src/libelogind/sd-bus/bus-gvariant.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2013 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include "bus-gvariant.h"
  21 #include "bus-signature.h"
  22 #include "bus-type.h"
  23
  24 int bus_gvariant_get_size(const char *signature) {
  25         const char *p;
  26         int sum = 0, r;
  27
  28         /* For fixed size structs. Fails for variable size structs. */
  29
  30         p = signature;
  31         while (*p != 0) {
  32                 size_t n;
  33
  34                 r = signature_element_length(p, &n);
  35                 if (r < 0)
  36                         return r;
  37                 else {
  38                         char t[n+1];
  39
  40                         memcpy(t, p, n);
  41                         t[n] = 0;
  42
  43                         r = bus_gvariant_get_alignment(t);
  44                         if (r < 0)
  45                                 return r;
  46
  47                         sum = ALIGN_TO(sum, r);
  48                 }
  49
  50                 switch (*p) {
  51
  52                 case SD_BUS_TYPE_BOOLEAN:
  53                 case SD_BUS_TYPE_BYTE:
  54                         sum += 1;
  55                         break;
  56
  57                 case SD_BUS_TYPE_INT16:
  58                 case SD_BUS_TYPE_UINT16:
  59                         sum += 2;
  60                         break;
  61
  62                 case SD_BUS_TYPE_INT32:
  63                 case SD_BUS_TYPE_UINT32:
  64                 case SD_BUS_TYPE_UNIX_FD:
  65                         sum += 4;
  66                         break;
  67
  68                 case SD_BUS_TYPE_INT64:
  69                 case SD_BUS_TYPE_UINT64:
  70                 case SD_BUS_TYPE_DOUBLE:
  71                         sum += 8;
  72                         break;
  73
  74                 case SD_BUS_TYPE_STRUCT_BEGIN:
  75                 case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
  76                         if (n == 2) {
  77                                 /* unary type () has fixed size of 1 */
  78                                 r = 1;
  79                         } else {
  80                                 char t[n-1];
  81
  82                                 memcpy(t, p + 1, n - 2);
  83                                 t[n - 2] = 0;
  84
  85                                 r = bus_gvariant_get_size(t);
  86                                 if (r < 0)
  87                                         return r;
  88                         }
  89
  90                         sum += r;
  91                         break;
  92                 }
  93
  94                 case SD_BUS_TYPE_STRING:
  95                 case SD_BUS_TYPE_OBJECT_PATH:
  96                 case SD_BUS_TYPE_SIGNATURE:
  97                 case SD_BUS_TYPE_ARRAY:
  98                 case SD_BUS_TYPE_VARIANT:
  99                         return -EINVAL;
 100
 101                 default:
 102                         assert_not_reached("Unknown signature type");
 103                 }
 104
 105                 p += n;
 106         }
 107
 108         r = bus_gvariant_get_alignment(signature);
 109         if (r < 0)
 110                 return r;
 111
 112         return ALIGN_TO(sum, r);
 113 }
 114
 115 int bus_gvariant_get_alignment(const char *signature) {
 116         size_t alignment = 1;
 117         const char *p;
 118         int r;
 119
 120         p = signature;
 121         while (*p != 0 && alignment < 8) {
 122                 size_t n;
 123                 int a;
 124
 125                 r = signature_element_length(p, &n);
 126                 if (r < 0)
 127                         return r;
 128
 129                 switch (*p) {
 130
 131                 case SD_BUS_TYPE_BYTE:
 132                 case SD_BUS_TYPE_BOOLEAN:
 133                 case SD_BUS_TYPE_STRING:
 134                 case SD_BUS_TYPE_OBJECT_PATH:
 135                 case SD_BUS_TYPE_SIGNATURE:
 136                         a = 1;
 137                         break;
 138
 139                 case SD_BUS_TYPE_INT16:
 140                 case SD_BUS_TYPE_UINT16:
 141                         a = 2;
 142                         break;
 143
 144                 case SD_BUS_TYPE_INT32:
 145                 case SD_BUS_TYPE_UINT32:
 146                 case SD_BUS_TYPE_UNIX_FD:
 147                         a = 4;
 148                         break;
 149
 150                 case SD_BUS_TYPE_INT64:
 151                 case SD_BUS_TYPE_UINT64:
 152                 case SD_BUS_TYPE_DOUBLE:
 153                 case SD_BUS_TYPE_VARIANT:
 154                         a = 8;
 155                         break;
 156
 157                 case SD_BUS_TYPE_ARRAY: {
 158                         char t[n];
 159
 160                         memcpy(t, p + 1, n - 1);
 161                         t[n - 1] = 0;
 162
 163                         a = bus_gvariant_get_alignment(t);
 164                         break;
 165                 }
 166
 167                 case SD_BUS_TYPE_STRUCT_BEGIN:
 168                 case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
 169                         char t[n-1];
 170
 171                         memcpy(t, p + 1, n - 2);
 172                         t[n - 2] = 0;
 173
 174                         a = bus_gvariant_get_alignment(t);
 175                         break;
 176                 }
 177
 178                 default:
 179                         assert_not_reached("Unknown signature type");
 180                 }
 181
 182                 if (a < 0)
 183                         return a;
 184
 185                 assert(a > 0 && a <= 8);
 186                 if ((size_t) a > alignment)
 187                         alignment = (size_t) a;
 188
 189                 p += n;
 190         }
 191
 192         return alignment;
 193 }
 194
 195 int bus_gvariant_is_fixed_size(const char *signature) {
 196         const char *p;
 197         int r;
 198
 199         assert(signature);
 200
 201         p = signature;
 202         while (*p != 0) {
 203                 size_t n;
 204
 205                 r = signature_element_length(p, &n);
 206                 if (r < 0)
 207                         return r;
 208
 209                 switch (*p) {
 210
 211                 case SD_BUS_TYPE_STRING:
 212                 case SD_BUS_TYPE_OBJECT_PATH:
 213                 case SD_BUS_TYPE_SIGNATURE:
 214                 case SD_BUS_TYPE_ARRAY:
 215                 case SD_BUS_TYPE_VARIANT:
 216                         return 0;
 217
 218                 case SD_BUS_TYPE_BYTE:
 219                 case SD_BUS_TYPE_BOOLEAN:
 220                 case SD_BUS_TYPE_INT16:
 221                 case SD_BUS_TYPE_UINT16:
 222                 case SD_BUS_TYPE_INT32:
 223                 case SD_BUS_TYPE_UINT32:
 224                 case SD_BUS_TYPE_UNIX_FD:
 225                 case SD_BUS_TYPE_INT64:
 226                 case SD_BUS_TYPE_UINT64:
 227                 case SD_BUS_TYPE_DOUBLE:
 228                         break;
 229
 230                 case SD_BUS_TYPE_STRUCT_BEGIN:
 231                 case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
 232                         char t[n-1];
 233
 234                         memcpy(t, p + 1, n - 2);
 235                         t[n - 2] = 0;
 236
 237                         r = bus_gvariant_is_fixed_size(t);
 238                         if (r <= 0)
 239                                 return r;
 240                         break;
 241                 }
 242
 243                 default:
 244                         assert_not_reached("Unknown signature type");
 245                 }
 246
 247                 p += n;
 248         }
 249
 250         return true;
 251 }
 252
 253 size_t bus_gvariant_determine_word_size(size_t sz, size_t extra) {
 254         if (sz + extra <= 0xFF)
 255                 return 1;
 256         else if (sz + extra*2 <= 0xFFFF)
 257                 return 2;
 258         else if (sz + extra*4 <= 0xFFFFFFFF)
 259                 return 4;
 260         else
 261                 return 8;
 262 }
 263
 264 size_t bus_gvariant_read_word_le(void *p, size_t sz) {
 265         union {
 266                 uint16_t u16;
 267                 uint32_t u32;
 268                 uint64_t u64;
 269         } x;
 270
 271         assert(p);
 272
 273         if (sz == 1)
 274                 return *(uint8_t*) p;
 275
 276         memcpy(&x, p, sz);
 277
 278         if (sz == 2)
 279                 return le16toh(x.u16);
 280         else if (sz == 4)
 281                 return le32toh(x.u32);
 282         else if (sz == 8)
 283                 return le64toh(x.u64);
 284
 285         assert_not_reached("unknown word width");
 286 }
 287
 288 void bus_gvariant_write_word_le(void *p, size_t sz, size_t value) {
 289         union {
 290                 uint16_t u16;
 291                 uint32_t u32;
 292                 uint64_t u64;
 293         } x;
 294
 295         assert(p);
 296         assert(sz == 8 || (value < (1ULL << (sz*8))));
 297
 298         if (sz == 1) {
 299                 *(uint8_t*) p = value;
 300                 return;
 301         } else if (sz == 2)
 302                 x.u16 = htole16((uint16_t) value);
 303         else if (sz == 4)
 304                 x.u32 = htole32((uint32_t) value);
 305         else if (sz == 8)
 306                 x.u64 = htole64((uint64_t) value);
 307         else
 308                 assert_not_reached("unknown word width");
 309
 310         memcpy(p, &x, sz);
 311 }