846b3bd61e
device_path_make_{major_minor|canonical) generate device node paths given a mode_t and a dev_t. We have similar code all over the place, let's unify this in one place. The former will generate a "/dev/char/" or "/dev/block" path, and never go to disk. The latter then goes to disk and resolves that path to the actual path of the device node. device_path_parse_major_minor() reverses device_path_make_major_minor(), also withozut going to disk. We have similar code doing something like this at various places, let's unify this in a single set of functions. This also allows us to teach them special tricks, for example handling of the /run/systemd/inaccessible/{blk|chr} device nodes, which we use for masking device nodes, and which do not exist in /dev/char/* and /dev/block/*
88 lines
3.2 KiB
C
88 lines
3.2 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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#include <stdbool.h>
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#include <stddef.h>
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#include <sys/stat.h>
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#include <sys/statfs.h>
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#include <sys/types.h>
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#include <sys/vfs.h>
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#include "macro.h"
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int is_symlink(const char *path);
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int is_dir(const char *path, bool follow);
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int is_dir_fd(int fd);
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int is_device_node(const char *path);
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int dir_is_empty(const char *path);
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static inline int dir_is_populated(const char *path) {
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int r;
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r = dir_is_empty(path);
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if (r < 0)
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return r;
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return !r;
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}
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bool null_or_empty(struct stat *st) _pure_;
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int null_or_empty_path(const char *fn);
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int null_or_empty_fd(int fd);
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int path_is_read_only_fs(const char *path);
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int files_same(const char *filea, const char *fileb, int flags);
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/* The .f_type field of struct statfs is really weird defined on
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* different archs. Let's give its type a name. */
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typedef typeof(((struct statfs*)NULL)->f_type) statfs_f_type_t;
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bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) _pure_;
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int fd_is_fs_type(int fd, statfs_f_type_t magic_value);
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int path_is_fs_type(const char *path, statfs_f_type_t magic_value);
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bool is_temporary_fs(const struct statfs *s) _pure_;
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bool is_network_fs(const struct statfs *s) _pure_;
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int fd_is_temporary_fs(int fd);
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int fd_is_network_fs(int fd);
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int fd_is_network_ns(int fd);
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int path_is_temporary_fs(const char *path);
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/* Because statfs.t_type can be int on some architectures, we have to cast
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* the const magic to the type, otherwise the compiler warns about
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* signed/unsigned comparison, because the magic can be 32 bit unsigned.
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*/
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#define F_TYPE_EQUAL(a, b) (a == (typeof(a)) b)
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int stat_verify_regular(const struct stat *st);
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int fd_verify_regular(int fd);
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int stat_verify_directory(const struct stat *st);
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int fd_verify_directory(int fd);
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/* glibc and the Linux kernel have different ideas about the major/minor size. These calls will check whether the
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* specified major is valid by the Linux kernel's standards, not by glibc's. Linux has 20bits of minor, and 12 bits of
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* major space. See MINORBITS in linux/kdev_t.h in the kernel sources. (If you wonder why we define _y here, instead of
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* comparing directly >= 0: it's to trick out -Wtype-limits, which would otherwise complain if the type is unsigned, as
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* such a test would be pointless in such a case.) */
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#define DEVICE_MAJOR_VALID(x) \
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({ \
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typeof(x) _x = (x), _y = 0; \
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_x >= _y && _x < (UINT32_C(1) << 12); \
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\
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})
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#define DEVICE_MINOR_VALID(x) \
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({ \
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typeof(x) _x = (x), _y = 0; \
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_x >= _y && _x < (UINT32_C(1) << 20); \
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})
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int device_path_make_major_minor(mode_t mode, dev_t devno, char **ret);
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int device_path_make_canonical(mode_t mode, dev_t devno, char **ret);
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int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devno);
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