src/dbus1-generator/dbus1-generator.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include "alloc-util.h"
  23 #include "bus-internal.h"
  24 #include "bus-util.h"
  25 #include "cgroup-util.h"
  26 #include "conf-parser.h"
  27 #include "dirent-util.h"
  28 #include "fd-util.h"
  29 #include "fileio.h"
  30 #include "mkdir.h"
  31 #include "special.h"
  32 #include "unit-name.h"
  33 #include "util.h"
  34
  35 static const char *arg_dest_late = "/tmp", *arg_dest = "/tmp";
  36
  37 static int create_dbus_files(
  38                 const char *path,
  39                 const char *name,
  40                 const char *service,
  41                 const char *exec,
  42                 const char *user,
  43                 const char *type) {
  44
  45         _cleanup_free_ char *b = NULL, *s = NULL, *lnk = NULL;
  46         _cleanup_fclose_ FILE *f = NULL;
  47         int r;
  48
  49         assert(path);
  50         assert(name);
  51         assert(service || exec);
  52
  53         if (!service) {
  54                 _cleanup_free_ char *a = NULL;
  55
  56                 s = strjoin("dbus-", name, ".service", NULL);
  57                 if (!s)
  58                         return log_oom();
  59
  60                 a = strjoin(arg_dest_late, "/", s, NULL);
  61                 if (!a)
  62                         return log_oom();
  63
  64                 f = fopen(a, "wxe");
  65                 if (!f)
  66                         return log_error_errno(errno, "Failed to create %s: %m", a);
  67
  68                 fprintf(f,
  69                         "# Automatically generated by systemd-dbus1-generator\n\n"
  70                         "[Unit]\n"
  71                         "SourcePath=%s\n"
  72                         "Description=DBUS1: %s\n"
  73                         "Documentation=man:systemd-dbus1-generator(8)\n\n"
  74                         "[Service]\n"
  75                         "ExecStart=%s\n"
  76                         "Type=dbus\n"
  77                         "BusName=%s\n",
  78                         path,
  79                         name,
  80                         exec,
  81                         name);
  82
  83                 if (user)
  84                         fprintf(f, "User=%s\n", user);
  85
  86
  87                 if (type) {
  88                         fprintf(f, "Environment=DBUS_STARTER_BUS_TYPE=%s\n", type);
  89
  90                         if (streq(type, "system"))
  91                                 fprintf(f, "Environment=DBUS_STARTER_ADDRESS=" DEFAULT_SYSTEM_BUS_ADDRESS "\n");
  92                         else if (streq(type, "session")) {
  93                                 char *run;
  94
  95                                 run = getenv("XDG_RUNTIME_DIR");
  96                                 if (!run) {
  97                                         log_error("XDG_RUNTIME_DIR not set.");
  98                                         return -EINVAL;
  99                                 }
 100
 101                                 fprintf(f, "Environment=DBUS_STARTER_ADDRESS="KERNEL_USER_BUS_ADDRESS_FMT ";" UNIX_USER_BUS_ADDRESS_FMT "\n",
 102                                         getuid(), run);
 103                         }
 104                 }
 105
 106                 r = fflush_and_check(f);
 107                 if (r < 0)
 108                         return log_error_errno(r, "Failed to write %s: %m", a);
 109
 110                 f = safe_fclose(f);
 111
 112                 service = s;
 113         }
 114
 115         b = strjoin(arg_dest_late, "/", name, ".busname", NULL);
 116         if (!b)
 117                 return log_oom();
 118
 119         f = fopen(b, "wxe");
 120         if (!f)
 121                 return log_error_errno(errno, "Failed to create %s: %m", b);
 122
 123         fprintf(f,
 124                 "# Automatically generated by systemd-dbus1-generator\n\n"
 125                 "[Unit]\n"
 126                 "SourcePath=%s\n"
 127                 "Description=DBUS1: %s\n"
 128                 "Documentation=man:systemd-dbus1-generator(8)\n\n"
 129                 "[BusName]\n"
 130                 "Name=%s\n"
 131                 "Service=%s\n"
 132                 "AllowWorld=talk\n",
 133                 path,
 134                 name,
 135                 name,
 136                 service);
 137
 138         r = fflush_and_check(f);
 139         if (r < 0)
 140                 return log_error_errno(r, "Failed to write %s: %m", b);
 141
 142         lnk = strjoin(arg_dest_late, "/" SPECIAL_BUSNAMES_TARGET ".wants/", name, ".busname", NULL);
 143         if (!lnk)
 144                 return log_oom();
 145
 146         mkdir_parents_label(lnk, 0755);
 147         if (symlink(b, lnk))
 148                 return log_error_errno(errno, "Failed to create symlink %s: %m", lnk);
 149
 150         return 0;
 151 }
 152
 153 static int add_dbus(const char *path, const char *fname, const char *type) {
 154         _cleanup_free_ char *name = NULL, *exec = NULL, *user = NULL, *service = NULL;
 155
 156         const ConfigTableItem table[] = {
 157                 { "D-BUS Service", "Name", config_parse_string, 0, &name },
 158                 { "D-BUS Service", "Exec", config_parse_string, 0, &exec },
 159                 { "D-BUS Service", "User", config_parse_string, 0, &user },
 160                 { "D-BUS Service", "SystemdService", config_parse_string, 0, &service },
 161                 { },
 162         };
 163
 164         char *p;
 165         int r;
 166
 167         assert(path);
 168         assert(fname);
 169
 170         p = strjoina(path, "/", fname);
 171         r = config_parse(NULL, p, NULL,
 172                          "D-BUS Service\0",
 173                          config_item_table_lookup, table,
 174                          true, false, true, NULL);
 175         if (r < 0)
 176                 return r;
 177
 178         if (!name) {
 179                 log_warning("Activation file %s lacks name setting, ignoring.", p);
 180                 return 0;
 181         }
 182
 183         if (!service_name_is_valid(name)) {
 184                 log_warning("Bus service name %s is not valid, ignoring.", name);
 185                 return 0;
 186         }
 187
 188         if (streq(name, "org.freedesktop.systemd1")) {
 189                 log_debug("Skipping %s, identified as systemd.", p);
 190                 return 0;
 191         }
 192
 193         if (service) {
 194                 if (!unit_name_is_valid(service, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE)) {
 195                         log_warning("Unit name %s is not valid, ignoring.", service);
 196                         return 0;
 197                 }
 198                 if (!endswith(service, ".service")) {
 199                         log_warning("Bus names can only activate services, ignoring %s.", p);
 200                         return 0;
 201                 }
 202         } else {
 203                 if (streq(exec, "/bin/false") || !exec) {
 204                         log_warning("Neither service name nor binary path specified, ignoring %s.", p);
 205                         return 0;
 206                 }
 207
 208                 if (exec[0] != '/') {
 209                         log_warning("Exec= in %s does not start with an absolute path, ignoring.", p);
 210                         return 0;
 211                 }
 212         }
 213
 214         return create_dbus_files(p, name, service, exec, user, type);
 215 }
 216
 217 static int parse_dbus_fragments(const char *path, const char *type) {
 218         _cleanup_closedir_ DIR *d = NULL;
 219         struct dirent *de;
 220         int r;
 221
 222         assert(path);
 223         assert(type);
 224
 225         d = opendir(path);
 226         if (!d) {
 227                 if (errno == -ENOENT)
 228                         return 0;
 229
 230                 return log_error_errno(errno, "Failed to enumerate D-Bus activated services: %m");
 231         }
 232
 233         r = 0;
 234         FOREACH_DIRENT(de, d, goto fail) {
 235                 int q;
 236
 237                 if (!endswith(de->d_name, ".service"))
 238                         continue;
 239
 240                 q = add_dbus(path, de->d_name, type);
 241                 if (q < 0)
 242                         r = q;
 243         }
 244
 245         return r;
 246
 247 fail:
 248         return log_error_errno(errno, "Failed to read D-Bus services directory: %m");
 249 }
 250
 251 static int link_busnames_target(const char *units) {
 252         const char *f, *t;
 253
 254         f = strjoina(units, "/" SPECIAL_BUSNAMES_TARGET);
 255         t = strjoina(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/" SPECIAL_BUSNAMES_TARGET);
 256
 257         mkdir_parents_label(t, 0755);
 258         if (symlink(f, t) < 0)
 259                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 260
 261         return 0;
 262 }
 263
 264 static int link_compatibility(const char *units) {
 265         const char *f, *t;
 266
 267         f = strjoina(units, "/systemd-bus-proxyd.socket");
 268         t = strjoina(arg_dest, "/" SPECIAL_DBUS_SOCKET);
 269         mkdir_parents_label(t, 0755);
 270         if (symlink(f, t) < 0)
 271                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 272
 273         f = strjoina(units, "/systemd-bus-proxyd.socket");
 274         t = strjoina(arg_dest, "/" SPECIAL_SOCKETS_TARGET ".wants/systemd-bus-proxyd.socket");
 275         mkdir_parents_label(t, 0755);
 276         if (symlink(f, t) < 0)
 277                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 278
 279         t = strjoina(arg_dest, "/" SPECIAL_DBUS_SERVICE);
 280         if (symlink("/dev/null", t) < 0)
 281                 return log_error_errno(errno, "Failed to mask %s: %m", t);
 282
 283         return 0;
 284 }
 285
 286 int main(int argc, char *argv[]) {
 287         const char *path, *type, *units;
 288         int r, q;
 289
 290         if (argc > 1 && argc != 4) {
 291                 log_error("This program takes three or no arguments.");
 292                 return EXIT_FAILURE;
 293         }
 294
 295         if (argc > 1) {
 296                 arg_dest = argv[1];
 297                 arg_dest_late = argv[3];
 298         }
 299
 300         log_set_target(LOG_TARGET_SAFE);
 301         log_parse_environment();
 302         log_open();
 303
 304         umask(0022);
 305
 306         if (!is_kdbus_available())
 307                 return 0;
 308
 309         r = cg_pid_get_owner_uid(0, NULL);
 310         if (r >= 0) {
 311                 path = "/usr/share/dbus-1/services";
 312                 type = "session";
 313                 units = USER_DATA_UNIT_PATH;
 314         } else if (r == -ENXIO) {
 315                 path = "/usr/share/dbus-1/system-services";
 316                 type = "system";
 317                 units = SYSTEM_DATA_UNIT_PATH;
 318         } else
 319                 return log_error_errno(r, "Failed to determine whether we are running as user or system instance: %m");
 320
 321         r = parse_dbus_fragments(path, type);
 322
 323         /* FIXME: One day this should just be pulled in statically from basic.target */
 324         q = link_busnames_target(units);
 325         if (q < 0)
 326                 r = q;
 327
 328         q = link_compatibility(units);
 329         if (q < 0)
 330                 r = q;
 331
 332         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 333 }