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Merge pull request #23070 from poettering/devnum-split

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basic: some devnum handling tweaks and refactorings
This commit is contained in:
Yu Watanabe
2022-04-14 03:45:39 +09:00
committed by GitHub
parent f4e357d77f 02b9047edf
commit bd1f75d5fb
41 changed files with 380 additions and 312 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/devnum-util.c
+135
View File
@@ -0,0 +1,135 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <string.h>
#include <sys/stat.h>
#include "chase-symlinks.h"
#include "devnum-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "string-util.h"
int parse_devnum(const char *s, dev_t *ret) {
const char *major;
unsigned x, y;
size_t n;
int r;
n = strspn(s, DIGITS);
if (n == 0)
return -EINVAL;
if (n > DECIMAL_STR_MAX(dev_t))
return -EINVAL;
if (s[n] != ':')
return -EINVAL;
major = strndupa_safe(s, n);
r = safe_atou(major, &x);
if (r < 0)
return r;
r = safe_atou(s + n + 1, &y);
if (r < 0)
return r;
if (!DEVICE_MAJOR_VALID(x) || !DEVICE_MINOR_VALID(y))
return -ERANGE;
*ret = makedev(x, y);
return 0;
}
int device_path_make_major_minor(mode_t mode, dev_t devnum, char **ret) {
const char *t;
/* Generates the /dev/{char|block}/MAJOR:MINOR path for a dev_t */
if (S_ISCHR(mode))
t = "char";
else if (S_ISBLK(mode))
t = "block";
else
return -ENODEV;
if (asprintf(ret, "/dev/%s/" DEVNUM_FORMAT_STR, t, DEVNUM_FORMAT_VAL(devnum)) < 0)
return -ENOMEM;
return 0;
}
int device_path_make_canonical(mode_t mode, dev_t devnum, char **ret) {
_cleanup_free_ char *p = NULL;
int r;
/* Finds the canonical path for a device, i.e. resolves the /dev/{char|block}/MAJOR:MINOR path to the end. */
assert(ret);
if (major(devnum) == 0 && minor(devnum) == 0) {
char *s;
/* A special hack to make sure our 'inaccessible' device nodes work. They won't have symlinks in
* /dev/block/ and /dev/char/, hence we handle them specially here. */
if (S_ISCHR(mode))
s = strdup("/run/systemd/inaccessible/chr");
else if (S_ISBLK(mode))
s = strdup("/run/systemd/inaccessible/blk");
else
return -ENODEV;
if (!s)
return -ENOMEM;
*ret = s;
return 0;
}
r = device_path_make_major_minor(mode, devnum, &p);
if (r < 0)
return r;
return chase_symlinks(p, NULL, 0, ret, NULL);
}
int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devnum) {
mode_t mode;
dev_t devnum;
int r;
/* Tries to extract the major/minor directly from the device path if we can. Handles /dev/block/ and /dev/char/
* paths, as well out synthetic inaccessible device nodes. Never goes to disk. Returns -ENODEV if the device
* path cannot be parsed like this. */
if (path_equal(path, "/run/systemd/inaccessible/chr")) {
mode = S_IFCHR;
devnum = makedev(0, 0);
} else if (path_equal(path, "/run/systemd/inaccessible/blk")) {
mode = S_IFBLK;
devnum = makedev(0, 0);
} else {
const char *w;
w = path_startswith(path, "/dev/block/");
if (w)
mode = S_IFBLK;
else {
w = path_startswith(path, "/dev/char/");
if (!w)
return -ENODEV;
mode = S_IFCHR;
}
r = parse_devnum(w, &devnum);
if (r < 0)
return r;
}
if (ret_mode)
*ret_mode = mode;
if (ret_devnum)
*ret_devnum = devnum;
return 0;
}
src/basic/devnum-util.h
+51
View File
@@ -0,0 +1,51 @@
/* 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_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]) {})
src/basic/meson.build
+2
View File
@@ -32,6 +32,8 @@ basic_sources = files(
'conf-files.c',
'conf-files.h',
'def.h',
'devnum-util.c',
'devnum-util.h',
'dirent-util.c',
'dirent-util.h',
'dns-def.h',
src/basic/parse-util.c
-28
View File
@@ -692,34 +692,6 @@ int parse_ip_prefix_length(const char *s, int *ret) {
return 0;
}
int parse_dev(const char *s, dev_t *ret) {
const char *major;
unsigned x, y;
size_t n;
int r;
n = strspn(s, DIGITS);
if (n == 0)
return -EINVAL;
if (s[n] != ':')
return -EINVAL;
major = strndupa_safe(s, n);
r = safe_atou(major, &x);
if (r < 0)
return r;
r = safe_atou(s + n + 1, &y);
if (r < 0)
return r;
if (!DEVICE_MAJOR_VALID(x) || !DEVICE_MINOR_VALID(y))
return -ERANGE;
*ret = makedev(x, y);
return 0;
}
int parse_oom_score_adjust(const char *s, int *ret) {
int r, v;
src/basic/parse-util.h
-1
View File
@@ -12,7 +12,6 @@
typedef unsigned long loadavg_t;
int parse_boolean(const char *v) _pure_;
int parse_dev(const char *s, dev_t *ret);
int parse_pid(const char *s, pid_t* ret_pid);
int parse_mode(const char *s, mode_t *ret);
int parse_ifindex(const char *s);
src/basic/stat-util.c
-95
View File
@@ -314,101 +314,6 @@ int fd_verify_directory(int fd) {
return stat_verify_directory(&st);
}
int device_path_make_major_minor(mode_t mode, dev_t devno, char **ret) {
const char *t;
/* Generates the /dev/{char|block}/MAJOR:MINOR path for a dev_t */
if (S_ISCHR(mode))
t = "char";
else if (S_ISBLK(mode))
t = "block";
else
return -ENODEV;
if (asprintf(ret, "/dev/%s/%u:%u", t, major(devno), minor(devno)) < 0)
return -ENOMEM;
return 0;
}
int device_path_make_canonical(mode_t mode, dev_t devno, char **ret) {
_cleanup_free_ char *p = NULL;
int r;
/* Finds the canonical path for a device, i.e. resolves the /dev/{char|block}/MAJOR:MINOR path to the end. */
assert(ret);
if (major(devno) == 0 && minor(devno) == 0) {
char *s;
/* A special hack to make sure our 'inaccessible' device nodes work. They won't have symlinks in
* /dev/block/ and /dev/char/, hence we handle them specially here. */
if (S_ISCHR(mode))
s = strdup("/run/systemd/inaccessible/chr");
else if (S_ISBLK(mode))
s = strdup("/run/systemd/inaccessible/blk");
else
return -ENODEV;
if (!s)
return -ENOMEM;
*ret = s;
return 0;
}
r = device_path_make_major_minor(mode, devno, &p);
if (r < 0)
return r;
return chase_symlinks(p, NULL, 0, ret, NULL);
}
int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devno) {
mode_t mode;
dev_t devno;
int r;
/* Tries to extract the major/minor directly from the device path if we can. Handles /dev/block/ and /dev/char/
* paths, as well out synthetic inaccessible device nodes. Never goes to disk. Returns -ENODEV if the device
* path cannot be parsed like this. */
if (path_equal(path, "/run/systemd/inaccessible/chr")) {
mode = S_IFCHR;
devno = makedev(0, 0);
} else if (path_equal(path, "/run/systemd/inaccessible/blk")) {
mode = S_IFBLK;
devno = makedev(0, 0);
} else {
const char *w;
w = path_startswith(path, "/dev/block/");
if (w)
mode = S_IFBLK;
else {
w = path_startswith(path, "/dev/char/");
if (!w)
return -ENODEV;
mode = S_IFCHR;
}
r = parse_dev(w, &devno);
if (r < 0)
return r;
}
if (ret_mode)
*ret_mode = mode;
if (ret_devno)
*ret_devno = devno;
return 0;
}
int proc_mounted(void) {
int r;
src/basic/stat-util.h
-29
View File
@@ -71,29 +71,6 @@ int fd_verify_regular(int fd);
int stat_verify_directory(const struct stat *st);
int fd_verify_directory(int fd);
/* 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 devno, char **ret);
int device_path_make_canonical(mode_t mode, dev_t devno, char **ret);
int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devno);
int proc_mounted(void);
bool stat_inode_same(const struct stat *a, const struct stat *b);
@@ -119,9 +96,3 @@ int statx_fallback(int dfd, const char *path, int flags, unsigned mask, struct s
struct new_statx nsx; \
} var
#endif
static inline bool devid_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;
}
src/basic/terminal-util.c
+1
View File
@@ -22,6 +22,7 @@
#include "alloc-util.h"
#include "def.h"
#include "devnum-util.h"
#include "env-util.h"
#include "fd-util.h"
#include "fileio.h"