src/shared/dev-setup.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010-2012 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 <errno.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25
  26 #include "alloc-util.h"
  27 #include "dev-setup.h"
  28 #include "label.h"
  29 #include "path-util.h"
  30 #include "user-util.h"
  31 #include "util.h"
  32
  33 int dev_setup(const char *prefix, uid_t uid, gid_t gid) {
  34         static const char symlinks[] =
  35                 "-/proc/kcore\0"     "/dev/core\0"
  36                 "/proc/self/fd\0"    "/dev/fd\0"
  37                 "/proc/self/fd/0\0"  "/dev/stdin\0"
  38                 "/proc/self/fd/1\0"  "/dev/stdout\0"
  39                 "/proc/self/fd/2\0"  "/dev/stderr\0";
  40
  41         const char *j, *k;
  42         int r;
  43
  44         NULSTR_FOREACH_PAIR(j, k, symlinks) {
  45                 _cleanup_free_ char *link_name = NULL;
  46                 const char *n;
  47
  48                 if (j[0] == '-') {
  49                         j++;
  50
  51                         if (access(j, F_OK) < 0)
  52                                 continue;
  53                 }
  54
  55                 if (prefix) {
  56                         link_name = prefix_root(prefix, k);
  57                         if (!link_name)
  58                                 return -ENOMEM;
  59
  60                         n = link_name;
  61                 } else
  62                         n = k;
  63
  64                 r = symlink_label(j, n);
  65                 if (r < 0)
  66                         log_debug_errno(r, "Failed to symlink %s to %s: %m", j, n);
  67
  68                 if (uid != UID_INVALID || gid != GID_INVALID)
  69                         if (lchown(n, uid, gid) < 0)
  70                                 log_debug_errno(errno, "Failed to chown %s: %m", n);
  71         }
  72
  73         return 0;
  74 }