source4/ntvfs/posix/pvfs_read.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    POSIX NTVFS backend - read
   5
   6    Copyright (C) Andrew Tridgell 2004
   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 "vfs_posix.h"
  24 #include "lib/events/events.h"
  25
  26 /*
  27   read from a file
  28 */
  29 NTSTATUS pvfs_read(struct ntvfs_module_context *ntvfs,
  30                    struct ntvfs_request *req, union smb_read *rd)
  31 {
  32         struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
  33                                   struct pvfs_state);
  34         ssize_t ret;
  35         struct pvfs_file *f;
  36         NTSTATUS status;
  37         uint32_t maxcnt;
  38         uint32_t mask;
  39
  40         if (rd->generic.level != RAW_READ_READX) {
  41                 return ntvfs_map_read(ntvfs, req, rd);
  42         }
  43
  44         f = pvfs_find_fd(pvfs, req, rd->readx.in.file.ntvfs);
  45         if (!f) {
  46                 return NT_STATUS_INVALID_HANDLE;
  47         }
  48
  49         if (f->handle->fd == -1) {
  50                 return NT_STATUS_INVALID_DEVICE_REQUEST;
  51         }
  52
  53         mask = SEC_FILE_READ_DATA;
  54         if (rd->readx.in.read_for_execute) {
  55                 mask |= SEC_FILE_EXECUTE;
  56         }
  57         if (!(f->access_mask & mask)) {
  58                 return NT_STATUS_ACCESS_DENIED;
  59         }
  60
  61         maxcnt = rd->readx.in.maxcnt;
  62         if (maxcnt > 2*UINT16_MAX && req->ctx->protocol < PROTOCOL_SMB2_02) {
  63                 DEBUG(3,(__location__ ": Invalid SMB maxcnt 0x%x\n", maxcnt));
  64                 return NT_STATUS_INVALID_PARAMETER;
  65         }
  66
  67         status = pvfs_check_lock(pvfs, f, req->smbpid,
  68                                  rd->readx.in.offset,
  69                                  maxcnt,
  70                                  READ_LOCK);
  71         if (!NT_STATUS_IS_OK(status)) {
  72                 return status;
  73         }
  74
  75         if (f->handle->name->stream_name) {
  76                 ret = pvfs_stream_read(pvfs, f->handle,
  77                                        rd->readx.out.data, maxcnt, rd->readx.in.offset);
  78         } else {
  79 #if HAVE_LINUX_AIO
  80                 /* possibly try an aio read */
  81                 if ((req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC) &&
  82                     (pvfs->flags & PVFS_FLAG_LINUX_AIO)) {
  83                         status = pvfs_aio_pread(req, rd, f, maxcnt);
  84                         if (NT_STATUS_IS_OK(status)) {
  85                                 return NT_STATUS_OK;
  86                         }
  87                 }
  88 #endif
  89                 ret = pread(f->handle->fd,
  90                             rd->readx.out.data,
  91                             maxcnt,
  92                             rd->readx.in.offset);
  93         }
  94         if (ret == -1) {
  95                 return pvfs_map_errno(pvfs, errno);
  96         }
  97
  98         /* only SMB2 honors mincnt */
  99         if (req->ctx->protocol >= PROTOCOL_SMB2_02) {
 100                 if (rd->readx.in.mincnt > ret ||
 101                     (ret == 0 && maxcnt > 0)) {
 102                         return NT_STATUS_END_OF_FILE;
 103                 }
 104         }
 105
 106         f->handle->position = f->handle->seek_offset = rd->readx.in.offset + ret;
 107
 108         rd->readx.out.nread = ret;
 109         rd->readx.out.remaining = 0xFFFF;
 110         rd->readx.out.compaction_mode = 0;
 111
 112         return NT_STATUS_OK;
 113 }