Stage28: allow NUL in warning messages

13 files changed, 192 insertions, 93 deletions

diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index eb2a6673..0f5c53ef 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -43,7 +43,7 @@ This manual is for @acronym{GNU} M4 (version @value{VERSION}, @value{UPDATED}),
 a package containing an implementation of the m4 macro language.
 
 Copyright @copyright{} 1989, 1990, 1991, 1992, 1993, 1994, 2004, 2005,
-2006, 2007, 2008 Free Software Foundation, Inc.
+2006, 2007, 2008, 2009 Free Software Foundation, Inc.
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document
@@ -935,14 +935,16 @@ exception of the @sc{nul} character (the zero byte @samp{'\0'}).
 
 @comment xout: null.out
 @comment xerr: null.err
+@comment status: 1
 @example
 define(`m4exit')include(`null.m4')dnl
 @end example
 
-@comment status: 2
+@comment status: 1
 @example
 include(`null.m4')
 @result{}# This file tests m4 behavior on NUL bytes.
+@error{}m4:examples/null.m4:5: Warning: m4exit: non-numeric argument `2\0002'
 @end example
 @end ignore
 
@@ -6087,10 +6089,10 @@ eval(`2 = 2')
 @error{}m4:stdin:1: Warning: eval: recommend ==, not =, for equality
 @result{}1
 eval(`++0')
-@error{}m4:stdin:2: eval: invalid operator: ++0
+@error{}m4:stdin:2: eval: invalid operator: `++0'
 @result{}
 eval(`0 |= 1')
-@error{}m4:stdin:3: eval: invalid operator: 0 |= 1
+@error{}m4:stdin:3: eval: invalid operator: `0 |= 1'
 @result{}
 @end example
 
@@ -6133,12 +6135,12 @@ eval(`+ + - ~ ! ~ 0')
 eval(`2 || 1 / 0')
 @result{}1
 eval(`0 || 1 / 0')
-@error{}m4:stdin:9: Warning: eval: divide by zero: 0 || 1 / 0
+@error{}m4:stdin:9: Warning: eval: divide by zero: `0 || 1 / 0'
 @result{}
 eval(`0 && 1 % 0')
 @result{}0
 eval(`2 && 1 % 0')
-@error{}m4:stdin:11: Warning: eval: modulo by zero: 2 && 1 % 0
+@error{}m4:stdin:11: Warning: eval: modulo by zero: `2 && 1 % 0'
 @result{}
 @end example
 
@@ -6159,9 +6161,9 @@ eval(`2 ** 0')
 @result{}1
 eval(`0 ** 0')
 @result{}
-@error{}m4:stdin:5: Warning: eval: divide by zero: 0 ** 0
+@error{}m4:stdin:5: Warning: eval: divide by zero: `0 ** 0'
 eval(`4 ** -2')
-@error{}m4:stdin:6: Warning: eval: negative exponent: 4 ** -2
+@error{}m4:stdin:6: Warning: eval: negative exponent: `4 ** -2'
 @result{}
 @end example
 
@@ -6206,7 +6208,7 @@ square(square(`5')` + 1')
 define(`foo', `666')
 @result{}
 eval(`foo / 6')
-@error{}m4:stdin:11: Warning: eval: bad expression: foo / 6
+@error{}m4:stdin:11: Warning: eval: bad expression: `foo / 6'
 @result{}
 eval(foo / 6)
 @result{}111
@@ -6659,10 +6661,12 @@ define(`foo', `errprint(`oops')')
 syscmd(`rm -f foo-??????')sysval
 @result{}0
 define(`file1', maketemp(`foo-XXXXXX'))dnl
+@error{}m4:stdin:3: Warning: maketemp: recommend using mkstemp instead
 ifelse(esyscmd(`echo \` foo-?????? \''), ` foo-?????? ',
        `no file', `created')
 @result{}created
 define(`file2', maketemp(`foo-XX'))dnl
+@error{}m4:stdin:6: Warning: maketemp: recommend using mkstemp instead
 define(`file3', mkstemp(`foo-XXXXXX'))dnl
 ifelse(len(defn(`file1')), len(defn(`file2')),
        `same length', `different')
@@ -7082,6 +7086,20 @@ divert(1)undivert(null.out)' | ]__program__[ -F in.m4f \
 ])dnl
 @error{}divnum #-- 3 0
 @end example
+
+@c Do we reject unexpected NUL bytes?
+
+@example
+ifdef(`__unix__', ,
+      `errprint(` skipping: syscmd does not have unix semantics
+')m4exit(`77')')dnl
+changequote(`[', `]')dnl
+syscmd([printf '#bogus\nV1\nF3,4\nlenlen\0\n' > in.m4f \
+     && ]__program__[ -R in.m4f \
+     && rm in.m4f])sysval
+@error{}m4: ill-formed frozen file, invalid builtin `len\0' encountered
+@result{}1
+@end example
 @end ignore
 
 When an @code{m4} run is to be frozen, the automatic undiversion
@@ -7615,7 +7633,7 @@ forloop(`', `1', `2', ` odd iterator name')
 forloop(`i', `5 + 5', `0xc', ` 0x`'eval(i, `16')')
 @result{} 0xa 0xb 0xc
 forloop(`i', `a', `b', `non-numeric bounds')
-@error{}m4:stdin:6: Warning: eval: bad expression (bad input): (b) >= (a)
+@error{}m4:stdin:6: Warning: eval: bad input in expression: `(b) >= (a)'
 @result{}
 @end example
 
diff --git a/examples/null.err b/examples/null.err
index 977b3b7c..b0858b3e 100644
--- a/examples/null.err
+++ b/examples/null.err
diff --git a/examples/null.m4 b/examples/null.m4
index e60aec5a..3dc8d16c 100644
--- a/examples/null.m4
+++ b/examples/null.m4
diff --git a/examples/null.out b/examples/null.out
index c2c1cb90..0dfbfdb4 100644
--- a/examples/null.out
+++ b/examples/null.out
diff --git a/m4/gnulib-cache.m4 b/m4/gnulib-cache.m4
index 5a1cd9b4..eaa67a2f 100644
--- a/m4/gnulib-cache.m4
+++ b/m4/gnulib-cache.m4
@@ -1,4 +1,4 @@
-# Copyright (C) 2002-2008 Free Software Foundation, Inc.
+# Copyright (C) 2002-2009 Free Software Foundation, Inc.
 #
 # This file is free software, distributed under the terms of the GNU
 # General Public License.  As a special exception to the GNU General
diff --git a/src/builtin.c b/src/builtin.c
index beb2a04a..0c9b9056 100644
--- a/src/builtin.c
+++ b/src/builtin.c
@@ -1,7 +1,7 @@
 /* GNU m4 -- A simple macro processor
 
-   Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2000, 2004, 2006, 2007,
-   2008 Free Software Foundation, Inc.
+   Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2000, 2004, 2006,
+   2007, 2008, 2009 Free Software Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -562,18 +562,18 @@ bad_argc (const call_info *name, int argc, unsigned int min, unsigned int max)
   return false;
 }
 
-/*-------------------------------------------------------------------.
-| The function numeric_arg () converts ARG to an int pointed to by   |
-| VALUEP.  If the conversion fails, print error message on behalf of |
-| NAME.  Return true iff conversion succeeds.                        |
-`-------------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| The function numeric_arg () converts ARG of length LEN to an int  |
+| pointed to by VALUEP.  If the conversion fails, print error       |
+| message on behalf of NAME.  Return true iff conversion succeeds.  |
+`------------------------------------------------------------------*/
 
 static bool
-numeric_arg (const call_info *name, const char *arg, int *valuep)
+numeric_arg (const call_info *name, const char *arg, size_t len, int *valuep)
 {
   char *endp;
 
-  if (*arg == '\0')
+  if (!len)
     {
       *valuep = 0;
       m4_warn (0, name, _("empty string treated as 0"));
@@ -582,9 +582,10 @@ numeric_arg (const call_info *name, const char *arg, int *valuep)
     {
       errno = 0;
       *valuep = strtol (arg, &endp, 10);
-      if (*endp != '\0')
+      if (endp - arg != len)
 	{
-	  m4_warn (0, name, _("non-numeric argument `%s'"), arg);
+	  m4_warn (0, name, _("non-numeric argument %s"),
+		   quotearg_style_mem (locale_quoting_style, arg, len));
 	  return false;
 	}
       if (isspace (to_uchar (*arg)))
@@ -1070,8 +1071,9 @@ m4_defn (struct obstack *obs, int argc, macro_arguments *argv)
 	  b = SYMBOL_FUNC (s);
 	  if (b == m4_placeholder)
 	    m4_warn (0, me,
-		     _("builtin `%s' requested by frozen file not found"),
-		     ARG (i));
+		     _("builtin %s requested by frozen file not found"),
+		     quotearg_style_mem (locale_quoting_style, ARG (i),
+					 ARG_LEN (i)));
 	  else
 	    push_macro (obs, b);
 	  break;
@@ -1123,7 +1125,14 @@ static int sysval;
 static void
 m4_syscmd (struct obstack *obs, int argc, macro_arguments *argv)
 {
-  if (bad_argc (arg_info (argv), argc, 1, 1))
+  const call_info *me = arg_info (argv);
+  const char *cmd = ARG (1);
+  size_t len = ARG_LEN (1);
+
+  if (strlen (cmd) != len)
+    m4_warn (0, me, _("argument %s truncated"),
+	     quotearg_style_mem (locale_quoting_style, cmd, len));
+  if (bad_argc (me, argc, 1, 1) || !*cmd)
     {
       /* The empty command is successful.  */
       sysval = 0;
@@ -1131,7 +1140,7 @@ m4_syscmd (struct obstack *obs, int argc, macro_arguments *argv)
     }
 
   debug_flush_files ();
-  sysval = system (ARG (1));
+  sysval = system (cmd);
 #if FUNC_SYSTEM_BROKEN
   /* OS/2 has a buggy system() that returns exit status in the lowest eight
      bits, although pclose() and WEXITSTATUS are defined to return exit
@@ -1148,10 +1157,15 @@ static void
 m4_esyscmd (struct obstack *obs, int argc, macro_arguments *argv)
 {
   const call_info *me = arg_info (argv);
+  const char *cmd = ARG (1);
+  size_t len = ARG_LEN (1);
   FILE *pin;
   int ch;
 
-  if (bad_argc (me, argc, 1, 1))
+  if (strlen (cmd) != len)
+    m4_warn (0, me, _("argument %s truncated"),
+	     quotearg_style_mem (locale_quoting_style, cmd, len));
+  if (bad_argc (me, argc, 1, 1) || !*cmd)
     {
       /* The empty command is successful.  */
       sysval = 0;
@@ -1160,10 +1174,11 @@ m4_esyscmd (struct obstack *obs, int argc, macro_arguments *argv)
 
   debug_flush_files ();
   errno = 0;
-  pin = popen (ARG (1), "r");
+  pin = popen (cmd, "r");
   if (pin == NULL)
     {
-      m4_warn (errno, me, _("cannot open pipe to command `%s'"), ARG (1));
+      m4_warn (errno, me, _("cannot open pipe to command %s"),
+	       quotearg_style (locale_quoting_style, cmd));
       sysval = -1;
     }
   else
@@ -1200,7 +1215,7 @@ m4_eval (struct obstack *obs, int argc, macro_arguments *argv)
   if (bad_argc (me, argc, 1, 3))
     return;
 
-  if (!arg_empty (argv, 2) && !numeric_arg (me, ARG (2), &radix))
+  if (!arg_empty (argv, 2) && !numeric_arg (me, ARG (2), ARG_LEN (2), &radix))
     return;
 
   if (radix < 1 || radix > 36)
@@ -1209,7 +1224,7 @@ m4_eval (struct obstack *obs, int argc, macro_arguments *argv)
       return;
     }
 
-  if (argc >= 4 && !numeric_arg (me, ARG (3), &min))
+  if (argc >= 4 && !numeric_arg (me, ARG (3), ARG_LEN (3), &min))
     return;
   if (min < 0)
     {
@@ -1264,7 +1279,7 @@ m4_incr (struct obstack *obs, int argc, macro_arguments *argv)
   if (bad_argc (me, argc, 1, 1))
     return;
 
-  if (!numeric_arg (me, ARG (1), &value))
+  if (!numeric_arg (me, ARG (1), ARG_LEN (1), &value))
     return;
 
   shipout_int (obs, value + 1);
@@ -1279,7 +1294,7 @@ m4_decr (struct obstack *obs, int argc, macro_arguments *argv)
   if (bad_argc (me, argc, 1, 1))
     return;
 
-  if (!numeric_arg (me, ARG (1), &value))
+  if (!numeric_arg (me, ARG (1), ARG_LEN (1), &value))
     return;
 
   shipout_int (obs, value - 1);
@@ -1300,7 +1315,7 @@ m4_divert (struct obstack *obs, int argc, macro_arguments *argv)
   int i = 0;
 
   bad_argc (me, argc, 0, 1);
-  if (argc >= 2 && !numeric_arg (me, ARG (1), &i))
+  if (argc >= 2 && !numeric_arg (me, ARG (1), ARG_LEN (1), &i))
     return;
 
   make_diversion (i);
@@ -1339,11 +1354,16 @@ m4_undivert (struct obstack *obs, int argc, macro_arguments *argv)
     for (i = 1; i < argc; i++)
       {
 	const char *str = ARG (i);
+	size_t len = ARG_LEN (i);
 	file = strtol (str, &endp, 10);
-	if (*endp == '\0' && !isspace (to_uchar (*str)))
+	if (endp - str == len && !isspace (to_uchar (*str)))
 	  insert_diversion (file);
 	else if (no_gnu_extensions)
-	  m4_warn (0, me, _("non-numeric argument `%s'"), str);
+	  m4_warn (0, me, _("non-numeric argument %s"),
+		   quotearg_style_mem (locale_quoting_style, str, len));
+	else if (strlen (str) != len)
+	  m4_warn (0, me, _("invalid file name %s"),
+		   quotearg_style_mem (locale_quoting_style, str, len));
 	else
 	  {
 	    fp = m4_path_search (str, NULL);
@@ -1351,10 +1371,12 @@ m4_undivert (struct obstack *obs, int argc, macro_arguments *argv)
 	      {
 		insert_file (fp);
 		if (fclose (fp) == EOF)
-		  m4_warn (errno, me, _("error undiverting `%s'"), str);
+		  m4_warn (errno, me, _("error undiverting %s"),
+			   quotearg_style (locale_quoting_style, str));
 	      }
 	    else
-	      m4_warn (errno, me, _("cannot undivert `%s'"), str);
+	      m4_warn (errno, me, _("cannot undivert %s"),
+		       quotearg_style (locale_quoting_style, str));
 	  }
       }
 }
@@ -1453,15 +1475,23 @@ include (int argc, macro_arguments *argv, bool silent)
   const call_info *me = arg_info (argv);
   FILE *fp;
   char *name;
+  const char *arg;
+  size_t len;
 
   if (bad_argc (me, argc, 1, 1))
     return;
 
-  fp = m4_path_search (ARG (1), &name);
+  arg = ARG (1);
+  len = ARG_LEN (1);
+  if (strlen (arg) != len)
+    m4_warn (0, me, _("argument %s truncated"),
+	     quotearg_style_mem (locale_quoting_style, arg, len));
+  fp = m4_path_search (arg, &name);
   if (fp == NULL)
     {
       if (!silent)
-	m4_error (0, errno, me, _("cannot open `%s'"), ARG (1));
+	m4_error (0, errno, me, _("cannot open %s"),
+		  quotearg_style (locale_quoting_style, arg));
       return;
     }
 
@@ -1511,6 +1541,12 @@ mkstemp_helper (struct obstack *obs, const call_info *me, const char *pattern,
      user forgot to supply them.  Output must be quoted if
      successful.  */
   obstack_grow (obs, curr_quote.str1, curr_quote.len1);
+  if (strlen (pattern) < len)
+    {
+      m4_warn (0, me, _("argument %s truncated"),
+	       quotearg_style_mem (locale_quoting_style, pattern, len));
+      len = strlen (pattern);
+    }
   obstack_grow (obs, pattern, len);
   for (i = 0; len > 0 && i < 6; i++)
     if (pattern[--len] != 'X')
@@ -1522,7 +1558,8 @@ mkstemp_helper (struct obstack *obs, const call_info *me, const char *pattern,
   fd = mkstemp (name);
   if (fd < 0)
     {
-      m4_warn (errno, me, _("cannot create tempfile `%s'"), pattern);
+      m4_warn (errno, me, _("cannot create file from template %s"),
+	       quotearg_style (locale_quoting_style, pattern));
       obstack_free (obs, obstack_finish (obs));
     }
   else
@@ -1541,6 +1578,7 @@ m4_maketemp (struct obstack *obs, int argc, macro_arguments *argv)
 
   if (bad_argc (me, argc, 1, 1))
     return;
+  m4_warn (0, me, _("recommend using mkstemp instead"));
   if (no_gnu_extensions)
     {
       /* POSIX states "any trailing 'X' characters [are] replaced with
@@ -1562,7 +1600,6 @@ m4_maketemp (struct obstack *obs, int argc, macro_arguments *argv)
 				       (unsigned long) getpid ());
       char *pid = (char *) obstack_copy0 (scratch, "", 0);
 
-      m4_warn (0, me, _("recommend using mkstemp instead"));
       for (i = len; i > 1; i--)
 	if (str[i - 1] != 'X')
 	  break;
@@ -1648,7 +1685,7 @@ m4_m4exit (struct obstack *obs, int argc, macro_arguments *argv)
 
   /* Warn on bad arguments, but still exit.  */
   bad_argc (me, argc, 0, 1);
-  if (argc >= 2 && !numeric_arg (me, ARG (1), &exit_code))
+  if (argc >= 2 && !numeric_arg (me, ARG (1), ARG_LEN (1), &exit_code))
     exit_code = EXIT_FAILURE;
   if (exit_code < 0 || exit_code > 255)
     {
@@ -1763,6 +1800,7 @@ m4_debugmode (struct obstack *obs, int argc, macro_arguments *argv)
 {
   const call_info *me = arg_info (argv);
   const char *str = ARG (1);
+  size_t len = ARG_LEN (1);
   int new_debug_level;
   int change_flag;
 
@@ -1775,16 +1813,17 @@ m4_debugmode (struct obstack *obs, int argc, macro_arguments *argv)
       if (*str == '+' || *str == '-')
 	{
 	  change_flag = *str;
-	  new_debug_level = debug_decode (str + 1);
+	  new_debug_level = debug_decode (str + 1, len - 1);
 	}
       else
 	{
 	  change_flag = 0;
-	  new_debug_level = debug_decode (str);
+	  new_debug_level = debug_decode (str, len);
 	}
 
       if (new_debug_level < 0)
-	m4_warn (0, me, _("bad debug flags: `%s'"), str);
+	m4_warn (0, me, _("bad debug flags: %s"),
+		 quotearg_style_mem (locale_quoting_style, str, len));
       else
 	{
 	  switch (change_flag)
@@ -1819,8 +1858,17 @@ m4_debugfile (struct obstack *obs, int argc, macro_arguments *argv)
 
   if (argc == 1)
     debug_set_output (me, NULL);
-  else if (!debug_set_output (me, ARG (1)))
-    m4_warn (errno, me, _("cannot set error file: `%s'"), ARG (1));
+  else
+    {
+      const char *str = ARG (1);
+      size_t len = ARG_LEN (1);
+      if (strlen (str) < len)
+	m4_warn (0, me, _("argument %s truncated"),
+		 quotearg_style_mem (locale_quoting_style, str, len));
+      if (!debug_set_output (me, str))
+	m4_warn (errno, me, _("cannot set debug file %s"),
+		 quotearg_style (locale_quoting_style, str));
+    }
 }
 
 /* This section contains text processing macros: "len", "index",
@@ -1896,10 +1944,10 @@ m4_substr (struct obstack *obs, int argc, macro_arguments *argv)
     }
 
   length = avail = ARG_LEN (1);
-  if (!numeric_arg (me, ARG (2), &start))
+  if (!numeric_arg (me, ARG (2), ARG_LEN (2), &start))
     return;
 
-  if (argc >= 4 && !numeric_arg (me, ARG (3), &length))
+  if (argc >= 4 && !numeric_arg (me, ARG (3), ARG_LEN (3), &length))
     return;
 
   if (start < 0 || length <= 0 || start >= avail)
@@ -2362,8 +2410,8 @@ m4_patsubst (struct obstack *obs, int argc, macro_arguments *argv)
 void
 m4_placeholder (struct obstack *obs, int argc, macro_arguments *argv)
 {
-  m4_warn (0, NULL, _("builtin `%s' requested by frozen file not found"),
-	   ARG (0));
+  m4_warn (0, NULL, _("builtin %s requested by frozen file not found"),
+	   quotearg_style_mem (locale_quoting_style, ARG (0), ARG_LEN (0)));
 }
 
 /*-------------------------------------------------------------------------.
diff --git a/src/debug.c b/src/debug.c
index c3f85bd6..82f0cbc8 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -43,21 +43,26 @@ debug_init (void)
   obstack_init (&trace);
 }
 
-/*-----------------------------------------------------------------.
-| Function to decode the debugging flags OPTS.  Used by main while |
-| processing option -d, and by the builtin debugmode ().	   |
-`-----------------------------------------------------------------*/
+/*-------------------------------------------------------------------.
+| Function to decode the debugging flags OPTS of length LEN.  If LEN |
+| is SIZE_MAX, use strlen (OPTS) instead.  Used by main while        |
+| processing option -d, and by the builtin debugmode.                |
+`-------------------------------------------------------------------*/
 
 int
-debug_decode (const char *opts)
+debug_decode (const char *opts, size_t len)
 {
   int level;
 
-  if (opts == NULL || *opts == '\0')
+  if (!opts)
+    opts = "";
+  if (len == SIZE_MAX)
+    len = strlen (opts);
+  if (!len)
     level = DEBUG_TRACE_DEFAULT;
   else
     {
-      for (level = 0; *opts; opts++)
+      for (level = 0; len--; opts++)
 	{
 	  switch (*opts)
 	    {
diff --git a/src/eval.c b/src/eval.c
index 1b617ed7..b72e5cd1 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -313,6 +313,8 @@ evaluate (const call_info *me, const char *expr, size_t len, int32_t *val)
 	err = EXCESS_INPUT;
     }
 
+  if (err != NO_ERROR)
+    expr = quotearg_style_mem (locale_quoting_style, expr, len);
   switch (err)
     {
       /* Cases where result is printed.  */
@@ -325,8 +327,7 @@ evaluate (const call_info *me, const char *expr, size_t len, int32_t *val)
 
       /* Cases where error makes result meaningless.  */
     case MISSING_RIGHT:
-      m4_warn (0, me, _("bad expression (missing right parenthesis): %s"),
-	       expr);
+      m4_warn (0, me, _("missing right parenthesis: %s"), expr);
       break;
 
     case SYNTAX_ERROR:
@@ -334,11 +335,11 @@ evaluate (const call_info *me, const char *expr, size_t len, int32_t *val)
       break;
 
     case UNKNOWN_INPUT:
-      m4_warn (0, me, _("bad expression (bad input): %s"), expr);
+      m4_warn (0, me, _("bad input in expression: %s"), expr);
       break;
 
     case EXCESS_INPUT:
-      m4_warn (0, me, _("bad expression (excess input): %s"), expr);
+      m4_warn (0, me, _("excess input in expression: %s"), expr);
       break;
 
     case INVALID_OPERATOR:
diff --git a/src/format.c b/src/format.c
index 8b2b11ae..09cffa3c 100644
--- a/src/format.c
+++ b/src/format.c
@@ -27,24 +27,26 @@
    same size; likewise for long and unsigned long.  We do not yet
    handle long double or long long.  */
 
-/* Parse STR as an integer, reporting warnings on behalf of ME.  */
+/* Parse STR of length LEN as an integer, reporting warnings on behalf
+   of ME.  */
 static int
-arg_int (const call_info *me, const char *str)
+arg_int (const call_info *me, const char *str, size_t len)
 {
   char *endp;
   long value;
 
   /* TODO - also allow parsing `'a' or `"a' which results in the
      numeric value of 'a', as in printf(1).  */
-  if (*str == '\0')
+  if (!len)
     {
       m4_warn (0, me, _("empty string treated as 0"));
       return 0;
     }
   errno = 0;
   value = strtol (str, &endp, 10);
-  if (*endp != '\0')
-    m4_warn (0, me, _("non-numeric argument `%s'"), str);
+  if (endp - str != len)
+    m4_warn (0, me, _("non-numeric argument %s"),
+	     quotearg_style_mem (locale_quoting_style, str, len));
   else if (isspace (to_uchar (*str)))
     m4_warn (0, me, _("leading whitespace ignored"));
   else if (errno == ERANGE || (int) value != value)
@@ -52,24 +54,26 @@ arg_int (const call_info *me, const char *str)
   return value;
 }
 
-/* Parse STR as a long, reporting warnings on behalf of ME.  */
+/* Parse STR of length LEN as a long, reporting warnings on behalf of
+   ME.  */
 static long
-arg_long (const call_info *me, const char *str)
+arg_long (const call_info *me, const char *str, size_t len)
 {
   char *endp;
   long value;
 
   /* TODO - also allow parsing `'a' or `"a' which results in the
      numeric value of 'a', as in printf(1).  */
-  if (*str == '\0')
+  if (!len)
     {
       m4_warn (0, me, _("empty string treated as 0"));
       return 0L;
     }
   errno = 0;
   value = strtol (str, &endp, 10);
-  if (*endp != '\0')
-    m4_warn (0, me, _("non-numeric argument `%s'"), str);
+  if (endp - str != len)
+    m4_warn (0, me, _("non-numeric argument %s"),
+	     quotearg_style_mem (locale_quoting_style, str, len));
   else if (isspace (to_uchar (*str)))
     m4_warn (0, me, _("leading whitespace ignored"));
   else if (errno == ERANGE)
@@ -77,22 +81,35 @@ arg_long (const call_info *me, const char *str)
   return value;
 }
 
-/* Parse STR as a double, reporting warnings on behalf of ME.  */
+/* Check STR of length LEN for embedded NUL, reporting warnings on
+   behalf of ME.  */
+static const char *
+arg_string (const call_info *me, const char *str, size_t len)
+{
+  if (strlen (str) < len)
+    m4_warn (0, me, _("argument %s truncated"),
+	     quotearg_style_mem (locale_quoting_style, str, len));
+  return str;
+}
+
+/* Parse STR of length LEN as a double, reporting warnings on behalf
+   of ME.  */
 static double
-arg_double (const call_info *me, const char *str)
+arg_double (const call_info *me, const char *str, size_t len)
 {
   char *endp;
   double value;
 
-  if (*str == '\0')
+  if (!len)
     {
       m4_warn (0, me, _("empty string treated as 0"));
       return 0.0;
     }
   errno = 0;
   value = strtod (str, &endp);
-  if (*endp != '\0')
-    m4_warn (0, me, _("non-numeric argument `%s'"), str);
+  if (endp - str != len)
+    m4_warn (0, me, _("non-numeric argument %s"),
+	     quotearg_style_mem (locale_quoting_style, str, len));
   else if (isspace (to_uchar (*str)))
     m4_warn (0, me, _("leading whitespace ignored"));
   else if (errno == ERANGE)
@@ -101,16 +118,16 @@ arg_double (const call_info *me, const char *str)
 }
 
 #define ARG_INT(i, argc, argv)						\
-  ((argc <= ++i) ? 0 : arg_int (me, ARG (i)))
+  ((argc <= ++i) ? 0 : arg_int (me, ARG (i), ARG_LEN (i)))
 
 #define ARG_LONG(i, argc, argv)						\
-  ((argc <= ++i) ? 0L : arg_long (me, ARG (i)))
+  ((argc <= ++i) ? 0L : arg_long (me, ARG (i), ARG_LEN (i)))
 
 #define ARG_STR(i, argc, argv)						\
-  ((argc <= ++i) ? "" : ARG (i))
+  ((argc <= ++i) ? "" : arg_string (me, ARG (i), ARG_LEN (i)))
 
 #define ARG_DOUBLE(i, argc, argv)					\
-  ((argc <= ++i) ? 0.0 : arg_double (me, ARG (i)))
+  ((argc <= ++i) ? 0.0 : arg_double (me, ARG (i), ARG_LEN (i)))
 
 
 /*------------------------------------------------------------------.
diff --git a/src/freeze.c b/src/freeze.c
index 5d4ac423..75e112b6 100644
--- a/src/freeze.c
+++ b/src/freeze.c
@@ -1,7 +1,7 @@
 /* GNU m4 -- A simple macro processor
 
-   Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2006, 2007, 2008
-   Free Software Foundation, Inc.
+   Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2006, 2007, 2008,
+   2009 Free Software Foundation, Inc.
 
    This file is part of GNU M4.
 
@@ -343,8 +343,13 @@ reload_frozen_state (const char *name)
 
 	    case 'F':
 
-	      /* Enter a macro having a builtin function as a definition.  */
-
+	      /* Enter a macro having a builtin function as a
+		 definition.  No builtin contains NUL in the name.  */
+	      if (strlen (string[1]) < number[1])
+		m4_error (EXIT_FAILURE, 0, NULL, _("\
+ill-formed frozen file, invalid builtin %s encountered"),
+			  quotearg_style_mem (locale_quoting_style, string[1],
+					      number[1]));
 	      bp = find_builtin_by_name (string[1]);
 	      define_builtin (string[0], number[0], bp, SYMBOL_PUSHDEF);
 	      break;
diff --git a/src/m4.c b/src/m4.c
index 6b59a8a4..23a42093 100644
--- a/src/m4.c
+++ b/src/m4.c
@@ -370,7 +370,8 @@ process_file (const char *name)
       FILE *fp = m4_path_search (name, &full_name);
       if (fp == NULL)
 	{
-	  error (0, errno, "%s", name);
+	  error (0, errno, "cannot open %s",
+		 quotearg_style (locale_quoting_style, name));
 	  /* Set the status to EXIT_FAILURE, even though we
 	     continue to process files after a missing file.  */
 	  retcode = EXIT_FAILURE;
@@ -530,10 +531,11 @@ main (int argc, char *const *argv, char *const *envp)
 #endif
 
       case 'd':
-	debug_level = debug_decode (optarg);
+	debug_level = debug_decode (optarg, SIZE_MAX);
 	if (debug_level < 0)
 	  {
-	    error (0, 0, "bad debug flags: `%s'", optarg);
+	    error (0, 0, "bad debug flags: %s",
+		   quotearg_style (locale_quoting_style, optarg));
 	    debug_level = 0;
 	  }
 	break;
@@ -584,7 +586,8 @@ main (int argc, char *const *argv, char *const *envp)
 
   /* Do the basic initializations.  */
   if (debugfile && !debug_set_output (NULL, debugfile))
-    m4_error (0, errno, NULL, _("cannot set debug file `%s'"), debugfile);
+    m4_error (0, errno, NULL, _("cannot set debug file %s"),
+	      quotearg_style (locale_quoting_style, debugfile));
 
   input_init ();
   output_init ();
@@ -602,7 +605,7 @@ main (int argc, char *const *argv, char *const *envp)
   if (interactive)
     {
       signal (SIGINT, SIG_IGN);
-      setbuf (stdout, (char *) NULL);
+      setbuf (stdout, NULL);
     }
 
   /* Handle deferred command line macro definitions.  Must come after
diff --git a/src/m4.h b/src/m4.h
index 173eecf0..1e6e7dca 100644
--- a/src/m4.h
+++ b/src/m4.h
@@ -199,7 +199,7 @@ extern FILE *debug;
 #define DEBUG_TRACE_DEFAULT 0x007
 
 void debug_init (void);
-int debug_decode (const char *);
+int debug_decode (const char *, size_t);
 void debug_flush_files (void);
 bool debug_set_output (const call_info *, const char *);
 void debug_message (const char *, ...) M4_GNUC_PRINTF (1, 2);
diff --git a/src/path.c b/src/path.c
index 998c0ed9..75c3bf4d 100644
--- a/src/path.c
+++ b/src/path.c
@@ -160,7 +160,9 @@ m4_path_search (const char *file, char **result)
       if (fp != NULL)
 	{
 	  if (debug_level & DEBUG_TRACE_PATH)
-	    debug_message ("path search for `%s' found `%s'", file, name);
+	    debug_message ("path search for %s found %s",
+			   quotearg_style (locale_quoting_style, file),
+			   quotearg_n_style (1, locale_quoting_style, name));
 	  if (set_cloexec_flag (fileno (fp), true) != 0)
 	    m4_warn (errno, NULL, _("cannot protect input file across forks"));
 	  if (result)