SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

basic: split out dev_t related calls into new devno-util.[ch]

Browse Source 
No actual code changes, just splitting out of some dev_t handling
related calls from stat-util.[ch], they are quite a number already, and
deserve their own module now I think.

Also, try to settle on the name "devnum" as the name for the concept,
instead of "devno" or "dev" or "devid". "devnum" is the name exported in
udev APIs, hence probably best to stick to that. (this just renames a
few symbols to "devum", local variables are left untouched, to make the
patch not too invasive)

No actual code changes.
This commit is contained in:
Lennart Poettering
2022-04-13 16:26:31 +02:00
parent c87c307806
commit 7176f06c9e
39 changed files with 329 additions and 288 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/devnum-util.c
+133
View File
@@ -0,0 +1,133 @@
/* 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 (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/%u:%u", t, major(devnum), minor(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
+37
View File
@@ -0,0 +1,37 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <inttypes.h>
#include <stdbool.h>
#include <sys/types.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;
}
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"