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+/* Miscellaneous functions, not really specific to GNU tar.
+
+ Copyright (C) 1988, 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
+ 2003, 2004, 2005, 2006, 2007 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
+ version.
+
+ This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#include <system.h>
+#include <rmt.h>
+#include "common.h"
+#include <quotearg.h>
+#include <save-cwd.h>
+#include <xgetcwd.h>
+#include <unlinkdir.h>
+#include <utimens.h>
+
+#if HAVE_STROPTS_H
+# include <stropts.h>
+#endif
+#if HAVE_SYS_FILIO_H
+# include <sys/filio.h>
+#endif
+
+
+/* Handling strings. */
+
+/* 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) : 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 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. */
+char *
+quote_copy_string (const char *string)
+{
+ const char *source = string;
+ char *destination = 0;
+ char *buffer = 0;
+ int copying = 0;
+
+ while (*source)
+ {
+ int character = *source++;
+
+ switch (character)
+ {
+ case '\n': case '\\':
+ if (!copying)
+ {
+ size_t length = (source - string) - 1;
+
+ copying = 1;
+ buffer = xmalloc (length + 2 + 2 * strlen (source) + 1);
+ memcpy (buffer, string, length);
+ destination = buffer + length;
+ }
+ *destination++ = '\\';
+ *destination++ = character == '\\' ? '\\' : 'n';
+ break;
+
+ default:
+ if (copying)
+ *destination++ = character;
+ break;
+ }
+ }
+ if (copying)
+ {
+ *destination = '\0';
+ return buffer;
+ }
+ return 0;
+}
+
+/* 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)
+{
+ int result = 1;
+ 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)
+ {
+ case '\\':
+ *destination++ = '\\';
+ source++;
+ break;
+
+ case 'a':
+ *destination++ = '\a';
+ source++;
+ break;
+
+ case 'b':
+ *destination++ = '\b';
+ source++;
+ break;
+
+ case 'f':
+ *destination++ = '\f';
+ source++;
+ break;
+
+ case 'n':
+ *destination++ = '\n';
+ source++;
+ break;
+
+ case 'r':
+ *destination++ = '\r';
+ source++;
+ break;
+
+ case 't':
+ *destination++ = '\t';
+ source++;
+ break;
+
+ case 'v':
+ *destination++ = '\v';
+ source++;
+ break;
+
+ case '?':
+ *destination++ = 0177;
+ source++;
+ break;
+
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ {
+ int value = *source++ - '0';
+
+ if (*source < '0' || *source > '7')
+ {
+ *destination++ = value;
+ break;
+ }
+ value = value * 8 + *source++ - '0';
+ if (*source < '0' || *source > '7')
+ {
+ *destination++ = value;
+ break;
+ }
+ value = value * 8 + *source++ - '0';
+ *destination++ = value;
+ break;
+ }
+
+ default:
+ result = 0;
+ *destination++ = '\\';
+ if (*source)
+ *destination++ = *source++;
+ break;
+ }
+ else if (source != destination)
+ *destination++ = *source++;
+ else
+ source++, destination++;
+
+ if (source != destination)
+ *destination = '\0';
+ return result;
+}
+
+/* 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
+ {
+ 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;
+
+ 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;
+}
+
+/* File handling. */
+
+/* Saved names in case backup needs to be undone. */
+static char *before_backup_name;
+static char *after_backup_name;
+
+/* Return 1 if FILE_NAME is obviously "." or "/". */
+static bool
+must_be_dot_or_slash (char const *file_name)
+{
+ file_name += FILE_SYSTEM_PREFIX_LEN (file_name);
+
+ 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++;
+ }
+
+ return ! file_name[0] || (file_name[0] == '.' && ! file_name[1]);
+ }
+}
+
+/* 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 rmdir (file_name);
+}
+
+/* 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 *file_name, enum remove_option option)
+{
+ /* 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 (try_unlink_first)
+ {
+ if (unlink (file_name) == 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;
+
+ switch (errno)
+ {
+ case ENOTDIR:
+ return !try_unlink_first && unlink (file_name) == 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 *directory = savedir (file_name);
+ char const *entry;
+ size_t entrylen;
+
+ if (! directory)
+ 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 (directory);
+ return safer_rmdir (file_name) == 0;
+ }
+ }
+ break;
+ }
+
+ return 0;
+}
+
+/* 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;
+
+ /* Check if we really need to backup the file. */
+
+ if (this_is_the_archive && _remdev (file_name))
+ return true;
+
+ if (stat (file_name, &file_stat))
+ {
+ if (errno == ENOENT)
+ return true;
+
+ stat_error (file_name);
+ return false;
+ }
+
+ if (S_ISDIR (file_stat.st_mode))
+ return true;
+
+ if (this_is_the_archive
+ && (S_ISBLK (file_stat.st_mode) || S_ISCHR (file_stat.st_mode)))
+ return true;
+
+ 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);
+ after_backup_name = find_backup_file_name (file_name, backup_type);
+ if (! after_backup_name)
+ xalloc_die ();
+
+ if (rename (before_backup_name, 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 (rename (after_backup_name, 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);
+ }
+}
+
+/* Depending on DEREF, apply either stat or lstat to (NAME, BUF). */
+int
+deref_stat (bool deref, char const *name, struct stat *buf)
+{
+ return deref ? stat (name, buf) : lstat (name, buf);
+}
+
+/* Set FD's (i.e., FILE's) access time to TIMESPEC[0]. If that's not
+ possible to do by itself, set its access and data modification
+ times to TIMESPEC[0] and TIMESPEC[1], respectively. */
+int
+set_file_atime (int fd, char const *file, struct timespec const timespec[2])
+{
+#ifdef _FIOSATIME
+ if (0 <= fd)
+ {
+ struct timeval timeval;
+ timeval.tv_sec = timespec[0].tv_sec;
+ timeval.tv_usec = timespec[0].tv_nsec / 1000;
+ if (ioctl (fd, _FIOSATIME, &timeval) == 0)
+ return 0;
+ }
+#endif
+
+ return gl_futimens (fd, file, timespec);
+}
+
+/* A description of a working directory. */
+struct wd
+{
+ char const *name;
+ int saved;
+ struct saved_cwd saved_cwd;
+};
+
+/* 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 wds;
+
+/* The allocated size of the vector. */
+static size_t wd_alloc;
+
+/* 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 (wds == wd_alloc)
+ {
+ if (wd_alloc == 0)
+ {
+ wd_alloc = 2;
+ wd = xmalloc (sizeof *wd * wd_alloc);
+ }
+ else
+ wd = x2nrealloc (wd, &wd_alloc, sizeof *wd);
+
+ if (! wds)
+ {
+ wd[wds].name = ".";
+ wd[wds].saved = 0;
+ wds++;
+ }
+ }
+
+ /* 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 wds - 1;
+ }
+
+ wd[wds].name = dir;
+ wd[wds].saved = 0;
+ return wds++;
+}
+
+/* Change to directory I. If I is 0, change to the initial working
+ directory; otherwise, I must be a value returned by chdir_arg. */
+void
+chdir_do (int i)
+{
+ static int previous;
+
+ if (previous != i)
+ {
+ struct wd *prev = &wd[previous];
+ struct wd *curr = &wd[i];
+
+ if (! prev->saved)
+ {
+ int err = 0;
+ prev->saved = 1;
+ if (save_cwd (&prev->saved_cwd) != 0)
+ err = errno;
+ else if (0 <= prev->saved_cwd.desc)
+ {
+ /* Make sure we still have at least one descriptor available. */
+ int fd1 = prev->saved_cwd.desc;
+ int fd2 = dup (fd1);
+ if (0 <= fd2)
+ close (fd2);
+ else if (errno == EMFILE)
+ {
+ /* Force restore_cwd to use chdir_long. */
+ close (fd1);
+ prev->saved_cwd.desc = -1;
+ prev->saved_cwd.name = xgetcwd ();
+ }
+ else
+ err = errno;
+ }
+
+ if (err)
+ FATAL_ERROR ((0, err, _("Cannot save working directory")));
+ }
+
+ if (curr->saved)
+ {
+ if (restore_cwd (&curr->saved_cwd))
+ FATAL_ERROR ((0, 0, _("Cannot change working directory")));
+ }
+ else
+ {
+ if (i && ! ISSLASH (curr->name[0]))
+ chdir_do (i - 1);
+ if (chdir (curr->name) != 0)
+ chdir_fatal (curr->name);
+ }
+
+ previous = i;
+ }
+}
+
+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
+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);
+}
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