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Add a little helper to make /sys/dev/block/major:minor paths

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This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2017-11-30 12:59:23 +01:00
parent ee3467c6bd
commit 553e15f21b
4 changed files with 34 additions and 46 deletions
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src/basic/util.c
+16 -37
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@@ -39,6 +39,7 @@
#include "build.h"
#include "cgroup-util.h"
#include "def.h"
#include "device-nodes.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
@@ -118,63 +119,42 @@ int socket_from_display(const char *display, char **path) {
}
int block_get_whole_disk(dev_t d, dev_t *ret) {
char *p, *s;
char p[SYS_BLOCK_PATH_MAX("/partition")];
_cleanup_free_ char *s = NULL;
int r;
unsigned n, m;
assert(ret);
/* If it has a queue this is good enough for us */
if (asprintf(&p, "/sys/dev/block/%u:%u/queue", major(d), minor(d)) < 0)
return -ENOMEM;
r = access(p, F_OK);
free(p);
if (r >= 0) {
xsprintf_sys_block_path(p, "/queue", d);
if (access(p, F_OK) >= 0) {
*ret = d;
return 0;
}
/* If it is a partition find the originating device */
if (asprintf(&p, "/sys/dev/block/%u:%u/partition", major(d), minor(d)) < 0)
return -ENOMEM;
r = access(p, F_OK);
free(p);
if (r < 0)
xsprintf_sys_block_path(p, "/partition", d);
if (access(p, F_OK) < 0)
return -ENOENT;
/* Get parent dev_t */
if (asprintf(&p, "/sys/dev/block/%u:%u/../dev", major(d), minor(d)) < 0)
return -ENOMEM;
xsprintf_sys_block_path(p, "/../dev", d);
r = read_one_line_file(p, &s);
free(p);
if (r < 0)
return r;
r = sscanf(s, "%u:%u", &m, &n);
free(s);
if (r != 2)
return -EINVAL;
/* Only return this if it is really good enough for us. */
if (asprintf(&p, "/sys/dev/block/%u:%u/queue", m, n) < 0)
return -ENOMEM;
xsprintf_sys_block_path(p, "/queue", makedev(m, n));
if (access(p, F_OK) < 0)
return -ENOENT;
r = access(p, F_OK);
free(p);
if (r >= 0) {
*ret = makedev(m, n);
return 0;
}
return -ENOENT;
*ret = makedev(m, n);
return 0;
}
bool kexec_loaded(void) {
@@ -749,7 +729,8 @@ int get_block_device(const char *path, dev_t *dev) {
int get_block_device_harder(const char *path, dev_t *dev) {
_cleanup_closedir_ DIR *d = NULL;
_cleanup_free_ char *p = NULL, *t = NULL;
_cleanup_free_ char *t = NULL;
char p[SYS_BLOCK_PATH_MAX("/slaves")];
struct dirent *de, *found = NULL;
const char *q;
unsigned maj, min;
@@ -767,9 +748,7 @@ int get_block_device_harder(const char *path, dev_t *dev) {
if (r <= 0)
return r;
if (asprintf(&p, "/sys/dev/block/%u:%u/slaves", major(dt), minor(dt)) < 0)
return -ENOMEM;
xsprintf_sys_block_path(p, "/slaves", dt);
d = opendir(p);
if (!d) {
if (errno == ENOENT)