Avoid leaving a file open on error return.
[rsync.git] / backup.c
index 54d5fae87abe4a2e8f256fe22d2ac446cce898ca..5f40b39af9592ef5017d341cf953cde93565fc2c 100644 (file)
--- a/backup.c
+++ b/backup.c
-/* 
-   Copyright (C) Andrew Tridgell 1999
-   
-   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 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, write to the Free Software
-   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
-
-/* backup handling code */
+/*
+ * Backup handling code.
+ *
+ * Copyright (C) 1999 Andrew Tridgell
+ * Copyright (C) 2003-2018 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 verbose;
+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 unsigned int backup_dir_remainder;
+extern char backup_dir_buf[MAXPATHLEN];
 extern char *backup_suffix;
+extern char *backup_dir;
 
+/* Returns -1 on error, 0 on missing dir, and 1 on present dir. */
+static int validate_backup_dir(void)
+{
+       STRUCT_STAT st;
 
-int make_backup(char *fname)
+       if (do_lstat(backup_dir_buf, &st) < 0) {
+               if (errno == ENOENT)
+                       return 0;
+               rsyserr(FERROR, errno, "backup lstat %s failed", backup_dir_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(backup_dir_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 fnamebak[MAXPATHLEN];
-       if (strlen(fname) + strlen(backup_suffix) > (MAXPATHLEN-1)) {
-               rprintf(FERROR,"backup filename too long\n");
+       const char *f;
+       int val;
+       BOOL ret = True;
+       stat_x sx;
+       char *b, *rel = backup_dir_buf + backup_dir_len, *name = rel;
+
+       for (f = fname, b = rel; *f && *f == *b; f++, b++) {
+               if (*b == '/')
+                       name = b + 1;
+       }
+
+       if (stringjoin(rel, backup_dir_remainder, fname, backup_suffix, NULL) >= backup_dir_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();
+               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(backup_dir_buf, ACCESSPERMS) < 0) {
+                       if (errno == EEXIST) {
+                               val = validate_backup_dir();
+                               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(backup_dir_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)
+{
+       if (backup_dir) {
+               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, 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))
+                       return backup_dir_buf;
+               /* copy_valid_path() has printed an error message. */
+               return NULL;
+       }
+
+       if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN)
+               return backup_dir_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;
        }
 
-       slprintf(fnamebak,sizeof(fnamebak),"%s%s",fname,backup_suffix);
-       if (do_rename(fname,fnamebak) != 0) {
-               /* cygwin (at least version b19) reports EINVAL */
-               if (errno != ENOENT && errno != EINVAL) {
-                       rprintf(FERROR,"rename %s %s : %s\n",fname,fnamebak,strerror(errno));
+       /* 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;
                }
-       } else if (verbose > 1) {
-               rprintf(FINFO,"backed up %s to %s\n",fname,fnamebak);
+               if (DEBUG_GTE(BACKUP, 1))
+                       rprintf(FINFO, "make_backup: COPY %s successful.\n", fname);
+               ret = 2;
        }
-       return 1;
+
+       save_preserve_xattrs = preserve_xattrs;
+       preserve_xattrs = 0;
+       set_file_attrs(buf, file, NULL, fname, ATTRS_SET_NANO);
+       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;
 }