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 "util.h"
  23 #include "conf-parser.h"
  24 #include "special.h"
  25 #include "mkdir.h"
  26 #include "bus-util.h"
  27 #include "bus-internal.h"
  28 #include "unit-name.h"
  29 #include "cgroup-util.h"
  30
  31 static const char *arg_dest_late = "/tmp", *arg_dest = "/tmp";
  32
  33 static int create_dbus_files(
  34                 const char *path,
  35                 const char *name,
  36                 const char *service,
  37                 const char *exec,
  38                 const char *user,
  39                 const char *type) {
  40
  41         _cleanup_free_ char *b = NULL, *s = NULL, *lnk = NULL;
  42         _cleanup_fclose_ FILE *f = NULL;
  43         int r;
  44
  45         assert(path);
  46         assert(name);
  47         assert(service || exec);
  48
  49         if (!service) {
  50                 _cleanup_free_ char *a = NULL;
  51
  52                 s = strjoin("dbus-", name, ".service", NULL);
  53                 if (!s)
  54                         return log_oom();
  55
  56                 a = strjoin(arg_dest_late, "/", s, NULL);
  57                 if (!a)
  58                         return log_oom();
  59
  60                 f = fopen(a, "wxe");
  61                 if (!f) {
  62                         log_error_errno(errno, "Failed to create %s: %m", a);
  63                         return -errno;
  64                 }
  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                 fclose(f);
 109                 f = NULL;
 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                 log_error_errno(errno, "Failed to create %s: %m", b);
 121                 return -errno;
 122         }
 123
 124         fprintf(f,
 125                 "# Automatically generated by systemd-dbus1-generator\n\n"
 126                 "[Unit]\n"
 127                 "SourcePath=%s\n"
 128                 "Description=DBUS1: %s\n"
 129                 "Documentation=man:systemd-dbus1-generator(8)\n\n"
 130                 "[BusName]\n"
 131                 "Name=%s\n"
 132                 "Service=%s\n"
 133                 "AllowWorld=talk\n",
 134                 path,
 135                 name,
 136                 name,
 137                 service);
 138
 139         r = fflush_and_check(f);
 140         if (r < 0)
 141                 return log_error_errno(r, "Failed to write %s: %m", b);
 142
 143         lnk = strjoin(arg_dest_late, "/" SPECIAL_BUSNAMES_TARGET ".wants/", name, ".busname", NULL);
 144         if (!lnk)
 145                 return log_oom();
 146
 147         mkdir_parents_label(lnk, 0755);
 148         if (symlink(b, lnk)) {
 149                 log_error_errno(errno, "Failed to create symlink %s: %m", lnk);
 150                 return -errno;
 151         }
 152
 153         return 0;
 154 }
 155
 156 static int add_dbus(const char *path, const char *fname, const char *type) {
 157         _cleanup_free_ char *name = NULL, *exec = NULL, *user = NULL, *service = NULL;
 158
 159         const ConfigTableItem table[] = {
 160                 { "D-BUS Service", "Name", config_parse_string, 0, &name },
 161                 { "D-BUS Service", "Exec", config_parse_string, 0, &exec },
 162                 { "D-BUS Service", "User", config_parse_string, 0, &user },
 163                 { "D-BUS Service", "SystemdService", config_parse_string, 0, &service },
 164         };
 165
 166         char *p;
 167         int r;
 168
 169         assert(path);
 170         assert(fname);
 171
 172         p = strappenda(path, "/", fname);
 173         r = config_parse(NULL, p, NULL,
 174                          "D-BUS Service\0",
 175                          config_item_table_lookup, table,
 176                          true, false, true, NULL);
 177         if (r < 0)
 178                 return r;
 179
 180         if (!name) {
 181                 log_warning("Activation file %s lacks name setting, ignoring.", p);
 182                 return 0;
 183         }
 184
 185         if (!service_name_is_valid(name)) {
 186                 log_warning("Bus service name %s is not valid, ignoring.", name);
 187                 return 0;
 188         }
 189
 190         if (streq(name, "org.freedesktop.systemd1")) {
 191                 log_debug("Skipping %s, identified as systemd.", p);
 192                 return 0;
 193         }
 194
 195         if (service) {
 196                 if (!unit_name_is_valid(service, TEMPLATE_INVALID)) {
 197                         log_warning("Unit name %s is not valid, ignoring.", service);
 198                         return 0;
 199                 }
 200                 if (!endswith(service, ".service")) {
 201                         log_warning("Bus names can only activate services, ignoring %s.", p);
 202                         return 0;
 203                 }
 204         } else {
 205                 if (streq(exec, "/bin/false") || !exec) {
 206                         log_warning("Neither service name nor binary path specified, ignoring %s.", p);
 207                         return 0;
 208                 }
 209
 210                 if (exec[0] != '/') {
 211                         log_warning("Exec= in %s does not start with an absolute path, ignoring.", p);
 212                         return 0;
 213                 }
 214         }
 215
 216         return create_dbus_files(p, name, service, exec, user, type);
 217 }
 218
 219 static int parse_dbus_fragments(const char *path, const char *type) {
 220         _cleanup_closedir_ DIR *d = NULL;
 221         struct dirent *de;
 222         int r;
 223
 224         assert(path);
 225         assert(type);
 226
 227         d = opendir(path);
 228         if (!d) {
 229                 if (errno == -ENOENT)
 230                         return 0;
 231
 232                 log_error_errno(errno, "Failed to enumerate D-Bus activated services: %m");
 233                 return -errno;
 234         }
 235
 236         r = 0;
 237         FOREACH_DIRENT(de, d, goto fail) {
 238                 int q;
 239
 240                 if (!endswith(de->d_name, ".service"))
 241                         continue;
 242
 243                 q = add_dbus(path, de->d_name, type);
 244                 if (q < 0)
 245                         r = q;
 246         }
 247
 248         return r;
 249
 250 fail:
 251         log_error_errno(errno, "Failed to read D-Bus services directory: %m");
 252         return -errno;
 253 }
 254
 255 static int link_busnames_target(const char *units) {
 256         const char *f, *t;
 257
 258         f = strappenda(units, "/" SPECIAL_BUSNAMES_TARGET);
 259         t = strappenda(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/" SPECIAL_BUSNAMES_TARGET);
 260
 261         mkdir_parents_label(t, 0755);
 262         if (symlink(f, t) < 0) {
 263                 log_error_errno(errno, "Failed to create symlink %s: %m", t);
 264                 return -errno;
 265         }
 266
 267         return 0;
 268 }
 269
 270 static int link_compatibility(const char *units) {
 271         const char *f, *t;
 272
 273         f = strappenda(units, "/systemd-bus-proxyd.socket");
 274         t = strappenda(arg_dest, "/" SPECIAL_DBUS_SOCKET);
 275         mkdir_parents_label(t, 0755);
 276         if (symlink(f, t) < 0) {
 277                 log_error_errno(errno, "Failed to create symlink %s: %m", t);
 278                 return -errno;
 279         }
 280
 281         f = strappenda(units, "/systemd-bus-proxyd.socket");
 282         t = strappenda(arg_dest, "/" SPECIAL_SOCKETS_TARGET ".wants/systemd-bus-proxyd.socket");
 283         mkdir_parents_label(t, 0755);
 284         if (symlink(f, t) < 0) {
 285                 log_error_errno(errno, "Failed to create symlink %s: %m", t);
 286                 return -errno;
 287         }
 288
 289         t = strappenda(arg_dest, "/" SPECIAL_DBUS_SERVICE);
 290         if (symlink("/dev/null", t) < 0) {
 291                 log_error_errno(errno, "Failed to mask %s: %m", t);
 292                 return -errno;
 293         }
 294
 295         return 0;
 296 }
 297
 298 int main(int argc, char *argv[]) {
 299         const char *path, *type, *units;
 300         int r, q;
 301
 302         if (argc > 1 && argc != 4) {
 303                 log_error("This program takes three or no arguments.");
 304                 return EXIT_FAILURE;
 305         }
 306
 307         if (argc > 1) {
 308                 arg_dest = argv[1];
 309                 arg_dest_late = argv[3];
 310         }
 311
 312         log_set_target(LOG_TARGET_SAFE);
 313         log_parse_environment();
 314         log_open();
 315
 316         umask(0022);
 317
 318         if (access("/sys/fs/kdbus/control", F_OK) < 0)
 319                 return 0;
 320
 321         r = cg_pid_get_owner_uid(0, NULL);
 322         if (r >= 0) {
 323                 path = "/usr/share/dbus-1/services";
 324                 type = "session";
 325                 units = USER_DATA_UNIT_PATH;
 326         } else if (r == -ENOENT) {
 327                 path = "/usr/share/dbus-1/system-services";
 328                 type = "system";
 329                 units = SYSTEM_DATA_UNIT_PATH;
 330         } else
 331                 return log_error_errno(r, "Failed to determine whether we are running as user or system instance: %m");
 332
 333         r = parse_dbus_fragments(path, type);
 334
 335         /* FIXME: One day this should just be pulled in statically from basic.target */
 336         q = link_busnames_target(units);
 337         if (q < 0)
 338                 r = q;
 339
 340         q = link_compatibility(units);
 341         if (q < 0)
 342                 r = q;
 343
 344         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 345 }