X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;ds=sidebyside;f=libbb%2Ffind_root_device.c;h=8436cd664fcb28091299126baf82dfc5e3a59c4d;hb=b2320370be14811459718b9fe418efed75ea3615;hp=81824a216e6dec0d975607145120bd0241f11163;hpb=c7bda1ce659294d6e22c06e087f6f265983c7578;p=oweals%2Fbusybox.git

diff --git a/libbb/find_root_device.c b/libbb/find_root_device.c
index 81824a216..8436cd664 100644
--- a/libbb/find_root_device.c
+++ b/libbb/find_root_device.c
@@ -4,82 +4,72 @@
  *
  * 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
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-#include <stdio.h>
-#include <string.h>
-#include <dirent.h>
-#include <stdlib.h>
 #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];
+};
 
-extern char *find_real_root_device_name(const char* name)
+static char *find_block_device_in_dir(struct arena *ap)
 {
 	DIR *dir;
 	struct dirent *entry;
-	struct stat statBuf, rootStat;
-	char *fileName = NULL;
-	dev_t dev;
+	char *retpath = NULL;
+	int len, rem;
 
-	if (stat("/", &rootStat) != 0)
-		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;
+	len = strlen(ap->devpath);
+	rem = DEVNAME_MAX-2 - len;
+	if (rem <= 0)
+		return NULL;
 
-		dir = opendir("/dev");
-		if (!dir)
-			bb_perror_msg("could not open '/dev'");
-		else {
-			while((entry = readdir(dir)) != NULL) {
-				const char *myname = entry->d_name;
-				/* Must skip ".." since that is "/", and so we
-				 * would get a false positive on ".."  */
-				if (myname[0] == '.' && myname[1] == '.' && !myname[2])
-					continue;
+	dir = opendir(ap->devpath);
+	if (!dir)
+		return NULL;
 
-				fileName = concat_path_file("/dev", myname);
+	ap->devpath[len++] = '/';
 
-				/* 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);
+	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;
 		}
 	}
-	if(fileName==NULL)
-		fileName = bb_xstrdup("/dev/root");
-	return fileName;
+	closedir(dir);
+
+	return retpath;
 }
 
+char* FAST_FUNC find_block_device(const char *path)
+{
+	struct arena a;
 
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/
+	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);
+}