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 "bus-internal.h"
  23 #include "bus-util.h"
  24 #include "cgroup-util.h"
  25 #include "conf-parser.h"
  26 #include "dirent-util.h"
  27 #include "fd-util.h"
  28 #include "fileio.h"
  29 #include "mkdir.h"
  30 #include "special.h"
  31 #include "unit-name.h"
  32 #include "util.h"
  33
  34 static const char *arg_dest_late = "/tmp", *arg_dest = "/tmp";
  35
  36 static int create_dbus_files(
  37                 const char *path,
  38                 const char *name,
  39                 const char *service,
  40                 const char *exec,
  41                 const char *user,
  42                 const char *type) {
  43
  44         _cleanup_free_ char *b = NULL, *s = NULL, *lnk = NULL;
  45         _cleanup_fclose_ FILE *f = NULL;
  46         int r;
  47
  48         assert(path);
  49         assert(name);
  50         assert(service || exec);
  51
  52         if (!service) {
  53                 _cleanup_free_ char *a = NULL;
  54
  55                 s = strjoin("dbus-", name, ".service", NULL);
  56                 if (!s)
  57                         return log_oom();
  58
  59                 a = strjoin(arg_dest_late, "/", s, NULL);
  60                 if (!a)
  61                         return log_oom();
  62
  63                 f = fopen(a, "wxe");
  64                 if (!f)
  65                         return log_error_errno(errno, "Failed to create %s: %m", a);
  66
  67                 fprintf(f,
  68                         "# Automatically generated by systemd-dbus1-generator\n\n"
  69                         "[Unit]\n"
  70                         "SourcePath=%s\n"
  71                         "Description=DBUS1: %s\n"
  72                         "Documentation=man:systemd-dbus1-generator(8)\n\n"
  73                         "[Service]\n"
  74                         "ExecStart=%s\n"
  75                         "Type=dbus\n"
  76                         "BusName=%s\n",
  77                         path,
  78                         name,
  79                         exec,
  80                         name);
  81
  82                 if (user)
  83                         fprintf(f, "User=%s\n", user);
  84
  85
  86                 if (type) {
  87                         fprintf(f, "Environment=DBUS_STARTER_BUS_TYPE=%s\n", type);
  88
  89                         if (streq(type, "system"))
  90                                 fprintf(f, "Environment=DBUS_STARTER_ADDRESS=" DEFAULT_SYSTEM_BUS_ADDRESS "\n");
  91                         else if (streq(type, "session")) {
  92                                 char *run;
  93
  94                                 run = getenv("XDG_RUNTIME_DIR");
  95                                 if (!run) {
  96                                         log_error("XDG_RUNTIME_DIR not set.");
  97                                         return -EINVAL;
  98                                 }
  99
 100                                 fprintf(f, "Environment=DBUS_STARTER_ADDRESS="KERNEL_USER_BUS_ADDRESS_FMT ";" UNIX_USER_BUS_ADDRESS_FMT "\n",
 101                                         getuid(), run);
 102                         }
 103                 }
 104
 105                 r = fflush_and_check(f);
 106                 if (r < 0)
 107                         return log_error_errno(r, "Failed to write %s: %m", a);
 108
 109                 f = safe_fclose(f);
 110
 111                 service = s;
 112         }
 113
 114         b = strjoin(arg_dest_late, "/", name, ".busname", NULL);
 115         if (!b)
 116                 return log_oom();
 117
 118         f = fopen(b, "wxe");
 119         if (!f)
 120                 return log_error_errno(errno, "Failed to create %s: %m", b);
 121
 122         fprintf(f,
 123                 "# Automatically generated by systemd-dbus1-generator\n\n"
 124                 "[Unit]\n"
 125                 "SourcePath=%s\n"
 126                 "Description=DBUS1: %s\n"
 127                 "Documentation=man:systemd-dbus1-generator(8)\n\n"
 128                 "[BusName]\n"
 129                 "Name=%s\n"
 130                 "Service=%s\n"
 131                 "AllowWorld=talk\n",
 132                 path,
 133                 name,
 134                 name,
 135                 service);
 136
 137         r = fflush_and_check(f);
 138         if (r < 0)
 139                 return log_error_errno(r, "Failed to write %s: %m", b);
 140
 141         lnk = strjoin(arg_dest_late, "/" SPECIAL_BUSNAMES_TARGET ".wants/", name, ".busname", NULL);
 142         if (!lnk)
 143                 return log_oom();
 144
 145         mkdir_parents_label(lnk, 0755);
 146         if (symlink(b, lnk))
 147                 return log_error_errno(errno, "Failed to create symlink %s: %m", lnk);
 148
 149         return 0;
 150 }
 151
 152 static int add_dbus(const char *path, const char *fname, const char *type) {
 153         _cleanup_free_ char *name = NULL, *exec = NULL, *user = NULL, *service = NULL;
 154
 155         const ConfigTableItem table[] = {
 156                 { "D-BUS Service", "Name", config_parse_string, 0, &name },
 157                 { "D-BUS Service", "Exec", config_parse_string, 0, &exec },
 158                 { "D-BUS Service", "User", config_parse_string, 0, &user },
 159                 { "D-BUS Service", "SystemdService", config_parse_string, 0, &service },
 160                 { },
 161         };
 162
 163         char *p;
 164         int r;
 165
 166         assert(path);
 167         assert(fname);
 168
 169         p = strjoina(path, "/", fname);
 170         r = config_parse(NULL, p, NULL,
 171                          "D-BUS Service\0",
 172                          config_item_table_lookup, table,
 173                          true, false, true, NULL);
 174         if (r < 0)
 175                 return r;
 176
 177         if (!name) {
 178                 log_warning("Activation file %s lacks name setting, ignoring.", p);
 179                 return 0;
 180         }
 181
 182         if (!service_name_is_valid(name)) {
 183                 log_warning("Bus service name %s is not valid, ignoring.", name);
 184                 return 0;
 185         }
 186
 187         if (streq(name, "org.freedesktop.systemd1")) {
 188                 log_debug("Skipping %s, identified as systemd.", p);
 189                 return 0;
 190         }
 191
 192         if (service) {
 193                 if (!unit_name_is_valid(service, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE)) {
 194                         log_warning("Unit name %s is not valid, ignoring.", service);
 195                         return 0;
 196                 }
 197                 if (!endswith(service, ".service")) {
 198                         log_warning("Bus names can only activate services, ignoring %s.", p);
 199                         return 0;
 200                 }
 201         } else {
 202                 if (streq(exec, "/bin/false") || !exec) {
 203                         log_warning("Neither service name nor binary path specified, ignoring %s.", p);
 204                         return 0;
 205                 }
 206
 207                 if (exec[0] != '/') {
 208                         log_warning("Exec= in %s does not start with an absolute path, ignoring.", p);
 209                         return 0;
 210                 }
 211         }
 212
 213         return create_dbus_files(p, name, service, exec, user, type);
 214 }
 215
 216 static int parse_dbus_fragments(const char *path, const char *type) {
 217         _cleanup_closedir_ DIR *d = NULL;
 218         struct dirent *de;
 219         int r;
 220
 221         assert(path);
 222         assert(type);
 223
 224         d = opendir(path);
 225         if (!d) {
 226                 if (errno == -ENOENT)
 227                         return 0;
 228
 229                 log_error_errno(errno, "Failed to enumerate D-Bus activated services: %m");
 230                 return -errno;
 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         log_error_errno(errno, "Failed to read D-Bus services directory: %m");
 249         return -errno;
 250 }
 251
 252 static int link_busnames_target(const char *units) {
 253         const char *f, *t;
 254
 255         f = strjoina(units, "/" SPECIAL_BUSNAMES_TARGET);
 256         t = strjoina(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/" SPECIAL_BUSNAMES_TARGET);
 257
 258         mkdir_parents_label(t, 0755);
 259         if (symlink(f, t) < 0)
 260                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 261
 262         return 0;
 263 }
 264
 265 static int link_compatibility(const char *units) {
 266         const char *f, *t;
 267
 268         f = strjoina(units, "/systemd-bus-proxyd.socket");
 269         t = strjoina(arg_dest, "/" SPECIAL_DBUS_SOCKET);
 270         mkdir_parents_label(t, 0755);
 271         if (symlink(f, t) < 0)
 272                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 273
 274         f = strjoina(units, "/systemd-bus-proxyd.socket");
 275         t = strjoina(arg_dest, "/" SPECIAL_SOCKETS_TARGET ".wants/systemd-bus-proxyd.socket");
 276         mkdir_parents_label(t, 0755);
 277         if (symlink(f, t) < 0)
 278                 return log_error_errno(errno, "Failed to create symlink %s: %m", t);
 279
 280         t = strjoina(arg_dest, "/" SPECIAL_DBUS_SERVICE);
 281         if (symlink("/dev/null", t) < 0)
 282                 return log_error_errno(errno, "Failed to mask %s: %m", t);
 283
 284         return 0;
 285 }
 286
 287 int main(int argc, char *argv[]) {
 288         const char *path, *type, *units;
 289         int r, q;
 290
 291         if (argc > 1 && argc != 4) {
 292                 log_error("This program takes three or no arguments.");
 293                 return EXIT_FAILURE;
 294         }
 295
 296         if (argc > 1) {
 297                 arg_dest = argv[1];
 298                 arg_dest_late = argv[3];
 299         }
 300
 301         log_set_target(LOG_TARGET_SAFE);
 302         log_parse_environment();
 303         log_open();
 304
 305         umask(0022);
 306
 307         if (!is_kdbus_available())
 308                 return 0;
 309
 310         r = cg_pid_get_owner_uid(0, NULL);
 311         if (r >= 0) {
 312                 path = "/usr/share/dbus-1/services";
 313                 type = "session";
 314                 units = USER_DATA_UNIT_PATH;
 315         } else if (r == -ENXIO) {
 316                 path = "/usr/share/dbus-1/system-services";
 317                 type = "system";
 318                 units = SYSTEM_DATA_UNIT_PATH;
 319         } else
 320                 return log_error_errno(r, "Failed to determine whether we are running as user or system instance: %m");
 321
 322         r = parse_dbus_fragments(path, type);
 323
 324         /* FIXME: One day this should just be pulled in statically from basic.target */
 325         q = link_busnames_target(units);
 326         if (q < 0)
 327                 r = q;
 328
 329         q = link_compatibility(units);
 330         if (q < 0)
 331                 r = q;
 332
 333         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 334 }