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|
#!/usr/bin/perl -w
# Copyright: 2024-2025 Lorenzo Puliti <plorenzo@disroot.org>
# License: BSD-3-clause
# minsysusers version: 0.2
use 5.012;
use strict;
use warnings;
sub usage {print STDERR "usage: minsysusers [--root=/path] file.conf [ file2.conf ... ]\n"; return 1;}
sub error {print STDERR "error: $_[0]\n"; return 1;}
sub warning {print "warning: $_[0]\n"; return 0;}
#TODO standardize error for invalid field with a sub
unless (@ARGV) {exit usage;}
my $changeroot = 0; my $rcounter = 0; my $usergroup = 0; my $debug = 0;
my $root="";
my $conf;
my $prefix='--prefix=/';
my $name; my $id; my $gecos=""; my $home='/'; my $shell='/sbin/nologin';
my $gid; my $groupname; my $groupid; #TODO RM groupid
my $upath="0"; my $gpath="0";
my $rmin; my $rmax; my $range=""; my $lrange=""; my @rmins = (); my @rmaxs = (); #TODO RM range lrange?
my @conffiles = ();
my @args = ();
my @ulines = (); my @glines = (); my @mlines = (); my @rlines = ();
while (@ARGV) {
my $arg = shift @ARGV;
#print "arg is $arg\n";#debug
if ($arg=~/^--root=(.*)$/) {
exit usage if "$changeroot";
$changeroot = 1; #TODO: more than one root= are possible with systemd-sysusers
$root = $1 ;
}
elsif ($arg=~/^--root$/) {
exit usage if "$changeroot";
$changeroot = 1 ; $arg = shift @ARGV; $root = $arg;
}
elsif ($arg=~/^-(.*)$/) {
print STDERR "Unknown option: $arg\n";
exit usage;
}
else {
push(@conffiles, $arg);
last unless (@ARGV)
}
}
unless (@conffiles) {exit usage;}
if ($changeroot) {
#print "change root requested\n"; print "root is $root\n";#debug
if ( ! -d "$root") {exit error("root directory not found:");}
$prefix = "--prefix=$root";
}
#print "conffiles are @conffiles \n";#debug
if ( -e "/etc/minsysusers.debug") {$debug = 1;}
sub is_reserved {# is_reserved($id)
my $num = "$_[0]"; return 0 unless ($num =~ /^[0-9]+$/);# ok, not numeric (groupname)
if ( "$num" eq "" ) { return 0; };#ok, blank
if ( "$num" =='65535' or "$num" =='4294967295' ) { return 1; };#reserved
return 0; #ok
}
sub is_number {# is_number($var)
my $num = "$_[0]";
if ($num =~ /^[0-9]+$/) {return 1}; return 0;
}
sub is_path {# is_path($var) #approximated with "starts with /"
my $slash = "$_[0]";
if ($slash =~ /^\/(.*)$/) {return 1}; return 0;
}
sub set_home_shell {#set_home_shell(fieldhome, fieldshell)
if (length "$_[0]") { $home="$_[0]" unless ("$_[0]" eq "-"); } #WARN: uninitialized value $_[0] with gecos as - and home unset
if (length "$_[1]") { $shell="$_[1]" unless ("$_[1]" eq "-"); }
exit error ("u: $home: path expected") unless (is_path($home));
exit error ("u: $shell: path expected") unless (is_path($shell));
#if (defined "$_[0]") { $home="$_[0]" unless ("$_[0]" eq "-"); }
#if (defined "$_[1]") { $shell="$_[1]" unless ("$_[1]" eq "-"); }
}
sub match_name {#match_name(file, name) looks in 1st field of /etc/passwd ||/etc/group for a name match
my $file = "$_[0]"; my $pattern = "$_[1]";
open (my $F, '<', "$file") or die "failed to open $file: $!";
while (my $fline = <$F>) {
if ($fline =~ /^\Q$pattern\E:(.*)$/) {
if ($debug) {print " $file: $pattern matched in $fline ";}#debug
close $F; return 1
}
}
close $F; return 0
}
sub match_uid {#match_uid(file, uid/gid): looks in 3rd field of /etc/passwd || /etc/group for a uid || gid match
my $file = "$_[0]"; my $pattern = "$_[1]"; #print " pattern is $pattern\n"; print "file is $file\n ";#debug
open (my $F, '<', "$file") or die "failed to open $file: $!";
while (my $fline = <$F>) {
if ($fline =~ /^(.*):(.*):\Q$pattern\E:(.*)$/) {
if ($debug) {print " $file: $pattern matched in $fline ";}#debug
close $F; return 1
}
}
close $F; return 0
}
for (@conffiles) {
my $usrconf = $_;
if ( -f "$root/etc/sysusers.d/$usrconf") {
$conf="$root/etc/sysusers.d/$usrconf";
}
elsif ( -l "$root/etc/sysusers.d/$usrconf") {
my $symtarget = readlink "$root/etc/sysusers.d/$usrconf";
if ($symtarget eq '/dev/null') {warning ("$usrconf: skipping, disabled via /dev/null link"); next;};
}
elsif ( -f "$root/usr/lib/sysusers.d/$usrconf") {
$conf="$root/usr/lib/sysusers.d/$usrconf";
}
else {
print STDERR "$usrconf : file not found\n"; exit 1;
}
#print "selected conffile path is $conf\n";#debug
open(my $fh, '<', "$conf") or do { exit error ("failed to open $conf"); };
while( my $line = <$fh>) {
chomp $line; my @types = split " " , $line, 2;
if ($types[0]) {
for($types[0]) {
if (/^#(.*)$/) { next; print "comment line, skipping\n" }
elsif (/^u$/ or /^u!$/) {# create user and group (account disabled) if they do not exist
push(@ulines, $line);
}
elsif (/^g$/) {# create system group, no pwd set, if it does not exist
push(@glines, $line);
}
elsif (/^m$/) {#create user or group if they do not exist
push(@mlines, $line);
}
elsif (/^r$/) {# tweak SYSGID/UID pool range
push(@rlines, $line);
}
else { warning ("invalid line: $line") }
}
}
}
close $fh;
if (@rlines) {#TODO: systemd-sysuser: with more than one of r lines multiple ranges are used, starting from higher value, but
# this is not feasible with useradd groupadd soo.. we take only one r line an discards the rest with warnings?
# maybe if the call to useradd fails we can try another range if there is more than one..
for (@rlines) {
if ($rcounter) { warning ("r line ignored, only one line supported");} ;
$rcounter = 1;#NOTE: can't pass multiple ranges to useradd/groupadd, so accept only the first one, stash the rest
my $rline = $_; my @fields = split " " , $rline;
if ($debug) {print "line is: $rline\n";}#debug
$name = $fields[1]; exit error ("r type: invalid name field, - expected") unless ($name eq "-");
$id = $fields[2]; if ($id eq "" || $id eq "-") { exit error ("r type: missing or invalid id field");}
if ($id =~ /^([0-9]+)-([0-9]+)$/) { #range
$rmin=$1; $rmax=$2;
}
elsif (is_number($id)) { #num # NOTE: overridden by each line id; otherwise fails if there are no available uid/gid left!
$rmin=$id; $rmax=$id;
}
else { exit error ("r type: invalid id field, digit expected")}
if (is_reserved($rmin)) { exit error (" invalid value: id 65535 and 4294967295 are reserved")};
if (is_reserved($rmax)) { exit error (" invalid value: id 65535 and 4294967295 are reserved")};
push(@rmins, $rmin); push(@rmaxs, $rmax);
#####$range= "-K SYS_UID_MIN=$rmin -K SYS_UID_MAX=$rmax -K SYS_GID_MIN=$rmin -K SYS_GID_MAX=$rmax"; #TODO RM
if ($debug) {print "name is: $name\n"; print "range is: $range\n"; print "rmin is: $rmin\n"; print "rmax is: $rmax\n";}#debug
$name =""; $id=""; $rmin=""; $rmax=""; #@fields = ();
if ($debug) {print "\n"; print "\n";}#debug
}
}
if (@glines) {
for (@glines) {
my $gline = $_; my @fields = split " " , $gline;
if ($debug) {print "line is: $gline\n";}#debug
$name = $fields[1]; if ($name eq "" || $name eq "-") { exit error ("u type: missing or invalid name field");}
#print "name is $name\n";#debug
if (match_name("$root/etc/group", "$name")) {print "$name group already exists, skipping line\n"; next;}
#ID NOTE: id: if defined, can be gid (numeric) or /path/to/fileordir (no uid:gid, no groupname for g lines)
if (defined $fields[2]) {
if ($fields[2] eq "-") { # auto alloc of gid
$id="";
}
elsif (is_number($fields[2])) { #numeric gid
$id=$fields[2];
if (match_uid("$root/etc/group", "$id")) {$id="";} #gid already taken, fallback to auto alloc
}
elsif (is_path($fields[2])) { #path
$id = (stat("$root/$fields[2]"))[5]; #NOTE: [4] = uid, [5]= gid, use gid for g lines
if ( defined $id) { #stat returns empty list if it falis
if (match_uid("$root/etc/group", "$id")) {$id="";} #gid already taken, fallback to auto alloc
}
else {$id="";}#NOTE: path not found/stat failed, fallback to auto id allocaltion
}
else {exit error ("g: id: invalid field value $fields[2]");}
}
else { $id=""; }
if (is_reserved($id)) { exit error ("invalid value: id 65535 and 4294967295 are reserved")}
if ($debug) {print "name: $name\n"; print "id: $id\n";}#debug
if ($debug) {print "COMMAND is: \n";}#debug
if ($id ne "") { #NOTE: line id prevails over r line range
if ($debug) {print "groupadd $prefix -r -g$id $name\n"};
system('groupadd', "$prefix", '-r', "-g$id", "$name");
}
elsif ($rcounter) {
if ($debug) {print "groupadd $prefix -r -KSYS_GID_MIN=$rmins[0] -KSYS_GID_MAX=$rmaxs[0] $name\n"};
system('groupadd', "$prefix", '-r', "-KSYS_GID_MIN=$rmins[0]", "-KSYS_GID_MAX=$rmaxs[0]", "$name");
}
else {
if ($debug) {print "groupadd $prefix -r $name\n"};
system('groupadd', "$prefix", '-r', "$name");
}
$name =""; $id=""; $gid=""; $lrange=""; #@fields = ();
if ($debug) {print "\n"; print "\n";}#debug
}
}
if (@ulines) {
for (@ulines) {
my $uline = $_; my @fields = split " " , $uline;
if ($debug) {print "line is: $uline\n";}#debug
$name = $fields[1]; if ($name eq "" || $name eq "-") { exit error ("u type: missing or invalid name field");}
#NOTE: we don't check if group name exists, group invocation is just skipped if user name exist
if (match_name("$root/etc/passwd", "$name")) {print "$name user already exists, skipping line\n"; next;}
if ($name eq "root") {$id="0"; $home = "/root"; $shell="/bin/sh"}#NOTE change default for root special case
# ID can be: uid(numeric); uid:gid (numeric); uid(numeric):groupname; /path/to/fileordir--> get both uid and gid
if (defined $fields[2]) {
if ($fields[2] eq "-") { #auto allocation
$id="";$gid=""; $lrange="$range"; $usergroup = 0;
}
elsif (is_number($fields[2])) { #uid (numeric)
$id=$fields[2]; $gid="";$lrange="-u $id"; $usergroup = 0;
if (match_uid("$root/etc/passwd", "$id")) {$id=""; $gid=""; $lrange="$range"; $usergroup = 0;} #id already taken in system, fallback to auto allocation
}
elsif ($fields[2] =~ /^(.*):(.*)$/) { # uid:gid || uid:groupname || -:gid || -:groupname
$id=$1 ; $gid = $2; $usergroup = 0; #GID/groupname must already exist
#GID
if (is_number($gid)) {
exit error ("u: $gid: gid not found in system") unless (match_uid("$root/etc/group", "$gid"));
}
else { #groupname
exit error ("u: $gid: invalid id field, gid or groupname expected") if ($gid eq "-" or $gid eq "");
exit error ("u: $gid: groupname not found in system") unless (match_name("$root/etc/group", "$gid"));
}
#UID
if ($id eq "-") { $id="";
}
else {
exit error ("u: $id: numeric (u)id expected") unless (is_number($id));
if (match_uid("$root/etc/passwd", "$id")) {$id="";} #fallback to auto allocation for UID
}
if ($id eq "") { #auto alloc of (u)id; at this point gid is expected to be valid
$lrange="-g $gid"; #useradd: -g gid can be number or groupname
}
else {
$lrange="-u $id -g $gid";
}
}
elsif (is_path($fields[2])) { #/path/to/file or dir
$id = (stat("$root/$fields[2]"))[4]; #NOTE: [4] = uid, [5]= gid, use gid for g lines
$gid = (stat("$root/$fields[2]"))[5];
if ( not defined $id and not defined $gid ) {#A #stat failed, path not found, fallback to autoallocation
$id=""; $gid=""; $lrange="$range"; $usergroup = 0;
}
elsif ( defined $id and defined $gid ) {
#if GID does not exists, create it
if (match_uid("$root/etc/passwd", "$id")) {$upath="1";}
if (match_uid("$root/etc/group", "$gid")) {$gpath="1";
#we need this only for supplementary group in useradd; '-G $groupname'; see WARN below
#open (my $F, '<', "$root/etc/group") or die "failed to open $root/etc/group: $!";
#while (my $fline = <$F>) { #TODO: set groupname in match_uid with a third param
# if ($fline =~ /^((.*)):(.*):\Q$gid\E:(.*)$/) {
# $groupname=$1;
# print "groupname is $groupname\n";#debug
# last;
# }
#}
#close $F;
}
if ($upath eq "1" and $gpath eq "1") { #D: UID and GID found in system: fallback to autoallocation
#WARNING should we use '-G $groupname'=supplgroup in useradd before setting gid=""? gid should be the groupname
# so that the user can access the path?? NOTE: systemd (v257) does not do that
$id=""; $gid=""; $lrange="$range"; $usergroup = 0;
}
elsif ($upath eq "0" and $gpath eq "0") { #E: UID and GID not found in system
$usergroup = 1; $groupname=$name; $groupid="-g $gid"; $lrange="-u $id -g $gid"; #TODO RM groupid
}
elsif ($upath eq "1" and $gpath eq "0") { #B: UID found, GID not found
$usergroup = 1; $groupname=$name; $groupid="-g $gid"; #TODO RM groupid
if (match_uid("$root/etc/passwd", "$gid")) {#B2#UID=GID already taken, fallback to auto for uid
$lrange="-g $gid";
}
else { #B1#UID=GID free, use GID for both
$lrange="-u $gid -g $gid";
}
}
else {#$upath="0", $gpath="1"; #C: UID not found, GID found
#WARNING should we use '-G $groupname'=supplgroup in useradd before setting gid=""? gid should be the groupname
# so that the user can access the path?? NOTE: systemd (v257) does not do that
$gid=""; $usergroup = 0; $lrange="-u $id";
}
}
else {#error, problem with stat?, should not happen;
exit error ("u: path $id: unexpected behavior of stat()")
}
}
else {exit error ("u: $fields[2]: invalid id field value ");}
}
else {#not defined = auto allocation
$id=""; $gid=""; $lrange="$range"; $usergroup = 0;
}
if (is_reserved($id)) { exit error ("invalid id: $id: 65535 and 4294967295 are reserved")}
if (is_reserved($gid)) { exit error ("invalid id: $gid: 65535 and 4294967295 are reserved")}
#GECOS, home, shell
if (not defined $fields[3]) {$gecos = "";}# default home and shell are fine
elsif ($fields[3] eq "-" ) {$gecos = "";
set_home_shell($fields[4], $fields[5]);
}
elsif ($fields[3] =~ /^"(.*)"$/) {
$gecos = $fields[3]; #$gecos =$1;
set_home_shell($fields[4], $fields[5]);
}
else {# handle U and GECOS field, string quoted with spaces
my @gfields = split "\"" , $uline; $gecos ="\"$gfields[1]\""; #$gecos ="$gfields[1]";
if (defined $gfields[2]) {
my @aftergf = split " ", $gfields[2];
set_home_shell($aftergf[0], $aftergf[1]);
}
}
if ($debug) {print "name: $name\n"; print "id: $id\n"; print "gid: $gid\n";}#debug
if ($debug) {print "gecos: $gecos \n"; print"home: $home\n"; print"shell: $shell\n";}#debug
if ($debug) {print "COMMAND(S) are: \n";}#debug
if ($usergroup) { #create group (gid)
if ($debug) {print "groupadd $prefix -r -g$gid $groupname\n";}
system('groupadd', "$prefix", '-r', "-g$gid", "$groupname");
if ($id ne "") { #uid + gid
if ($debug) {print "useradd $prefix -r -u$id -g$gid -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-u$id", "-g$gid" , "-d$home", "-s$shell", "$name");
}
else { #gid only
if ($debug) {print "useradd $prefix -r -g$gid -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-g$gid", "-d$home", "-s$shell", "$name");
}
}
elsif ($id ne "") { #group=auto; uid
if ($debug) {print "useradd $prefix -r -u$id -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-u$id", "-d$home", "-s$shell", "$name");
}
elsif ($rcounter) { #group=auto; range
if ($debug) {print "useradd $prefix -r -KSYS_UID_MIN=$rmins[0] -KSYS_UID_MAX=$rmaxs[0] -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-KSYS_UID_MIN=$rmins[0]", "-KSYS_UID_MAX=$rmaxs[0]", "-d$home", "-s$shell", "$name");
}
else { #group=auto; no range, no uid
if ($debug) {print "useradd $prefix -r -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-d$home", "-s$shell", "$name");
}
if ($gecos ne "") {
if ($debug) {print "usermod -c$gecos $name\n";}
system('usermod', "-c$gecos", "$name");
}
if ($fields[0] eq "u!") {
if ($debug) {print "usermod $prefix -L $name\n";}
system('usermod', "$prefix", '-L', "$name");
}
$name =""; $id=""; $gid=""; $gecos=""; $home='/'; $shell='/sbin/nologin'; $lrange=""; #@fields = ();
$upath="0"; $gpath="0"; $usergroup = 0; $groupname="";
if ($debug) {print "\n"; print "\n";}#debug
}
}
if (@mlines) {
for (@mlines) {
my $mline = $_; my @fields = split " " , $mline;
if ($debug) {print "line is: $mline\n";}#debug
$name = $fields[1]; if ($name eq "" || $name eq "-") { exit error ("m type: missing or invalid name field");}
if ($fields[2] eq "" || $fields[2] eq "-") { exit error ("m: $fields[2]: missing or invalid id field");}
elsif (is_number($fields[2]) ) {exit error ("m: $fields[2]: group name expected for id field");}
elsif (is_path($fields[2]) ) {exit error ("m: $fields[2]: group name expected for id field");}
elsif ($fields[2] =~ /^(.*):(.*)$/) {exit error ("m: $fields[2]: group name expected for id field");}
else {$id=$fields[2]}
if ($debug) {print "name: $name\n"; print "id: $id\n";}#debug
if ($debug) {print "COMMANDS are: \n";}#debug
unless (match_name("$root/etc/group", "$id")) { #create group if is not found
if ($rcounter) {
if ($debug) {print "groupadd $prefix -r -KSYS_GID_MIN=$rmins[0] -KSYS_GID_MAX=$rmaxs[0] $id\n";}
system('groupadd', "$prefix", '-r', "-KSYS_GID_MIN=$rmins[0]", "-KSYS_GID_MAX=$rmaxs[0]", "$id");
}
else {
if ($debug) {print "groupadd $prefix -r $id\n";}
system('groupadd', "$prefix", '-r', "$id");
}
}
unless (match_name("$root/etc/passwd", "$name")) {#now we are sure group exists, so create user if is not found
if ($rcounter) {
if ($debug) {print "useradd $prefix -r -KSYS_UID_MIN=$rmins[0] -KSYS_UID_MAX=$rmaxs[0] -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-KSYS_UID_MIN=$rmins[0]", "-KSYS_UID_MAX=$rmaxs[0]", "-d$home", "-s$shell", "$name");
}
else {
if ($debug) {print "useradd $prefix -r -d$home -s$shell $name\n";}
system('useradd', "$prefix", '-r', "-d$home", "-s$shell", "$name");
}
}
if ($debug) {print "usermod $prefix -a -G$id $name\n";}#NOTE: g lines adds as supplementary -g=primary// -G=supplementary
system('usermod', "$prefix", '-a', "-G$id", "$name");
$name =""; $id=""; $gid="";#@fields = ();
if ($debug) {print "\n"; print "\n";}#debug
}
}
}
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