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

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