1 files changed, 77 insertions, 0 deletions
diff --git a/src/shared/nsflags.c b/src/shared/nsflags.c
new file mode 100644
index 0000000..8cc2d08
--- /dev/null
+++ b/src/shared/nsflags.c
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+
+#include "alloc-util.h"
+#include "extract-word.h"
+#include "nsflags.h"
+#include "string-util.h"
+
+const struct namespace_flag_map namespace_flag_map[] = {
+        { CLONE_NEWCGROUP, "cgroup" },
+        { CLONE_NEWIPC,    "ipc"    },
+        { CLONE_NEWNET,    "net"    },
+        /* So, the mount namespace flag is called CLONE_NEWNS for historical reasons. Let's expose it here under a more
+         * explanatory name: "mnt". This is in-line with how the kernel exposes namespaces in /proc/$PID/ns. */
+        { CLONE_NEWNS,     "mnt"    },
+        { CLONE_NEWPID,    "pid"    },
+        { CLONE_NEWUSER,   "user"   },
+        { CLONE_NEWUTS,    "uts"    },
+        {}
+};
+
+int namespace_flags_from_string(const char *name, unsigned long *ret) {
+        unsigned long flags = 0;
+        int r;
+
+        assert_se(ret);
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL;
+                unsigned long f = 0;
+                unsigned i;
+
+                r = extract_first_word(&name, &word, NULL, 0);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                for (i = 0; namespace_flag_map[i].name; i++)
+                        if (streq(word, namespace_flag_map[i].name)) {
+                                 f = namespace_flag_map[i].flag;
+                                 break;
+                        }
+
+                if (f == 0)
+                        return -EINVAL;
+
+                flags |= f;
+        }
+
+        *ret = flags;
+        return 0;
+}
+
+int namespace_flags_to_string(unsigned long flags, char **ret) {
+        _cleanup_free_ char *s = NULL;
+        unsigned i;
+
+        for (i = 0; namespace_flag_map[i].name; i++) {
+                if ((flags & namespace_flag_map[i].flag) != namespace_flag_map[i].flag)
+                        continue;
+
+                if (!strextend_with_separator(&s, " ", namespace_flag_map[i].name, NULL))
+                        return -ENOMEM;
+        }
+
+        if (!s) {
+                s = strdup("");
+                if (!s)
+                        return -ENOMEM;
+        }
+
+        *ret = TAKE_PTR(s);
+
+        return 0;
+}