src/libsystemd/sd-bus/bus-introspect.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3 ***/
   4
   5 #include <stdio_ext.h>
   6
   7 #include "bus-internal.h"
   8 #include "bus-introspect.h"
   9 #include "bus-protocol.h"
  10 #include "bus-signature.h"
  11 #include "fd-util.h"
  12 #include "fileio.h"
  13 #include "string-util.h"
  14 #include "util.h"
  15
  16 int introspect_begin(struct introspect *i, bool trusted) {
  17         assert(i);
  18
  19         zero(*i);
  20         i->trusted = trusted;
  21
  22         i->f = open_memstream(&i->introspection, &i->size);
  23         if (!i->f)
  24                 return -ENOMEM;
  25
  26         (void) __fsetlocking(i->f, FSETLOCKING_BYCALLER);
  27
  28         fputs(BUS_INTROSPECT_DOCTYPE
  29               "<node>\n", i->f);
  30
  31         return 0;
  32 }
  33
  34 int introspect_write_default_interfaces(struct introspect *i, bool object_manager) {
  35         assert(i);
  36
  37         fputs(BUS_INTROSPECT_INTERFACE_PEER
  38               BUS_INTROSPECT_INTERFACE_INTROSPECTABLE
  39               BUS_INTROSPECT_INTERFACE_PROPERTIES, i->f);
  40
  41         if (object_manager)
  42                 fputs(BUS_INTROSPECT_INTERFACE_OBJECT_MANAGER, i->f);
  43
  44         return 0;
  45 }
  46
  47 int introspect_write_child_nodes(struct introspect *i, Set *s, const char *prefix) {
  48         char *node;
  49
  50         assert(i);
  51         assert(prefix);
  52
  53         while ((node = set_steal_first(s))) {
  54                 const char *e;
  55
  56                 e = object_path_startswith(node, prefix);
  57                 if (e && e[0])
  58                         fprintf(i->f, " <node name=\"%s\"/>\n", e);
  59
  60                 free(node);
  61         }
  62
  63         return 0;
  64 }
  65
  66 static void introspect_write_flags(struct introspect *i, int type, int flags) {
  67         if (flags & SD_BUS_VTABLE_DEPRECATED)
  68                 fputs("   <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
  69
  70         if (type == _SD_BUS_VTABLE_METHOD && (flags & SD_BUS_VTABLE_METHOD_NO_REPLY))
  71                 fputs("   <annotation name=\"org.freedesktop.DBus.Method.NoReply\" value=\"true\"/>\n", i->f);
  72
  73         if (IN_SET(type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY)) {
  74                 if (flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
  75                         fputs("   <annotation name=\"org.freedesktop.systemd1.Explicit\" value=\"true\"/>\n", i->f);
  76
  77                 if (flags & SD_BUS_VTABLE_PROPERTY_CONST)
  78                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"const\"/>\n", i->f);
  79                 else if (flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)
  80                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"invalidates\"/>\n", i->f);
  81                 else if (!(flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
  82                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>\n", i->f);
  83         }
  84
  85         if (!i->trusted &&
  86             IN_SET(type, _SD_BUS_VTABLE_METHOD, _SD_BUS_VTABLE_WRITABLE_PROPERTY) &&
  87             !(flags & SD_BUS_VTABLE_UNPRIVILEGED))
  88                 fputs("   <annotation name=\"org.freedesktop.systemd1.Privileged\" value=\"true\"/>\n", i->f);
  89 }
  90
  91 static int introspect_write_arguments(struct introspect *i, const char *signature, const char *direction) {
  92         int r;
  93
  94         for (;;) {
  95                 size_t l;
  96
  97                 if (!*signature)
  98                         return 0;
  99
 100                 r = signature_element_length(signature, &l);
 101                 if (r < 0)
 102                         return r;
 103
 104                 fprintf(i->f, "   <arg type=\"%.*s\"", (int) l, signature);
 105
 106                 if (direction)
 107                         fprintf(i->f, " direction=\"%s\"/>\n", direction);
 108                 else
 109                         fputs("/>\n", i->f);
 110
 111                 signature += l;
 112         }
 113 }
 114
 115 int introspect_write_interface(struct introspect *i, const sd_bus_vtable *v) {
 116         assert(i);
 117         assert(v);
 118
 119         for (; v->type != _SD_BUS_VTABLE_END; v++) {
 120
 121                 /* Ignore methods, signals and properties that are
 122                  * marked "hidden", but do show the interface
 123                  * itself */
 124
 125                 if (v->type != _SD_BUS_VTABLE_START && (v->flags & SD_BUS_VTABLE_HIDDEN))
 126                         continue;
 127
 128                 switch (v->type) {
 129
 130                 case _SD_BUS_VTABLE_START:
 131                         if (v->flags & SD_BUS_VTABLE_DEPRECATED)
 132                                 fputs("  <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
 133                         break;
 134
 135                 case _SD_BUS_VTABLE_METHOD:
 136                         fprintf(i->f, "  <method name=\"%s\">\n", v->x.method.member);
 137                         introspect_write_arguments(i, strempty(v->x.method.signature), "in");
 138                         introspect_write_arguments(i, strempty(v->x.method.result), "out");
 139                         introspect_write_flags(i, v->type, v->flags);
 140                         fputs("  </method>\n", i->f);
 141                         break;
 142
 143                 case _SD_BUS_VTABLE_PROPERTY:
 144                 case _SD_BUS_VTABLE_WRITABLE_PROPERTY:
 145                         fprintf(i->f, "  <property name=\"%s\" type=\"%s\" access=\"%s\">\n",
 146                                 v->x.property.member,
 147                                 v->x.property.signature,
 148                                 v->type == _SD_BUS_VTABLE_WRITABLE_PROPERTY ? "readwrite" : "read");
 149                         introspect_write_flags(i, v->type, v->flags);
 150                         fputs("  </property>\n", i->f);
 151                         break;
 152
 153                 case _SD_BUS_VTABLE_SIGNAL:
 154                         fprintf(i->f, "  <signal name=\"%s\">\n", v->x.signal.member);
 155                         introspect_write_arguments(i, strempty(v->x.signal.signature), NULL);
 156                         introspect_write_flags(i, v->type, v->flags);
 157                         fputs("  </signal>\n", i->f);
 158                         break;
 159                 }
 160
 161         }
 162
 163         return 0;
 164 }
 165
 166 int introspect_finish(struct introspect *i, sd_bus *bus, sd_bus_message *m, sd_bus_message **reply) {
 167         sd_bus_message *q;
 168         int r;
 169
 170         assert(i);
 171         assert(m);
 172         assert(reply);
 173
 174         fputs("</node>\n", i->f);
 175
 176         r = fflush_and_check(i->f);
 177         if (r < 0)
 178                 return r;
 179
 180         r = sd_bus_message_new_method_return(m, &q);
 181         if (r < 0)
 182                 return r;
 183
 184         r = sd_bus_message_append(q, "s", i->introspection);
 185         if (r < 0) {
 186                 sd_bus_message_unref(q);
 187                 return r;
 188         }
 189
 190         *reply = q;
 191         return 0;
 192 }
 193
 194 void introspect_free(struct introspect *i) {
 195         assert(i);
 196
 197         safe_fclose(i->f);
 198
 199         free(i->introspection);
 200         zero(*i);
 201 }