On 2024/04/15 19:48, Jeremie Courreges-Anglas wrote:
> 
> One drawback of switching tar(1) to use 'pax' write format by default
> is that tar(1) doesn't give the user a generic way to specify a format
> (-o and -O suck).  So the diff below uses -F for that.  GNU tar uses
> -H (already used) and FreeBSD/NetBSD tar use --format and we don't
> want long options.

-F seems a reasonable choice. It's used for "Run COMMAND at the end of
each tape" on gnu tar, I don't think it matters too much if we conflict
with that.

> -o handling becomes slightly brittle but I have plans to
>  butcher^Wimprove that option anyway.
> 
> Input and reviews welcome.  ok?

fwiw ok with me.

> 
> Index: options.c
> ===================================================================
> RCS file: /cvs/src/bin/pax/options.c,v
> diff -u -p -r1.108 options.c
> --- options.c	15 Apr 2024 17:33:10 -0000	1.108
> +++ options.c	15 Apr 2024 17:44:05 -0000
> @@ -725,9 +725,10 @@ static void
>  tar_options(int argc, char **argv)
>  {
>  	int c;
> -	int Oflag = 0;
>  	int nincfiles = 0;
>  	int incfiles_max = 0;
> +	unsigned int i;
> +	unsigned int format = F_TAR;
>  	struct incfile {
>  		char *file;
>  		char *dir;
> @@ -743,7 +744,7 @@ tar_options(int argc, char **argv)
>  	 * process option flags
>  	 */
>  	while ((c = getoldopt(argc, argv,
> -	    "b:cef:hjmopqruts:vwxzBC:HI:LNOPXZ014578")) != -1) {
> +	    "b:cef:hjmopqruts:vwxzBC:F:HI:LNOPXZ014578")) != -1) {
>  		switch (c) {
>  		case 'b':
>  			/*
> @@ -792,10 +793,10 @@ tar_options(int argc, char **argv)
>  			pmtime = 0;
>  			break;
>  		case 'O':
> -			Oflag = 1;
> +			format = F_OTAR;
>  			break;
>  		case 'o':
> -			Oflag = 2;
> +			format = F_OTAR;
>  			tar_nodir = 1;
>  			break;
>  		case 'p':
> @@ -868,6 +869,24 @@ tar_options(int argc, char **argv)
>  			havechd++;
>  			chdname = optarg;
>  			break;
> +		case 'F':
> +			for (i = 0; i < sizeof(fsub)/sizeof(FSUB); ++i)
> +				if (fsub[i].name != NULL &&
> +				    strcmp(fsub[i].name, optarg) == 0)
> +					break;
> +			if (i < sizeof(fsub)/sizeof(FSUB)) {
> +				format = i;
> +				break;
> +			}
> +			paxwarn(1, "Unknown -F format: %s", optarg);
> +			(void)fputs("tar: Known -F formats are:", stderr);
> +			for (i = 0; i < (sizeof(fsub)/sizeof(FSUB)); ++i)
> +				if (fsub[i].name != NULL)
> +					(void)fprintf(stderr, " %s",
> +					    fsub[i].name);
> +			(void)fputs("\n\n", stderr);
> +			tar_usage();
> +			break;
>  		case 'H':
>  			/*
>  			 * follow command line symlinks only
> @@ -1042,7 +1061,7 @@ tar_options(int argc, char **argv)
>  		break;
>  	case ARCHIVE:
>  	case APPND:
> -		frmt = &(fsub[Oflag ? F_OTAR : F_TAR]);
> +		frmt = &fsub[format];
>  
>  		if (chdname != NULL) {	/* initial chdir() */
>  			if (ftree_add(chdname, 1) < 0)
> @@ -1704,11 +1723,12 @@ void
>  tar_usage(void)
>  {
>  	(void)fputs(
> -	    "usage: tar {crtux}[014578befHhjLmNOoPpqsvwXZz]\n"
> -	    "           [blocking-factor | archive | replstr] [-C directory] [-I file]\n"
> -	    "           [file ...]\n"
> +	    "usage: tar {crtux}[014578beFfHhjLmNOoPpqsvwXZz]\n"
> +	    "           [blocking-factor | format | archive | replstr]\n"
> +	    "           [-C directory] [-I file] [file ...]\n"
>  	    "       tar {-crtux} [-014578eHhjLmNOoPpqvwXZz] [-b blocking-factor]\n"
> -	    "           [-C directory] [-f archive] [-I file] [-s replstr] [file ...]\n",
> +	    "           [-C directory] [-F format] [-f archive] [-I file]\n"
> +	    "           [-s replstr] [file ...]\n",
>  	    stderr);
>  	exit(1);
>  }
> Index: tar.1
> ===================================================================
> RCS file: /cvs/src/bin/pax/tar.1,v
> diff -u -p -r1.65 tar.1
> --- tar.1	3 Aug 2023 18:17:54 -0000	1.65
> +++ tar.1	15 Apr 2024 17:44:05 -0000
> @@ -32,10 +32,10 @@
>  .Sh SYNOPSIS
>  .Nm tar
>  .Sm off
> -.No { Cm crtux No } Op Cm 014578befHhjLmNOoPpqsvwXZz
> +.No { Cm crtux No } Op Cm 014578beFfHhjLmNOoPpqsvwXZz
>  .Sm on
>  .Bk -words
> -.Op Ar blocking-factor | archive | replstr
> +.Op Ar blocking-factor | format | archive | replstr
>  .Op Fl C Ar directory
>  .Op Fl I Ar file
>  .Op Ar
> @@ -46,6 +46,7 @@
>  .Op Fl 014578eHhjLmNOoPpqvwXZz
>  .Op Fl b Ar blocking-factor
>  .Op Fl C Ar directory
> +.Op Fl F Ar format
>  .Op Fl f Ar archive
>  .Op Fl I Ar file
>  .Op Fl s Ar replstr
> @@ -141,6 +142,77 @@ the specified directory; when creating, 
>  from the directory.
>  .It Fl e
>  Stop after the first error.
> +.It Fl F Ar format
> +Specify the output archive format, with the default format being
> +.Cm ustar .
> +.Nm
> +currently supports the following formats:
> +.Bl -tag -width "sv4cpio"
> +.It Cm bcpio
> +The old binary cpio format.
> +The default blocksize for this format is 5120 bytes.
> +This format is not very portable and should not be used when other formats
> +are available.
> +Inode and device information about a file (used for detecting file hard links
> +by this format), which may be truncated by this format, is detected by
> +.Nm
> +and is repaired.
> +.It Cm cpio
> +The extended cpio interchange format specified in the
> +.St -p1003.2
> +standard.
> +The default blocksize for this format is 5120 bytes.
> +Inode and device information about a file (used for detecting file hard links
> +by this format), which may be truncated by this format, is detected by
> +.Nm
> +and is repaired.
> +.It Cm sv4cpio
> +The System V release 4 cpio.
> +The default blocksize for this format is 5120 bytes.
> +Inode and device information about a file (used for detecting file hard links
> +by this format), which may be truncated by this format, is detected by
> +.Nm
> +and is repaired.
> +.It Cm sv4crc
> +The System V release 4 cpio with file CRC checksums.
> +The default blocksize for this format is 5120 bytes.
> +Inode and device information about a file (used for detecting file hard links
> +by this format), which may be truncated by this format, is detected by
> +.Nm
> +and is repaired.
> +.It Cm tar
> +The old
> +.Bx
> +tar format as found in
> +.Bx 4.3 .
> +The default blocksize for this format is 10240 bytes.
> +Pathnames stored by this format must be 100 characters or less in length.
> +Only regular files, hard links, soft links, and directories
> +will be archived (other file system types are not supported).
> +For backwards compatibility with even older tar formats, see the
> +description for
> +.Fl o .
> +.It Cm ustar
> +The extended tar interchange format specified in the
> +.St -p1003.2
> +standard.
> +The default blocksize for this format is 10240 bytes.
> +Filenames stored by this format must be 100 characters or less in length;
> +the total pathname must be 256 characters or less.
> +.It Cm pax
> +The pax interchange format specified in the
> +.St -p1003.1-2001
> +standard.
> +The default blocksize for this format is 5120 bytes.
> +.El
> +.Pp
> +.Nm
> +will detect and report any file that it is unable to store or extract
> +as the result of any specific archive format restrictions.
> +The individual archive formats may impose additional restrictions on use.
> +Typical archive format restrictions include (but are not limited to):
> +file pathname length, file size, link pathname length, and the type of the
> +file.
>  .It Fl f Ar archive
>  Read from or write to
>  .Ar archive .
> 
> -- 
> jca
>