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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2013 Lennart Poettering
   6 ***/
   7
   8 #include <stdio_ext.h>
   9
  10 #include "bus-internal.h"
  11 #include "bus-introspect.h"
  12 #include "bus-protocol.h"
  13 #include "bus-signature.h"
  14 #include "fd-util.h"
  15 #include "fileio.h"
  16 #include "string-util.h"
  17 #include "util.h"
  18
  19 int introspect_begin(struct introspect *i, bool trusted) {
  20         assert(i);
  21
  22         zero(*i);
  23         i->trusted = trusted;
  24
  25         i->f = open_memstream(&i->introspection, &i->size);
  26         if (!i->f)
  27                 return -ENOMEM;
  28
  29         (void) __fsetlocking(i->f, FSETLOCKING_BYCALLER);
  30
  31         fputs(BUS_INTROSPECT_DOCTYPE
  32               "<node>\n", i->f);
  33
  34         return 0;
  35 }
  36
  37 int introspect_write_default_interfaces(struct introspect *i, bool object_manager) {
  38         assert(i);
  39
  40         fputs(BUS_INTROSPECT_INTERFACE_PEER
  41               BUS_INTROSPECT_INTERFACE_INTROSPECTABLE
  42               BUS_INTROSPECT_INTERFACE_PROPERTIES, i->f);
  43
  44         if (object_manager)
  45                 fputs(BUS_INTROSPECT_INTERFACE_OBJECT_MANAGER, i->f);
  46
  47         return 0;
  48 }
  49
  50 int introspect_write_child_nodes(struct introspect *i, Set *s, const char *prefix) {
  51         char *node;
  52
  53         assert(i);
  54         assert(prefix);
  55
  56         while ((node = set_steal_first(s))) {
  57                 const char *e;
  58
  59                 e = object_path_startswith(node, prefix);
  60                 if (e && e[0])
  61                         fprintf(i->f, " <node name=\"%s\"/>\n", e);
  62
  63                 free(node);
  64         }
  65
  66         return 0;
  67 }
  68
  69 static void introspect_write_flags(struct introspect *i, int type, int flags) {
  70         if (flags & SD_BUS_VTABLE_DEPRECATED)
  71                 fputs("   <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
  72
  73         if (type == _SD_BUS_VTABLE_METHOD && (flags & SD_BUS_VTABLE_METHOD_NO_REPLY))
  74                 fputs("   <annotation name=\"org.freedesktop.DBus.Method.NoReply\" value=\"true\"/>\n", i->f);
  75
  76         if (IN_SET(type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY)) {
  77                 if (flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
  78                         fputs("   <annotation name=\"org.freedesktop.systemd1.Explicit\" value=\"true\"/>\n", i->f);
  79
  80                 if (flags & SD_BUS_VTABLE_PROPERTY_CONST)
  81                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"const\"/>\n", i->f);
  82                 else if (flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)
  83                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"invalidates\"/>\n", i->f);
  84                 else if (!(flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
  85                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>\n", i->f);
  86         }
  87
  88         if (!i->trusted &&
  89             IN_SET(type, _SD_BUS_VTABLE_METHOD, _SD_BUS_VTABLE_WRITABLE_PROPERTY) &&
  90             !(flags & SD_BUS_VTABLE_UNPRIVILEGED))
  91                 fputs("   <annotation name=\"org.freedesktop.systemd1.Privileged\" value=\"true\"/>\n", i->f);
  92 }
  93
  94 static int introspect_write_arguments(struct introspect *i, const char *signature, const char *direction) {
  95         int r;
  96
  97         for (;;) {
  98                 size_t l;
  99
 100                 if (!*signature)
 101                         return 0;
 102
 103                 r = signature_element_length(signature, &l);
 104                 if (r < 0)
 105                         return r;
 106
 107                 fprintf(i->f, "   <arg type=\"%.*s\"", (int) l, signature);
 108
 109                 if (direction)
 110                         fprintf(i->f, " direction=\"%s\"/>\n", direction);
 111                 else
 112                         fputs("/>\n", i->f);
 113
 114                 signature += l;
 115         }
 116 }
 117
 118 int introspect_write_interface(struct introspect *i, const sd_bus_vtable *v) {
 119         assert(i);
 120         assert(v);
 121
 122         for (; v->type != _SD_BUS_VTABLE_END; v++) {
 123
 124                 /* Ignore methods, signals and properties that are
 125                  * marked "hidden", but do show the interface
 126                  * itself */
 127
 128                 if (v->type != _SD_BUS_VTABLE_START && (v->flags & SD_BUS_VTABLE_HIDDEN))
 129                         continue;
 130
 131                 switch (v->type) {
 132
 133                 case _SD_BUS_VTABLE_START:
 134                         if (v->flags & SD_BUS_VTABLE_DEPRECATED)
 135                                 fputs("  <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
 136                         break;
 137
 138                 case _SD_BUS_VTABLE_METHOD:
 139                         fprintf(i->f, "  <method name=\"%s\">\n", v->x.method.member);
 140                         introspect_write_arguments(i, strempty(v->x.method.signature), "in");
 141                         introspect_write_arguments(i, strempty(v->x.method.result), "out");
 142                         introspect_write_flags(i, v->type, v->flags);
 143                         fputs("  </method>\n", i->f);
 144                         break;
 145
 146                 case _SD_BUS_VTABLE_PROPERTY:
 147                 case _SD_BUS_VTABLE_WRITABLE_PROPERTY:
 148                         fprintf(i->f, "  <property name=\"%s\" type=\"%s\" access=\"%s\">\n",
 149                                 v->x.property.member,
 150                                 v->x.property.signature,
 151                                 v->type == _SD_BUS_VTABLE_WRITABLE_PROPERTY ? "readwrite" : "read");
 152                         introspect_write_flags(i, v->type, v->flags);
 153                         fputs("  </property>\n", i->f);
 154                         break;
 155
 156                 case _SD_BUS_VTABLE_SIGNAL:
 157                         fprintf(i->f, "  <signal name=\"%s\">\n", v->x.signal.member);
 158                         introspect_write_arguments(i, strempty(v->x.signal.signature), NULL);
 159                         introspect_write_flags(i, v->type, v->flags);
 160                         fputs("  </signal>\n", i->f);
 161                         break;
 162                 }
 163
 164         }
 165
 166         return 0;
 167 }
 168
 169 int introspect_finish(struct introspect *i, sd_bus *bus, sd_bus_message *m, sd_bus_message **reply) {
 170         sd_bus_message *q;
 171         int r;
 172
 173         assert(i);
 174         assert(m);
 175         assert(reply);
 176
 177         fputs("</node>\n", i->f);
 178
 179         r = fflush_and_check(i->f);
 180         if (r < 0)
 181                 return r;
 182
 183         r = sd_bus_message_new_method_return(m, &q);
 184         if (r < 0)
 185                 return r;
 186
 187         r = sd_bus_message_append(q, "s", i->introspection);
 188         if (r < 0) {
 189                 sd_bus_message_unref(q);
 190                 return r;
 191         }
 192
 193         *reply = q;
 194         return 0;
 195 }
 196
 197 void introspect_free(struct introspect *i) {
 198         assert(i);
 199
 200         safe_fclose(i->f);
 201
 202         free(i->introspection);
 203         zero(*i);
 204 }