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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:35:18 +0000 |
commit | b750101eb236130cf056c675997decbac904cc49 (patch) | |
tree | a5df1a06754bdd014cb975c051c83b01c9a97532 /src/basic/devnum-util.h | |
parent | Initial commit. (diff) | |
download | systemd-upstream.tar.xz systemd-upstream.zip |
Adding upstream version 252.22.upstream/252.22upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/basic/devnum-util.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/basic/devnum-util.h b/src/basic/devnum-util.h new file mode 100644 index 0000000..38aa4ef --- /dev/null +++ b/src/basic/devnum-util.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +#pragma once + +#include <inttypes.h> +#include <stdbool.h> +#include <sys/types.h> + +#include "stdio-util.h" + +int parse_devnum(const char *s, dev_t *ret); + +/* glibc and the Linux kernel have different ideas about the major/minor size. These calls will check whether the + * specified major is valid by the Linux kernel's standards, not by glibc's. Linux has 20bits of minor, and 12 bits of + * major space. See MINORBITS in linux/kdev_t.h in the kernel sources. (If you wonder why we define _y here, instead of + * comparing directly >= 0: it's to trick out -Wtype-limits, which would otherwise complain if the type is unsigned, as + * such a test would be pointless in such a case.) */ + +#define DEVICE_MAJOR_VALID(x) \ + ({ \ + typeof(x) _x = (x), _y = 0; \ + _x >= _y && _x < (UINT32_C(1) << 12); \ + \ + }) + +#define DEVICE_MINOR_VALID(x) \ + ({ \ + typeof(x) _x = (x), _y = 0; \ + _x >= _y && _x < (UINT32_C(1) << 20); \ + }) + +int device_path_make_major_minor(mode_t mode, dev_t devnum, char **ret); +int device_path_make_inaccessible(mode_t mode, char **ret); +int device_path_make_canonical(mode_t mode, dev_t devnum, char **ret); +int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devnum); + +static inline bool devnum_set_and_equal(dev_t a, dev_t b) { + /* Returns true if a and b definitely refer to the same device. If either is zero, this means "don't + * know" and we'll return false */ + return a == b && a != 0; +} + +/* Maximum string length for a major:minor string. (Note that DECIMAL_STR_MAX includes space for a trailing NUL) */ +#define DEVNUM_STR_MAX (DECIMAL_STR_MAX(dev_t)-1+1+DECIMAL_STR_MAX(dev_t)) + +#define DEVNUM_FORMAT_STR "%u:%u" +#define DEVNUM_FORMAT_VAL(d) major(d), minor(d) + +static inline char *format_devnum(dev_t d, char buf[static DEVNUM_STR_MAX]) { + return ASSERT_PTR(snprintf_ok(buf, DEVNUM_STR_MAX, DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(d))); +} + +#define FORMAT_DEVNUM(d) format_devnum((d), (char[DEVNUM_STR_MAX]) {}) |