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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
/* Find block device /dev/XXX which contains specified file
* We handle /dev/dir/dir/dir too, at a cost of ~80 more bytes code */
/* Do not reallocate all this stuff on each recursion */
enum { DEVNAME_MAX = 256 };
struct arena {
struct stat st;
dev_t dev;
/* Was PATH_MAX, but we recurse _/dev_. We can assume
* people are not crazy enough to have mega-deep tree there */
char devpath[DEVNAME_MAX];
};
static char *find_block_device_in_dir(struct arena *ap)
{
DIR *dir;
struct dirent *entry;
char *retpath = NULL;
int len, rem;
len = strlen(ap->devpath);
rem = DEVNAME_MAX-2 - len;
if (rem <= 0)
return NULL;
dir = opendir(ap->devpath);
if (!dir)
return NULL;
ap->devpath[len++] = '/';
while ((entry = readdir(dir)) != NULL) {
safe_strncpy(ap->devpath + len, entry->d_name, rem);
/* lstat: do not follow links */
if (lstat(ap->devpath, &ap->st) != 0)
continue;
if (S_ISBLK(ap->st.st_mode) && ap->st.st_rdev == ap->dev) {
retpath = xstrdup(ap->devpath);
break;
}
if (S_ISDIR(ap->st.st_mode)) {
/* Do not recurse for '.' and '..' */
if (DOT_OR_DOTDOT(entry->d_name))
continue;
retpath = find_block_device_in_dir(ap);
if (retpath)
break;
}
}
closedir(dir);
return retpath;
}
char* FAST_FUNC find_block_device(const char *path)
{
struct arena a;
if (stat(path, &a.st) != 0)
return NULL;
a.dev = S_ISBLK(a.st.st_mode) ? a.st.st_rdev : a.st.st_dev;
strcpy(a.devpath, "/dev");
return find_block_device_in_dir(&a);
}
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