> On Feb 10, 2022, at 1:01 PM, Benjamin Coddington <[email protected]> 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.
Possible alternatives:
nfshostuniquifier
nfsuniquehost
nfshostuuid
> Signed-off-by: Benjamin Coddington <[email protected]>
> ---
> .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 <[email protected]>
> + *
> + * 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
On 2/10/22 1:15 PM, Chuck Lever III wrote:
>
>
>> On Feb 10, 2022, at 1:01 PM, Benjamin Coddington <[email protected]> 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/[email protected]/T/#mdb6af27181ed912ed2220208dea9ca8711937864
>
>
>> Signed-off-by: Benjamin Coddington <[email protected]>
>> ---
>> .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 <[email protected]>
>> + *
>> + * 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
>
>
>