fix musl problem with dirname, now for all users of bb_make_directory()

function                                             old     new   delta
bb_make_directory                                    412     419      +7
install_main                                         793     769     -24
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 7/-24)             Total: -17 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 16 insertions, 11 deletions

diff --git a/coreutils/install.c b/coreutils/install.c
index d0dcd0e89..831f9b802 100644
--- a/coreutils/install.c
+++ b/coreutils/install.c
@@ -209,16 +209,10 @@ int install_main(int argc, char **argv)
                         dest = last;
                         if (opts & OPT_MKDIR_LEADING) {
                                 char *ddir = xstrdup(dest);
-                                char *dn = dirname(ddir);
-                                /* musl can return read-only "/" or "." string.
-                                 * bb_make_directory needs writable string.
+                                bb_make_directory(dirname(ddir), 0755, mkdir_flags);
+                                /* errors are not checked. copy_file
+                                 * will fail if dir is not created.
                                  */
-                                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)
diff --git a/libbb/make_directory.c b/libbb/make_directory.c
index 89352ca1f..a6b7c28df 100644
--- a/libbb/make_directory.c
+++ b/libbb/make_directory.c
@@ -35,9 +35,20 @@ int FAST_FUNC bb_make_directory(char *path, long mode, int flags)
         char c;
         struct stat st;
 
-        /* Happens on bb_make_directory(dirname("no_slashes"),...) */
-        if (LONE_CHAR(path, '.'))
+        /* "path" can be a result of dirname().
+         * dirname("no_slashes") returns ".", possibly read-only.
+         * musl dirname() can return read-only "/" too.
+         * We need writable string. And for "/", "." (and ".."?)
+         * nothing needs to be created anyway.
+         */
+        if (LONE_CHAR(path, '/'))
                 return 0;
+        if (path[0] == '.') {
+                if (path[1] == '\0')
+                        return 0; /* "." */
+//              if (path[1] == '.' && path[2] == '\0')
+//                      return 0; /* ".." */
+        }
 
         org_mask = cur_mask = (mode_t)-1L;
         s = path;