chiark / gitweb /
[PATCH] big libsysfs diet (pre 2.0 version)
[elogind.git] / libsysfs / sysfs_device.c
index 185b5cf..7087730 100644 (file)
@@ -3,7 +3,7 @@
  *
  * Generic device utility functions for libsysfs
  *
- * Copyright (C) 2003 International Business Machines, Inc.
+ * Copyright (C) IBM Corp. 2003-2005
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
 #include "sysfs.h"
 
 /**
- * sysfs_close_device: closes and cleans up a device
- * @dev = device to clean up
+ * get_dev_driver: fills in the dev->driver_name field 
+ * Returns 0 on SUCCESS and -1 on error
  */
-void sysfs_close_device(struct sysfs_device *dev)
+static int get_dev_driver(struct sysfs_device *dev)
 {
-       if (dev != NULL) {
-               dev->next = NULL;
-               dev->driver = NULL;
-               if (dev->directory != NULL)
-                       sysfs_close_directory(dev->directory);
-               dev->children = NULL;
-               free(dev);
+       struct dlist *drvlist;
+       char path[SYSFS_PATH_MAX];
+       char devpath[SYSFS_PATH_MAX];
+       char *drv = NULL, *c;
+
+       if (!dev) {
+               errno = EINVAL;
+               return -1;
        }
+
+       memset(path, 0, SYSFS_PATH_MAX);
+       memset(devpath, 0, SYSFS_PATH_MAX);
+       safestrcpymax(path, dev->path, SYSFS_PATH_MAX);
+       safestrcatmax(path, "/driver", SYSFS_PATH_MAX);
+       if (!sysfs_path_is_link(path)) {
+               if (!sysfs_get_link(path, devpath, SYSFS_PATH_MAX)) {
+                       if (sysfs_get_name_from_path(devpath, 
+                                       dev->driver_name, SYSFS_NAME_LEN))
+                               return -1;
+               }
+               return 0;
+       }
+
+       /*
+        * Devices on on earlier kernels do not have the "driver" link.
+        * Look it up in the bus directory.
+        */
+       if (dev->bus[0] == '\0')
+               return -1;
+       memset(path, 0, SYSFS_PATH_MAX);
+       memset(devpath, 0, SYSFS_PATH_MAX);
+       safestrcpy(path, dev->path);
+       c = strstr(path, SYSFS_DEVICES_NAME);
+       if (c == NULL) {
+               dprintf("Invalid path to device - %s\n", dev->path);
+               return -1;
+       } else
+               *c = '\0';
+       safestrcat(path, SYSFS_BUS_NAME);
+       safestrcat(path, "/");
+       safestrcat(path, dev->bus);
+       safestrcat(path, "/");
+       safestrcat(path, SYSFS_DRIVERS_NAME);
+
+       drvlist = sysfs_open_directory_list(path);
+       if (drvlist) {
+               dlist_for_each_data(drvlist, drv, char) {
+                       safestrcpy(devpath, path);
+                       safestrcat(devpath, "/");
+                       safestrcat(devpath, drv);
+                       safestrcat(devpath, "/");
+                       safestrcat(devpath, dev->bus_id);
+                       if (sysfs_path_is_link(devpath) == 0) {
+                               safestrcpy(dev->driver_name, drv);
+                               sysfs_close_list(drvlist);
+                               return 0;
+                       }
+               }
+               sysfs_close_list(drvlist);
+       }
+       return -1;
 }
 
 /**
- * alloc_device: allocates and initializes device structure
- * returns struct sysfs_device
+ * sysfs_get_device_bus: retrieves the bus name the device is on, checks path 
+ *     to bus' link to make sure it has correct device.
+ * @dev: device to get busname.
+ * returns 0 with success and -1 with error.
  */
-static struct sysfs_device *alloc_device(void)
+int sysfs_get_device_bus(struct sysfs_device *dev)
 {
-       return (struct sysfs_device *)calloc(1, sizeof(struct sysfs_device));
+       char devpath[SYSFS_PATH_MAX];
+       char subsys[SYSFS_NAME_LEN];
+       char path[SYSFS_PATH_MAX];
+       char target[SYSFS_PATH_MAX];
+       char *bus = NULL, *c;
+       struct dlist *buslist;
+
+       if (!dev) {
+               errno = EINVAL;
+               return -1;
+       }
+
+       memset(path, 0, SYSFS_PATH_MAX);
+       memset(devpath, 0, SYSFS_PATH_MAX);
+       safestrcpymax(path, dev->path, SYSFS_PATH_MAX);
+       safestrcatmax(path, "/bus", SYSFS_PATH_MAX);
+       if (!sysfs_path_is_link(path)) {
+               if (!sysfs_get_link(path, devpath, SYSFS_PATH_MAX)) {
+                       if (sysfs_get_name_from_path(devpath, 
+                                       dev->bus, SYSFS_NAME_LEN))
+                               return -1;
+               }
+               return 0;
+       }
+
+       /*
+        * Devices on on earlier kernels do not have the "bus" link.
+        * Look it up in the bus directory.
+        */
+       memset(subsys, 0, SYSFS_NAME_LEN);
+       safestrcpy(subsys, dev->path);
+       c = strstr(subsys, SYSFS_DEVICES_NAME);
+       if (c == NULL) {
+               dprintf("Invalid path to device - %s\n", dev->path);
+               return -1;
+       } else 
+               *c = '\0';
+       safestrcat(subsys, SYSFS_BUS_NAME);
+       buslist = sysfs_open_directory_list(subsys);
+       if (buslist) {
+               dlist_for_each_data(buslist, bus, char) {
+                       memset(path, 0, SYSFS_PATH_MAX);
+                       safestrcpy(path, subsys);
+                       safestrcat(path, "/");
+                       safestrcat(path, bus);
+                       safestrcat(path, "/");
+                       safestrcat(path, SYSFS_DEVICES_NAME);
+                       safestrcat(path, "/");
+                       safestrcat(path, dev->bus_id);
+                       if ((sysfs_path_is_link(path)) == 0) {
+                               memset(target, 0, SYSFS_PATH_MAX);
+                               if (sysfs_get_link(path, target, 
+                                               SYSFS_PATH_MAX)) {
+                                       dprintf("Error getting link target\n");
+                                       sysfs_close_list(buslist);
+                                       return -1;
+                               }
+                               if (!(strncmp(target, dev->path, 
+                                                       SYSFS_PATH_MAX))) {
+                                       safestrcpy(dev->bus, bus);
+                                       sysfs_close_list(buslist);
+                                       return 0;
+                               }
+                       }
+               }
+               sysfs_close_list(buslist);
+       }
+       return -1;
 }
 
 /**
- * sysfs_get_device_attr: searches dev's attributes by name
- * @dev: device to look through
- * @name: attribute name to get
- * returns sysfs_attribute reference with success or NULL with error.
+ * sysfs_close_device_tree: closes every device in the supplied tree, 
+ *     closing children only.
+ * @devroot: device root of tree.
  */
-struct sysfs_attribute *sysfs_get_device_attr(struct sysfs_device *dev,
-                                               const char *name)
+void sysfs_close_device_tree(struct sysfs_device *devroot)
 {
-       struct sysfs_attribute *cur = NULL;
-       char attrname[SYSFS_NAME_LEN];
+       if (devroot) {
+               if (devroot->children) {
+                       struct sysfs_device *child = NULL;
 
-       if (dev == NULL || dev->directory == NULL || name == NULL) {
-               errno = EINVAL;
-               return NULL;
+                       dlist_for_each_data(devroot->children, child,
+                                       struct sysfs_device) {
+                               sysfs_close_device_tree(child);
+                       }
+               }
+               sysfs_close_device(devroot);
        }
-       for (cur = dev->directory->attributes; cur != NULL; cur = cur->next) {
-               if ((sysfs_get_name_from_path(cur->path, attrname, 
-                   SYSFS_NAME_LEN)) != 0) 
-                       continue;
-               if (strcmp(name, attrname) != 0)
-                       continue;
+}
 
-               return cur;
+/**
+ * sysfs_close_device: closes and cleans up a device
+ * @dev = device to clean up
+ */
+void sysfs_close_device(struct sysfs_device *dev)
+{
+       if (dev) {
+               if (dev->parent)
+                       sysfs_close_device(dev->parent);
+               if (dev->children && dev->children->count)
+                       dlist_destroy(dev->children);
+               if (dev->attrlist)
+                       dlist_destroy(dev->attrlist);
+               free(dev);
        }
+}
 
-       return NULL;
+/**
+ * alloc_device: allocates and initializes device structure
+ * returns struct sysfs_device
+ */
+static struct sysfs_device *alloc_device(void)
+{
+       return (struct sysfs_device *) calloc(1, sizeof(struct sysfs_device));
 }
 
 /**
- * sysfs_open_device: opens and populates device structure
+ * sysfs_open_device_path: opens and populates device structure
  * @path: path to device, this is the /sys/devices/ path
  * returns sysfs_device structure with success or NULL with error
  */
-struct sysfs_device *sysfs_open_device(const char *path)
+struct sysfs_device *sysfs_open_device_path(const char *path)
 {
-       struct sysfs_device *dev = NULL;
-       struct sysfs_directory *sdir = NULL;
-       char *p = NULL;
+       struct sysfs_device *dev;
 
-       if (path == NULL) {
+       if (!path) {
                errno = EINVAL;
                return NULL;
        }
-       dev = alloc_device();   
-       if (dev == NULL) {
-               dprintf(stderr, "Error allocating device at %s\n", path);
+       if (sysfs_path_is_dir(path)) {
+               dprintf("Incorrect path to device: %s\n", path);
+               return NULL;
+       }
+       dev = alloc_device();
+       if (!dev) {
+               dprintf("Error allocating device at %s\n", path);
                return NULL;
        }
-       sdir = sysfs_open_directory(path);
-       if (sdir == NULL) {
-               dprintf(stderr, "Invalid device at %s\n", path);
+       if (sysfs_get_name_from_path(path, dev->bus_id, SYSFS_NAME_LEN)) {
                errno = EINVAL;
+               dprintf("Error getting device bus_id\n");
                sysfs_close_device(dev);
                return NULL;
        }
-       if ((sysfs_read_directory(sdir)) != 0) {
-               dprintf(stderr, "Error reading device directory at %s\n", path);
-               sysfs_close_directory(sdir);
+       safestrcpy(dev->path, path);
+       if (sysfs_remove_trailing_slash(dev->path)) {
+               dprintf("Invalid path to device %s\n", dev->path);
                sysfs_close_device(dev);
                return NULL;
        }
-       dev->directory = sdir;
-       sysfs_get_name_from_path(sdir->path, dev->bus_id, SYSFS_NAME_LEN);
-       /* get device name */
-       p = sysfs_get_value_from_attributes(sdir->attributes,   
-                                                       SYSFS_NAME_ATTRIBUTE);
-       if (p != NULL) {
-               strncpy(dev->name, p, SYSFS_NAME_LEN);
-               p = dev->name + strlen(dev->name) - 1;
-               if ((strlen(dev->name) > 0) && *p == '\n')
-                       *p = '\0';
+       /*
+        * The "name" attribute no longer exists... return the device's
+        * sysfs representation instead, in the "dev->name" field, which
+        * implies that the dev->name and dev->bus_id contain same data.
+        */
+       safestrcpy(dev->name, dev->bus_id);
+
+       if (sysfs_get_device_bus(dev))
+               dprintf("Could not get device bus\n");
+
+       if (get_dev_driver(dev)) {
+               dprintf("Could not get device %s's driver\n", dev->bus_id);
+               safestrcpy(dev->driver_name, SYSFS_UNKNOWN);
        }
 
        return dev;
 }
 
 /**
- * sysfs_close_device_tree: closes every device in the supplied tree, 
- *     closing children only.
- * @devroot: device root of tree.
+ * sysfs_get_device_attr: searches dev's attributes by name
+ * @dev: device to look through
+ * @name: attribute name to get
+ * returns sysfs_attribute reference with success or NULL with error.
  */
-void sysfs_close_device_tree(struct sysfs_device *devroot)
+struct sysfs_attribute *sysfs_get_device_attr(struct sysfs_device *dev,
+                                               const char *name)
 {
-       if (devroot != NULL) {
-               if (devroot->children != NULL) {
-                       struct sysfs_device *child = NULL, *next = NULL;
-       
-                       for (child = devroot->children; child != NULL;
-                            child = next) {
-                               next = child->next;
-                               sysfs_close_device_tree(child);
-                       }
-               }
-               sysfs_close_device(devroot);
+       if (!dev || !name) {
+               errno = EINVAL;
+               return NULL;
+       }
+       return get_attribute(dev, (char *)name);
+}
+
+/**
+ * sysfs_get_device_attributes: gets list of device attributes
+ * @dev: device whose attributes list is needed
+ * returns dlist of attributes on success or NULL on error
+ */
+struct dlist *sysfs_get_device_attributes(struct sysfs_device *dev)
+{
+       if (!dev) {
+               errno = EINVAL;
+               return NULL;
+       }
+       return get_attributes_list(dev);
+}
+
+/**
+ * get_device_absolute_path: looks up the bus the device is on, gets 
+ *             absolute path to the device
+ * @device: device for which path is needed
+ * @path: buffer to store absolute path
+ * @psize: size of "path"
+ * Returns 0 on success -1 on failure
+ */
+static int get_device_absolute_path(const char *device,        const char *bus, 
+                               char *path, size_t psize)
+{
+       char bus_path[SYSFS_PATH_MAX];
+
+       if (!device || !path) {
+               errno = EINVAL;
+               return -1;
        }
+
+       memset(bus_path, 0, SYSFS_PATH_MAX);
+       if (sysfs_get_mnt_path(bus_path, SYSFS_PATH_MAX)) {
+               dprintf ("Sysfs not supported on this system\n");
+               return -1;
+       }
+       safestrcat(bus_path, "/");
+       safestrcat(bus_path, SYSFS_BUS_NAME);
+       safestrcat(bus_path, "/");
+       safestrcat(bus_path, bus);
+       safestrcat(bus_path, "/");
+       safestrcat(bus_path, SYSFS_DEVICES_NAME);
+       safestrcat(bus_path, "/");
+       safestrcat(bus_path, device);
+       /*
+        * We now are at /sys/bus/"bus_name"/devices/"device" which is a link.
+        * Now read this link to reach to the device.
+        */ 
+       if (sysfs_get_link(bus_path, path, psize)) {
+               dprintf("Error getting to device %s\n", device);
+               return -1;
+       }
+       return 0;
 }
 
 /**
- * add_device_child_to_parent: adds child device to parent
- * @parent: parent device.
- * @child: child device to add.
+ * sysfs_open_device: open a device by id (use the "bus" subsystem)
+ * @bus: bus the device belongs to
+ * @bus_id: bus_id of the device to open - has to be the "bus_id" in 
+ *             /sys/bus/xxx/devices
+ * returns struct sysfs_device if found, NULL otherwise
+ * NOTE: 
+ * 1. Use sysfs_close_device to close the device
+ * 2. Bus the device is on must be supplied
+ *     Use sysfs_find_device_bus to get the bus name
  */
-static void add_device_child_to_parent(struct sysfs_device *parent,
-                                       struct sysfs_device *child)
+struct sysfs_device *sysfs_open_device(const char *bus,        const char *bus_id)
 {
-       if (parent != NULL && child != NULL) {
-               child->next = parent->children;
-               parent->children = child;
-               child->parent = parent;
+       char sysfs_path[SYSFS_PATH_MAX];
+       struct sysfs_device *device;
+
+       if (!bus_id || !bus) {
+               errno = EINVAL;
+               return NULL;
+       }
+       memset(sysfs_path, 0, SYSFS_PATH_MAX);
+       if (get_device_absolute_path(bus_id, bus, sysfs_path, 
+                               SYSFS_PATH_MAX)) {
+               dprintf("Error getting to device %s\n", bus_id);
+               return NULL;
+       }
+       
+       device = sysfs_open_device_path(sysfs_path);
+       if (!device) {
+               dprintf("Error opening device %s\n", bus_id);
+               return NULL;
        }
+
+       return device;
 }
 
 /**
- * sysfs_open_device_tree: opens root device and all of its children,
- *     creating a tree of devices. Only opens children.
- * @path: sysfs path to devices
- * returns struct sysfs_device and its children with success or NULL with
- *     error.
+ * sysfs_get_device_parent: opens up given device's parent and returns a 
+ *     reference to its sysfs_device
+ * @dev: sysfs_device whose parent is requested
+ * Returns sysfs_device of the parent on success and NULL on failure
  */
-struct sysfs_device *sysfs_open_device_tree(const char *path)
+struct sysfs_device *sysfs_get_device_parent(struct sysfs_device *dev)
 {
-       struct sysfs_device *rootdev = NULL, *new = NULL;
-       struct sysfs_directory *cur = NULL;
+       char ppath[SYSFS_PATH_MAX], *tmp;
 
-       if (path == NULL) {
+       if (!dev) {
                errno = EINVAL;
                return NULL;
        }
-       rootdev = sysfs_open_device(path);
-       if (rootdev == NULL) {
-               dprintf(stderr, "Error opening root device at %s\n", path);
+
+       if (dev->parent)
+               return (dev->parent);
+
+       memset(ppath, 0, SYSFS_PATH_MAX);
+       safestrcpy(ppath, dev->path);
+       tmp = strrchr(ppath, '/');
+       if (!tmp) {
+               dprintf("Invalid path to device %s\n", ppath);
                return NULL;
        }
-       cur = rootdev->directory->subdirs;
-       while (cur != NULL) {
-               new = sysfs_open_device_tree(cur->path);
-               if (new == NULL) {
-                       dprintf(stderr, "Error opening device tree at %s\n",
-                               cur->path);
-                       sysfs_close_device_tree(rootdev);
+       if (*(tmp + 1) == '\0') {
+               *tmp = '\0';
+               tmp = strrchr(tmp, '/');
+               if (tmp == NULL) {
+                       dprintf("Invalid path to device %s\n", ppath);
                        return NULL;
                }
-               add_device_child_to_parent(rootdev, new);       
-               cur = cur->next;
        }
+       *tmp = '\0';
 
-       return rootdev;
+       /*
+        * All "devices" have the "detach_state" attribute - validate here
+        */
+       safestrcat(ppath, "/detach_state");
+       if (sysfs_path_is_file(ppath)) {
+               dprintf("Device at %s does not have a parent\n", dev->path);
+               return NULL;
+       }
+       tmp = strrchr(ppath, '/');
+       *tmp = '\0';
+       dev->parent = sysfs_open_device_path(ppath);
+       if (!dev->parent) {
+               dprintf("Error opening device %s's parent at %s\n", 
+                                       dev->bus_id, ppath);
+               return NULL;
+       }
+       return (dev->parent);
 }