From a0378fb9b33308fb4547f098c6281af8ab4b5fb5 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 17 May 2021 21:56:38 -0400 Subject: 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: Al Viro --- fs/d_path.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) (limited to 'fs/d_path.c') diff --git a/fs/d_path.c b/fs/d_path.c index 7f3fac544bbb..311d43287572 100644 --- a/fs/d_path.c +++ b/fs/d_path.c @@ -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; @@ -414,17 +409,13 @@ 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) + if (buflen < 0) { + error = -ENAMETOOLONG; goto out; - - /* Unreachable from current root */ - if (error > 0) { - error = prepend_unreachable(&cwd, &buflen); - if (error) - goto out; } error = -ERANGE; -- cgit