On Thu, Dec 13, 2018 at 10:46:33AM +0000, Adrian Reber wrote:
> From: Adrian Reber <areber at redhat.com>
>
> While writing runc test cases to verify that runc correctly uses RPC
> configuration files it became clear that some things were not working as
> they are supposed to. Looking closer at the code to set log files
> via RPC configuration files I discovered that the code seems wrong (at
> least I did not understand it any more (or the intentions behind it)).
>
> This code tries to simplify that logic a bit and add more comments to
> make clear what the intentions of the RPC configuration file code is.
>
> Signed-off-by: Adrian Reber <areber at redhat.com>
> ---
> criu/cr-service.c | 37 +++++++++++++++++++++++++++++++------
> 1 file changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/criu/cr-service.c b/criu/cr-service.c
> index 4a9983a..61139d4 100644
> --- a/criu/cr-service.c
> +++ b/criu/cr-service.c
> @@ -292,23 +292,38 @@ static int setup_opts_from_req(int sk, CriuOpts *req)
> xfree(tmp_imgs);
> goto err;
> }
> - if (tmp_output && opts.output && !strncmp(tmp_output, opts.output, PATH_MAX))
> + /* If this is non-NULL, the RPC configuration file had a value, use it.*/
> + if (opts.output)
> output_changed_by_rpc_conf = true;
> - if (tmp_work && opts.work_dir && !strncmp(tmp_work, opts.work_dir, PATH_MAX))
> + /* If this is NULL, use the old value if it was set. */
> + if (!opts.output && tmp_output)
> + opts.output = xstrdup(tmp_output);
tmp_output is a copy of opts.output:
tmp_output = xstrdup(opts.output);
Why do we need xstrdup() here? Maybe something like this:
opts.output = tmp_output;
tmp_output = NULL;
BTW: xstrdup can fail, so we have to check its return value.
> +
> + if (opts.work_dir)
> work_changed_by_rpc_conf = true;
> - if (tmp_imgs && opts.imgs_dir && !strncmp(tmp_imgs, opts.imgs_dir, PATH_MAX))
> + if (!opts.work_dir && tmp_work)
> + opts.work_dir = xstrdup(tmp_work);
> +
> + if (opts.imgs_dir)
> imgs_changed_by_rpc_conf = true;
> + /*
> + * As the images directory is a required RPC setting, it is not
> + * necessary to use the value from other configuration files.
> + * Either it is set in the RPC configuration file or it is set
> + * via RPC.
> + */
> xfree(tmp_output);
> xfree(tmp_work);
> xfree(tmp_imgs);
> }
>
> /*
> - * open images_dir
> + * open images_dir - images_dir_fd is a required RPC parameter
> + *
> * This assumes that if opts.imgs_dir is set we have a value
> * from the configuration file parser. The test to see that
> * imgs_changed_by_rpc_conf is true is used to make sure the value
> - * is not the same as from one of the other configuration files.
> + * is from the RPC configuration file.
> * The idea is that only the RPC configuration file is able to
> * overwrite RPC settings:
> * * apply_config(global_conf)
> @@ -338,10 +353,16 @@ static int setup_opts_from_req(int sk, CriuOpts *req)
>
> /* chdir to work dir */
> if (opts.work_dir && work_changed_by_rpc_conf)
> + /* Use the value from the RPC configuration file first. */
> strncpy(work_dir_path, opts.work_dir, PATH_MAX - 1);
> else if (req->has_work_dir_fd)
> + /* Use the value set via RPC. */
> sprintf(work_dir_path, "/proc/%d/fd/%d", ids.pid, req->work_dir_fd);
> + else if (opts.work_dir)
> + /* Use the value from one of the other configuration files. */
> + strncpy(work_dir_path, opts.work_dir, PATH_MAX - 1);
> else
> + /* Use the images directory a work directory. */
> strcpy(work_dir_path, images_dir_path);
>
> if (chdir(work_dir_path)) {
> @@ -350,7 +371,11 @@ static int setup_opts_from_req(int sk, CriuOpts *req)
> }
>
> /* initiate log file in work dir */
> - if (req->log_file && !(opts.output && output_changed_by_rpc_conf)) {
> + if (req->log_file && !(opts.output && output_changed_by_rpc_conf)) {
output_changed_by_rpc_conf is true only if opts.output isn't NULL
> + /*
> + * If RPC sets a log file and if there nothing from the
> + * RPC configuration file, use the RPC value.
> + */
> if (strchr(req->log_file, '/')) {
> pr_perror("No subdirs are allowed in log_file name");
> goto err;
> --
> 1.8.3.1
>