X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=libudev%2Flibudev-device.c;h=b841745991effca0a32ac69ee7b1d70c36129d3f;hp=96cc2dba1c653808dd706055bf8576bfc3ff0031;hb=3a19299202b5d34b89d5910fde25e8a4cfa2b31a;hpb=a5710160377a85e7c78601e2c45049b392891436

diff --git a/libudev/libudev-device.c b/libudev/libudev-device.c
index 96cc2dba1..b84174599 100644
--- a/libudev/libudev-device.c
+++ b/libudev/libudev-device.c
@@ -23,6 +23,21 @@
 #include "libudev.h"
 #include "libudev-private.h"
 
+/**
+ * SECTION:libudev-device
+ * @short_description: kernel sys devices
+ *
+ * Representation of kernel sys devices. Devices are uniquely identified
+ * by their syspath, every device has exactly one path in the kernel sys
+ * filesystem. Devices usually belong to a kernel subsystem, and and have
+ * a unique name inside that subsystem.
+ */
+
+/**
+ * udev_device:
+ *
+ * Opaque object representing one kernel sys device.
+ */
 struct udev_device {
 	struct udev *udev;
 	struct udev_device *parent_device;
@@ -36,6 +51,7 @@ struct udev_device {
 	char *driver;
 	char *action;
 	char *devpath_old;
+	char *sysname_old;
 	char *knodename;
 	char **envp;
 	char *monitor_buf;
@@ -61,16 +77,6 @@ struct udev_device {
 	unsigned int ignore_remove:1;
 };
 
-static size_t devpath_to_db_path(struct udev *udev, const char *devpath, char *filename, size_t len)
-{
-	char *s;
-	size_t l;
-
-	s = filename;
-	l = util_strpcpyl(&s, len, udev_get_dev_path(udev), "/.udev/db/", NULL);
-	return util_path_encode(devpath, s, l);
-}
-
 int udev_device_read_db(struct udev_device *udev_device)
 {
 	struct stat stats;
@@ -78,7 +84,8 @@ int udev_device_read_db(struct udev_device *udev_device)
 	char line[UTIL_LINE_SIZE];
 	FILE *f;
 
-	devpath_to_db_path(udev_device->udev, udev_device->devpath, filename, sizeof(filename));
+	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev_device->udev), "/.udev/db/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 
 	if (lstat(filename, &stats) != 0) {
 		dbg(udev_device->udev, "no db file to read %s: %m\n", filename);
@@ -116,7 +123,7 @@ int udev_device_read_db(struct udev_device *udev_device)
 				next = &next[1];
 			}
 			util_strscpyl(devlink, sizeof(devlink), udev_get_dev_path(udev_device->udev), "/", lnk, NULL);
-			udev_device_add_devlink(udev_device, devlink);
+			udev_device_add_devlink(udev_device, devlink, 0);
 		}
 		info(udev_device->udev, "device %p filled with db symlink data '%s'\n", udev_device, udev_device->devnode);
 		return 0;
@@ -143,7 +150,7 @@ int udev_device_read_db(struct udev_device *udev_device)
 			break;
 		case 'S':
 			util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev_device->udev), "/", val, NULL);
-			udev_device_add_devlink(udev_device, filename);
+			udev_device_add_devlink(udev_device, filename, 0);
 			break;
 		case 'L':
 			udev_device_set_devlink_priority(udev_device, atoi(val));
@@ -255,7 +262,7 @@ struct udev_device *udev_device_new(struct udev *udev)
  * @syspath: sys device path including sys directory
  *
  * Create new udev device, and fill in information from the sys
- * device and the udev database entry. The sypath is the absolute
+ * device and the udev database entry. The syspath is the absolute
  * path to the device, including the sys mount point.
  *
  * The initial refcount is 1, and needs to be decremented to
@@ -296,25 +303,7 @@ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *
 	util_strscpy(path, sizeof(path), syspath);
 	util_resolve_sys_link(udev, path, sizeof(path));
 
-	/* try to resolve the silly block layout if needed */
-	if (strncmp(&path[len], "/block/", 7) == 0) {
-		char block[UTIL_PATH_SIZE];
-		char part[UTIL_PATH_SIZE];
-
-		util_strscpy(block, sizeof(block), path);
-		pos = strrchr(block, '/');
-		if (pos == NULL)
-			return NULL;
-		util_strscpy(part, sizeof(part), pos);
-		pos[0] = '\0';
-		if (util_resolve_sys_link(udev, block, sizeof(block)) == 0)
-			util_strscpyl(path, sizeof(path), block, part, NULL);
-	}
-
-	/* path exists in sys */
-	if (strncmp(&syspath[len], "/devices/", 9) == 0 ||
-	    strncmp(&syspath[len], "/class/", 7) == 0 ||
-	    strncmp(&syspath[len], "/block/", 7) == 0) {
+	if (strncmp(&syspath[len], "/devices/", 9) == 0) {
 		char file[UTIL_PATH_SIZE];
 
 		/* all "devices" require a "uevent" file */
@@ -341,13 +330,27 @@ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *
 	return udev_device;
 }
 
+/**
+ * udev_device_new_from_devnum:
+ * @udev: udev library context
+ * @type: char or block device
+ * @devnum: device major/minor number
+ *
+ * Create new udev device, and fill in information from the sys
+ * device and the udev database entry. The device is looked up
+ * by its major/minor number. Character and block device numbers
+ * are not unique across the two types, they do not share the same
+ * range of numbers.
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
 struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 {
 	char path[UTIL_PATH_SIZE];
 	const char *type_str;
-	struct udev_enumerate *udev_enumerate;
-	struct udev_list_entry *list_entry;
-	struct udev_device *device = NULL;
 
 	if (type == 'b')
 		type_str = "block";
@@ -356,42 +359,28 @@ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, de
 	else
 		return NULL;
 
-	/* /sys/dev/{block,char}/<maj>:<min> link */
-	snprintf(path, sizeof(path), "%s/dev/%s/%u:%u", udev_get_sys_path(udev),
-		 type_str, major(devnum), minor(devnum));
-	if (util_resolve_sys_link(udev, path, sizeof(path)) == 0)
-		return udev_device_new_from_syspath(udev, path);
-
-	udev_enumerate = udev_enumerate_new(udev);
-	if (udev_enumerate == NULL)
-		return NULL;
-
-	/* fallback to search sys devices for the major/minor */
-	if (type == 'b')
-		udev_enumerate_add_match_subsystem(udev_enumerate, "block");
-	else if (type == 'c')
-		udev_enumerate_add_nomatch_subsystem(udev_enumerate, "block");
-	udev_enumerate_scan_devices(udev_enumerate);
-	udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(udev_enumerate)) {
-		struct udev_device *device_loop;
-
-		device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
-		if (device_loop != NULL) {
-			if (udev_device_get_devnum(device_loop) == devnum) {
-				if (type == 'b' && strcmp(udev_device_get_subsystem(device_loop), "block") != 0)
-					continue;
-				if (type == 'c' && strcmp(udev_device_get_subsystem(device_loop), "block") == 0)
-					continue;
-				device = device_loop;
-				break;
-			}
-			udev_device_unref(device_loop);
-		}
-	}
-	udev_enumerate_unref(udev_enumerate);
-	return device;
+	/* use /sys/dev/{block,char}/<maj>:<min> link */
+	snprintf(path, sizeof(path), "%s/dev/%s/%u:%u",
+		 udev_get_sys_path(udev), type_str, major(devnum), minor(devnum));
+	return udev_device_new_from_syspath(udev, path);
 }
 
+/**
+ * udev_device_new_from_subsystem_sysname:
+ * @udev: udev library context
+ * @subsystem: the subsystem of the device
+ * @sysname: the name of the device
+ *
+ * Create new udev device, and fill in information from the sys
+ * device and the udev database entry. The device is looked up
+ * by the subsystem and name string of the device, like "mem",
+ * "zero", or "block", "sda".
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
 struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 {
 	char path_full[UTIL_PATH_SIZE];
@@ -468,20 +457,9 @@ static struct udev_device *device_new_from_parent(struct udev_device *udev_devic
 	char path[UTIL_PATH_SIZE];
 	const char *subdir;
 
-	/* follow "device" link in deprecated sys layout */
-	if (strncmp(udev_device->devpath, "/class/", 7) == 0 ||
-	    strncmp(udev_device->devpath, "/block/", 7) == 0) {
-		util_strscpyl(path, sizeof(path), udev_device->syspath, "/device", NULL);
-		if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0) {
-			udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
-			if (udev_device_parent != NULL)
-				return udev_device_parent;
-		}
-	}
-
 	util_strscpy(path, sizeof(path), udev_device->syspath);
 	subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
-	while (1) {
+	for (;;) {
 		char *pos;
 
 		pos = strrchr(subdir, '/');
@@ -495,6 +473,25 @@ static struct udev_device *device_new_from_parent(struct udev_device *udev_devic
 	return NULL;
 }
 
+/**
+ * udev_device_get_parent:
+ * @udev_device: the device to start searching from
+ *
+ * Find the next parent device, and fill in information from the sys
+ * device and the udev database entry.
+ *
+ * The returned the device is not referenced. It is attached to the
+ * child device, and will be cleaned up when the child device
+ * is cleaned up.
+ *
+ * It is not necessarily just the upper level directory, empty or not
+ * recognized sys directories are ignored.
+ *
+ * It can be called as many times as needed, without caring about
+ * references.
+ *
+ * Returns: a new udev device, or #NULL, if it no parent exist.
+ **/
 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 {
 	if (udev_device == NULL)
@@ -508,6 +505,28 @@ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 	return udev_device->parent_device;
 }
 
+/**
+ * udev_device_get_parent_with_subsystem_devtype:
+ * @udev_device: udev device to start searching from
+ * @subsystem: the subsystem of the device
+ * @devtype: the type (DEVTYPE) of the device
+ *
+ * Find the next parent device, with a matching subsystem and devtype
+ * value, and fill in information from the sys device and the udev
+ * database entry.
+ *
+ * If devtype is #NULL, only subsystem is checked, and any devtype will
+ * match.
+ *
+ * The returned the device is not referenced. It is attached to the
+ * child device, and will be cleaned up when the child device
+ * is cleaned up.
+ *
+ * It can be called as many times as needed, without caring about
+ * references.
+ *
+ * Returns: a new udev device, or #NULL if no matching parent exists.
+ **/
 struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype)
 {
 	struct udev_device *parent;
@@ -591,6 +610,7 @@ void udev_device_unref(struct udev_device *udev_device)
 	free(udev_device->action);
 	free(udev_device->driver);
 	free(udev_device->devpath_old);
+	free(udev_device->sysname_old);
 	free(udev_device->knodename);
 	udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
 	free(udev_device->envp);
@@ -631,6 +651,12 @@ const char *udev_device_get_syspath(struct udev_device *udev_device)
 	return udev_device->syspath;
 }
 
+/**
+ * udev_device_get_sysname:
+ * @udev_device: udev device
+ *
+ * Returns: the sys name of the device device
+ **/
 const char *udev_device_get_sysname(struct udev_device *udev_device)
 {
 	if (udev_device == NULL)
@@ -638,6 +664,12 @@ const char *udev_device_get_sysname(struct udev_device *udev_device)
 	return udev_device->sysname;
 }
 
+/**
+ * udev_device_get_sysnum:
+ * @udev_device: udev device
+ *
+ * Returns: the trailing number of of the device name
+ **/
 const char *udev_device_get_sysnum(struct udev_device *udev_device)
 {
 	if (udev_device == NULL)
@@ -680,7 +712,7 @@ const char *udev_device_get_subsystem(struct udev_device *udev_device)
 		return NULL;
 	if (!udev_device->subsystem_set) {
 		udev_device->subsystem_set = 1;
-		/* read "subsytem" link */
+		/* read "subsystem" link */
 		if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
 			udev_device_set_subsystem(udev_device, subsystem);
 			return udev_device->subsystem;
@@ -790,6 +822,12 @@ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device
 	return udev_list_get_entry(&udev_device->properties_list);
 }
 
+/**
+ * udev_device_get_driver:
+ * @udev_device: udev device
+ *
+ * Returns: the driver string, or #NULL if there is no driver attached.
+ **/
 const char *udev_device_get_driver(struct udev_device *udev_device)
 {
 	char driver[UTIL_NAME_SIZE];
@@ -804,6 +842,12 @@ const char *udev_device_get_driver(struct udev_device *udev_device)
 	return udev_device->driver;
 }
 
+/**
+ * udev_device_get_devnum:
+ * @udev_device: udev device
+ *
+ * Returns: the device major/minor number.
+ **/
 dev_t udev_device_get_devnum(struct udev_device *udev_device)
 {
 	if (udev_device == NULL)
@@ -813,6 +857,16 @@ dev_t udev_device_get_devnum(struct udev_device *udev_device)
 	return udev_device->devnum;
 }
 
+/**
+ * udev_device_get_action:
+ * @udev_device: udev device
+ *
+ * This is only valid if the device was received through a monitor. Devices read from
+ * sys do not have an action string. Usual actions are: add, remove, change, online,
+ * offline.
+ *
+ * Returns: the kernel action value, or #NULL if there is no action value available.
+ **/
 const char *udev_device_get_action(struct udev_device *udev_device)
 {
 	if (udev_device == NULL)
@@ -820,6 +874,15 @@ const char *udev_device_get_action(struct udev_device *udev_device)
 	return udev_device->action;
 }
 
+/**
+ * udev_device_get_devnum:
+ * @udev_device: udev device
+ *
+ * This is only valid if the device was received through a monitor. Devices read from
+ * sys do not have a sequence number.
+ *
+ * Returns: the kernel event sequence number, or 0 if there is no sequence number available.
+ **/
 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 {
 	if (udev_device == NULL)
@@ -827,6 +890,16 @@ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 	return udev_device->seqnum;
 }
 
+/**
+ * udev_device_get_sysattr_value:
+ * @udev_device: udev device
+ * @sysattr: attribute name
+ *
+ * The retrieved value is cached in the device. Repeated calls will return the same
+ * value and not open the attribute again.
+ *
+ * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value.
+ **/
 const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
 {
 	struct udev_list_entry *list_entry;
@@ -986,11 +1059,16 @@ int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode
 	return 0;
 }
 
-int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink)
+int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink, int unique)
 {
+	struct udev_list_entry *list_entry;
+
 	udev_device->devlinks_uptodate = 0;
-	if (udev_list_entry_add(udev_device->udev, &udev_device->devlinks_list, devlink, NULL, 1, 0) == NULL)
+	list_entry = udev_list_entry_add(udev_device->udev, &udev_device->devlinks_list, devlink, NULL, 1, 0);
+	if (list_entry == NULL)
 		return -ENOMEM;
+	if (unique)
+		udev_list_entry_set_flag(list_entry, 1);
 	return 0;
 }
 
@@ -1011,7 +1089,7 @@ struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device
 
 struct udev_list_entry *udev_device_add_property_from_string(struct udev_device *udev_device, const char *property)
 {
-	char name[UTIL_PATH_SIZE];
+	char name[UTIL_LINE_SIZE];
 	char *val;
 
 	util_strscpy(name, sizeof(name), property);
@@ -1025,6 +1103,13 @@ struct udev_list_entry *udev_device_add_property_from_string(struct udev_device
 	return udev_device_add_property(udev_device, name, val);
 }
 
+/**
+ * udev_device_get_property_value:
+ * @udev_device: udev device
+ * @key: property name
+ *
+ * Returns: the value of a device property, or #NULL if there is no such property.
+ **/
 const char *udev_device_get_property_value(struct udev_device *udev_device, const char *key)
 {
 	struct udev_list_entry *list_entry;
@@ -1065,17 +1150,25 @@ static int update_envp_monitor_buf(struct udev_device *udev_device)
 	s = udev_device->monitor_buf;
 	l = MONITOR_BUF_SIZE;
 	udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
+		const char *key;
+
+		key = udev_list_entry_get_name(list_entry);
+		/* skip private variables */
+		if (key[0] == '.')
+			continue;
+
 		/* add string to envp array */
 		udev_device->envp[i++] = s;
 		if (i+1 >= ENVP_SIZE)
 			return -EINVAL;
 
 		/* add property string to monitor buffer */
-		l = util_strpcpyl(&s, l, udev_list_entry_get_name(list_entry), "=",
-				  udev_list_entry_get_value(list_entry), NULL);
+		l = util_strpcpyl(&s, l, key, "=", udev_list_entry_get_value(list_entry), NULL);
 		if (l == 0)
 			return -EINVAL;
+		/* advance past the trailing '\0' that util_strpcpyl() guarantees */
 		s++;
+		l--;
 	}
 	udev_device->envp[i] = NULL;
 	udev_device->monitor_buf_len = s - udev_device->monitor_buf;
@@ -1130,13 +1223,39 @@ const char *udev_device_get_devpath_old(struct udev_device *udev_device)
 
 int udev_device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
 {
+	const char *pos;
+	size_t len;
+
+	free(udev_device->devpath_old);
 	udev_device->devpath_old = strdup(devpath_old);
 	if (udev_device->devpath_old == NULL)
 		return -ENOMEM;
 	udev_device_add_property(udev_device, "DEVPATH_OLD", udev_device->devpath_old);
+
+	pos = strrchr(udev_device->devpath_old, '/');
+	if (pos == NULL)
+		return -EINVAL;
+	udev_device->sysname_old = strdup(&pos[1]);
+	if (udev_device->sysname_old == NULL)
+		return -ENOMEM;
+
+	/* some devices have '!' in their name, change that to '/' */
+	len = 0;
+	while (udev_device->sysname_old[len] != '\0') {
+		if (udev_device->sysname_old[len] == '!')
+			udev_device->sysname_old[len] = '/';
+		len++;
+	}
 	return 0;
 }
 
+const char *udev_device_get_sysname_old(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->sysname_old;
+}
+
 const char *udev_device_get_knodename(struct udev_device *udev_device)
 {
 	return udev_device->knodename;
@@ -1144,9 +1263,11 @@ const char *udev_device_get_knodename(struct udev_device *udev_device)
 
 int udev_device_set_knodename(struct udev_device *udev_device, const char *knodename)
 {
+	free(udev_device->knodename);
 	udev_device->knodename = strdup(knodename);
 	if (udev_device->knodename == NULL)
 		return -ENOMEM;
+	udev_device_add_property(udev_device, "DEVNAME", udev_device->knodename);
 	return 0;
 }