src/login/uaccess.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <string.h>
  24
  25 #include <systemd/sd-daemon.h>
  26 #include <systemd/sd-login.h>
  27
  28 #include "logind-acl.h"
  29 #include "util.h"
  30 #include "log.h"
  31
  32 int main(int argc, char *argv[]) {
  33         int r;
  34         const char *path = NULL, *seat;
  35         bool changed_acl = false;
  36         uid_t uid;
  37
  38         log_set_target(LOG_TARGET_AUTO);
  39         log_parse_environment();
  40         log_open();
  41
  42         umask(0022);
  43
  44         if (argc < 2 || argc > 3) {
  45                 log_error("This program expects one or two arguments.");
  46                 r = -EINVAL;
  47                 goto finish;
  48         }
  49
  50         /* Make sure we don't muck around with ACLs the system is not
  51          * running systemd. */
  52         if (!sd_booted())
  53                 return 0;
  54
  55         path = argv[1];
  56         seat = argc < 3 || isempty(argv[2]) ? "seat0" : argv[2];
  57
  58         r = sd_seat_get_active(seat, NULL, &uid);
  59         if (r == -ENOENT) {
  60                 /* No active session on this seat */
  61                 r = 0;
  62                 goto finish;
  63         } else if (r < 0) {
  64                 log_error("Failed to determine active user on seat %s.", seat);
  65                 goto finish;
  66         }
  67
  68         r = devnode_acl(path, true, false, 0, true, uid);
  69         if (r < 0) {
  70                 log_error("Failed to apply ACL on %s: %s", path, strerror(-r));
  71                 goto finish;
  72         }
  73
  74         changed_acl = true;
  75         r = 0;
  76
  77 finish:
  78         if (path && !changed_acl) {
  79                 int k;
  80                 /* Better be safe that sorry and reset ACL */
  81
  82                 k = devnode_acl(path, true, false, 0, false, 0);
  83                 if (k < 0) {
  84                         log_error("Failed to apply ACL on %s: %s", path, strerror(-k));
  85                         if (r >= 0)
  86                                 r = k;
  87                 }
  88         }
  89
  90         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
  91 }