X-Git-Url: https://git.dogcows.com/gitweb?a=blobdiff_plain;f=src%2Fmisc.c;h=b8ef6eabf1ae16e43b1fece6d948b7bf0bc65b76;hb=e3d28d84bda24a45c239b398e7b42ccd9be2d0c2;hp=d75890e00db0eed254815be0773fc1b2d53a8be6;hpb=3728196fa69fb0908f5c175d750978d1423b8340;p=chaz%2Ftar

diff --git a/src/misc.c b/src/misc.c
index d75890e..b8ef6ea 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -1,9 +1,11 @@
 /* Miscellaneous functions, not really specific to GNU tar.
-   Copyright (C) 1988, 92, 94, 95, 96, 97 Free Software Foundation, Inc.
+
+   Copyright 1988, 1992, 1994-1997, 1999-2001, 2003-2007, 2009-2010,
+   2012-2013 Free Software Foundation, Inc.
 
    This program 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 2, or (at your option) any later
+   Free Software Foundation; either version 3, or (at your option) any later
    version.
 
    This program is distributed in the hope that it will be useful, but
@@ -12,120 +14,80 @@
    Public License for more details.
 
    You should have received a copy of the GNU General Public License along
-   with this program; if not, write to the Free Software Foundation, Inc.,
-   59 Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#include "system.h"
+#define COMMON_INLINE _GL_EXTERN_INLINE
+#include <system.h>
+#include <rmt.h>
+#include "common.h"
+#include <quotearg.h>
+#include <xgetcwd.h>
+#include <unlinkdir.h>
+#include <utimens.h>
 
-#include "backupfile.h"
-#include "rmt.h"
+#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
+# define DOUBLE_SLASH_IS_DISTINCT_ROOT 0
+#endif
 
-/* The following inclusion for crosschecking prototypes, only.  */
-#include "common.h"
 
 /* Handling strings.  */
 
-#define ISPRINT(Char) (ISASCII (Char) && isprint (Char))
-
-/*-------------------------------------------------------------------------.
-| Assign STRING to a copy of VALUE if not NULL, or to NULL.  If STRING was |
-| not NULL, it is freed first.						   |
-`-------------------------------------------------------------------------*/
-
+/* Assign STRING to a copy of VALUE if not zero, or to zero.  If
+   STRING was nonzero, it is freed first.  */
 void
 assign_string (char **string, const char *value)
 {
-  if (*string)
-    free (*string);
-  *string = value ? xstrdup (value) : NULL;
+  free (*string);
+  *string = value ? xstrdup (value) : 0;
 }
 
-/*------------------------------------------------------------------------.
-| Allocate a copy of the string quoted as in C, and returns that.  If the |
-| string does not have to be quoted, it returns the NULL string.  The	  |
-| allocated copy should normally be freed with free() after the caller is |
-| done with it.								  |
-| 									  |
-| This is used in two contexts only: either listing a tar file for the	  |
-| --list (-t) option, or generating the directory file in incremental	  |
-| dumps.								  |
-`------------------------------------------------------------------------*/
-
-char *
+#if 0
+/* This function is currently unused; perhaps it should be removed?  */
+
+/* Allocate a copy of the string quoted as in C, and returns that.  If
+   the string does not have to be quoted, it returns a null pointer.
+   The allocated copy should normally be freed with free() after the
+   caller is done with it.
+
+   This is used in one context only: generating the directory file in
+   incremental dumps.  The quoted string is not intended for human
+   consumption; it is intended only for unquote_string.  The quoting
+   is locale-independent, so that users needn't worry about locale
+   when reading directory files.  This means that we can't use
+   quotearg, as quotearg is locale-dependent and is meant for human
+   consumption.  */
+static char *
 quote_copy_string (const char *string)
 {
   const char *source = string;
-  char *destination = NULL;
-  char *buffer = NULL;
+  char *destination = 0;
+  char *buffer = 0;
   int copying = 0;
 
   while (*source)
     {
-      int character = (unsigned char) *source++;
+      int character = *source++;
 
-      if (character == '\\')
+      switch (character)
 	{
+	case '\n': case '\\':
 	  if (!copying)
 	    {
-	      int length = (source - string) - 1;
+	      size_t length = (source - string) - 1;
 
 	      copying = 1;
-	      buffer = (char *) xmalloc (length + 5 + strlen (source) * 4);
-	      memcpy (buffer, string, (size_t) length);
+	      buffer = xmalloc (length + 2 + 2 * strlen (source) + 1);
+	      memcpy (buffer, string, length);
 	      destination = buffer + length;
 	    }
 	  *destination++ = '\\';
-	  *destination++ = '\\';
-	}
-      else if (ISPRINT (character))
-	{
+	  *destination++ = character == '\\' ? '\\' : 'n';
+	  break;
+
+	default:
 	  if (copying)
 	    *destination++ = character;
-	}
-      else
-	{
-	  if (!copying)
-	    {
-	      int length = (source - string) - 1;
-
-	      copying = 1;
-	      buffer = (char *) xmalloc (length + 5 + strlen (source) * 4);
-	      memcpy (buffer, string, (size_t) length);
-	      destination = buffer + length;
-	    }
-	  *destination++ = '\\';
-	  switch (character)
-	    {
-	    case '\n':
-	      *destination++ = 'n';
-	      break;
-
-	    case '\t':
-	      *destination++ = 't';
-	      break;
-
-	    case '\f':
-	      *destination++ = 'f';
-	      break;
-
-	    case '\b':
-	      *destination++ = 'b';
-	      break;
-
-	    case '\r':
-	      *destination++ = 'r';
-	      break;
-
-	    case '\177':
-	      *destination++ = '?';
-	      break;
-
-	    default:
-	      *destination++ = (character >> 6) + '0';
-	      *destination++ = ((character >> 3) & 07) + '0';
-	      *destination++ = (character & 07) + '0';
-	      break;
-	    }
+	  break;
 	}
     }
   if (copying)
@@ -133,21 +95,20 @@ quote_copy_string (const char *string)
       *destination = '\0';
       return buffer;
     }
-  return NULL;
+  return 0;
 }
+#endif
 
-/*-------------------------------------------------------------------------.
-| Takes a quoted C string (like those produced by quote_copy_string) and   |
-| turns it back into the un-quoted original.  This is done in place.	   |
-| Returns 0 only if the string was not properly quoted, but completes the  |
-| unquoting anyway.							   |
-| 									   |
-| This is used for reading the saved directory file in incremental dumps.  |
-| It is used for decoding old `N' records (demangling names).  But also,   |
-| it is used for decoding file arguments, would they come from the shell   |
-| or a -T file, and for decoding the --exclude argument.		   |
-`-------------------------------------------------------------------------*/
+/* Takes a quoted C string (like those produced by quote_copy_string)
+   and turns it back into the un-quoted original.  This is done in
+   place.  Returns 0 only if the string was not properly quoted, but
+   completes the unquoting anyway.
 
+   This is used for reading the saved directory file in incremental
+   dumps.  It is used for decoding old 'N' records (demangling names).
+   But also, it is used for decoding file arguments, would they come
+   from the shell or a -T file, and for decoding the --exclude
+   argument.  */
 int
 unquote_string (char *string)
 {
@@ -155,6 +116,11 @@ unquote_string (char *string)
   char *source = string;
   char *destination = string;
 
+  /* Escape sequences other than \\ and \n are no longer generated by
+     quote_copy_string, but accept them for backwards compatibility,
+     and also because unquote_string is used for purposes other than
+     parsing the output of quote_copy_string.  */
+
   while (*source)
     if (*source == '\\')
       switch (*++source)
@@ -164,13 +130,13 @@ unquote_string (char *string)
 	  source++;
 	  break;
 
-	case 'n':
-	  *destination++ = '\n';
+	case 'a':
+	  *destination++ = '\a';
 	  source++;
 	  break;
 
-	case 't':
-	  *destination++ = '\t';
+	case 'b':
+	  *destination++ = '\b';
 	  source++;
 	  break;
 
@@ -179,8 +145,8 @@ unquote_string (char *string)
 	  source++;
 	  break;
 
-	case 'b':
-	  *destination++ = '\b';
+	case 'n':
+	  *destination++ = '\n';
 	  source++;
 	  break;
 
@@ -189,6 +155,16 @@ unquote_string (char *string)
 	  source++;
 	  break;
 
+	case 't':
+	  *destination++ = '\t';
+	  source++;
+	  break;
+
+	case 'v':
+	  *destination++ = '\v';
+	  source++;
+	  break;
+
 	case '?':
 	  *destination++ = 0177;
 	  source++;
@@ -237,245 +213,1001 @@ unquote_string (char *string)
     *destination = '\0';
   return result;
 }
-
-/* Sorting lists.  */
 
-/*---.
-| ?  |
-`---*/
+/* Zap trailing slashes.  */
+char *
+zap_slashes (char *name)
+{
+  char *q;
+
+  if (!name || *name == 0)
+    return name;
+  q = name + strlen (name) - 1;
+  while (q > name && ISSLASH (*q))
+    *q-- = '\0';
+  return name;
+}
+
+/* Normalize FILE_NAME by removing redundant slashes and "."
+   components, including redundant trailing slashes.  Leave ".."
+   alone, as it may be significant in the presence of symlinks and on
+   platforms where "/.." != "/".  Destructive version: modifies its
+   argument. */
+static void
+normalize_filename_x (char *file_name)
+{
+  char *name = file_name + FILE_SYSTEM_PREFIX_LEN (file_name);
+  char *p;
+  char const *q;
+  char c;
+
+  /* Don't squeeze leading "//" to "/", on hosts where they're distinct.  */
+  name += (DOUBLE_SLASH_IS_DISTINCT_ROOT
+	   && ISSLASH (*name) && ISSLASH (name[1]) && ! ISSLASH (name[2]));
+
+  /* Omit redundant leading "." components.  */
+  for (q = p = name; (*p = *q) == '.' && ISSLASH (q[1]); p += !*q)
+    for (q += 2; ISSLASH (*q); q++)
+      continue;
+
+  /* Copy components from Q to P, omitting redundant slashes and
+     internal "."  components.  */
+  while ((*p++ = c = *q++) != '\0')
+    if (ISSLASH (c))
+      while (ISSLASH (q[*q == '.']))
+	q += (*q == '.') + 1;
+
+  /* Omit redundant trailing "." component and slash.  */
+  if (2 < p - name)
+    {
+      p -= p[-2] == '.' && ISSLASH (p[-3]);
+      p -= 2 < p - name && ISSLASH (p[-2]);
+      p[-1] = '\0';
+    }
+}
+
+/* Normalize NAME by removing redundant slashes and "." components,
+   including redundant trailing slashes.  Return a normalized
+   newly-allocated copy.  */
 
 char *
-merge_sort (char *list, int length, int offset, int (*compare) (char *, char *))
+normalize_filename (const char *name)
 {
-  char *first_list;
-  char *second_list;
-  int first_length;
-  int second_length;
-  char *result;
-  char **merge_point;
-  char *cursor;
-  int counter;
+  char *copy = NULL;
 
-#define SUCCESSOR(Pointer) \
-  (*((char **) (((char *) (Pointer)) + offset)))
+  if (IS_RELATIVE_FILE_NAME (name))
+    {
+      /* Set COPY to the absolute file name if possible.
+
+         FIXME: There should be no need to get the absolute file name.
+         getcwd is slow, it might fail, and it does not necessarily
+         return a canonical name even when it succeeds.  Perhaps we
+         can use dev+ino pairs instead of names?  */
+      copy = tar_getcwd ();
+      if (copy)
+        {
+          size_t copylen = strlen (copy);
+          bool need_separator = ! (DOUBLE_SLASH_IS_DISTINCT_ROOT
+                                   && copylen == 2 && ISSLASH (copy[1]));
+          copy = xrealloc (copy, copylen + need_separator + strlen (name) + 1);
+          copy[copylen] = DIRECTORY_SEPARATOR;
+          strcpy (copy + copylen + need_separator, name);
+        }
+      else
+        WARN ((0, errno, _("Cannot get working directory")));
+    }
 
-  if (length == 1)
-    return list;
+  if (! copy)
+    copy = xstrdup (name);
+  normalize_filename_x (copy);
+  return copy;
+}
 
-  if (length == 2)
+
+void
+replace_prefix (char **pname, const char *samp, size_t slen,
+		const char *repl, size_t rlen)
+{
+  char *name = *pname;
+  size_t nlen = strlen (name);
+  if (nlen > slen && memcmp (name, samp, slen) == 0 && ISSLASH (name[slen]))
     {
-      if ((*compare) (list, SUCCESSOR (list)) > 0)
+      if (rlen > slen)
 	{
-	  result = SUCCESSOR (list);
-	  SUCCESSOR (result) = list;
-	  SUCCESSOR (list) = NULL;
-	  return result;
+	  name = xrealloc (name, nlen - slen + rlen + 1);
+	  *pname = name;
 	}
-      return list;
+      memmove (name + rlen, name + slen, nlen - slen + 1);
+      memcpy (name, repl, rlen);
     }
+}
 
-  first_list = list;
-  first_length = (length + 1) / 2;
-  second_length = length / 2;
-  for (cursor = list, counter = first_length - 1;
-       counter;
-       cursor = SUCCESSOR (cursor), counter--)
-    continue;
-  second_list = SUCCESSOR (cursor);
-  SUCCESSOR (cursor) = NULL;
-
-  first_list = merge_sort (first_list, first_length, offset, compare);
-  second_list = merge_sort (second_list, second_length, offset, compare);
-
-  merge_point = &result;
-  while (first_list && second_list)
-    if ((*compare) (first_list, second_list) < 0)
-      {
-	cursor = SUCCESSOR (first_list);
-	*merge_point = first_list;
-	merge_point = &SUCCESSOR (first_list);
-	first_list = cursor;
-      }
-    else
-      {
-	cursor = SUCCESSOR (second_list);
-	*merge_point = second_list;
-	merge_point = &SUCCESSOR (second_list);
-	second_list = cursor;
-      }
-  if (first_list)
-    *merge_point = first_list;
+
+/* Handling numbers.  */
+
+/* Convert VALUE, which is converted from a system integer type whose
+   minimum value is MINVAL and maximum MINVAL, to an decimal
+   integer string.  Use the storage in BUF and return a pointer to the
+   converted string.  If VALUE is converted from a negative integer in
+   the range MINVAL .. -1, represent it with a string representation
+   of the negative integer, using leading '-'.  */
+#if ! (INTMAX_MAX <= UINTMAX_MAX / 2)
+# error "sysinttostr: uintmax_t cannot represent all intmax_t values"
+#endif
+char *
+sysinttostr (uintmax_t value, intmax_t minval, uintmax_t maxval,
+	     char buf[SYSINT_BUFSIZE])
+{
+  if (value <= maxval)
+    return umaxtostr (value, buf);
   else
-    *merge_point = second_list;
+    {
+      intmax_t i = value - minval;
+      return imaxtostr (i + minval, buf);
+    }
+}
 
-  return result;
+/* Convert a prefix of the string ARG to a system integer type whose
+   minimum value is MINVAL and maximum MAXVAL.  If MINVAL is negative,
+   negative integers MINVAL .. -1 are assumed to be represented using
+   leading '-' in the usual way.  If the represented value exceeds
+   INTMAX_MAX, return a negative integer V such that (uintmax_t) V
+   yields the represented value.  If ARGLIM is nonnull, store into
+   *ARGLIM a pointer to the first character after the prefix.
+
+   This is the inverse of sysinttostr.
+
+   On a normal return, set errno = 0.
+   On conversion error, return 0 and set errno = EINVAL.
+   On overflow, return an extreme value and set errno = ERANGE.  */
+#if ! (INTMAX_MAX <= UINTMAX_MAX)
+# error "strtosysint: nonnegative intmax_t does not fit in uintmax_t"
+#endif
+intmax_t
+strtosysint (char const *arg, char **arglim, intmax_t minval, uintmax_t maxval)
+{
+  errno = 0;
+  if (maxval <= INTMAX_MAX)
+    {
+      if (ISDIGIT (arg[*arg == '-']))
+	{
+	  intmax_t i = strtoimax (arg, arglim, 10);
+	  intmax_t imaxval = maxval;
+	  if (minval <= i && i <= imaxval)
+	    return i;
+	  errno = ERANGE;
+	  return i < minval ? minval : maxval;
+	}
+    }
+  else
+    {
+      if (ISDIGIT (*arg))
+	{
+	  uintmax_t i = strtoumax (arg, arglim, 10);
+	  if (i <= maxval)
+	    return represent_uintmax (i);
+	  errno = ERANGE;
+	  return maxval;
+	}
+    }
+
+  errno = EINVAL;
+  return 0;
+}
+
+/* Output fraction and trailing digits appropriate for a nanoseconds
+   count equal to NS, but don't output unnecessary '.' or trailing
+   zeros.  */
+
+void
+code_ns_fraction (int ns, char *p)
+{
+  if (ns == 0)
+    *p = '\0';
+  else
+    {
+      int i = 9;
+      *p++ = '.';
+
+      while (ns % 10 == 0)
+	{
+	  ns /= 10;
+	  i--;
+	}
+
+      p[i] = '\0';
+
+      for (;;)
+	{
+	  p[--i] = '0' + ns % 10;
+	  if (i == 0)
+	    break;
+	  ns /= 10;
+	}
+    }
+}
+
+char const *
+code_timespec (struct timespec t, char sbuf[TIMESPEC_STRSIZE_BOUND])
+{
+  time_t s = t.tv_sec;
+  int ns = t.tv_nsec;
+  char *np;
+  bool negative = s < 0;
+
+  /* ignore invalid values of ns */
+  if (BILLION <= ns || ns < 0)
+    ns = 0;
+
+  if (negative && ns != 0)
+    {
+      s++;
+      ns = BILLION - ns;
+    }
+
+  np = umaxtostr (negative ? - (uintmax_t) s : (uintmax_t) s, sbuf + 1);
+  if (negative)
+    *--np = '-';
+  code_ns_fraction (ns, sbuf + UINTMAX_STRSIZE_BOUND);
+  return np;
+}
+
+struct timespec
+decode_timespec (char const *arg, char **arg_lim, bool parse_fraction)
+{
+  time_t s = TYPE_MINIMUM (time_t);
+  int ns = -1;
+  char const *p = arg;
+  bool negative = *arg == '-';
+  struct timespec r;
+
+  if (! ISDIGIT (arg[negative]))
+    errno = EINVAL;
+  else
+    {
+      errno = 0;
+
+      if (negative)
+	{
+	  intmax_t i = strtoimax (arg, arg_lim, 10);
+	  if (TYPE_SIGNED (time_t) ? TYPE_MINIMUM (time_t) <= i : 0 <= i)
+	    s = i;
+	  else
+	    errno = ERANGE;
+	}
+      else
+	{
+	  uintmax_t i = strtoumax (arg, arg_lim, 10);
+	  if (i <= TYPE_MAXIMUM (time_t))
+	    s = i;
+	  else
+	    errno = ERANGE;
+	}
+
+      p = *arg_lim;
+      ns = 0;
+
+      if (parse_fraction && *p == '.')
+	{
+	  int digits = 0;
+	  bool trailing_nonzero = false;
+
+	  while (ISDIGIT (*++p))
+	    if (digits < LOG10_BILLION)
+	      digits++, ns = 10 * ns + (*p - '0');
+	    else
+	      trailing_nonzero |= *p != '0';
 
-#undef SUCCESSOR
+	  while (digits < LOG10_BILLION)
+	    digits++, ns *= 10;
+
+	  if (negative)
+	    {
+	      /* Convert "-1.10000000000001" to s == -2, ns == 89999999.
+		 I.e., truncate time stamps towards minus infinity while
+		 converting them to internal form.  */
+	      ns += trailing_nonzero;
+	      if (ns != 0)
+		{
+		  if (s == TYPE_MINIMUM (time_t))
+		    ns = -1;
+		  else
+		    {
+		      s--;
+		      ns = BILLION - ns;
+		    }
+		}
+	    }
+	}
+
+      if (errno == ERANGE)
+	ns = -1;
+    }
+
+  *arg_lim = (char *) p;
+  r.tv_sec = s;
+  r.tv_nsec = ns;
+  return r;
 }
 
 /* File handling.  */
 
 /* Saved names in case backup needs to be undone.  */
-static char *before_backup_name = NULL;
-static char *after_backup_name = NULL;
+static char *before_backup_name;
+static char *after_backup_name;
+
+/* Return 1 if FILE_NAME is obviously "." or "/".  */
+bool
+must_be_dot_or_slash (char const *file_name)
+{
+  file_name += FILE_SYSTEM_PREFIX_LEN (file_name);
 
-/*------------------------------------------------------------------------.
-| Returns nonzero if p is `.' or `..'.  This could be a macro for speed.  |
-`------------------------------------------------------------------------*/
+  if (ISSLASH (file_name[0]))
+    {
+      for (;;)
+	if (ISSLASH (file_name[1]))
+	  file_name++;
+	else if (file_name[1] == '.'
+                 && ISSLASH (file_name[2 + (file_name[2] == '.')]))
+	  file_name += 2 + (file_name[2] == '.');
+	else
+	  return ! file_name[1];
+    }
+  else
+    {
+      while (file_name[0] == '.' && ISSLASH (file_name[1]))
+	{
+	  file_name += 2;
+	  while (ISSLASH (*file_name))
+	    file_name++;
+	}
 
-/* Early Solaris 2.4 readdir may return d->d_name as `' in NFS-mounted
-   directories.  The workaround here skips `' just like `.'.  Without it,
-   GNU tar would then treat `' much like `.' and loop endlessly.  */
+      return ! file_name[0] || (file_name[0] == '.' && ! file_name[1]);
+    }
+}
 
-int
-is_dot_or_dotdot (const char *p)
+/* Some implementations of rmdir let you remove '.' or '/'.
+   Report an error with errno set to zero for obvious cases of this;
+   otherwise call rmdir.  */
+static int
+safer_rmdir (const char *file_name)
 {
-  return (p[0] == '\0'
-	  || (p[0] == '.' && (p[1] == '\0'
-			      || (p[1] == '.' && p[2] == '\0'))));
-}
+  if (must_be_dot_or_slash (file_name))
+    {
+      errno = 0;
+      return -1;
+    }
 
-/*-------------------------------------------------------------------------.
-| Delete PATH, whatever it might be.  If RECURSE, first recursively delete |
-| the contents of PATH when it is a directory.  Return zero on any error,  |
-| with errno set.  As a special case, if we fail to delete a directory	   |
-| when not RECURSE, do not set errno (just be tolerant to this error).	   |
-`-------------------------------------------------------------------------*/
+  return unlinkat (chdir_fd, file_name, AT_REMOVEDIR);
+}
 
+/* Remove FILE_NAME, returning 1 on success.  If FILE_NAME is a directory,
+   then if OPTION is RECURSIVE_REMOVE_OPTION is set remove FILE_NAME
+   recursively; otherwise, remove it only if it is empty.  If FILE_NAME is
+   a directory that cannot be removed (e.g., because it is nonempty)
+   and if OPTION is WANT_DIRECTORY_REMOVE_OPTION, then return -1.
+   Return 0 on error, with errno set; if FILE_NAME is obviously the working
+   directory return zero with errno set to zero.  */
 int
-remove_any_file (const char *path, int recurse)
+remove_any_file (const char *file_name, enum remove_option option)
 {
-  struct stat stat_buffer;
+  /* Try unlink first if we cannot unlink directories, as this saves
+     us a system call in the common case where we're removing a
+     non-directory.  */
+  bool try_unlink_first = cannot_unlink_dir ();
 
-  if (lstat (path, &stat_buffer) < 0)
-    return 0;
+  if (try_unlink_first)
+    {
+      if (unlinkat (chdir_fd, file_name, 0) == 0)
+	return 1;
+
+      /* POSIX 1003.1-2001 requires EPERM when attempting to unlink a
+	 directory without appropriate privileges, but many Linux
+	 kernels return the more-sensible EISDIR.  */
+      if (errno != EPERM && errno != EISDIR)
+	return 0;
+    }
+
+  if (safer_rmdir (file_name) == 0)
+    return 1;
 
-  if (S_ISDIR (stat_buffer.st_mode))
-    if (recurse)
-      {
-	DIR *dirp = opendir (path);
-	struct dirent *dp;
+  switch (errno)
+    {
+    case ENOTDIR:
+      return !try_unlink_first && unlinkat (chdir_fd, file_name, 0) == 0;
+
+    case 0:
+    case EEXIST:
+#if defined ENOTEMPTY && ENOTEMPTY != EEXIST
+    case ENOTEMPTY:
+#endif
+      switch (option)
+	{
+	case ORDINARY_REMOVE_OPTION:
+	  break;
 
-	if (dirp == NULL)
-	  return 0;
+	case WANT_DIRECTORY_REMOVE_OPTION:
+	  return -1;
 
-	while (dp = readdir (dirp), dp && !is_dot_or_dotdot (dp->d_name))
+	case RECURSIVE_REMOVE_OPTION:
 	  {
-	    char *path_buffer = new_name (path, dp->d_name);
+	    char *directory = tar_savedir (file_name, 0);
+	    char const *entry;
+	    size_t entrylen;
 
-	    if (!remove_any_file (path_buffer, 1))
-	      {
-		int saved_errno = errno;
+	    if (! directory)
+	      return 0;
 
-		free (path_buffer);
-		closedir (dirp);
-		errno = saved_errno; /* FIXME: errno should be read-only */
-		return 0;
+	    for (entry = directory;
+		 (entrylen = strlen (entry)) != 0;
+		 entry += entrylen + 1)
+	      {
+		char *file_name_buffer = new_name (file_name, entry);
+		int r = remove_any_file (file_name_buffer,
+                                         RECURSIVE_REMOVE_OPTION);
+		int e = errno;
+		free (file_name_buffer);
+
+		if (! r)
+		  {
+		    free (directory);
+		    errno = e;
+		    return 0;
+		  }
 	      }
-	    free (path_buffer);
+
+	    free (directory);
+	    return safer_rmdir (file_name) == 0;
 	  }
-	closedir (dirp);
-	return rmdir (path) >= 0;
-      }
-    else
-      {
-	/* FIXME: Saving errno might not be needed anymore, now that
-	   extract_archive tests for the special case before recovery.  */
-	int saved_errno = errno;
-
-	if (rmdir (path) >= 0)
-	  return 1;
-	errno = saved_errno;	/* FIXME: errno should be read-only */
-	return 0;
-      }
+	}
+      break;
+    }
 
-  return unlink (path) >= 0;
+  return 0;
 }
 
-/*-------------------------------------------------------------------------.
-| Check if PATH already exists and make a backup of it right now.  Return  |
-| success (nonzero) only if the backup in either unneeded, or successful.  |
-| 									   |
-| For now, directories are considered to never need backup.  If ARCHIVE is |
-| nonzero, this is the archive and so, we do not have to backup block or   |
-| character devices, nor remote entities.				   |
-`-------------------------------------------------------------------------*/
-
-int
-maybe_backup_file (const char *path, int archive)
+/* Check if FILE_NAME already exists and make a backup of it right now.
+   Return success (nonzero) only if the backup is either unneeded, or
+   successful.  For now, directories are considered to never need
+   backup.  If THIS_IS_THE_ARCHIVE is nonzero, this is the archive and
+   so, we do not have to backup block or character devices, nor remote
+   entities.  */
+bool
+maybe_backup_file (const char *file_name, bool this_is_the_archive)
 {
   struct stat file_stat;
 
+  assign_string (&before_backup_name, file_name);
+
+  /* A run situation may exist between Emacs or other GNU programs trying to
+     make a backup for the same file simultaneously.  If theoretically
+     possible, real problems are unlikely.  Doing any better would require a
+     convention, GNU-wide, for all programs doing backups.  */
+
+  assign_string (&after_backup_name, 0);
+
   /* Check if we really need to backup the file.  */
 
-  if (archive && _remdev (path))
-    return 1;
+  if (this_is_the_archive && _remdev (file_name))
+    return true;
 
-  if (stat (path, &file_stat))
+  if (deref_stat (file_name, &file_stat) != 0)
     {
       if (errno == ENOENT)
-	return 1;
+	return true;
 
-      ERROR ((0, errno, "%s", path));
-      return 0;
+      stat_error (file_name);
+      return false;
     }
 
   if (S_ISDIR (file_stat.st_mode))
-    return 1;
+    return true;
 
-#ifdef S_ISBLK
-  if (archive && S_ISBLK (file_stat.st_mode))
-    return 1;
+  if (this_is_the_archive
+      && (S_ISBLK (file_stat.st_mode) || S_ISCHR (file_stat.st_mode)))
+    return true;
+
+  after_backup_name = find_backup_file_name (file_name, backup_type);
+  if (! after_backup_name)
+    xalloc_die ();
+
+  if (renameat (chdir_fd, before_backup_name, chdir_fd, after_backup_name)
+      == 0)
+    {
+      if (verbose_option)
+	fprintf (stdlis, _("Renaming %s to %s\n"),
+		 quote_n (0, before_backup_name),
+		 quote_n (1, after_backup_name));
+      return true;
+    }
+  else
+    {
+      /* The backup operation failed.  */
+      int e = errno;
+      ERROR ((0, e, _("%s: Cannot rename to %s"),
+	      quotearg_colon (before_backup_name),
+	      quote_n (1, after_backup_name)));
+      assign_string (&after_backup_name, 0);
+      return false;
+    }
+}
+
+/* Try to restore the recently backed up file to its original name.
+   This is usually only needed after a failed extraction.  */
+void
+undo_last_backup (void)
+{
+  if (after_backup_name)
+    {
+      if (renameat (chdir_fd, after_backup_name, chdir_fd, before_backup_name)
+	  != 0)
+	{
+	  int e = errno;
+	  ERROR ((0, e, _("%s: Cannot rename to %s"),
+		  quotearg_colon (after_backup_name),
+		  quote_n (1, before_backup_name)));
+	}
+      if (verbose_option)
+	fprintf (stdlis, _("Renaming %s back to %s\n"),
+		 quote_n (0, after_backup_name),
+		 quote_n (1, before_backup_name));
+      assign_string (&after_backup_name, 0);
+    }
+}
+
+/* Apply either stat or lstat to (NAME, BUF), depending on the
+   presence of the --dereference option.  NAME is relative to the
+   most-recent argument to chdir_do.  */
+int
+deref_stat (char const *name, struct stat *buf)
+{
+  return fstatat (chdir_fd, name, buf, fstatat_flags);
+}
+
+/* Read from FD into the buffer BUF with COUNT bytes.  Attempt to fill
+   BUF.  Wait until input is available; this matters because files are
+   opened O_NONBLOCK for security reasons, and on some file systems
+   this can cause read to fail with errno == EAGAIN.  Return the
+   actual number of bytes read, zero for EOF, or
+   SAFE_READ_ERROR upon error.  */
+size_t
+blocking_read (int fd, void *buf, size_t count)
+{
+  size_t bytes = safe_read (fd, buf, count);
+
+#if defined F_SETFL && O_NONBLOCK
+  if (bytes == SAFE_READ_ERROR && errno == EAGAIN)
+    {
+      int flags = fcntl (fd, F_GETFL);
+      if (0 <= flags && flags & O_NONBLOCK
+	  && fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
+	bytes = safe_read (fd, buf, count);
+    }
 #endif
 
-#ifdef S_ISCHR
-  if (archive && S_ISCHR (file_stat.st_mode))
-    return 1;
+  return bytes;
+}
+
+/* Write to FD from the buffer BUF with COUNT bytes.  Do a full write.
+   Wait until an output buffer is available; this matters because
+   files are opened O_NONBLOCK for security reasons, and on some file
+   systems this can cause write to fail with errno == EAGAIN.  Return
+   the actual number of bytes written, setting errno if that is less
+   than COUNT.  */
+size_t
+blocking_write (int fd, void const *buf, size_t count)
+{
+  size_t bytes = full_write (fd, buf, count);
+
+#if defined F_SETFL && O_NONBLOCK
+  if (bytes < count && errno == EAGAIN)
+    {
+      int flags = fcntl (fd, F_GETFL);
+      if (0 <= flags && flags & O_NONBLOCK
+	  && fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
+	{
+	  char const *buffer = buf;
+	  bytes += full_write (fd, buffer + bytes, count - bytes);
+	}
+    }
 #endif
 
-  assign_string (&before_backup_name, path);
+  return bytes;
+}
 
-  /* A run situation may exist between Emacs or other GNU programs trying to
-     make a backup for the same file simultaneously.  If theoretically
-     possible, real problems are unlikely.  Doing any better would require a
-     convention, GNU-wide, for all programs doing backups.  */
+/* Set FD's (i.e., assuming the working directory is PARENTFD, FILE's)
+   access time to ATIME.  */
+int
+set_file_atime (int fd, int parentfd, char const *file, struct timespec atime)
+{
+  struct timespec ts[2];
+  ts[0] = atime;
+  ts[1].tv_nsec = UTIME_OMIT;
+  return fdutimensat (fd, parentfd, file, ts, fstatat_flags);
+}
+
+/* A description of a working directory.  */
+struct wd
+{
+  /* The directory's name.  */
+  char const *name;
 
-  assign_string (&after_backup_name, NULL);
-  after_backup_name = find_backup_file_name (path);
-  if (after_backup_name == NULL)
-    FATAL_ERROR ((0, 0, "Virtual memory exhausted"));
+  /* If nonzero, the file descriptor of the directory, or AT_FDCWD if
+     the working directory.  If zero, the directory needs to be opened
+     to be used.  */
+  int fd;
+};
 
-  if (rename (before_backup_name, after_backup_name) == 0)
+/* A vector of chdir targets.  wd[0] is the initial working directory.  */
+static struct wd *wd;
+
+/* The number of working directories in the vector.  */
+static size_t wd_count;
+
+/* The allocated size of the vector.  */
+static size_t wd_alloc;
+
+/* The maximum number of chdir targets with open directories.
+   Don't make it too large, as many operating systems have a small
+   limit on the number of open file descriptors.  Also, the current
+   implementation does not scale well.  */
+enum { CHDIR_CACHE_SIZE = 16 };
+
+/* Indexes into WD of chdir targets with open file descriptors, sorted
+   most-recently used first.  Zero indexes are unused.  */
+static int wdcache[CHDIR_CACHE_SIZE];
+
+/* Number of nonzero entries in WDCACHE.  */
+static size_t wdcache_count;
+
+int
+chdir_count (void)
+{
+  if (wd_count == 0)
+    return wd_count;
+  return wd_count - 1;
+}
+
+/* DIR is the operand of a -C option; add it to vector of chdir targets,
+   and return the index of its location.  */
+int
+chdir_arg (char const *dir)
+{
+  if (wd_count == wd_alloc)
     {
-      if (verbose_option)
-	fprintf (stdlis, _("Renaming previous `%s' to `%s'\n"),
-		 before_backup_name, after_backup_name);
-      return 1;
+      if (wd_alloc == 0)
+	{
+	  wd_alloc = 2;
+	  wd = xmalloc (sizeof *wd * wd_alloc);
+	}
+      else
+	wd = x2nrealloc (wd, &wd_alloc, sizeof *wd);
+
+      if (! wd_count)
+	{
+	  wd[wd_count].name = ".";
+	  wd[wd_count].fd = AT_FDCWD;
+	  wd_count++;
+	}
     }
 
-  /* The backup operation failed.  */
+  /* Optimize the common special case of the working directory,
+     or the working directory as a prefix.  */
+  if (dir[0])
+    {
+      while (dir[0] == '.' && ISSLASH (dir[1]))
+	for (dir += 2;  ISSLASH (*dir);  dir++)
+	  continue;
+      if (! dir[dir[0] == '.'])
+	return wd_count - 1;
+    }
 
-  ERROR ((0, errno, _("%s: Cannot rename for backup"), before_backup_name));
-  assign_string (&after_backup_name, NULL);
-  return 0;
+  wd[wd_count].name = dir;
+  wd[wd_count].fd = 0;
+  return wd_count++;
 }
 
-/*-----------------------------------------------------------------------.
-| Try to restore the recently backed up file to its original name.  This |
-| is usually only needed after a failed extraction.			 |
-`-----------------------------------------------------------------------*/
+/* Index of current directory.  */
+int chdir_current;
+
+/* Value suitable for use as the first argument to openat, and in
+   similar locations for fstatat, etc.  This is an open file
+   descriptor, or AT_FDCWD if the working directory is current.  It is
+   valid until the next invocation of chdir_do.  */
+int chdir_fd = AT_FDCWD;
 
+/* Change to directory I, in a virtual way.  This does not actually
+   invoke chdir; it merely sets chdir_fd to an int suitable as the
+   first argument for openat, etc.  If I is 0, change to the initial
+   working directory; otherwise, I must be a value returned by
+   chdir_arg.  */
 void
-undo_last_backup (void)
+chdir_do (int i)
 {
-  if (after_backup_name)
+  if (chdir_current != i)
     {
-      if (rename (after_backup_name, before_backup_name) != 0)
-	ERROR ((0, errno, _("%s: Cannot rename from backup"),
-		before_backup_name));
-      if (verbose_option)
-	fprintf (stdlis, _("Renaming `%s' back to `%s'\n"),
-		 after_backup_name, before_backup_name);
-      assign_string (&after_backup_name, NULL);
+      struct wd *curr = &wd[i];
+      int fd = curr->fd;
+
+      if (! fd)
+	{
+	  if (! IS_ABSOLUTE_FILE_NAME (curr->name))
+	    chdir_do (i - 1);
+	  fd = openat (chdir_fd, curr->name,
+		       open_searchdir_flags & ~ O_NOFOLLOW);
+	  if (fd < 0)
+	    open_fatal (curr->name);
+
+	  curr->fd = fd;
+
+	  /* Add I to the cache, tossing out the lowest-ranking entry if the
+	     cache is full.  */
+	  if (wdcache_count < CHDIR_CACHE_SIZE)
+	    wdcache[wdcache_count++] = i;
+	  else
+	    {
+	      struct wd *stale = &wd[wdcache[CHDIR_CACHE_SIZE - 1]];
+	      if (close (stale->fd) != 0)
+		close_diag (stale->name);
+	      stale->fd = 0;
+	      wdcache[CHDIR_CACHE_SIZE - 1] = i;
+	    }
+	}
+
+      if (0 < fd)
+	{
+	  /* Move the i value to the front of the cache.  This is
+	     O(CHDIR_CACHE_SIZE), but the cache is small.  */
+	  size_t ci;
+	  int prev = wdcache[0];
+	  for (ci = 1; prev != i; ci++)
+	    {
+	      int cur = wdcache[ci];
+	      wdcache[ci] = prev;
+	      if (cur == i)
+		break;
+	      prev = cur;
+	    }
+	  wdcache[0] = i;
+	}
+
+      chdir_current = i;
+      chdir_fd = fd;
     }
 }
+
+char *
+tar_getcwd (void)
+{
+  static char *cwd;
+  namebuf_t nbuf;
+  int i;
+
+  if (!cwd)
+    cwd = xgetcwd ();
+  nbuf = namebuf_create (cwd);
+  for (i = 1; i <= chdir_current; i++)
+    namebuf_add_dir (nbuf, wd[i].name);
+  return namebuf_finish (nbuf);
+}
+
+void
+close_diag (char const *name)
+{
+  if (ignore_failed_read_option)
+    close_warn (name);
+  else
+    close_error (name);
+}
+
+void
+open_diag (char const *name)
+{
+  if (ignore_failed_read_option)
+    open_warn (name);
+  else
+    open_error (name);
+}
+
+void
+read_diag_details (char const *name, off_t offset, size_t size)
+{
+  if (ignore_failed_read_option)
+    read_warn_details (name, offset, size);
+  else
+    read_error_details (name, offset, size);
+}
+
+void
+readlink_diag (char const *name)
+{
+  if (ignore_failed_read_option)
+    readlink_warn (name);
+  else
+    readlink_error (name);
+}
+
+void
+savedir_diag (char const *name)
+{
+  if (ignore_failed_read_option)
+    savedir_warn (name);
+  else
+    savedir_error (name);
+}
+
+void
+seek_diag_details (char const *name, off_t offset)
+{
+  if (ignore_failed_read_option)
+    seek_warn_details (name, offset);
+  else
+    seek_error_details (name, offset);
+}
+
+void
+stat_diag (char const *name)
+{
+  if (ignore_failed_read_option)
+    stat_warn (name);
+  else
+    stat_error (name);
+}
+
+void
+file_removed_diag (const char *name, bool top_level,
+		   void (*diagfn) (char const *name))
+{
+  if (!top_level && errno == ENOENT)
+    {
+      WARNOPT (WARN_FILE_REMOVED,
+	       (0, 0, _("%s: File removed before we read it"),
+		quotearg_colon (name)));
+      set_exit_status (TAREXIT_DIFFERS);
+    }
+  else
+    diagfn (name);
+}
+
+void
+write_fatal_details (char const *name, ssize_t status, size_t size)
+{
+  write_error_details (name, status, size);
+  fatal_exit ();
+}
+
+/* Fork, aborting if unsuccessful.  */
+pid_t
+xfork (void)
+{
+  pid_t p = fork ();
+  if (p == (pid_t) -1)
+    call_arg_fatal ("fork", _("child process"));
+  return p;
+}
+
+/* Create a pipe, aborting if unsuccessful.  */
+void
+xpipe (int fd[2])
+{
+  if (pipe (fd) < 0)
+    call_arg_fatal ("pipe", _("interprocess channel"));
+}
+
+/* Return PTR, aligned upward to the next multiple of ALIGNMENT.
+   ALIGNMENT must be nonzero.  The caller must arrange for ((char *)
+   PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
+   locations.  */
+
+static inline void *
+ptr_align (void *ptr, size_t alignment)
+{
+  char *p0 = ptr;
+  char *p1 = p0 + alignment - 1;
+  return p1 - (size_t) p1 % alignment;
+}
+
+/* Return the address of a page-aligned buffer of at least SIZE bytes.
+   The caller should free *PTR when done with the buffer.  */
+
+void *
+page_aligned_alloc (void **ptr, size_t size)
+{
+  size_t alignment = getpagesize ();
+  size_t size1 = size + alignment;
+  if (size1 < size)
+    xalloc_die ();
+  *ptr = xmalloc (size1);
+  return ptr_align (*ptr, alignment);
+}
+
+
+
+struct namebuf
+{
+  char *buffer;		/* directory, '/', and directory member */
+  size_t buffer_size;	/* allocated size of name_buffer */
+  size_t dir_length;	/* length of directory part in buffer */
+};
+
+namebuf_t
+namebuf_create (const char *dir)
+{
+  namebuf_t buf = xmalloc (sizeof (*buf));
+  buf->buffer_size = strlen (dir) + 2;
+  buf->buffer = xmalloc (buf->buffer_size);
+  strcpy (buf->buffer, dir);
+  buf->dir_length = strlen (buf->buffer);
+  if (!ISSLASH (buf->buffer[buf->dir_length - 1]))
+    buf->buffer[buf->dir_length++] = DIRECTORY_SEPARATOR;
+  return buf;
+}
+
+void
+namebuf_free (namebuf_t buf)
+{
+  free (buf->buffer);
+  free (buf);
+}
+
+char *
+namebuf_name (namebuf_t buf, const char *name)
+{
+  size_t len = strlen (name);
+  while (buf->dir_length + len + 1 >= buf->buffer_size)
+    buf->buffer = x2realloc (buf->buffer, &buf->buffer_size);
+  strcpy (buf->buffer + buf->dir_length, name);
+  return buf->buffer;
+}
+
+void
+namebuf_add_dir (namebuf_t buf, const char *name)
+{
+  static char dirsep[] = { DIRECTORY_SEPARATOR, 0 };
+  if (!ISSLASH (buf->buffer[buf->dir_length - 1]))
+    {
+      namebuf_name (buf, dirsep);
+      buf->dir_length++;
+    }
+  namebuf_name (buf, name);
+  buf->dir_length += strlen (name);
+}
+
+char *
+namebuf_finish (namebuf_t buf)
+{
+  char *res = buf->buffer;
+  
+  if (ISSLASH (buf->buffer[buf->dir_length - 1]))
+    buf->buffer[buf->dir_length] = 0;
+  free (buf);
+  return res;
+}
+
+/* Return the filenames in directory NAME, relative to the chdir_fd.
+   If the directory does not exist, report error if MUST_EXIST is
+   true.
+
+   Return NULL on errors.
+*/
+char *
+tar_savedir (const char *name, int must_exist)
+{
+  char *ret = NULL;
+  DIR *dir = NULL;
+  int fd = openat (chdir_fd, name, open_read_flags | O_DIRECTORY);
+  if (fd < 0)
+    {
+      if (!must_exist && errno == ENOENT)
+	return NULL;
+      open_error (name);
+    }
+  else if (! ((dir = fdopendir (fd))
+	      && (ret = streamsavedir (dir))))
+    savedir_error (name);
+
+  if (dir ? closedir (dir) != 0 : 0 <= fd && close (fd) != 0)
+    savedir_error (name);
+
+  return ret;
+}