1 files changed, 118 insertions, 0 deletions
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
new file mode 100644
index 000000000..c45306a9f
--- /dev/null
+++ b/include/linux/fdtable.h
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * descriptor table internals; you almost certainly want file.h instead.
+ */
+
+#ifndef __LINUX_FDTABLE_H
+#define __LINUX_FDTABLE_H
+
+#include <linux/posix_types.h>
+#include <linux/compiler.h>
+#include <linux/spinlock.h>
+#include <linux/rcupdate.h>
+#include <linux/nospec.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+
+#include <linux/atomic.h>
+
+/*
+ * The default fd array needs to be at least BITS_PER_LONG,
+ * as this is the granularity returned by copy_fdset().
+ */
+#define NR_OPEN_DEFAULT BITS_PER_LONG
+
+struct fdtable {
+	unsigned int max_fds;
+	struct file __rcu **fd;      /* current fd array */
+	unsigned long *close_on_exec;
+	unsigned long *open_fds;
+	unsigned long *full_fds_bits;
+	struct rcu_head rcu;
+};
+
+/*
+ * Open file table structure
+ */
+struct files_struct {
+  /*
+   * read mostly part
+   */
+	atomic_t count;
+	bool resize_in_progress;
+	wait_queue_head_t resize_wait;
+
+	struct fdtable __rcu *fdt;
+	struct fdtable fdtab;
+  /*
+   * written part on a separate cache line in SMP
+   */
+	spinlock_t file_lock ____cacheline_aligned_in_smp;
+	unsigned int next_fd;
+	unsigned long close_on_exec_init[1];
+	unsigned long open_fds_init[1];
+	unsigned long full_fds_bits_init[1];
+	struct file __rcu * fd_array[NR_OPEN_DEFAULT];
+};
+
+struct file_operations;
+struct vfsmount;
+struct dentry;
+
+#define rcu_dereference_check_fdtable(files, fdtfd) \
+	rcu_dereference_check((fdtfd), lockdep_is_held(&(files)->file_lock))
+
+#define files_fdtable(files) \
+	rcu_dereference_check_fdtable((files), (files)->fdt)
+
+/*
+ * The caller must ensure that fd table isn't shared or hold rcu or file lock
+ */
+static inline struct file *files_lookup_fd_raw(struct files_struct *files, unsigned int fd)
+{
+	struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+	unsigned long mask = array_index_mask_nospec(fd, fdt->max_fds);
+	struct file *needs_masking;
+
+	/*
+	 * 'mask' is zero for an out-of-bounds fd, all ones for ok.
+	 * 'fd&mask' is 'fd' for ok, or 0 for out of bounds.
+	 *
+	 * Accessing fdt->fd[0] is ok, but needs masking of the result.
+	 */
+	needs_masking = rcu_dereference_raw(fdt->fd[fd&mask]);
+	return (struct file *)(mask & (unsigned long)needs_masking);
+}
+
+static inline struct file *files_lookup_fd_locked(struct files_struct *files, unsigned int fd)
+{
+	RCU_LOCKDEP_WARN(!lockdep_is_held(&files->file_lock),
+			   "suspicious rcu_dereference_check() usage");
+	return files_lookup_fd_raw(files, fd);
+}
+
+static inline bool close_on_exec(unsigned int fd, const struct files_struct *files)
+{
+	return test_bit(fd, files_fdtable(files)->close_on_exec);
+}
+
+struct task_struct;
+
+void put_files_struct(struct files_struct *fs);
+int unshare_files(void);
+struct fd_range {
+	unsigned int from, to;
+};
+struct files_struct *dup_fd(struct files_struct *, struct fd_range *) __latent_entropy;
+void do_close_on_exec(struct files_struct *);
+int iterate_fd(struct files_struct *, unsigned,
+		int (*)(const void *, struct file *, unsigned),
+		const void *);
+
+extern int close_fd(unsigned int fd);
+extern struct file *file_close_fd(unsigned int fd);
+
+extern struct kmem_cache *files_cachep;
+
+#endif /* __LINUX_FDTABLE_H */