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executable file 144 lines (126 sloc) 3.57 KB
#!/usr/bin/perl
use strict;
use IO::File;
use POSIX qw(ENOENT ENOSYS EEXIST EPERM O_RDONLY O_RDWR O_APPEND O_CREAT);
use Fcntl qw(S_ISBLK S_ISCHR S_ISFIFO SEEK_SET);
use Data::Dumper;
require 'syscall.ph'; # for SYS_mknod and SYS_lchown
my ($rootdir) = @ARGV;
# strip leading and trailing slashes
$rootdir = $1 if($rootdir =~ /^\/?(.*)\/?$/);
sub fixup { return "/$rootdir" . shift }
sub x_getattr {
my ($file) = fixup(shift);
my (@list) = lstat($file);
return -$! unless @list;
return @list;
}
sub x_getdir {
my ($dirname) = fixup(shift);
unless(opendir(DIRHANDLE,$dirname)) {
return -ENOENT();
}
my (@files) = readdir(DIRHANDLE);
closedir(DIRHANDLE);
return (@files, 0);
}
sub x_open {
my ($file) = fixup(shift);
my ($mode) = shift;
return -$! unless sysopen(FILE,$file,$mode);
close(FILE);
return 0;
}
sub x_read {
my ($file,$bufsize,$off) = @_;
my ($rv) = -ENOSYS();
my ($handle) = new IO::File;
return -ENOENT() unless -e ($file = fixup($file));
my ($fsize) = -s $file;
return -ENOSYS() unless open($handle,$file);
if(seek($handle,$off,SEEK_SET)) {
read($handle,$rv,$bufsize);
}
return $rv;
}
sub x_write {
my ($file,$buf,$off) = @_;
my ($rv);
return -ENOENT() unless -e ($file = fixup($file));
my ($fsize) = -s $file;
return -ENOSYS() unless open(FILE,'+<',$file);
if($rv = seek(FILE,$off,SEEK_SET)) {
$rv = print(FILE $buf);
}
$rv = -ENOSYS() unless $rv;
close(FILE);
return length($buf);
}
sub err { return (-shift || -$!) }
sub x_readlink { return readlink(fixup(shift) ); }
sub x_unlink { return unlink(fixup(shift)) ? 0 : -$!; }
sub x_rmdir { return err(rmdir(fixup(shift)) ); }
sub x_symlink { print "symlink\n"; return symlink(shift,fixup(shift)) ? 0 : -$!; }
sub x_rename {
my ($old) = fixup(shift);
my ($new) = fixup(shift);
my ($err) = rename($old,$new) ? 0 : -ENOENT();
return $err;
}
sub x_link { return link(fixup(shift),fixup(shift)) ? 0 : -$! }
sub x_chown {
my ($fn) = fixup(shift);
print "nonexistent $fn\n" unless -e $fn;
my ($uid,$gid) = @_;
# perl's chown() does not chown symlinks, it chowns the symlink's
# target. it fails when the link's target doesn't exist, because
# the stat64() syscall fails.
# this causes error messages when unpacking symlinks in tarballs.
my ($err) = syscall(&SYS_lchown,$fn,$uid,$gid,$fn) ? -$! : 0;
return $err;
}
sub x_chmod {
my ($fn) = fixup(shift);
my ($mode) = shift;
my ($err) = chmod($mode,$fn) ? 0 : -$!;
return $err;
}
sub x_truncate { return truncate(fixup(shift),shift) ? 0 : -$! ; }
sub x_utime { return utime($_[1],$_[2],fixup($_[0])) ? 0:-$!; }
sub x_mkdir { my ($name, $perm) = @_; return 0 if mkdir(fixup($name),$perm); return -$!; }
sub x_rmdir { return 0 if rmdir fixup(shift); return -$!; }
sub x_mknod {
# since this is called for ALL files, not just devices, I'll do some checks
# and possibly run the real mknod command.
my ($file, $modes, $dev) = @_;
$file = fixup($file);
$! = 0;
syscall(&SYS_mknod,$file,$modes,$dev);
return -$!;
}
# kludge
sub x_statfs {return 255,1000000,500000,1000000,500000,4096}
$| = 1;
my ($len);
while(read(STDIN,$len,9) == 9) {
chomp $len;
my ($data,$VAR1,@args);
eval {
$SIG{ALRM} = sub { die "timeout\n"};
$data = "";
alarm 5;
read(STDIN,$data,$len-length($data),length($data))
while(length($data) < $len);
alarm 0;
};
die $@ if $@;
eval $data;
@args = @{$VAR1};
my $cmd = shift(@args);
exit 0 if $cmd eq "bye";
die "cannot find command $cmd\n" unless exists($main::{"x_$cmd"});
@args = $main::{"x_$cmd"}(@args);
$cmd = Dumper(\@args)."\n";
$cmd = sprintf("%08i\n%s",length($cmd),$cmd);
print $cmd;
}