qemu/fsdev/9p-iov-marshal.c
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   1/*
   2 * 9p backend
   3 *
   4 * Copyright IBM, Corp. 2010
   5 *
   6 * Authors:
   7 *  Anthony Liguori   <aliguori@us.ibm.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2.  See
  10 * the COPYING file in the top-level directory.
  11 *
  12 */
  13
  14#include "qemu/osdep.h"
  15#include <glib/gprintf.h>
  16#include <utime.h>
  17
  18#include "9p-iov-marshal.h"
  19#include "qemu/bswap.h"
  20
  21static ssize_t v9fs_packunpack(void *addr, struct iovec *sg, int sg_count,
  22                               size_t offset, size_t size, int pack)
  23{
  24    int i = 0;
  25    size_t copied = 0;
  26    size_t req_size = size;
  27
  28
  29    for (i = 0; size && i < sg_count; i++) {
  30        size_t len;
  31        if (offset >= sg[i].iov_len) {
  32            /* skip this sg */
  33            offset -= sg[i].iov_len;
  34            continue;
  35        } else {
  36            len = MIN(sg[i].iov_len - offset, size);
  37            if (pack) {
  38                memcpy(sg[i].iov_base + offset, addr, len);
  39            } else {
  40                memcpy(addr, sg[i].iov_base + offset, len);
  41            }
  42            size -= len;
  43            copied += len;
  44            addr += len;
  45            if (size) {
  46                offset = 0;
  47                continue;
  48            }
  49        }
  50    }
  51    if (copied < req_size) {
  52        /*
  53         * We copied less that requested size. error out
  54         */
  55        return -ENOBUFS;
  56    }
  57    return copied;
  58}
  59
  60static ssize_t v9fs_unpack(void *dst, struct iovec *out_sg, int out_num,
  61                           size_t offset, size_t size)
  62{
  63    return v9fs_packunpack(dst, out_sg, out_num, offset, size, 0);
  64}
  65
  66ssize_t v9fs_pack(struct iovec *in_sg, int in_num, size_t offset,
  67                  const void *src, size_t size)
  68{
  69    return v9fs_packunpack((void *)src, in_sg, in_num, offset, size, 1);
  70}
  71
  72ssize_t v9fs_iov_vunmarshal(struct iovec *out_sg, int out_num, size_t offset,
  73                            int bswap, const char *fmt, va_list ap)
  74{
  75    int i;
  76    ssize_t copied = 0;
  77    size_t old_offset = offset;
  78
  79    for (i = 0; fmt[i]; i++) {
  80        switch (fmt[i]) {
  81        case 'b': {
  82            uint8_t *valp = va_arg(ap, uint8_t *);
  83            copied = v9fs_unpack(valp, out_sg, out_num, offset, sizeof(*valp));
  84            break;
  85        }
  86        case 'w': {
  87            uint16_t val, *valp;
  88            valp = va_arg(ap, uint16_t *);
  89            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
  90            if (bswap) {
  91                *valp = le16_to_cpu(val);
  92            } else {
  93                *valp = val;
  94            }
  95            break;
  96        }
  97        case 'd': {
  98            uint32_t val, *valp;
  99            valp = va_arg(ap, uint32_t *);
 100            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 101            if (bswap) {
 102                *valp = le32_to_cpu(val);
 103            } else {
 104                *valp = val;
 105            }
 106            break;
 107        }
 108        case 'q': {
 109            uint64_t val, *valp;
 110            valp = va_arg(ap, uint64_t *);
 111            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 112            if (bswap) {
 113                *valp = le64_to_cpu(val);
 114            } else {
 115                *valp = val;
 116            }
 117            break;
 118        }
 119        case 's': {
 120            V9fsString *str = va_arg(ap, V9fsString *);
 121            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 122                                        "w", &str->size);
 123            if (copied > 0) {
 124                offset += copied;
 125                str->data = g_malloc(str->size + 1);
 126                copied = v9fs_unpack(str->data, out_sg, out_num, offset,
 127                                     str->size);
 128                if (copied >= 0) {
 129                    str->data[str->size] = 0;
 130                } else {
 131                    v9fs_string_free(str);
 132                }
 133            }
 134            break;
 135        }
 136        case 'Q': {
 137            V9fsQID *qidp = va_arg(ap, V9fsQID *);
 138            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 139                                        "bdq", &qidp->type, &qidp->version,
 140                                        &qidp->path);
 141            break;
 142        }
 143        case 'S': {
 144            V9fsStat *statp = va_arg(ap, V9fsStat *);
 145            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 146                                        "wwdQdddqsssssddd",
 147                                        &statp->size, &statp->type,
 148                                        &statp->dev, &statp->qid,
 149                                        &statp->mode, &statp->atime,
 150                                        &statp->mtime, &statp->length,
 151                                        &statp->name, &statp->uid,
 152                                        &statp->gid, &statp->muid,
 153                                        &statp->extension,
 154                                        &statp->n_uid, &statp->n_gid,
 155                                        &statp->n_muid);
 156            break;
 157        }
 158        case 'I': {
 159            V9fsIattr *iattr = va_arg(ap, V9fsIattr *);
 160            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 161                                        "ddddqqqqq",
 162                                        &iattr->valid, &iattr->mode,
 163                                        &iattr->uid, &iattr->gid,
 164                                        &iattr->size, &iattr->atime_sec,
 165                                        &iattr->atime_nsec,
 166                                        &iattr->mtime_sec,
 167                                        &iattr->mtime_nsec);
 168            break;
 169        }
 170        default:
 171            g_assert_not_reached();
 172        }
 173        if (copied < 0) {
 174            return copied;
 175        }
 176        offset += copied;
 177    }
 178
 179    return offset - old_offset;
 180}
 181
 182ssize_t v9fs_iov_unmarshal(struct iovec *out_sg, int out_num, size_t offset,
 183                           int bswap, const char *fmt, ...)
 184{
 185    ssize_t ret;
 186    va_list ap;
 187
 188    va_start(ap, fmt);
 189    ret = v9fs_iov_vunmarshal(out_sg, out_num, offset, bswap, fmt, ap);
 190    va_end(ap);
 191
 192    return ret;
 193}
 194
 195ssize_t v9fs_iov_vmarshal(struct iovec *in_sg, int in_num, size_t offset,
 196                          int bswap, const char *fmt, va_list ap)
 197{
 198    int i;
 199    ssize_t copied = 0;
 200    size_t old_offset = offset;
 201
 202    for (i = 0; fmt[i]; i++) {
 203        switch (fmt[i]) {
 204        case 'b': {
 205            uint8_t val = va_arg(ap, int);
 206            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 207            break;
 208        }
 209        case 'w': {
 210            uint16_t val = va_arg(ap, int);
 211            if (bswap) {
 212                val = cpu_to_le16(val);
 213            }
 214            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 215            break;
 216        }
 217        case 'd': {
 218            uint32_t val = va_arg(ap, uint32_t);
 219            if (bswap) {
 220                val = cpu_to_le32(val);
 221            }
 222            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 223            break;
 224        }
 225        case 'q': {
 226            uint64_t val = va_arg(ap, uint64_t);
 227            if (bswap) {
 228                val = cpu_to_le64(val);
 229            }
 230            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 231            break;
 232        }
 233        case 's': {
 234            V9fsString *str = va_arg(ap, V9fsString *);
 235            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap,
 236                                      "w", str->size);
 237            if (copied > 0) {
 238                offset += copied;
 239                copied = v9fs_pack(in_sg, in_num, offset, str->data, str->size);
 240            }
 241            break;
 242        }
 243        case 'Q': {
 244            V9fsQID *qidp = va_arg(ap, V9fsQID *);
 245            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap, "bdq",
 246                                      qidp->type, qidp->version,
 247                                      qidp->path);
 248            break;
 249        }
 250        case 'S': {
 251            V9fsStat *statp = va_arg(ap, V9fsStat *);
 252            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap,
 253                                      "wwdQdddqsssssddd",
 254                                      statp->size, statp->type, statp->dev,
 255                                      &statp->qid, statp->mode, statp->atime,
 256                                      statp->mtime, statp->length,
 257                                      &statp->name,
 258                                      &statp->uid, &statp->gid, &statp->muid,
 259                                      &statp->extension, statp->n_uid,
 260                                      statp->n_gid, statp->n_muid);
 261            break;
 262        }
 263        case 'A': {
 264            V9fsStatDotl *statp = va_arg(ap, V9fsStatDotl *);
 265            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap,
 266                                      "qQdddqqqqqqqqqqqqqqq",
 267                                      statp->st_result_mask,
 268                                      &statp->qid, statp->st_mode,
 269                                      statp->st_uid, statp->st_gid,
 270                                      statp->st_nlink, statp->st_rdev,
 271                                      statp->st_size, statp->st_blksize,
 272                                      statp->st_blocks, statp->st_atime_sec,
 273                                      statp->st_atime_nsec,
 274                                      statp->st_mtime_sec,
 275                                      statp->st_mtime_nsec,
 276                                      statp->st_ctime_sec,
 277                                      statp->st_ctime_nsec,
 278                                      statp->st_btime_sec,
 279                                      statp->st_btime_nsec, statp->st_gen,
 280                                      statp->st_data_version);
 281            break;
 282        }
 283        default:
 284            g_assert_not_reached();
 285        }
 286        if (copied < 0) {
 287            return copied;
 288        }
 289        offset += copied;
 290    }
 291
 292    return offset - old_offset;
 293}
 294
 295ssize_t v9fs_iov_marshal(struct iovec *in_sg, int in_num, size_t offset,
 296                         int bswap, const char *fmt, ...)
 297{
 298    ssize_t ret;
 299    va_list ap;
 300
 301    va_start(ap, fmt);
 302    ret = v9fs_iov_vmarshal(in_sg, in_num, offset, bswap, fmt, ap);
 303    va_end(ap);
 304
 305    return ret;
 306}
 307