c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2026-05-22 02:27:36 +03:00
Code Issues Packages Projects Releases Wiki Activity

cmd/zgenhostid: replace with simple c implementation

Browse Source 
It was discovered that dracut scripts and zgenhostid
always generate little-endian /etc/hostid.

This commit provides simple endianess-aware binary
and updates the scripts to use it.

New features include:
 -f flag to force overwrite.
 -o flag to write to different file (for dracut)
 accepting both 0x01234567 and 01234567 values as input

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Signed-off-by: Georgy Yakovlev <gyakovlev@gentoo.org>
Closes #10887 
Closes #10925
This commit is contained in:
Georgy Yakovlev
2020-09-16 12:25:12 -07:00
committed by GitHub
parent 9569c31161
commit 9cc177baa0
7 changed files with 213 additions and 93 deletions
Download Patch File Download Diff File Expand all files Collapse all files
cmd/zgenhostid/.gitignore
+1
View File
@@ -0,0 +1 @@
/zgenhostid
cmd/zgenhostid/Makefile.am
+5 -1
View File
@@ -1 +1,5 @@
dist_bin_SCRIPTS = zgenhostid
include $(top_srcdir)/config/Rules.am
bin_PROGRAMS = zgenhostid
zgenhostid_SOURCES = zgenhostid.c
cmd/zgenhostid/zgenhostid
-61
View File
@@ -1,61 +0,0 @@
#!/usr/bin/env bash
# Emulate genhostid(1) available on RHEL/CENTOS, for use on distros
# which do not provide that utility.
#
# Usage:
# zgenhostid
# zgenhostid <value>
#
# If /etc/hostid already exists and is size > 0, the script exits immediately
# and changes nothing. Unlike genhostid, this generates an error message.
#
# The first form generates a random hostid and stores it in /etc/hostid.
# The second form checks that the provided value is between 0x1 and 0xFFFFFFFF
# and if so, stores it in /etc/hostid. This form is not supported by
# genhostid(1).
hostid_file=/etc/hostid
function usage {
echo "$0 [value]"
echo "If $hostid_file is not present, store a hostid in it." >&2
echo "The optional value must be an 8-digit hex number between" >&2
echo "1 and 2^32-1. If no value is provided, a random one will" >&2
echo "be generated. The value must be unique among your systems." >&2
}
# hostid(1) ignores contents of /etc/hostid if size < 4 bytes. It would
# be better if this checked size >= 4 bytes but it the method must be
# widely portable.
if [ -s $hostid_file ]; then
echo "$hostid_file already exists. No change made." >&2
exit 1
fi
if [ -n "$1" ]; then
host_id=$1
else
# $RANDOM goes from 0..32k-1
number=$((((RANDOM % 4) * 32768 + RANDOM) * 32768 + RANDOM))
host_id=$(printf "%08x" $number)
fi
if egrep -o '^0{8}$' <<< $host_id >/dev/null 2>&1; then
usage
exit 2
fi
if ! egrep -o '^[a-fA-F0-9]{8}$' <<< $host_id >/dev/null 2>&1; then
usage
exit 3
fi
a=${host_id:6:2}
b=${host_id:4:2}
c=${host_id:2:2}
d=${host_id:0:2}
echo -ne \\x$a\\x$b\\x$c\\x$d > $hostid_file
exit 0
cmd/zgenhostid/zgenhostid.c
+152
View File
@@ -0,0 +1,152 @@
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2020, Georgy Yakovlev. All rights reserved.
*/
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <inttypes.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
static void usage(void);
static void
usage(void)
{
(void) fprintf(stderr,
"usage: zgenhostid [-fh] [-o path] [value]\n\n"
" -f\t\t force hostid file write\n"
" -h\t\t print this usage and exit\n"
" -o <filename>\t write hostid to this file\n\n"
"If hostid file is not present, store a hostid in it.\n"
"The optional value must be an 8-digit hex number between"
"1 and 2^32-1.\n"
"If no value is provided, a random one will"
"be generated.\n"
"The value must be unique among your systems.\n");
exit(EXIT_FAILURE);
/* NOTREACHED */
}
int
main(int argc, char **argv)
{
/* default file path, can be optionally set by user */
char path[PATH_MAX] = "/etc/hostid";
/* holds converted user input or lrand48() generated value */
unsigned long input_i = 0;
int opt;
int pathlen;
int force_fwrite = 0;
while ((opt = getopt_long(argc, argv, "fo:h?", 0, 0)) != -1) {
switch (opt) {
case 'f':
force_fwrite = 1;
break;
case 'o':
pathlen = snprintf(path, sizeof (path), "%s", optarg);
if (pathlen >= sizeof (path)) {
fprintf(stderr, "%s\n", strerror(EOVERFLOW));
exit(EXIT_FAILURE);
} else if (pathlen < 1) {
fprintf(stderr, "%s\n", strerror(EINVAL));
exit(EXIT_FAILURE);
}
break;
case 'h':
case '?':
usage();
}
}
char *in_s = argv[optind];
if (in_s != NULL) {
/* increment pointer by 2 if string is 0x prefixed */
if (strncasecmp("0x", in_s, 2) == 0) {
in_s += 2;
}
/* need to be exactly 8 characters */
const char *hex = "0123456789abcdefABCDEF";
if (strlen(in_s) != 8 || strspn(in_s, hex) != 8) {
fprintf(stderr, "%s\n", strerror(ERANGE));
usage();
}
input_i = strtoul(in_s, NULL, 16);
if (errno != 0) {
perror("strtoul");
exit(EXIT_FAILURE);
}
if (input_i < 0x1 || input_i > UINT32_MAX) {
fprintf(stderr, "%s\n", strerror(ERANGE));
usage();
}
}
struct stat fstat;
if (force_fwrite == 0 && stat(path, &fstat) == 0 &&
S_ISREG(fstat.st_mode)) {
fprintf(stderr, "%s: %s\n", path, strerror(EEXIST));
exit(EXIT_FAILURE);
}
/*
* generate if not provided by user
* also handle unlikely zero return from lrand48()
*/
while (input_i == 0) {
srand48(getpid() ^ time(NULL));
input_i = lrand48();
}
FILE *fp = fopen(path, "wb");
if (!fp) {
perror("fopen");
exit(EXIT_FAILURE);
}
/*
* we need just 4 bytes in native endianess
* not using sethostid() because it may be missing or just a stub
*/
uint32_t hostid = input_i;
int written = fwrite(&hostid, 1, 4, fp);
if (written != 4) {
perror("fwrite");
exit(EXIT_FAILURE);
}
fclose(fp);
exit(EXIT_SUCCESS);
}