kernel/os/dkioc_free_util.c

   1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11
  12 /*
  13  * Copyright 2017 Nexenta Inc.  All rights reserved.
  14  */
  15
  16 /* needed when building libzpool */
  17 #ifndef _KERNEL
  18 #include <sys/zfs_context.h>
  19 #endif
  20
  21 #include <sys/sunddi.h>
  22 #include <sys/dkio.h>
  23 #include <sys/dkioc_free_util.h>
  24 #include <sys/sysmacros.h>
  25 #include <sys/file.h>
  26 #include <sys/sdt.h>
  27
  28 /*
  29  * Copy-in convenience function for variable-length dkioc_free_list_t
  30  * structures. The pointer to be copied from is in `arg' (may be a pointer
  31  * to userspace). A new buffer is allocated and a pointer to it is placed
  32  * in `out'. `ddi_flags' indicates whether the pointer is from user-
  33  * or kernelspace (FKIOCTL) and `kmflags' are the flags passed to
  34  * kmem_zalloc when allocating the new structure.
  35  * Returns 0 on success, or an errno on failure.
  36  */
  37 int
  38 dfl_copyin(void *arg, dkioc_free_list_t **out, int ddi_flags, int kmflags)
  39 {
  40         dkioc_free_list_t *dfl;
  41
  42         if (ddi_flags & FKIOCTL) {
  43                 dkioc_free_list_t *dfl_in = arg;
  44
  45                 if (dfl_in->dfl_num_exts == 0 ||
  46                     dfl_in->dfl_num_exts > DFL_COPYIN_MAX_EXTS)
  47                         return (SET_ERROR(EINVAL));
  48                 dfl = kmem_alloc(DFL_SZ(dfl_in->dfl_num_exts), kmflags);
  49                 if (dfl == NULL)
  50                         return (SET_ERROR(ENOMEM));
  51                 bcopy(dfl_in, dfl, DFL_SZ(dfl_in->dfl_num_exts));
  52         } else {
  53                 uint64_t num_exts;
  54
  55                 if (ddi_copyin(((uint8_t *)arg) + offsetof(dkioc_free_list_t,
  56                     dfl_num_exts), &num_exts, sizeof (num_exts),
  57                     ddi_flags) != 0)
  58                         return (SET_ERROR(EFAULT));
  59                 if (num_exts == 0 || num_exts > DFL_COPYIN_MAX_EXTS)
  60                         return (SET_ERROR(EINVAL));
  61                 dfl = kmem_alloc(DFL_SZ(num_exts), kmflags);
  62                 if (dfl == NULL)
  63                         return (SET_ERROR(ENOMEM));
  64                 if (ddi_copyin(arg, dfl, DFL_SZ(num_exts), ddi_flags) != 0 ||
  65                     dfl->dfl_num_exts != num_exts) {
  66                         kmem_free(dfl, DFL_SZ(num_exts));
  67                         return (SET_ERROR(EFAULT));
  68                 }
  69         }
  70
  71         *out = dfl;
  72         return (0);
  73 }
  74
  75 /* Frees a variable-length dkioc_free_list_t structure. */
  76 void
  77 dfl_free(dkioc_free_list_t *dfl)
  78 {
  79         kmem_free(dfl, DFL_SZ(dfl->dfl_num_exts));
  80 }