src/afs/afs_osi_uio.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 #include <afsconfig.h>
  11 #include "afs/param.h"
  12
  13
  14 #include "afs/sysincludes.h"    /* Standard vendor system headers */
  15 #include "afsincludes.h"        /* Afs-based standard headers */
  16 #include "afs/afs_stats.h"      /* statistics */
  17 #include "afs/afs_cbqueue.h"
  18 #include "afs/nfsclient.h"
  19 #include "afs/afs_osidnlc.h"
  20
  21
  22 /*
  23  * UIO routines
  24  */
  25
  26 #ifndef AFS_DARWIN80_ENV
  27 /* routine to make copy of uio structure in ainuio, using aoutvec for space */
  28 int
  29 afsio_copy(struct uio *ainuio, struct uio *aoutuio,
  30            struct iovec *aoutvec)
  31 {
  32     int i;
  33     struct iovec *tvec;
  34
  35     AFS_STATCNT(afsio_copy);
  36     if (ainuio->afsio_iovcnt > AFS_MAXIOVCNT)
  37         return EINVAL;
  38     memcpy((char *)aoutuio, (char *)ainuio, sizeof(struct uio));
  39     tvec = ainuio->afsio_iov;
  40     aoutuio->afsio_iov = aoutvec;
  41     for (i = 0; i < ainuio->afsio_iovcnt; i++) {
  42         memcpy((char *)aoutvec, (char *)tvec, sizeof(struct iovec));
  43         tvec++;                 /* too many compiler bugs to do this as one expr */
  44         aoutvec++;
  45     }
  46     return 0;
  47 }
  48
  49 /* trim the uio structure to the specified size */
  50 int
  51 afsio_trim(struct uio *auio, afs_int32 asize)
  52 {
  53     int i;
  54     struct iovec *tv;
  55
  56     AFS_STATCNT(afsio_trim);
  57     auio->afsio_resid = asize;
  58     tv = auio->afsio_iov;
  59     /* It isn't clear that multiple iovecs work ok (hasn't been tested!) */
  60     for (i = 0;; i++, tv++) {
  61         if (i >= auio->afsio_iovcnt || asize <= 0) {
  62             /* we're done */
  63             auio->afsio_iovcnt = i;
  64             break;
  65         }
  66         if (tv->iov_len <= asize)
  67             /* entire iovec is included */
  68             asize -= tv->iov_len;       /* this many fewer bytes */
  69         else {
  70             /* this is the last one */
  71             tv->iov_len = asize;
  72             auio->afsio_iovcnt = i + 1;
  73             break;
  74         }
  75     }
  76     return 0;
  77 }
  78
  79 /* Allocate space for, then partially copy, over an existing iovec up to the
  80  * length given in len.
  81  *
  82  * This requires that SmallSpace can alloc space big enough to hold a struct
  83  * UIO, plus 16 iovecs
  84  */
  85
  86 struct uio *
  87 afsio_partialcopy(struct uio *auio, size_t len) {
  88     char *space;
  89     struct uio *newuio;
  90     struct iovec *newvec;
  91     size_t space_len = sizeof(struct uio) +
  92                        sizeof(struct iovec) * AFS_MAXIOVCNT;
  93
  94     /* Allocate a block that can contain both the UIO and the iovec */
  95     space = osi_AllocSmallSpace(space_len);
  96     memset(space, 0, space_len);
  97
  98     newuio = (struct uio *) space;
  99     newvec = (struct iovec *) (space + sizeof(struct uio));
 100
 101     afsio_copy(auio, newuio, newvec);
 102     afsio_trim(newuio, len);
 103
 104     return newuio;
 105 }
 106
 107 void
 108 afsio_free(struct uio *uio) {
 109     osi_FreeSmallSpace(uio);
 110 }
 111 #endif
 112
 113 /* skip asize bytes in the current uio structure */
 114 int
 115 afsio_skip(struct uio *auio, afs_int32 asize)
 116 {
 117     struct iovec *tv;   /* pointer to current iovec */
 118     int cnt;
 119
 120     AFS_STATCNT(afsio_skip);
 121 #ifdef AFS_DARWIN80_ENV
 122     uio_update(auio, asize);
 123 #else
 124     /* It isn't guaranteed that multiple iovecs work ok (hasn't been tested!) */
 125     while (asize > 0 && auio->afsio_resid) {
 126         tv = auio->afsio_iov;
 127         cnt = tv->iov_len;
 128         if (cnt == 0) {
 129             auio->afsio_iov++;
 130             auio->afsio_iovcnt--;
 131             continue;
 132         }
 133         if (cnt > asize)
 134             cnt = asize;
 135         tv->iov_base = (char *)(tv->iov_base) + cnt;
 136         tv->iov_len -= cnt;
 137         auio->uio_resid -= cnt;
 138         auio->afsio_offset += cnt;
 139         asize -= cnt;
 140     }
 141 #endif
 142     return 0;
 143 }