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 "seccomp-util.h"
  26 #include "string-util.h"
  27
  28 const struct namespace_flag_map namespace_flag_map[] = {
  29         { CLONE_NEWCGROUP, "cgroup" },
  30         { CLONE_NEWIPC,    "ipc"    },
  31         { CLONE_NEWNET,    "net"    },
  32         /* So, the mount namespace flag is called CLONE_NEWNS for historical reasons. Let's expose it here under a more
  33          * explanatory name: "mnt". This is in-line with how the kernel exposes namespaces in /proc/$PID/ns. */
  34         { CLONE_NEWNS,     "mnt"    },
  35         { CLONE_NEWPID,    "pid"    },
  36         { CLONE_NEWUSER,   "user"   },
  37         { CLONE_NEWUTS,    "uts"    },
  38         {}
  39 };
  40
  41 const char* namespace_flag_to_string(unsigned long flag) {
  42         unsigned i;
  43
  44         flag &= NAMESPACE_FLAGS_ALL;
  45
  46         for (i = 0; namespace_flag_map[i].name; i++)
  47                 if (flag == namespace_flag_map[i].flag)
  48                         return namespace_flag_map[i].name;
  49
  50         return NULL; /* either unknown namespace flag, or a combination of many. This call supports neither. */
  51 }
  52
  53 unsigned long namespace_flag_from_string(const char *name) {
  54         unsigned i;
  55
  56         if (isempty(name))
  57                 return 0;
  58
  59         for (i = 0; namespace_flag_map[i].name; i++)
  60                 if (streq(name, namespace_flag_map[i].name))
  61                         return namespace_flag_map[i].flag;
  62
  63         return 0;
  64 }
  65
  66 int namespace_flag_from_string_many(const char *name, unsigned long *ret) {
  67         unsigned long flags = 0;
  68         int r;
  69
  70         assert_se(ret);
  71
  72         for (;;) {
  73                 _cleanup_free_ char *word = NULL;
  74                 unsigned long f;
  75
  76                 r = extract_first_word(&name, &word, NULL, 0);
  77                 if (r < 0)
  78                         return r;
  79                 if (r == 0)
  80                         break;
  81
  82                 f = namespace_flag_from_string(word);
  83                 if (f == 0)
  84                         return -EINVAL;
  85
  86                 flags |= f;
  87         }
  88
  89         *ret = flags;
  90         return 0;
  91 }
  92
  93 int namespace_flag_to_string_many(unsigned long flags, char **ret) {
  94         _cleanup_free_ char *s = NULL;
  95         unsigned i;
  96
  97         for (i = 0; namespace_flag_map[i].name; i++) {
  98                 if ((flags & namespace_flag_map[i].flag) != namespace_flag_map[i].flag)
  99                         continue;
 100
 101                 if (!s) {
 102                         s = strdup(namespace_flag_map[i].name);
 103                         if (!s)
 104                                 return -ENOMEM;
 105                 } else {
 106                         if (!strextend(&s, " ", namespace_flag_map[i].name, NULL))
 107                                 return -ENOMEM;
 108                 }
 109         }
 110
 111         if (!s) {
 112                 s = strdup("");
 113                 if (!s)
 114                         return -ENOMEM;
 115         }
 116
 117         *ret = s;
 118         s = NULL;
 119
 120         return 0;
 121 }