xref: /openbmc/qemu/qobject/qjson.c (revision 91f54d92) 
1 /*
2  * QObject JSON integration
3  *
4  * Copyright IBM, Corp. 2009
5  *
6  * Authors:
7  *  Anthony Liguori   <aliguori@us.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
10  * See the COPYING.LIB file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 #include "qapi/error.h"
16 #include "qapi/qmp/json-parser.h"
17 #include "qapi/qmp/qjson.h"
18 #include "qapi/qmp/qbool.h"
19 #include "qapi/qmp/qdict.h"
20 #include "qapi/qmp/qlist.h"
21 #include "qapi/qmp/qnum.h"
22 #include "qapi/qmp/qstring.h"
23 #include "qemu/unicode.h"
24 
25 typedef struct JSONParsingState
26 {
27     JSONMessageParser parser;
28     QObject *result;
29     Error *err;
30 } JSONParsingState;
31 
32 static void consume_json(void *opaque, QObject *json, Error *err)
33 {
34     JSONParsingState *s = opaque;
35 
36     assert(!json != !err);
37     assert(!s->result || !s->err);
38 
39     if (s->result) {
40         qobject_unref(s->result);
41         s->result = NULL;
42         error_setg(&s->err, "Expecting at most one JSON value");
43     }
44     if (s->err) {
45         qobject_unref(json);
46         error_free(err);
47         return;
48     }
49     s->result = json;
50     s->err = err;
51 }
52 
53 /*
54  * Parse @string as JSON value.
55  * If @ap is non-null, interpolate %-escapes.
56  * Takes ownership of %p arguments.
57  * On success, return the JSON value.
58  * On failure, store an error through @errp and return NULL.
59  * Ownership of %p arguments becomes indeterminate then.  To avoid
60  * leaks, callers passing %p must terminate on error, e.g. by passing
61  * &error_abort.
62  */
63 static QObject *qobject_from_jsonv(const char *string, va_list *ap,
64                                    Error **errp)
65 {
66     JSONParsingState state = {};
67 
68     json_message_parser_init(&state.parser, consume_json, &state, ap);
69     json_message_parser_feed(&state.parser, string, strlen(string));
70     json_message_parser_flush(&state.parser);
71     json_message_parser_destroy(&state.parser);
72 
73     if (!state.result && !state.err) {
74         error_setg(&state.err, "Expecting a JSON value");
75     }
76 
77     error_propagate(errp, state.err);
78     return state.result;
79 }
80 
81 QObject *qobject_from_json(const char *string, Error **errp)
82 {
83     return qobject_from_jsonv(string, NULL, errp);
84 }
85 
86 /*
87  * Parse @string as JSON value with %-escapes interpolated.
88  * Abort on error.  Do not use with untrusted @string.
89  * Return the resulting QObject.  It is never null.
90  */
91 QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap)
92 {
93     va_list ap_copy;
94     QObject *obj;
95 
96     /* va_copy() is needed when va_list is an array type */
97     va_copy(ap_copy, ap);
98     obj = qobject_from_jsonv(string, &ap_copy, &error_abort);
99     va_end(ap_copy);
100 
101     assert(obj);
102     return obj;
103 }
104 
105 /*
106  * Parse @string as JSON value with %-escapes interpolated.
107  * Abort on error.  Do not use with untrusted @string.
108  * Return the resulting QObject.  It is never null.
109  */
110 QObject *qobject_from_jsonf_nofail(const char *string, ...)
111 {
112     QObject *obj;
113     va_list ap;
114 
115     va_start(ap, string);
116     obj = qobject_from_vjsonf_nofail(string, ap);
117     va_end(ap);
118 
119     return obj;
120 }
121 
122 /*
123  * Parse @string as JSON object with %-escapes interpolated.
124  * Abort on error.  Do not use with untrusted @string.
125  * Return the resulting QDict.  It is never null.
126  */
127 QDict *qdict_from_vjsonf_nofail(const char *string, va_list ap)
128 {
129     QDict *qdict;
130 
131     qdict = qobject_to(QDict, qobject_from_vjsonf_nofail(string, ap));
132     assert(qdict);
133     return qdict;
134 }
135 
136 /*
137  * Parse @string as JSON object with %-escapes interpolated.
138  * Abort on error.  Do not use with untrusted @string.
139  * Return the resulting QDict.  It is never null.
140  */
141 QDict *qdict_from_jsonf_nofail(const char *string, ...)
142 {
143     QDict *qdict;
144     va_list ap;
145 
146     va_start(ap, string);
147     qdict = qdict_from_vjsonf_nofail(string, ap);
148     va_end(ap);
149     return qdict;
150 }
151 
152 static void json_pretty_newline(GString *accu, bool pretty, int indent)
153 {
154     if (pretty) {
155         g_string_append_printf(accu, "\n%*s", indent * 4, "");
156     }
157 }
158 
159 static void quoted_str(const char *str, GString *accu)
160 {
161     const char *ptr;
162     int cp;
163     char *end;
164 
165     g_string_append_c(accu, '"');
166 
167     for (ptr = str; *ptr; ptr = end) {
168         cp = mod_utf8_codepoint(ptr, 6, &end);
169         switch (cp) {
170         case '\"':
171             g_string_append(accu, "\\\"");
172             break;
173         case '\\':
174             g_string_append(accu, "\\\\");
175             break;
176         case '\b':
177             g_string_append(accu, "\\b");
178             break;
179         case '\f':
180             g_string_append(accu, "\\f");
181             break;
182         case '\n':
183             g_string_append(accu, "\\n");
184             break;
185         case '\r':
186             g_string_append(accu, "\\r");
187             break;
188         case '\t':
189             g_string_append(accu, "\\t");
190             break;
191         default:
192             if (cp < 0) {
193                 cp = 0xFFFD; /* replacement character */
194             }
195             if (cp > 0xFFFF) {
196                 /* beyond BMP; need a surrogate pair */
197                 g_string_append_printf(accu, "\\u%04X\\u%04X",
198                                        0xD800 + ((cp - 0x10000) >> 10),
199                                        0xDC00 + ((cp - 0x10000) & 0x3FF));
200             } else if (cp < 0x20 || cp >= 0x7F) {
201                 g_string_append_printf(accu, "\\u%04X", cp);
202             } else {
203                 g_string_append_c(accu, cp);
204             }
205         }
206     };
207 
208     g_string_append_c(accu, '"');
209 }
210 
211 static void to_json(const QObject *obj, GString *accu, bool pretty, int indent)
212 {
213     switch (qobject_type(obj)) {
214     case QTYPE_QNULL:
215         g_string_append(accu, "null");
216         break;
217     case QTYPE_QNUM: {
218         QNum *val = qobject_to(QNum, obj);
219         char *buffer = qnum_to_string(val);
220         g_string_append(accu, buffer);
221         g_free(buffer);
222         break;
223     }
224     case QTYPE_QSTRING: {
225         quoted_str(qstring_get_str(qobject_to(QString, obj)), accu);
226         break;
227     }
228     case QTYPE_QDICT: {
229         QDict *val = qobject_to(QDict, obj);
230         const char *comma = pretty ? "," : ", ";
231         const char *sep = "";
232         const QDictEntry *entry;
233 
234         g_string_append_c(accu, '{');
235 
236         for (entry = qdict_first(val);
237              entry;
238              entry = qdict_next(val, entry)) {
239             g_string_append(accu, sep);
240             json_pretty_newline(accu, pretty, indent + 1);
241             quoted_str(qdict_entry_key(entry), accu);
242             g_string_append(accu, ": ");
243             to_json(qdict_entry_value(entry), accu, pretty, indent + 1);
244             sep = comma;
245         }
246 
247         json_pretty_newline(accu, pretty, indent);
248         g_string_append_c(accu, '}');
249         break;
250     }
251     case QTYPE_QLIST: {
252         QList *val = qobject_to(QList, obj);
253         const char *comma = pretty ? "," : ", ";
254         const char *sep = "";
255         QListEntry *entry;
256 
257         g_string_append_c(accu, '[');
258 
259         QLIST_FOREACH_ENTRY(val, entry) {
260             g_string_append(accu, sep);
261             json_pretty_newline(accu, pretty, indent + 1);
262             to_json(qlist_entry_obj(entry), accu, pretty, indent + 1);
263             sep = comma;
264         }
265 
266         json_pretty_newline(accu, pretty, indent);
267         g_string_append_c(accu, ']');
268         break;
269     }
270     case QTYPE_QBOOL: {
271         QBool *val = qobject_to(QBool, obj);
272 
273         if (qbool_get_bool(val)) {
274             g_string_append(accu, "true");
275         } else {
276             g_string_append(accu, "false");
277         }
278         break;
279     }
280     default:
281         abort();
282     }
283 }
284 
285 GString *qobject_to_json_pretty(const QObject *obj, bool pretty)
286 {
287     GString *accu = g_string_new(NULL);
288 
289     to_json(obj, accu, pretty, 0);
290     return accu;
291 }
292 
293 GString *qobject_to_json(const QObject *obj)
294 {
295     return qobject_to_json_pretty(obj, false);
296 }
297