/*
* devno.c - find a particular device by its device number (major/minor)
*
* Copyright (C) 2000, 2001, 2003 Theodore Ts'o
* Copyright (C) 2001 Andreas Dilger
*
* %Begin-Header%
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#include <dirent.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_MKDEV_H
#include <sys/mkdev.h>
#endif
#include <fcntl.h>
#include <inttypes.h>
#include "blkidP.h"
#include "pathnames.h"
#include "sysfs.h"
static char *blkid_strconcat(const char *a, const char *b, const char *c)
{
char *res, *p;
size_t len, al, bl, cl;
al = a ? strlen(a) : 0;
bl = b ? strlen(b) : 0;
cl = c ? strlen(c) : 0;
len = al + bl + cl;
if (!len)
return NULL;
p = res = malloc(len + 1);
if (!res)
return NULL;
if (al) {
memcpy(p, a, al);
p += al;
}
if (bl) {
memcpy(p, b, bl);
p += bl;
}
if (cl) {
memcpy(p, c, cl);
p += cl;
}
*p = '\0';
return res;
}
/*
* This function adds an entry to the directory list
*/
static void add_to_dirlist(const char *dir, const char *subdir,
struct dir_list **list)
{
struct dir_list *dp;
dp = malloc(sizeof(struct dir_list));
if (!dp)
return;
dp->name = subdir ? blkid_strconcat(dir, "/", subdir) :
dir ? strdup(dir) : NULL;
if (!dp->name) {
free(dp);
return;
}
dp->next = *list;
*list = dp;
}
/*
* This function frees a directory list
*/
static void free_dirlist(struct dir_list **list)
{
struct dir_list *dp, *next;
for (dp = *list; dp; dp = next) {
next = dp->next;
free(dp->name);
free(dp);
}
*list = NULL;
}
void blkid__scan_dir(char *dirname, dev_t devno, struct dir_list **list,
char **devname)
{
DIR *dir;
struct dirent *dp;
struct stat st;
if ((dir = opendir(dirname)) == NULL)
return;
while ((dp = readdir(dir)) != NULL) {
#ifdef _DIRENT_HAVE_D_TYPE
if (dp->d_type != DT_UNKNOWN && dp->d_type != DT_BLK &&
dp->d_type != DT_LNK && dp->d_type != DT_DIR)
continue;
#endif
if (dp->d_name[0] == '.' &&
((dp->d_name[1] == 0) ||
((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
continue;
if (fstatat(dirfd(dir), dp->d_name, &st, 0))
continue;
if (S_ISBLK(st.st_mode) && st.st_rdev == devno) {
*devname = blkid_strconcat(dirname, "/", dp->d_name);
DBG(DEVNO, ul_debug("found 0x%llx at %s", (long long)devno,
*devname));
break;
}
if (!list || !S_ISDIR(st.st_mode))
continue;
/* add subdirectory (but not symlink) to the list */
#ifdef _DIRENT_HAVE_D_TYPE
if (dp->d_type == DT_LNK)
continue;
if (dp->d_type == DT_UNKNOWN)
#endif
{
if (fstatat(dirfd(dir), dp->d_name, &st, 1) ||
!S_ISDIR(st.st_mode))
continue; /* symlink or lstat() failed */
}
if (*dp->d_name == '.' || (
#ifdef _DIRENT_HAVE_D_TYPE
dp->d_type == DT_DIR &&
#endif
strcmp(dp->d_name, "shm") == 0))
/* ignore /dev/.{udev,mount,mdadm} and /dev/shm */
continue;
add_to_dirlist(dirname, dp->d_name, list);
}
closedir(dir);
return;
}
/* Directories where we will try to search for device numbers */
static const char *devdirs[] = { "/devices", "/devfs", "/dev", NULL };
/**
* SECTION: misc
* @title: Miscellaneous utils
* @short_description: mix of various utils for low-level and high-level API
*/
static char *scandev_devno_to_devpath(dev_t devno)
{
struct dir_list *list = NULL, *new_list = NULL;
char *devname = NULL;
const char **dir;
/*
* Add the starting directories to search in reverse order of
* importance, since we are using a stack...
*/
for (dir = devdirs; *dir; dir++)
add_to_dirlist(*dir, NULL, &list);
while (list) {
struct dir_list *current = list;
list = list->next;
DBG(DEVNO, ul_debug("directory %s", current->name));
blkid__scan_dir(current->name, devno, &new_list, &devname);
free(current->name);
free(current);
if (devname)
break;
/*
* If we're done checking at this level, descend to
* the next level of subdirectories. (breadth-first)
*/
if (list == NULL) {
list = new_list;
new_list = NULL;
}
}
free_dirlist(&list);
free_dirlist(&new_list);
return devname;
}
/**
* blkid_devno_to_devname:
* @devno: device number
*
* This function finds the pathname to a block device with a given
* device number.
*
* Returns: a pointer to allocated memory to the pathname on success,
* and NULL on failure.
*/
char *blkid_devno_to_devname(dev_t devno)
{
char *path;
char buf[PATH_MAX];
path = sysfs_devno_to_devpath(devno, buf, sizeof(buf));
if (path)
path = strdup(path);
if (!path)
path = scandev_devno_to_devpath(devno);
if (!path) {
DBG(DEVNO, ul_debug("blkid: couldn't find devno 0x%04lx",
(unsigned long) devno));
} else {
DBG(DEVNO, ul_debug("found devno 0x%04llx as %s", (long long)devno, path));
}
return path;
}
/**
* blkid_devno_to_wholedisk:
* @dev: device number
* @diskname: buffer to return diskname (or NULL)
* @len: diskname buffer size (or 0)
* @diskdevno: pointer to returns devno of entire disk (or NULL)
*
* This function uses sysfs to convert the @devno device number to the *name*
* of the whole disk. The function DOES NOT return full device name. The @dev
* argument could be partition or whole disk -- both is converted.
*
* For example: sda1, 0x0801 --> sda, 0x0800
*
* For conversion to the full disk *path* use blkid_devno_to_devname(), for
* example:
*
* <informalexample>
* <programlisting>
*
* dev_t dev = 0x0801, disk; // sda1 = 8:1
* char *diskpath, diskname[32];
*
* blkid_devno_to_wholedisk(dev, diskname, sizeof(diskname), &disk);
* diskpath = blkid_devno_to_devname(disk);
*
* // print "0x0801: sda, /dev/sda, 8:0
* printf("0x%x: %s, %s, %d:%d\n",
* dev, diskname, diskpath, major(disk), minor(disk));
*
* free(diskpath);
*
* </programlisting>
* </informalexample>
*
* Returns: 0 on success or -1 in case of error.
*/
int blkid_devno_to_wholedisk(dev_t dev, char *diskname,
size_t len, dev_t *diskdevno)
{
return sysfs_devno_to_wholedisk( dev, diskname, len, diskdevno);
}
/*
* Returns 1 if the @major number is associated with @drvname.
*/
int blkid_driver_has_major(const char *drvname, int drvmaj)
{
FILE *f;
char buf[128];
int match = 0;
f = fopen(_PATH_PROC_DEVICES, "r" UL_CLOEXECSTR);
if (!f)
return 0;
while (fgets(buf, sizeof(buf), f)) { /* skip to block dev section */
if (strncmp("Block devices:\n", buf, sizeof(buf)) == 0)
break;
}
while (fgets(buf, sizeof(buf), f)) {
int maj;
char name[64 + 1];
if (sscanf(buf, "%d %64[^\n ]", &maj, name) != 2)
continue;
if (maj == drvmaj && strcmp(name, drvname) == 0) {
match = 1;
break;
}
}
fclose(f);
DBG(DEVNO, ul_debug("major %d %s associated with '%s' driver",
drvmaj, match ? "is" : "is NOT", drvname));
return match;
}
#ifdef TEST_PROGRAM
int main(int argc, char** argv)
{
char *devname, *tmp;
char diskname[PATH_MAX];
int devmaj, devmin;
dev_t devno, disk_devno;
const char *errmsg = "Couldn't parse %s: %s\n";
blkid_init_debug(BLKID_DEBUG_ALL);
if ((argc != 2) && (argc != 3)) {
fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n"
"Resolve a device number to a device name\n",
argv[0], argv[0]);
exit(1);
}
if (argc == 2) {
devno = strtoul(argv[1], &tmp, 0);
if (*tmp) {
fprintf(stderr, errmsg, "device number", argv[1]);
exit(1);
}
} else {
devmaj = strtoul(argv[1], &tmp, 0);
if (*tmp) {
fprintf(stderr, errmsg, "major number", argv[1]);
exit(1);
}
devmin = strtoul(argv[2], &tmp, 0);
if (*tmp) {
fprintf(stderr, errmsg, "minor number", argv[2]);
exit(1);
}
devno = makedev(devmaj, devmin);
}
printf("Looking for device 0x%04llx\n", (long long)devno);
devname = blkid_devno_to_devname(devno);
free(devname);
printf("Looking for whole-device for 0x%04llx\n", (long long)devno);
if (blkid_devno_to_wholedisk(devno, diskname,
sizeof(diskname), &disk_devno) == 0)
printf("found devno 0x%04llx as /dev/%s\n", (long long) disk_devno, diskname);
return 0;
}
#endif
