/*
* Backup handling code.
*
* Copyright (C) 1999 Andrew Tridgell
* Copyright (C) 2003-2020 Wayne Davison
*
* 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 3 of the License, 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, visit the http://fsf.org website.
*/
#include "rsync.h"
#include "ifuncs.h"
extern int am_root;
extern int preserve_acls;
extern int preserve_xattrs;
extern int preserve_devices;
extern int preserve_specials;
extern int preserve_links;
extern int safe_symlinks;
extern int backup_dir_len;
extern int backup_dir_dels_len;
extern unsigned int backup_dir_remainder;
extern unsigned int backup_dir_dels_remainder;
extern char backup_dir_buf[MAXPATHLEN];
extern char backup_dir_dels_buf[MAXPATHLEN];
extern char *backup_suffix;
extern char *backup_suffix_dels;
extern char *backup_dir;
extern char *backup_dir_dels;
static BOOL deleting;
/* Returns -1 on error, 0 on missing dir, and 1 on present dir. */
static int validate_backup_dir(char *buf)
{
STRUCT_STAT st;
if (do_lstat(buf, &st) < 0) {
if (errno == ENOENT)
return 0;
rsyserr(FERROR, errno, "backup lstat %s failed", buf);
return -1;
}
if (!S_ISDIR(st.st_mode)) {
int flags = get_del_for_flag(st.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
if (delete_item(buf, st.st_mode, flags) == 0)
return 0;
return -1;
}
return 1;
}
/* Create a backup path from the given fname, putting the result into
* backup_dir_buf. Any new directories (compared to the prior backup
* path) are ensured to exist as directories, replacing anything else
* that may be in the way (e.g. a symlink). */
static BOOL copy_valid_path(const char *fname, char *buf, int prefix_len, unsigned int remainder, const char *suffix)
{
const char *f;
int val;
BOOL ret = True;
stat_x sx;
char *b, *rel = buf + prefix_len, *name = rel;
for (f = fname, b = rel; *f && *f == *b; f++, b++) {
if (*b == '/')
name = b + 1;
}
if (stringjoin(rel, remainder, fname, suffix, NULL) >= remainder) {
rprintf(FERROR, "backup filename too long\n");
*name = '\0';
return False;
}
for ( ; ; name = b + 1) {
if ((b = strchr(name, '/')) == NULL)
return True;
*b = '\0';
val = validate_backup_dir(buf);
if (val == 0)
break;
if (val < 0) {
*name = '\0';
return False;
}
*b = '/';
}
init_stat_x(&sx);
for ( ; b; name = b + 1, b = strchr(name, '/')) {
*b = '\0';
while (do_mkdir(buf, ACCESSPERMS) < 0) {
if (errno == EEXIST) {
val = validate_backup_dir(buf);
if (val > 0)
break;
if (val == 0)
continue;
} else
rsyserr(FERROR, errno, "backup mkdir %s failed", backup_dir_buf);
*name = '\0';
ret = False;
goto cleanup;
}
/* Try to transfer the directory settings of the actual dir
* that the files are coming from. */
if (x_stat(rel, &sx.st, NULL) < 0)
rsyserr(FERROR, errno, "backup stat %s failed", full_fname(rel));
else {
struct file_struct *file;
if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
continue;
#ifdef SUPPORT_ACLS
if (preserve_acls && !S_ISLNK(file->mode)) {
get_acl(rel, &sx);
cache_tmp_acl(file, &sx);
free_acl(&sx);
}
#endif
#ifdef SUPPORT_XATTRS
if (preserve_xattrs) {
get_xattr(rel, &sx);
cache_tmp_xattr(file, &sx);
free_xattr(&sx);
}
#endif
set_file_attrs(buf, file, NULL, NULL, 0);
unmake_file(file);
}
*b = '/';
}
cleanup:
#ifdef SUPPORT_ACLS
uncache_tmp_acls();
#endif
#ifdef SUPPORT_XATTRS
uncache_tmp_xattrs();
#endif
return ret;
}
/* Make a complete pathname for backup file and verify any new path elements. */
char *get_backup_name(const char *fname)
{
char *buf = deleting ? backup_dir_dels_buf : backup_dir_buf;
char *suffix = deleting ? backup_suffix_dels : backup_suffix;
if (backup_dir) {
int prefix_len = deleting ? backup_dir_dels_len : backup_dir_len;
unsigned int remainder = deleting ? backup_dir_dels_remainder : backup_dir_remainder;
static int initialized = 0;
if (!initialized) {
int ret;
if (backup_dir_len > 1)
backup_dir_buf[backup_dir_len-1] = '\0';
ret = make_path(backup_dir_buf, ACCESSPERMS, 0);
if (backup_dir_len > 1)
backup_dir_buf[backup_dir_len-1] = '/';
if (ret < 0)
return NULL;
initialized = 1;
}
/* copy fname into backup_dir_buf while validating the dirs. */
if (copy_valid_path(fname, buf, prefix_len, remainder, suffix))
return buf;
/* copy_valid_path() has printed an error message. */
return NULL;
}
if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, suffix, NULL) < MAXPATHLEN)
return buf;
rprintf(FERROR, "backup filename too long\n");
return NULL;
}
/* Has same return codes as make_backup(). */
static inline int link_or_rename(const char *from, const char *to,
BOOL prefer_rename, STRUCT_STAT *stp)
{
#ifdef SUPPORT_HARD_LINKS
if (!prefer_rename) {
#ifndef CAN_HARDLINK_SYMLINK
if (S_ISLNK(stp->st_mode))
return 0; /* Use copy code. */
#endif
#ifndef CAN_HARDLINK_SPECIAL
if (IS_SPECIAL(stp->st_mode) || IS_DEVICE(stp->st_mode))
return 0; /* Use copy code. */
#endif
if (do_link(from, to) == 0) {
if (DEBUG_GTE(BACKUP, 1))
rprintf(FINFO, "make_backup: HLINK %s successful.\n", from);
return 2;
}
/* We prefer to rename a regular file rather than copy it. */
if (!S_ISREG(stp->st_mode) || errno == EEXIST || errno == EISDIR)
return 0;
}
#endif
if (do_rename(from, to) == 0) {
if (stp->st_nlink > 1 && !S_ISDIR(stp->st_mode)) {
/* If someone has hard-linked the file into the backup
* dir, rename() might return success but do nothing! */
robust_unlink(from); /* Just in case... */
}
if (DEBUG_GTE(BACKUP, 1))
rprintf(FINFO, "make_backup: RENAME %s successful.\n", from);
return 1;
}
return 0;
}
/* Hard-link, rename, or copy an item to the backup name. Returns 0 for
* failure, 1 if item was moved, 2 if item was duplicated or hard linked
* into backup area, or 3 if item doesn't exist or isn't a regular file. */
int make_backup(const char *fname, BOOL prefer_rename)
{
stat_x sx;
struct file_struct *file;
int save_preserve_xattrs;
char *buf;
int ret = 0;
init_stat_x(&sx);
/* Return success if no file to keep. */
if (x_lstat(fname, &sx.st, NULL) < 0)
return 3;
if (!(buf = get_backup_name(fname)))
return 0;
/* Try a hard-link or a rename first. Using rename is not atomic, but
* is more efficient than forcing a copy for larger files when no hard-
* linking is possible. */
if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
goto success;
if (errno == EEXIST || errno == EISDIR) {
STRUCT_STAT bakst;
if (do_lstat(buf, &bakst) == 0) {
int flags = get_del_for_flag(bakst.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
if (delete_item(buf, bakst.st_mode, flags) != 0)
return 0;
}
if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
goto success;
}
/* Fall back to making a copy. */
if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS)))
return 3; /* the file could have disappeared */
#ifdef SUPPORT_ACLS
if (preserve_acls && !S_ISLNK(file->mode)) {
get_acl(fname, &sx);
cache_tmp_acl(file, &sx);
free_acl(&sx);
}
#endif
#ifdef SUPPORT_XATTRS
if (preserve_xattrs) {
get_xattr(fname, &sx);
cache_tmp_xattr(file, &sx);
free_xattr(&sx);
}
#endif
/* Check to see if this is a device file, or link */
if ((am_root && preserve_devices && IS_DEVICE(file->mode))
|| (preserve_specials && IS_SPECIAL(file->mode))) {
if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
rsyserr(FERROR, errno, "mknod %s failed", full_fname(buf));
else if (DEBUG_GTE(BACKUP, 1))
rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname);
ret = 2;
}
#ifdef SUPPORT_LINKS
if (!ret && preserve_links && S_ISLNK(file->mode)) {
const char *sl = F_SYMLINK(file);
if (safe_symlinks && unsafe_symlink(sl, fname)) {
if (INFO_GTE(SYMSAFE, 1)) {
rprintf(FINFO, "not backing up unsafe symlink \"%s\" -> \"%s\"\n",
fname, sl);
}
ret = 2;
} else {
if (do_symlink(sl, buf) < 0)
rsyserr(FERROR, errno, "link %s -> \"%s\"", full_fname(buf), sl);
else if (DEBUG_GTE(BACKUP, 1))
rprintf(FINFO, "make_backup: SYMLINK %s successful.\n", fname);
ret = 2;
}
}
#endif
if (!ret && !S_ISREG(file->mode)) {
rprintf(FINFO, "make_bak: skipping non-regular file %s\n", fname);
unmake_file(file);
#ifdef SUPPORT_ACLS
uncache_tmp_acls();
#endif
#ifdef SUPPORT_XATTRS
uncache_tmp_xattrs();
#endif
return 3;
}
/* Copy to backup tree if a file. */
if (!ret) {
if (copy_file(fname, buf, -1, file->mode) < 0) {
rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
full_fname(fname), buf);
unmake_file(file);
#ifdef SUPPORT_ACLS
uncache_tmp_acls();
#endif
#ifdef SUPPORT_XATTRS
uncache_tmp_xattrs();
#endif
return 0;
}
if (DEBUG_GTE(BACKUP, 1))
rprintf(FINFO, "make_backup: COPY %s successful.\n", fname);
ret = 2;
}
save_preserve_xattrs = preserve_xattrs;
preserve_xattrs = 0;
set_file_attrs(buf, file, NULL, fname, ATTRS_ACCURATE_TIME);
preserve_xattrs = save_preserve_xattrs;
unmake_file(file);
#ifdef SUPPORT_ACLS
uncache_tmp_acls();
#endif
#ifdef SUPPORT_XATTRS
uncache_tmp_xattrs();
#endif
success:
if (INFO_GTE(BACKUP, 1))
rprintf(FINFO, "backed up %s to %s\n", fname, buf);
return ret;
}
/* backup switch routine called only when backing-up removed file */
int safe_delete(const char *fname)
{
int ret;
deleting = 1;
ret = make_backup(fname, True);
deleting = 0;
return ret;
}
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