/* Miscellaneous functions, not really specific to GNU tar.
- Copyright (C) 1988, 92, 94, 95, 96, 97 Free Software Foundation, Inc.
+
+ Copyright (C) 1988, 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
+ 2003, 2004, 2005, 2006, 2007, 2009, 2010 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
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. */
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
-#include "system.h"
+#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"
\f
/* 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;
+ *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)
*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)
{
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)
source++;
break;
- case 'n':
- *destination++ = '\n';
+ case 'a':
+ *destination++ = '\a';
source++;
break;
- case 't':
- *destination++ = '\t';
+ case 'b':
+ *destination++ = '\b';
source++;
break;
source++;
break;
- case 'b':
- *destination++ = '\b';
+ case 'n':
+ *destination++ = '\n';
source++;
break;
source++;
break;
+ case 't':
+ *destination++ = '\t';
+ source++;
+ break;
+
+ case 'v':
+ *destination++ = '\v';
+ source++;
+ break;
+
case '?':
*destination++ = 0177;
source++;
*destination = '\0';
return result;
}
-\f
-/* 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 = xgetcwd ();
+ 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)
+\f
+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;
+\f
+/* Handling numbers. */
+
+/* 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
- *merge_point = second_list;
+ {
+ int i = 9;
+ *p++ = '.';
- return result;
+ while (ns % 10 == 0)
+ {
+ ns /= 10;
+ i--;
+ }
-#undef SUCCESSOR
+ 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;
}
\f
/* 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;
-/*------------------------------------------------------------------------.
-| Returns nonzero if p is `.' or `..'. This could be a macro for speed. |
-`------------------------------------------------------------------------*/
+/* 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);
-/* 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. */
+ 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++;
+ }
-int
-is_dot_or_dotdot (const char *p)
-{
- return (p[0] == '\0'
- || (p[0] == '.' && (p[1] == '\0'
- || (p[1] == '.' && p[2] == '\0'))));
+ return ! file_name[0] || (file_name[0] == '.' && ! file_name[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). |
-`-------------------------------------------------------------------------*/
+/* 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)
+{
+ if (must_be_dot_or_slash (file_name))
+ {
+ errno = 0;
+ return -1;
+ }
+
+ 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;
- if (S_ISDIR (stat_buffer.st_mode))
- if (recurse)
- {
- DIR *dirp = opendir (path);
- struct dirent *dp;
+ /* 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 (dirp == NULL)
- return 0;
+ if (safer_rmdir (file_name) == 0)
+ return 1;
- while (dp = readdir (dirp), dp && !is_dot_or_dotdot (dp->d_name))
+ 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;
+
+ case WANT_DIRECTORY_REMOVE_OPTION:
+ return -1;
+
+ case RECURSIVE_REMOVE_OPTION:
{
- char *path_buffer = new_name (path, dp->d_name);
+ char *directory = savedir (file_name);
+ 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 (fstatat (chdir_fd, 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;
-#endif
+ if (this_is_the_archive
+ && (S_ISBLK (file_stat.st_mode) || S_ISCHR (file_stat.st_mode)))
+ return true;
-#ifdef S_ISCHR
- if (archive && S_ISCHR (file_stat.st_mode))
- return 1;
-#endif
+ 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;
+ }
+}
- assign_string (&before_backup_name, path);
+/* 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);
+ }
+}
- /* 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. */
+/* Depending on DEREF, apply either stat or lstat to (NAME, BUF). */
+int
+deref_stat (bool deref, char const *name, struct stat *buf)
+{
+ return fstatat (chdir_fd, name, buf, deref ? 0 : AT_SYMLINK_NOFOLLOW);
+}
- 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"));
+/* Set FD's (i.e., assuming the working directory is PARENTFD, FILE's)
+ access time to ATIME. ATFLAG controls symbolic-link following, in
+ the style of openat. */
+int
+set_file_atime (int fd, int parentfd, char const *file, struct timespec atime,
+ int atflag)
+{
+ struct timespec ts[2];
+ ts[0] = atime;
+ ts[1].tv_nsec = UTIME_OMIT;
+ return fdutimensat (fd, parentfd, file, ts, atflag);
+}
+
+/* A description of a working directory. */
+struct wd
+{
+ /* The directory's name. */
+ char const *name;
+
+ /* 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;
+};
+
+/* 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;
- if (rename (before_backup_name, after_backup_name) == 0)
+/* 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 ()
+{
+ 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);
+ static size_t counter;
+ 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);
+ 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 curr = wdcache[ci];
+ wdcache[ci] = prev;
+ if (curr == i)
+ break;
+ prev = curr;
+ }
+ wdcache[0] = i;
+ }
+
+ chdir_current = i;
+ chdir_fd = fd;
+ }
+}
+\f
+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
+dir_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: Directory 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);
+}
+
+\f
+
+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;
}
projects / chaz / tar / blobdiff