busybox/libbb/find_root_device.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <stdlib.h>
#include "libbb.h"
extern char *find_real_root_device_name(const char* name)
{
DIR *dir;
struct dirent *entry;
struct stat statBuf, rootStat;
char *fileName = NULL;
dev_t dev;
if (stat("/", &rootStat) != 0)
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bb_perror_msg("could not stat '/'");
else {
/* This check is here in case they pass in /dev name */
if ((rootStat.st_mode & S_IFMT) == S_IFBLK)
dev = rootStat.st_rdev;
else
dev = rootStat.st_dev;
dir = opendir("/dev");
if (!dir)
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bb_perror_msg("could not open '/dev'");
else {
while((entry = readdir(dir)) != NULL) {
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const char *myname = entry->d_name;
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/* Must skip ".." since that is "/", and so we
* would get a false positive on ".." */
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if (myname[0] == '.' && myname[1] == '.' && !myname[2])
continue;
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fileName = concat_path_file("/dev", myname);
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/* Some char devices have the same dev_t as block
* devices, so make sure this is a block device */
if (stat(fileName, &statBuf) == 0 &&
S_ISBLK(statBuf.st_mode)!=0 &&
statBuf.st_rdev == dev)
break;
free(fileName);
fileName=NULL;
}
closedir(dir);
}
}
if(fileName==NULL)
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fileName = bb_xstrdup("/dev/root");
return fileName;
}
/* END CODE */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/