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-objects.h"
   8 #include "bus-protocol.h"
   9 #include "bus-signature.h"
  10 #include "fd-util.h"
  11 #include "fileio.h"
  12 #include "memory-util.h"
  13 #include "string-util.h"
  14
  15 int introspect_begin(struct introspect *i, bool trusted) {
  16         assert(i);
  17
  18         zero(*i);
  19         i->trusted = trusted;
  20
  21         i->f = open_memstream(&i->introspection, &i->size);
  22         if (!i->f)
  23                 return -ENOMEM;
  24
  25         (void) __fsetlocking(i->f, FSETLOCKING_BYCALLER);
  26
  27         fputs(BUS_INTROSPECT_DOCTYPE
  28               "<node>\n", i->f);
  29
  30         return 0;
  31 }
  32
  33 int introspect_write_default_interfaces(struct introspect *i, bool object_manager) {
  34         assert(i);
  35
  36         fputs(BUS_INTROSPECT_INTERFACE_PEER
  37               BUS_INTROSPECT_INTERFACE_INTROSPECTABLE
  38               BUS_INTROSPECT_INTERFACE_PROPERTIES, i->f);
  39
  40         if (object_manager)
  41                 fputs(BUS_INTROSPECT_INTERFACE_OBJECT_MANAGER, i->f);
  42
  43         return 0;
  44 }
  45
  46 int introspect_write_child_nodes(struct introspect *i, Set *s, const char *prefix) {
  47         char *node;
  48
  49         assert(i);
  50         assert(prefix);
  51
  52         while ((node = set_steal_first(s))) {
  53                 const char *e;
  54
  55                 e = object_path_startswith(node, prefix);
  56                 if (e && e[0])
  57                         fprintf(i->f, " <node name=\"%s\"/>\n", e);
  58
  59                 free(node);
  60         }
  61
  62         return 0;
  63 }
  64
  65 static void introspect_write_flags(struct introspect *i, int type, uint64_t flags) {
  66         if (flags & SD_BUS_VTABLE_DEPRECATED)
  67                 fputs("   <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
  68
  69         if (type == _SD_BUS_VTABLE_METHOD && (flags & SD_BUS_VTABLE_METHOD_NO_REPLY))
  70                 fputs("   <annotation name=\"org.freedesktop.DBus.Method.NoReply\" value=\"true\"/>\n", i->f);
  71
  72         if (IN_SET(type, _SD_BUS_VTABLE_PROPERTY, _SD_BUS_VTABLE_WRITABLE_PROPERTY)) {
  73                 if (flags & SD_BUS_VTABLE_PROPERTY_EXPLICIT)
  74                         fputs("   <annotation name=\"org.freedesktop.systemd1.Explicit\" value=\"true\"/>\n", i->f);
  75
  76                 if (flags & SD_BUS_VTABLE_PROPERTY_CONST)
  77                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"const\"/>\n", i->f);
  78                 else if (flags & SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION)
  79                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"invalidates\"/>\n", i->f);
  80                 else if (!(flags & SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE))
  81                         fputs("   <annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>\n", i->f);
  82         }
  83
  84         if (!i->trusted &&
  85             IN_SET(type, _SD_BUS_VTABLE_METHOD, _SD_BUS_VTABLE_WRITABLE_PROPERTY) &&
  86             !(flags & SD_BUS_VTABLE_UNPRIVILEGED))
  87                 fputs("   <annotation name=\"org.freedesktop.systemd1.Privileged\" value=\"true\"/>\n", i->f);
  88 }
  89
  90 /* Note that "names" is both an input and an output parameter. It initially points to the first argument name in a
  91    NULL-separated list of strings, and is then advanced with each argument, and the resulting pointer is returned. */
  92 static int introspect_write_arguments(struct introspect *i, const char *signature, const char **names, 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 (**names != '\0') {
 108                         fprintf(i->f, " name=\"%s\"", *names);
 109                         *names += strlen(*names) + 1;
 110                 }
 111
 112                 if (direction)
 113                         fprintf(i->f, " direction=\"%s\"/>\n", direction);
 114                 else
 115                         fputs("/>\n", i->f);
 116
 117                 signature += l;
 118         }
 119 }
 120
 121 int introspect_write_interface(struct introspect *i, const sd_bus_vtable *v) {
 122         const sd_bus_vtable *vtable = v;
 123         const char *names = "";
 124
 125         assert(i);
 126         assert(v);
 127
 128         for (; v->type != _SD_BUS_VTABLE_END; v = bus_vtable_next(vtable, v)) {
 129
 130                 /* Ignore methods, signals and properties that are
 131                  * marked "hidden", but do show the interface
 132                  * itself */
 133
 134                 if (v->type != _SD_BUS_VTABLE_START && (v->flags & SD_BUS_VTABLE_HIDDEN))
 135                         continue;
 136
 137                 switch (v->type) {
 138
 139                 case _SD_BUS_VTABLE_START:
 140                         if (v->flags & SD_BUS_VTABLE_DEPRECATED)
 141                                 fputs("  <annotation name=\"org.freedesktop.DBus.Deprecated\" value=\"true\"/>\n", i->f);
 142                         break;
 143
 144                 case _SD_BUS_VTABLE_METHOD:
 145                         fprintf(i->f, "  <method name=\"%s\">\n", v->x.method.member);
 146                         if (bus_vtable_has_names(vtable))
 147                                 names = strempty(v->x.method.names);
 148                         introspect_write_arguments(i, strempty(v->x.method.signature), &names, "in");
 149                         introspect_write_arguments(i, strempty(v->x.method.result), &names, "out");
 150                         introspect_write_flags(i, v->type, v->flags);
 151                         fputs("  </method>\n", i->f);
 152                         break;
 153
 154                 case _SD_BUS_VTABLE_PROPERTY:
 155                 case _SD_BUS_VTABLE_WRITABLE_PROPERTY:
 156                         fprintf(i->f, "  <property name=\"%s\" type=\"%s\" access=\"%s\">\n",
 157                                 v->x.property.member,
 158                                 v->x.property.signature,
 159                                 v->type == _SD_BUS_VTABLE_WRITABLE_PROPERTY ? "readwrite" : "read");
 160                         introspect_write_flags(i, v->type, v->flags);
 161                         fputs("  </property>\n", i->f);
 162                         break;
 163
 164                 case _SD_BUS_VTABLE_SIGNAL:
 165                         fprintf(i->f, "  <signal name=\"%s\">\n", v->x.signal.member);
 166                         if (bus_vtable_has_names(vtable))
 167                                 names = strempty(v->x.method.names);
 168                         introspect_write_arguments(i, strempty(v->x.signal.signature), &names, NULL);
 169                         introspect_write_flags(i, v->type, v->flags);
 170                         fputs("  </signal>\n", i->f);
 171                         break;
 172                 }
 173
 174         }
 175
 176         return 0;
 177 }
 178
 179 int introspect_finish(struct introspect *i, sd_bus *bus, sd_bus_message *m, sd_bus_message **reply) {
 180         sd_bus_message *q;
 181         int r;
 182
 183         assert(i);
 184         assert(m);
 185         assert(reply);
 186
 187         fputs("</node>\n", i->f);
 188
 189         r = fflush_and_check(i->f);
 190         if (r < 0)
 191                 return r;
 192
 193         r = sd_bus_message_new_method_return(m, &q);
 194         if (r < 0)
 195                 return r;
 196
 197         r = sd_bus_message_append(q, "s", i->introspection);
 198         if (r < 0) {
 199                 sd_bus_message_unref(q);
 200                 return r;
 201         }
 202
 203         *reply = q;
 204         return 0;
 205 }
 206
 207 void introspect_free(struct introspect *i) {
 208         assert(i);
 209
 210         safe_fclose(i->f);
 211
 212         free(i->introspection);
 213         zero(*i);
 214 }