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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2013 Lennart Poettering
   4 ***/
   5
   6 #include <errno.h>
   7 #include <string.h>
   8
   9 #include "sd-bus.h"
  10
  11 #include "bus-gvariant.h"
  12 #include "bus-signature.h"
  13 #include "bus-type.h"
  14
  15 int bus_gvariant_get_size(const char *signature) {
  16         const char *p;
  17         int sum = 0, r;
  18
  19         /* For fixed size structs. Fails for variable size structs. */
  20
  21         p = signature;
  22         while (*p != 0) {
  23                 size_t n;
  24
  25                 r = signature_element_length(p, &n);
  26                 if (r < 0)
  27                         return r;
  28                 else {
  29                         char t[n+1];
  30
  31                         memcpy(t, p, n);
  32                         t[n] = 0;
  33
  34                         r = bus_gvariant_get_alignment(t);
  35                         if (r < 0)
  36                                 return r;
  37
  38                         sum = ALIGN_TO(sum, r);
  39                 }
  40
  41                 switch (*p) {
  42
  43                 case SD_BUS_TYPE_BOOLEAN:
  44                 case SD_BUS_TYPE_BYTE:
  45                         sum += 1;
  46                         break;
  47
  48                 case SD_BUS_TYPE_INT16:
  49                 case SD_BUS_TYPE_UINT16:
  50                         sum += 2;
  51                         break;
  52
  53                 case SD_BUS_TYPE_INT32:
  54                 case SD_BUS_TYPE_UINT32:
  55                 case SD_BUS_TYPE_UNIX_FD:
  56                         sum += 4;
  57                         break;
  58
  59                 case SD_BUS_TYPE_INT64:
  60                 case SD_BUS_TYPE_UINT64:
  61                 case SD_BUS_TYPE_DOUBLE:
  62                         sum += 8;
  63                         break;
  64
  65                 case SD_BUS_TYPE_STRUCT_BEGIN:
  66                 case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
  67                         if (n == 2) {
  68                                 /* unary type () has fixed size of 1 */
  69                                 r = 1;
  70                         } else {
  71                                 char t[n-1];
  72
  73                                 memcpy(t, p + 1, n - 2);
  74                                 t[n - 2] = 0;
  75
  76                                 r = bus_gvariant_get_size(t);
  77                                 if (r < 0)
  78                                         return r;
  79                         }
  80
  81                         sum += r;
  82                         break;
  83                 }
  84
  85                 case SD_BUS_TYPE_STRING:
  86                 case SD_BUS_TYPE_OBJECT_PATH:
  87                 case SD_BUS_TYPE_SIGNATURE:
  88                 case SD_BUS_TYPE_ARRAY:
  89                 case SD_BUS_TYPE_VARIANT:
  90                         return -EINVAL;
  91
  92                 default:
  93                         assert_not_reached("Unknown signature type");
  94                 }
  95
  96                 p += n;
  97         }
  98
  99         r = bus_gvariant_get_alignment(signature);
 100         if (r < 0)
 101                 return r;
 102
 103         return ALIGN_TO(sum, r);
 104 }
 105
 106 int bus_gvariant_get_alignment(const char *signature) {
 107         size_t alignment = 1;
 108         const char *p;
 109         int r;
 110
 111         p = signature;
 112         while (*p != 0 && alignment < 8) {
 113                 size_t n;
 114                 int a;
 115
 116                 r = signature_element_length(p, &n);
 117                 if (r < 0)
 118                         return r;
 119
 120                 switch (*p) {
 121
 122                 case SD_BUS_TYPE_BYTE:
 123                 case SD_BUS_TYPE_BOOLEAN:
 124                 case SD_BUS_TYPE_STRING:
 125                 case SD_BUS_TYPE_OBJECT_PATH:
 126                 case SD_BUS_TYPE_SIGNATURE:
 127                         a = 1;
 128                         break;
 129
 130                 case SD_BUS_TYPE_INT16:
 131                 case SD_BUS_TYPE_UINT16:
 132                         a = 2;
 133                         break;
 134
 135                 case SD_BUS_TYPE_INT32:
 136                 case SD_BUS_TYPE_UINT32:
 137                 case SD_BUS_TYPE_UNIX_FD:
 138                         a = 4;
 139                         break;
 140
 141                 case SD_BUS_TYPE_INT64:
 142                 case SD_BUS_TYPE_UINT64:
 143                 case SD_BUS_TYPE_DOUBLE:
 144                 case SD_BUS_TYPE_VARIANT:
 145                         a = 8;
 146                         break;
 147
 148                 case SD_BUS_TYPE_ARRAY: {
 149                         char t[n];
 150
 151                         memcpy(t, p + 1, n - 1);
 152                         t[n - 1] = 0;
 153
 154                         a = bus_gvariant_get_alignment(t);
 155                         break;
 156                 }
 157
 158                 case SD_BUS_TYPE_STRUCT_BEGIN:
 159                 case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
 160                         char t[n-1];
 161
 162                         memcpy(t, p + 1, n - 2);
 163                         t[n - 2] = 0;
 164
 165                         a = bus_gvariant_get_alignment(t);
 166                         break;
 167                 }
 168
 169                 default:
 170                         assert_not_reached("Unknown signature type");
 171                 }
 172
 173                 if (a < 0)
 174                         return a;
 175
 176                 assert(a > 0 && a <= 8);
 177                 if ((size_t) a > alignment)
 178                         alignment = (size_t) a;
 179
 180                 p += n;
 181         }
 182
 183         return alignment;
 184 }
 185
 186 int bus_gvariant_is_fixed_size(const char *signature) {
 187         const char *p;
 188         int r;
 189
 190         assert(signature);
 191
 192         p = signature;
 193         while (*p != 0) {
 194                 size_t n;
 195
 196                 r = signature_element_length(p, &n);
 197                 if (r < 0)
 198                         return r;
 199
 200                 switch (*p) {
 201
 202                 case SD_BUS_TYPE_STRING:
 203                 case SD_BUS_TYPE_OBJECT_PATH:
 204                 case SD_BUS_TYPE_SIGNATURE:
 205                 case SD_BUS_TYPE_ARRAY:
 206                 case SD_BUS_TYPE_VARIANT:
 207                         return 0;
 208
 209                 case SD_BUS_TYPE_BYTE:
 210                 case SD_BUS_TYPE_BOOLEAN:
 211                 case SD_BUS_TYPE_INT16:
 212                 case SD_BUS_TYPE_UINT16:
 213                 case SD_BUS_TYPE_INT32:
 214                 case SD_BUS_TYPE_UINT32:
 215                 case SD_BUS_TYPE_UNIX_FD:
 216                 case SD_BUS_TYPE_INT64:
 217                 case SD_BUS_TYPE_UINT64:
 218                 case SD_BUS_TYPE_DOUBLE:
 219                         break;
 220
 221                 case SD_BUS_TYPE_STRUCT_BEGIN:
 222                 case SD_BUS_TYPE_DICT_ENTRY_BEGIN: {
 223                         char t[n-1];
 224
 225                         memcpy(t, p + 1, n - 2);
 226                         t[n - 2] = 0;
 227
 228                         r = bus_gvariant_is_fixed_size(t);
 229                         if (r <= 0)
 230                                 return r;
 231                         break;
 232                 }
 233
 234                 default:
 235                         assert_not_reached("Unknown signature type");
 236                 }
 237
 238                 p += n;
 239         }
 240
 241         return true;
 242 }
 243
 244 size_t bus_gvariant_determine_word_size(size_t sz, size_t extra) {
 245         if (sz + extra <= 0xFF)
 246                 return 1;
 247         else if (sz + extra*2 <= 0xFFFF)
 248                 return 2;
 249         else if (sz + extra*4 <= 0xFFFFFFFF)
 250                 return 4;
 251         else
 252                 return 8;
 253 }
 254
 255 size_t bus_gvariant_read_word_le(void *p, size_t sz) {
 256         union {
 257                 uint16_t u16;
 258                 uint32_t u32;
 259                 uint64_t u64;
 260         } x;
 261
 262         assert(p);
 263
 264         if (sz == 1)
 265                 return *(uint8_t*) p;
 266
 267         memcpy(&x, p, sz);
 268
 269         if (sz == 2)
 270                 return le16toh(x.u16);
 271         else if (sz == 4)
 272                 return le32toh(x.u32);
 273         else if (sz == 8)
 274                 return le64toh(x.u64);
 275
 276         assert_not_reached("unknown word width");
 277 }
 278
 279 void bus_gvariant_write_word_le(void *p, size_t sz, size_t value) {
 280         union {
 281                 uint16_t u16;
 282                 uint32_t u32;
 283                 uint64_t u64;
 284         } x;
 285
 286         assert(p);
 287         assert(sz == 8 || (value < (1ULL << (sz*8))));
 288
 289         if (sz == 1) {
 290                 *(uint8_t*) p = value;
 291                 return;
 292         } else if (sz == 2)
 293                 x.u16 = htole16((uint16_t) value);
 294         else if (sz == 4)
 295                 x.u32 = htole32((uint32_t) value);
 296         else if (sz == 8)
 297                 x.u64 = htole64((uint64_t) value);
 298         else
 299                 assert_not_reached("unknown word width");
 300
 301         memcpy(p, &x, sz);
 302 }