source3/lib/file_id.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    file_id structure handling
   5
   6    Copyright (C) Andrew Tridgell 2007
   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 "includes.h"
  23 #include "lib/file_id.h"
  24
  25 /*
  26   return True if two file_id structures are equal
  27  */
  28 bool file_id_equal(const struct file_id *id1, const struct file_id *id2)
  29 {
  30         return id1->inode == id2->inode && id1->devid == id2->devid &&
  31             id1->extid == id2->extid;
  32 }
  33
  34 char *file_id_str_buf(struct file_id fid, struct file_id_buf *dst)
  35 {
  36         snprintf(dst->buf,
  37                  sizeof(dst->buf),
  38                  "%"PRIu64":%"PRIu64":%"PRIu64,
  39                  fid.devid,
  40                  fid.inode,
  41                  fid.extid);
  42         return dst->buf;
  43 }
  44
  45 /*
  46   push a 16 byte version of a file id into a buffer.  This ignores the extid
  47   and is needed when dev/inodes are stored in persistent storage (tdbs).
  48  */
  49 void push_file_id_16(char *buf, const struct file_id *id)
  50 {
  51         SIVAL(buf,  0, id->devid&0xFFFFFFFF);
  52         SIVAL(buf,  4, id->devid>>32);
  53         SIVAL(buf,  8, id->inode&0xFFFFFFFF);
  54         SIVAL(buf, 12, id->inode>>32);
  55 }
  56
  57 /*
  58   push a 24 byte version of a file id into a buffer
  59  */
  60 void push_file_id_24(char *buf, const struct file_id *id)
  61 {
  62         SIVAL(buf,  0, id->devid&0xFFFFFFFF);
  63         SIVAL(buf,  4, id->devid>>32);
  64         SIVAL(buf,  8, id->inode&0xFFFFFFFF);
  65         SIVAL(buf, 12, id->inode>>32);
  66         SIVAL(buf, 16, id->extid&0xFFFFFFFF);
  67         SIVAL(buf, 20, id->extid>>32);
  68 }
  69
  70 /*
  71   pull a 24 byte version of a file id from a buffer
  72  */
  73 void pull_file_id_24(const char *buf, struct file_id *id)
  74 {
  75         ZERO_STRUCTP(id);
  76         id->devid  = IVAL(buf,  0);
  77         id->devid |= ((uint64_t)IVAL(buf,4))<<32;
  78         id->inode  = IVAL(buf,  8);
  79         id->inode |= ((uint64_t)IVAL(buf,12))<<32;
  80         id->extid  = IVAL(buf,  16);
  81         id->extid |= ((uint64_t)IVAL(buf,20))<<32;
  82 }
  83
  84 uint64_t make_file_id_from_itime(SMB_STRUCT_STAT *st)
  85 {
  86         struct timespec itime = st->st_ex_itime;
  87         ino_t ino = st->st_ex_ino;
  88         uint64_t file_id_low;
  89         uint64_t file_id;
  90
  91         if (st->st_ex_iflags & ST_EX_IFLAG_CALCULATED_ITIME) {
  92                 return ino;
  93         }
  94
  95         round_timespec_to_nttime(&itime);
  96
  97         file_id_low = itime.tv_nsec;
  98         if (file_id_low == 0) {
  99                 /*
 100                  * This could be by coincidence, but more likely the filesystem
 101                  * is only giving us seconds granularity. We need more fine
 102                  * grained granularity for the File-ID, so combine with the
 103                  * inode number.
 104                  */
 105                 file_id_low = ino & ((1 << 30) - 1);
 106         }
 107
 108         /*
 109          * Set the high bit so ideally File-IDs based on inode numbers and
 110          * File-IDs based on Birth Time use disjoint ranges, given inodes never
 111          * have the high bit set.
 112          */
 113         file_id = ((uint64_t)1) << 63;
 114         file_id |= (uint64_t)itime.tv_sec << 30;
 115         file_id |= file_id_low;
 116
 117         return file_id;
 118 }