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 const char* namespace_flag_to_string(unsigned long flag) {
  29         unsigned i;
  30
  31         flag &= NAMESPACE_FLAGS_ALL;
  32
  33         for (i = 0; namespace_flag_map[i].name; i++)
  34                 if (flag == namespace_flag_map[i].flag)
  35                         return namespace_flag_map[i].name;
  36
  37         return NULL; /* either unknown namespace flag, or a combination of many. This call supports neither. */
  38 }
  39
  40 unsigned long namespace_flag_from_string(const char *name) {
  41         unsigned i;
  42
  43         if (isempty(name))
  44                 return 0;
  45
  46         for (i = 0; namespace_flag_map[i].name; i++)
  47                 if (streq(name, namespace_flag_map[i].name))
  48                         return namespace_flag_map[i].flag;
  49
  50         return 0;
  51 }
  52
  53 int namespace_flag_from_string_many(const char *name, unsigned long *ret) {
  54         unsigned long flags = 0;
  55         int r;
  56
  57         assert_se(ret);
  58
  59         for (;;) {
  60                 _cleanup_free_ char *word = NULL;
  61                 unsigned long f;
  62
  63                 r = extract_first_word(&name, &word, NULL, 0);
  64                 if (r < 0)
  65                         return r;
  66                 if (r == 0)
  67                         break;
  68
  69                 f = namespace_flag_from_string(word);
  70                 if (f == 0)
  71                         return -EINVAL;
  72
  73                 flags |= f;
  74         }
  75
  76         *ret = flags;
  77         return 0;
  78 }
  79
  80 int namespace_flag_to_string_many(unsigned long flags, char **ret) {
  81         _cleanup_free_ char *s = NULL;
  82         unsigned i;
  83
  84         for (i = 0; namespace_flag_map[i].name; i++) {
  85                 if ((flags & namespace_flag_map[i].flag) != namespace_flag_map[i].flag)
  86                         continue;
  87
  88                 if (!s) {
  89                         s = strdup(namespace_flag_map[i].name);
  90                         if (!s)
  91                                 return -ENOMEM;
  92                 } else {
  93                         if (!strextend(&s, " ", namespace_flag_map[i].name, NULL))
  94                                 return -ENOMEM;
  95                 }
  96         }
  97
  98         if (!s) {
  99                 s = strdup("");
 100                 if (!s)
 101                         return -ENOMEM;
 102         }
 103
 104         *ret = TAKE_PTR(s);
 105
 106         return 0;
 107 }