ceph/src/spdk/dpdk/lib/librte_telemetry/telemetry_json.h

   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)
  29 static 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. */
  47 static inline int
  48 rte_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. */
  54 static inline int
  55 rte_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. */
  61 static inline int
  62 rte_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. */
  68 static inline int
  69 rte_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. */
  81 static inline int
  82 rte_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. */
  93 static inline int
  94 rte_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 uint64_t value to the JSON object stored in the
 107  * provided buffer.
 108  */
 109 static inline int
 110 rte_tel_json_add_obj_u64(char *buf, const int len, const int used,
 111                 const char *name, uint64_t val)
 112 {
 113         int ret, end = used - 1;
 114         if (used <= 2) /* assume empty, since minimum is '{}' */
 115                 return __json_snprintf(buf, len, "{\"%s\":%"PRIu64"}", name,
 116                                 val);
 117
 118         ret = __json_snprintf(buf + end, len - end, ",\"%s\":%"PRIu64"}",
 119                         name, val);
 120         return ret == 0 ? used : end + ret;
 121 }
 122
 123 /**
 124  * Add a new element with int value to the JSON object stored in the
 125  * provided buffer.
 126  */
 127 static inline int
 128 rte_tel_json_add_obj_int(char *buf, const int len, const int used,
 129                 const char *name, int val)
 130 {
 131         int ret, end = used - 1;
 132         if (used <= 2) /* assume empty, since minimum is '{}' */
 133                 return __json_snprintf(buf, len, "{\"%s\":%d}", name,
 134                                 val);
 135
 136         ret = __json_snprintf(buf + end, len - end, ",\"%s\":%d}",
 137                         name, val);
 138         return ret == 0 ? used : end + ret;
 139 }
 140
 141 /**
 142  * Add a new element with string value to the JSON object stored in the
 143  * provided buffer.
 144  */
 145 static inline int
 146 rte_tel_json_add_obj_str(char *buf, const int len, const int used,
 147                 const char *name, const char *val)
 148 {
 149         int ret, end = used - 1;
 150         if (used <= 2) /* assume empty, since minimum is '{}' */
 151                 return __json_snprintf(buf, len, "{\"%s\":\"%s\"}", name, val);
 152
 153         ret = __json_snprintf(buf + end, len - end, ",\"%s\":\"%s\"}",
 154                         name, val);
 155         return ret == 0 ? used : end + ret;
 156 }
 157
 158 #endif /*_RTE_TELEMETRY_JSON_H_*/