Commit a0378fb9 authored by Al Viro's avatar Al Viro
Browse files

getcwd(2): saner logics around prepend_path() call 



The only negative value that might get returned by prepend_path() is
-ENAMETOOLONG, and that happens only on overflow.  The same goes for
prepend_unreachable().  Overflow is detectable by observing negative
buflen, so we can simplify the control flow around the prepend_path()
call.  Expand prepend_unreachable(), while we are at it - that's the
only caller.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9024348f

fs/d_path.c

+4 −13
Original line number Diff line number Diff line
@@ -211,11 +211,6 @@ char *d_absolute_path(const struct path *path, 
	return res;

}



static int prepend_unreachable(char **buffer, int *buflen)

{

	return prepend(buffer, buflen, "(unreachable)", 13);

}



static void get_fs_root_rcu(struct fs_struct *fs, struct path *root)

{

	unsigned seq;
@@ -414,16 +409,12 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) 
		int buflen = PATH_MAX;



		prepend(&cwd, &buflen, "", 1);

		error = prepend_path(&pwd, &root, &cwd, &buflen);

		if (prepend_path(&pwd, &root, &cwd, &buflen) > 0)

			prepend(&cwd, &buflen, "(unreachable)", 13);

		rcu_read_unlock();



		if (error < 0)

			goto out;



		/* Unreachable from current root */

		if (error > 0) {

			error = prepend_unreachable(&cwd, &buflen);

			if (error)

		if (buflen < 0) {

			error = -ENAMETOOLONG;

			goto out;

		}