[PATCH] pre-libsysfs-0.4.0 patch

I am sending you a pre-release patch. It's everything that's in our
current CVS tree. It adds the functionality you've been looking for. Please
play with this before checking it into your tree, I'd like to know if
it's ok with you or if you find problems. I have tested this out with
test.all and the perl regression test. Let me know what you think.

Still need to do more testing for our work and add some more functions
related to the changes.

I've gone into namedev.c and udev-add.c to make the necessary changes
in line with the library. I have not gone and edited any of the "extras".


Changes:

1) Libsysfs object structures work more as handles now, their included
directories or devices are labeled private. If you need attributes
from a sysfs_class_device, call the available function and don't access
the directory directly. Same holds true for a sysfs_class_device
sysfs_device. Do not access the link directly but call the function
sysfs_get_classdev_device() instead. We only populate entries upon
request, makes things faster and uses less memory.

2) Added sysfs_get_classdev_parent() as requested.

3) Changed getpagesize to sysconf.

4) Added sysfs_refresh_attributes function for refreshing views of
attribute lists. We still need to add refresh for links and subdirs. All
udev needs to do is keep calling sysfs_get_classdev_attr() and that will
internally call the refresh routine.

1 files changed, 323 insertions, 80 deletions

diff --git a/libsysfs/sysfs_dir.c b/libsysfs/sysfs_dir.c
index e983d0eff4..ac2ecfcbe1 100644
--- a/libsysfs/sysfs_dir.c
+++ b/libsysfs/sysfs_dir.c
@@ -187,6 +187,13 @@ int sysfs_write_attribute(struct sysfs_attribute *sysattr,
 		return -1;
 	}
 	if (sysattr->method & SYSFS_METHOD_SHOW) {
+		/*
+		 * read attribute again to see if we can get an updated value 
+		 */
+		if ((sysfs_read_attribute(sysattr)) != 0) {
+			dprintf("Error reading attribute\n");
+			return -1;
+		}
 		if ((strncmp(sysattr->value, new_value, sysattr->len)) == 0) {
 			dprintf("Attribute %s already has the requested value %s\n",
 					sysattr->name, new_value);
@@ -254,7 +261,7 @@ int sysfs_read_attribute(struct sysfs_attribute *sysattr)
 	unsigned char *fbuf = NULL;
 	unsigned char *vbuf = NULL;
 	size_t length = 0;
-	int pgsize = 0;
+	long pgsize = 0;
 	int fd;
 
 	if (sysattr == NULL) {
@@ -269,7 +276,7 @@ int sysfs_read_attribute(struct sysfs_attribute *sysattr)
 #ifdef __KLIBC__
 	pgsize = 0x4000;
 #else
-	pgsize = getpagesize();
+	pgsize = sysconf(_SC_PAGESIZE);
 #endif
 	fbuf = (unsigned char *)calloc(1, pgsize+1);
 	if (fbuf == NULL) {
@@ -288,6 +295,14 @@ int sysfs_read_attribute(struct sysfs_attribute *sysattr)
 		free(fbuf);
 		return -1;
 	}
+	if (sysattr->len > 0) {
+		if ((sysattr->len == length) && 
+				(!(strncmp(sysattr->value, fbuf, length)))) {
+			close(fd);
+			return 0;
+		}
+		free(sysattr->value);
+	}
 	sysattr->len = length;
 	close(fd);
 	vbuf = (unsigned char *)realloc(fbuf, length+1);
@@ -389,6 +404,7 @@ void sysfs_close_directory(struct sysfs_directory *sysdir)
 		if (sysdir->attributes != NULL) 
 			dlist_destroy(sysdir->attributes);
 		free(sysdir);
+		sysdir = NULL;
 	}
 }
 
@@ -424,10 +440,12 @@ int sysfs_read_all_subdirs(struct sysfs_directory *sysdir)
 		errno = EINVAL;
 		return -1;
 	}
-	if (sysdir->subdirs == NULL)
-		return 0;
+	if (sysdir->subdirs == NULL) 
+		if ((sysfs_read_dir_subdirs(sysdir) != 0) 
+		    || sysdir->subdirs == NULL)
+			return 0;
 	dlist_for_each_data(sysdir->subdirs, cursub, struct sysfs_directory) {
-		if (sysfs_read_directory(cursub) != 0) 
+		if ((sysfs_read_directory(cursub)) != 0) 
 			dprintf ("Error reading subdirectory %s\n",
 				cursub->name);
 	}
@@ -494,18 +512,131 @@ struct sysfs_link *sysfs_open_link(const unsigned char *linkpath)
 }
 
 /**
- * sysfs_read_directory: grabs attributes, links, and subdirectories
+ * sysfs_refresh_attributes: Refresh attributes list
+ * @attrlist: list of attributes to refresh
+ * Returns 0 on success, 1 on failure
+ */
+int sysfs_refresh_attributes(struct dlist *attrlist)
+{
+	struct sysfs_attribute *attr = NULL;
+
+	if (attrlist == NULL) {
+		errno = EINVAL;
+		return 1;
+	}
+	dlist_for_each_data(attrlist, attr, struct sysfs_attribute) {
+		if (attr->method & SYSFS_METHOD_SHOW) {
+			if ((sysfs_read_attribute(attr)) != 0) {
+				dprintf("Error reading attribute %s\n", attr->path);
+				if ((sysfs_path_is_file(attr->path)) != 0) {
+					dprintf("Attr %s no longer exists\n", 
+								attr->name);
+				}
+			}
+		} else {
+			if ((sysfs_path_is_file(attr->path)) != 0) {
+				dprintf("Attr %s no longer exists\n", 
+								attr->name);
+			}
+		}
+	}
+	if (attrlist->count == 0) {
+		dprintf("No attributes in the list, destroying list now\n");
+		dlist_destroy(attrlist);
+		attrlist = NULL;
+		return 1;
+	}
+	return 0;
+}
+
+/**
+ * add_attribute: open and add attribute at path to given directory
+ * @sysdir: directory to add attribute to
+ * @path: path to attribute
+ * returns 0 with success and -1 with error.
+ */
+static int add_attribute(struct sysfs_directory *sysdir, 
+					const unsigned char *path)
+{
+	struct sysfs_attribute *attr = NULL;
+
+	attr = sysfs_open_attribute(path);
+	if (attr == NULL) {
+		dprintf("Error opening attribute %s\n",	path);
+		return -1;
+	}
+	if (attr->method & SYSFS_METHOD_SHOW) {
+		if ((sysfs_read_attribute(attr)) != 0) {
+			dprintf("Error reading attribute %s\n",	path);
+			sysfs_close_attribute(attr);
+			return 0;
+		}
+	}
+			                        
+	if (sysdir->attributes == NULL) {
+		sysdir->attributes = dlist_new_with_delete
+			(sizeof(struct sysfs_attribute), sysfs_del_attribute);
+	}
+	dlist_unshift(sysdir->attributes, attr);
+
+	return 0;
+}
+
+/**
+ * add_subdirectory: open and add subdirectory at path to given directory
+ * @sysdir: directory to add subdir to
+ * @path: path to subdirectory
+ * returns 0 with success and -1 with error.
+ */
+static int add_subdirectory(struct sysfs_directory *sysdir, 
+					const unsigned char *path)
+{
+	struct sysfs_directory *subdir = NULL;
+
+	subdir = sysfs_open_directory(path);
+	if (subdir == NULL) {
+		dprintf("Error opening directory %s\n", path);
+		return -1;
+	}
+	if (sysdir->subdirs == NULL)
+		sysdir->subdirs = dlist_new_with_delete
+			(sizeof(struct sysfs_directory), sysfs_del_directory);
+	dlist_unshift(sysdir->subdirs, subdir);
+	return 0;
+}
+
+/**
+ * add_link: open and add link at path to given directory
+ * @sysdir: directory to add link to
+ * @path: path to link
+ * returns 0 with success and -1 with error.
+ */
+static int add_link(struct sysfs_directory *sysdir, const unsigned char *path)
+{
+	struct sysfs_link *ln = NULL;
+
+	ln = sysfs_open_link(path);
+	if (ln == NULL) {
+		dprintf("Error opening link %s\n", path);
+		return -1;
+	}
+	if (sysdir->links == NULL)
+		sysdir->links = dlist_new_with_delete
+				(sizeof(struct sysfs_link), sysfs_del_link);
+	dlist_unshift(sysdir->links, ln);
+	return 0;
+}
+
+/**
+ * sysfs_read_dir_attributes: grabs attributes for the given directory
  * @sysdir: sysfs directory to open
  * returns 0 with success and -1 with error.
  */
-int sysfs_read_directory(struct sysfs_directory *sysdir)
+int sysfs_read_dir_attributes(struct sysfs_directory *sysdir)
 {
 	DIR *dir = NULL;
 	struct dirent *dirent = NULL;
 	struct stat astats;
-	struct sysfs_attribute *attr = NULL;
-	struct sysfs_directory *subdir = NULL;
-	struct sysfs_link *ln = NULL;
 	unsigned char file_path[SYSFS_PATH_MAX];
 	int retval = 0;
 
@@ -531,54 +662,52 @@ int sysfs_read_directory(struct sysfs_directory *sysdir)
 			dprintf("stat failed\n");
 			continue;
 		}
-		if (S_ISREG(astats.st_mode)) {	
-			attr = sysfs_open_attribute(file_path);
-			if (attr == NULL) {
-				dprintf("Error opening attribute %s\n",
-					file_path);
-				retval = -1;
-				break;
-			}
-			if (attr->method & SYSFS_METHOD_SHOW) {
-				if ((sysfs_read_attribute(attr)) != 0) {
-					dprintf("Error reading attribute %s\n",
-						file_path);
-					sysfs_close_attribute(attr);
-					continue;
-				}
-			}
-			                        
-			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);
-			if (subdir == NULL) {
-				dprintf("Error opening directory %s\n",
-					file_path);
-				retval = -1;
-				break;
-			}
-			if (sysdir->subdirs == NULL)
-				sysdir->subdirs = dlist_new_with_delete
-					(sizeof(struct sysfs_directory),
-							sysfs_del_directory);
-			dlist_unshift(sysdir->subdirs, subdir);
-		} else if (S_ISLNK(astats.st_mode)) {
-			ln = sysfs_open_link(file_path);
-			if (ln == NULL) {
-				dprintf("Error opening link %s\n", file_path);
-				retval = -1;
+		if (S_ISREG(astats.st_mode)) 
+			retval = add_attribute(sysdir, file_path);
+	}
+	closedir(dir);
+	return(retval);
+}
+
+/**
+ * sysfs_read_dir_links: grabs links in a specific directory
+ * @sysdir: sysfs directory to read links
+ * returns 0 with success and -1 with error.
+ */
+int sysfs_read_dir_links(struct sysfs_directory *sysdir)
+{
+	DIR *dir = NULL;
+	struct dirent *dirent = NULL;
+	struct stat astats;
+	unsigned char file_path[SYSFS_PATH_MAX];
+	int retval = 0;
+
+	if (sysdir == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+	dir = opendir(sysdir->path);
+	if (dir == NULL) {
+		dprintf("Error opening directory %s\n", sysdir->path);
+		return -1;
+	}
+	while(((dirent = readdir(dir)) != NULL) && retval == 0) {
+		if (0 == strcmp(dirent->d_name, "."))
+			 continue;
+		if (0 == strcmp(dirent->d_name, ".."))
+			continue;
+		memset(file_path, 0, SYSFS_PATH_MAX);
+		strncpy(file_path, sysdir->path, sizeof(file_path));
+		strncat(file_path, "/", sizeof(file_path));
+		strncat(file_path, dirent->d_name, sizeof(file_path));
+		if ((lstat(file_path, &astats)) != 0) {
+			dprintf("stat failed\n");
+			continue;
+		}
+		if (S_ISLNK(astats.st_mode)) {
+			retval = add_link(sysdir, file_path);
+			if (retval != 0)
 				break;
-			}
-			if (sysdir->links == NULL)
-				sysdir->links = dlist_new_with_delete
-						(sizeof(struct sysfs_link),
-						 		sysfs_del_link);
-			dlist_unshift(sysdir->links, ln);
 		}
 	}
 	closedir(dir);
@@ -586,7 +715,98 @@ int sysfs_read_directory(struct sysfs_directory *sysdir)
 }
 
 /**
- * sysfs_get_directory_attribute: retrieves attribute attrname
+ * sysfs_read_dir_subdirs: grabs subdirs in a specific directory
+ * @sysdir: sysfs directory to read links
+ * returns 0 with success and -1 with error.
+ */
+int sysfs_read_dir_subdirs(struct sysfs_directory *sysdir)
+{
+	DIR *dir = NULL;
+	struct dirent *dirent = NULL;
+	struct stat astats;
+	unsigned char file_path[SYSFS_PATH_MAX];
+	int retval = 0;
+
+	if (sysdir == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+	dir = opendir(sysdir->path);
+	if (dir == NULL) {
+		dprintf("Error opening directory %s\n", sysdir->path);
+		return -1;
+	}
+	while(((dirent = readdir(dir)) != NULL) && retval == 0) {
+		if (0 == strcmp(dirent->d_name, "."))
+			 continue;
+		if (0 == strcmp(dirent->d_name, ".."))
+			continue;
+		memset(file_path, 0, SYSFS_PATH_MAX);
+		strncpy(file_path, sysdir->path, sizeof(file_path));
+		strncat(file_path, "/", sizeof(file_path));
+		strncat(file_path, dirent->d_name, sizeof(file_path));
+		if ((lstat(file_path, &astats)) != 0) {
+			dprintf("stat failed\n");
+			continue;
+		}
+		if (S_ISDIR(astats.st_mode))
+			retval = add_subdirectory(sysdir, file_path);
+	}
+	closedir(dir);
+	return(retval);
+}
+
+/**
+ * sysfs_read_directory: grabs attributes, links, and subdirectories
+ * @sysdir: sysfs directory to open
+ * returns 0 with success and -1 with error.
+ */
+int sysfs_read_directory(struct sysfs_directory *sysdir)
+{
+	DIR *dir = NULL;
+	struct dirent *dirent = NULL;
+	struct stat astats;
+	unsigned char file_path[SYSFS_PATH_MAX];
+	int retval = 0;
+
+	if (sysdir == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+	dir = opendir(sysdir->path);
+	if (dir == NULL) {
+		dprintf("Error opening directory %s\n", sysdir->path);
+		return -1;
+	}
+	while(((dirent = readdir(dir)) != NULL) && retval == 0) {
+		if (0 == strcmp(dirent->d_name, "."))
+			 continue;
+		if (0 == strcmp(dirent->d_name, ".."))
+			continue;
+		memset(file_path, 0, SYSFS_PATH_MAX);
+		strncpy(file_path, sysdir->path, sizeof(file_path));
+		strncat(file_path, "/", sizeof(file_path));
+		strncat(file_path, dirent->d_name, sizeof(file_path));
+		if ((lstat(file_path, &astats)) != 0) {
+			dprintf("stat failed\n");
+			continue;
+		}
+		if (S_ISDIR(astats.st_mode)) 
+			retval = add_subdirectory(sysdir, file_path);
+
+		else if (S_ISLNK(astats.st_mode))
+			retval = add_link(sysdir, file_path);
+
+		else if (S_ISREG(astats.st_mode))
+			retval = add_attribute(sysdir, file_path);
+	}
+	closedir(dir);
+	return(retval);
+}
+
+/**
+ * sysfs_get_directory_attribute: retrieves attribute attrname from current
+ *	directory only
  * @dir: directory to retrieve attribute from
  * @attrname: name of attribute to look for
  * returns sysfs_attribute if found and NULL if not found
@@ -594,27 +814,38 @@ int sysfs_read_directory(struct sysfs_directory *sysdir)
 struct sysfs_attribute *sysfs_get_directory_attribute
 			(struct sysfs_directory *dir, unsigned char *attrname)
 {
-	struct sysfs_directory *sdir = NULL;
 	struct sysfs_attribute *attr = NULL;
+	unsigned char new_path[SYSFS_PATH_MAX];
 	
 	if (dir == NULL || attrname == NULL) {
 		errno = EINVAL;
 		return NULL;
 	}
-	
-	attr = (struct sysfs_attribute *)dlist_find_custom(dir->attributes,
-		attrname, dir_attribute_name_equal);
-	if (attr != NULL)
+
+	if (dir->attributes == NULL) 
+		if ((sysfs_read_dir_attributes(dir) != 0) 
+		    || (dir->attributes == NULL))
+			return NULL;
+
+	attr = (struct sysfs_attribute *)dlist_find_custom
+			(dir->attributes, attrname, dir_attribute_name_equal);
+	if (attr != NULL) {
+		/*
+		 * don't read here since we would have read the attribute in 
+		 * in the routine that called this routine
+		 */ 
 		return attr;
-	
-	if (dir->subdirs != NULL) {
-		dlist_for_each_data(dir->subdirs, sdir, 
-					struct sysfs_directory) {
-			if (sdir->attributes == NULL)
-				continue;
-			attr = sysfs_get_directory_attribute(sdir, attrname);
-			if (attr != NULL)
-				return attr;
+	} else {
+		memset(new_path, 0, SYSFS_PATH_MAX);
+		strcpy(new_path, dir->path);
+		strcat(new_path, "/");
+		strcat(new_path, attrname);
+		if ((sysfs_path_is_file(new_path)) == 0) {
+		 	if ((add_attribute(dir, new_path)) == 0) {
+				attr = (struct sysfs_attribute *)dlist_find_custom
+					(dir->attributes, attrname, dir_attribute_name_equal);
+			}
+			return attr;
 		}
 	}
 	return NULL;
@@ -633,6 +864,10 @@ struct sysfs_link *sysfs_get_directory_link
 		errno = EINVAL;
 		return NULL;
 	}
+	if (dir->links == NULL)
+		if ((sysfs_read_dir_links(dir) != 0) || (dir->links == NULL))
+			return NULL;
+
 	return (struct sysfs_link *)dlist_find_custom(dir->links,
 		linkname, dir_link_name_equal);
 }
@@ -648,10 +883,15 @@ struct sysfs_directory *sysfs_get_subdirectory(struct sysfs_directory *dir,
 {
 	struct sysfs_directory *sub = NULL, *cursub = NULL;
 
-	if (dir == NULL || dir->subdirs == NULL || subname == NULL) {
+	if (dir == NULL || subname == NULL) {
 		errno = EINVAL;
 		return NULL;
 	}
+
+	if (dir->subdirs == NULL)
+		if (sysfs_read_dir_subdirs(dir) != 0)
+			return NULL;
+
 	sub = (struct sysfs_directory *)dlist_find_custom(dir->subdirs,
 		subname, dir_subdir_name_equal);
 	if (sub != NULL) 
@@ -660,8 +900,12 @@ struct sysfs_directory *sysfs_get_subdirectory(struct sysfs_directory *dir,
 	if (dir->subdirs != NULL) {
 		dlist_for_each_data(dir->subdirs, cursub, 
 					struct sysfs_directory) {
-			if (cursub->subdirs == NULL)
-				continue;
+			if (cursub->subdirs == NULL) {
+				if (sysfs_read_dir_subdirs(cursub) != 0)
+					continue;
+				if (cursub->subdirs == NULL)
+					continue;
+			}
 			sub = sysfs_get_subdirectory(cursub, subname);
 			if (sub != NULL)
 				return sub;
@@ -682,7 +926,7 @@ struct sysfs_link *sysfs_get_subdirectory_link(struct sysfs_directory *dir,
 	struct sysfs_directory *cursub = NULL;
 	struct sysfs_link *ln = NULL;
 
-	if (dir == NULL || dir->links == NULL || linkname == NULL) {
+	if (dir == NULL || linkname == NULL) {
 		errno = EINVAL;
 		return NULL;
 	}
@@ -691,14 +935,13 @@ struct sysfs_link *sysfs_get_subdirectory_link(struct sysfs_directory *dir,
 	if (ln != NULL)
 		return ln;
 
-	if (dir->subdirs == NULL)
-		return NULL;
+	if (dir->subdirs == NULL) 
+		if (sysfs_read_dir_subdirs(dir) != 0)
+			return NULL;
 
 	if (dir->subdirs != NULL) {
 		dlist_for_each_data(dir->subdirs, cursub, 
 						struct sysfs_directory) {
-			if (cursub->subdirs == NULL)
-				continue;
 			ln = sysfs_get_subdirectory_link(cursub, linkname);
 			if (ln != NULL)
 				return ln;