#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/srcu.h>
+#include <asm/poll.h>
#include "internal.h"
+struct poll_table_struct;
+
static ssize_t default_read_file(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
* debugfs_use_file_start() must be followed by a matching call
* to debugfs_use_file_finish().
*/
-static int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
+int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
__acquires(&debugfs_srcu)
{
*srcu_idx = srcu_read_lock(&debugfs_srcu);
return -EIO;
return 0;
}
+EXPORT_SYMBOL_GPL(debugfs_use_file_start);
/**
* debugfs_use_file_finish - mark the end of file data access
* debugfs_remove_recursive() blocked by a former call to
* debugfs_use_file_start() to proceed and return to its caller.
*/
-static void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu)
+void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu)
{
srcu_read_unlock(&debugfs_srcu, srcu_idx);
}
+EXPORT_SYMBOL_GPL(debugfs_use_file_finish);
#define F_DENTRY(filp) ((filp)->f_path.dentry)
.open = open_proxy_open,
};
+#define PROTO(args...) args
+#define ARGS(args...) args
+
+#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
+static ret_type full_proxy_ ## name(proto) \
+{ \
+ const struct dentry *dentry = F_DENTRY(filp); \
+ const struct file_operations *real_fops = \
+ REAL_FOPS_DEREF(dentry); \
+ int srcu_idx; \
+ ret_type r; \
+ \
+ r = debugfs_use_file_start(dentry, &srcu_idx); \
+ if (likely(!r)) \
+ r = real_fops->name(args); \
+ debugfs_use_file_finish(srcu_idx); \
+ return r; \
+}
+
+FULL_PROXY_FUNC(llseek, loff_t, filp,
+ PROTO(struct file *filp, loff_t offset, int whence),
+ ARGS(filp, offset, whence));
+
+FULL_PROXY_FUNC(read, ssize_t, filp,
+ PROTO(struct file *filp, char __user *buf, size_t size,
+ loff_t *ppos),
+ ARGS(filp, buf, size, ppos));
+
+FULL_PROXY_FUNC(write, ssize_t, filp,
+ PROTO(struct file *filp, const char __user *buf, size_t size,
+ loff_t *ppos),
+ ARGS(filp, buf, size, ppos));
+
+FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
+ PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
+ ARGS(filp, cmd, arg));
+
+static unsigned int full_proxy_poll(struct file *filp,
+ struct poll_table_struct *wait)
+{
+ const struct dentry *dentry = F_DENTRY(filp);
+ const struct file_operations *real_fops = REAL_FOPS_DEREF(dentry);
+ int srcu_idx;
+ unsigned int r = 0;
+
+ if (debugfs_use_file_start(dentry, &srcu_idx)) {
+ debugfs_use_file_finish(srcu_idx);
+ return POLLHUP;
+ }
+
+ r = real_fops->poll(filp, wait);
+ debugfs_use_file_finish(srcu_idx);
+ return r;
+}
+
+static int full_proxy_release(struct inode *inode, struct file *filp)
+{
+ const struct dentry *dentry = F_DENTRY(filp);
+ const struct file_operations *real_fops = REAL_FOPS_DEREF(dentry);
+ const struct file_operations *proxy_fops = filp->f_op;
+ int r = 0;
+
+ /*
+ * We must not protect this against removal races here: the
+ * original releaser should be called unconditionally in order
+ * not to leak any resources. Releasers must not assume that
+ * ->i_private is still being meaningful here.
+ */
+ if (real_fops->release)
+ r = real_fops->release(inode, filp);
+
+ replace_fops(filp, d_inode(dentry)->i_fop);
+ kfree((void *)proxy_fops);
+ fops_put(real_fops);
+ return 0;
+}
+
+static void __full_proxy_fops_init(struct file_operations *proxy_fops,
+ const struct file_operations *real_fops)
+{
+ proxy_fops->release = full_proxy_release;
+ if (real_fops->llseek)
+ proxy_fops->llseek = full_proxy_llseek;
+ if (real_fops->read)
+ proxy_fops->read = full_proxy_read;
+ if (real_fops->write)
+ proxy_fops->write = full_proxy_write;
+ if (real_fops->poll)
+ proxy_fops->poll = full_proxy_poll;
+ if (real_fops->unlocked_ioctl)
+ proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
+}
+
+static int full_proxy_open(struct inode *inode, struct file *filp)
+{
+ const struct dentry *dentry = F_DENTRY(filp);
+ const struct file_operations *real_fops = NULL;
+ struct file_operations *proxy_fops = NULL;
+ int srcu_idx, r;
+
+ r = debugfs_use_file_start(dentry, &srcu_idx);
+ if (r) {
+ r = -ENOENT;
+ goto out;
+ }
+
+ real_fops = REAL_FOPS_DEREF(dentry);
+ real_fops = fops_get(real_fops);
+ if (!real_fops) {
+ /* Huh? Module did not cleanup after itself at exit? */
+ WARN(1, "debugfs file owner did not clean up at exit: %pd",
+ dentry);
+ r = -ENXIO;
+ goto out;
+ }
+
+ proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
+ if (!proxy_fops) {
+ r = -ENOMEM;
+ goto free_proxy;
+ }
+ __full_proxy_fops_init(proxy_fops, real_fops);
+ replace_fops(filp, proxy_fops);
+
+ if (real_fops->open) {
+ r = real_fops->open(inode, filp);
+
+ if (filp->f_op != proxy_fops) {
+ /* No protection against file removal anymore. */
+ WARN(1, "debugfs file owner replaced proxy fops: %pd",
+ dentry);
+ goto free_proxy;
+ }
+ }
+
+ goto out;
+free_proxy:
+ kfree(proxy_fops);
+ fops_put(real_fops);
+out:
+ debugfs_use_file_finish(srcu_idx);
+ return r;
+}
+
+const struct file_operations debugfs_full_proxy_file_operations = {
+ .open = full_proxy_open,
+};
+
static struct dentry *debugfs_create_mode(const char *name, umode_t mode,
struct dentry *parent, void *value,
const struct file_operations *fops,
projects / cascardo / linux.git / blobdiff