Added sysfs_block.c

8 files changed, 474 insertions, 17 deletions

diff --git a/ChangeLog b/ChangeLog
index a944955..8a8a97e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,8 @@
 
+09/29/2003 - Ananth Mavinakayanahalli <ananth@in.ibm.com>
+		* Added "block" subsystem support
+		* Modified systool to use sysfs_root_device
+
 09/24/2003 - Ananth Mavinakayanahalli <ananth@in.ibm.com>
 		* Added "write" attribute functions specific to device,
 			driver and class device.
diff --git a/cmd/systool.c b/cmd/systool.c
index fe5e903..6ebbe3a 100644
--- a/cmd/systool.c
+++ b/cmd/systool.c
@@ -45,7 +45,7 @@ static unsigned char *device_to_show = NULL;	/* show only this bus device */
                                                                                 
 #define SHOW_ALL		0xff
 
-static unsigned char cmd_options[] = "aA:b:c:dDhr:v";
+static unsigned char cmd_options[] = "aA:b:B:c:dDhr:v";
 
 /*
  * binary_files - defines existing sysfs binary files. These files will be
@@ -73,6 +73,7 @@ void usage(void)
 		"\t-r <root_device>\tShow a specific root device tree\n");
 	fprintf(stdout, "\t-v\t\t\tShow all attributes with values\n");
 	fprintf(stdout, "\t-A <attribute_name>\tShow attribute value\n");
+	fprintf(stdout, "\t-B <block_name>\t Show specific block device\n");
 	fprintf(stdout, "\t-D\t\t\tShow only drivers\n");
 }
 
@@ -456,7 +457,8 @@ int show_sysfs_class(unsigned char *classname)
  */
 int show_sysfs_root(unsigned char *rootname)
 {
-	struct sysfs_device *root = NULL;
+	struct sysfs_root_device *root = NULL;
+	struct sysfs_device *device = NULL;
 	unsigned char path[SYSFS_PATH_MAX];
 
 	if (rootname == NULL) {
@@ -472,18 +474,103 @@ int show_sysfs_root(unsigned char *rootname)
 	strcat(path, SYSFS_DEVICES_DIR);
 	strcat(path, "/");
 	strcat(path, rootname);
-	root = sysfs_open_device_tree(path);
+
+	root = sysfs_open_root_device(rootname);
 	if (root == NULL) {
 		fprintf(stderr, "Error opening root device %s\n", rootname);
 		return 1;
 	}
-	fprintf(stdout, "Root Device Tree: %s\n", rootname);
-	show_device_tree(root, 2);
-	sysfs_close_device_tree(root);
 
+	fprintf(stdout, "Root Device Tree: %s\n", rootname);
+	
+	if (root->devices) {
+		dlist_for_each_data(root->devices, device,
+				struct sysfs_device) {
+			show_device_tree(device, 2);
+		}
+	}
+	sysfs_close_root_device(root);
+	
 	return 0;
 }
 
+/**
+ * show_block_partitions: show partition details
+ * @partitions: dlist of partitions
+ * returns nothing
+ */
+void show_block_partitions(struct dlist *partitions, int level)
+{
+	struct sysfs_block_partition *part = NULL;
+	struct dlist *attributes = NULL;
+
+	if (partitions == NULL)
+		return;
+	indent(level);
+	fprintf(stdout, "Partitions:\n");
+	dlist_for_each_data(partitions, part, struct sysfs_block_partition) {
+		indent(level+4);
+		fprintf(stdout, "%s\n", part->name);
+		if (show_options & (SHOW_ATTRIBUTES | SHOW_ATTRIBUTE_VALUE
+				    | SHOW_ALL_ATTRIB_VALUES)) {
+			attributes = sysfs_get_partition_attributes(part);
+			if (attributes != NULL)
+				show_attributes(attributes, level+8);
+		}
+	}
+}
+
+/**
+ * show_sysfs_block: prints out details of the given block device
+ * @blockname: name of the block device to show
+ * returns 0 on success, 1 on error
+ */
+int show_sysfs_block(unsigned char *blockname)
+{
+	struct sysfs_block_device *block = NULL;
+	struct dlist *attributes = NULL;
+
+	if (blockname == NULL) {
+		errno = EINVAL;
+		return 1;
+	}
+	
+	block = sysfs_open_block_device(blockname);
+	if (block == NULL) {
+		fprintf(stderr, "Error opening block device %s\n", blockname);
+		return 1;
+	}
+
+	fprintf(stdout, "Block: %s\n", blockname);
+	if (show_options & (SHOW_ATTRIBUTES | SHOW_ATTRIBUTE_VALUE
+			    | SHOW_ALL_ATTRIB_VALUES)) {
+		attributes = sysfs_get_blockdev_attributes(block);
+		if (attributes != NULL) 
+			show_attributes(attributes, 4);
+		attributes = sysfs_get_queue_attributes(block);
+		if (attributes != NULL) {
+			indent(4);
+			fprintf(stdout, "queue:\n");
+			show_attributes(attributes, 8);
+		}
+		attributes = sysfs_get_iosched_attributes(block);
+		if (attributes != NULL) {
+			indent(8);
+			fprintf(stdout, "iosched:\n");
+			show_attributes(attributes, 12);
+		}
+	}
+	if (block->partitions != NULL)
+		show_block_partitions(block->partitions, 4);
+	if (block->device != NULL) {
+		indent(4);
+		fprintf(stdout, "Physical device:");
+		show_device(block->device, 4);
+	}
+	sysfs_close_block_device(block);
+	
+	return 0;
+}
 
 /**
  * show_default_info: prints current buses, classes, and root devices
@@ -524,6 +611,15 @@ int show_default_info(void)
 	}
 	sysfs_close_list(list);
 			
+	strcpy(subsys, SYSFS_BLOCK_DIR);
+	list = sysfs_open_subsystem_list(subsys);
+	if (list != NULL) {
+		fprintf(stdout, "Supported sysfs block devices:\n");
+		dlist_for_each_data(list, cur, char)
+			fprintf(stdout, "\t%s\n", cur);
+	}
+	sysfs_close_list(list);
+	
 	return retval;
 }
 	
@@ -533,6 +629,7 @@ int main(int argc, char *argv[])
 	unsigned char *show_bus = NULL;
 	unsigned char *show_class = NULL;
 	unsigned char *show_root = NULL;
+	unsigned char *show_block = NULL;
 	int retval = 0;
 	int opt;
 	extern int optind;
@@ -556,6 +653,9 @@ int main(int argc, char *argv[])
 		case 'b':
 			show_bus = optarg;	
 			break;
+		case 'B':
+			show_block = optarg;
+			break;
 		case 'c':
 			show_class = optarg;	
 			break;
@@ -602,9 +702,11 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
-	if ((show_bus == NULL && show_class == NULL && show_root == NULL) 
-	    && (show_options & (SHOW_ATTRIBUTES | SHOW_ATTRIBUTE_VALUE 
-	    | SHOW_DEVICES | SHOW_DRIVERS | SHOW_ALL_ATTRIB_VALUES))) {
+	if ((show_bus == NULL && show_class == NULL && 
+		show_root == NULL && show_block == NULL) && 
+			(show_options & (SHOW_ATTRIBUTES | 
+				SHOW_ATTRIBUTE_VALUE | SHOW_DEVICES | 
+				SHOW_DRIVERS | SHOW_ALL_ATTRIB_VALUES))) {
 		fprintf(stderr, 
 			"Please specify a bus, class, or root device\n");
 		usage();
@@ -620,8 +722,11 @@ int main(int argc, char *argv[])
 		retval = show_sysfs_class(show_class);
 	if (show_root != NULL)
 		retval = show_sysfs_root(show_root);
+	if (show_block != NULL)
+		retval = show_sysfs_block(show_block);
 
-	if (show_bus == NULL && show_class == NULL && show_root == NULL) 
+	if (show_bus == NULL && show_class == NULL && 
+			show_root == NULL && show_block == NULL) 
 		retval = show_default_info();
 
 	exit(retval);
diff --git a/include/libsysfs.h b/include/libsysfs.h
index 2a96b6d..da0a3ee 100644
--- a/include/libsysfs.h
+++ b/include/libsysfs.h
@@ -33,6 +33,7 @@
 #define SYSFS_PROC_MNTS		"/proc/mounts"
 #define SYSFS_BUS_DIR		"/bus"
 #define SYSFS_CLASS_DIR		"/class"
+#define SYSFS_BLOCK_DIR		"/block"
 #define SYSFS_DEVICES_DIR	"/devices"
 #define SYSFS_DEVICES_NAME	"devices"
 #define SYSFS_DRIVERS_DIR	"/drivers"
@@ -40,6 +41,10 @@
 #define SYSFS_NAME_ATTRIBUTE	"name"
 #define SYSFS_UNKNOWN		"unknown"
 
+/* Some "block" subsystem specific #defines */
+#define SYSFS_QUEUE_NAME	"queue"
+#define SYSFS_IOSCHED_NAME	"iosched"
+
 #define SYSFS_PATH_MAX		255
 #define	SYSFS_NAME_LEN		50
 #define SYSFS_BUS_ID_SIZE	20
@@ -127,6 +132,23 @@ struct sysfs_class {
 	struct sysfs_directory *directory;	
 };
 
+struct sysfs_block_device {
+	struct sysfs_device *device;	/* the physical device */
+	struct dlist *partitions;	/* struct sysfs_block_partition */
+	unsigned char name[SYSFS_NAME_LEN];
+	unsigned char path[SYSFS_PATH_MAX];
+
+	/* for internal use only */
+	struct sysfs_directory *directory;
+};
+
+struct sysfs_block_partition {
+	unsigned char name[SYSFS_NAME_LEN];
+
+	/* for internal use only */
+	struct sysfs_directory *directory;
+};
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -226,6 +248,20 @@ extern int sysfs_find_device_class_name(unsigned char *bus_id,
 extern int sysfs_write_classdev_attr(unsigned char *dev,
 		unsigned char *attrib, unsigned char *value);
 
+/* generic sysfs block access */
+extern void sysfs_close_block_partition
+			(struct sysfs_block_partition *partition);
+extern void sysfs_close_block_device(struct sysfs_block_device *block);
+extern struct sysfs_block_device *sysfs_open_block_device(unsigned char *name);
+extern struct dlist *sysfs_get_blockdev_attributes
+					(struct sysfs_block_device *block);
+extern struct dlist *sysfs_get_partition_attributes
+					(struct sysfs_block_partition *part);
+extern struct dlist *sysfs_get_queue_attributes
+					(struct sysfs_block_device *block);
+extern struct dlist *sysfs_get_iosched_attributes
+					(struct sysfs_block_device *block);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/Makefile.am b/lib/Makefile.am
index d343f01..2b5049a 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,5 +1,5 @@
 lib_LIBRARIES = libsysfs.a
 libsysfs_a_SOURCES = sysfs_utils.c sysfs_dir.c sysfs_bus.c sysfs_class.c \
-	sysfs_device.c sysfs_driver.c sysfs.h dlist.c
+	sysfs_device.c sysfs_driver.c sysfs_block.c sysfs.h dlist.c
 INCLUDES = -I../include
 
diff --git a/lib/Makefile.in b/lib/Makefile.in
index a2e859e..2ecbd5f 100644
--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -77,7 +77,7 @@ am__quote = @am__quote@
 install_sh = @install_sh@
 lib_LIBRARIES = libsysfs.a
 libsysfs_a_SOURCES = sysfs_utils.c sysfs_dir.c sysfs_bus.c sysfs_class.c \
-	sysfs_device.c sysfs_driver.c sysfs.h dlist.c
+	sysfs_device.c sysfs_driver.c sysfs_block.c sysfs.h dlist.c
 
 INCLUDES = -I../include
 subdir = lib
@@ -90,7 +90,8 @@ libsysfs_a_AR = $(AR) cru
 libsysfs_a_LIBADD =
 am_libsysfs_a_OBJECTS = sysfs_utils.$(OBJEXT) sysfs_dir.$(OBJEXT) \
 	sysfs_bus.$(OBJEXT) sysfs_class.$(OBJEXT) \
-	sysfs_device.$(OBJEXT) sysfs_driver.$(OBJEXT) dlist.$(OBJEXT)
+	sysfs_device.$(OBJEXT) sysfs_driver.$(OBJEXT) \
+	sysfs_block.$(OBJEXT) dlist.$(OBJEXT)
 libsysfs_a_OBJECTS = $(am_libsysfs_a_OBJECTS)
 
 DEFS = @DEFS@
@@ -100,8 +101,8 @@ LDFLAGS = @LDFLAGS@
 LIBS = @LIBS@
 depcomp = $(SHELL) $(top_srcdir)/depcomp
 am__depfiles_maybe = depfiles
-@AMDEP_TRUE@DEP_FILES = ./$(DEPDIR)/dlist.Po ./$(DEPDIR)/sysfs_bus.Po \
-@AMDEP_TRUE@	./$(DEPDIR)/sysfs_class.Po \
+@AMDEP_TRUE@DEP_FILES = ./$(DEPDIR)/dlist.Po ./$(DEPDIR)/sysfs_block.Po \
+@AMDEP_TRUE@	./$(DEPDIR)/sysfs_bus.Po ./$(DEPDIR)/sysfs_class.Po \
 @AMDEP_TRUE@	./$(DEPDIR)/sysfs_device.Po \
 @AMDEP_TRUE@	./$(DEPDIR)/sysfs_dir.Po \
 @AMDEP_TRUE@	./$(DEPDIR)/sysfs_driver.Po \
@@ -168,6 +169,7 @@ distclean-compile:
 	-rm -f *.tab.c
 
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/dlist.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sysfs_block.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sysfs_bus.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sysfs_class.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/sysfs_device.Po@am__quote@
diff --git a/lib/sysfs_block.c b/lib/sysfs_block.c
new file mode 100644
index 0000000..601f575
--- /dev/null
+++ b/lib/sysfs_block.c
@@ -0,0 +1,309 @@
+/*
+ * sysfs_block.c
+ *
+ * Generic block utility functions for libsysfs
+ *
+ * Copyright (C) IBM Corp. 2003
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library 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
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/*
+ * NOTES:
+ * 	Write functions to:
+ * 		Device major/minor given a device
+ * 		As of now, only the "block" device has writable attribs. 
+ * 			Library has to take care of navigating to the attribute
+ * 			(may be at various directory levels)
+ */
+
+#include "libsysfs.h"
+#include "sysfs.h"
+
+void sysfs_del_partition(void *partition)
+{
+	sysfs_close_block_partition((struct sysfs_block_partition *)partition);
+}
+
+/**
+ * sysfs_close_block_partition: closes a block partition
+ * @partition: sysfs_block_partition to close
+ */
+void sysfs_close_block_partition(struct sysfs_block_partition *partition)
+{
+	if (partition != NULL) {
+		if (partition->directory != NULL)
+/*	reuse sysfs_dir from the earlier structure - just set it to NULL here 
+ *	free it while closing sysfs_block_device->directory
+ * 		sysfs_close_directory(partition->directory);*/
+			partition->directory = NULL;
+	}
+}
+
+/**
+ * sysfs_close_block_device: closes a sysfs_block_device
+ * @block: sysfs_block_device structure
+ */
+void sysfs_close_block_device(struct sysfs_block_device *block)
+{
+	if (block != NULL) {
+		if (block->directory != NULL) 
+			sysfs_close_directory(block->directory);
+		if (block->device != NULL) 
+			sysfs_close_device(block->device);
+		if (block->partitions  != NULL)
+			dlist_destroy(block->partitions);
+	}
+}
+
+/**
+ * alloc_block_device: allocate a sysfs_block_device
+ * returns sysfs_block_device or NULL
+ */
+static struct sysfs_block_device *alloc_block_device()
+{
+	return (struct sysfs_block_device *)
+		calloc(1, sizeof(struct sysfs_block_device));
+}
+
+/**
+ * open_block_dir: opens a sysfs block directory
+ * returns sysfs_directory on success or NULL on error
+ */
+static struct sysfs_directory *open_block_dir(const unsigned char *name)
+{
+	unsigned char path[SYSFS_PATH_MAX];
+	struct sysfs_directory *directory = NULL;
+
+	if (name == NULL) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	memset(path, 0, SYSFS_PATH_MAX);
+	if ((sysfs_get_mnt_path(path, SYSFS_PATH_MAX)) != 0) {
+		dprintf("Error getting sysfs mount path\n");
+		return NULL;
+	}
+
+	strcat(path, SYSFS_BLOCK_DIR);
+	strcat(path, "/");
+	strcat(path, name);
+	directory = sysfs_open_directory(path);
+	if (directory == NULL) {
+		dprintf("Block device %s not supported on this system",	name);
+		return NULL;
+	}
+	if ((sysfs_read_directory(directory)) != 0) {
+		dprintf("Error reading directory %s\n", directory->path);
+		sysfs_close_directory(directory);
+		return NULL;
+	}
+	sysfs_read_all_subdirs(directory);
+
+	return directory;
+}
+
+/**
+ * alloc_block_partition: alloc a sysfs_block_partition structure
+ */
+static struct sysfs_block_partition *alloc_block_partition(void)
+{
+	return(struct sysfs_block_partition *)
+			calloc(1, sizeof(struct sysfs_block_partition));
+}
+
+/**
+ * get_all_block_devices: Retrieves details of block directory
+ * @block: sysfs_block_device for which details are required
+ * returns 0 on success, -1 on failure
+ */
+static int get_all_block_devices(struct sysfs_block_device *block)
+{
+	struct sysfs_directory *cur = NULL;
+	struct sysfs_block_partition *part = NULL;
+
+	if (block == NULL || block->directory == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	dlist_for_each_data(block->directory->subdirs, cur, 
+						struct sysfs_directory) {
+		switch(strcmp(cur->name, SYSFS_QUEUE_NAME)) {
+			case 0:	/* this is the "queue" directory */
+				if ((sysfs_read_directory(cur)) < 0) {
+					dprintf("Error reading directory %s\n",
+							cur->path);
+					return -1;
+				}
+				break;
+			default: /* these are the partitions */
+				part = alloc_block_partition();
+				if (part == NULL) {
+					perror("calloc");
+					return -1;
+				}
+				part->directory = cur;
+				strcpy(part->name, cur->name);
+				if (block->partitions == NULL) 
+					block->partitions = 
+						dlist_new_with_delete
+						(sizeof(struct 
+							sysfs_block_partition),
+							 sysfs_del_partition);
+				dlist_unshift(block->partitions, part);
+				break;
+		}
+	}
+	return 0;		
+}
+
+/**
+ * sysfs_open_block_device: opens the specific block device and all its related
+ * 		details as partitions, etc
+ * returns sysfs_block_device struct on success and NULL on error
+ */
+struct sysfs_block_device *sysfs_open_block_device(unsigned char *name)
+{
+	struct sysfs_block_device *block = NULL;
+	struct sysfs_directory *blockdir = NULL;
+	struct sysfs_link *curlink = NULL;
+
+	if (name == NULL) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	block = alloc_block_device();
+	if (block == NULL) {
+		perror("calloc");
+		return NULL;
+	}
+	strcpy(block->name, name);
+	blockdir = open_block_dir(name);
+	if (blockdir == NULL) {
+		sysfs_close_block_device(block);
+		return NULL;
+	}
+	strcpy(block->path, blockdir->path);
+	block->directory = blockdir;
+	if ((get_all_block_devices(block)) != 0) {
+		dprintf("Error retrieving devices for block %s\n", name);
+		sysfs_close_block_device(block);
+		return NULL;
+	}
+	/* check if the "block" device has a link to the physical device */
+	if (block->directory->links != NULL) {
+		dlist_for_each_data(block->directory->links, curlink,
+				struct sysfs_link) {
+			block->device = sysfs_open_device(curlink->target);
+			if (block->device == NULL) {
+				dprintf("Error opening device at %s\n",
+						curlink->target);
+			}
+		}
+	}
+
+	return block;
+}
+
+/** 
+ * sysfs_get_blockdev_attributes: returns attributes for the block device
+ * @block: block device for which attribs are to be returned
+ */
+struct dlist *sysfs_get_blockdev_attributes(struct sysfs_block_device *block)
+{
+	if (block == NULL || block->directory == NULL) 
+		return NULL;
+	
+	return(block->directory->attributes);
+}
+		
+/** 
+ * sysfs_get_partition_attributes: returns attributes for the block 
+ * 					device partition
+ * @block: block device partition for which attribs are to be returned
+ */
+struct dlist *sysfs_get_partition_attributes
+				(struct sysfs_block_partition *part)
+{
+	if (part == NULL || part->directory == NULL) 
+		return NULL;
+
+	return(part->directory->attributes);
+}
+
+/**
+ * sysfs_get_queue_attributes: returns attributes for the block device's
+ * 				QUEUE parameters. Used to set #of queued
+ * 				requests as well as the choice of IO
+ * 				scheduler
+ * @block: block device for which the attributes are needed.
+ */
+struct dlist *sysfs_get_queue_attributes(struct sysfs_block_device *block)
+{
+	struct dlist *list = NULL;
+	struct sysfs_directory *dir = NULL;
+	unsigned int found = 0;
+
+	dlist_for_each_data(block->directory->subdirs, dir, 
+					struct sysfs_directory) {
+		if ((strcmp(dir->name, SYSFS_QUEUE_NAME)) != 0) 
+			continue;
+		else 
+			return (dir->attributes);
+	}
+	return NULL;
+}
+
+/**
+ * sysfs_get_iosched_attributes: returns attributes for the block device's
+ * 				IOSCHED parameters for the given device
+ * @block: block device for which the attributes are needed
+ * returns a dlist of iosched attributes. 
+ */
+struct dlist *sysfs_get_iosched_attributes(struct sysfs_block_device *block)
+{
+	struct dlist *list = NULL;
+	struct sysfs_directory *dir = NULL, *new = NULL;
+	unsigned int found = 0;
+	
+	dlist_for_each_data(block->directory->subdirs, dir, 
+					struct sysfs_directory) {
+		if ((strcmp(dir->name, SYSFS_QUEUE_NAME)) != 0) 
+			continue;
+		else {
+			found = 1;
+			break;
+		}
+	}
+	if (found) {
+		/* 
+		 * this is the queue directory - read this and the
+		 * iosched directory too
+		 */
+		dlist_for_each_data(dir->subdirs, new, 
+						struct sysfs_directory) {
+			if ((strcmp(new->name, SYSFS_IOSCHED_NAME)) == 0) 
+				if ((sysfs_read_directory(new)) == 0) 
+					return new->attributes;
+		}
+	}
+	dprintf("IOSCHED attributes not found\n");
+	return NULL;
+}
+			
diff --git a/lib/sysfs_class.c b/lib/sysfs_class.c
index 6c969b5..9172a1e 100644
--- a/lib/sysfs_class.c
+++ b/lib/sysfs_class.c
@@ -264,7 +264,7 @@ struct sysfs_class *sysfs_open_class(const unsigned char *name)
 
 	cls = alloc_class();
 	if (cls == NULL) {
-		perror("malloc");
+		perror("calloc");
 		return NULL;
 	}
 	strcpy(cls->name, name);	
diff --git a/lib/sysfs_dir.c b/lib/sysfs_dir.c
index 1d730e7..46ebd52 100644
--- a/lib/sysfs_dir.c
+++ b/lib/sysfs_dir.c
@@ -525,10 +525,11 @@ int sysfs_read_directory(struct sysfs_directory *sysdir)
 				}
 			}
 			                        
-			if (sysdir->attributes == NULL)
+			if (sysdir->attributes == NULL) {
 				sysdir->attributes = dlist_new_with_delete
 					(sizeof(struct sysfs_attribute),
 					 		sysfs_del_attribute);
+			}
 			dlist_unshift(sysdir->attributes, attr);
 		} else if (S_ISDIR(astats.st_mode)) {
 			subdir = sysfs_open_directory(file_path);