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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include "bus-internal.h"
   4 #include "bus-introspect.h"
   5 #include "bus-objects.h"
   6 #include "bus-protocol.h"
   7 #include "bus-signature.h"
   8 #include "fd-util.h"
   9 #include "fileio.h"
  10 #include "memory-util.h"
  11 #include "string-util.h"
  12
  13 int introspect_begin(struct introspect *i, bool trusted) {
  14         assert(i);
  15
  16         zero(*i);
  17         i->trusted = trusted;
  18
  19         i->f = open_memstream_unlocked(&i->introspection, &i->size);
  20         if (!i->f)
  21                 return -ENOMEM;
  22
  23         fputs(BUS_INTROSPECT_DOCTYPE
  24               "<node>\n", i->f);
  25
  26         return 0;
  27 }
  28
  29 int introspect_write_default_interfaces(struct introspect *i, bool object_manager) {
  30         assert(i);
  31
  32         fputs(BUS_INTROSPECT_INTERFACE_PEER
  33               BUS_INTROSPECT_INTERFACE_INTROSPECTABLE
  34               BUS_INTROSPECT_INTERFACE_PROPERTIES, i->f);
  35
  36         if (object_manager)
  37                 fputs(BUS_INTROSPECT_INTERFACE_OBJECT_MANAGER, i->f);
  38
  39         return 0;
  40 }
  41
  42 int introspect_write_child_nodes(struct introspect *i, Set *s, const char *prefix) {
  43         char *node;
  44
  45         assert(i);
  46         assert(prefix);
  47
  48         while ((node = set_steal_first(s))) {
  49                 const char *e;
  50
  51                 e = object_path_startswith(node, prefix);
  52                 if (e && e[0])
  53                         fprintf(i->f, " <node name=\"%s\"/>\n", e);
  54
  55                 free(node);
  56         }
  57
  58         return 0;
  59 }
  60
  61 static void introspect_write_flags(struct introspect *i, int type, uint64_t flags) {
  62         if (flags & SD_BUS_VTABLE_DEPRECATED)
  63                 fputs("   <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
  64
  65         if (type == _SD_BUS_VTABLE_METHOD && (flags & SD_BUS_VTABLE_METHOD_NO_REPLY))
  66                 fputs("   <annotation name=\"org.freedesktop.DBus.Method.NoReply\" value=\"true\"/>\n", i->f);
  67
  68         if (IN_SET(type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY)) {
  69                 if (flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
  70                         fputs("   <annotation name=\"org.freedesktop.systemd1.Explicit\" value=\"true\"/>\n", i->f);
  71
  72                 if (flags & SD_BUS_VTABLE_PROPERTY_CONST)
  73                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"const\"/>\n", i->f);
  74                 else if (flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)
  75                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"invalidates\"/>\n", i->f);
  76                 else if (!(flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
  77                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>\n", i->f);
  78         }
  79
  80         if (!i->trusted &&
  81             IN_SET(type, _SD_BUS_VTABLE_METHOD, _SD_BUS_VTABLE_WRITABLE_PROPERTY) &&
  82             !(flags & SD_BUS_VTABLE_UNPRIVILEGED))
  83                 fputs("   <annotation name=\"org.freedesktop.systemd1.Privileged\" value=\"true\"/>\n", i->f);
  84 }
  85
  86 /* Note that "names" is both an input and an output parameter. It initially points to the first argument name in a
  87    NULL-separated list of strings, and is then advanced with each argument, and the resulting pointer is returned. */
  88 static int introspect_write_arguments(struct introspect *i, const char *signature, const char **names, const char *direction) {
  89         int r;
  90
  91         for (;;) {
  92                 size_t l;
  93
  94                 if (!*signature)
  95                         return 0;
  96
  97                 r = signature_element_length(signature, &l);
  98                 if (r < 0)
  99                         return r;
 100
 101                 fprintf(i->f, "   <arg type=\"%.*s\"", (int) l, signature);
 102
 103                 if (**names != '\0') {
 104                         fprintf(i->f, " name=\"%s\"", *names);
 105                         *names += strlen(*names) + 1;
 106                 }
 107
 108                 if (direction)
 109                         fprintf(i->f, " direction=\"%s\"/>\n", direction);
 110                 else
 111                         fputs("/>\n", i->f);
 112
 113                 signature += l;
 114         }
 115 }
 116
 117 int introspect_write_interface(struct introspect *i, const sd_bus_vtable *v) {
 118         const sd_bus_vtable *vtable = v;
 119         const char *names = "";
 120
 121         assert(i);
 122         assert(v);
 123
 124         for (; v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(vtable, v)) {
 125
 126                 /* Ignore methods, signals and properties that are
 127                  * marked "hidden", but do show the interface
 128                  * itself */
 129
 130                 if (v->type != _SD_BUS_VTABLE_START && (v->flags & SD_BUS_VTABLE_HIDDEN))
 131                         continue;
 132
 133                 switch (v->type) {
 134
 135                 case _SD_BUS_VTABLE_START:
 136                         if (v->flags & SD_BUS_VTABLE_DEPRECATED)
 137                                 fputs("  <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
 138                         break;
 139
 140                 case _SD_BUS_VTABLE_METHOD:
 141                         fprintf(i->f, "  <method name=\"%s\">\n", v->x.method.member);
 142                         if (bus_vtable_has_names(vtable))
 143                                 names = strempty(v->x.method.names);
 144                         introspect_write_arguments(i, strempty(v->x.method.signature), &names, "in");
 145                         introspect_write_arguments(i, strempty(v->x.method.result), &names, "out");
 146                         introspect_write_flags(i, v->type, v->flags);
 147                         fputs("  </method>\n", i->f);
 148                         break;
 149
 150                 case _SD_BUS_VTABLE_PROPERTY:
 151                 case _SD_BUS_VTABLE_WRITABLE_PROPERTY:
 152                         fprintf(i->f, "  <property name=\"%s\" type=\"%s\" access=\"%s\">\n",
 153                                 v->x.property.member,
 154                                 v->x.property.signature,
 155                                 v->type == _SD_BUS_VTABLE_WRITABLE_PROPERTY ? "readwrite" : "read");
 156                         introspect_write_flags(i, v->type, v->flags);
 157                         fputs("  </property>\n", i->f);
 158                         break;
 159
 160                 case _SD_BUS_VTABLE_SIGNAL:
 161                         fprintf(i->f, "  <signal name=\"%s\">\n", v->x.signal.member);
 162                         if (bus_vtable_has_names(vtable))
 163                                 names = strempty(v->x.method.names);
 164                         introspect_write_arguments(i, strempty(v->x.signal.signature), &names, NULL);
 165                         introspect_write_flags(i, v->type, v->flags);
 166                         fputs("  </signal>\n", i->f);
 167                         break;
 168                 }
 169
 170         }
 171
 172         return 0;
 173 }
 174
 175 int introspect_finish(struct introspect *i, sd_bus *bus, sd_bus_message *m, sd_bus_message **reply) {
 176         sd_bus_message *q;
 177         int r;
 178
 179         assert(i);
 180         assert(m);
 181         assert(reply);
 182
 183         fputs("</node>\n", i->f);
 184
 185         r = fflush_and_check(i->f);
 186         if (r < 0)
 187                 return r;
 188
 189         r = sd_bus_message_new_method_return(m, &q);
 190         if (r < 0)
 191                 return r;
 192
 193         r = sd_bus_message_append(q, "s", i->introspection);
 194         if (r < 0) {
 195                 sd_bus_message_unref(q);
 196                 return r;
 197         }
 198
 199         *reply = q;
 200         return 0;
 201 }
 202
 203 void introspect_free(struct introspect *i) {
 204         assert(i);
 205
 206         safe_fclose(i->f);
 207
 208         free(i->introspection);
 209         zero(*i);
 210 }