Merge pull request #7469 from kinvolk/dongsu/nspawn-netns

nspawn: introduce an option for specifying network namespace path

src/basic/missing.h

@@ -1271,4 +1271,12 @@ struct fib_rule_uid_range {
 #  define EXT4_IOC_RESIZE_FS              _IOW('f', 16, __u64)
 #endif
 
+#ifndef NSFS_MAGIC
+#define NSFS_MAGIC 0x6e736673
+#endif
+
+#ifndef NS_GET_NSTYPE
+#define NS_GET_NSTYPE _IO(0xb7, 0x3)
+#endif
+
 #include "missing_syscall.h"

src/basic/stat-util.c

@@ -226,6 +226,18 @@ int fd_is_temporary_fs(int fd) {
         return is_temporary_fs(&s);
 }
 
+int fd_is_network_ns(int fd) {
+        int r;
+
+        r = fd_is_fs_type(fd, NSFS_MAGIC);
+        if (r <= 0)
+                return r;
+        r = ioctl(fd, NS_GET_NSTYPE);
+        if (r < 0)
+                return -errno;
+        return r == CLONE_NEWNET;
+}
+
 int path_is_temporary_fs(const char *path) {
         _cleanup_close_ int fd = -1;
 

src/basic/stat-util.h

@@ -62,6 +62,7 @@ int path_is_fs_type(const char *path, statfs_f_type_t magic_value);
 
 bool is_temporary_fs(const struct statfs *s) _pure_;
 int fd_is_temporary_fs(int fd);
+int fd_is_network_ns(int fd);
 int path_is_temporary_fs(const char *path);
 
 /* Because statfs.t_type can be int on some architectures, we have to cast