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
__json_snprintf(char * buf,const int len,const char * format,...)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
rte_tel_json_empty_array(char * buf,const int len,const int used)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
rte_tel_json_empty_obj(char * buf,const int len,const int used)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
rte_tel_json_str(char * buf,const int len,const int used,const char * str)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
rte_tel_json_add_array_string(char * buf,const int len,const int used,const char * str)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
rte_tel_json_add_array_int(char * buf,const int len,const int used,int val)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
rte_tel_json_add_array_u64(char * buf,const int len,const int used,uint64_t val)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 raw JSON value to the JSON array stored in the
107 * provided buffer.
108 */
109 static inline int
rte_tel_json_add_array_json(char * buf,const int len,const int used,const char * str)110 rte_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 */
125 static inline int
rte_tel_json_add_obj_u64(char * buf,const int len,const int used,const char * name,uint64_t val)126 rte_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 */
143 static inline int
rte_tel_json_add_obj_int(char * buf,const int len,const int used,const char * name,int val)144 rte_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 */
161 static inline int
rte_tel_json_add_obj_str(char * buf,const int len,const int used,const char * name,const char * val)162 rte_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 */
178 static inline int
rte_tel_json_add_obj_json(char * buf,const int len,const int used,const char * name,const char * val)179 rte_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