src/src/lookups/json.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) Jeremy Harris 2019 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8 #include "../exim.h"
   9 #include "lf_functions.h"
  10 #include <jansson.h>
  11
  12
  13
  14 /* All use of allocations will be done against the POOL_SEARCH memory,
  15 which is freed once by search_tidyup(). Make the free call a dummy.
  16 This burns some 300kB in handling a 37kB JSON file, for the benefit of
  17 a fast free.  The alternative of staying with malloc is nearly as bad,
  18 eyeballing the activity there are 20% the number of free vs. alloc
  19 calls (before the big bunch at the end). */
  20
  21 static void *
  22 json_malloc(size_t nbytes)
  23 {
  24 void * p = store_get((int)nbytes);
  25 /* debug_printf("%s %d: %p\n", __FUNCTION__, (int)nbytes, p); */
  26 return p;
  27 }
  28 static void
  29 json_free(void * p)
  30 {
  31 /* debug_printf("%s: %p\n", __FUNCTION__, p); */
  32 }
  33
  34 /*************************************************
  35 *              Open entry point                  *
  36 *************************************************/
  37
  38 /* See local README for interface description */
  39
  40 static void *
  41 json_open(uschar *filename, uschar **errmsg)
  42 {
  43 FILE * f;
  44
  45 json_set_alloc_funcs(json_malloc, json_free);
  46
  47 if (!(f = Ufopen(filename, "rb")))
  48   {
  49   int save_errno = errno;
  50   *errmsg = string_open_failed(errno, "%s for json search", filename);
  51   errno = save_errno;
  52   return NULL;
  53   }
  54 return f;
  55 }
  56
  57
  58
  59 /*************************************************
  60 *             Check entry point                  *
  61 *************************************************/
  62
  63 static BOOL
  64 json_check(void *handle, uschar *filename, int modemask, uid_t *owners,
  65   gid_t *owngroups, uschar **errmsg)
  66 {
  67 return lf_check_file(fileno((FILE *)handle), filename, S_IFREG, modemask,
  68   owners, owngroups, "json", errmsg) == 0;
  69 }
  70
  71
  72
  73 /*************************************************
  74 *         Find entry point for lsearch           *
  75 *************************************************/
  76
  77 /* See local README for interface description */
  78
  79 static int
  80 json_find(void *handle, uschar *filename, const uschar *keystring, int length,
  81   uschar **result, uschar **errmsg, uint *do_cache)
  82 {
  83 FILE * f = handle;
  84 json_t * j, * j0;
  85 json_error_t jerr;
  86 uschar * key;
  87 int sep = 0;
  88
  89 length = length;        /* Keep picky compilers happy */
  90 do_cache = do_cache;    /* Keep picky compilers happy */
  91
  92 rewind(f);
  93 if (!(j = json_loadf(f, 0, &jerr)))
  94   {
  95   *errmsg = string_sprintf("json error on open: %.*s\n",
  96        JSON_ERROR_TEXT_LENGTH, jerr.text);
  97   return FAIL;
  98   }
  99 j0 = j;
 100
 101 for (int k = 1;  (key = string_nextinlist(&keystring, &sep, NULL, 0)); k++)
 102   {
 103   BOOL numeric = TRUE;
 104   for (uschar * s = key; *s; s++) if (!isdigit(*s)) { numeric = FALSE; break; }
 105
 106   if (!(j = numeric
 107         ? json_array_get(j, (size_t) strtoul(CS key, NULL, 10))
 108         : json_object_get(j, CCS key)
 109      ) )
 110     {
 111     DEBUG(D_lookup) debug_printf("%s, for key %d: '%s'\n",
 112       numeric
 113       ? US"bad index, or not json array"
 114       : US"no such key, or not json object",
 115       k, key);
 116     json_decref(j0);
 117     return FAIL;
 118     }
 119   }
 120
 121 switch (json_typeof(j))
 122   {
 123   case JSON_STRING:
 124     *result = string_copyn(CUS json_string_value(j), json_string_length(j));
 125     break;
 126   case JSON_INTEGER:
 127     *result = string_sprintf("%" JSON_INTEGER_FORMAT, json_integer_value(j));
 128     break;
 129   case JSON_REAL:
 130     *result = string_sprintf("%f", json_real_value(j));
 131     break;
 132   case JSON_TRUE:       *result = US"true";     break;
 133   case JSON_FALSE:      *result = US"false";    break;
 134   case JSON_NULL:       *result = NULL;         break;
 135   default:              *result = US json_dumps(j, 0); break;
 136   }
 137 json_decref(j0);
 138 return OK;
 139 }
 140
 141
 142
 143 /*************************************************
 144 *              Close entry point                 *
 145 *************************************************/
 146
 147 /* See local README for interface description */
 148
 149 static void
 150 json_close(void *handle)
 151 {
 152 (void)fclose((FILE *)handle);
 153 }
 154
 155
 156
 157 /*************************************************
 158 *         Version reporting entry point          *
 159 *************************************************/
 160
 161 /* See local README for interface description. */
 162
 163 #include "../version.h"
 164
 165 void
 166 json_version_report(FILE *f)
 167 {
 168 fprintf(f, "Library version: json: Jansonn version %s\n", JANSSON_VERSION);
 169 }
 170
 171
 172 static lookup_info json_lookup_info = {
 173   US"json",                      /* lookup name */
 174   lookup_absfile,                /* uses absolute file name */
 175   json_open,                  /* open function */
 176   json_check,                 /* check function */
 177   json_find,                  /* find function */
 178   json_close,                 /* close function */
 179   NULL,                          /* no tidy function */
 180   NULL,                          /* no quoting function */
 181   json_version_report         /* version reporting */
 182 };
 183
 184
 185 #ifdef DYNLOOKUP
 186 #define json_lookup_module_info _lookup_module_info
 187 #endif
 188
 189 static lookup_info *_lookup_list[] = { &json_lookup_info };
 190 lookup_module_info json_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
 191
 192 /* End of lookups/json.c */