Debug replace_fd()

From: Pavel Roskin <proski@gnu.org>


---

 fs/coredump.c |    4 +++-
 fs/file.c     |   27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletions(-)


diff --git a/fs/coredump.c b/fs/coredump.c
index fd37fac..2a5ce3c 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -440,6 +440,7 @@ static void wait_for_dump_helpers(struct file *file)
  * is a special value that we use to trap recursive
  * core dumps
  */
+int replace_fd_debug(unsigned fd, struct file *file, unsigned flags);
 static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 {
 	struct file *files[2];
@@ -450,7 +451,8 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 
 	cp->file = files[1];
 
-	replace_fd(0, files[0], 0);
+	err = replace_fd_debug(0, files[0], 0);
+	printk("%s: replace_fd_debug returned %d\n", __func__, err);
 	/* and disallow core files too */
 	current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
 
diff --git a/fs/file.c b/fs/file.c
index d3b5fa8..e209b3c 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -913,6 +913,33 @@ out_unlock:
 	return err;
 }
 
+int replace_fd_debug(unsigned fd, struct file *file, unsigned flags);
+int replace_fd_debug(unsigned fd, struct file *file, unsigned flags)
+{
+	int err;
+	struct files_struct *files = current->files;
+
+	printk("%s: rlimit(RLIMIT_NOFILE) = %ld\n", __func__, rlimit(RLIMIT_NOFILE));
+	printk("%s: file = %p\n", __func__, file);
+
+	if (!file)
+		return __close_fd(files, fd);
+
+	if (fd >= rlimit(RLIMIT_NOFILE))
+		return -EMFILE;
+
+	spin_lock(&files->file_lock);
+	err = expand_files(files, fd);
+	printk("%s: expand_files returned %d\n", __func__, err);
+	if (unlikely(err < 0))
+		goto out_unlock;
+	return do_dup2(files, file, fd, flags);
+
+out_unlock:
+	spin_unlock(&files->file_lock);
+	return err;
+}
+
 SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
 {
 	int err = -EBADF;