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Message-ID: <3d2992df-7ef7-50ba-4f11-f4de588620d2@redhat.com>
Date:   Fri, 11 Feb 2022 08:44:55 -0500
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Subject: Re: [PATCH v2 1/2] nfsuuid: a tool to create and persist nfs4 client
 uniquifiers
Content-Language: en-US
To:     Chuck Lever III <chuck.lever@oracle.com>,
        Benjamin Coddington <bcodding@redhat.com>
Cc:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>
References: <cover.1644515977.git.bcodding@redhat.com>
 <9c046648bfd9c8260ec7bd37e0a93f7821e0842f.1644515977.git.bcodding@redhat.com>
 <7642FA55-F3F2-4813-86E2-1B65185E6B36@oracle.com>
From:   Steve Dickson <steved@redhat.com>
In-Reply-To: <7642FA55-F3F2-4813-86E2-1B65185E6B36@oracle.com>
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On 2/10/22 1:15 PM, Chuck Lever III wrote:
> 
> 
>> On Feb 10, 2022, at 1:01 PM, Benjamin Coddington <bcodding@redhat.com> wrote:
>>
>> The nfsuuid 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/nfsuuid or the file specified.  This small,
>> lightweight tool is suitable for execution by systemd-udev in rules to
>> populate the nfs4 client uniquifier.
> 
> I like everything but the name. Without context, even if
> I read NFS protocol specifications, I have no idea what
> "nfsuuid" does.
man nfsuuid :-)
> 
> Possible alternatives:
> 
> nfshostuniquifier
> nfsuniquehost
> nfshostuuid
I'm good with the name... short sweet and easy to type.
The name a command does not have to explain what it does. IMHO.

I think what is more concerning is addressing
Neil's concern as to why we even using udev [1].

steved.

[1] 
https://lore.kernel.org/all/0AB20C82-6200-46E0-A76C-62345DAF8A3A@redhat.com/T/#mdb6af27181ed912ed2220208dea9ca8711937864
> 
> 
>> Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
>> ---
>> .gitignore                |   1 +
>> aclocal/libuuid.m4        |  17 ++++
>> configure.ac              |   4 +
>> tools/Makefile.am         |   1 +
>> tools/nfsuuid/Makefile.am |   8 ++
>> tools/nfsuuid/nfsuuid.c   | 203 ++++++++++++++++++++++++++++++++++++++
>> tools/nfsuuid/nfsuuid.man |  33 +++++++
>> 7 files changed, 267 insertions(+)
>> create mode 100644 aclocal/libuuid.m4
>> create mode 100644 tools/nfsuuid/Makefile.am
>> create mode 100644 tools/nfsuuid/nfsuuid.c
>> create mode 100644 tools/nfsuuid/nfsuuid.man
>>
>> diff --git a/.gitignore b/.gitignore
>> index c89d1cd2583d..4d63ee93b2dc 100644
>> --- a/.gitignore
>> +++ b/.gitignore
>> @@ -61,6 +61,7 @@ utils/statd/statd
>> tools/locktest/testlk
>> tools/getiversion/getiversion
>> tools/nfsconf/nfsconf
>> +tools/nfsuuid/nfsuuid
>> support/export/mount.h
>> support/export/mount_clnt.c
>> support/export/mount_xdr.c
>> diff --git a/aclocal/libuuid.m4 b/aclocal/libuuid.m4
>> new file mode 100644
>> index 000000000000..f64085010d1d
>> --- /dev/null
>> +++ b/aclocal/libuuid.m4
>> @@ -0,0 +1,17 @@
>> +AC_DEFUN([AC_LIBUUID], [
>> +        LIBUUID=
>> +
>> +        AC_CHECK_LIB([uuid], [uuid_generate_random], [], [AC_MSG_FAILURE(
>> +                [Missing libuuid uuid_generate_random, needed to build nfs4id])])
>> +
>> +        AC_CHECK_LIB([uuid], [uuid_generate_sha1], [], [AC_MSG_FAILURE(
>> +                [Missing libuuid uuid_generate_sha1, needed to build nfs4id])])
>> +
>> +        AC_CHECK_LIB([uuid], [uuid_unparse], [], [AC_MSG_FAILURE(
>> +                [Missing libuuid uuid_unparse, needed to build nfs4id])])
>> +
>> +        AC_CHECK_HEADER([uuid/uuid.h], [], [AC_MSG_FAILURE(
>> +                [Missing uuid/uuid.h, needed to build nfs4id])])
>> +
>> +        AC_SUBST([LIBUUID], ["-luuid"])
>> +])
>> diff --git a/configure.ac b/configure.ac
>> index 50e9b321dcf3..1342c471f142 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/nfsuuid/Makefile
>> 	utils/Makefile
>> 	utils/blkmapd/Makefile
>> 	utils/nfsdcld/Makefile
>> diff --git a/tools/Makefile.am b/tools/Makefile.am
>> index 9b4b0803db39..a12b0f34f4e7 100644
>> --- a/tools/Makefile.am
>> +++ b/tools/Makefile.am
>> @@ -7,6 +7,7 @@ OPTDIRS += rpcgen
>> endif
>>
>> OPTDIRS += nfsconf
>> +OPTDIRS += nfsuuid
>>
>> if CONFIG_NFSDCLD
>> OPTDIRS += nfsdclddb
>> diff --git a/tools/nfsuuid/Makefile.am b/tools/nfsuuid/Makefile.am
>> new file mode 100644
>> index 000000000000..7b3a54c30d50
>> --- /dev/null
>> +++ b/tools/nfsuuid/Makefile.am
>> @@ -0,0 +1,8 @@
>> +## Process this file with automake to produce Makefile.in
>> +
>> +man8_MANS	= nfsuuid.man
>> +
>> +bin_PROGRAMS = nfsuuid
>> +
>> +nfsuuid_SOURCES = nfsuuid.c
>> +nfsuuid_LDADD = $(LIBUUID)
>> diff --git a/tools/nfsuuid/nfsuuid.c b/tools/nfsuuid/nfsuuid.c
>> new file mode 100644
>> index 000000000000..bbdec59f1afe
>> --- /dev/null
>> +++ b/tools/nfsuuid/nfsuuid.c
>> @@ -0,0 +1,203 @@
>> +/*
>> + * nfsuuid.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 DEFAULT_ID_FILE "/etc/nfsuuid"
>> +
>> +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 *id_file = DEFAULT_ID_FILE;
>> +static char nfs_unique_id[64];
>> +static int replace = 0;
>> +
>> +static void usage(void)
>> +{
>> +	fprintf(stderr, "usage: %s [-r|--replace] [-f <file> |--file <file> ] [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_nfs_unique_id(void)
>> +{
>> +	int fd;
>> +	ssize_t len;
>> +
>> +	if (replace) {
>> +		errno = ENOENT;
>> +		return -1;
>> +	}
>> +
>> +	fd = open(id_file, O_RDONLY);
>> +	if (fd < 0)
>> +		return fd;
>> +	len = read(fd, nfs_unique_id, 64);
>> +	close(fd);
>> +	return len;
>> +}
>> +
>> +static void write_nfs_unique_id(void)
>> +{
>> +	int fd;
>> +
>> +	fd = open(id_file, O_RDWR|O_TRUNC|O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
>> +	if (fd < 0)
>> +		fatal("could not write id to %s", id_file);
>> +	write(fd, nfs_unique_id, 37);
>> +}
>> +
>> +static void print_nfs_unique_id(void)
>> +{
>> +	fprintf(stdout, "%s", nfs_unique_id);
>> +}
>> +
>> +static void check_or_make_id(void)
>> +{
>> +	int ret;
>> +	uuid_t uuid;
>> +
>> +	ret = read_nfs_unique_id();
>> +	if (ret < 1) {
>> +		if (errno != ENOENT )
>> +			fatal("reading file %s", id_file);
>> +		uuid_generate_random(uuid);
>> +		uuid_unparse(uuid, nfs_unique_id);
>> +		nfs_unique_id[36] = '\n';
>> +		nfs_unique_id[37] = '\0';
>> +		write_nfs_unique_id();
>> +	}
>> +	print_nfs_unique_id();
>> +}
>> +
>> +static void check_or_make_id_from_machine(void)
>> +{
>> +	int fd, ret;
>> +	char machineid[32];
>> +	uuid_t uuid;
>> +
>> +	ret = read_nfs_unique_id();
>> +	if (ret < 1) {
>> +		if (errno != ENOENT )
>> +			fatal("reading file %s", id_file);
>> +
>> +		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(uuid, nfs4_clientid_uuid_template, machineid, 32);
>> +		uuid_unparse(uuid, nfs_unique_id);
>> +		nfs_unique_id[36] = '\n';
>> +		nfs_unique_id[37] = '\0';
>> +		write_nfs_unique_id();
>> +	}
>> +	print_nfs_unique_id();
>> +}
>> +
>> +int main(int argc, char **argv)
>> +{
>> +	prog = argv[0];
>> +
>> +	while (1) {
>> +		int opt, prev_ind;
>> +		int option_index = 0;
>> +		static struct option long_options[] = {
>> +			{"replace",	no_argument,		0, 'r' },
>> +			{"file",	required_argument,	0, 'f' },
>> +			{ 0, 0, 0, 0 }
>> +		};
>> +
>> +		errno = 0;
>> +		prev_ind = optind;
>> +		opt = getopt_long(argc, argv, ":rf:", long_options, &option_index);
>> +		if (opt == -1)
>> +			break;
>> +
>> +		/* Let's detect missing options in the middle of an option list */
>> +		if (optind == prev_ind + 2 && *optarg == '-') {
>> +			opt = ':';
>> +			--optind;
>> +		}
>> +
>> +		switch (opt) {
>> +		case 'r':
>> +			replace = 1;
>> +			break;
>> +		case 'f':
>> +			id_file = optarg;
>> +			break;
>> +		case ':':
>> +			usage();
>> +			fatal("option \"%s\" requires an argument", argv[prev_ind]);
>> +			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 (!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/nfsuuid/nfsuuid.man b/tools/nfsuuid/nfsuuid.man
>> new file mode 100644
>> index 000000000000..856d2f383e0f
>> --- /dev/null
>> +++ b/tools/nfsuuid/nfsuuid.man
>> @@ -0,0 +1,33 @@
>> +.\"
>> +.\" nfsuuid(8)
>> +.\"
>> +.TH nfsuuid 8 "10 Feb 2022"
>> +.SH NAME
>> +nfsuuid \- Generate or return nfs client id uniquifiers
>> +.SH SYNOPSIS
>> +.B nfsuuid [ -r | --replace ] [ -f | --file <file> ] [<source>]
>> +
>> +.SH DESCRIPTION
>> +The
>> +.B nfsuuid
>> +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/nfsuuid 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 \-r,\ \-\-replace
>> +Overwrite the <file> with a UUID generated from <source>.
>> +.TP
>> +.BR \-f,\ \-\-file
>> +Use the specified file to lookup or store any generated UUID.  If <file> is
>> +not specified, the default file used is /etc/nfsuuid.
>> +.SH Sources
>> +If <source> is not specified, nfsuuid will generate a new random UUID.
>> +
>> +If <source> is "machine", nfsuuid 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)
>> -- 
>> 2.31.1
>>
> 
> --
> Chuck Lever
> 
> 
>