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
  44         assert(path);
  45         assert(name);
  46         assert(service || exec);
  47
  48         if (!service) {
  49                 _cleanup_free_ char *a = NULL;
  50
  51                 s = strjoin("dbus-", name, ".service", NULL);
  52                 if (!s)
  53                         return log_oom();
  54
  55                 a = strjoin(arg_dest_late, "/", s, NULL);
  56                 if (!a)
  57                         return log_oom();
  58
  59                 f = fopen(a, "wxe");
  60                 if (!f) {
  61                         log_error("Failed to create %s: %m", a);
  62                         return -errno;
  63                 }
  64
  65                 fprintf(f,
  66                         "# Automatically generated by systemd-dbus1-generator\n\n"
  67                         "[Unit]\n"
  68                         "SourcePath=%s\n"
  69                         "Description=DBUS1: %s\n\n"
  70                         "[Service]\n"
  71                         "ExecStart=%s\n"
  72                         "Type=dbus\n"
  73                         "BusName=%s\n",
  74                         path,
  75                         name,
  76                         exec,
  77                         name);
  78
  79                 if (user)
  80                         fprintf(f, "User=%s\n", user);
  81
  82
  83                 if (type) {
  84                         fprintf(f, "Environment=DBUS_STARTER_BUS_TYPE=%s\n", type);
  85
  86                         if (streq(type, "system"))
  87                                 fprintf(f, "Environment=DBUS_STARTER_ADDRESS=kernel:/dev/kdbus/0-system\n");
  88                         else if (streq(type, "session"))
  89                                 fprintf(f, "Environment=DBUS_STARTER_ADDRESS=kernel:/dev/kdbus/%lu-user\n", (unsigned long) getuid());
  90                 }
  91
  92                 fflush(f);
  93                 if (ferror(f)) {
  94                         log_error("Failed to write %s: %m", a);
  95                         return -errno;
  96                 }
  97
  98                 service = s;
  99         }
 100
 101         b = strjoin(arg_dest_late, "/", name, ".busname", NULL);
 102         if (!b)
 103                 return log_oom();
 104
 105         f = fopen(b, "wxe");
 106         if (!f) {
 107                 log_error("Failed to create %s: %m", b);
 108                 return -errno;
 109         }
 110
 111         fprintf(f,
 112                 "# Automatically generated by systemd-dbus1-generator\n\n"
 113                 "[Unit]\n"
 114                 "SourcePath=%s\n"
 115                 "Description=DBUS1: %s\n\n"
 116                 "[BusName]\n"
 117                 "Name=%s\n"
 118                 "Service=%s\n",
 119                 path,
 120                 name,
 121                 name,
 122                 service);
 123
 124         fflush(f);
 125         if (ferror(f)) {
 126                 log_error("Failed to write %s: %m", b);
 127                 return -errno;
 128         }
 129
 130         lnk = strjoin(arg_dest_late, "/" SPECIAL_BUSNAMES_TARGET ".wants/", name, ".busname", NULL);
 131         if (!lnk)
 132                 return log_oom();
 133
 134         mkdir_parents_label(lnk, 0755);
 135         if (symlink(b, lnk)) {
 136                 log_error("Failed to create symlink %s: %m", lnk);
 137                 return -errno;
 138         }
 139
 140         return 0;
 141 }
 142
 143 static int add_dbus(const char *path, const char *fname, const char *type) {
 144         _cleanup_free_ char *name = NULL, *exec = NULL, *user = NULL, *service = NULL;
 145
 146         ConfigTableItem table[] = {
 147                 { "D-BUS Service", "Name", config_parse_string, 0, &name },
 148                 { "D-BUS Service", "Exec", config_parse_string, 0, &exec },
 149                 { "D-BUS Service", "User", config_parse_string, 0, &user },
 150                 { "D-BUS Service", "SystemdService", config_parse_string, 0, &service },
 151         };
 152
 153         _cleanup_fclose_ FILE *f = NULL;
 154         _cleanup_free_ char *p = NULL;
 155         int r;
 156
 157         assert(path);
 158         assert(fname);
 159
 160         p = strjoin(path, "/", fname, NULL);
 161         if (!p)
 162                 return log_oom();
 163
 164         f = fopen(p, "re");
 165         if (!f) {
 166                 if (errno == -ENOENT)
 167                         return 0;
 168
 169                 log_error("Failed to read %s: %m", p);
 170                 return -errno;
 171         }
 172
 173         r = config_parse(NULL, p, f, "D-BUS Service\0", config_item_table_lookup, table, true, false, 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, false)) {
 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("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("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 = strappenda(units, "/" SPECIAL_BUSNAMES_TARGET);
 256         t = strappenda(arg_dest, "/" SPECIAL_BASIC_TARGET ".wants/" SPECIAL_BUSNAMES_TARGET);
 257
 258         mkdir_parents_label(t, 0755);
 259         if (symlink(f, t) < 0) {
 260                 log_error("Failed to create symlink %s: %m", t);
 261                 return -errno;
 262         }
 263
 264         return 0;
 265 }
 266
 267 static int link_compatibility(const char *units) {
 268         const char *f, *t;
 269
 270         f = strappenda(units, "/systemd-bus-proxyd.socket");
 271         t = strappenda(arg_dest, "/" SPECIAL_DBUS_SOCKET);
 272
 273         mkdir_parents_label(t, 0755);
 274         if (symlink(f, t) < 0) {
 275                 log_error("Failed to create symlink %s: %m", t);
 276                 return -errno;
 277         }
 278
 279         t = strappenda(arg_dest, "/" SPECIAL_DBUS_SERVICE);
 280         if (symlink("/dev/null", t) < 0) {
 281                 log_error("Failed to mask %s: %m", t);
 282                 return -errno;
 283         }
 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 (access("/dev/kdbus/control", F_OK) < 0)
 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 == -ENOENT) {
 317                 path = "/usr/share/dbus-1/system-services";
 318                 type = "system";
 319                 units = SYSTEM_DATA_UNIT_PATH;
 320         } else {
 321                 log_error("Failed to determine whether we are running as user or system instance: %s", strerror(-r));
 322                 return r;
 323         }
 324
 325         r = parse_dbus_fragments(path, type);
 326
 327         /* FIXME: One day this should just be pulled in statically from basic.target */
 328         q = link_busnames_target(units);
 329         if (q < 0)
 330                 r = q;
 331
 332         q = link_compatibility(units);
 333         if (q < 0)
 334                 r = q;
 335
 336         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 337 }