src/shared/dev-setup.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2010-2012 Lennart Poettering
   6 ***/
   7
   8 #include <errno.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11
  12 #include "alloc-util.h"
  13 #include "dev-setup.h"
  14 #include "label.h"
  15 #include "log.h"
  16 #include "path-util.h"
  17 #include "user-util.h"
  18 #include "util.h"
  19
  20 int dev_setup(const char *prefix, uid_t uid, gid_t gid) {
  21         static const char symlinks[] =
  22                 "-/proc/kcore\0"     "/dev/core\0"
  23                 "/proc/self/fd\0"    "/dev/fd\0"
  24                 "/proc/self/fd/0\0"  "/dev/stdin\0"
  25                 "/proc/self/fd/1\0"  "/dev/stdout\0"
  26                 "/proc/self/fd/2\0"  "/dev/stderr\0";
  27
  28         const char *j, *k;
  29         int r;
  30
  31         NULSTR_FOREACH_PAIR(j, k, symlinks) {
  32                 _cleanup_free_ char *link_name = NULL;
  33                 const char *n;
  34
  35                 if (j[0] == '-') {
  36                         j++;
  37
  38                         if (access(j, F_OK) < 0)
  39                                 continue;
  40                 }
  41
  42                 if (prefix) {
  43                         link_name = prefix_root(prefix, k);
  44                         if (!link_name)
  45                                 return -ENOMEM;
  46
  47                         n = link_name;
  48                 } else
  49                         n = k;
  50
  51                 r = symlink_label(j, n);
  52                 if (r < 0)
  53                         log_debug_errno(r, "Failed to symlink %s to %s: %m", j, n);
  54
  55                 if (uid != UID_INVALID || gid != GID_INVALID)
  56                         if (lchown(n, uid, gid) < 0)
  57                                 log_debug_errno(errno, "Failed to chown %s: %m", n);
  58         }
  59
  60         return 0;
  61 }