v4.19.13 snapshot.
diff --git a/fs/readdir.c b/fs/readdir.c
new file mode 100644
index 0000000..d97f548
--- /dev/null
+++ b/fs/readdir.c
@@ -0,0 +1,498 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/fs/readdir.c
+ *
+ * Copyright (C) 1995 Linus Torvalds
+ */
+
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/time.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/stat.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/dirent.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/unistd.h>
+#include <linux/compat.h>
+
+#include <linux/uaccess.h>
+
+int iterate_dir(struct file *file, struct dir_context *ctx)
+{
+ struct inode *inode = file_inode(file);
+ bool shared = false;
+ int res = -ENOTDIR;
+ if (file->f_op->iterate_shared)
+ shared = true;
+ else if (!file->f_op->iterate)
+ goto out;
+
+ res = security_file_permission(file, MAY_READ);
+ if (res)
+ goto out;
+
+ if (shared)
+ res = down_read_killable(&inode->i_rwsem);
+ else
+ res = down_write_killable(&inode->i_rwsem);
+ if (res)
+ goto out;
+
+ res = -ENOENT;
+ if (!IS_DEADDIR(inode)) {
+ ctx->pos = file->f_pos;
+ if (shared)
+ res = file->f_op->iterate_shared(file, ctx);
+ else
+ res = file->f_op->iterate(file, ctx);
+ file->f_pos = ctx->pos;
+ fsnotify_access(file);
+ file_accessed(file);
+ }
+ if (shared)
+ inode_unlock_shared(inode);
+ else
+ inode_unlock(inode);
+out:
+ return res;
+}
+EXPORT_SYMBOL(iterate_dir);
+
+/*
+ * Traditional linux readdir() handling..
+ *
+ * "count=1" is a special case, meaning that the buffer is one
+ * dirent-structure in size and that the code can't handle more
+ * anyway. Thus the special "fillonedir()" function for that
+ * case (the low-level handlers don't need to care about this).
+ */
+
+#ifdef __ARCH_WANT_OLD_READDIR
+
+struct old_linux_dirent {
+ unsigned long d_ino;
+ unsigned long d_offset;
+ unsigned short d_namlen;
+ char d_name[1];
+};
+
+struct readdir_callback {
+ struct dir_context ctx;
+ struct old_linux_dirent __user * dirent;
+ int result;
+};
+
+static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
+{
+ struct readdir_callback *buf =
+ container_of(ctx, struct readdir_callback, ctx);
+ struct old_linux_dirent __user * dirent;
+ unsigned long d_ino;
+
+ if (buf->result)
+ return -EINVAL;
+ d_ino = ino;
+ if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
+ buf->result = -EOVERFLOW;
+ return -EOVERFLOW;
+ }
+ buf->result++;
+ dirent = buf->dirent;
+ if (!access_ok(VERIFY_WRITE, dirent,
+ (unsigned long)(dirent->d_name + namlen + 1) -
+ (unsigned long)dirent))
+ goto efault;
+ if ( __put_user(d_ino, &dirent->d_ino) ||
+ __put_user(offset, &dirent->d_offset) ||
+ __put_user(namlen, &dirent->d_namlen) ||
+ __copy_to_user(dirent->d_name, name, namlen) ||
+ __put_user(0, dirent->d_name + namlen))
+ goto efault;
+ return 0;
+efault:
+ buf->result = -EFAULT;
+ return -EFAULT;
+}
+
+SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
+ struct old_linux_dirent __user *, dirent, unsigned int, count)
+{
+ int error;
+ struct fd f = fdget_pos(fd);
+ struct readdir_callback buf = {
+ .ctx.actor = fillonedir,
+ .dirent = dirent
+ };
+
+ if (!f.file)
+ return -EBADF;
+
+ error = iterate_dir(f.file, &buf.ctx);
+ if (buf.result)
+ error = buf.result;
+
+ fdput_pos(f);
+ return error;
+}
+
+#endif /* __ARCH_WANT_OLD_READDIR */
+
+/*
+ * New, all-improved, singing, dancing, iBCS2-compliant getdents()
+ * interface.
+ */
+struct linux_dirent {
+ unsigned long d_ino;
+ unsigned long d_off;
+ unsigned short d_reclen;
+ char d_name[1];
+};
+
+struct getdents_callback {
+ struct dir_context ctx;
+ struct linux_dirent __user * current_dir;
+ struct linux_dirent __user * previous;
+ int count;
+ int error;
+};
+
+static int filldir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
+{
+ struct linux_dirent __user * dirent;
+ struct getdents_callback *buf =
+ container_of(ctx, struct getdents_callback, ctx);
+ unsigned long d_ino;
+ int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
+ sizeof(long));
+
+ buf->error = -EINVAL; /* only used if we fail.. */
+ if (reclen > buf->count)
+ return -EINVAL;
+ d_ino = ino;
+ if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
+ buf->error = -EOVERFLOW;
+ return -EOVERFLOW;
+ }
+ dirent = buf->previous;
+ if (dirent) {
+ if (signal_pending(current))
+ return -EINTR;
+ if (__put_user(offset, &dirent->d_off))
+ goto efault;
+ }
+ dirent = buf->current_dir;
+ if (__put_user(d_ino, &dirent->d_ino))
+ goto efault;
+ if (__put_user(reclen, &dirent->d_reclen))
+ goto efault;
+ if (copy_to_user(dirent->d_name, name, namlen))
+ goto efault;
+ if (__put_user(0, dirent->d_name + namlen))
+ goto efault;
+ if (__put_user(d_type, (char __user *) dirent + reclen - 1))
+ goto efault;
+ buf->previous = dirent;
+ dirent = (void __user *)dirent + reclen;
+ buf->current_dir = dirent;
+ buf->count -= reclen;
+ return 0;
+efault:
+ buf->error = -EFAULT;
+ return -EFAULT;
+}
+
+SYSCALL_DEFINE3(getdents, unsigned int, fd,
+ struct linux_dirent __user *, dirent, unsigned int, count)
+{
+ struct fd f;
+ struct linux_dirent __user * lastdirent;
+ struct getdents_callback buf = {
+ .ctx.actor = filldir,
+ .count = count,
+ .current_dir = dirent
+ };
+ int error;
+
+ if (!access_ok(VERIFY_WRITE, dirent, count))
+ return -EFAULT;
+
+ f = fdget_pos(fd);
+ if (!f.file)
+ return -EBADF;
+
+ error = iterate_dir(f.file, &buf.ctx);
+ if (error >= 0)
+ error = buf.error;
+ lastdirent = buf.previous;
+ if (lastdirent) {
+ if (put_user(buf.ctx.pos, &lastdirent->d_off))
+ error = -EFAULT;
+ else
+ error = count - buf.count;
+ }
+ fdput_pos(f);
+ return error;
+}
+
+struct getdents_callback64 {
+ struct dir_context ctx;
+ struct linux_dirent64 __user * current_dir;
+ struct linux_dirent64 __user * previous;
+ int count;
+ int error;
+};
+
+static int filldir64(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
+{
+ struct linux_dirent64 __user *dirent;
+ struct getdents_callback64 *buf =
+ container_of(ctx, struct getdents_callback64, ctx);
+ int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
+ sizeof(u64));
+
+ buf->error = -EINVAL; /* only used if we fail.. */
+ if (reclen > buf->count)
+ return -EINVAL;
+ dirent = buf->previous;
+ if (dirent) {
+ if (signal_pending(current))
+ return -EINTR;
+ if (__put_user(offset, &dirent->d_off))
+ goto efault;
+ }
+ dirent = buf->current_dir;
+ if (__put_user(ino, &dirent->d_ino))
+ goto efault;
+ if (__put_user(0, &dirent->d_off))
+ goto efault;
+ if (__put_user(reclen, &dirent->d_reclen))
+ goto efault;
+ if (__put_user(d_type, &dirent->d_type))
+ goto efault;
+ if (copy_to_user(dirent->d_name, name, namlen))
+ goto efault;
+ if (__put_user(0, dirent->d_name + namlen))
+ goto efault;
+ buf->previous = dirent;
+ dirent = (void __user *)dirent + reclen;
+ buf->current_dir = dirent;
+ buf->count -= reclen;
+ return 0;
+efault:
+ buf->error = -EFAULT;
+ return -EFAULT;
+}
+
+int ksys_getdents64(unsigned int fd, struct linux_dirent64 __user *dirent,
+ unsigned int count)
+{
+ struct fd f;
+ struct linux_dirent64 __user * lastdirent;
+ struct getdents_callback64 buf = {
+ .ctx.actor = filldir64,
+ .count = count,
+ .current_dir = dirent
+ };
+ int error;
+
+ if (!access_ok(VERIFY_WRITE, dirent, count))
+ return -EFAULT;
+
+ f = fdget_pos(fd);
+ if (!f.file)
+ return -EBADF;
+
+ error = iterate_dir(f.file, &buf.ctx);
+ if (error >= 0)
+ error = buf.error;
+ lastdirent = buf.previous;
+ if (lastdirent) {
+ typeof(lastdirent->d_off) d_off = buf.ctx.pos;
+ if (__put_user(d_off, &lastdirent->d_off))
+ error = -EFAULT;
+ else
+ error = count - buf.count;
+ }
+ fdput_pos(f);
+ return error;
+}
+
+
+SYSCALL_DEFINE3(getdents64, unsigned int, fd,
+ struct linux_dirent64 __user *, dirent, unsigned int, count)
+{
+ return ksys_getdents64(fd, dirent, count);
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_old_linux_dirent {
+ compat_ulong_t d_ino;
+ compat_ulong_t d_offset;
+ unsigned short d_namlen;
+ char d_name[1];
+};
+
+struct compat_readdir_callback {
+ struct dir_context ctx;
+ struct compat_old_linux_dirent __user *dirent;
+ int result;
+};
+
+static int compat_fillonedir(struct dir_context *ctx, const char *name,
+ int namlen, loff_t offset, u64 ino,
+ unsigned int d_type)
+{
+ struct compat_readdir_callback *buf =
+ container_of(ctx, struct compat_readdir_callback, ctx);
+ struct compat_old_linux_dirent __user *dirent;
+ compat_ulong_t d_ino;
+
+ if (buf->result)
+ return -EINVAL;
+ d_ino = ino;
+ if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
+ buf->result = -EOVERFLOW;
+ return -EOVERFLOW;
+ }
+ buf->result++;
+ dirent = buf->dirent;
+ if (!access_ok(VERIFY_WRITE, dirent,
+ (unsigned long)(dirent->d_name + namlen + 1) -
+ (unsigned long)dirent))
+ goto efault;
+ if ( __put_user(d_ino, &dirent->d_ino) ||
+ __put_user(offset, &dirent->d_offset) ||
+ __put_user(namlen, &dirent->d_namlen) ||
+ __copy_to_user(dirent->d_name, name, namlen) ||
+ __put_user(0, dirent->d_name + namlen))
+ goto efault;
+ return 0;
+efault:
+ buf->result = -EFAULT;
+ return -EFAULT;
+}
+
+COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
+ struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
+{
+ int error;
+ struct fd f = fdget_pos(fd);
+ struct compat_readdir_callback buf = {
+ .ctx.actor = compat_fillonedir,
+ .dirent = dirent
+ };
+
+ if (!f.file)
+ return -EBADF;
+
+ error = iterate_dir(f.file, &buf.ctx);
+ if (buf.result)
+ error = buf.result;
+
+ fdput_pos(f);
+ return error;
+}
+
+struct compat_linux_dirent {
+ compat_ulong_t d_ino;
+ compat_ulong_t d_off;
+ unsigned short d_reclen;
+ char d_name[1];
+};
+
+struct compat_getdents_callback {
+ struct dir_context ctx;
+ struct compat_linux_dirent __user *current_dir;
+ struct compat_linux_dirent __user *previous;
+ int count;
+ int error;
+};
+
+static int compat_filldir(struct dir_context *ctx, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
+{
+ struct compat_linux_dirent __user * dirent;
+ struct compat_getdents_callback *buf =
+ container_of(ctx, struct compat_getdents_callback, ctx);
+ compat_ulong_t d_ino;
+ int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
+ namlen + 2, sizeof(compat_long_t));
+
+ buf->error = -EINVAL; /* only used if we fail.. */
+ if (reclen > buf->count)
+ return -EINVAL;
+ d_ino = ino;
+ if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
+ buf->error = -EOVERFLOW;
+ return -EOVERFLOW;
+ }
+ dirent = buf->previous;
+ if (dirent) {
+ if (signal_pending(current))
+ return -EINTR;
+ if (__put_user(offset, &dirent->d_off))
+ goto efault;
+ }
+ dirent = buf->current_dir;
+ if (__put_user(d_ino, &dirent->d_ino))
+ goto efault;
+ if (__put_user(reclen, &dirent->d_reclen))
+ goto efault;
+ if (copy_to_user(dirent->d_name, name, namlen))
+ goto efault;
+ if (__put_user(0, dirent->d_name + namlen))
+ goto efault;
+ if (__put_user(d_type, (char __user *) dirent + reclen - 1))
+ goto efault;
+ buf->previous = dirent;
+ dirent = (void __user *)dirent + reclen;
+ buf->current_dir = dirent;
+ buf->count -= reclen;
+ return 0;
+efault:
+ buf->error = -EFAULT;
+ return -EFAULT;
+}
+
+COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
+ struct compat_linux_dirent __user *, dirent, unsigned int, count)
+{
+ struct fd f;
+ struct compat_linux_dirent __user * lastdirent;
+ struct compat_getdents_callback buf = {
+ .ctx.actor = compat_filldir,
+ .current_dir = dirent,
+ .count = count
+ };
+ int error;
+
+ if (!access_ok(VERIFY_WRITE, dirent, count))
+ return -EFAULT;
+
+ f = fdget_pos(fd);
+ if (!f.file)
+ return -EBADF;
+
+ error = iterate_dir(f.file, &buf.ctx);
+ if (error >= 0)
+ error = buf.error;
+ lastdirent = buf.previous;
+ if (lastdirent) {
+ if (put_user(buf.ctx.pos, &lastdirent->d_off))
+ error = -EFAULT;
+ else
+ error = count - buf.count;
+ }
+ fdput_pos(f);
+ return error;
+}
+#endif