On Tue, 21 Jan 2025 23:16:03 +0800
Coly Li <colyli@xxxxxxx> wrote:
> During the boot process if mdadm is called in udev context, sbin paths
> like /sbin, /usr/sbin, /usr/local/sbin normally not defined in PATH
> env variable, calling system("modprobe md_mod") in
> create_named_array() may fail with 'sh: modprobe: command not found'
> error message.
>
> We don't want to move modprobe binary into udev private directory, so
> setting the PATH env is a more proper method to avoid the above issue.
>
> This patch sets PATH env variable with
> "/sbin:/usr/sbin:/usr/local/sbin" before calling system("modprobe
> md_mod"). The change only takes effect within the udev worker
> context, not seen by global udev environment.
Hi Coly,
Nice explanation, thanks!
>
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> ---
> mdopen.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/mdopen.c b/mdopen.c
> index 26f0c716..30cf781b 100644
> --- a/mdopen.c
> +++ b/mdopen.c
> @@ -39,6 +39,18 @@ int create_named_array(char *devnm)
>
> fd = open(new_array_file, O_WRONLY);
> if (fd < 0 && errno == ENOENT) {
> + char buf[PATH_MAX];
> +
> + /*
> + * When called by udev worker context, path of
> modprobe
> + * might not be in env PATH. Set sbin paths into PATH
> + * env to avoid potential failure when run modprobe
> here.
> + */
> + memset(buf, 0, PATH_MAX);
just:
char buf[PATH_MAX] = {0};
> + snprintf(buf, PATH_MAX - 1, "%s:%s", getenv("PATH"),
> + "/sbin:/usr/sbin:/usr/local/sbin");
> + setenv("PATH", buf, 1);
Isn't it over-complicated? Why not simply:
system("/sbin/modprobe md_mod");
If modprobe is not always in /sbin (checked on my opensuse only)
we can make in configured during compilation, simple call `which
modprobe` should do the job.
What do you think?
Thanks,
Mariusz
