From 05b384f8aaebbc1b98bba8b7cc96c9190fc08f78 Mon Sep 17 00:00:00 2001 From: Stephan Gerhold Date: Fri, 8 Jul 2022 14:50:54 +0200 Subject: [PATCH] ucm: fix st_mode check for symbolic links The file type in the st_mode field is not encoded as unique bits but as an enumerator. Checking if some bits of S_IFLNK are set does not work correctly because it happens to evaluate to true for regular files as well. The POSIX man page suggests using the following approach to check the file type: if ((sb.st_mode & S_IFMT) == S_IFLNK) Alternatively, there is a S_ISLNK() macro to check this more easily. Make use of the latter so that readlink() is only called on actual symbolic links and not regular files. This makes audio work again with slightly older alsa-ucm-conf versions or alternative top-level ucm.conf configurations that do not make use of symlinks. Fixes: d6adde0e ("ucm: top-level path - set directory from symlink") Signed-off-by: Stephan Gerhold --- src/ucm/parser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/ucm/parser.c b/src/ucm/parser.c index 351b7c40..976aa8be 100644 --- a/src/ucm/parser.c +++ b/src/ucm/parser.c @@ -2630,7 +2630,7 @@ static int parse_toplevel_path(snd_use_case_mgr_t *uc_mgr, ucm_filename(fn, sizeof(fn), version, dir, file); if (access(fn, R_OK) == 0 && lstat64(fn, &st) == 0) { - if (st.st_mode & S_IFLNK) { + if (S_ISLNK(st.st_mode)) { ssize_t r; char *link, *dir2, *p;