src/shared/nsflags.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2016 Lennart Poettering
   6 ***/
   7
   8 #include <sched.h>
   9
  10 #include "alloc-util.h"
  11 #include "extract-word.h"
  12 #include "nsflags.h"
  13 #include "string-util.h"
  14
  15 const struct namespace_flag_map namespace_flag_map[] = {
  16         { CLONE_NEWCGROUP, "cgroup" },
  17         { CLONE_NEWIPC,    "ipc"    },
  18         { CLONE_NEWNET,    "net"    },
  19         /* So, the mount namespace flag is called CLONE_NEWNS for historical reasons. Let's expose it here under a more
  20          * explanatory name: "mnt". This is in-line with how the kernel exposes namespaces in /proc/$PID/ns. */
  21         { CLONE_NEWNS,     "mnt"    },
  22         { CLONE_NEWPID,    "pid"    },
  23         { CLONE_NEWUSER,   "user"   },
  24         { CLONE_NEWUTS,    "uts"    },
  25         {}
  26 };
  27
  28 int namespace_flags_from_string(const char *name, unsigned long *ret) {
  29         unsigned long flags = 0;
  30         int r;
  31
  32         assert_se(ret);
  33
  34         for (;;) {
  35                 _cleanup_free_ char *word = NULL;
  36                 unsigned long f = 0;
  37                 unsigned i;
  38
  39                 r = extract_first_word(&name, &word, NULL, 0);
  40                 if (r < 0)
  41                         return r;
  42                 if (r == 0)
  43                         break;
  44
  45                 for (i = 0; namespace_flag_map[i].name; i++)
  46                         if (streq(word, namespace_flag_map[i].name)) {
  47                                  f = namespace_flag_map[i].flag;
  48                                  break;
  49                         }
  50
  51                 if (f == 0)
  52                         return -EINVAL;
  53
  54                 flags |= f;
  55         }
  56
  57         *ret = flags;
  58         return 0;
  59 }
  60
  61 int namespace_flags_to_string(unsigned long flags, char **ret) {
  62         _cleanup_free_ char *s = NULL;
  63         unsigned i;
  64
  65         for (i = 0; namespace_flag_map[i].name; i++) {
  66                 if ((flags & namespace_flag_map[i].flag) != namespace_flag_map[i].flag)
  67                         continue;
  68
  69                 if (!strextend_with_separator(&s, " ", namespace_flag_map[i].name, NULL))
  70                         return -ENOMEM;
  71         }
  72
  73         if (!s) {
  74                 s = strdup("");
  75                 if (!s)
  76                         return -ENOMEM;
  77         }
  78
  79         *ret = TAKE_PTR(s);
  80
  81         return 0;
  82 }