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                 log_error_errno(errno, "Failed to enumerate D-Bus activated services: %m");
 231                 return -errno;
 232         }
 233
 234         r = 0;
 235         FOREACH_DIRENT(de, d, goto fail) {
 236                 int q;
 237
 238                 if (!endswith(de->d_name, ".service"))
 239                         continue;
 240
 241                 q = add_dbus(path, de->d_name, type);
 242                 if (q < 0)
 243                         r = q;
 244         }
 245
 246         return r;
 247
 248 fail:
 249         log_error_errno(errno, "Failed to read D-Bus services directory: %m");
 250         return -errno;
 251 }
 252
 253 static int link_busnames_target(const char *units) {
 254         const char *f, *t;
 255
 256         f = strjoina(units, "/" SPECIAL_BUSNAMES_TARGET);
 257         t = strjoina(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/" SPECIAL_BUSNAMES_TARGET);
 258
 259         mkdir_parents_label(t, 0755);
 260         if (symlink(f, t) < 0)
 261                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 262
 263         return 0;
 264 }
 265
 266 static int link_compatibility(const char *units) {
 267         const char *f, *t;
 268
 269         f = strjoina(units, "/systemd-bus-proxyd.socket");
 270         t = strjoina(arg_dest, "/" SPECIAL_DBUS_SOCKET);
 271         mkdir_parents_label(t, 0755);
 272         if (symlink(f, t) < 0)
 273                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 274
 275         f = strjoina(units, "/systemd-bus-proxyd.socket");
 276         t = strjoina(arg_dest, "/" SPECIAL_SOCKETS_TARGET ".wants/systemd-bus-proxyd.socket");
 277         mkdir_parents_label(t, 0755);
 278         if (symlink(f, t) < 0)
 279                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 280
 281         t = strjoina(arg_dest, "/" SPECIAL_DBUS_SERVICE);
 282         if (symlink("/dev/null", t) < 0)
 283                 return log_error_errno(errno, "Failed to mask %s: %m", t);
 284
 285         return 0;
 286 }
 287
 288 int main(int argc, char *argv[]) {
 289         const char *path, *type, *units;
 290         int r, q;
 291
 292         if (argc > 1 && argc != 4) {
 293                 log_error("This program takes three or no arguments.");
 294                 return EXIT_FAILURE;
 295         }
 296
 297         if (argc > 1) {
 298                 arg_dest = argv[1];
 299                 arg_dest_late = argv[3];
 300         }
 301
 302         log_set_target(LOG_TARGET_SAFE);
 303         log_parse_environment();
 304         log_open();
 305
 306         umask(0022);
 307
 308         if (!is_kdbus_available())
 309                 return 0;
 310
 311         r = cg_pid_get_owner_uid(0, NULL);
 312         if (r >= 0) {
 313                 path = "/usr/share/dbus-1/services";
 314                 type = "session";
 315                 units = USER_DATA_UNIT_PATH;
 316         } else if (r == -ENXIO) {
 317                 path = "/usr/share/dbus-1/system-services";
 318                 type = "system";
 319                 units = SYSTEM_DATA_UNIT_PATH;
 320         } else
 321                 return log_error_errno(r, "Failed to determine whether we are running as user or system instance: %m");
 322
 323         r = parse_dbus_fragments(path, type);
 324
 325         /* FIXME: One day this should just be pulled in statically from basic.target */
 326         q = link_busnames_target(units);
 327         if (q < 0)
 328                 r = q;
 329
 330         q = link_compatibility(units);
 331         if (q < 0)
 332                 r = q;
 333
 334         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 335 }