qemu/fsdev/virtio-9p-marshal.c
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   1/*
   2 * Virtio 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 <glib.h>
  15#include <glib/gprintf.h>
  16#include <sys/types.h>
  17#include <dirent.h>
  18#include <sys/time.h>
  19#include <utime.h>
  20#include <sys/uio.h>
  21#include <string.h>
  22#include <stdint.h>
  23#include <errno.h>
  24
  25#include "qemu/compiler.h"
  26#include "virtio-9p-marshal.h"
  27#include "qemu/bswap.h"
  28
  29void v9fs_string_free(V9fsString *str)
  30{
  31    g_free(str->data);
  32    str->data = NULL;
  33    str->size = 0;
  34}
  35
  36void v9fs_string_null(V9fsString *str)
  37{
  38    v9fs_string_free(str);
  39}
  40
  41void GCC_FMT_ATTR(2, 3)
  42v9fs_string_sprintf(V9fsString *str, const char *fmt, ...)
  43{
  44    va_list ap;
  45
  46    v9fs_string_free(str);
  47
  48    va_start(ap, fmt);
  49    str->size = g_vasprintf(&str->data, fmt, ap);
  50    va_end(ap);
  51}
  52
  53void v9fs_string_copy(V9fsString *lhs, V9fsString *rhs)
  54{
  55    v9fs_string_free(lhs);
  56    v9fs_string_sprintf(lhs, "%s", rhs->data);
  57}
  58
  59
  60static ssize_t v9fs_packunpack(void *addr, struct iovec *sg, int sg_count,
  61                               size_t offset, size_t size, int pack)
  62{
  63    int i = 0;
  64    size_t copied = 0;
  65    size_t req_size = size;
  66
  67
  68    for (i = 0; size && i < sg_count; i++) {
  69        size_t len;
  70        if (offset >= sg[i].iov_len) {
  71            /* skip this sg */
  72            offset -= sg[i].iov_len;
  73            continue;
  74        } else {
  75            len = MIN(sg[i].iov_len - offset, size);
  76            if (pack) {
  77                memcpy(sg[i].iov_base + offset, addr, len);
  78            } else {
  79                memcpy(addr, sg[i].iov_base + offset, len);
  80            }
  81            size -= len;
  82            copied += len;
  83            addr += len;
  84            if (size) {
  85                offset = 0;
  86                continue;
  87            }
  88        }
  89    }
  90    if (copied < req_size) {
  91        /*
  92         * We copied less that requested size. error out
  93         */
  94        return -ENOBUFS;
  95    }
  96    return copied;
  97}
  98
  99static ssize_t v9fs_unpack(void *dst, struct iovec *out_sg, int out_num,
 100                           size_t offset, size_t size)
 101{
 102    return v9fs_packunpack(dst, out_sg, out_num, offset, size, 0);
 103}
 104
 105ssize_t v9fs_pack(struct iovec *in_sg, int in_num, size_t offset,
 106                  const void *src, size_t size)
 107{
 108    return v9fs_packunpack((void *)src, in_sg, in_num, offset, size, 1);
 109}
 110
 111ssize_t v9fs_unmarshal(struct iovec *out_sg, int out_num, size_t offset,
 112                       int bswap, const char *fmt, ...)
 113{
 114    int i;
 115    va_list ap;
 116    ssize_t copied = 0;
 117    size_t old_offset = offset;
 118
 119    va_start(ap, fmt);
 120    for (i = 0; fmt[i]; i++) {
 121        switch (fmt[i]) {
 122        case 'b': {
 123            uint8_t *valp = va_arg(ap, uint8_t *);
 124            copied = v9fs_unpack(valp, out_sg, out_num, offset, sizeof(*valp));
 125            break;
 126        }
 127        case 'w': {
 128            uint16_t val, *valp;
 129            valp = va_arg(ap, uint16_t *);
 130            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 131            if (bswap) {
 132                *valp = le16_to_cpu(val);
 133            } else {
 134                *valp = val;
 135            }
 136            break;
 137        }
 138        case 'd': {
 139            uint32_t val, *valp;
 140            valp = va_arg(ap, uint32_t *);
 141            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 142            if (bswap) {
 143                *valp = le32_to_cpu(val);
 144            } else {
 145                *valp = val;
 146            }
 147            break;
 148        }
 149        case 'q': {
 150            uint64_t val, *valp;
 151            valp = va_arg(ap, uint64_t *);
 152            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 153            if (bswap) {
 154                *valp = le64_to_cpu(val);
 155            } else {
 156                *valp = val;
 157            }
 158            break;
 159        }
 160        case 's': {
 161            V9fsString *str = va_arg(ap, V9fsString *);
 162            copied = v9fs_unmarshal(out_sg, out_num, offset, bswap,
 163                                    "w", &str->size);
 164            if (copied > 0) {
 165                offset += copied;
 166                str->data = g_malloc(str->size + 1);
 167                copied = v9fs_unpack(str->data, out_sg, out_num, offset,
 168                                     str->size);
 169                if (copied > 0) {
 170                    str->data[str->size] = 0;
 171                } else {
 172                    v9fs_string_free(str);
 173                }
 174            }
 175            break;
 176        }
 177        case 'Q': {
 178            V9fsQID *qidp = va_arg(ap, V9fsQID *);
 179            copied = v9fs_unmarshal(out_sg, out_num, offset, bswap, "bdq",
 180                                    &qidp->type, &qidp->version, &qidp->path);
 181            break;
 182        }
 183        case 'S': {
 184            V9fsStat *statp = va_arg(ap, V9fsStat *);
 185            copied = v9fs_unmarshal(out_sg, out_num, offset, bswap,
 186                                    "wwdQdddqsssssddd",
 187                                    &statp->size, &statp->type, &statp->dev,
 188                                    &statp->qid, &statp->mode, &statp->atime,
 189                                    &statp->mtime, &statp->length,
 190                                    &statp->name, &statp->uid, &statp->gid,
 191                                    &statp->muid, &statp->extension,
 192                                    &statp->n_uid, &statp->n_gid,
 193                                    &statp->n_muid);
 194            break;
 195        }
 196        case 'I': {
 197            V9fsIattr *iattr = va_arg(ap, V9fsIattr *);
 198            copied = v9fs_unmarshal(out_sg, out_num, offset, bswap,
 199                                    "ddddqqqqq",
 200                                    &iattr->valid, &iattr->mode,
 201                                    &iattr->uid, &iattr->gid, &iattr->size,
 202                                    &iattr->atime_sec, &iattr->atime_nsec,
 203                                    &iattr->mtime_sec, &iattr->mtime_nsec);
 204            break;
 205        }
 206        default:
 207            break;
 208        }
 209        if (copied < 0) {
 210            va_end(ap);
 211            return copied;
 212        }
 213        offset += copied;
 214    }
 215    va_end(ap);
 216
 217    return offset - old_offset;
 218}
 219
 220ssize_t v9fs_marshal(struct iovec *in_sg, int in_num, size_t offset,
 221                     int bswap, const char *fmt, ...)
 222{
 223    int i;
 224    va_list ap;
 225    ssize_t copied = 0;
 226    size_t old_offset = offset;
 227
 228    va_start(ap, fmt);
 229    for (i = 0; fmt[i]; i++) {
 230        switch (fmt[i]) {
 231        case 'b': {
 232            uint8_t val = va_arg(ap, int);
 233            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 234            break;
 235        }
 236        case 'w': {
 237            uint16_t val;
 238            if (bswap) {
 239                cpu_to_le16w(&val, va_arg(ap, int));
 240            } else {
 241                val =  va_arg(ap, int);
 242            }
 243            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 244            break;
 245        }
 246        case 'd': {
 247            uint32_t val;
 248            if (bswap) {
 249                cpu_to_le32w(&val, va_arg(ap, uint32_t));
 250            } else {
 251                val =  va_arg(ap, uint32_t);
 252            }
 253            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 254            break;
 255        }
 256        case 'q': {
 257            uint64_t val;
 258            if (bswap) {
 259                cpu_to_le64w(&val, va_arg(ap, uint64_t));
 260            } else {
 261                val =  va_arg(ap, uint64_t);
 262            }
 263            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 264            break;
 265        }
 266        case 's': {
 267            V9fsString *str = va_arg(ap, V9fsString *);
 268            copied = v9fs_marshal(in_sg, in_num, offset, bswap,
 269                                  "w", str->size);
 270            if (copied > 0) {
 271                offset += copied;
 272                copied = v9fs_pack(in_sg, in_num, offset, str->data, str->size);
 273            }
 274            break;
 275        }
 276        case 'Q': {
 277            V9fsQID *qidp = va_arg(ap, V9fsQID *);
 278            copied = v9fs_marshal(in_sg, in_num, offset, bswap, "bdq",
 279                                  qidp->type, qidp->version, qidp->path);
 280            break;
 281        }
 282        case 'S': {
 283            V9fsStat *statp = va_arg(ap, V9fsStat *);
 284            copied = v9fs_marshal(in_sg, in_num, offset, bswap,
 285                                  "wwdQdddqsssssddd",
 286                                  statp->size, statp->type, statp->dev,
 287                                  &statp->qid, statp->mode, statp->atime,
 288                                  statp->mtime, statp->length, &statp->name,
 289                                  &statp->uid, &statp->gid, &statp->muid,
 290                                  &statp->extension, statp->n_uid,
 291                                  statp->n_gid, statp->n_muid);
 292            break;
 293        }
 294        case 'A': {
 295            V9fsStatDotl *statp = va_arg(ap, V9fsStatDotl *);
 296            copied = v9fs_marshal(in_sg, in_num, offset, bswap,
 297                                   "qQdddqqqqqqqqqqqqqqq",
 298                                   statp->st_result_mask,
 299                                   &statp->qid, statp->st_mode,
 300                                   statp->st_uid, statp->st_gid,
 301                                   statp->st_nlink, statp->st_rdev,
 302                                   statp->st_size, statp->st_blksize,
 303                                   statp->st_blocks, statp->st_atime_sec,
 304                                   statp->st_atime_nsec, statp->st_mtime_sec,
 305                                   statp->st_mtime_nsec, statp->st_ctime_sec,
 306                                   statp->st_ctime_nsec, statp->st_btime_sec,
 307                                   statp->st_btime_nsec, statp->st_gen,
 308                                   statp->st_data_version);
 309            break;
 310        }
 311        default:
 312            break;
 313        }
 314        if (copied < 0) {
 315            va_end(ap);
 316            return copied;
 317        }
 318        offset += copied;
 319    }
 320    va_end(ap);
 321
 322    return offset - old_offset;
 323}
 324