src/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 "logind-acl.h"
  26 #include "util.h"
  27 #include "log.h"
  28
  29 int main(int argc, char *argv[]) {
  30         int r;
  31         const char *path = NULL, *seat;
  32         char *p, *active_uid = NULL;
  33         unsigned long ul;
  34         bool changed_acl = false;
  35
  36         log_set_target(LOG_TARGET_AUTO);
  37         log_parse_environment();
  38         log_open();
  39
  40         if (argc < 2 || argc > 3) {
  41                 log_error("This program expects one or two arguments.");
  42                 r = -EINVAL;
  43                 goto finish;
  44         }
  45
  46         path = argv[1];
  47         seat = argc < 3 || isempty(argv[2]) ? "seat0" : argv[2];
  48
  49         p = strappend("/run/systemd/seats/", seat);
  50         if (!p) {
  51                 log_error("Out of memory.");
  52                 r = -ENOMEM;
  53                 goto finish;
  54         }
  55
  56         r = parse_env_file(p, NEWLINE,
  57                            "ACTIVE_UID", &active_uid,
  58                            NULL);
  59         free(p);
  60
  61         if (r < 0) {
  62                 if (errno == ENOENT) {
  63                         r = 0;
  64                         goto finish;
  65                 }
  66
  67                 log_error("Failed to read seat data for %s: %s", seat, strerror(-r));
  68                 goto finish;
  69         }
  70
  71         if (active_uid) {
  72                 r = safe_atolu(active_uid, &ul);
  73                 if (r < 0) {
  74                         log_error("Failed to parse active UID value %s: %s", active_uid, strerror(-r));
  75                         goto finish;
  76                 }
  77
  78                 r = devnode_acl(path, true, false, 0, true, (uid_t) ul);
  79                 if (r < 0) {
  80                         log_error("Failed to apply ACL on %s: %s", path, strerror(-r));
  81                         goto finish;
  82                 }
  83
  84                 changed_acl = true;
  85         }
  86
  87         r = 0;
  88
  89 finish:
  90         if (path && !changed_acl) {
  91                 int k;
  92                 /* Better be safe that sorry and reset ACL */
  93
  94                 k = devnode_acl(path, true, false, 0, false, 0);
  95                 if (k < 0) {
  96                         log_error("Failed to apply ACL on %s: %s", path, strerror(-k));
  97                         if (r >= 0)
  98                                 r = k;
  99                 }
 100         }
 101
 102         free(active_uid);
 103
 104         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 105 }