devfs: Add symlink support
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
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3cff8948ff
commit
8a35fddf57
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@ -21,7 +21,7 @@
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static int do_devinfo_subtree(struct device_d *dev, int depth)
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{
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struct device_d *child;
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struct cdev *cdev;
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struct cdev *cdev, *cdevl;
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int i;
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for (i = 0; i < depth; i++)
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@ -33,11 +33,14 @@ static int do_devinfo_subtree(struct device_d *dev, int depth)
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list_for_each_entry(cdev, &dev->cdevs, devices_list) {
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for (i = 0; i < depth + 1; i++)
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printf(" ");
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printf("`-- 0x%08llx-0x%08llx (%10s): /dev/%s\n",
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printf("`-- 0x%08llx-0x%08llx (%10s): /dev/%s",
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cdev->offset,
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cdev->offset + cdev->size - 1,
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size_human_readable(cdev->size),
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cdev->name);
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list_for_each_entry(cdevl, &cdev->links, link_entry)
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printf(", %s", cdevl->name);
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printf("\n");
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}
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} else {
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printf("\n");
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@ -46,7 +46,18 @@ int devfs_partition_complete(struct string_list *sl, char *instr)
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}
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#endif
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struct cdev *cdev_by_name(const char *filename)
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struct cdev *cdev_readlink(struct cdev *cdev)
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{
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if (cdev->link)
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cdev = cdev->link;
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/* links to links are not allowed */
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BUG_ON(cdev->link);
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return cdev;
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}
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struct cdev *lcdev_by_name(const char *filename)
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{
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struct cdev *cdev;
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@ -57,6 +68,17 @@ struct cdev *cdev_by_name(const char *filename)
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return NULL;
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}
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struct cdev *cdev_by_name(const char *filename)
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{
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struct cdev *cdev;
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cdev = lcdev_by_name(filename);
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if (!cdev)
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return NULL;
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return cdev_readlink(cdev);
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}
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struct cdev *cdev_by_device_node(struct device_node *node)
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{
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struct cdev *cdev;
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@ -65,7 +87,7 @@ struct cdev *cdev_by_device_node(struct device_node *node)
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if (!cdev->device_node)
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continue;
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if (cdev->device_node == node)
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return cdev;
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return cdev_readlink(cdev);
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}
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return NULL;
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}
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@ -111,14 +133,6 @@ int cdev_find_free_index(const char *basename)
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return -EBUSY; /* all indexes are used */
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}
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int cdev_do_open(struct cdev *cdev, unsigned long flags)
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{
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if (cdev->ops->open)
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return cdev->ops->open(cdev, flags);
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return 0;
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}
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struct cdev *cdev_open(const char *name, unsigned long flags)
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{
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struct cdev *cdev;
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@ -131,9 +145,11 @@ struct cdev *cdev_open(const char *name, unsigned long flags)
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if (!cdev)
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return NULL;
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ret = cdev_do_open(cdev, flags);
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if (cdev->ops->open) {
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ret = cdev->ops->open(cdev, flags);
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if (ret)
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return NULL;
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}
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return cdev;
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}
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@ -259,6 +275,8 @@ int devfs_create(struct cdev *new)
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if (cdev)
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return -EEXIST;
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INIT_LIST_HEAD(&new->links);
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list_add_tail(&new->list, &cdev_list);
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if (new->dev) {
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list_add_tail(&new->devices_list, &new->dev->cdevs);
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@ -269,15 +287,47 @@ int devfs_create(struct cdev *new)
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return 0;
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}
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int devfs_create_link(struct cdev *cdev, const char *name)
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{
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struct cdev *new;
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if (cdev_by_name(name))
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return -EEXIST;
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/*
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* Create a link to the real cdev instead of creating
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* a link to a link.
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*/
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cdev = cdev_readlink(cdev);
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new = xzalloc(sizeof(*new));
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new->name = xstrdup(name);
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new->link = cdev;
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INIT_LIST_HEAD(&new->links);
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list_add_tail(&new->list, &cdev_list);
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list_add_tail(&new->link_entry, &cdev->links);
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return 0;
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}
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int devfs_remove(struct cdev *cdev)
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{
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struct cdev *c, *tmp;
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if (cdev->open)
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return -EBUSY;
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list_del(&cdev->list);
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if (cdev->dev)
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list_del(&cdev->devices_list);
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list_for_each_entry_safe(c, tmp, &cdev->links, link_entry)
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devfs_remove(c);
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if (cdev->link)
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free(cdev);
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return 0;
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}
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27
fs/devfs.c
27
fs/devfs.c
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@ -212,12 +212,18 @@ static int devfs_stat(struct device_d *_dev, const char *filename, struct stat *
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{
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struct cdev *cdev;
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cdev = cdev_by_name(filename + 1);
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cdev = lcdev_by_name(filename + 1);
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if (!cdev)
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return -ENOENT;
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s->st_mode = S_IFCHR;
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s->st_size = cdev->size;
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if (cdev->link)
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s->st_mode |= S_IFLNK;
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cdev = cdev_readlink(cdev);
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if (cdev->ops->write)
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s->st_mode |= S_IWUSR;
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if (cdev->ops->read)
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@ -242,6 +248,24 @@ static void devfs_delete(struct device_d *dev)
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{
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}
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static int devfs_readlink(struct device_d *dev, const char *pathname,
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char *buf, size_t bufsz)
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{
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struct cdev *cdev;
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cdev = cdev_by_name(pathname + 1);
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if (!cdev)
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return -ENOENT;
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while (cdev->link)
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cdev = cdev->link;
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bufsz = min(bufsz, strlen(cdev->name));
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memcpy(buf, cdev->name, bufsz);
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return 0;
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}
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static struct fs_driver_d devfs_driver = {
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.read = devfs_read,
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.write = devfs_write,
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@ -258,6 +282,7 @@ static struct fs_driver_d devfs_driver = {
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.erase = devfs_erase,
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.protect = devfs_protect,
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.memmap = devfs_memmap,
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.readlink = devfs_readlink,
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.flags = FS_DRIVER_NO_DEV,
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.drv = {
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.probe = devfs_probe,
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@ -450,13 +450,18 @@ struct cdev {
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int open;
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struct mtd_info *mtd;
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u8 dos_partition_type;
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struct cdev *link;
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struct list_head link_entry, links;
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};
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int devfs_create(struct cdev *);
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int devfs_create_link(struct cdev *, const char *name);
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int devfs_remove(struct cdev *);
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int cdev_find_free_index(const char *);
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struct cdev *device_find_partition(struct device_d *dev, const char *name);
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struct cdev *cdev_by_name(const char *filename);
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struct cdev *lcdev_by_name(const char *filename);
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struct cdev *cdev_readlink(struct cdev *cdev);
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struct cdev *cdev_by_device_node(struct device_node *node);
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struct cdev *cdev_open(const char *name, unsigned long flags);
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int cdev_do_open(struct cdev *, unsigned long flags);
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