backup.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1999
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 /* backup handling code */
  20
  21 #include "rsync.h"
  22
  23 extern int verbose;
  24 extern char *backup_suffix;
  25 extern char *backup_dir;
  26
  27
  28 extern int am_root;
  29 extern int preserve_devices;
  30 extern int preserve_links;
  31 extern int preserve_hard_links;
  32
  33 /* simple backup creates a backup with a suffix in the same directory */
  34 static int make_simple_backup(char *fname)
  35 {
  36         char fnamebak[MAXPATHLEN];
  37         if (strlen(fname) + strlen(backup_suffix) > (MAXPATHLEN-1)) {
  38                 rprintf(FERROR,"backup filename too long\n");
  39                 return 0;
  40         }
  41
  42         snprintf(fnamebak,sizeof(fnamebak),"%s%s",fname,backup_suffix);
  43         if (do_rename(fname,fnamebak) != 0) {
  44                 /* cygwin (at least version b19) reports EINVAL */
  45                 if (errno != ENOENT && errno != EINVAL) {
  46                         rsyserr(FERROR, errno, "rename %s to backup %s", fname, fnamebak);
  47                         return 0;
  48                 }
  49         } else if (verbose > 1) {
  50                 rprintf(FINFO,"backed up %s to %s\n",fname,fnamebak);
  51         }
  52         return 1;
  53 }
  54
  55
  56 /* recursively make a directory path */
  57 static int make_dir(char *name, int mask)
  58 {
  59         char newdir [MAXPATHLEN];
  60         char *p, *d;
  61
  62         /* copy pathname over, look for last '/' */
  63         for (p = d = newdir; *name; *d++ = *name++)
  64                 if (*name == '/')
  65                         p = d;
  66         if (p == newdir)
  67                 return 0;
  68         *p = 0;
  69
  70         /* make the new directory, if that fails then make its parent */
  71         while (do_mkdir (newdir, mask) != 0)
  72                 if ((errno != ENOENT) || !make_dir (newdir, mask))
  73                         return 0;
  74
  75         return 1;
  76 } /* make_dir */
  77
  78
  79 /****************************************************************************
  80 Create a directory given an absolute path, perms based upon another directory
  81 path
  82 ****************************************************************************/
  83 static int make_bak_dir(char *fname,char *bak_path)
  84 {
  85         STRUCT_STAT st;
  86         STRUCT_STAT *st2;
  87         char fullpath[MAXPATHLEN];
  88         extern int orig_umask;
  89         char *p;
  90         char *q;
  91
  92         while(strncmp(bak_path,"./",2)==0) bak_path += 2;
  93
  94         if(bak_path[strlen(bak_path)-1]!='/') {
  95                 snprintf(fullpath,sizeof(fullpath),"%s/",bak_path);
  96         } else {
  97                 snprintf(fullpath,sizeof(fullpath),"%s",bak_path);
  98         }
  99         p=fullpath;
 100         q=&fullpath[strlen(fullpath)];  /* End of bak_path string */
 101         strcat(fullpath,fname);
 102
 103         /* Make the directories */
 104         while ((p=strchr(p,'/'))) {
 105                 *p = 0;
 106                 if(do_lstat(fullpath,&st)!=0) {
 107                         do_mkdir(fullpath,0777 & ~orig_umask);
 108                         if(p>q) {
 109                                 if(do_lstat(q,&st)!=0) {
 110                                         rprintf(FERROR,"make_bak_dir stat %s : %s\n",fullpath,strerror(errno));
 111                                 } else {
 112                                         st2=&st;
 113                                         set_modtime(fullpath,st2->st_mtime);
 114                                         if(do_lchown(fullpath,st2->st_uid,st2->st_gid)!=0) {
 115                                                 rprintf(FERROR,"make_bak_dir chown %s : %s\n",fullpath,strerror(errno));
 116                                         };
 117                                         if(do_chmod(fullpath,st2->st_mode)!=0) {
 118                                                 rprintf(FERROR,"make_bak_dir failed to set permissions on %s : %s\n",fullpath,strerror(errno));
 119                                         };
 120                                 };
 121                         }
 122                 };
 123                 *p = '/';
 124                 p++;
 125         }
 126         return 0;
 127 }
 128
 129 /* robustly move a file, creating new directory structures if necessary */
 130 static int robust_move(char *src, char *dst)
 131 {
 132         int keep_trying = 4;
 133         int keep_path_extfs = 0;
 134         int failed;
 135
 136         while (keep_trying) {
 137                 if (keep_path_extfs) {
 138                         failed = copy_file(src, dst, 0755);
 139                         if (!failed) {
 140                                 do_unlink(src);
 141                         }
 142                 } else {
 143                         failed = robust_rename (src, dst);
 144                 }
 145
 146                 if (failed) {
 147                         if (verbose > 2)
 148                                 rprintf (FERROR, "robust_move failed: %s(%d)\n",
 149                                         strerror (errno), errno);
 150                         switch (errno) {
 151                                 /* external filesystem */
 152                                 case EXDEV:
 153                                         keep_path_extfs = 1;
 154                                         keep_trying--;
 155                                         break;
 156                                 /* no directory to write to */
 157                                 case ENOENT:
 158                                         make_dir (dst, 0755);
 159                                         keep_trying--;
 160                                         break;
 161                                 default:
 162                                         keep_trying = 0;
 163                         } /* switch */
 164                 } else
 165                         keep_trying = 0;
 166         } /* while */
 167         return (!failed);
 168 } /* robust_move */
 169
 170
 171 /* if we have a backup_dir, then we get here from make_backup().
 172    We will move the file to be deleted into a parallel directory tree */
 173 static int keep_backup(char *fname)
 174 {
 175
 176         static int initialised;
 177
 178         char keep_name [MAXPATHLEN];
 179         STRUCT_STAT st;
 180         struct file_struct *file;
 181
 182         int kept=0;
 183         int ret_code;
 184
 185         if (!initialised) {
 186                 if (backup_dir[strlen(backup_dir) - 1] == '/')
 187                         backup_dir[strlen(backup_dir) - 1] = 0;
 188                 if (verbose > 0)
 189                         rprintf (FINFO, "backup_dir is %s\n", backup_dir);
 190                 initialised = 1;
 191         }
 192
 193         /* return if no file to keep */
 194 #if SUPPORT_LINKS
 195         if (do_lstat (fname, &st)) return 1;
 196 #else
 197         if (do_stat (fname, &st)) return 1;
 198 #endif
 199
 200         file = make_file(-1, fname, NULL, 1);
 201
 202         /* the file could have disappeared */
 203         if (!file) return 1;
 204
 205         /* make a complete pathname for backup file */
 206         if (strlen(backup_dir) + strlen(fname) > (MAXPATHLEN - 1)) {
 207                 rprintf (FERROR, "keep_backup filename too long\n");
 208                 return 0;
 209         }
 210
 211         snprintf(keep_name, sizeof (keep_name), "%s/%s", backup_dir, fname);
 212
 213
 214 #ifdef HAVE_MKNOD
 215         /* Check to see if this is a device file, or link */
 216         if(IS_DEVICE(file->mode)) {
 217                 if(am_root && preserve_devices) {
 218                         make_bak_dir(fname,backup_dir);
 219                         if(do_mknod(keep_name,file->mode,file->rdev)!=0) {
 220                                 rprintf(FERROR,"mknod %s : %s\n",keep_name,strerror(errno));
 221                         } else {
 222                                 if(verbose>2)
 223                                         rprintf(FINFO,"make_backup : DEVICE %s successful.\n",fname);
 224                         };
 225                 };
 226                 kept=1;
 227                 do_unlink(fname);
 228         };
 229 #endif
 230
 231         if(!kept && S_ISDIR(file->mode)) {
 232                 /* make an empty directory */
 233                 make_bak_dir(fname,backup_dir);
 234                 do_mkdir(keep_name,file->mode);
 235                 ret_code=do_rmdir(fname);
 236                 if(verbose>2)
 237                         rprintf(FINFO,"make_backup : RMDIR %s returns %i\n",fname,ret_code);
 238                 kept=1;
 239         };
 240
 241 #if SUPPORT_LINKS
 242         if(!kept && preserve_links && S_ISLNK(file->mode)) {
 243                 extern int safe_symlinks;
 244                 if (safe_symlinks && unsafe_symlink(file->link, keep_name)) {
 245                         if (verbose) {
 246                                 rprintf(FINFO,"ignoring unsafe symlink %s -> %s\n",
 247                                         keep_name,file->link);
 248                         }
 249                         kept=1;
 250                 }
 251                 make_bak_dir(fname,backup_dir);
 252                 if(do_symlink(file->link,keep_name) != 0) {
 253                         rprintf(FERROR,"link %s -> %s : %s\n",keep_name,file->link,strerror(errno));
 254                 };
 255                 do_unlink(fname);
 256                 kept=1;
 257         };
 258 #endif
 259         if(!kept && preserve_hard_links && check_hard_link(file)) {
 260                 if(verbose > 1) rprintf(FINFO,"%s is a hard link\n",f_name(file));
 261         };
 262
 263         if(!kept && !S_ISREG(file->mode)) {
 264                 rprintf(FINFO,"make_bak: skipping non-regular file %s\n",fname);
 265         }
 266
 267         /* move to keep tree if a file */
 268         if(!kept) {
 269                 if (!robust_move (fname, keep_name))
 270                         rprintf(FERROR, "keep_backup failed %s -> %s : %s\n",
 271                                 fname, keep_name, strerror(errno));
 272         };
 273         set_perms (keep_name, file, NULL, 0);
 274         free_file (file);
 275         free (file);
 276
 277         if (verbose > 1)
 278                 rprintf (FINFO, "keep_backup %s -> %s\n", fname, keep_name);
 279         return 1;
 280 } /* keep_backup */
 281
 282
 283 /* main backup switch routine */
 284 int make_backup(char *fname)
 285 {
 286         if (backup_dir)
 287                 return (keep_backup(fname));
 288         else
 289                 return (make_simple_backup(fname));
 290 }
 291