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-rw-r--r--posix/wordexp.c1624
1 files changed, 1507 insertions, 117 deletions
diff --git a/posix/wordexp.c b/posix/wordexp.c
index 52869fe1d3..b204f653b5 100644
--- a/posix/wordexp.c
+++ b/posix/wordexp.c
@@ -1,5 +1,7 @@
-/* Copyright (C) 1992, 1997 Free Software Foundation, Inc.
+/* POSIX.2 wordexp implementation.
+   Copyright (C) 1997 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
+   Contributed by Tim Waugh <tim@cyberelk.demon.co.uk>.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public License as
@@ -16,170 +18,1558 @@
    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
    Boston, MA 02111-1307, USA.  */
 
-#include <sys/types.h>
 #include <wordexp.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <sys/wait.h>
 #include <signal.h>
+#include <stdlib.h>
+#include <pwd.h>
+#include <sys/types.h>
+#include <string.h>
+#include <glob.h>
+#include <ctype.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <paths.h>
+#include <errno.h>
 
+#include <assert.h>
 
-/* We do word expansion with a pipe to the shell.
-   The shell command `sh [-P] [-u] -w "words ..."' expands words.
-   If -P, command substitution is an error.
-   If -u, reference to an undefined variable is an error.
-   The shell writes on its stdout:
-   	%u\0	Number of words.
-	%u\0	Number of bytes in all words together (not counting \0s).
-	word1\0
-	word2\0
-	...
-	wordN\0
+/*
+ * This is a recursive-descent-style word expansion routine.
+ */
+
+/* Some forward declarations */
+static int
+parse_dollars (char **word, size_t *word_length, const char *words,
+	       size_t *offset, int flags, wordexp_t *pwordexp);
+static int
+parse_backtick (char **word, size_t *word_length, const char *words,
+		size_t *offset, int flags, wordexp_t *pwordexp);
+
+static int
+eval_expr (char *expr, int *result);
+
+/* The w_*() unctions manipulate word lists. */
+
+static char*
+w_extend (char *word, size_t *word_length, size_t by)
+{
+  /* Extend the allocated size of word by 'by' characters
+   * (from *word_length).
    */
+  char*	newword;
+  size_t new_length;
 
-#define	SHELL_PATH	"/bin/sh"
-#define	SHELL_NAME	"sh"
+  if (word == NULL)
+    *word_length = 0;
 
+  new_length = *word_length + by;
+  newword = realloc (word, 1 + new_length);
+  if (newword != NULL)
+    {
+      *word_length = new_length;
 
-int
-wordexp (string, pwordexp, flags)
-     const char *string;
-     wordexp_t *pwordexp;
-     int flags;
+      newword[*word_length] = 0;
+    }
+  return newword;
+}
+
+static char*
+w_addstr (char *word, size_t *word_length, const char *str)
+{
+  /* Add a string to 'word', allocating room for it.
+   */
+  char*	newword;
+  size_t new_length;
+
+  if (word == NULL)
+    *word_length = '\0';
+
+  new_length = *word_length + strlen (str);
+  newword = realloc (word, 1 + new_length);
+  if (newword != NULL)
+    {
+      strcpy (&newword[*word_length], str);
+      *word_length = new_length;
+    }
+  return newword;
+}
+
+static inline char*
+w_addchar (char *word, size_t *word_length, char ch)
+{
+  /* Add a character to 'word', allocating room for it.
+   */
+  char*	newword = w_extend (word, word_length, 1);
+
+  if (newword != NULL)
+    newword[*word_length - 1] = ch;
+  return newword;
+}
+
+static int
+w_addword (wordexp_t *pwordexp, char *word)
+{
+  /* Add a word to the wordlist */
+  size_t num_p;
+
+  num_p = 2 + pwordexp->we_wordc + pwordexp->we_offs;
+  pwordexp->we_wordv = realloc (pwordexp->we_wordv, sizeof (char *) * num_p);
+  if (pwordexp->we_wordv != NULL)
+    {
+      pwordexp->we_wordv[pwordexp->we_wordc++] = word;
+      pwordexp->we_wordv[pwordexp->we_wordc] = NULL;
+      return 0;
+    }
+
+  return WRDE_NOSPACE;
+}
+
+/* The parse_*() functions should leave *offset being the offset in 'words'
+ * to the last character processed.
+ */
+
+static int
+parse_backslash (char **word, size_t *word_length, const char *words,
+		 size_t *offset)
+{
+  /* We are poised _at_ a backslash, not in quotes */
+
+  switch (words[1 + *offset])
+    {
+    case 0:
+      /* Backslash is last character of input words */
+      return WRDE_SYNTAX;
+
+    case '\n':
+      ++(*offset);
+      break;
+
+    default:
+      *word = w_addchar (*word, word_length, words[1 + *offset]);
+      if (*word == NULL)
+	return WRDE_NOSPACE;
+
+      ++(*offset);
+      break;
+    }
+
+  return 0;
+}
+
+static int
+parse_qtd_backslash (char **word, size_t *word_length, const char *words,
+		     size_t *offset)
+{
+  /* We are poised _at_ a backslash, inside quotes */
+
+  switch (words[1 + *offset])
+    {
+    case 0:
+      /* Backslash is last character of input words */
+      return WRDE_SYNTAX;
+
+    case '\n':
+      ++(*offset);
+      break;
+
+    case '$':
+    case '`':
+    case '"':
+    case '\\':
+      *word = w_addchar (*word, word_length, words[1 + *offset]);
+      if (*word == NULL)
+	return WRDE_NOSPACE;
+
+      (*offset)++;
+      break;
+
+    default:
+      *word = w_extend (*word, word_length, 2);
+      if (*word == NULL)
+	return WRDE_NOSPACE;
+
+      (*word)[*word_length - 1] = words[1 + *offset];
+      (*word)[*word_length - 2] = words[*offset];
+      (*offset)++;
+      break;
+    }
+
+  return 0;
+}
+
+static int
+parse_tilde (char **word, size_t *word_length, const char *words,
+	     size_t *offset, size_t wordc)
+{
+  /* We are poised _at_ a tilde */
+  int i;
+
+  if (*word_length != 0)
+    {
+      if (!((*word)[*word_length - 1] == '=' && wordc == 0))
+	{
+	  if (!((*word)[*word_length - 1] == ':' &&
+		strchr(*word, '=') && wordc == 0))
+	    {
+	      *word = w_addchar (*word, word_length, '~');
+	      return *word ? 0 : WRDE_NOSPACE;
+	    }
+	}
+    }
+
+  for (i = 1 + *offset; words[i]; i++)
+    {
+      if (words[i] == ':' || words[i] == '/' || words[i] == ' ' ||
+	 words[i] == '\t' || words[i] == 0 )
+	break;
+
+      if (words[i] == '\\')
+	{
+	  *word = w_addchar (*word, word_length, '~');
+	  return *word ? 0 : WRDE_NOSPACE;
+	}
+    }
+
+  if (i == 1 + *offset)
+    {
+      /* Tilde appears on its own */
+      uid_t uid;
+      struct passwd pwd, *tpwd;
+      int buflen = 1000;
+      char* buffer = __alloca (buflen);
+      int result;
+
+      uid = getuid ();
+
+      while ((result = __getpwuid_r (uid, pwd, buffer, buflen, &tpwd)) != 0
+	     && errno == ERANGE)
+	{
+	  buflen += 1000;
+	  buffer = __alloca (buflen);
+	}
+
+      if (result == 0 && pwd.pw_dir != NULL)
+	{
+	  *word = w_addstr (*word, word_length, pwd.pw_dir);
+	  if (*word == NULL)
+	    return WRDE_NOSPACE;
+	}
+      else
+	{
+	  *word = w_addchar (*word, word_length, '~');
+	  if (*word == NULL)
+	    return WRDE_NOSPACE;
+	}
+    }
+  else
+    {
+      /* Look up user name in database to get home directory */
+      uid_t uid;
+      char *user = strndup (&words[1 + *offset], i - *offset);
+      struct passwd pwd, *tpwd;
+      int buflen = 1000;
+      char* buffer = __alloca (buflen);
+      int result;
+
+      while ((result = __getpwnam_r (uid, pwd, buffer, buflen, &tpwd)) != 0
+	     && errno == ERANGE)
+	{
+	  buflen += 1000;
+	  buffer = __alloca (buflen);
+	}
+
+      if (result == 0 && pwd.pw_dir)
+	*word = w_addstr (*word, word_length, pwd.pw_dir);
+      else
+	{
+	  /* (invalid login name) */
+	  *word = w_addchar (*word, word_length, '~');
+	  if (*word != NULL)
+	    *word = w_addstr (*word, word_length, user);
+	}
+
+      *offset = i - 1;
+    }
+  return *word ? 0 : WRDE_NOSPACE;
+}
+
+static int
+parse_glob (char **word, size_t *word_length, const char *words,
+	    size_t *offset, int flags, wordexp_t *pwordexp, char *ifs)
+{
+  /* We are poised just after a '*' or a '{'. */
+  int error;
+  glob_t globbuf;
+  int match;
+  char * matching_word;
+
+  for (; words[*offset]; (*offset)++)
+    switch (words[*offset])
+      {
+      case ' ':
+      case '\t':
+	break;
+
+      case '$':
+	error = parse_dollars (word, word_length, words, offset, flags,
+			       pwordexp);
+	if (error)
+	  return error;
+
+	continue;
+
+      default:
+	if (ifs == NULL || strchr (ifs, words[*offset]) == NULL)
+	  {
+	    *word = w_addchar (*word, word_length, words[*offset]);
+	    if (*word == NULL)
+	      return WRDE_NOSPACE;
+
+	    continue;
+	  }
+
+	break;
+      }
+
+  error = glob (*word, GLOB_NOCHECK, NULL, &globbuf);
+
+  if (error != 0)
+    {
+      /* We can only run into memory problems.  */
+      assert (error == GLOB_NOSPACE);
+
+      return WRDE_NOSPACE;
+    }
+
+  if (ifs && !*ifs)
+    {
+      /* No field splitting allowed */
+      *word_length = strlen (globbuf.gl_pathv[0]);
+      *word = realloc (*word, 1 + *word_length);
+      if (*word == NULL)
+	goto no_space;
+
+      strcpy (*word, globbuf.gl_pathv[0]);
+
+      for (match = 1; match < globbuf.gl_pathc; ++match)
+	{
+	  *word = w_addchar (*word, word_length, ' ');
+	  if (*word != NULL)
+	    *word = w_addstr (*word, word_length, globbuf.gl_pathv[match]);
+	}
+
+      /* Re-parse white space on return */
+      globfree (&globbuf);
+      --(*offset);
+      return *word ? 0 : WRDE_NOSPACE;
+    }
+
+  /* here ifs != "" */
+  free (*word);
+  *word = NULL;
+  *word_length = 0;
+
+  matching_word = malloc (1 + strlen (globbuf.gl_pathv[0]));
+  if (matching_word == NULL)
+    goto no_space;
+
+  strcpy (matching_word, globbuf.gl_pathv[0]);
+  if (w_addword (pwordexp, matching_word) == WRDE_NOSPACE)
+    goto no_space;
+
+  for (match = 1; match < globbuf.gl_pathc; ++match)
+    {
+      matching_word = malloc (1 + strlen (globbuf.gl_pathv[match]));
+      if (matching_word == NULL)
+	goto no_space;
+
+      strcpy (matching_word, globbuf.gl_pathv[match]);
+      if (w_addword (pwordexp, matching_word) == WRDE_NOSPACE)
+	goto no_space;
+    }
+
+  globfree (&globbuf);
+
+  /* Re-parse white space on return */
+  --(*offset);
+  return 0;
+
+no_space:
+  globfree (&globbuf);
+  return WRDE_NOSPACE;
+}
+
+static int
+parse_squote (char **word, size_t *word_length, const char *words,
+	      size_t *offset)
+{
+  /* We are poised just after a single quote */
+  for (; words[*offset]; ++(*offset))
+    {
+      if (words[*offset] != '\'')
+	{
+	  *word = w_addchar (*word, word_length, words[*offset]);
+	  if (*word == NULL)
+	    return WRDE_NOSPACE;
+	}
+      else return 0;
+    }
+
+  /* Unterminated string */
+  return WRDE_SYNTAX;
+}
+
+/* Functions to evaluate an arithmetic expression */
+static int
+eval_expr_val (char **expr, int *result)
 {
+  int sgn = +1;
+  char *digit;
+
+  /* Skip white space */
+  for (digit = *expr; digit && *digit && isspace (*digit); ++digit);
+
+  switch (*digit)
+    {
+    case '(':
+
+      /* Scan for closing paren */
+      for (++digit; **expr && **expr != ')'; ++(*expr));
+
+      /* Is there one? */
+      if (!**expr)
+	return WRDE_SYNTAX;
+
+      *(*expr)++ = 0;
+
+      if (eval_expr(digit, result))
+	return WRDE_SYNTAX;
+
+      return 0;
+
+    case '+':	/* Positive value */
+      ++digit;
+      break;
+
+    case '-':	/* Negative value */
+      ++digit;
+      sgn = -1;
+      break;
+
+    default:
+      if (!isdigit (*digit))
+	return WRDE_SYNTAX;
+    }
+
+  *result = 0;
+  for (; *digit && isdigit(*digit); ++digit)
+    *result = (*result * 10) + (*digit - '0');
+
+  *expr = digit;
+  *result *= sgn;
+  return 0;
+}
+
+static int
+eval_expr_multdiv (char **expr, int *result)
+{
+  int arg;
+
+  /* Read a Value */
+  if (eval_expr_val (expr, result))
+    return WRDE_SYNTAX;
+
+  while (**expr)
+    {
+      /* Skip white space */
+      for (; *expr && **expr && isspace (**expr); ++(*expr));
+
+      if (**expr == '*')
+	{
+	  (*expr)++;
+	  if ((eval_expr_val (expr, &arg)) != 0)
+	    return WRDE_SYNTAX;
+
+	  *result *= arg;
+	}
+      else if (**expr == '/')
+	{
+	  (*expr)++;
+	  if ((eval_expr_val (expr, &arg)) != 0)
+	    return WRDE_SYNTAX;
+
+	  *result /= arg;
+	}
+      else break;
+    }
+
+  return 0;
+}
+
+static int
+eval_expr (char *expr, int *result)
+{
+  int arg;
+
+  /* Read a Multdiv */
+  if ((eval_expr_multdiv (&expr, result)) != 0)
+    return WRDE_SYNTAX;
+
+  while (*expr)
+    {
+      /* Skip white space */
+      for (; expr && *expr && isspace (*expr); ++expr);
+
+      if (*expr == '+')
+	{
+	  expr++;
+	  if ((eval_expr_multdiv (&expr, &arg)) != 0)
+	    return WRDE_SYNTAX;
+
+	  *result += arg;
+	}
+      else if (*expr == '-')
+	{
+	  expr++;
+	  if ((eval_expr_multdiv (&expr, &arg)) != 0)
+	    return WRDE_SYNTAX;
+
+	  *result -= arg;
+	}
+      else break;
+    }
+
+  return 0;
+}
+
+static int
+parse_arith (char **word, size_t *word_length, const char *words,
+	     size_t *offset, int flags, int bracket)
+{
+  /* We are poised just after "$((" or "$[" */
   int error;
+  int paren_depth = 1;
+  size_t expr_length = 0;
+  char *expr = calloc (1, sizeof (char));	/* ??? */
+
+  if (expr == NULL)
+    return WRDE_NOSPACE;
+
+  for (; words[*offset]; ++(*offset))
+    {
+      switch (words[*offset])
+	{
+	case '$':
+	  error = parse_dollars (&expr, &expr_length,
+				 words, offset, flags, NULL);
+	  /* The NULL here is to tell parse_dollars not to
+	   * split the fields.
+	   */
+	  if (error)
+	    {
+	      free (expr);
+	      return error;
+	    }
+	  break;
+
+	case '`':
+	  (*offset)++;
+	  error = parse_backtick (&expr, &expr_length,
+				  words, offset, flags, NULL);
+	  /* The NULL here is to tell parse_backtick not to
+	   * split the fields.
+	   */
+	  if (error)
+	    {
+	      free (expr);
+	      return error;
+	    }
+	  break;
+
+	case '\\':
+	  error = parse_qtd_backslash (&expr, &expr_length, words, offset);
+	  if (error)
+	    {
+	      free (expr);
+	      return error;
+	    }
+	  /* I think that a backslash within an
+	   * arithmetic expansion is bound to
+	   * cause an error sooner or later anyway though.
+	   */
+	  break;
+
+	case ')':
+	  if (--paren_depth == 0)
+	    {
+	      char *result;
+	      int numresult = 0;
+
+	      if (bracket || words[1 + *offset] != ')')
+		return WRDE_SYNTAX;
+
+	      ++(*offset);
+
+	      /* Go - evaluate. */
+	      if (*expr &&
+		  eval_expr (expr, &numresult) != 0)
+		return WRDE_SYNTAX;
+
+	      result = __alloca (100);
+	      __snprintf (result, 100, "%d", numresult);
+	      *word = w_addstr (*word, word_length, result);
+	      free (expr);
+	      return *word ? 0 : WRDE_NOSPACE;
+	    }
+	  expr = w_addchar (expr, &expr_length, words[*offset]);
+	  if (expr == NULL)
+	    return WRDE_NOSPACE;
+
+	  break;
+
+	case ']':
+	  if (bracket && paren_depth == 1)
+	    {
+	      char *result;
+	      int numresult = 0;
+
+	      /* Go - evaluate. */
+	      if (*expr && eval_expr (expr, &numresult) != 0)
+		return WRDE_SYNTAX;
+
+	      result = __alloca (100);
+	      __snprintf (result, 100, "%d", numresult);
+	      *word = w_addstr (*word, word_length, result);
+	      free (expr);
+	      return *word ? 0 : WRDE_NOSPACE;
+	    }
+
+	  free (expr);
+	  return WRDE_SYNTAX;
+
+	case '\n':
+	case ';':
+	case '{':
+	case '}':
+	  free (expr);
+	  return WRDE_BADCHAR;
+
+	case '(':
+	  ++paren_depth;
+	default:
+	  expr = w_addchar (expr, &expr_length, words[*offset]);
+	  if (expr == NULL)
+	    return WRDE_NOSPACE;
+	}
+    }
+
+  /* Premature end */
+  free (expr);
+  return WRDE_SYNTAX;
+}
+
+/* Function to execute a command and retrieve the results */
+/* pwordexp contains NULL if field-splitting is forbidden */
+static int
+exec_comm (char *comm, char **word, size_t *word_length, int flags,
+	   wordexp_t *pwordexp)
+{
+  int   fildes[2];
+  int bufsize = 128;
+  int buflen;
+  int state = 0;
+  int i;
+  char *sh, *buffer;
   pid_t pid;
-  int d[2];
-  int status;
+  /* 'state' is:
+   *  0 until first non-(whitespace-ifs)
+   *  1 after a non-ifs
+   *  2 after non-(whitespace-ifs)
+   */
 
-  FILE *f;
-  size_t wordc, start, buflen;
-  char *buf;
+  /* Don't fork() unless necessary */
+  if (!comm || !*comm)
+    return 0;
 
-  /* Create the pipe through which we will communicate to the shell.  */
-  if (pipe (d) < 0)
-    return -1;
+  if (pipe (fildes))
+    /* Bad */
+    return WRDE_NOSPACE;
 
-  pid = fork ();
-  if (pid < 0)
-    return -1;
+  if ((pid = fork ()) < 0)
+    {
+      /* Bad */
+      return WRDE_NOSPACE;
+    }
 
   if (pid == 0)
     {
-      /* Child.  Run the shell.  */
+      /* Child */
+      /* Redirect input and output */
+      dup2 (fildes[1], 1);
 
-      const char *argv[5];
+      /* Close stderr if we have to */
+      if ((flags & WRDE_SHOWERR) == 0)
+	close (2);
 
-      close (d[STDIN_FILENO]);
-      dup2 (d[STDOUT_FILENO], STDOUT_FILENO);
-      if (!(flags & WRDE_SHOWERR))
-	close (STDERR_FILENO);
+      execl (_PATH_BSHELL, _PATH_BSHELL, "-c", comm, NULL);
+      /* Bad */
+      exit (1);
+    }
 
-      i = 0;
-      argv[i++] = SHELL_NAME;
-      if (flags & WRDE_NOCMD)
-	argv[i++] = "-P";
-      if (flags & WRDE_UNDEF)
-	argv[i++] = "-u";
-      argv[i++] = "-w";
-      argv[i++] = string;
-      argv[i++] = NULL;
+  /* Parent */
+
+  close (fildes[1]);
+  buffer = __alloca (bufsize);
 
-      execv (SHELL_PATH, argv);
-      _exit (WRDE_NOSPACE);
+  if (!pwordexp)
+    { /* Quoted - no field splitting */
+
+      while (1)
+	{
+	  if ((buflen = read (fildes[0], buffer, bufsize)) < 1)
+	    {
+	      if (waitpid (pid, NULL, WNOHANG) == 0)
+		continue;
+	      if ((buflen = read (fildes[0], buffer, bufsize)) < 1)
+		break;
+	    }
+
+	  for (i = 0; i < buflen; ++i)
+	    {
+	      *word = w_addchar (*word, word_length, buffer[i]);
+	      if (*word == NULL)
+		{
+		  close (fildes[0]);
+		  return WRDE_NOSPACE;
+		}
+	    }
+	}
+
+      close (fildes[0]);
+      return 0;
     }
 
-  /* Parent.  */
+  /* Not quoted - split fields.
+   * NB. This isn't done properly yet.
+   */
+  while (1)
+    {
+      if ((buflen = read (fildes[0], buffer, bufsize)) < 1)
+	{
+	  if (waitpid (pid, NULL, WNOHANG) == 0)
+	    continue;
+	  if ((read (fildes[0], buffer, bufsize)) < 1)
+	    break;
+	}
 
-  buf = NULL;
-  error = WRDE_NOSPACE;
+      for (i = 0; i < buflen; ++i)
+	{
+	  /* What if these aren't field separators? FIX */
+	  if ((buffer[i] == ' ') || (buffer[i] == '\t') || (buffer[i] == '\n'))
+	    {
+	      if (state != 0)
+		state = 2;
+	      continue;
+	    }
 
-  close (d[STDOUT_FILENO]);
-  f = fdopen (d[STDIN_FILENO]);
-  if (f == NULL)
-    goto lose;
+	  if (state == 2)
+	    {
+	      /* End of word */
+	      if (w_addword (pwordexp, *word) == WRDE_NOSPACE)
+		{
+		  close (fildes[0]);
+		  return WRDE_NOSPACE;
+		}
 
-  /* Read the number of words and number of bytes from the shell.  */
-  if (fscanf (f, "%u", &wordc) != 1 || getc (f) != '\0' ||
-      fscanf (f, "%u", &buflen) != 1 || getc (f) != '\0')
-    goto lose;
+	      *word = NULL;
+	      *word_length = 0;
+	    }
 
-  /* Read the words from the shell, and wait for it to return.  */
-  buflen += wordc;
-  buf = malloc (buflen);
-  if (buf == NULL ||
-      fread (buf, buflen, 1, f) != 1 ||
-      waitpid (pid, &status, 0) != pid)
-    goto lose;
+	  state = 1;
+	  *word = w_addchar (*word, word_length, buffer[i]);
+	  if (*word == NULL)
+	    {
+	      close (fildes[0]);
+	      return WRDE_NOSPACE;
+	    }
+	}
+    }
 
-  if (WIFEXITED (status))
+  close (fildes[0]);
+  return 0;
+}
+
+static int
+parse_comm (char **word, size_t *word_length, const char *words,
+	    size_t *offset, int flags, wordexp_t *pwordexp)
+{
+  /* We are poised just after "$(" */
+  int paren_depth = 1;
+  int error;
+  size_t comm_length = 0;
+  char *comm = calloc (1, sizeof (char));	/* ??? */
+
+  if (comm == NULL)
+    return WRDE_NOSPACE;
+
+  for (; words[*offset]; ++(*offset))
     {
-      if (WEXITSTATUS (status) != 0)
+      switch (words[*offset])
 	{
-	  error = WEXITSTATUS (status);
-	  goto lose;
+	case ')':
+	  if (--paren_depth == 0)
+	    {
+	      /* Go -- give script to the shell */
+	      error = exec_comm (comm, word, word_length, flags, pwordexp);
+	      free (comm);
+	      return error;
+	    }
+
+	  /* This is just part of the script */
+	  comm = w_addchar (comm, &comm_length, words[*offset]);
+	  if (comm == NULL)
+	    return WRDE_NOSPACE;
+
+	  break;
+
+	case '(':
+	  paren_depth++;
+	default:
+	  comm = w_addchar (comm, &comm_length, words[*offset]);
+	  if (comm == NULL)
+	    return WRDE_NOSPACE;
+
+	  break;
 	}
     }
-  else
-    goto lose;
 
-  /* Pack the structure.  */
+  /* Premature end */
+  free (comm);
+  return WRDE_SYNTAX;
+}
 
-  start = 0;
-  if (flags & WRDE_DOOFFS)
-    start += pwordexp->we_offs;
-  if (flags & WRDE_APPEND)
-    start += pwordexp->we_wordc;
-  wordc = start + wordc + 1;
-
-  if (flags & WRDE_APPEND)
-    wordv = (char **) realloc ((void *) pwordexp->we_wordv,
-			       wordc * sizeof (char *));
+static int
+parse_param (char **word, size_t *word_length, const char *words,
+	     size_t *offset, int flags, wordexp_t *pwordexp)
+{
+  /* We are poised just after "$" */
+  size_t start = *offset;
+  size_t env_length = 0;
+  size_t pat_length = 0;
+  char *env = calloc (1, sizeof (char));	/* ??? */
+  char *pattern = calloc (1, sizeof (char));	/* ??? */
+  char *value;
+  char action = 0;
+  int prefix = 0;
+  int suffix = 0;
+  int colon_seen = 0;
+  int depth = 0;
+  int error;
+
+  if ((env == NULL) || (pattern == NULL))
+    return WRDE_NOSPACE;
+
+  for (; words[*offset]; ++(*offset))
+    {
+      switch (words[*offset])
+	{
+	case '{':
+	  if (action || prefix || suffix)
+	    {
+	      ++depth;
+	      pattern = w_addchar (pattern, &pat_length, words[*offset]);
+	      if (pattern == NULL)
+		goto no_space;
+
+	      break;
+	    }
+
+	  if (*offset == start)
+	    break;
+	  /* Otherwise evaluate */
+	  /* (and re-parse this character) */
+	  --(*offset);
+	  goto envsubst;
+
+	case '}':
+	  if (words[start] != '{')
+	    {
+	      --(*offset);
+	    }
+
+	  if (action || prefix || suffix)
+	    {
+	      if (--depth)
+		{
+		  pattern = w_addchar (pattern, &pat_length, words[*offset]);
+		  if (pattern == NULL)
+		    goto no_space;
+
+		  break;
+		}
+	    }
+
+	  /* Evaluate */
+	  goto envsubst;
+
+	case '#':
+	case '%':
+	  if (words[start] == '{')
+	    {
+	      /* At the start?  (ie. 'string length') */
+	      if (*offset == start + 1)
+		break;
+
+	      /* Separating variable name from prefix pattern? */
+	      if (words[*offset] == '#')
+		{
+		  if ((prefix < 2) && (!suffix))
+		    {
+		      ++prefix;
+		      break;
+		    }
+		}
+	      else
+		{
+		  if ((suffix < 2) && (!prefix))
+		    {
+		      ++suffix;
+		      break;
+		    }
+		}
+
+	      /* Must be part of prefix/suffix pattern. */
+	      pattern = w_addchar (pattern, &pat_length, words[*offset]);
+	      if (pattern == NULL)
+		goto no_space;
+
+	      break;
+	    }
+	  /* Otherwise evaluate */
+	  /* (and re-parse this character) */
+	  --(*offset);
+	  goto envsubst;
+
+	case ':':
+	  if (!*env)
+	    {
+	      free (env);
+	      free (pattern);
+	      return WRDE_SYNTAX;
+	    }
+
+	  if (action || prefix || suffix)
+	    {
+	      pattern = w_addchar (pattern, &pat_length, words[*offset]);
+	      if (pattern == NULL)
+		goto no_space;
+
+	      break;
+	    }
+
+	  if ((words[1 + *offset] == '-') || (words[1 + *offset] == '=') ||
+	      (words[1 + *offset] == '?') || (words[1 + *offset] == '+'))
+	    {
+	      colon_seen = 1;
+	      break;
+	    }
+
+	  free (env);
+	  free (pattern);
+	  return WRDE_SYNTAX;
+
+	case '-':
+	case '=':
+	case '?':
+	case '+':
+	  if (!*env)
+	    {
+	      free (env);
+	      free (pattern);
+	      return WRDE_SYNTAX;
+	    }
+
+	  if (action || prefix || suffix)
+	    {
+	      pattern = w_addchar (pattern, &pat_length, words[*offset]);
+	      if (pattern == NULL)
+		{
+		  free (env);
+		  return WRDE_NOSPACE;
+		}
+
+	      break;
+	    }
+
+	  action = words[*offset];
+	  break;
+
+	case '\\':
+	  if (action || prefix || suffix)
+	    {
+	      error = parse_qtd_backslash (word, word_length, words, offset);
+	      if (error == 0)
+		break;
+	    }
+	  else
+	    {
+	      error = WRDE_SYNTAX;
+	    }
+
+	  free (env);
+	  free (pattern);
+	  return error;
+
+	default:
+	  if (action || prefix || suffix)
+	    {
+	      pattern = w_addchar (pattern, &pat_length, words[*offset]);
+	      if (pattern == NULL)
+		goto no_space;
+
+	      break;
+	    }
+
+	  if ((words[start] == '{') || isalpha (words[*offset]))
+	    {
+	      env = w_addchar (env, &env_length, words[*offset]);
+	      if (env == NULL)
+		goto no_space;
+
+	      break;
+	    }
+
+	  --(*offset);
+	  goto envsubst;
+	}
+    }
+
+  /* End of input string */
+  --(*offset);
+
+envsubst:
+  if (words[start] == '{' && words[*offset] != '}')
+    {
+      free (env);
+      free (pattern);
+      return WRDE_SYNTAX;
+    }
+
+  if (!env || !*env)
+    {
+      *offset = start - 1;
+      *word = w_addchar (*word, word_length, '$');
+      free (env);
+      free (pattern);
+      return *word ? 0 : WRDE_NOSPACE;
+    }
+
+  value = getenv (env);
+
+  if (action || prefix || suffix)
+    {
+      switch (action)
+	{
+	case 0:
+	  /* For the time being, pattern is ignored */
+	  printf ("Pattern: %s\nPrefix: %d\nSuffix: %d\n", pattern, prefix, suffix);
+	  break;
+
+	case '?':
+	  if (value && *value)
+	    break;
+
+	  if (!colon_seen && value)
+	    {
+	      /* Substitute NULL */
+	      free (env);
+	      free (pattern);
+	      return 0;
+	    }
+
+	  /* Error - exit */
+	  fprintf (stderr, "%s: ", env);
+
+	  if (*pattern)
+	    {
+	      /* Expand 'pattern' and write it to stderr */
+	      wordexp_t	we;
+
+	      error = wordexp (pattern, &we, flags);
+
+	      if (error == 0)
+		{
+		  int i;
+
+		  for (i = 0; i < we.we_wordc; ++i)
+		    {
+		      fprintf (stderr, "%s%s", i ? " " : "", we.we_wordv[i]);
+		    }
+
+		  fprintf (stderr, "\n");
+		  error = WRDE_BADVAL;
+		}
+
+	      wordfree (&we);
+	      free (env);
+	      free (pattern);
+	      return error;
+	    }
+
+	  fprintf (stderr, "parameter null or not set\n");
+	  free (env);
+	  free (pattern);
+	  return WRDE_BADVAL;
+
+	default:
+	  printf ("warning: parameter substitution does not yet support \"%s%c\"\n", colon_seen?":":"", action);
+	}
+    }
+
+  free (env);
+  free (pattern);
+
+  if (!value)
+    {
+      /* Variable not defined */
+      if (flags & WRDE_UNDEF)
+	return WRDE_SYNTAX;
+
+      return 0;
+    }
+
+  if (!pwordexp)
+    /* Quoted - no field split */
+    *word = w_addstr (*word, word_length, value);
   else
-    wordv = (char **) malloc (wordc * sizeof (char *));
-  if (wordv == NULL)
-    goto lose;
+    /* Should field-split here - FIX */
+    *word = w_addstr (*word, word_length, value);
 
-  if (flags & WRDE_DOOFFS)
-    for (i = 0; i < pwordexp->we_offs; ++i)
-      wordv[i] = NULL;
+  return *word ? 0 : WRDE_NOSPACE;
+
+no_space:
+  if (env)
+    free (env);
+
+  if (pattern)
+    free (pattern);
 
-  for (i = start; i < wordc; ++i)
+  return WRDE_NOSPACE;
+}
+
+static int
+parse_dollars (char **word, size_t *word_length, const char *words,
+	       size_t *offset, int flags, wordexp_t *pwordexp)
+{
+  /* We are poised _at_ "$" */
+  switch (words[1 + *offset])
     {
-      pwordexp->we_wordv[i] = buf;
-      buf = strchr (buf, '\0') + 1;
+    case '"':
+    case '\'':
+    case 0:
+      *word = w_addchar (*word, word_length, '$');
+      return *word ? 0 : WRDE_NOSPACE;
+
+    case '(':
+      if (words[2 + *offset] == '(')
+	{
+	  (*offset) += 3;
+	  /* Call parse_arith -- 0 is for "no brackets" */
+	  return parse_arith (word, word_length, words, offset, flags, 0);
+	}
+
+      if (flags & WRDE_NOCMD)
+	return WRDE_CMDSUB;
+
+      (*offset) += 2;
+      return parse_comm (word, word_length, words, offset, flags, pwordexp);
+
+    case '[':
+      (*offset) += 2;
+      /* Call parse_arith -- 1 is for "brackets" */
+      return parse_arith (word, word_length, words, offset, flags, 1);
+
+    case '{':
+    default:
+      ++(*offset);	/* parse_param needs to know if "{" is there */
+      return parse_param (word, word_length, words, offset, flags, pwordexp);
     }
-  wordv[i] = NULL;
+}
 
-  if (flags & WRDE_REUSE)
+static int
+parse_backtick (char **word, size_t *word_length, const char *words,
+		size_t *offset, int flags, wordexp_t *pwordexp)
+{
+  /* We are poised just after "`" */
+  int error;
+  size_t comm_length = 0;
+  char *comm = calloc (1, sizeof (char));	/* ??? */
+  int squoting = 0;
+
+  for (; words[*offset]; ++(*offset))
     {
-      free (pwordexp->we_wordv[0]);
-      if (!(flags & WRDE_APPEND))
-	free (pwordexp->we_wordv);
+      switch (words[*offset])
+	{
+	case '`':
+	  /* Go -- give the script to the shell */
+	  error = exec_comm (comm, word, word_length, flags, pwordexp);
+	  free (comm);
+	  return error;
+
+	case '\\':
+	  if (squoting)
+	    {
+	      error = parse_qtd_backslash (&comm, &comm_length, words, offset);
+
+	      if (error)
+		{
+		  free (comm);
+		  return error;
+		}
+
+	      break;
+	    }
+
+	  ++(*offset);
+	  error = parse_backslash (&comm, &comm_length, words, offset);
+
+	  if (error)
+	    {
+	      free (comm);
+	      return error;
+	    }
+
+	  break;
+
+	case '\'':
+	  squoting = 1 - squoting;
+	default:
+	  comm = w_addchar (comm, &comm_length, words[*offset]);
+	  if (comm == NULL)
+	    return WRDE_NOSPACE;
+	}
     }
 
-  pwordexp->we_wordc = wordc;
-  pwordexp->we_wordv = wordv;
+  /* Premature end */
+  free (comm);
+  return WRDE_SYNTAX;
+}
 
-  return 0;
+static int
+parse_dquote (char **word, size_t *word_length, const char *words,
+	      size_t *offset, int flags)
+{
+  /* We are poised just after a double-quote */
+  int error;
+
+  for (; words[*offset]; ++(*offset))
+    {
+      switch (words[*offset])
+	{
+	case '"':
+	  return 0;
+
+	case '$':
+	  error = parse_dollars (word, word_length, words, offset, flags,
+				 NULL);
+	  /* The NULL here is to tell parse_dollars not to
+	   * split the fields.
+	   */
+	  if (error)
+	    return error;
 
- lose:
-  {
-    int save;
-    save = errno;
-    (void) kill (pid, SIGKILL);
-    free (buf);
-    (void) waitpid (pid, (int *) NULL, 0);
-    errno = save;
-    return error;
-  }
+	  break;
+
+	case '`':
+	  if (flags & WRDE_NOCMD)
+	    {
+	      return WRDE_CMDSUB;
+	    }
+
+	  ++(*offset);
+	  error = parse_backtick (word, word_length, words, offset, flags,
+				  NULL);
+	  /* The NULL here is to tell parse_backtick not to
+	   * split the fields.
+	   */
+	  if (error)
+	    return error;
+
+	  break;
+
+	case '\\':
+	  error = parse_qtd_backslash (word, word_length, words, offset);
+
+	  if (error)
+	    return error;
+
+	  break;
+
+	default:
+	  *word = w_addchar (*word, word_length, words[*offset]);
+	  if (*word == NULL)
+	    return WRDE_NOSPACE;
+	}
+    }
+
+  /* Unterminated string */
+  return WRDE_SYNTAX;
 }
 
+/*
+ * wordfree() is to be called after pwordexp is finished with.
+ */
 
 void
-DEFUN(wordexp, (pwordexp), wordexp_t *pwordexp)
+wordfree (wordexp_t *pwordexp)
 {
-  /* All the other elts point into the first.  */
-  free (pwordexp->we_wordv[0]);
-  free (pwordexp->we_wordv);
+
+  /* wordexp can set pwordexp to NULL */
+  if (pwordexp && pwordexp->we_wordv)
+    {
+      char **wordv = pwordexp->we_wordv;
+
+      for (wordv += pwordexp->we_offs; *wordv; ++wordv)
+	free (*wordv);
+
+      free (pwordexp->we_wordv);
+      pwordexp->we_wordv = NULL;
+    }
+}
+
+/*
+ * wordexp()
+ */
+
+int
+wordexp (const char *words, wordexp_t *pwordexp, int flags)
+{
+  size_t wordv_offset;
+  size_t words_offset;
+  size_t word_length = 0;
+  int error;
+  char *word = NULL;
+  char *ifs;
+  char ifs_white[4];
+  char **old_wordv = pwordexp->we_wordv;
+  size_t old_wordc = pwordexp->we_wordc;
+
+  if (flags & WRDE_REUSE)
+    /* Minimal implementation of WRDE_REUSE for now */
+    wordfree (pwordexp);
+
+  if (flags & WRDE_DOOFFS)
+    {
+      pwordexp->we_wordv = calloc (1 + pwordexp->we_offs, sizeof (char *));
+      if (pwordexp->we_wordv == NULL)
+	return WRDE_NOSPACE;
+    }
+  else
+    {
+      pwordexp->we_wordv = calloc (1, sizeof (char *));
+      if (pwordexp->we_wordv == NULL)
+	return WRDE_NOSPACE;
+
+      pwordexp->we_offs = 0;
+    }
+
+  if ((flags & WRDE_APPEND) == 0)
+    pwordexp->we_wordc = 0;
+
+  wordv_offset = pwordexp->we_offs + pwordexp->we_wordc;
+
+  /* Find out what the field separators are.
+   * There are two types: whitespace and non-whitespace.
+   */
+  ifs = getenv ("IFS");
+
+  if (!ifs)
+    ifs = strcpy (ifs_white, " \t\n");
+  else
+    {
+      char *ifsch = ifs;
+      char *whch = ifs_white;
+
+      while (*ifsch != '\0')
+	if ((*ifsch == ' ') || (*ifsch == '\t') || (*ifsch == '\n'))
+	  {
+	    /* White space IFS.  Se first whether it is already in our
+	       collection.  */
+	    char *runp = ifs_white;
+
+	    while (runp < whch && *runp != '\0')
+	      ++runp;
+
+	    if (runp == whch)
+	      *whch++ = *ifsch;
+	  }
+      *whch = '\0';
+    }
+
+  for (words_offset = 0 ; words[words_offset] ; ++words_offset)
+    switch (words[words_offset])
+      {
+      case '\n':
+      case '|':
+      case '&':
+      case ';':
+      case '<':
+      case '>':
+      case '(':
+      case ')':
+      case '}':
+	/* Fail */
+	wordfree (pwordexp);
+	pwordexp->we_wordc = 0;
+	pwordexp->we_wordv = old_wordv;
+	return WRDE_BADCHAR;
+
+      case '\\':
+	error = parse_backslash (&word, &word_length, words, &words_offset);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      case '$':
+	error = parse_dollars (&word, &word_length, words, &words_offset,
+			       flags, pwordexp);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      case '`':
+	if (flags & WRDE_NOCMD)
+	  return WRDE_CMDSUB;
+
+	++words_offset;
+	error = parse_backtick (&word, &word_length, words, &words_offset,
+				flags, pwordexp);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      case '"':
+	++words_offset;
+	error = parse_dquote (&word, &word_length, words, &words_offset,
+			      flags);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      case '\'':
+	++words_offset;
+	error = parse_squote (&word, &word_length, words, &words_offset);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      case '~':
+	error = parse_tilde (&word, &word_length, words, &words_offset,
+			     pwordexp->we_wordc);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      case '*':
+      case '{':
+	error = parse_glob (&word, &word_length, words, &words_offset, flags,
+			    pwordexp, ifs);
+
+	if (error)
+	  goto do_error;
+
+	break;
+
+      default:
+	/* Is it a field separator? */
+	if (strchr (ifs, words[words_offset]) == NULL)
+	  {
+	    /* "Ordinary" character -- add it to word */
+
+	    word = w_addchar (word, &word_length, words[words_offset]);
+	    if (word == NULL)
+	      {
+		error = WRDE_NOSPACE;
+		goto do_error;
+	      }
+
+	    break;
+	  }
+
+	/* Field separator */
+	if (strchr (ifs_white, words[words_offset]))
+	  {
+	    /* It's a whitespace IFS char.  Ignore it at the beginning
+	       of a line and ignore multiple instances.  */
+	    if (!word || !*word)
+	      break;
+
+	    if (w_addword (pwordexp, word) == WRDE_NOSPACE)
+	      {
+		error = WRDE_NOSPACE;
+		goto do_error;
+	      }
+
+	    word = NULL;
+	    word_length = 0;
+	    break;
+	  }
+
+	/* It's a non-whitespace IFS char */
+	if (!word)
+	  {
+	    word = calloc (1, sizeof (char));	/* ??? */
+	    if (word == NULL)
+	      {
+		error = WRDE_NOSPACE;
+		goto do_error;
+	      }
+	  }
+
+	if (w_addword (pwordexp, word) == WRDE_NOSPACE)
+	  {
+	    error = WRDE_NOSPACE;
+	    goto do_error;
+	  }
+
+	word = NULL;
+	word_length = 0;
+      }
+
+  /* End of string */
+
+  /* There was a field separator at the end */
+  if (!word || !*word)
+    return 0;
+
+  /* There was no field separator at the end */
+  return w_addword (pwordexp, word);
+
+do_error:
+  /* Error:
+	free memory used, set we_wordc and wd_wordv back to what they were.
+   */
+  if (word != NULL)
+    free (word);
+
+  wordfree (pwordexp);
+  pwordexp->we_wordv = old_wordv;
+  pwordexp->we_wordc = old_wordc;
+  return error;
 }