On Sat, 8 Oct 2016, Sergey Kubushyn wrote:
On Sat, 8 Oct 2016, Tom Rini wrote:
On Wed, Oct 05, 2016 at 12:38:01PM -0700, Sergey Kubushyn wrote:
> This adds "file exists" commands to generic FS as well as to FAT, EXT4,
> and UBIFS. Also adds "file size" command to UBIFS.
>
> The return value for "file exists" commands is REVERSED i.e. they
> return 1 if file exists and 0 otherwise. This is a deliberate decision
> because those commands are supposed to be used almost exclusively in
> scripts and TRUE value is _not_ zero while FALSE is zero.
>
> As of now the only way to check for a file existence is to attempt a
> read on that file (aka load.) That works but it makes an unnecessary
> read, overwrites memory at destination address if file not a zero
> length one, and outputs unnecessary messages to the console in any
> case.
>
> Checking file existence in scripts is a valuable feature that allows
> the higher level software (e.g. Linux) to interact with U-Boot by
> creating some semaphore files and rebooting. We do use it quite
> extensively for system setup at manufacturing time and for other
> purposes (e.g. our Android "recovery" is implemented this way.)
>
> Signed-off-by: Sergey Kubushyn <k...@koi8.net>
Can you please do this in at least two patches? file size to ubi should
be its own patch. Also:
Sure, will do later today.
> +int do_ext4_file_exists(cmd_tbl_t *cmdtp, int flag, int argc,
> + char *const argv[])
> +{
> + int ret;
> +
> + ret = do_file_exists(cmdtp, flag, argc, argv, FS_TYPE_EXT);
> + + if (ret == 0) return 1;
> + if (ret == 1) return 0;
> + return ret;
> +}
I can only assume this hasn't been compile tested in a while, and you
should simplify the code into a single if/else and a comment on what we
want/mean. Thanks!
The problem is do_file_exists() can return not just 0 if file exists or
1 if it doesn't but also a negative value for "I don't know" i.e. when
e.g. FS mount failed.
I don't know if those return codes are somehow processed further up (too
much time to dig everything to the bare metal) so I decided to return
that value as-is if it happened. Sure it could be done like e.g.
return (ret == 0);
even without any if-elses and it is probably the proper way to do it but
I fell victim of perfectionism :))
Will re-do it with the above construction and split in 2 parts. Will also
send it with git send-email so it won't end up garbled.
OK, please disregard this patch altogether. I somehow missed "test -e"
command that has been implemented something like 2 years ago and that
command makes this entire patch unnecessary.
I will rewrite my scripts with "test -e" before submitting new boards.
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