648 lines
13 KiB
C
648 lines
13 KiB
C
/*
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* Copyright (C) 2011 Karel Zak <kzak@redhat.com>
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*/
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#include <ctype.h>
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#include "c.h"
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#include "at.h"
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#include "pathnames.h"
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#include "sysfs.h"
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char *sysfs_devno_attribute_path(dev_t devno, char *buf,
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size_t bufsiz, const char *attr)
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{
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int len;
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if (attr)
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len = snprintf(buf, bufsiz, _PATH_SYS_DEVBLOCK "/%d:%d/%s",
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major(devno), minor(devno), attr);
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else
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len = snprintf(buf, bufsiz, _PATH_SYS_DEVBLOCK "/%d:%d",
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major(devno), minor(devno));
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return (len < 0 || (size_t) len + 1 > bufsiz) ? NULL : buf;
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}
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int sysfs_devno_has_attribute(dev_t devno, const char *attr)
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{
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char path[PATH_MAX];
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struct stat info;
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if (!sysfs_devno_attribute_path(devno, path, sizeof(path), attr))
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return 0;
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if (stat(path, &info) == 0)
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return 1;
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return 0;
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}
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char *sysfs_devno_path(dev_t devno, char *buf, size_t bufsiz)
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{
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return sysfs_devno_attribute_path(devno, buf, bufsiz, NULL);
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}
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dev_t sysfs_devname_to_devno(const char *name, const char *parent)
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{
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char buf[PATH_MAX], *path = NULL;
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dev_t dev = 0;
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if (strncmp("/dev/", name, 5) == 0) {
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/*
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* Read from /dev
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*/
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struct stat st;
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if (stat(name, &st) == 0)
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dev = st.st_rdev;
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else
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name += 5; /* unaccesible, or not node in /dev */
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}
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if (!dev && parent) {
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/*
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* Create path to /sys/block/<parent>/<name>/dev
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*/
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int len = snprintf(buf, sizeof(buf),
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_PATH_SYS_BLOCK "/%s/%s/dev", parent, name);
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if (len < 0 || (size_t) len + 1 > sizeof(buf))
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return 0;
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path = buf;
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} else if (!dev) {
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/*
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* Create path to /sys/block/<name>/dev
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*/
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int len = snprintf(buf, sizeof(buf),
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_PATH_SYS_BLOCK "/%s/dev", name);
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if (len < 0 || (size_t) len + 1 > sizeof(buf))
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return 0;
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path = buf;
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}
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if (path) {
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/*
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* read devno from sysfs
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*/
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FILE *f;
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int maj = 0, min = 0;
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f = fopen(path, "r");
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if (!f)
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return 0;
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if (fscanf(f, "%u:%u", &maj, &min) == 2)
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dev = makedev(maj, min);
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fclose(f);
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}
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return dev;
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}
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/*
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* Returns devname (e.g. "/dev/sda1") for the given devno.
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*
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* Note that the @buf has to be large enough to store /sys/dev/block/<maj:min>
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* symlinks.
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*
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* Please, use more robust blkid_devno_to_devname() in your applications.
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*/
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char *sysfs_devno_to_devpath(dev_t devno, char *buf, size_t bufsiz)
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{
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struct sysfs_cxt cxt;
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char *name;
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size_t sz;
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struct stat st;
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if (sysfs_init(&cxt, devno, NULL))
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return NULL;
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name = sysfs_get_devname(&cxt, buf, bufsiz);
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sysfs_deinit(&cxt);
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if (!name)
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return NULL;
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sz = strlen(name);
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if (sz + sizeof("/dev/") > bufsiz)
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return NULL;
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/* create the final "/dev/<name>" string */
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memmove(buf + 5, name, sz + 1);
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memcpy(buf, "/dev/", 5);
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if (!stat(buf, &st) && S_ISBLK(st.st_mode) && st.st_rdev == devno)
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return buf;
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return NULL;
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}
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int sysfs_init(struct sysfs_cxt *cxt, dev_t devno, struct sysfs_cxt *parent)
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{
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char path[PATH_MAX];
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int fd, rc;
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memset(cxt, 0, sizeof(*cxt));
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cxt->dir_fd = -1;
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if (!sysfs_devno_path(devno, path, sizeof(path)))
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goto err;
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fd = open(path, O_RDONLY);
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if (fd < 0)
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goto err;
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cxt->dir_fd = fd;
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cxt->dir_path = strdup(path);
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if (!cxt->dir_path)
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goto err;
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cxt->devno = devno;
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cxt->parent = parent;
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return 0;
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err:
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rc = errno > 0 ? -errno : -1;
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sysfs_deinit(cxt);
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return rc;
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}
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void sysfs_deinit(struct sysfs_cxt *cxt)
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{
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if (!cxt)
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return;
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if (cxt->dir_fd >= 0)
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close(cxt->dir_fd);
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free(cxt->dir_path);
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cxt->devno = 0;
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cxt->dir_fd = -1;
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cxt->parent = NULL;
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cxt->dir_path = NULL;
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}
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int sysfs_stat(struct sysfs_cxt *cxt, const char *attr, struct stat *st)
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{
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int rc = fstat_at(cxt->dir_fd, cxt->dir_path, attr, st, 0);
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if (rc != 0 && errno == ENOENT &&
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strncmp(attr, "queue/", 6) == 0 && cxt->parent) {
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/* Exception for "queue/<attr>". These attributes are available
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* for parental devices only
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*/
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return fstat_at(cxt->parent->dir_fd,
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cxt->parent->dir_path, attr, st, 0);
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}
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return rc;
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}
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int sysfs_has_attribute(struct sysfs_cxt *cxt, const char *attr)
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{
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struct stat st;
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return sysfs_stat(cxt, attr, &st) == 0;
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}
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static int sysfs_open(struct sysfs_cxt *cxt, const char *attr)
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{
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int fd = open_at(cxt->dir_fd, cxt->dir_path, attr, O_RDONLY);
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if (fd == -1 && errno == ENOENT &&
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strncmp(attr, "queue/", 6) == 0 && cxt->parent) {
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/* Exception for "queue/<attr>". These attributes are available
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* for parental devices only
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*/
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fd = open_at(cxt->parent->dir_fd, cxt->dir_path, attr, O_RDONLY);
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}
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return fd;
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}
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ssize_t sysfs_readlink(struct sysfs_cxt *cxt, const char *attr,
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char *buf, size_t bufsiz)
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{
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if (attr)
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return readlink_at(cxt->dir_fd, cxt->dir_path, attr, buf, bufsiz);
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/* read /sys/dev/block/<maj:min> link */
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return readlink(cxt->dir_path, buf, bufsiz);
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}
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DIR *sysfs_opendir(struct sysfs_cxt *cxt, const char *attr)
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{
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DIR *dir;
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int fd;
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if (attr)
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fd = sysfs_open(cxt, attr);
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else
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/* request to open root of device in sysfs (/sys/block/<dev>)
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* -- we cannot use cxt->sysfs_fd directly, because closedir()
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* will close this our persistent file descriptor.
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*/
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fd = dup(cxt->dir_fd);
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if (fd < 0)
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return NULL;
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dir = fdopendir(fd);
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if (!dir) {
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close(fd);
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return NULL;
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}
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if (!attr)
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rewinddir(dir);
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return dir;
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}
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static FILE *sysfs_fopen(struct sysfs_cxt *cxt, const char *attr)
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{
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int fd = sysfs_open(cxt, attr);
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return fd < 0 ? NULL : fdopen(fd, "r");
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}
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static struct dirent *xreaddir(DIR *dp)
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{
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struct dirent *d;
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while ((d = readdir(dp))) {
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if (!strcmp(d->d_name, ".") ||
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!strcmp(d->d_name, ".."))
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continue;
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/* blacklist here? */
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break;
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}
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return d;
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}
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int sysfs_is_partition_dirent(DIR *dir, struct dirent *d, const char *parent_name)
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{
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char path[256];
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#ifdef _DIRENT_HAVE_D_TYPE
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if (d->d_type != DT_DIR &&
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d->d_type != DT_LNK)
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return 0;
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#endif
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if (parent_name) {
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const char *p = parent_name;
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size_t len;
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/* /dev/sda --> "sda" */
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if (*parent_name == '/') {
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p = strrchr(parent_name, '/');
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if (!p)
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return 0;
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p++;
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}
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len = strlen(p);
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if (strlen(d->d_name) <= len)
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return 0;
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/* partitions subdir name is "<parent>[:digit:]" */
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return strncmp(p, d->d_name, len) == 0
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&& isdigit(*(d->d_name + len));
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}
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/* Cannot use /partition file, not supported on old sysfs */
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snprintf(path, sizeof(path), "%s/start", d->d_name);
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return faccessat(dirfd(dir), path, R_OK, 0) == 0;
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}
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int sysfs_scanf(struct sysfs_cxt *cxt, const char *attr, const char *fmt, ...)
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{
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FILE *f = sysfs_fopen(cxt, attr);
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va_list ap;
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int rc;
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if (!f)
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return -EINVAL;
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va_start(ap, fmt);
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rc = vfscanf(f, fmt, ap);
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va_end(ap);
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fclose(f);
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return rc;
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}
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int sysfs_read_s64(struct sysfs_cxt *cxt, const char *attr, int64_t *res)
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{
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int64_t x = 0;
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if (sysfs_scanf(cxt, attr, "%"SCNd64, &x) == 1) {
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if (res)
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*res = x;
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return 0;
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}
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return -1;
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}
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int sysfs_read_u64(struct sysfs_cxt *cxt, const char *attr, uint64_t *res)
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{
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uint64_t x = 0;
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if (sysfs_scanf(cxt, attr, "%"SCNu64, &x) == 1) {
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if (res)
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*res = x;
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return 0;
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}
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return -1;
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}
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int sysfs_read_int(struct sysfs_cxt *cxt, const char *attr, int *res)
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{
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int x = 0;
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if (sysfs_scanf(cxt, attr, "%d", &x) == 1) {
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if (res)
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*res = x;
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return 0;
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}
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return -1;
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}
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char *sysfs_strdup(struct sysfs_cxt *cxt, const char *attr)
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{
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char buf[1024];
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return sysfs_scanf(cxt, attr, "%1024[^\n]", buf) == 1 ?
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strdup(buf) : NULL;
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}
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int sysfs_count_dirents(struct sysfs_cxt *cxt, const char *attr)
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{
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DIR *dir;
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int r = 0;
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if (!(dir = sysfs_opendir(cxt, attr)))
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return 0;
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while (xreaddir(dir)) r++;
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closedir(dir);
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return r;
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}
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int sysfs_count_partitions(struct sysfs_cxt *cxt, const char *devname)
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{
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DIR *dir;
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struct dirent *d;
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int r = 0;
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if (!(dir = sysfs_opendir(cxt, NULL)))
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return 0;
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while ((d = xreaddir(dir))) {
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if (sysfs_is_partition_dirent(dir, d, devname))
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r++;
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}
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closedir(dir);
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return r;
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}
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/*
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* Returns slave name if there is only one slave, otherwise returns NULL.
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* The result should be deallocated by free().
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*/
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char *sysfs_get_slave(struct sysfs_cxt *cxt)
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{
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DIR *dir;
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struct dirent *d;
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char *name = NULL;
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if (!(dir = sysfs_opendir(cxt, "slaves")))
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return NULL;
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while ((d = xreaddir(dir))) {
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if (name)
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goto err; /* more slaves */
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name = strdup(d->d_name);
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}
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closedir(dir);
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return name;
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err:
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free(name);
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closedir(dir);
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return NULL;
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}
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/*
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* Note that the @buf has to be large enough to store /sys/dev/block/<maj:min>
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* symlinks.
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*/
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char *sysfs_get_devname(struct sysfs_cxt *cxt, char *buf, size_t bufsiz)
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{
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char *name = NULL;
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ssize_t sz;
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sz = sysfs_readlink(cxt, NULL, buf, bufsiz - 1);
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if (sz < 0)
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return NULL;
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buf[sz] = '\0';
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name = strrchr(buf, '/');
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if (!name)
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return NULL;
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name++;
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sz = strlen(name);
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memmove(buf, name, sz + 1);
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return buf;
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}
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/* returns basename and keeps dirname in the @path */
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static char *stripoff_last_component(char *path)
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{
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char *p = strrchr(path, '/');
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if (!p)
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return NULL;
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*p = '\0';
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return ++p;
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}
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static int get_dm_wholedisk(struct sysfs_cxt *cxt, char *diskname,
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size_t len, dev_t *diskdevno)
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{
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int rc = 0;
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char *name;
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/* Note, sysfs_get_slave() returns the first slave only,
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* if there is more slaves, then return NULL
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*/
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name = sysfs_get_slave(cxt);
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if (!name)
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return -1;
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if (diskname && len) {
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strncpy(diskname, name, len);
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diskname[len - 1] = '\0';
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}
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if (diskdevno) {
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*diskdevno = sysfs_devname_to_devno(name, NULL);
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if (!*diskdevno)
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rc = -1;
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}
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free(name);
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return rc;
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}
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int sysfs_devno_to_wholedisk(dev_t dev, char *diskname,
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size_t len, dev_t *diskdevno)
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{
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struct sysfs_cxt cxt;
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int is_part = 0;
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if (!dev || sysfs_init(&cxt, dev, NULL) != 0)
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return -1;
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is_part = sysfs_has_attribute(&cxt, "partition");
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if (!is_part) {
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/*
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* Extra case for partitions mapped by device-mapper.
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*
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* All regualar partitions (added by BLKPG ioctl or kernel PT
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* parser) have the /sys/.../partition file. The partitions
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* mapped by DM don't have such file, but they have "part"
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* prefix in DM UUID.
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*/
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char *uuid = sysfs_strdup(&cxt, "dm/uuid");
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char *tmp = uuid;
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char *prefix = uuid ? strsep(&tmp, "-") : NULL;
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if (prefix && strncasecmp(prefix, "part", 4) == 0)
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is_part = 1;
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free(uuid);
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if (is_part &&
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get_dm_wholedisk(&cxt, diskname, len, diskdevno) == 0)
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/*
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* partitioned device, mapped by DM
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*/
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goto done;
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is_part = 0;
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}
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if (!is_part) {
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/*
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* unpartitioned device
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*/
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if (diskname && len) {
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if (!sysfs_get_devname(&cxt, diskname, len))
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goto err;
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}
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if (diskdevno)
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*diskdevno = dev;
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} else {
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/*
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* partitioned device
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* - readlink /sys/dev/block/8:1 = ../../block/sda/sda1
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* - dirname ../../block/sda/sda1 = ../../block/sda
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* - basename ../../block/sda = sda
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*/
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char linkpath[PATH_MAX];
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char *name;
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int linklen;
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linklen = sysfs_readlink(&cxt, NULL,
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linkpath, sizeof(linkpath) - 1);
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if (linklen < 0)
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goto err;
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linkpath[linklen] = '\0';
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stripoff_last_component(linkpath); /* dirname */
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name = stripoff_last_component(linkpath); /* basename */
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if (!name)
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goto err;
|
|
|
|
if (diskname && len) {
|
|
strncpy(diskname, name, len);
|
|
diskname[len - 1] = '\0';
|
|
}
|
|
|
|
if (diskdevno) {
|
|
*diskdevno = sysfs_devname_to_devno(name, NULL);
|
|
if (!*diskdevno)
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
done:
|
|
sysfs_deinit(&cxt);
|
|
return 0;
|
|
err:
|
|
sysfs_deinit(&cxt);
|
|
return -1;
|
|
}
|
|
|
|
#ifdef TEST_PROGRAM_SYSFS
|
|
#include <errno.h>
|
|
#include <err.h>
|
|
#include <stdlib.h>
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
struct sysfs_cxt cxt = UL_SYSFSCXT_EMPTY;
|
|
char *devname;
|
|
dev_t devno;
|
|
char path[PATH_MAX];
|
|
int i;
|
|
uint64_t u64;
|
|
ssize_t len;
|
|
|
|
if (argc != 2)
|
|
errx(EXIT_FAILURE, "usage: %s <devname>", argv[0]);
|
|
|
|
devname = argv[1];
|
|
devno = sysfs_devname_to_devno(devname, NULL);
|
|
|
|
if (!devno)
|
|
err(EXIT_FAILURE, "failed to read devno");
|
|
|
|
printf("NAME: %s\n", devname);
|
|
printf("DEVNO: %u\n", (unsigned int) devno);
|
|
printf("DEVNOPATH: %s\n", sysfs_devno_path(devno, path, sizeof(path)));
|
|
printf("DEVPATH: %s\n", sysfs_devno_to_devpath(devno, path, sizeof(path)));
|
|
printf("PARTITION: %s\n",
|
|
sysfs_devno_has_attribute(devno, "partition") ? "YES" : "NOT");
|
|
|
|
sysfs_init(&cxt, devno, NULL);
|
|
|
|
len = sysfs_readlink(&cxt, NULL, path, sizeof(path) - 1);
|
|
if (len > 0) {
|
|
path[len] = '\0';
|
|
printf("DEVNOLINK: %s\n", path);
|
|
}
|
|
|
|
printf("SLAVES: %d\n", sysfs_count_dirents(&cxt, "slaves"));
|
|
|
|
if (sysfs_read_u64(&cxt, "size", &u64))
|
|
printf("read SIZE failed\n");
|
|
else
|
|
printf("SIZE: %jd\n", u64);
|
|
|
|
if (sysfs_read_int(&cxt, "queue/hw_sector_size", &i))
|
|
printf("read SECTOR failed\n");
|
|
else
|
|
printf("SECTOR: %d\n", i);
|
|
|
|
printf("DEVNAME: %s\n", sysfs_get_devname(&cxt, path, sizeof(path)));
|
|
|
|
sysfs_deinit(&cxt);
|
|
return EXIT_SUCCESS;
|
|
}
|
|
#endif
|