Adding upstream version 5.1.upstream/5.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1441 insertions, 0 deletions

diff --git a/general.c b/general.c
new file mode 100644
index 0000000..50d5216
--- /dev/null
+++ b/general.c
@@ -0,0 +1,1441 @@
+/* general.c -- Stuff that is used by all files. */
+
+/* Copyright (C) 1987-2020 Free Software Foundation, Inc.
+
+   This file is part of GNU Bash, the Bourne Again SHell.
+
+   Bash is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   Bash is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config.h"
+
+#include "bashtypes.h"
+#if defined (HAVE_SYS_PARAM_H)
+#  include <sys/param.h>
+#endif
+#include "posixstat.h"
+
+#if defined (HAVE_UNISTD_H)
+#  include <unistd.h>
+#endif
+
+#include "filecntl.h"
+#include "bashansi.h"
+#include <stdio.h>
+#include "chartypes.h"
+#include <errno.h>
+
+#include "bashintl.h"
+
+#include "shell.h"
+#include "parser.h"
+#include "flags.h"
+#include "findcmd.h"
+#include "test.h"
+#include "trap.h"
+#include "pathexp.h"
+
+#include "builtins/common.h"
+
+#if defined (HAVE_MBSTR_H) && defined (HAVE_MBSCHR)
+#  include <mbstr.h>		/* mbschr */
+#endif
+
+#include <tilde/tilde.h>
+
+#if !defined (errno)
+extern int errno;
+#endif /* !errno */
+
+#ifdef __CYGWIN__
+#  include <sys/cygwin.h>
+#endif
+
+static char *bash_special_tilde_expansions PARAMS((char *));
+static int unquoted_tilde_word PARAMS((const char *));
+static void initialize_group_array PARAMS((void));
+
+/* A standard error message to use when getcwd() returns NULL. */
+const char * const bash_getcwd_errstr = N_("getcwd: cannot access parent directories");
+
+/* Do whatever is necessary to initialize `Posix mode'.  This currently
+   modifies the following variables which are controlled via shopt:
+      interactive_comments
+      source_uses_path
+      expand_aliases
+      inherit_errexit
+      print_shift_error
+      posixglob
+
+   and the following variables which cannot be user-modified:
+
+      source_searches_cwd
+
+  If we add to the first list, we need to change the table and functions
+  below */
+
+static struct {
+  int *posix_mode_var;
+} posix_vars[] = 
+{
+  &interactive_comments,
+  &source_uses_path,
+  &expand_aliases,
+  &inherit_errexit,
+  &print_shift_error,
+  0
+};
+
+static char *saved_posix_vars = 0;
+
+void
+posix_initialize (on)
+     int on;
+{
+  /* Things that should be turned on when posix mode is enabled. */
+  if (on != 0)
+    {
+      interactive_comments = source_uses_path = expand_aliases = 1;
+      inherit_errexit = 1;
+      source_searches_cwd = 0;
+      print_shift_error = 1;
+    }
+
+  /* Things that should be turned on when posix mode is disabled. */
+  else if (saved_posix_vars)		/* on == 0, restore saved settings */
+    {
+      set_posix_options (saved_posix_vars);
+      free (saved_posix_vars);
+      saved_posix_vars = 0;
+    }
+  else	/* on == 0, restore a default set of settings */
+    {
+      source_searches_cwd = 1;
+      expand_aliases = interactive_shell;
+      print_shift_error = 0;
+    }
+}
+
+int
+num_posix_options ()
+{
+  return ((sizeof (posix_vars) / sizeof (posix_vars[0])) - 1);
+}
+
+char *
+get_posix_options (bitmap)
+     char *bitmap;
+{
+  register int i;
+
+  if (bitmap == 0)
+    bitmap = (char *)xmalloc (num_posix_options ());	/* no trailing NULL */
+  for (i = 0; posix_vars[i].posix_mode_var; i++)
+    bitmap[i] = *(posix_vars[i].posix_mode_var);
+  return bitmap;
+}
+
+#undef save_posix_options
+void
+save_posix_options ()
+{
+  saved_posix_vars = get_posix_options (saved_posix_vars);
+}
+
+void
+set_posix_options (bitmap)
+     const char *bitmap;
+{
+  register int i;
+
+  for (i = 0; posix_vars[i].posix_mode_var; i++)
+    *(posix_vars[i].posix_mode_var) = bitmap[i];
+}
+
+/* **************************************************************** */
+/*								    */
+/*  Functions to convert to and from and display non-standard types */
+/*								    */
+/* **************************************************************** */
+
+#if defined (RLIMTYPE)
+RLIMTYPE
+string_to_rlimtype (s)
+     char *s;
+{
+  RLIMTYPE ret;
+  int neg;
+
+  ret = 0;
+  neg = 0;
+  while (s && *s && whitespace (*s))
+    s++;
+  if (s && (*s == '-' || *s == '+'))
+    {
+      neg = *s == '-';
+      s++;
+    }
+  for ( ; s && *s && DIGIT (*s); s++)
+    ret = (ret * 10) + TODIGIT (*s);
+  return (neg ? -ret : ret);
+}
+
+void
+print_rlimtype (n, addnl)
+     RLIMTYPE n;
+     int addnl;
+{
+  char s[INT_STRLEN_BOUND (RLIMTYPE) + 1], *p;
+
+  p = s + sizeof(s);
+  *--p = '\0';
+
+  if (n < 0)
+    {
+      do
+	*--p = '0' - n % 10;
+      while ((n /= 10) != 0);
+
+      *--p = '-';
+    }
+  else
+    {
+      do
+	*--p = '0' + n % 10;
+      while ((n /= 10) != 0);
+    }
+
+  printf ("%s%s", p, addnl ? "\n" : "");
+}
+#endif /* RLIMTYPE */
+
+/* **************************************************************** */
+/*								    */
+/*		       Input Validation Functions		    */
+/*								    */
+/* **************************************************************** */
+
+/* Return non-zero if all of the characters in STRING are digits. */
+int
+all_digits (string)
+     const char *string;
+{
+  register const char *s;
+
+  for (s = string; *s; s++)
+    if (DIGIT (*s) == 0)
+      return (0);
+
+  return (1);
+}
+
+/* Return non-zero if the characters pointed to by STRING constitute a
+   valid number.  Stuff the converted number into RESULT if RESULT is
+   not null. */
+int
+legal_number (string, result)
+     const char *string;
+     intmax_t *result;
+{
+  intmax_t value;
+  char *ep;
+
+  if (result)
+    *result = 0;
+
+  if (string == 0)
+    return 0;
+
+  errno = 0;
+  value = strtoimax (string, &ep, 10);
+  if (errno || ep == string)
+    return 0;	/* errno is set on overflow or underflow */
+
+  /* Skip any trailing whitespace, since strtoimax does not. */
+  while (whitespace (*ep))
+    ep++;
+
+  /* If *string is not '\0' but *ep is '\0' on return, the entire string
+     is valid. */
+  if (*string && *ep == '\0')
+    {
+      if (result)
+	*result = value;
+      /* The SunOS4 implementation of strtol() will happily ignore
+	 overflow conditions, so this cannot do overflow correctly
+	 on those systems. */
+      return 1;
+    }
+    
+  return (0);
+}
+
+/* Return 1 if this token is a legal shell `identifier'; that is, it consists
+   solely of letters, digits, and underscores, and does not begin with a
+   digit. */
+int
+legal_identifier (name)
+     const char *name;
+{
+  register const char *s;
+  unsigned char c;
+
+  if (!name || !(c = *name) || (legal_variable_starter (c) == 0))
+    return (0);
+
+  for (s = name + 1; (c = *s) != 0; s++)
+    {
+      if (legal_variable_char (c) == 0)
+	return (0);
+    }
+  return (1);
+}
+
+/* Return 1 if NAME is a valid value that can be assigned to a nameref
+   variable.  FLAGS can be 2, in which case the name is going to be used
+   to create a variable.  Other values are currently unused, but could
+   be used to allow values to be stored and indirectly referenced, but
+   not used in assignments. */
+int
+valid_nameref_value (name, flags)
+     const char *name;
+     int flags;
+{
+  if (name == 0 || *name == 0)
+    return 0;
+
+  /* valid identifier */
+#if defined (ARRAY_VARS)  
+  if (legal_identifier (name) || (flags != 2 && valid_array_reference (name, 0)))
+#else
+  if (legal_identifier (name))
+#endif
+    return 1;
+
+  return 0;
+}
+
+int
+check_selfref (name, value, flags)
+     const char *name;
+     char *value;
+     int flags;
+{
+  char *t;
+
+  if (STREQ (name, value))
+    return 1;
+
+#if defined (ARRAY_VARS)
+  if (valid_array_reference (value, 0))
+    {
+      t = array_variable_name (value, 0, (char **)NULL, (int *)NULL);
+      if (t && STREQ (name, t))
+	{
+	  free (t);
+	  return 1;
+	}
+      free (t);
+    }
+#endif
+
+  return 0;	/* not a self reference */
+}
+
+/* Make sure that WORD is a valid shell identifier, i.e.
+   does not contain a dollar sign, nor is quoted in any way.
+   If CHECK_WORD is non-zero,
+   the word is checked to ensure that it consists of only letters,
+   digits, and underscores, and does not consist of all digits. */
+int
+check_identifier (word, check_word)
+     WORD_DESC *word;
+     int check_word;
+{
+  if (word->flags & (W_HASDOLLAR|W_QUOTED))	/* XXX - HASDOLLAR? */
+    {
+      internal_error (_("`%s': not a valid identifier"), word->word);
+      return (0);
+    }
+  else if (check_word && (all_digits (word->word) || legal_identifier (word->word) == 0))
+    {
+      internal_error (_("`%s': not a valid identifier"), word->word);
+      return (0);
+    }
+  else
+    return (1);
+}
+
+/* Return 1 if STRING is a function name that the shell will import from
+   the environment.  Currently we reject attempts to import shell functions
+   containing slashes, beginning with newlines or containing blanks.  In
+   Posix mode, we require that STRING be a valid shell identifier.  Not
+   used yet. */
+int
+importable_function_name (string, len)
+     const char *string;
+     size_t len;
+{
+  if (absolute_program (string))	/* don't allow slash */
+    return 0;
+  if (*string == '\n')			/* can't start with a newline */
+    return 0;
+  if (shellblank (*string) || shellblank(string[len-1]))
+    return 0;
+  return (posixly_correct ? legal_identifier (string) : 1);
+}
+
+int
+exportable_function_name (string)
+     const char *string;
+{
+  if (absolute_program (string))
+    return 0;
+  if (mbschr (string, '=') != 0)
+    return 0;
+  return 1;
+}
+
+/* Return 1 if STRING comprises a valid alias name.  The shell accepts
+   essentially all characters except those which must be quoted to the
+   parser (which disqualifies them from alias expansion anyway) and `/'. */
+int
+legal_alias_name (string, flags)
+     const char *string;
+     int flags;
+{
+  register const char *s;
+
+  for (s = string; *s; s++)
+    if (shellbreak (*s) || shellxquote (*s) || shellexp (*s) || (*s == '/'))
+      return 0;
+  return 1;
+}
+
+/* Returns non-zero if STRING is an assignment statement.  The returned value
+   is the index of the `=' sign.  If FLAGS&1 we are expecting a compound assignment
+   and require an array subscript before the `=' to denote an assignment
+   statement. */
+int
+assignment (string, flags)
+     const char *string;
+     int flags;
+{
+  register unsigned char c;
+  register int newi, indx;
+
+  c = string[indx = 0];
+
+#if defined (ARRAY_VARS)
+  /* If parser_state includes PST_COMPASSIGN, FLAGS will include 1, so we are
+     parsing the contents of a compound assignment. If parser_state includes
+     PST_REPARSE, we are in the middle of an assignment statement and breaking
+     the words between the parens into words and assignment statements, but
+     we don't need to check for that right now. Within a compound assignment,
+     the subscript is required to make the word an assignment statement. If
+     we don't have a subscript, even if the word is a valid assignment
+     statement otherwise, we don't want to treat it as one. */
+  if ((flags & 1) && c != '[')		/* ] */
+    return (0);
+  else if ((flags & 1) == 0 && legal_variable_starter (c) == 0)
+#else
+  if (legal_variable_starter (c) == 0)
+#endif
+    return (0);
+
+  while (c = string[indx])
+    {
+      /* The following is safe.  Note that '=' at the start of a word
+	 is not an assignment statement. */
+      if (c == '=')
+	return (indx);
+
+#if defined (ARRAY_VARS)
+      if (c == '[')
+	{
+	  newi = skipsubscript (string, indx, (flags & 2) ? 1 : 0);
+	  /* XXX - why not check for blank subscripts here, if we do in
+	     valid_array_reference? */
+	  if (string[newi++] != ']')
+	    return (0);
+	  if (string[newi] == '+' && string[newi+1] == '=')
+	    return (newi + 1);
+	  return ((string[newi] == '=') ? newi : 0);
+	}
+#endif /* ARRAY_VARS */
+
+      /* Check for `+=' */
+      if (c == '+' && string[indx+1] == '=')
+	return (indx + 1);
+
+      /* Variable names in assignment statements may contain only letters,
+	 digits, and `_'. */
+      if (legal_variable_char (c) == 0)
+	return (0);
+
+      indx++;
+    }
+  return (0);
+}
+
+int
+line_isblank (line)
+     const char *line;
+{
+  register int i;
+
+  if (line == 0)
+    return 0;		/* XXX */
+  for (i = 0; line[i]; i++)
+    if (isblank ((unsigned char)line[i]) == 0)
+      break;
+  return (line[i] == '\0');  
+}
+
+/* **************************************************************** */
+/*								    */
+/*	     Functions to manage files and file descriptors	    */
+/*								    */
+/* **************************************************************** */
+
+/* A function to unset no-delay mode on a file descriptor.  Used in shell.c
+   to unset it on the fd passed as stdin.  Should be called on stdin if
+   readline gets an EAGAIN or EWOULDBLOCK when trying to read input. */
+
+#if !defined (O_NDELAY)
+#  if defined (FNDELAY)
+#    define O_NDELAY FNDELAY
+#  endif
+#endif /* O_NDELAY */
+
+/* Make sure no-delay mode is not set on file descriptor FD. */
+int
+sh_unset_nodelay_mode (fd)
+     int fd;
+{
+  int flags, bflags;
+
+  if ((flags = fcntl (fd, F_GETFL, 0)) < 0)
+    return -1;
+
+  bflags = 0;
+
+  /* This is defined to O_NDELAY in filecntl.h if O_NONBLOCK is not present
+     and O_NDELAY is defined. */
+#ifdef O_NONBLOCK
+  bflags |= O_NONBLOCK;
+#endif
+
+#ifdef O_NDELAY
+  bflags |= O_NDELAY;
+#endif
+
+  if (flags & bflags)
+    {
+      flags &= ~bflags;
+      return (fcntl (fd, F_SETFL, flags));
+    }
+
+  return 0;
+}
+
+/* Just a wrapper for the define in include/filecntl.h */
+int
+sh_setclexec (fd)
+     int fd;
+{
+  return (SET_CLOSE_ON_EXEC (fd));
+}
+
+/* Return 1 if file descriptor FD is valid; 0 otherwise. */
+int
+sh_validfd (fd)
+     int fd;
+{
+  return (fcntl (fd, F_GETFD, 0) >= 0);
+}
+
+int
+fd_ispipe (fd)
+     int fd;
+{
+  errno = 0;
+  return ((lseek (fd, 0L, SEEK_CUR) < 0) && (errno == ESPIPE));
+}
+
+/* There is a bug in the NeXT 2.1 rlogind that causes opens
+   of /dev/tty to fail. */
+
+#if defined (__BEOS__)
+/* On BeOS, opening in non-blocking mode exposes a bug in BeOS, so turn it
+   into a no-op.  This should probably go away in the future. */
+#  undef O_NONBLOCK
+#  define O_NONBLOCK 0
+#endif /* __BEOS__ */
+
+void
+check_dev_tty ()
+{
+  int tty_fd;
+  char *tty;
+
+  tty_fd = open ("/dev/tty", O_RDWR|O_NONBLOCK);
+
+  if (tty_fd < 0)
+    {
+      tty = (char *)ttyname (fileno (stdin));
+      if (tty == 0)
+	return;
+      tty_fd = open (tty, O_RDWR|O_NONBLOCK);
+    }
+  if (tty_fd >= 0)
+    close (tty_fd);
+}
+
+/* Return 1 if PATH1 and PATH2 are the same file.  This is kind of
+   expensive.  If non-NULL STP1 and STP2 point to stat structures
+   corresponding to PATH1 and PATH2, respectively. */
+int
+same_file (path1, path2, stp1, stp2)
+     const char *path1, *path2;
+     struct stat *stp1, *stp2;
+{
+  struct stat st1, st2;
+
+  if (stp1 == NULL)
+    {
+      if (stat (path1, &st1) != 0)
+	return (0);
+      stp1 = &st1;
+    }
+
+  if (stp2 == NULL)
+    {
+      if (stat (path2, &st2) != 0)
+	return (0);
+      stp2 = &st2;
+    }
+
+  return ((stp1->st_dev == stp2->st_dev) && (stp1->st_ino == stp2->st_ino));
+}
+
+/* Move FD to a number close to the maximum number of file descriptors
+   allowed in the shell process, to avoid the user stepping on it with
+   redirection and causing us extra work.  If CHECK_NEW is non-zero,
+   we check whether or not the file descriptors are in use before
+   duplicating FD onto them.  MAXFD says where to start checking the
+   file descriptors.  If it's less than 20, we get the maximum value
+   available from getdtablesize(2). */
+int
+move_to_high_fd (fd, check_new, maxfd)
+     int fd, check_new, maxfd;
+{
+  int script_fd, nfds, ignore;
+
+  if (maxfd < 20)
+    {
+      nfds = getdtablesize ();
+      if (nfds <= 0)
+	nfds = 20;
+      if (nfds > HIGH_FD_MAX)
+	nfds = HIGH_FD_MAX;		/* reasonable maximum */
+    }
+  else
+    nfds = maxfd;
+
+  for (nfds--; check_new && nfds > 3; nfds--)
+    if (fcntl (nfds, F_GETFD, &ignore) == -1)
+      break;
+
+  if (nfds > 3 && fd != nfds && (script_fd = dup2 (fd, nfds)) != -1)
+    {
+      if (check_new == 0 || fd != fileno (stderr))	/* don't close stderr */
+	close (fd);
+      return (script_fd);
+    }
+
+  /* OK, we didn't find one less than our artificial maximum; return the
+     original file descriptor. */
+  return (fd);
+}
+ 
+/* Return non-zero if the characters from SAMPLE are not all valid
+   characters to be found in the first line of a shell script.  We
+   check up to the first newline, or SAMPLE_LEN, whichever comes first.
+   All of the characters must be printable or whitespace. */
+
+int
+check_binary_file (sample, sample_len)
+     const char *sample;
+     int sample_len;
+{
+  register int i;
+  unsigned char c;
+
+  for (i = 0; i < sample_len; i++)
+    {
+      c = sample[i];
+      if (c == '\n')
+	return (0);
+      if (c == '\0')
+	return (1);
+    }
+
+  return (0);
+}
+
+/* **************************************************************** */
+/*								    */
+/*		    Functions to manipulate pipes		    */
+/*								    */
+/* **************************************************************** */
+
+int
+sh_openpipe (pv)
+     int *pv;
+{
+  int r;
+
+  if ((r = pipe (pv)) < 0)
+    return r;
+
+  pv[0] = move_to_high_fd (pv[0], 1, 64);
+  pv[1] = move_to_high_fd (pv[1], 1, 64);
+
+  return 0;  
+}
+
+int
+sh_closepipe (pv)
+     int *pv;
+{
+  if (pv[0] >= 0)
+    close (pv[0]);
+
+  if (pv[1] >= 0)
+    close (pv[1]);
+
+  pv[0] = pv[1] = -1;
+  return 0;
+}
+
+/* **************************************************************** */
+/*								    */
+/*		    Functions to inspect pathnames		    */
+/*								    */
+/* **************************************************************** */
+
+int
+file_exists (fn)
+     const char *fn;
+{
+  struct stat sb;
+
+  return (stat (fn, &sb) == 0);
+}
+
+int
+file_isdir (fn)
+     const char *fn;
+{
+  struct stat sb;
+
+  return ((stat (fn, &sb) == 0) && S_ISDIR (sb.st_mode));
+}
+
+int
+file_iswdir (fn)
+     const char *fn;
+{
+  return (file_isdir (fn) && sh_eaccess (fn, W_OK) == 0);
+}
+
+/* Return 1 if STRING is "." or "..", optionally followed by a directory
+   separator */
+int
+path_dot_or_dotdot (string)
+     const char *string;
+{
+  if (string == 0 || *string == '\0' || *string != '.')
+    return (0);
+
+  /* string[0] == '.' */
+  if (PATHSEP(string[1]) || (string[1] == '.' && PATHSEP(string[2])))
+    return (1);
+
+  return (0);
+}
+
+/* Return 1 if STRING contains an absolute pathname, else 0.  Used by `cd'
+   to decide whether or not to look up a directory name in $CDPATH. */
+int
+absolute_pathname (string)
+     const char *string;
+{
+  if (string == 0 || *string == '\0')
+    return (0);
+
+  if (ABSPATH(string))
+    return (1);
+
+  if (string[0] == '.' && PATHSEP(string[1]))	/* . and ./ */
+    return (1);
+
+  if (string[0] == '.' && string[1] == '.' && PATHSEP(string[2]))	/* .. and ../ */
+    return (1);
+
+  return (0);
+}
+
+/* Return 1 if STRING is an absolute program name; it is absolute if it
+   contains any slashes.  This is used to decide whether or not to look
+   up through $PATH. */
+int
+absolute_program (string)
+     const char *string;
+{
+  return ((char *)mbschr (string, '/') != (char *)NULL);
+}
+
+/* **************************************************************** */
+/*								    */
+/*		    Functions to manipulate pathnames		    */
+/*								    */
+/* **************************************************************** */
+
+/* Turn STRING (a pathname) into an absolute pathname, assuming that
+   DOT_PATH contains the symbolic location of `.'.  This always
+   returns a new string, even if STRING was an absolute pathname to
+   begin with. */
+char *
+make_absolute (string, dot_path)
+     const char *string, *dot_path;
+{
+  char *result;
+
+  if (dot_path == 0 || ABSPATH(string))
+#ifdef __CYGWIN__
+    {
+      char pathbuf[PATH_MAX + 1];
+
+      /* WAS cygwin_conv_to_full_posix_path (string, pathbuf); */
+      cygwin_conv_path (CCP_WIN_A_TO_POSIX, string, pathbuf, PATH_MAX);
+      result = savestring (pathbuf);
+    }
+#else
+    result = savestring (string);
+#endif
+  else
+    result = sh_makepath (dot_path, string, 0);
+
+  return (result);
+}
+
+/* Return the `basename' of the pathname in STRING (the stuff after the
+   last '/').  If STRING is `/', just return it. */
+char *
+base_pathname (string)
+     char *string;
+{
+  char *p;
+
+#if 0
+  if (absolute_pathname (string) == 0)
+    return (string);
+#endif
+
+  if (string[0] == '/' && string[1] == 0)
+    return (string);
+
+  p = (char *)strrchr (string, '/');
+  return (p ? ++p : string);
+}
+
+/* Return the full pathname of FILE.  Easy.  Filenames that begin
+   with a '/' are returned as themselves.  Other filenames have
+   the current working directory prepended.  A new string is
+   returned in either case. */
+char *
+full_pathname (file)
+     char *file;
+{
+  char *ret;
+
+  file = (*file == '~') ? bash_tilde_expand (file, 0) : savestring (file);
+
+  if (ABSPATH(file))
+    return (file);
+
+  ret = sh_makepath ((char *)NULL, file, (MP_DOCWD|MP_RMDOT));
+  free (file);
+
+  return (ret);
+}
+
+/* A slightly related function.  Get the prettiest name of this
+   directory possible. */
+static char tdir[PATH_MAX];
+
+/* Return a pretty pathname.  If the first part of the pathname is
+   the same as $HOME, then replace that with `~'.  */
+char *
+polite_directory_format (name)
+     char *name;
+{
+  char *home;
+  int l;
+
+  home = get_string_value ("HOME");
+  l = home ? strlen (home) : 0;
+  if (l > 1 && strncmp (home, name, l) == 0 && (!name[l] || name[l] == '/'))
+    {
+      strncpy (tdir + 1, name + l, sizeof(tdir) - 2);
+      tdir[0] = '~';
+      tdir[sizeof(tdir) - 1] = '\0';
+      return (tdir);
+    }
+  else
+    return (name);
+}
+
+/* Trim NAME.  If NAME begins with `~/', skip over tilde prefix.  Trim to
+   keep any tilde prefix and PROMPT_DIRTRIM trailing directory components
+   and replace the intervening characters with `...' */
+char *
+trim_pathname (name, maxlen)
+     char *name;
+     int maxlen;
+{
+  int nlen, ndirs;
+  intmax_t nskip;
+  char *nbeg, *nend, *ntail, *v;
+
+  if (name == 0 || (nlen = strlen (name)) == 0)
+    return name;
+  nend = name + nlen;
+
+  v = get_string_value ("PROMPT_DIRTRIM");
+  if (v == 0 || *v == 0)
+    return name;
+  if (legal_number (v, &nskip) == 0 || nskip <= 0)
+    return name;
+
+  /* Skip over tilde prefix */
+  nbeg = name;
+  if (name[0] == '~')
+    for (nbeg = name; *nbeg; nbeg++)
+      if (*nbeg == '/')
+	{
+	  nbeg++;
+	  break;
+	}
+  if (*nbeg == 0)
+    return name;
+
+  for (ndirs = 0, ntail = nbeg; *ntail; ntail++)
+    if (*ntail == '/')
+      ndirs++;
+  if (ndirs < nskip)
+    return name;
+
+  for (ntail = (*nend == '/') ? nend : nend - 1; ntail > nbeg; ntail--)
+    {
+      if (*ntail == '/')
+	nskip--;
+      if (nskip == 0)
+	break;
+    }
+  if (ntail == nbeg)
+    return name;
+
+  /* Now we want to return name[0..nbeg]+"..."+ntail, modifying name in place */
+  nlen = ntail - nbeg;
+  if (nlen <= 3)
+    return name;
+
+  *nbeg++ = '.';
+  *nbeg++ = '.';
+  *nbeg++ = '.';
+
+  nlen = nend - ntail;
+  memmove (nbeg, ntail, nlen);
+  nbeg[nlen] = '\0';
+
+  return name;
+}
+
+/* Return a printable representation of FN without special characters.  The
+   caller is responsible for freeing memory if this returns something other
+   than its argument.  If FLAGS is non-zero, we are printing for portable
+   re-input and should single-quote filenames appropriately. */
+char *
+printable_filename (fn, flags)
+     char *fn;
+     int flags;
+{
+  char *newf;
+
+  if (ansic_shouldquote (fn))
+    newf = ansic_quote (fn, 0, NULL);
+  else if (flags && sh_contains_shell_metas (fn))
+    newf = sh_single_quote (fn);
+  else
+    newf = fn;
+
+  return newf;
+}
+
+/* Given a string containing units of information separated by colons,
+   return the next one pointed to by (P_INDEX), or NULL if there are no more.
+   Advance (P_INDEX) to the character after the colon. */
+char *
+extract_colon_unit (string, p_index)
+     char *string;
+     int *p_index;
+{
+  int i, start, len;
+  char *value;
+
+  if (string == 0)
+    return (string);
+
+  len = strlen (string);
+  if (*p_index >= len)
+    return ((char *)NULL);
+
+  i = *p_index;
+
+  /* Each call to this routine leaves the index pointing at a colon if
+     there is more to the path.  If I is > 0, then increment past the
+     `:'.  If I is 0, then the path has a leading colon.  Trailing colons
+     are handled OK by the `else' part of the if statement; an empty
+     string is returned in that case. */
+  if (i && string[i] == ':')
+    i++;
+
+  for (start = i; string[i] && string[i] != ':'; i++)
+    ;
+
+  *p_index = i;
+
+  if (i == start)
+    {
+      if (string[i])
+	(*p_index)++;
+      /* Return "" in the case of a trailing `:'. */
+      value = (char *)xmalloc (1);
+      value[0] = '\0';
+    }
+  else
+    value = substring (string, start, i);
+
+  return (value);
+}
+
+/* **************************************************************** */
+/*								    */
+/*		    Tilde Initialization and Expansion		    */
+/*								    */
+/* **************************************************************** */
+
+#if defined (PUSHD_AND_POPD)
+extern char *get_dirstack_from_string PARAMS((char *));
+#endif
+
+static char **bash_tilde_prefixes;
+static char **bash_tilde_prefixes2;
+static char **bash_tilde_suffixes;
+static char **bash_tilde_suffixes2;
+
+/* If tilde_expand hasn't been able to expand the text, perhaps it
+   is a special shell expansion.  This function is installed as the
+   tilde_expansion_preexpansion_hook.  It knows how to expand ~- and ~+.
+   If PUSHD_AND_POPD is defined, ~[+-]N expands to directories from the
+   directory stack. */
+static char *
+bash_special_tilde_expansions (text)
+     char *text;
+{
+  char *result;
+
+  result = (char *)NULL;
+
+  if (text[0] == '+' && text[1] == '\0')
+    result = get_string_value ("PWD");
+  else if (text[0] == '-' && text[1] == '\0')
+    result = get_string_value ("OLDPWD");
+#if defined (PUSHD_AND_POPD)
+  else if (DIGIT (*text) || ((*text == '+' || *text == '-') && DIGIT (text[1])))
+    result = get_dirstack_from_string (text);
+#endif
+
+  return (result ? savestring (result) : (char *)NULL);
+}
+
+/* Initialize the tilde expander.  In Bash, we handle `~-' and `~+', as
+   well as handling special tilde prefixes; `:~" and `=~' are indications
+   that we should do tilde expansion. */
+void
+tilde_initialize ()
+{
+  static int times_called = 0;
+
+  /* Tell the tilde expander that we want a crack first. */
+  tilde_expansion_preexpansion_hook = bash_special_tilde_expansions;
+
+  /* Tell the tilde expander about special strings which start a tilde
+     expansion, and the special strings that end one.  Only do this once.
+     tilde_initialize () is called from within bashline_reinitialize (). */
+  if (times_called++ == 0)
+    {
+      bash_tilde_prefixes = strvec_create (3);
+      bash_tilde_prefixes[0] = "=~";
+      bash_tilde_prefixes[1] = ":~";
+      bash_tilde_prefixes[2] = (char *)NULL;
+
+      bash_tilde_prefixes2 = strvec_create (2);
+      bash_tilde_prefixes2[0] = ":~";
+      bash_tilde_prefixes2[1] = (char *)NULL;
+
+      tilde_additional_prefixes = bash_tilde_prefixes;
+
+      bash_tilde_suffixes = strvec_create (3);
+      bash_tilde_suffixes[0] = ":";
+      bash_tilde_suffixes[1] = "=~";	/* XXX - ?? */
+      bash_tilde_suffixes[2] = (char *)NULL;
+
+      tilde_additional_suffixes = bash_tilde_suffixes;
+
+      bash_tilde_suffixes2 = strvec_create (2);
+      bash_tilde_suffixes2[0] = ":";
+      bash_tilde_suffixes2[1] = (char *)NULL;
+    }
+}
+
+/* POSIX.2, 3.6.1:  A tilde-prefix consists of an unquoted tilde character
+   at the beginning of the word, followed by all of the characters preceding
+   the first unquoted slash in the word, or all the characters in the word
+   if there is no slash...If none of the characters in the tilde-prefix are
+   quoted, the characters in the tilde-prefix following the tilde shell be
+   treated as a possible login name. */
+
+#define TILDE_END(c)	((c) == '\0' || (c) == '/' || (c) == ':')
+
+static int
+unquoted_tilde_word (s)
+     const char *s;
+{
+  const char *r;
+
+  for (r = s; TILDE_END(*r) == 0; r++)
+    {
+      switch (*r)
+	{
+	case '\\':
+	case '\'':
+	case '"':
+	  return 0;
+	}
+    }
+  return 1;
+}
+
+/* Find the end of the tilde-prefix starting at S, and return the tilde
+   prefix in newly-allocated memory.  Return the length of the string in
+   *LENP.  FLAGS tells whether or not we're in an assignment context --
+   if so, `:' delimits the end of the tilde prefix as well. */
+char *
+bash_tilde_find_word (s, flags, lenp)
+     const char *s;
+     int flags, *lenp;
+{
+  const char *r;
+  char *ret;
+  int l;
+
+  for (r = s; *r && *r != '/'; r++)
+    {
+      /* Short-circuit immediately if we see a quote character.  Even though
+	 POSIX says that `the first unquoted slash' (or `:') terminates the
+	 tilde-prefix, in practice, any quoted portion of the tilde prefix
+	 will cause it to not be expanded. */
+      if (*r == '\\' || *r == '\'' || *r == '"')  
+	{
+	  ret = savestring (s);
+	  if (lenp)
+	    *lenp = 0;
+	  return ret;
+	}
+      else if (flags && *r == ':')
+	break;
+    }
+  l = r - s;
+  ret = xmalloc (l + 1);
+  strncpy (ret, s, l);
+  ret[l] = '\0';
+  if (lenp)
+    *lenp = l;
+  return ret;
+}
+    
+/* Tilde-expand S by running it through the tilde expansion library.
+   ASSIGN_P is 1 if this is a variable assignment, so the alternate
+   tilde prefixes should be enabled (`=~' and `:~', see above).  If
+   ASSIGN_P is 2, we are expanding the rhs of an assignment statement,
+   so `=~' is not valid. */
+char *
+bash_tilde_expand (s, assign_p)
+     const char *s;
+     int assign_p;
+{
+  int r;
+  char *ret;
+
+  tilde_additional_prefixes = assign_p == 0 ? (char **)0
+  					    : (assign_p == 2 ? bash_tilde_prefixes2 : bash_tilde_prefixes);
+  if (assign_p == 2)
+    tilde_additional_suffixes = bash_tilde_suffixes2;
+
+  r = (*s == '~') ? unquoted_tilde_word (s) : 1;
+  ret = r ? tilde_expand (s) : savestring (s);
+
+  QUIT;
+
+  return (ret);
+}
+
+/* **************************************************************** */
+/*								    */
+/*	  Functions to manipulate and search the group list	    */
+/*								    */
+/* **************************************************************** */
+
+static int ngroups, maxgroups;
+
+/* The set of groups that this user is a member of. */
+static GETGROUPS_T *group_array = (GETGROUPS_T *)NULL;
+
+#if !defined (NOGROUP)
+#  define NOGROUP (gid_t) -1
+#endif
+
+static void
+initialize_group_array ()
+{
+  register int i;
+
+  if (maxgroups == 0)
+    maxgroups = getmaxgroups ();
+
+  ngroups = 0;
+  group_array = (GETGROUPS_T *)xrealloc (group_array, maxgroups * sizeof (GETGROUPS_T));
+
+#if defined (HAVE_GETGROUPS)
+  ngroups = getgroups (maxgroups, group_array);
+#endif
+
+  /* If getgroups returns nothing, or the OS does not support getgroups(),
+     make sure the groups array includes at least the current gid. */
+  if (ngroups == 0)
+    {
+      group_array[0] = current_user.gid;
+      ngroups = 1;
+    }
+
+  /* If the primary group is not in the groups array, add it as group_array[0]
+     and shuffle everything else up 1, if there's room. */
+  for (i = 0; i < ngroups; i++)
+    if (current_user.gid == (gid_t)group_array[i])
+      break;
+  if (i == ngroups && ngroups < maxgroups)
+    {
+      for (i = ngroups; i > 0; i--)
+	group_array[i] = group_array[i - 1];
+      group_array[0] = current_user.gid;
+      ngroups++;
+    }
+
+  /* If the primary group is not group_array[0], swap group_array[0] and
+     whatever the current group is.  The vast majority of systems should
+     not need this; a notable exception is Linux. */
+  if (group_array[0] != current_user.gid)
+    {
+      for (i = 0; i < ngroups; i++)
+	if (group_array[i] == current_user.gid)
+	  break;
+      if (i < ngroups)
+	{
+	  group_array[i] = group_array[0];
+	  group_array[0] = current_user.gid;
+	}
+    }
+}
+
+/* Return non-zero if GID is one that we have in our groups list. */
+int
+#if defined (__STDC__) || defined ( _MINIX)
+group_member (gid_t gid)
+#else
+group_member (gid)
+     gid_t gid;
+#endif /* !__STDC__ && !_MINIX */
+{
+#if defined (HAVE_GETGROUPS)
+  register int i;
+#endif
+
+  /* Short-circuit if possible, maybe saving a call to getgroups(). */
+  if (gid == current_user.gid || gid == current_user.egid)
+    return (1);
+
+#if defined (HAVE_GETGROUPS)
+  if (ngroups == 0)
+    initialize_group_array ();
+
+  /* In case of error, the user loses. */
+  if (ngroups <= 0)
+    return (0);
+
+  /* Search through the list looking for GID. */
+  for (i = 0; i < ngroups; i++)
+    if (gid == (gid_t)group_array[i])
+      return (1);
+#endif
+
+  return (0);
+}
+
+char **
+get_group_list (ngp)
+     int *ngp;
+{
+  static char **group_vector = (char **)NULL;
+  register int i;
+
+  if (group_vector)
+    {
+      if (ngp)
+	*ngp = ngroups;
+      return group_vector;
+    }
+
+  if (ngroups == 0)
+    initialize_group_array ();
+
+  if (ngroups <= 0)
+    {
+      if (ngp)
+	*ngp = 0;
+      return (char **)NULL;
+    }
+
+  group_vector = strvec_create (ngroups);
+  for (i = 0; i < ngroups; i++)
+    group_vector[i] = itos (group_array[i]);
+
+  if (ngp)
+    *ngp = ngroups;
+  return group_vector;
+}
+
+int *
+get_group_array (ngp)
+     int *ngp;
+{
+  int i;
+  static int *group_iarray = (int *)NULL;
+
+  if (group_iarray)
+    {
+      if (ngp)
+	*ngp = ngroups;
+      return (group_iarray);
+    }
+
+  if (ngroups == 0)
+    initialize_group_array ();    
+
+  if (ngroups <= 0)
+    {
+      if (ngp)
+	*ngp = 0;
+      return (int *)NULL;
+    }
+
+  group_iarray = (int *)xmalloc (ngroups * sizeof (int));
+  for (i = 0; i < ngroups; i++)
+    group_iarray[i] = (int)group_array[i];
+
+  if (ngp)
+    *ngp = ngroups;
+  return group_iarray;
+}
+
+/* **************************************************************** */
+/*								    */
+/*	  Miscellaneous functions				    */
+/*								    */
+/* **************************************************************** */
+
+/* Return a value for PATH that is guaranteed to find all of the standard
+   utilities.  This uses Posix.2 configuration variables, if present.  It
+   uses a value defined in config.h as a last resort. */
+char *
+conf_standard_path ()
+{
+#if defined (_CS_PATH) && defined (HAVE_CONFSTR)
+  char *p;
+  size_t len;
+
+  len = (size_t)confstr (_CS_PATH, (char *)NULL, (size_t)0);
+  if (len > 0)
+    {
+      p = (char *)xmalloc (len + 2);
+      *p = '\0';
+      confstr (_CS_PATH, p, len);
+      return (p);
+    }
+  else
+    return (savestring (STANDARD_UTILS_PATH));
+#else /* !_CS_PATH || !HAVE_CONFSTR  */
+#  if defined (CS_PATH)
+  return (savestring (CS_PATH));
+#  else
+  return (savestring (STANDARD_UTILS_PATH));
+#  endif /* !CS_PATH */
+#endif /* !_CS_PATH || !HAVE_CONFSTR */
+}
+
+int
+default_columns ()
+{
+  char *v;
+  int c;
+
+  c = -1;
+  v = get_string_value ("COLUMNS");
+  if (v && *v)
+    {
+      c = atoi (v);
+      if (c > 0)
+	return c;
+    }
+
+  if (check_window_size)
+    get_new_window_size (0, (int *)0, &c);
+
+  return (c > 0 ? c : 80);
+}
+
+