LXR dpdk/lib/librte_telemetry/telemetry

   1/* SPDX-License-Identifier: BSD-3-Clause
   2 * Copyright(c) 2020 Intel Corporation
   3 */
   4
   5#ifndef _RTE_TELEMETRY_JSON_H_
   6#define _RTE_TELEMETRY_JSON_H_
   7
   8#include <inttypes.h>
   9#include <stdarg.h>
  10#include <stdio.h>
  11#include <rte_common.h>
  12
  13/**
  14 * @file
  15 * Internal Telemetry Utility functions
  16 *
  17 * This file contains small inline functions to make it easier for applications
  18 * to build up valid JSON responses to telemetry requests.
  19 *
  20 ***/
  21
  22/**
  23 * @internal
  24 * Copies a value into a buffer if the buffer has enough available space.
  25 * Nothing written to buffer if an overflow ocurs.
  26 * This function is not for use for values larger than 1k.
  27 */
  28__rte_format_printf(3, 4)
  29static inline int
  30__json_snprintf(char *buf, const int len, const char *format, ...)
  31{
  32        char tmp[1024];
  33        va_list ap;
  34        int ret;
  35
  36        va_start(ap, format);
  37        ret = vsnprintf(tmp, sizeof(tmp), format, ap);
  38        va_end(ap);
  39        if (ret > 0 && ret < (int)sizeof(tmp) && ret < len) {
  40                strcpy(buf, tmp);
  41                return ret;
  42        }
  43        return 0; /* nothing written or modified */
  44}
  45
  46/* Copies an empty array into the provided buffer. */
  47static inline int
  48rte_tel_json_empty_array(char *buf, const int len, const int used)
  49{
  50        return used + __json_snprintf(buf + used, len - used, "[]");
  51}
  52
  53/* Copies an empty object into the provided buffer. */
  54static inline int
  55rte_tel_json_empty_obj(char *buf, const int len, const int used)
  56{
  57        return used + __json_snprintf(buf + used, len - used, "{}");
  58}
  59
  60/* Copies a string into the provided buffer, in JSON format. */
  61static inline int
  62rte_tel_json_str(char *buf, const int len, const int used, const char *str)
  63{
  64        return used + __json_snprintf(buf + used, len - used, "\"%s\"", str);
  65}
  66
  67/* Appends a string into the JSON array in the provided buffer. */
  68static inline int
  69rte_tel_json_add_array_string(char *buf, const int len, const int used,
  70                const char *str)
  71{
  72        int ret, end = used - 1; /* strip off final delimiter */
  73        if (used <= 2) /* assume empty, since minimum is '[]' */
  74                return __json_snprintf(buf, len, "[\"%s\"]", str);
  75
  76        ret = __json_snprintf(buf + end, len - end, ",\"%s\"]", str);
  77        return ret == 0 ? used : end + ret;
  78}
  79
  80/* Appends an integer into the JSON array in the provided buffer. */
  81static inline int
  82rte_tel_json_add_array_int(char *buf, const int len, const int used, int val)
  83{
  84        int ret, end = used - 1; /* strip off final delimiter */
  85        if (used <= 2) /* assume empty, since minimum is '[]' */
  86                return __json_snprintf(buf, len, "[%d]", val);
  87
  88        ret = __json_snprintf(buf + end, len - end, ",%d]", val);
  89        return ret == 0 ? used : end + ret;
  90}
  91
  92/* Appends a uint64_t into the JSON array in the provided buffer. */
  93static inline int
  94rte_tel_json_add_array_u64(char *buf, const int len, const int used,
  95                uint64_t val)
  96{
  97        int ret, end = used - 1; /* strip off final delimiter */
  98        if (used <= 2) /* assume empty, since minimum is '[]' */
  99                return __json_snprintf(buf, len, "[%"PRIu64"]", val);
 100
 101        ret = __json_snprintf(buf + end, len - end, ",%"PRIu64"]", val);
 102        return ret == 0 ? used : end + ret;
 103}
 104
 105/*
 106 * Add a new element with raw JSON value to the JSON array stored in the
 107 * provided buffer.
 108 */
 109static inline int
 110rte_tel_json_add_array_json(char *buf, const int len, const int used,
 111                const char *str)
 112{
 113        int ret, end = used - 1; /* strip off final delimiter */
 114        if (used <= 2) /* assume empty, since minimum is '[]' */
 115                return __json_snprintf(buf, len, "[%s]", str);
 116
 117        ret = __json_snprintf(buf + end, len - end, ",%s]", str);
 118        return ret == 0 ? used : end + ret;
 119}
 120
 121/**
 122 * Add a new element with uint64_t value to the JSON object stored in the
 123 * provided buffer.
 124 */
 125static inline int
 126rte_tel_json_add_obj_u64(char *buf, const int len, const int used,
 127                const char *name, uint64_t val)
 128{
 129        int ret, end = used - 1;
 130        if (used <= 2) /* assume empty, since minimum is '{}' */
 131                return __json_snprintf(buf, len, "{\"%s\":%"PRIu64"}", name,
 132                                val);
 133
 134        ret = __json_snprintf(buf + end, len - end, ",\"%s\":%"PRIu64"}",
 135                        name, val);
 136        return ret == 0 ? used : end + ret;
 137}
 138
 139/**
 140 * Add a new element with int value to the JSON object stored in the
 141 * provided buffer.
 142 */
 143static inline int
 144rte_tel_json_add_obj_int(char *buf, const int len, const int used,
 145                const char *name, int val)
 146{
 147        int ret, end = used - 1;
 148        if (used <= 2) /* assume empty, since minimum is '{}' */
 149                return __json_snprintf(buf, len, "{\"%s\":%d}", name,
 150                                val);
 151
 152        ret = __json_snprintf(buf + end, len - end, ",\"%s\":%d}",
 153                        name, val);
 154        return ret == 0 ? used : end + ret;
 155}
 156
 157/**
 158 * Add a new element with string value to the JSON object stored in the
 159 * provided buffer.
 160 */
 161static inline int
 162rte_tel_json_add_obj_str(char *buf, const int len, const int used,
 163                const char *name, const char *val)
 164{
 165        int ret, end = used - 1;
 166        if (used <= 2) /* assume empty, since minimum is '{}' */
 167                return __json_snprintf(buf, len, "{\"%s\":\"%s\"}", name, val);
 168
 169        ret = __json_snprintf(buf + end, len - end, ",\"%s\":\"%s\"}",
 170                        name, val);
 171        return ret == 0 ? used : end + ret;
 172}
 173
 174/**
 175 * Add a new element with raw JSON value to the JSON object stored in the
 176 * provided buffer.
 177 */
 178static inline int
 179rte_tel_json_add_obj_json(char *buf, const int len, const int used,
 180                const char *name, const char *val)
 181{
 182        int ret, end = used - 1;
 183        if (used <= 2) /* assume empty, since minimum is '{}' */
 184                return __json_snprintf(buf, len, "{\"%s\":%s}", name, val);
 185
 186        ret = __json_snprintf(buf + end, len - end, ",\"%s\":%s}",
 187                        name, val);
 188        return ret == 0 ? used : end + ret;
 189}
 190
 191#endif /*_RTE_TELEMETRY_JSON_H_*/
 192