Hi
Can you make a patch against -current? Your source tree seems pretty out
of date.
Yes please check the return values from fcntl and fstat.
On Thu, May 28, 2015 at 08:37:02PM +0200, S??bastien Marie wrote:
> Hi,
>
> It was possible, using the previous file(1) version, to determine the
> file type of stdin stream. The current version don't permit that (or I
> don't found how to do that).
>
> I would propose a patch in order to support '-' argument to be trait as
> STDIN_FILENO descriptor.
>
>
> file(1) in 5.5:
> ---------------
>
> $ echo foobar | file -
> /dev/stdin: ASCII text
>
> $ echo foobar | file -s /dev/stdin
> /dev/stdin: ASCII text
>
>
>
> file(1) in -current:
> --------------------
>
> $ echo foobar | file -
> -: cannot stat '-' (No such file or directory)
>
> $ echo foobar | file -s /dev/stdin
> /dev/stdin: data
>
>
>
> after patching:
> ---------------
>
> $ echo foobar | file -
>
> -: fifo (named pipe)
>
> $ echo foobar | file -s -
> -: ASCII text
>
> $ file - < file.c
> -: ASCII C program text
>
> $ file ./- # process the file named '-'
> ./-: cannot stat './-' (No such file or directory)
>
> $ echo foobar | file -s /dev/stdin # behaviour not changed
> /dev/stdin: data
>
>
>
> About the patch:
> - my english wording is somehow hesitant: it isn't my native language,
> but you should already have noted that :). So corrections in manpage
> are expected.
>
> - I am not sure about mdoc tags that I used (.Em for "stdin" for
> example).
>
> - I am not sure if catching fcntl(3) or fstat(3) errors would make sens
> or not.
>
> - Same for configure STDIN_FILENO for O_NONBLOCK.
>
>
> Remaining interrogations:
> - should '-' implies '-s' (as before) ?
> - should I rename "-" to "/dev/stdin" in order to have similar output
> than before ?
> - why "file -s /dev/stdin" returns "data" instead of proper
> determination ?
> - should I trait "/dev/stdin" as STDIN_FILENO too ?
>
>
> Thanks.
> --
> S??bastien Marie
>
> Index: file.1
> ===================================================================
> RCS file: /cvs/src/usr.bin/file/file.1,v
> retrieving revision 1.39
> diff -u -p -r1.39 file.1
> --- file.1 24 Apr 2015 20:57:51 -0000 1.39
> +++ file.1 28 May 2015 18:07:15 -0000
> @@ -74,6 +74,16 @@ or
> .Em data
> meaning anything else.
> .Pp
> +If the argument is
> +.Dq -
> +, it is traited as
> +.Em stdin
> +stream. When
> +.Em stdin
> +is a pipe, consider use of
> +.Fl s
> +option in order to determine the type of the stream's content.
> +.Pp
> The options are as follows:
> .Bl -tag -width indent
> .It Fl b
> Index: file.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/file/file.c,v
> retrieving revision 1.32
> diff -u -p -r1.32 file.c
> --- file.c 24 Apr 2015 17:34:57 -0000 1.32
> +++ file.c 28 May 2015 18:07:15 -0000
> @@ -197,6 +197,13 @@ static void
> open_file(struct input_file *inf)
> {
> int retval;
> +
> + if (strcmp(inf->path, "-") == 0) {
> + inf->fd = STDIN_FILENO;
> + fcntl(STDIN_FILENO, O_NONBLOCK);
> + fstat(STDIN_FILENO, &inf->sb);
> + return;
> + }
>
> retval = lstat(inf->path, &inf->sb);
> if (retval == -1) {
