wiretap/json.c

   1 /* json.c
   2  *
   3  * Copyright 2015, Dario Lombardo <lomato@gmail.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-or-later
   6  */
   7
   8 #include "config.h"
   9
  10 #include <string.h>
  11
  12 #include "wtap-int.h"
  13 #include "file_wrappers.h"
  14
  15 #include "json.h"
  16 #include <wsutil/wsjson.h>
  17
  18 /* Maximum size of json file. */
  19 #define MAX_FILE_SIZE  (50*1024*1024)
  20
  21 static int json_file_type_subtype = -1;
  22
  23 void register_json(void);
  24
  25 wtap_open_return_val json_open(wtap *wth, int *err, char **err_info)
  26 {
  27     uint8_t* filebuf;
  28     int bytes_read;
  29
  30     /* XXX checking the full file contents might be a bit expensive, maybe
  31      * resort to simpler heuristics like '{' or '[' (with some other chars)? */
  32     filebuf = (uint8_t*)g_malloc0(MAX_FILE_SIZE);
  33     if (!filebuf)
  34         return WTAP_OPEN_ERROR;
  35
  36     bytes_read = file_read(filebuf, MAX_FILE_SIZE, wth->fh);
  37     if (bytes_read < 0) {
  38         /* Read error. */
  39         *err = file_error(wth->fh, err_info);
  40         g_free(filebuf);
  41         return WTAP_OPEN_ERROR;
  42     }
  43     if (bytes_read == 0) {
  44         /* empty file, not *anybody's* */
  45         g_free(filebuf);
  46         return WTAP_OPEN_NOT_MINE;
  47     }
  48
  49     if (json_validate(filebuf, bytes_read) == false) {
  50         g_free(filebuf);
  51         return WTAP_OPEN_NOT_MINE;
  52     }
  53
  54     if (file_seek(wth->fh, 0, SEEK_SET, err) == -1) {
  55         g_free(filebuf);
  56         return WTAP_OPEN_ERROR;
  57     }
  58
  59     wth->file_type_subtype = json_file_type_subtype;
  60     wth->file_encap = WTAP_ENCAP_JSON;
  61     wth->file_tsprec = WTAP_TSPREC_SEC;
  62     wth->subtype_read = wtap_full_file_read;
  63     wth->subtype_seek_read = wtap_full_file_seek_read;
  64     wth->snapshot_length = 0;
  65
  66     g_free(filebuf);
  67     return WTAP_OPEN_MINE;
  68 }
  69
  70 static const struct supported_block_type json_blocks_supported[] = {
  71     /*
  72      * This is a file format that we dissect, so we provide only one
  73      * "packet" with the file's contents, and don't support any
  74      * options.
  75      */
  76     { WTAP_BLOCK_PACKET, ONE_BLOCK_SUPPORTED, NO_OPTIONS_SUPPORTED }
  77 };
  78
  79 static const struct file_type_subtype_info json_info = {
  80     "JavaScript Object Notation", "json", "json", NULL,
  81     false, BLOCKS_SUPPORTED(json_blocks_supported),
  82     NULL, NULL, NULL
  83 };
  84
  85 void register_json(void)
  86 {
  87     json_file_type_subtype = wtap_register_file_type_subtype(&json_info);
  88
  89     /*
  90      * Register name for backwards compatibility with the
  91      * wtap_filetypes table in Lua.
  92      */
  93     wtap_register_backwards_compatibility_lua_name("JSON",
  94                                                    json_file_type_subtype);
  95 }
  96
  97 /*
  98  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  99  *
 100  * Local variables:
 101  * c-basic-offset: 4
 102  * tab-width: 8
 103  * indent-tabs-mode: nil
 104  * End:
 105  *
 106  * vi: set shiftwidth=4 tabstop=8 expandtab:
 107  * :indentSize=4:tabSize=8:noTabs=true:
 108  */