Line data    Source code

       1             : /*
       2             :  SSSD
       3             : 
       4             :  Backup files
       5             : 
       6             :  Copyright (C) Simo Sorce       2009
       7             : 
       8             :  This program is free software; you can redistribute it and/or modify
       9             :  it under the terms of the GNU General Public License as published by
      10             :  the Free Software Foundation; either version 3 of the License, or
      11             :  (at your option) any later version.
      12             : 
      13             :  This program is distributed in the hope that it will be useful,
      14             :  but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      16             :  GNU General Public License for more details.
      17             : 
      18             :  You should have received a copy of the GNU General Public License
      19             :  along with this program.  If not, see <http://www.gnu.org/licenses/>.
      20             : */
      21             : 
      22             : #include "util/util.h"
      23             : #include <fcntl.h>
      24             : #include <stddef.h>
      25             : #include <stdlib.h>
      26             : 
      27             : #define BUFFER_SIZE 65536
      28             : 
      29           0 : int backup_file(const char *src_file, int dbglvl)
      30             : {
      31           0 :     TALLOC_CTX *tmp_ctx = NULL;
      32             :     char buf[BUFFER_SIZE];
      33           0 :     int src_fd = -1;
      34           0 :     int dst_fd = -1;
      35             :     char *dst_file;
      36             :     ssize_t numread;
      37             :     ssize_t written;
      38             :     int ret, i;
      39             : 
      40           0 :     src_fd = open(src_file, O_RDONLY);
      41           0 :     if (src_fd < 0) {
      42           0 :         ret = errno;
      43           0 :         DEBUG(dbglvl, "Error (%d [%s]) opening source file %s\n",
      44             :                        ret, strerror(ret), src_file);
      45           0 :         goto done;
      46             :     }
      47             : 
      48           0 :     tmp_ctx = talloc_new(NULL);
      49           0 :     if (!tmp_ctx) {
      50           0 :         ret = ENOMEM;
      51           0 :         goto done;
      52             :     }
      53             : 
      54             :     /* try a few times to come up with a new backup file, then give up */
      55           0 :     for (i = 0; i < 10; i++) {
      56           0 :         if (i == 0) {
      57           0 :             dst_file = talloc_asprintf(tmp_ctx, "%s.bak", src_file);
      58             :         } else {
      59           0 :             dst_file = talloc_asprintf(tmp_ctx, "%s.bak%d", src_file, i);
      60             :         }
      61           0 :         if (!dst_file) {
      62           0 :             ret = ENOMEM;
      63           0 :             goto done;
      64             :         }
      65             : 
      66           0 :         errno = 0;
      67           0 :         dst_fd = open(dst_file, O_CREAT|O_EXCL|O_WRONLY, 0600);
      68           0 :         ret = errno;
      69             : 
      70           0 :         if (dst_fd >= 0) break;
      71             : 
      72           0 :         if (ret != EEXIST) {
      73           0 :             DEBUG(dbglvl, "Error (%d [%s]) opening destination file %s\n",
      74             :                            ret, strerror(ret), dst_file);
      75           0 :             goto done;
      76             :         }
      77             :     }
      78           0 :     if (ret != 0) {
      79           0 :         DEBUG(dbglvl, "Error (%d [%s]) opening destination file %s\n",
      80             :                        ret, strerror(ret), dst_file);
      81           0 :         goto done;
      82             :     }
      83             : 
      84             :     /* copy file contents */
      85             :     while (1) {
      86           0 :         errno = 0;
      87           0 :         numread = sss_atomic_read_s(src_fd, buf, BUFFER_SIZE);
      88           0 :         if (numread < 0) {
      89           0 :             ret = errno;
      90           0 :             DEBUG(dbglvl, "Error (%d [%s]) reading from source %s\n",
      91             :                            ret, strerror(ret), src_file);
      92           0 :             goto done;
      93             :         }
      94           0 :         if (numread == 0) break;
      95             : 
      96           0 :         errno = 0;
      97           0 :         written = sss_atomic_write_s(dst_fd, buf, numread);
      98           0 :         if (written == -1) {
      99           0 :             ret = errno;
     100           0 :             DEBUG(dbglvl, "Error (%d [%s]) writing to destination %s\n",
     101             :                             ret, strerror(ret), dst_file);
     102           0 :             goto done;
     103             :         }
     104             : 
     105           0 :         if (written != numread) {
     106           0 :             DEBUG(dbglvl, "Wrote %zd bytes expected %zd bytes\n",
     107             :                   written, numread);
     108           0 :             ret = EIO;
     109           0 :             goto done;
     110             :         }
     111           0 :     }
     112             : 
     113           0 :     ret = EOK;
     114             : 
     115             : done:
     116           0 :     if (src_fd != -1) close(src_fd);
     117           0 :     if (dst_fd != -1) close(dst_fd);
     118           0 :     talloc_free(tmp_ctx);
     119           0 :     return ret;
     120             : }