[git commit] install: fix musl problem with dirname

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=cf2600c3661c11491a838ef29733583afb6ad968
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 coreutils/install.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/coreutils/install.c b/coreutils/install.c
index e685892..d0dcd0e 100644
--- a/coreutils/install.c
+++ b/coreutils/install.c
@@ -209,9 +209,16 @@ int install_main(int argc, char **argv)
 			dest = last;
 			if (opts & OPT_MKDIR_LEADING) {
 				char *ddir = xstrdup(dest);
-				bb_make_directory(dirname(ddir), 0755, mkdir_flags);
-				/* errors are not checked. copy_file
-				 * will fail if dir is not created. */
+				char *dn = dirname(ddir);
+				/* musl can return read-only "/" or "." string.
+				 * bb_make_directory needs writable string.
+				 */
+				if ((dn[0] != '/' && dn[0] != '.') || dn[1] != '\0') {
+					bb_make_directory(dn, 0755, mkdir_flags);
+					/* errors are not checked. copy_file
+					 * will fail if dir is not created.
+					 */
+				}
 				free(ddir);
 			}
 			if (isdir)