JSON lookup

[exim.git] / src / src / lookups / json.c

diff --git a/src/src/lookups/json.c b/src/src/lookups/json.c
new file mode 100644 (file)
index 0000000..0b28b73
--- /dev/null
+++ b/src/src/lookups/json.c
@@ -0,0 +1,192 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) Jeremy Harris 2019 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+#include "../exim.h"
+#include "lf_functions.h"
+#include <jansson.h>
+
+
+
+/* All use of allocations will be done against the POOL_SEARCH memory,
+which is freed once by search_tidyup(). Make the free call a dummy.
+This burns some 300kB in handling a 37kB JSON file, for the benefit of
+a fast free.  The alternative of staying with malloc is nearly as bad,
+eyeballing the activity there are 20% the number of free vs. alloc
+calls (before the big bunch at the end). */
+
+static void *
+json_malloc(size_t nbytes)
+{
+void * p = store_get((int)nbytes);
+/* debug_printf("%s %d: %p\n", __FUNCTION__, (int)nbytes, p); */
+return p;
+}
+static void
+json_free(void * p)
+{
+/* debug_printf("%s: %p\n", __FUNCTION__, p); */
+}
+
+/*************************************************
+*              Open entry point                  *
+*************************************************/
+
+/* See local README for interface description */
+
+static void *
+json_open(uschar *filename, uschar **errmsg)
+{
+FILE * f;
+
+json_set_alloc_funcs(json_malloc, json_free);
+
+if (!(f = Ufopen(filename, "rb")))
+  {
+  int save_errno = errno;
+  *errmsg = string_open_failed(errno, "%s for json search", filename);
+  errno = save_errno;
+  return NULL;
+  }
+return f;
+}
+
+
+
+/*************************************************
+*             Check entry point                  *
+*************************************************/
+
+static BOOL
+json_check(void *handle, uschar *filename, int modemask, uid_t *owners,
+  gid_t *owngroups, uschar **errmsg)
+{
+return lf_check_file(fileno((FILE *)handle), filename, S_IFREG, modemask,
+  owners, owngroups, "json", errmsg) == 0;
+}
+
+
+
+/*************************************************
+*         Find entry point for lsearch           *
+*************************************************/
+
+/* See local README for interface description */
+
+static int
+json_find(void *handle, uschar *filename, const uschar *keystring, int length,
+  uschar **result, uschar **errmsg, uint *do_cache)
+{
+FILE * f = handle;
+json_t * j, * j0;
+json_error_t jerr;
+uschar * key;
+int sep = 0;
+
+length = length;       /* Keep picky compilers happy */
+do_cache = do_cache;   /* Keep picky compilers happy */
+
+rewind(f);
+if (!(j = json_loadf(f, 0, &jerr)))
+  {
+  *errmsg = string_sprintf("json error on open: %.*s\n",
+       JSON_ERROR_TEXT_LENGTH, jerr.text);
+  return FAIL;
+  }
+j0 = j;
+
+for (int k = 1;  (key = string_nextinlist(&keystring, &sep, NULL, 0)); k++)
+  {
+  BOOL numeric = TRUE;
+  for (uschar * s = key; *s; s++) if (!isdigit(*s)) { numeric = FALSE; break; }
+
+  if (!(j = numeric
+       ? json_array_get(j, (size_t) strtoul(CS key, NULL, 10))
+       : json_object_get(j, CCS key)
+     ) )
+    {
+    DEBUG(D_lookup) debug_printf("%s, for key %d: '%s'\n",
+      numeric
+      ? US"bad index, or not json array"
+      : US"no such key, or not json object",
+      k, key);
+    json_decref(j0);
+    return FAIL;
+    }
+  }
+
+switch (json_typeof(j))
+  {
+  case JSON_STRING:
+    *result = string_copyn(CUS json_string_value(j), json_string_length(j));
+    break;
+  case JSON_INTEGER:
+    *result = string_sprintf("%" JSON_INTEGER_FORMAT, json_integer_value(j));
+    break;
+  case JSON_REAL:
+    *result = string_sprintf("%f", json_real_value(j));
+    break;
+  case JSON_TRUE:      *result = US"true";     break;
+  case JSON_FALSE:     *result = US"false";    break;
+  case JSON_NULL:      *result = NULL;         break;
+  default:             *result = US json_dumps(j, 0); break;
+  }
+json_decref(j0);
+return OK;
+}
+
+
+
+/*************************************************
+*              Close entry point                 *
+*************************************************/
+
+/* See local README for interface description */
+
+static void
+json_close(void *handle)
+{
+(void)fclose((FILE *)handle);
+}
+
+
+
+/*************************************************
+*         Version reporting entry point          *
+*************************************************/
+
+/* See local README for interface description. */
+
+#include "../version.h"
+
+void
+json_version_report(FILE *f)
+{
+fprintf(f, "Library version: json: Jansonn version %s\n", JANSSON_VERSION);
+}
+
+
+static lookup_info json_lookup_info = {
+  US"json",                      /* lookup name */
+  lookup_absfile,                /* uses absolute file name */
+  json_open,                  /* open function */
+  json_check,                 /* check function */
+  json_find,                  /* find function */
+  json_close,                 /* close function */
+  NULL,                          /* no tidy function */
+  NULL,                          /* no quoting function */
+  json_version_report         /* version reporting */
+};
+
+
+#ifdef DYNLOOKUP
+#define json_lookup_module_info _lookup_module_info
+#endif
+
+static lookup_info *_lookup_list[] = { &json_lookup_info };
+lookup_module_info json_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 1 };
+
+/* End of lookups/json.c */