file: write through symlinks on uci commit

The rename() syscall operates on the destination path directly, therfore
resolve the real path before doing the rename to not clobber the destination
in case it is a symlink pointing to another file.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

diff --git a/file.c b/file.c
index 35755d83ad8c04dc016d1045e9c3ae4f44b0354c..7e1e4e6f0ddcdbb545c4e83efda52fb33031374a 100644 (file)
--- a/file.c
+++ b/file.c
@@ -800,9 +800,13 @@ done:
        free(name);
        free(path);
        uci_close_stream(f1);
-       if (do_rename && rename(filename, p->path)) {
-               unlink(filename);
-               UCI_THROW(ctx, UCI_ERR_IO);
+       if (do_rename) {
+               path = realpath(p->path, NULL);
+               if (!path || rename(filename, path)) {
+                       unlink(filename);
+                       UCI_THROW(ctx, UCI_ERR_IO);
+               }
+               free(path);
        }
        free(filename);
        if (ctx->err)