source3/smbd/fd_handle.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    fd_handle structure handling
   4    Copyright (C) Ralph Boehme 2020
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "fd_handle.h"
  22
  23 struct fd_handle {
  24         size_t ref_count;
  25         int fd;
  26         uint64_t position_information;
  27         off_t pos;
  28         /*
  29          * NT Create options, but we only look at
  30          * NTCREATEX_FLAG_DENY_DOS and
  31          * NTCREATEX_FLAG_DENY_FCB.
  32          */
  33         uint32_t private_options;
  34         uint64_t gen_id;
  35 };
  36
  37 static int fd_handle_destructor(struct fd_handle *fh)
  38 {
  39         SMB_ASSERT((fh->fd == -1) || (fh->fd == AT_FDCWD));
  40         return 0;
  41 }
  42
  43 struct fd_handle *fd_handle_create(TALLOC_CTX *mem_ctx)
  44 {
  45         struct fd_handle *fh = NULL;
  46
  47         fh = talloc_zero(mem_ctx, struct fd_handle);
  48         if (fh == NULL) {
  49                 return NULL;
  50         }
  51         fh->fd = -1;
  52
  53         talloc_set_destructor(fh, fd_handle_destructor);
  54
  55         return fh;
  56 }
  57
  58 size_t fh_get_refcount(struct fd_handle *fh)
  59 {
  60         return fh->ref_count;
  61 }
  62
  63 void fh_set_refcount(struct fd_handle *fh, size_t ref_count)
  64 {
  65         fh->ref_count = ref_count;
  66 }
  67
  68 uint64_t fh_get_position_information(struct fd_handle *fh)
  69 {
  70         return fh->position_information;
  71 }
  72
  73 void fh_set_position_information(struct fd_handle *fh, uint64_t posinfo)
  74 {
  75         fh->position_information = posinfo;
  76 }
  77
  78 off_t fh_get_pos(struct fd_handle *fh)
  79 {
  80         return fh->pos;
  81 }
  82
  83 void fh_set_pos(struct fd_handle *fh, off_t pos)
  84 {
  85         fh->pos = pos;
  86 }
  87
  88 uint32_t fh_get_private_options(struct fd_handle *fh)
  89 {
  90         return fh->private_options;
  91 }
  92
  93 void fh_set_private_options(struct fd_handle *fh, uint32_t private_options)
  94 {
  95         fh->private_options = private_options;
  96 }
  97
  98 uint64_t fh_get_gen_id(struct fd_handle *fh)
  99 {
 100         return fh->gen_id;
 101 }
 102
 103 void fh_set_gen_id(struct fd_handle *fh, uint64_t gen_id)
 104 {
 105         fh->gen_id = gen_id;
 106 }
 107
 108 /****************************************************************************
 109  Helper functions for working with fsp->fh->fd
 110 ****************************************************************************/
 111
 112 int fsp_get_io_fd(const struct files_struct *fsp)
 113 {
 114         if (fsp->fsp_flags.is_pathref) {
 115                 DBG_ERR("fsp [%s] is a path referencing fsp\n",
 116                         fsp_str_dbg(fsp));
 117 #ifdef DEVELOPER
 118                 smb_panic("fsp is a pathref");
 119 #endif
 120                 return -1;
 121         }
 122
 123         return fsp->fh->fd;
 124 }
 125
 126 int fsp_get_pathref_fd(const struct files_struct *fsp)
 127 {
 128         return fsp->fh->fd;
 129 }
 130
 131 void fsp_set_fd(struct files_struct *fsp, int fd)
 132 {
 133         /*
 134          * Deliberately allow setting an fd if the existing fd is the
 135          * same. This happens if a VFS module assigns the fd to
 136          * fsp->fh->fd in its openat VFS function. The canonical place
 137          * where the assignment is done is in fd_open(), but some VFS
 138          * modules do it anyway.
 139          */
 140
 141         SMB_ASSERT(fsp->fh->fd == -1 ||
 142                    fsp->fh->fd == fd ||
 143                    fd == -1 ||
 144                    fd == AT_FDCWD);
 145
 146         fsp->fh->fd = fd;
 147 }