[Toybox] [PATCH] Use LOOP_CLR_FD instead of a constant.

[Rob Landley]

On 03/28/2015 08:20 PM, enh wrote:
> Use LOOP_CLR_FD instead of a constant.
> 
> losetup.c already uses LOOP_CLR_FD.
> 
> diff --git a/toys/lsb/umount.c b/toys/lsb/umount.c
> index c7998e4..d688ad2 100644
> --- a/toys/lsb/umount.c
> +++ b/toys/lsb/umount.c
> @@ -30,6 +30,7 @@ config UMOUNT
> 
>  #define FOR_umount
>  #include "toys.h"
> +#include <linux/loop.h>
> 
>  GLOBALS(
>    struct arg_list *t;
> @@ -84,8 +85,7 @@ static void do_umount(char *dir, char *dev, int flags)
>        int lfd = open(dev, O_RDONLY);
> 
>        if (lfd != -1) {
> -        // This is LOOP_CLR_FD, fetching it from headers is awkward
> -        if (!ioctl(lfd, 0x4C01) && (toys.optflags & FLAG_v))
> +        if (!ioctl(lfd, LOOP_CLR_FD) && (toys.optflags & FLAG_v))

The "awkward" part is that #including a linux/*.h header from a command
that's been in every unix for over 40 years (whatever posix has to say
on the matter) seems a bit impolite to bsd and mac.

I can put some sort of if (LINUX) around the ioctl call if that random
ioctl turns out to be harmful on those systems (rather than just a
random -ENOCLUE or similar), but conditionally chopping out a header
that way is the kind of ugliness I try to hide in portability.h.

Not a _strong_ reason, but that's why I did it.

Rob

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