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.h>
  16#include <glib/gprintf.h>
  17#include <utime.h>
  18#include <sys/uio.h>
  19
  20#include "9p-iov-marshal.h"
  21#include "qemu/bswap.h"
  22
  23static ssize_t v9fs_packunpack(void *addr, struct iovec *sg, int sg_count,
  24                               size_t offset, size_t size, int pack)
  25{
  26    int i = 0;
  27    size_t copied = 0;
  28    size_t req_size = size;
  29
  30
  31    for (i = 0; size && i < sg_count; i++) {
  32        size_t len;
  33        if (offset >= sg[i].iov_len) {
  34            /* skip this sg */
  35            offset -= sg[i].iov_len;
  36            continue;
  37        } else {
  38            len = MIN(sg[i].iov_len - offset, size);
  39            if (pack) {
  40                memcpy(sg[i].iov_base + offset, addr, len);
  41            } else {
  42                memcpy(addr, sg[i].iov_base + offset, len);
  43            }
  44            size -= len;
  45            copied += len;
  46            addr += len;
  47            if (size) {
  48                offset = 0;
  49                continue;
  50            }
  51        }
  52    }
  53    if (copied < req_size) {
  54        /*
  55         * We copied less that requested size. error out
  56         */
  57        return -ENOBUFS;
  58    }
  59    return copied;
  60}
  61
  62static ssize_t v9fs_unpack(void *dst, struct iovec *out_sg, int out_num,
  63                           size_t offset, size_t size)
  64{
  65    return v9fs_packunpack(dst, out_sg, out_num, offset, size, 0);
  66}
  67
  68ssize_t v9fs_pack(struct iovec *in_sg, int in_num, size_t offset,
  69                  const void *src, size_t size)
  70{
  71    return v9fs_packunpack((void *)src, in_sg, in_num, offset, size, 1);
  72}
  73
  74ssize_t v9fs_iov_vunmarshal(struct iovec *out_sg, int out_num, size_t offset,
  75                            int bswap, const char *fmt, va_list ap)
  76{
  77    int i;
  78    ssize_t copied = 0;
  79    size_t old_offset = offset;
  80
  81    for (i = 0; fmt[i]; i++) {
  82        switch (fmt[i]) {
  83        case 'b': {
  84            uint8_t *valp = va_arg(ap, uint8_t *);
  85            copied = v9fs_unpack(valp, out_sg, out_num, offset, sizeof(*valp));
  86            break;
  87        }
  88        case 'w': {
  89            uint16_t val, *valp;
  90            valp = va_arg(ap, uint16_t *);
  91            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
  92            if (bswap) {
  93                *valp = le16_to_cpu(val);
  94            } else {
  95                *valp = val;
  96            }
  97            break;
  98        }
  99        case 'd': {
 100            uint32_t val, *valp;
 101            valp = va_arg(ap, uint32_t *);
 102            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 103            if (bswap) {
 104                *valp = le32_to_cpu(val);
 105            } else {
 106                *valp = val;
 107            }
 108            break;
 109        }
 110        case 'q': {
 111            uint64_t val, *valp;
 112            valp = va_arg(ap, uint64_t *);
 113            copied = v9fs_unpack(&val, out_sg, out_num, offset, sizeof(val));
 114            if (bswap) {
 115                *valp = le64_to_cpu(val);
 116            } else {
 117                *valp = val;
 118            }
 119            break;
 120        }
 121        case 's': {
 122            V9fsString *str = va_arg(ap, V9fsString *);
 123            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 124                                        "w", &str->size);
 125            if (copied > 0) {
 126                offset += copied;
 127                str->data = g_malloc(str->size + 1);
 128                copied = v9fs_unpack(str->data, out_sg, out_num, offset,
 129                                     str->size);
 130                if (copied > 0) {
 131                    str->data[str->size] = 0;
 132                } else {
 133                    v9fs_string_free(str);
 134                }
 135            }
 136            break;
 137        }
 138        case 'Q': {
 139            V9fsQID *qidp = va_arg(ap, V9fsQID *);
 140            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 141                                        "bdq", &qidp->type, &qidp->version,
 142                                        &qidp->path);
 143            break;
 144        }
 145        case 'S': {
 146            V9fsStat *statp = va_arg(ap, V9fsStat *);
 147            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 148                                        "wwdQdddqsssssddd",
 149                                        &statp->size, &statp->type,
 150                                        &statp->dev, &statp->qid,
 151                                        &statp->mode, &statp->atime,
 152                                        &statp->mtime, &statp->length,
 153                                        &statp->name, &statp->uid,
 154                                        &statp->gid, &statp->muid,
 155                                        &statp->extension,
 156                                        &statp->n_uid, &statp->n_gid,
 157                                        &statp->n_muid);
 158            break;
 159        }
 160        case 'I': {
 161            V9fsIattr *iattr = va_arg(ap, V9fsIattr *);
 162            copied = v9fs_iov_unmarshal(out_sg, out_num, offset, bswap,
 163                                        "ddddqqqqq",
 164                                        &iattr->valid, &iattr->mode,
 165                                        &iattr->uid, &iattr->gid,
 166                                        &iattr->size, &iattr->atime_sec,
 167                                        &iattr->atime_nsec,
 168                                        &iattr->mtime_sec,
 169                                        &iattr->mtime_nsec);
 170            break;
 171        }
 172        default:
 173            break;
 174        }
 175        if (copied < 0) {
 176            return copied;
 177        }
 178        offset += copied;
 179    }
 180
 181    return offset - old_offset;
 182}
 183
 184ssize_t v9fs_iov_unmarshal(struct iovec *out_sg, int out_num, size_t offset,
 185                           int bswap, const char *fmt, ...)
 186{
 187    ssize_t ret;
 188    va_list ap;
 189
 190    va_start(ap, fmt);
 191    ret = v9fs_iov_vunmarshal(out_sg, out_num, offset, bswap, fmt, ap);
 192    va_end(ap);
 193
 194    return ret;
 195}
 196
 197ssize_t v9fs_iov_vmarshal(struct iovec *in_sg, int in_num, size_t offset,
 198                          int bswap, const char *fmt, va_list ap)
 199{
 200    int i;
 201    ssize_t copied = 0;
 202    size_t old_offset = offset;
 203
 204    for (i = 0; fmt[i]; i++) {
 205        switch (fmt[i]) {
 206        case 'b': {
 207            uint8_t val = va_arg(ap, int);
 208            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 209            break;
 210        }
 211        case 'w': {
 212            uint16_t val;
 213            if (bswap) {
 214                cpu_to_le16w(&val, va_arg(ap, int));
 215            } else {
 216                val =  va_arg(ap, int);
 217            }
 218            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 219            break;
 220        }
 221        case 'd': {
 222            uint32_t val;
 223            if (bswap) {
 224                cpu_to_le32w(&val, va_arg(ap, uint32_t));
 225            } else {
 226                val =  va_arg(ap, uint32_t);
 227            }
 228            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 229            break;
 230        }
 231        case 'q': {
 232            uint64_t val;
 233            if (bswap) {
 234                cpu_to_le64w(&val, va_arg(ap, uint64_t));
 235            } else {
 236                val =  va_arg(ap, uint64_t);
 237            }
 238            copied = v9fs_pack(in_sg, in_num, offset, &val, sizeof(val));
 239            break;
 240        }
 241        case 's': {
 242            V9fsString *str = va_arg(ap, V9fsString *);
 243            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap,
 244                                      "w", str->size);
 245            if (copied > 0) {
 246                offset += copied;
 247                copied = v9fs_pack(in_sg, in_num, offset, str->data, str->size);
 248            }
 249            break;
 250        }
 251        case 'Q': {
 252            V9fsQID *qidp = va_arg(ap, V9fsQID *);
 253            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap, "bdq",
 254                                      qidp->type, qidp->version,
 255                                      qidp->path);
 256            break;
 257        }
 258        case 'S': {
 259            V9fsStat *statp = va_arg(ap, V9fsStat *);
 260            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap,
 261                                      "wwdQdddqsssssddd",
 262                                      statp->size, statp->type, statp->dev,
 263                                      &statp->qid, statp->mode, statp->atime,
 264                                      statp->mtime, statp->length,
 265                                      &statp->name,
 266                                      &statp->uid, &statp->gid, &statp->muid,
 267                                      &statp->extension, statp->n_uid,
 268                                      statp->n_gid, statp->n_muid);
 269            break;
 270        }
 271        case 'A': {
 272            V9fsStatDotl *statp = va_arg(ap, V9fsStatDotl *);
 273            copied = v9fs_iov_marshal(in_sg, in_num, offset, bswap,
 274                                      "qQdddqqqqqqqqqqqqqqq",
 275                                      statp->st_result_mask,
 276                                      &statp->qid, statp->st_mode,
 277                                      statp->st_uid, statp->st_gid,
 278                                      statp->st_nlink, statp->st_rdev,
 279                                      statp->st_size, statp->st_blksize,
 280                                      statp->st_blocks, statp->st_atime_sec,
 281                                      statp->st_atime_nsec,
 282                                      statp->st_mtime_sec,
 283                                      statp->st_mtime_nsec,
 284                                      statp->st_ctime_sec,
 285                                      statp->st_ctime_nsec,
 286                                      statp->st_btime_sec,
 287                                      statp->st_btime_nsec, statp->st_gen,
 288                                      statp->st_data_version);
 289            break;
 290        }
 291        default:
 292            break;
 293        }
 294        if (copied < 0) {
 295            return copied;
 296        }
 297        offset += copied;
 298    }
 299
 300    return offset - old_offset;
 301}
 302
 303ssize_t v9fs_iov_marshal(struct iovec *in_sg, int in_num, size_t offset,
 304                         int bswap, const char *fmt, ...)
 305{
 306    ssize_t ret;
 307    va_list ap;
 308
 309    va_start(ap, fmt);
 310    ret = v9fs_iov_vmarshal(in_sg, in_num, offset, bswap, fmt, ap);
 311    va_end(ap);
 312
 313    return ret;
 314}
 315