expression string and error return
- * pointer */
-
-/*
- * Aug 24, 2001              Manuel Novoa III
- *
- * Reduced the generated code size by about 30% (i386) and fixed several bugs.
- *
- * 1) In arith_apply():
- *    a) Cached values of *numptr and &(numptr[-1]).
- *    b) Removed redundant test for zero denominator.
- *
- * 2) In arith():
- *    a) Eliminated redundant code for processing operator tokens by moving
- *       to a table-based implementation.  Also folded handling of parens
- *       into the table.
- *    b) Combined all 3 loops which called arith_apply to reduce generated
- *       code size at the cost of speed.
- *
- * 3) The following expressions were treated as valid by the original code:
- *       1()  ,    0!  ,    1 ( *3 )   .
- *    These bugs have been fixed by internally enclosing the expression in
- *    parens and then checking that all binary ops and right parens are
- *    preceded by a valid expression (NUM_TOKEN).
- *
- * Note: It may be desirable to replace Aaron's test for whitespace with
- * ctype's isspace() if it is used by another busybox applet or if additional
- * whitespace chars should be considered.  Look below the "#include"s for a
- * precompiler test.
- */
-
-/*
- * Aug 26, 2001              Manuel Novoa III
- *
- * Return 0 for null expressions.  Pointed out by Vladimir Oleynik.
- *
- * Merge in Aaron's comments previously posted to the busybox list,
- * modified slightly to take account of my changes to the code.
- *
- */
-
-/*
- *  (C) 2003 Vladimir Oleynik <dzo@simtreas.ru>
- *
- * - allow access to variable,
- *   used recursive find value indirection (c=2*2; a="c"; $((a+=2)) produce 6)
- * - realize assign syntax (VAR=expr, +=, *= etc)
- * - realize exponentiation (** operator)
- * - realize comma separated - expr, expr
- * - realise ++expr --expr expr++ expr--
- * - realise expr ? expr : expr (but, second expr calculate always)
- * - allow hexadecimal and octal numbers
- * - was restored loses XOR operator
- * - remove one goto label, added three ;-)
- * - protect $((num num)) as true zero expr (Manuel`s error)
- * - always use special isspace(), see comment from bash ;-)
- */
-
-#define arith_isspace(arithval) \
-	(arithval == ' ' || arithval == '\n' || arithval == '\t')
-
-typedef unsigned char operator;
-
-/* An operator's token id is a bit of a bitfield. The lower 5 bits are the
- * precedence, and 3 high bits are an ID unique across operators of that
- * precedence. The ID portion is so that multiple operators can have the
- * same precedence, ensuring that the leftmost one is evaluated first.
- * Consider * and /. */
-
-#define tok_decl(prec,id) (((id)<<5)|(prec))
-#define PREC(op) ((op) & 0x1F)
-
-#define TOK_LPAREN tok_decl(0,0)
-
-#define TOK_COMMA tok_decl(1,0)
-
-#define TOK_ASSIGN tok_decl(2,0)
-#define TOK_AND_ASSIGN tok_decl(2,1)
-#define TOK_OR_ASSIGN tok_decl(2,2)
-#define TOK_XOR_ASSIGN tok_decl(2,3)
-#define TOK_PLUS_ASSIGN tok_decl(2,4)
-#define TOK_MINUS_ASSIGN tok_decl(2,5)
-#define TOK_LSHIFT_ASSIGN tok_decl(2,6)
-#define TOK_RSHIFT_ASSIGN tok_decl(2,7)
-
-#define TOK_MUL_ASSIGN tok_decl(3,0)
-#define TOK_DIV_ASSIGN tok_decl(3,1)
-#define TOK_REM_ASSIGN tok_decl(3,2)
-
-/* all assign is right associativity and precedence eq, but (7+3)<<5 > 256 */
-#define convert_prec_is_assing(prec) do { if (prec == 3) prec = 2; } while (0)
-
-/* conditional is right associativity too */
-#define TOK_CONDITIONAL tok_decl(4,0)
-#define TOK_CONDITIONAL_SEP tok_decl(4,1)
-
-#define TOK_OR tok_decl(5,0)
-
-#define TOK_AND tok_decl(6,0)
-
-#define TOK_BOR tok_decl(7,0)
-
-#define TOK_BXOR tok_decl(8,0)
-
-#define TOK_BAND tok_decl(9,0)
-
-#define TOK_EQ tok_decl(10,0)
-#define TOK_NE tok_decl(10,1)
-
-#define TOK_LT tok_decl(11,0)
-#define TOK_GT tok_decl(11,1)
-#define TOK_GE tok_decl(11,2)
-#define TOK_LE tok_decl(11,3)
-
-#define TOK_LSHIFT tok_decl(12,0)
-#define TOK_RSHIFT tok_decl(12,1)
-
-#define TOK_ADD tok_decl(13,0)
-#define TOK_SUB tok_decl(13,1)
-
-#define TOK_MUL tok_decl(14,0)
-#define TOK_DIV tok_decl(14,1)
-#define TOK_REM tok_decl(14,2)
-
-/* exponent is right associativity */
-#define TOK_EXPONENT tok_decl(15,1)
-
-/* For now unary operators. */
-#define UNARYPREC 16
-#define TOK_BNOT tok_decl(UNARYPREC,0)
-#define TOK_NOT tok_decl(UNARYPREC,1)
-
-#define TOK_UMINUS tok_decl(UNARYPREC+1,0)
-#define TOK_UPLUS tok_decl(UNARYPREC+1,1)
-
-#define PREC_PRE (UNARYPREC+2)
-
-#define TOK_PRE_INC tok_decl(PREC_PRE, 0)
-#define TOK_PRE_DEC tok_decl(PREC_PRE, 1)
-
-#define PREC_POST (UNARYPREC+3)
-
-#define TOK_POST_INC tok_decl(PREC_POST, 0)
-#define TOK_POST_DEC tok_decl(PREC_POST, 1)
-
-#define SPEC_PREC (UNARYPREC+4)
-
-#define TOK_NUM tok_decl(SPEC_PREC, 0)
-#define TOK_RPAREN tok_decl(SPEC_PREC, 1)
-
-#define NUMPTR (*numstackptr)
-
-static int
-tok_have_assign(operator op)
-{
-	operator prec = PREC(op);
-
-	convert_prec_is_assing(prec);
-	return (prec == PREC(TOK_ASSIGN) ||
-			prec == PREC_PRE || prec == PREC_POST);
-}
-
-static int
-is_right_associativity(operator prec)
-{
-	return (prec == PREC(TOK_ASSIGN) || prec == PREC(TOK_EXPONENT)
-	        || prec == PREC(TOK_CONDITIONAL));
-}
-
-typedef struct {
-	arith_t val;
-	arith_t contidional_second_val;
-	char contidional_second_val_initialized;
-	char *var;      /* if NULL then is regular number,
-			   else is variable name */
-} v_n_t;
-
-typedef struct chk_var_recursive_looped_t {
-	const char *var;
-	struct chk_var_recursive_looped_t *next;
-} chk_var_recursive_looped_t;
-
-static chk_var_recursive_looped_t *prev_chk_var_recursive;
-
-static int
-arith_lookup_val(v_n_t *t)
-{
-	if (t->var) {
-		const char * p = lookupvar(t->var);
-
-		if (p) {
-			int errcode;
-
-			/* recursive try as expression */
-			chk_var_recursive_looped_t *cur;
-			chk_var_recursive_looped_t cur_save;
-
-			for (cur = prev_chk_var_recursive; cur; cur = cur->next) {
-				if (strcmp(cur->var, t->var) == 0) {
-					/* expression recursion loop detected */
-					return -5;
-				}
-			}
-			/* save current lookuped var name */
-			cur = prev_chk_var_recursive;
-			cur_save.var = t->var;
-			cur_save.next = cur;
-			prev_chk_var_recursive = &cur_save;
-
-			t->val = arith (p, &errcode);
-			/* restore previous ptr after recursiving */
-			prev_chk_var_recursive = cur;
-			return errcode;
-		}
-		/* allow undefined var as 0 */
-		t->val = 0;
-	}
-	return 0;
-}
-
-/* "applying" a token means performing it on the top elements on the integer
- * stack. For a unary operator it will only change the top element, but a
- * binary operator will pop two arguments and push a result */
-static int
-arith_apply(operator op, v_n_t *numstack, v_n_t **numstackptr)
-{
-	v_n_t *numptr_m1;
-	arith_t numptr_val, rez;
-	int ret_arith_lookup_val;
-
-	/* There is no operator that can work without arguments */
-	if (NUMPTR == numstack) goto err;
-	numptr_m1 = NUMPTR - 1;
-
-	/* check operand is var with noninteger value */
-	ret_arith_lookup_val = arith_lookup_val(numptr_m1);
-	if (ret_arith_lookup_val)
-		return ret_arith_lookup_val;
-
-	rez = numptr_m1->val;
-	if (op == TOK_UMINUS)
-		rez *= -1;
-	else if (op == TOK_NOT)
-		rez = !rez;
-	else if (op == TOK_BNOT)
-		rez = ~rez;
-	else if (op == TOK_POST_INC || op == TOK_PRE_INC)
-		rez++;
-	else if (op == TOK_POST_DEC || op == TOK_PRE_DEC)
-		rez--;
-	else if (op != TOK_UPLUS) {
-		/* Binary operators */
-
-		/* check and binary operators need two arguments */
-		if (numptr_m1 == numstack) goto err;
-
-		/* ... and they pop one */
-		--NUMPTR;
-		numptr_val = rez;
-		if (op == TOK_CONDITIONAL) {
-			if (!numptr_m1->contidional_second_val_initialized) {
-				/* protect $((expr1 ? expr2)) without ": expr" */
-				goto err;
-			}
-			rez = numptr_m1->contidional_second_val;
-		} else if (numptr_m1->contidional_second_val_initialized) {
-			/* protect $((expr1 : expr2)) without "expr ? " */
-			goto err;
-		}
-		numptr_m1 = NUMPTR - 1;
-		if (op != TOK_ASSIGN) {
-			/* check operand is var with noninteger value for not '=' */
-			ret_arith_lookup_val = arith_lookup_val(numptr_m1);
-			if (ret_arith_lookup_val)
-				return ret_arith_lookup_val;
-		}
-		if (op == TOK_CONDITIONAL) {
-			numptr_m1->contidional_second_val = rez;
-		}
-		rez = numptr_m1->val;
-		if (op == TOK_BOR || op == TOK_OR_ASSIGN)
-			rez |= numptr_val;
-		else if (op == TOK_OR)
-			rez = numptr_val || rez;
-		else if (op == TOK_BAND || op == TOK_AND_ASSIGN)
-			rez &= numptr_val;
-		else if (op == TOK_BXOR || op == TOK_XOR_ASSIGN)
-			rez ^= numptr_val;
-		else if (op == TOK_AND)
-			rez = rez && numptr_val;
-		else if (op == TOK_EQ)
-			rez = (rez == numptr_val);
-		else if (op == TOK_NE)
-			rez = (rez != numptr_val);
-		else if (op == TOK_GE)
-			rez = (rez >= numptr_val);
-		else if (op == TOK_RSHIFT || op == TOK_RSHIFT_ASSIGN)
-			rez >>= numptr_val;
-		else if (op == TOK_LSHIFT || op == TOK_LSHIFT_ASSIGN)
-			rez <<= numptr_val;
-		else if (op == TOK_GT)
-			rez = (rez > numptr_val);
-		else if (op == TOK_LT)
-			rez = (rez < numptr_val);
-		else if (op == TOK_LE)
-			rez = (rez <= numptr_val);
-		else if (op == TOK_MUL || op == TOK_MUL_ASSIGN)
-			rez *= numptr_val;
-		else if (op == TOK_ADD || op == TOK_PLUS_ASSIGN)
-			rez += numptr_val;
-		else if (op == TOK_SUB || op == TOK_MINUS_ASSIGN)
-			rez -= numptr_val;
-		else if (op == TOK_ASSIGN || op == TOK_COMMA)
-			rez = numptr_val;
-		else if (op == TOK_CONDITIONAL_SEP) {
-			if (numptr_m1 == numstack) {
-				/* protect $((expr : expr)) without "expr ? " */
-				goto err;
-			}
-			numptr_m1->contidional_second_val_initialized = op;
-			numptr_m1->contidional_second_val = numptr_val;
-		} else if (op == TOK_CONDITIONAL) {
-			rez = rez ?
-				numptr_val : numptr_m1->contidional_second_val;
-		} else if (op == TOK_EXPONENT) {
-			if (numptr_val < 0)
-				return -3;      /* exponent less than 0 */
-			else {
-				arith_t c = 1;
-
-				if (numptr_val)
-					while (numptr_val--)
-						c *= rez;
-				rez = c;
-			}
-		} else if (numptr_val==0)          /* zero divisor check */
-			return -2;
-		else if (op == TOK_DIV || op == TOK_DIV_ASSIGN)
-			rez /= numptr_val;
-		else if (op == TOK_REM || op == TOK_REM_ASSIGN)
-			rez %= numptr_val;
-	}
-	if (tok_have_assign(op)) {
-		char buf[sizeof(arith_t_type)*3 + 2];
-
-		if (numptr_m1->var == NULL) {
-			/* Hmm, 1=2 ? */
-			goto err;
-		}
-		/* save to shell variable */
-#if ENABLE_ASH_MATH_SUPPORT_64
-		snprintf(buf, sizeof(buf), "%lld", (arith_t_type) rez);
-#else
-		snprintf(buf, sizeof(buf), "%ld", (arith_t_type) rez);
-#endif
-		setvar(numptr_m1->var, buf, 0);
-		/* after saving, make previous value for v++ or v-- */
-		if (op == TOK_POST_INC)
-			rez--;
-		else if (op == TOK_POST_DEC)
-			rez++;
-	}
-	numptr_m1->val = rez;
-	/* protect geting var value, is number now */
-	numptr_m1->var = NULL;
-	return 0;
- err:
-	return -1;
-}
-
-/* longest must be first */
-static const char op_tokens[] ALIGN1 = {
-	'<','<','=',0, TOK_LSHIFT_ASSIGN,
-	'>','>','=',0, TOK_RSHIFT_ASSIGN,
-	'<','<',    0, TOK_LSHIFT,
-	'>','>',    0, TOK_RSHIFT,
-	'|','|',    0, TOK_OR,
-	'&','&',    0, TOK_AND,
-	'!','=',    0, TOK_NE,
-	'<','=',    0, TOK_LE,
-	'>','=',    0, TOK_GE,
-	'=','=',    0, TOK_EQ,
-	'|','=',    0, TOK_OR_ASSIGN,
-	'&','=',    0, TOK_AND_ASSIGN,
-	'*','=',    0, TOK_MUL_ASSIGN,
-	'/','=',    0, TOK_DIV_ASSIGN,
-	'%','=',    0, TOK_REM_ASSIGN,
-	'+','=',    0, TOK_PLUS_ASSIGN,
-	'-','=',    0, TOK_MINUS_ASSIGN,
-	'-','-',    0, TOK_POST_DEC,
-	'^','=',    0, TOK_XOR_ASSIGN,
-	'+','+',    0, TOK_POST_INC,
-	'*','*',    0, TOK_EXPONENT,
-	'!',        0, TOK_NOT,
-	'<',        0, TOK_LT,
-	'>',        0, TOK_GT,
-	'=',        0, TOK_ASSIGN,
-	'|',        0, TOK_BOR,
-	'&',        0, TOK_BAND,
-	'*',        0, TOK_MUL,
-	'/',        0, TOK_DIV,
-	'%',        0, TOK_REM,
-	'+',        0, TOK_ADD,
-	'-',        0, TOK_SUB,
-	'^',        0, TOK_BXOR,
-	/* uniq */
-	'~',        0, TOK_BNOT,
-	',',        0, TOK_COMMA,
-	'?',        0, TOK_CONDITIONAL,
-	':',        0, TOK_CONDITIONAL_SEP,
-	')',        0, TOK_RPAREN,
-	'(',        0, TOK_LPAREN,
-	0
-};
-/* ptr to ")" */
-#define endexpression (&op_tokens[sizeof(op_tokens)-7])
-
-static arith_t
-arith(const char *expr, int *perrcode)
-{
-	char arithval; /* Current character under analysis */
-	operator lasttok, op;
-	operator prec;
-	operator *stack, *stackptr;
-	const char *p = endexpression;
-	int errcode;
-	v_n_t *numstack, *numstackptr;
-	unsigned datasizes = strlen(expr) + 2;
-
-	/* Stack of integers */
-	/* The proof that there can be no more than strlen(startbuf)/2+1 integers
-	 * in any given correct or incorrect expression is left as an exercise to
-	 * the reader. */
-	numstackptr = numstack = alloca((datasizes / 2) * sizeof(numstack[0]));
-	/* Stack of operator tokens */
-	stackptr = stack = alloca(datasizes * sizeof(stack[0]));
-
-	*stackptr++ = lasttok = TOK_LPAREN;     /* start off with a left paren */
-	*perrcode = errcode = 0;
-
-	while (1) {
-		arithval = *expr;
-		if (arithval == 0) {
-			if (p == endexpression) {
-				/* Null expression. */
-				return 0;
-			}
-
-			/* This is only reached after all tokens have been extracted from the
-			 * input stream. If there are still tokens on the operator stack, they
-			 * are to be applied in order. At the end, there should be a final
-			 * result on the integer stack */
-
-			if (expr != endexpression + 1) {
-				/* If we haven't done so already, */
-				/* append a closing right paren */
-				expr = endexpression;
-				/* and let the loop process it. */
-				continue;
-			}
-			/* At this point, we're done with the expression. */
-			if (numstackptr != numstack+1) {
-				/* ... but if there isn't, it's bad */
- err:
-				*perrcode = -1;
-				return *perrcode;
-			}
-			if (numstack->var) {
-				/* expression is $((var)) only, lookup now */
-				errcode = arith_lookup_val(numstack);
-			}
- ret:
-			*perrcode = errcode;
-			return numstack->val;
-		}
-
-		/* Continue processing the expression. */
-		if (arith_isspace(arithval)) {
-			/* Skip whitespace */
-			goto prologue;
-		}
-		p = endofname(expr);
-		if (p != expr) {
-			size_t var_name_size = (p-expr) + 1;  /* trailing zero */
-
-			numstackptr->var = alloca(var_name_size);
-			safe_strncpy(numstackptr->var, expr, var_name_size);
-			expr = p;
- num:
-			numstackptr->contidional_second_val_initialized = 0;
-			numstackptr++;
-			lasttok = TOK_NUM;
-			continue;
-		}
-		if (isdigit(arithval)) {
-			numstackptr->var = NULL;
-#if ENABLE_ASH_MATH_SUPPORT_64
-			numstackptr->val = strtoll(expr, (char **) &expr, 0);
-#else
-			numstackptr->val = strtol(expr, (char **) &expr, 0);
-#endif
-			goto num;
-		}
-		for (p = op_tokens; ; p++) {
-			const char *o;
-
-			if (*p == 0) {
-				/* strange operator not found */
-				goto err;
-			}
-			for (o = expr; *p && *o == *p; p++)
-				o++;
-			if (!*p) {
-				/* found */
-				expr = o - 1;
-				break;
-			}
-			/* skip tail uncompared token */
-			while (*p)
-				p++;
-			/* skip zero delim */
-			p++;
-		}
-		op = p[1];
-
-		/* post grammar: a++ reduce to num */
-		if (lasttok == TOK_POST_INC || lasttok == TOK_POST_DEC)
-			lasttok = TOK_NUM;
-
-		/* Plus and minus are binary (not unary) _only_ if the last
-		 * token was as number, or a right paren (which pretends to be
-		 * a number, since it evaluates to one). Think about it.
-		 * It makes sense. */
-		if (lasttok != TOK_NUM) {
-			switch (op) {
-			case TOK_ADD:
-				op = TOK_UPLUS;
-				break;
-			case TOK_SUB:
-				op = TOK_UMINUS;
-				break;
-			case TOK_POST_INC:
-				op = TOK_PRE_INC;
-				break;
-			case TOK_POST_DEC:
-				op = TOK_PRE_DEC;
-				break;
-			}
-		}
-		/* We don't want a unary operator to cause recursive descent on the
-		 * stack, because there can be many in a row and it could cause an
-		 * operator to be evaluated before its argument is pushed onto the
-		 * integer stack. */
-		/* But for binary operators, "apply" everything on the operator
-		 * stack until we find an operator with a lesser priority than the
-		 * one we have just extracted. */
-		/* Left paren is given the lowest priority so it will never be
-		 * "applied" in this way.
-		 * if associativity is right and priority eq, applied also skip
-		 */
-		prec = PREC(op);
-		if ((prec > 0 && prec < UNARYPREC) || prec == SPEC_PREC) {
-			/* not left paren or unary */
-			if (lasttok != TOK_NUM) {
-				/* binary op must be preceded by a num */
-				goto err;
-			}
-			while (stackptr != stack) {
-				if (op == TOK_RPAREN) {
-					/* The algorithm employed here is simple: while we don't
-					 * hit an open paren nor the bottom of the stack, pop
-					 * tokens and apply them */
-					if (stackptr[-1] == TOK_LPAREN) {
-						--stackptr;
-						/* Any operator directly after a */
-						lasttok = TOK_NUM;
-						/* close paren should consider itself binary */
-						goto prologue;
-					}
-				} else {
-					operator prev_prec = PREC(stackptr[-1]);
-
-					convert_prec_is_assing(prec);
-					convert_prec_is_assing(prev_prec);
-					if (prev_prec < prec)
-						break;
-					/* check right assoc */
-					if (prev_prec == prec && is_right_associativity(prec))
-						break;
-				}
-				errcode = arith_apply(*--stackptr, numstack, &numstackptr);
-				if (errcode) goto ret;
-			}
-			if (op == TOK_RPAREN) {
-				goto err;
-			}
-		}
-
-		/* Push this operator to the stack and remember it. */
-		*stackptr++ = lasttok = op;
- prologue:
-		++expr;
-	} /* while */
-}
-#endif /* ASH_MATH_SUPPORT */
-
-
 /* ============ main() and helpers */
 
 /*
@@ -13763,7 +13109,7 @@ extern int etext();
 int ash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int ash_main(int argc UNUSED_PARAM, char **argv)
 {
-	char *shinit;
+	const char *shinit;
 	volatile smallint state;
 	struct jmploc jmploc;
 	struct stackmark smark;
@@ -13868,7 +13214,8 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
 	if (minusc) {
 		/* evalstring pushes parsefile stack.
 		 * Ensure we don't falsely claim that 0 (stdin)
-		 * is one of stacked source fds */
+		 * is one of stacked source fds.
+		 * Testcase: ash -c 'exec 1>&0' must not complain. */
 		if (!sflag)
 			g_parsefile->fd = -1;
 		evalstring(minusc, 0);