src/basic/stat-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include <stdbool.h>
   5 #include <stddef.h>
   6 #include <sys/stat.h>
   7 #include <sys/statfs.h>
   8 #include <sys/types.h>
   9 #include <sys/vfs.h>
  10
  11 #include "macro.h"
  12
  13 int is_symlink(const char *path);
  14 int is_dir(const char *path, bool follow);
  15 int is_dir_fd(int fd);
  16 int is_device_node(const char *path);
  17
  18 int dir_is_empty_at(int dir_fd, const char *path);
  19 static inline int dir_is_empty(const char *path) {
  20         return dir_is_empty_at(AT_FDCWD, path);
  21 }
  22
  23 static inline int dir_is_populated(const char *path) {
  24         int r;
  25         r = dir_is_empty(path);
  26         if (r < 0)
  27                 return r;
  28         return !r;
  29 }
  30
  31 bool null_or_empty(struct stat *st) _pure_;
  32 int null_or_empty_path(const char *fn);
  33 int null_or_empty_fd(int fd);
  34
  35 int path_is_read_only_fs(const char *path);
  36
  37 int files_same(const char *filea, const char *fileb, int flags);
  38
  39 /* The .f_type field of struct statfs is really weird defined on
  40  * different archs. Let's give its type a name. */
  41 typedef typeof(((struct statfs*)NULL)->f_type) statfs_f_type_t;
  42
  43 bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) _pure_;
  44 int fd_is_fs_type(int fd, statfs_f_type_t magic_value);
  45 int path_is_fs_type(const char *path, statfs_f_type_t magic_value);
  46
  47 bool is_temporary_fs(const struct statfs *s) _pure_;
  48 bool is_network_fs(const struct statfs *s) _pure_;
  49
  50 int fd_is_temporary_fs(int fd);
  51 int fd_is_network_fs(int fd);
  52
  53 int fd_is_network_ns(int fd);
  54
  55 int path_is_temporary_fs(const char *path);
  56
  57 /* Because statfs.t_type can be int on some architectures, we have to cast
  58  * the const magic to the type, otherwise the compiler warns about
  59  * signed/unsigned comparison, because the magic can be 32 bit unsigned.
  60  */
  61 #define F_TYPE_EQUAL(a, b) (a == (typeof(a)) b)
  62
  63 int stat_verify_regular(const struct stat *st);
  64 int fd_verify_regular(int fd);
  65
  66 int stat_verify_directory(const struct stat *st);
  67 int fd_verify_directory(int fd);
  68
  69 /* glibc and the Linux kernel have different ideas about the major/minor size. These calls will check whether the
  70  * specified major is valid by the Linux kernel's standards, not by glibc's. Linux has 20bits of minor, and 12 bits of
  71  * major space. See MINORBITS in linux/kdev_t.h in the kernel sources. (If you wonder why we define _y here, instead of
  72  * comparing directly >= 0: it's to trick out -Wtype-limits, which would otherwise complain if the type is unsigned, as
  73  * such a test would be pointless in such a case.) */
  74
  75 #define DEVICE_MAJOR_VALID(x)                                           \
  76         ({                                                              \
  77                 typeof(x) _x = (x), _y = 0;                             \
  78                 _x >= _y && _x < (UINT32_C(1) << 12);                   \
  79                                                                         \
  80         })
  81
  82 #define DEVICE_MINOR_VALID(x)                                           \
  83         ({                                                              \
  84                 typeof(x) _x = (x), _y = 0;                             \
  85                 _x >= _y && _x < (UINT32_C(1) << 20);                   \
  86         })
  87
  88 int device_path_make_major_minor(mode_t mode, dev_t devno, char **ret);
  89 int device_path_make_canonical(mode_t mode, dev_t devno, char **ret);
  90 int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devno);