src/dbus1-generator/dbus1-generator.c

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