blobmsg.h

   1 /*
   2  * Copyright (C) 2010-2012 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 #ifndef __BLOBMSG_H
  17 #define __BLOBMSG_H
  18
  19 #include <stdarg.h>
  20 #include "blob.h"
  21
  22 #define BLOBMSG_ALIGN   2
  23 #define BLOBMSG_PADDING(len) (((len) + (1 << BLOBMSG_ALIGN) - 1) & ~((1 << BLOBMSG_ALIGN) - 1))
  24
  25 enum blobmsg_type {
  26         BLOBMSG_TYPE_UNSPEC,
  27         BLOBMSG_TYPE_ARRAY,
  28         BLOBMSG_TYPE_TABLE,
  29         BLOBMSG_TYPE_STRING,
  30         BLOBMSG_TYPE_INT64,
  31         BLOBMSG_TYPE_INT32,
  32         BLOBMSG_TYPE_INT16,
  33         BLOBMSG_TYPE_INT8,
  34         BLOBMSG_TYPE_DOUBLE,
  35         __BLOBMSG_TYPE_LAST,
  36         BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
  37         BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
  38 };
  39
  40 struct blobmsg_hdr {
  41         uint16_t namelen;
  42         uint8_t name[];
  43 } __packed;
  44
  45 struct blobmsg_policy {
  46         const char *name;
  47         enum blobmsg_type type;
  48 };
  49
  50 static inline int blobmsg_hdrlen(unsigned int namelen)
  51 {
  52         return BLOBMSG_PADDING(sizeof(struct blobmsg_hdr) + namelen + 1);
  53 }
  54
  55 static inline void blobmsg_clear_name(struct blob_attr *attr)
  56 {
  57         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  58         hdr->name[0] = 0;
  59 }
  60
  61 static inline const char *blobmsg_name(const struct blob_attr *attr)
  62 {
  63         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  64         return (const char *) hdr->name;
  65 }
  66
  67 static inline int blobmsg_type(const struct blob_attr *attr)
  68 {
  69         return blob_id(attr);
  70 }
  71
  72 static inline void *blobmsg_data(const struct blob_attr *attr)
  73 {
  74         struct blobmsg_hdr *hdr;
  75         char *data;
  76
  77         if (!attr)
  78                 return NULL;
  79
  80         hdr = (struct blobmsg_hdr *) blob_data(attr);
  81         data = (char *) blob_data(attr);
  82
  83         if (blob_is_extended(attr))
  84                 data += blobmsg_hdrlen(be16_to_cpu(hdr->namelen));
  85
  86         return data;
  87 }
  88
  89 static inline size_t blobmsg_data_len(const struct blob_attr *attr)
  90 {
  91         uint8_t *start, *end;
  92
  93         if (!attr)
  94                 return 0;
  95
  96         start = (uint8_t *) blob_data(attr);
  97         end = (uint8_t *) blobmsg_data(attr);
  98
  99         return blob_len(attr) - (end - start);
 100 }
 101
 102 static inline size_t blobmsg_len(const struct blob_attr *attr)
 103 {
 104         return blobmsg_data_len(attr);
 105 }
 106
 107 /*
 108  * blobmsg_check_attr: validate a list of attributes
 109  *
 110  * This method may be used with trusted data only. Providing
 111  * malformed blobs will cause out of bounds memory access.
 112  */
 113 bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
 114
 115 /*
 116  * blobmsg_check_attr_len: validate a list of attributes
 117  *
 118  * This method should be safer implementation of blobmsg_check_attr.
 119  * It will limit all memory access performed on the blob to the
 120  * range [attr, attr + len] (upper bound non inclusive) and is
 121  * thus suited for checking of untrusted blob attributes.
 122  */
 123 bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len);
 124
 125 /*
 126  * blobmsg_check_attr_list: validate a list of attributes
 127  *
 128  * This method may be used with trusted data only. Providing
 129  * malformed blobs will cause out of bounds memory access.
 130  */
 131 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
 132
 133 /*
 134  * blobmsg_check_attr_list_len: validate a list of untrusted attributes
 135  *
 136  * This method should be safer implementation of blobmsg_check_attr_list.
 137  * It will limit all memory access performed on the blob to the
 138  * range [attr, attr + len] (upper bound non inclusive) and is
 139  * thus suited for checking of untrusted blob attributes.
 140  */
 141 bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len);
 142
 143 /*
 144  * blobmsg_check_array: validate array/table and return size
 145  *
 146  * Checks if all elements of an array or table are valid and have
 147  * the specified type. Returns the number of elements in the array
 148  *
 149  * This method may be used with trusted data only. Providing
 150  * malformed blobs will cause out of bounds memory access.
 151  */
 152 int blobmsg_check_array(const struct blob_attr *attr, int type);
 153
 154 /*
 155  * blobmsg_check_array_len: validate untrusted array/table and return size
 156  *
 157  * Checks if all elements of an array or table are valid and have
 158  * the specified type. Returns the number of elements in the array.
 159  *
 160  * This method should be safer implementation of blobmsg_check_array.
 161  * It will limit all memory access performed on the blob to the
 162  * range [attr, attr + len] (upper bound non inclusive) and is
 163  * thus suited for checking of untrusted blob attributes.
 164  */
 165 int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len);
 166
 167 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 168                   struct blob_attr **tb, void *data, unsigned int len);
 169 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 170                         struct blob_attr **tb, void *data, unsigned int len);
 171
 172 int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 173                       const void *data, unsigned int len);
 174
 175 static inline int
 176 blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
 177 {
 178         union {
 179                 double d;
 180                 uint64_t u64;
 181         } v;
 182         v.d = val;
 183         v.u64 = cpu_to_be64(v.u64);
 184         return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
 185 }
 186
 187 static inline int
 188 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
 189 {
 190         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
 191 }
 192
 193 static inline int
 194 blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
 195 {
 196         val = cpu_to_be16(val);
 197         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
 198 }
 199
 200 static inline int
 201 blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
 202 {
 203         val = cpu_to_be32(val);
 204         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
 205 }
 206
 207 static inline int
 208 blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
 209 {
 210         val = cpu_to_be64(val);
 211         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
 212 }
 213
 214 static inline int
 215 blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
 216 {
 217         return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
 218 }
 219
 220 static inline int
 221 blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
 222 {
 223         return blobmsg_add_field(buf, blobmsg_type(attr), blobmsg_name(attr),
 224                                  blobmsg_data(attr), blobmsg_data_len(attr));
 225 }
 226
 227 void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
 228
 229 static inline void *
 230 blobmsg_open_array(struct blob_buf *buf, const char *name)
 231 {
 232         return blobmsg_open_nested(buf, name, true);
 233 }
 234
 235 static inline void *
 236 blobmsg_open_table(struct blob_buf *buf, const char *name)
 237 {
 238         return blobmsg_open_nested(buf, name, false);
 239 }
 240
 241 static inline void
 242 blobmsg_close_array(struct blob_buf *buf, void *cookie)
 243 {
 244         blob_nest_end(buf, cookie);
 245 }
 246
 247 static inline void
 248 blobmsg_close_table(struct blob_buf *buf, void *cookie)
 249 {
 250         blob_nest_end(buf, cookie);
 251 }
 252
 253 static inline int blobmsg_buf_init(struct blob_buf *buf)
 254 {
 255         return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
 256 }
 257
 258 static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
 259 {
 260         return *(uint8_t *) blobmsg_data(attr);
 261 }
 262
 263 static inline bool blobmsg_get_bool(struct blob_attr *attr)
 264 {
 265         return *(uint8_t *) blobmsg_data(attr);
 266 }
 267
 268 static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
 269 {
 270         return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
 271 }
 272
 273 static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
 274 {
 275         return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
 276 }
 277
 278 static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
 279 {
 280         uint32_t *ptr = (uint32_t *) blobmsg_data(attr);
 281         uint64_t tmp = ((uint64_t) be32_to_cpu(ptr[0])) << 32;
 282         tmp |= be32_to_cpu(ptr[1]);
 283         return tmp;
 284 }
 285
 286 static inline double blobmsg_get_double(struct blob_attr *attr)
 287 {
 288         union {
 289                 double d;
 290                 uint64_t u64;
 291         } v;
 292         v.u64 = blobmsg_get_u64(attr);
 293         return v.d;
 294 }
 295
 296 static inline char *blobmsg_get_string(struct blob_attr *attr)
 297 {
 298         if (!attr)
 299                 return NULL;
 300
 301         return (char *) blobmsg_data(attr);
 302 }
 303
 304 void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen);
 305 void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen);
 306 void blobmsg_add_string_buffer(struct blob_buf *buf);
 307
 308 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg);
 309 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 310      __attribute__((format(printf, 3, 4)));
 311
 312
 313 /* blobmsg to json formatting */
 314
 315 #define blobmsg_for_each_attr(pos, attr, rem) \
 316         for (rem = attr ? blobmsg_data_len(attr) : 0, \
 317              pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 318              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 319              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 320              rem -= blob_pad_len(pos), pos = blob_next(pos))
 321
 322 #define __blobmsg_for_each_attr(pos, attr, rem) \
 323         for (pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
 324              rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
 325              (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 326              rem -= blob_pad_len(pos), pos = blob_next(pos))
 327
 328 #endif