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

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