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Message-ID: <6f01c382-8da5-5673-30db-0c0099d820b5@redhat.com>
Date:   Tue, 8 Feb 2022 11:04:21 -0500
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Subject: Re: [nfs-utils PATCH] nfs4id: a tool to create and persist nfs4
 client uniquifiers
Content-Language: en-US
To:     Benjamin Coddington <bcodding@redhat.com>
Cc:     linux-nfs@vger.kernel.org
References: <c2e8b7c06352d3cad3454de096024fff80e638af.1643979161.git.bcodding@redhat.com>
From:   Steve Dickson <steved@redhat.com>
In-Reply-To: <c2e8b7c06352d3cad3454de096024fff80e638af.1643979161.git.bcodding@redhat.com>
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Hello,

On 2/4/22 7:56 AM, Benjamin Coddington wrote:
> The nfs4id program will either create a new UUID from a random source or
> derive it from /etc/machine-id, else it returns a UUID that has already
> been written to /etc/nfs4-id.  This small, lightweight tool is suitable for
> execution by systemd-udev in rules to populate the nfs4 client uniquifier.
> 
> Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
> ---
>   .gitignore               |   1 +
>   configure.ac             |   4 +
>   tools/Makefile.am        |   1 +
>   tools/nfs4id/Makefile.am |   8 ++
>   tools/nfs4id/nfs4id.c    | 184 +++++++++++++++++++++++++++++++++++++++
>   tools/nfs4id/nfs4id.man  |  29 ++++++
>   6 files changed, 227 insertions(+)
>   create mode 100644 tools/nfs4id/Makefile.am
>   create mode 100644 tools/nfs4id/nfs4id.c
>   create mode 100644 tools/nfs4id/nfs4id.man
Just a nit... naming convention... In the past
we never put the protocol version in the name.
Do a ls tools and utils directory and you
see what I mean....

Would it be a problem to change the name from
nfs4id to nfsid?

steved.

> 
> diff --git a/.gitignore b/.gitignore
> index c89d1cd2583d..a37964148dd8 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -61,6 +61,7 @@ utils/statd/statd
>   tools/locktest/testlk
>   tools/getiversion/getiversion
>   tools/nfsconf/nfsconf
> +tools/nfs4id/nfs4id
>   support/export/mount.h
>   support/export/mount_clnt.c
>   support/export/mount_xdr.c
> diff --git a/configure.ac b/configure.ac
> index 50e9b321dcf3..93d0a902cfd8 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -355,6 +355,9 @@ if test "$enable_nfsv4" = yes; then
>     dnl check for the keyutils libraries and headers
>     AC_KEYUTILS
>   
> +  dnl check for the libuuid library and headers
> +  AC_LIBUUID
> +
>     dnl Check for sqlite3
>     AC_SQLITE3_VERS
>   
> @@ -740,6 +743,7 @@ AC_CONFIG_FILES([
>   	tools/nfsdclnts/Makefile
>   	tools/nfsconf/Makefile
>   	tools/nfsdclddb/Makefile
> +	tools/nfs4id/Makefile
>   	utils/Makefile
>   	utils/blkmapd/Makefile
>   	utils/nfsdcld/Makefile
> diff --git a/tools/Makefile.am b/tools/Makefile.am
> index 9b4b0803db39..cc658f69bb32 100644
> --- a/tools/Makefile.am
> +++ b/tools/Makefile.am
> @@ -7,6 +7,7 @@ OPTDIRS += rpcgen
>   endif
>   
>   OPTDIRS += nfsconf
> +OPTDIRS += nfs4id
>   
>   if CONFIG_NFSDCLD
>   OPTDIRS += nfsdclddb
> diff --git a/tools/nfs4id/Makefile.am b/tools/nfs4id/Makefile.am
> new file mode 100644
> index 000000000000..d1e60a35a510
> --- /dev/null
> +++ b/tools/nfs4id/Makefile.am
> @@ -0,0 +1,8 @@
> +## Process this file with automake to produce Makefile.in
> +
> +man8_MANS	= nfs4id.man
> +
> +bin_PROGRAMS = nfs4id
> +
> +nfs4id_SOURCES = nfs4id.c
> +nfs4id_LDADD = $(LIBUUID)
> diff --git a/tools/nfs4id/nfs4id.c b/tools/nfs4id/nfs4id.c
> new file mode 100644
> index 000000000000..dbb807ae21f3
> --- /dev/null
> +++ b/tools/nfs4id/nfs4id.c
> @@ -0,0 +1,184 @@
> +/*
> + * nfs4id.c -- create and persist uniquifiers for nfs4 clients
> + *
> + * Copyright (C) 2022  Red Hat, Benjamin Coddington <bcodding@redhat.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor,
> + * Boston, MA 02110-1301, USA.
> + */
> +
> +#include <stdio.h>
> +#include <stdarg.h>
> +#include <getopt.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <stdlib.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <uuid/uuid.h>
> +
> +#define NFS4IDFILE "/etc/nfs4-id"
> +
> +UUID_DEFINE(nfs4_clientid_uuid_template,
> +	0xa2, 0x25, 0x68, 0xb2, 0x7a, 0x5f, 0x49, 0x90,
> +	0x8f, 0x98, 0xc5, 0xf0, 0x67, 0x78, 0xcc, 0xf1);
> +
> +static char *prog;
> +static char *source = NULL;
> +static char nfs4_id[64];
> +static int force = 0;
> +
> +static void usage(void)
> +{
> +	fprintf(stderr, "usage: %s [-f|--force] [machine]\n", prog);
> +}
> +
> +static void fatal(const char *fmt, ...)
> +{
> +	int err = errno;
> +	va_list args;
> +	char fatal_msg[256] = "fatal: ";
> +
> +	va_start(args, fmt);
> +	vsnprintf(&fatal_msg[7], 255, fmt, args);
> +	if (err)
> +		fprintf(stderr, "%s: %s\n", fatal_msg, strerror(err));
> +	else
> +		fprintf(stderr, "%s\n", fatal_msg);
> +	exit(-1);
> +}
> +
> +static int read_nfs4_id(void)
> +{
> +	int fd;
> +
> +	fd = open(NFS4IDFILE, O_RDONLY);
> +	if (fd < 0)
> +		return fd;
> +	read(fd, nfs4_id, 64);
> +	close(fd);
> +	return 0;
> +}
> +
> +static void write_nfs4_id(void)
> +{
> +	int fd;
> +
> +	fd = open(NFS4IDFILE, O_RDWR|O_TRUNC|O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
> +	if (fd < 0)
> +		fatal("could not write id to " NFS4IDFILE);
> +	write(fd, nfs4_id, 37);
> +}
> +
> +static void print_nfs4_id(void)
> +{
> +	fprintf(stdout, "%s", nfs4_id);
> +}
> +	
> +static void check_or_make_id(void)
> +{
> +	int ret;
> +	uuid_t nfs4id_uuid;
> +
> +	ret = read_nfs4_id();
> +	if (ret != 0) {
> +		if (errno != ENOENT )
> +			fatal("reading file " NFS4IDFILE);
> +		uuid_generate_random(nfs4id_uuid);
> +		uuid_unparse(nfs4id_uuid, nfs4_id);
> +		nfs4_id[36] = '\n';
> +		nfs4_id[37] = '\0';
> +		write_nfs4_id();
> +	}
> +	print_nfs4_id();	
> +}
> +
> +static void check_or_make_id_from_machine(void)
> +{
> +	int fd, ret;
> +	char machineid[32];
> +	uuid_t nfs4id_uuid;
> +
> +	ret = read_nfs4_id();
> +	if (ret != 0) {
> +		if (errno != ENOENT )
> +			fatal("reading file " NFS4IDFILE);
> +
> +		fd = open("/etc/machine-id", O_RDONLY);
> +		if (fd < 0)
> +			fatal("unable to read /etc/machine-id");
> +
> +		read(fd, machineid, 32);
> +		close(fd);
> +
> +		uuid_generate_sha1(nfs4id_uuid, nfs4_clientid_uuid_template, machineid, 32);
> +		uuid_unparse(nfs4id_uuid, nfs4_id);
> +		nfs4_id[36] = '\n';
> +		nfs4_id[37] = '\0';
> +		write_nfs4_id();
> +	}
> +	print_nfs4_id();
> +}
> +
> +int main(int argc, char **argv)
> +{
> +	prog = argv[0];
> +
> +	while (1) {
> +		int opt;
> +		int option_index = 0;
> +		static struct option long_options[] = {
> +			{"force",	no_argument,	0, 'f' },
> +			{0,			0,				0, 0 }
> +		};
> +
> +		errno = 0;
> +		opt = getopt_long(argc, argv, ":f", long_options, &option_index);
> +		if (opt == -1)
> +			break;
> +
> +		switch (opt) {
> +		case 'f':
> +			force = 1;
> +			break;
> +		case '?':
> +			usage();
> +			fatal("unexpected arg \"%s\"", argv[optind - 1]);
> +			break;
> +		}
> +	}
> +
> +	argc -= optind;
> +
> +	if (argc > 1) {
> +		usage();
> +		fatal("Too many arguments");
> +	}
> +
> +	if (argc)
> +		source = argv[optind++];
> +
> +	if (force)
> +		unlink(NFS4IDFILE);
> +
> +	if (!source)
> +		check_or_make_id();
> +	else if (strcmp(source, "machine") == 0)
> +		check_or_make_id_from_machine();
> +	else {
> +		usage();
> +		fatal("unrecognized source %s\n", source);
> +	}
> +}
> diff --git a/tools/nfs4id/nfs4id.man b/tools/nfs4id/nfs4id.man
> new file mode 100644
> index 000000000000..358f836468a2
> --- /dev/null
> +++ b/tools/nfs4id/nfs4id.man
> @@ -0,0 +1,29 @@
> +.\"
> +.\" nfs4id(8)
> +.\"
> +.TH nfs4id 8 "3 Feb 2022"
> +.SH NAME
> +nfs4id \- Generate or return nfs4 client id uniqueifiers
> +.SH SYNOPSIS
> +.B nfs4id [ -f | --force ] [<source>]
> +
> +.SH DESCRIPTION
> +The
> +.B nfs4id
> +command provides a simple utility to help NFS Version 4 clients use unique
> +and persistent client id values.  The command checks for the existence of a
> +file /etc/nfs4-id and returns the first 64 chars read from that file.  If
> +the file is not found, a UUID is generated from the specified source and
> +written to the file and returned.
> +.SH OPTIONS
> +.TP
> +.BR \-f, \-\-force
> +Overwrite the existing /etc/nfs4-id with a UUID generated from <source>.
> +.SH Sources
> +If <source> is not specified, nfs4id will generate a new random UUID.
> +
> +If <source> is "machine", nfs4id will generate a deterministic UUID value
> +derived from a sha1 hash of the contents of /etc/machine-id and a static
> +key.
> +.SH SEE ALSO
> +.BR machine-id (5)