src/shared/nsflags.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2016 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <sched.h>
  21
  22 #include "alloc-util.h"
  23 #include "extract-word.h"
  24 #include "nsflags.h"
  25 #include "string-util.h"
  26
  27 const struct namespace_flag_map namespace_flag_map[] = {
  28         { CLONE_NEWCGROUP, "cgroup" },
  29         { CLONE_NEWIPC,    "ipc"    },
  30         { CLONE_NEWNET,    "net"    },
  31         /* So, the mount namespace flag is called CLONE_NEWNS for historical reasons. Let's expose it here under a more
  32          * explanatory name: "mnt". This is in-line with how the kernel exposes namespaces in /proc/$PID/ns. */
  33         { CLONE_NEWNS,     "mnt"    },
  34         { CLONE_NEWPID,    "pid"    },
  35         { CLONE_NEWUSER,   "user"   },
  36         { CLONE_NEWUTS,    "uts"    },
  37         {}
  38 };
  39
  40 const char* namespace_flag_to_string(unsigned long flag) {
  41         unsigned i;
  42
  43         flag &= NAMESPACE_FLAGS_ALL;
  44
  45         for (i = 0; namespace_flag_map[i].name; i++)
  46                 if (flag == namespace_flag_map[i].flag)
  47                         return namespace_flag_map[i].name;
  48
  49         return NULL; /* either unknown namespace flag, or a combination of many. This call supports neither. */
  50 }
  51
  52 unsigned long namespace_flag_from_string(const char *name) {
  53         unsigned i;
  54
  55         if (isempty(name))
  56                 return 0;
  57
  58         for (i = 0; namespace_flag_map[i].name; i++)
  59                 if (streq(name, namespace_flag_map[i].name))
  60                         return namespace_flag_map[i].flag;
  61
  62         return 0;
  63 }
  64
  65 int namespace_flag_from_string_many(const char *name, unsigned long *ret) {
  66         unsigned long flags = 0;
  67         int r;
  68
  69         assert_se(ret);
  70
  71         for (;;) {
  72                 _cleanup_free_ char *word = NULL;
  73                 unsigned long f;
  74
  75                 r = extract_first_word(&name, &word, NULL, 0);
  76                 if (r < 0)
  77                         return r;
  78                 if (r == 0)
  79                         break;
  80
  81                 f = namespace_flag_from_string(word);
  82                 if (f == 0)
  83                         return -EINVAL;
  84
  85                 flags |= f;
  86         }
  87
  88         *ret = flags;
  89         return 0;
  90 }
  91
  92 int namespace_flag_to_string_many(unsigned long flags, char **ret) {
  93         _cleanup_free_ char *s = NULL;
  94         unsigned i;
  95
  96         for (i = 0; namespace_flag_map[i].name; i++) {
  97                 if ((flags & namespace_flag_map[i].flag) != namespace_flag_map[i].flag)
  98                         continue;
  99
 100                 if (!s) {
 101                         s = strdup(namespace_flag_map[i].name);
 102                         if (!s)
 103                                 return -ENOMEM;
 104                 } else {
 105                         if (!strextend(&s, " ", namespace_flag_map[i].name, NULL))
 106                                 return -ENOMEM;
 107                 }
 108         }
 109
 110         if (!s) {
 111                 s = strdup("");
 112                 if (!s)
 113                         return -ENOMEM;
 114         }
 115
 116         *ret = s;
 117         s = NULL;
 118
 119         return 0;
 120 }