Move var declaration for older C compilers.
[rsync.git] / backup.c
index 00e3e96d9b828f7b90e68b9c381c7c04daa31572..e535e6f5af05e4b256f95186a42912349e72da45 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) 2003-2009 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 backup_suffix_len;
+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;
 
-extern int am_root;
-extern int preserve_devices;
-extern int preserve_links;
-extern int preserve_hard_links;
-extern int orig_umask;
-extern int safe_symlinks;
-
-/* make a complete pathname for backup file */
-char *get_backup_name(char *fname)
+/* Returns -1 on error, 0 on missing dir, and 1 on present dir. */
+static int validate_backup_dir(void)
 {
-       if (backup_dir) {
-               if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
-                              fname, backup_suffix, NULL) < backup_dir_remainder)
-                       return backup_dir_buf;
-       } else {
-               if (stringjoin(backup_dir_buf, MAXPATHLEN,
-                              fname, backup_suffix, NULL) < MAXPATHLEN)
-                       return backup_dir_buf;
-       }
+       STRUCT_STAT st;
 
-       rprintf(FERROR, "backup filename too long\n");
-       return NULL;
+       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;
 }
 
-/* simple backup creates a backup with a suffix in the same directory */
-static int make_simple_backup(char *fname)
+/* 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)
 {
-       int rename_errno;
-       char *fnamebak = get_backup_name(fname);
+       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 (!fnamebak)
-               return 0;
+       if (stringjoin(rel, backup_dir_remainder, fname, backup_suffix, NULL) >= backup_dir_remainder) {
+               rprintf(FERROR, "backup filename too long\n");
+               *name = '\0';
+               return False;
+       }
 
-       while (1) {
-               if (do_rename(fname, fnamebak) == 0) {
-                       if (verbose > 1) {
-                               rprintf(FINFO, "backed up %s to %s\n",
-                                       safe_fname(fname),
-                                       safe_fname(fnamebak));
-                       }
+       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;
                }
-               /* cygwin (at least version b19) reports EINVAL */
-               if (errno == ENOENT || errno == EINVAL)
-                       break;
 
-               rename_errno = errno;
-               if (errno == EISDIR && do_rmdir(fnamebak) == 0)
-                       continue;
-               if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
-                       continue;
-
-               rsyserr(FERROR, rename_errno, "rename %s to backup %s",
-                       safe_fname(fname), safe_fname(fnamebak));
-               errno = rename_errno;
-               return 0;
+               *b = '/';
        }
 
-       return 1;
-}
-
-
-/****************************************************************************
-Create a directory given an absolute path, perms based upon another directory
-path
-****************************************************************************/
-static int make_bak_dir(char *fullpath)
-{
-       STRUCT_STAT st;
-       char *rel = fullpath + backup_dir_len;
-       char *end = rel + strlen(rel);
-       char *p = end;
-
-       while (strncmp(fullpath, "./", 2) == 0)
-               fullpath += 2;
-
-       /* Try to find an existing dir, starting from the deepest dir. */
-       while (1) {
-               if (--p == fullpath) {
-                       p += strlen(p);
-                       goto failure;
-               }
-               if (*p == '/') {
-                       *p = '\0';
-                       if (do_mkdir(fullpath, 0777 & ~orig_umask) == 0)
-                               break;
-                       if (errno != ENOENT) {
-                               rsyserr(FERROR, errno,
-                                       "make_bak_dir mkdir %s failed",
-                                       full_fname(fullpath));
-                               goto failure;
-                       }
+       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;
                }
-       }
 
-       /* Make all the dirs that we didn't find on the way here. */
-       while (1) {
-               if (p >= rel) {
-                       /* Try to transfer the directory settings of the
-                        * actual dir that the files are coming from. */
-                       if (do_stat(rel, &st) < 0) {
-                               rsyserr(FERROR, errno,
-                                       "make_bak_dir stat %s failed",
-                                       full_fname(rel));
-                       } else {
-                               do_lchown(fullpath, st.st_uid, st.st_gid);
-                               do_chmod(fullpath, st.st_mode);
+               /* 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);
                }
-               *p = '/';
-               p += strlen(p);
-               if (p == end)
-                       break;
-               if (do_mkdir(fullpath, 0777 & ~orig_umask) < 0) {
-                       rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
-                               full_fname(fullpath));
-                       goto failure;
-               }
+
+               *b = '/';
        }
-       return 0;
 
-failure:
-       while (p != end) {
-               *p = '/';
-               p += strlen(p);
+  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) {
+               /* 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;
        }
-       return -1;
+
+       if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN)
+               return backup_dir_buf;
+
+       rprintf(FERROR, "backup filename too long\n");
+       return NULL;
 }
 
-/* robustly move a file, creating new directory structures if necessary */
-static int robust_move(char *src, char *dst)
+/* 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)
 {
-       if (robust_rename(src, dst, 0755) < 0 && (errno != ENOENT
-           || make_bak_dir(dst) < 0 || robust_rename(src, dst, 0755) < 0))
-               return -1;
+#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;
 }
 
-
-/* If we have a --backup-dir, then we get here from make_backup().
- * We will move the file to be deleted into a parallel directory tree. */
-static int keep_backup(char *fname)
+/* Hard-link, rename, or copy an item to the backup name.  Returns 2 if item
+ * was duplicated into backup area, 1 if item was moved, or 0 for failure.*/
+int make_backup(const char *fname, BOOL prefer_rename)
 {
-       STRUCT_STAT st;
+       stat_x sx;
        struct file_struct *file;
-       char *buf;
-       int kept = 0;
-       int ret_code;
-
-       /* return if no file to keep */
-       if (do_lstat(fname, &st) < 0)
-               return 1;
+       int save_preserve_xattrs;
+       char *buf = get_backup_name(fname);
+       int ret = 0;
 
-       if (!(file = make_file(fname, NULL, NO_FILTERS)))
-               return 1; /* the file could have disappeared */
-
-       if (!(buf = get_backup_name(fname)))
+       if (!buf)
                return 0;
 
-       /* Check to see if this is a device file, or link */
-       if (IS_DEVICE(file->mode)) {
-               if (am_root && preserve_devices) {
-                       if (do_mknod(buf, file->mode, file->u.rdev) < 0
-                           && (errno != ENOENT || make_bak_dir(buf) < 0
-                            || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
-                               rsyserr(FERROR, errno, "mknod %s failed",
-                                       full_fname(buf));
-                       } else if (verbose > 2) {
-                               rprintf(FINFO,
-                                       "make_backup: DEVICE %s successful.\n",
-                                       safe_fname(fname));
-                       }
+       init_stat_x(&sx);
+       /* Return success if no file to keep. */
+       if (x_lstat(fname, &sx.st, NULL) < 0)
+               return 1;
+
+       /* 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;
                }
-               kept = 1;
-               do_unlink(fname);
+               if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
+                       goto success;
        }
 
-       if (!kept && S_ISDIR(file->mode)) {
-               /* make an empty directory */
-               if (do_mkdir(buf, file->mode) < 0
-                   && (errno != ENOENT || make_bak_dir(buf) < 0
-                    || do_mkdir(buf, file->mode) < 0)) {
-                       rsyserr(FINFO, errno, "mkdir %s failed",
-                               full_fname(buf));
-               }
+       /* Fall back to making a copy. */
+       if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS)))
+               return 1; /* the file could have disappeared */
 
-               ret_code = do_rmdir(fname);
-               if (verbose > 2) {
-                       rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
-                               full_fname(fname), ret_code);
-               }
-               kept = 1;
+#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 (!kept && preserve_links && S_ISLNK(file->mode)) {
-               if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
-                       if (verbose) {
-                               rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
-                                       full_fname(buf), file->u.link);
+       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);
                        }
-                       kept = 1;
-               }
-               if (do_symlink(file->u.link, buf) < 0
-                   && (errno != ENOENT || make_bak_dir(buf) < 0
-                    || do_symlink(file->u.link, buf) < 0)) {
-                       rsyserr(FERROR, errno, "link %s -> \"%s\"",
-                               full_fname(buf), safe_fname(file->u.link));
+                       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;
                }
-               do_unlink(fname);
-               kept = 1;
        }
 #endif
 
-       if (!kept && !S_ISREG(file->mode)) {
-               rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
-                       safe_fname(fname));
-               return 1;
+       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 2;
        }
 
-       /* move to keep tree if a file */
-       if (!kept) {
-               if (robust_move(fname, buf) != 0) {
+       /* 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), safe_fname(buf));
-               } else if (st.st_nlink > 1) {
-                       /* If someone has hard-linked the file into the backup
-                        * dir, rename() might return success but do nothing! */
-                       robust_unlink(fname); /* Just in case... */
+                               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;
        }
-       set_perms(buf, file, NULL, 0);
-       free(file);
 
-       if (verbose > 1) {
-               rprintf(FINFO, "backed up %s to %s\n",
-                       safe_fname(fname), safe_fname(buf));
-       }
-       return 1;
-}
+       save_preserve_xattrs = preserve_xattrs;
+       preserve_xattrs = 0;
+       set_file_attrs(buf, file, NULL, fname, 0);
+       preserve_xattrs = save_preserve_xattrs;
 
+       unmake_file(file);
+#ifdef SUPPORT_ACLS
+       uncache_tmp_acls();
+#endif
+#ifdef SUPPORT_XATTRS
+       uncache_tmp_xattrs();
+#endif
 
-/* main backup switch routine */
-int make_backup(char *fname)
-{
-       if (backup_dir)
-               return keep_backup(fname);
-       return make_simple_backup(fname);
+  success:
+       if (INFO_GTE(BACKUP, 1))
+               rprintf(FINFO, "backed up %s to %s\n", fname, buf);
+       return ret;
 }