tvl-depot/scripts/nix-push.in
Eelco Dolstra 2d35116c13 * Setuid support for sharing a Nix installation between multiple
users.

  If the configure flag `--enable-setuid' is used, the Nix programs
  nix-env, nix-store, etc. are installed with the setuid bit turned on
  so that they are executed as the user and group specified by
  `--with-nix-user=USER' and `--with-nix-group=GROUP', respectively
  (with defaults `nix' and `nix').

  The setuid programs drop all special privileges if they are executed
  by a user who is not a member of the Nix group.

  The setuid feature is a quick hack to enable sharing of a Nix
  installation between users who trust each other.  It is not
  generally secure, since any user in the Nix group can modify (by
  building an appropriate derivation) any object in the store, and for
  instance inject trojans into binaries used by other users.

  The setuid programs are owned by root, not the Nix user.  This is
  because on Unix normal users cannot change the real uid, only the
  effective uid.  Many programs don't work properly when the real uid
  differs from the effective uid.  For instance, Perl will turn on
  taint mode.  However, the setuid programs drop all root privileges
  immediately, changing all uids and gids to the Nix user and group.
2004-08-20 14:49:05 +00:00

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#! @perl@ -w
use strict;
use POSIX qw(tmpnam);
my $tmpdir;
do { $tmpdir = tmpnam(); }
until mkdir $tmpdir, 0777;
my $nixfile = "$tmpdir/create-nars.nix";
my $manifest = "$tmpdir/MANIFEST";
END { unlink $manifest; unlink $nixfile; rmdir $tmpdir; }
my $curl = "@curl@ --fail --silent";
my $extraCurlFlags = ${ENV{'CURL_FLAGS'}};
$curl = "$curl $extraCurlFlags" if defined $extraCurlFlags;
# Parse the command line.
my $archives_put_url = shift @ARGV;
my $archives_get_url = shift @ARGV;
my $manifest_put_url = shift @ARGV;
# From the given store expressions, determine the requisite store
# paths.
my %storepaths;
foreach my $storeexpr (@ARGV) {
die unless $storeexpr =~ /^\//;
# Get all paths referenced by the normalisation of the given
# Nix expression.
system "@bindir@/nix-store --realise $storeexpr > /dev/null";
die if ($?);
open PATHS, "@bindir@/nix-store --query --requisites --include-successors $storeexpr 2> /dev/null |" or die;
while (<PATHS>) {
chomp;
die "bad: $_" unless /^\//;
$storepaths{$_} = "";
}
close PATHS;
}
my @storepaths = keys %storepaths;
# For each path, create a Nix expression that turns the path into
# a Nix archive.
open NIX, ">$nixfile";
print NIX "[";
foreach my $storepath (@storepaths) {
die unless ($storepath =~ /\/[0-9a-z]{32}.*$/);
# Construct a Nix expression that creates a Nix archive.
my $nixexpr =
"((import @datadir@/nix/corepkgs/nar/nar.nix) " .
# !!! $storepath should be represented as a closure
"{path = \"$storepath\"; system = \"@system@\";}) ";
print NIX $nixexpr;
}
print NIX "]";
close NIX;
# Instantiate store expressions from the Nix expression.
my @storeexprs;
print STDERR "instantiating store expressions...\n";
open STOREEXPRS, "@bindir@/nix-instantiate $nixfile |" or die "cannot run nix-instantiate";
while (<STOREEXPRS>) {
chomp;
die unless /^\//;
push @storeexprs, $_;
}
close STOREEXPRS;
# Realise the store expressions.
print STDERR "creating archives...\n";
my @narpaths;
my @tmp = @storeexprs;
while (scalar @tmp > 0) {
my $n = scalar @tmp;
if ($n > 256) { $n = 256 };
my @tmp2 = @tmp[0..$n - 1];
@tmp = @tmp[$n..scalar @tmp - 1];
system "@bindir@/nix-store --realise @tmp2 > /dev/null";
if ($?) { die "`nix-store --realise' failed"; }
open NARPATHS, "@bindir@/nix-store --query --list @tmp2 |" or die "cannot run nix";
while (<NARPATHS>) {
chomp;
die unless (/^\//);
push @narpaths, "$_";
}
close NARPATHS;
}
# Create the manifest.
print STDERR "creating manifest...\n";
open MANIFEST, ">$manifest";
my @nararchives;
for (my $n = 0; $n < scalar @storepaths; $n++) {
my $storepath = $storepaths[$n];
my $nardir = $narpaths[$n];
$storepath =~ /\/([^\/]*)$/;
my $basename = $1;
defined $basename or die;
my $narname = "$basename.nar.bz2";
my $narfile = "$nardir/$narname";
(-f $narfile) or die "narfile for $storepath not found";
push @nararchives, $narfile;
open MD5, "$nardir/md5" or die "cannot open hash";
my $hash = <MD5>;
chomp $hash;
$hash =~ /^[0-9a-z]{32}$/ or die "invalid hash";
close MD5;
print MANIFEST "{\n";
print MANIFEST " StorePath: $storepath\n";
print MANIFEST " NarURL: $archives_get_url/$narname\n";
print MANIFEST " MD5: $hash\n";
if ($storepath =~ /\.store$/) {
open PREDS, "@bindir@/nix-store --query --predecessors $storepath |" or die "cannot run nix";
while (<PREDS>) {
chomp;
die unless (/^\//);
my $pred = $_;
# Only include predecessors that are themselves being
# pushed.
if (defined $storepaths{$pred}) {
print MANIFEST " SuccOf: $pred\n";
}
}
close PREDS;
}
print MANIFEST "}\n";
}
close MANIFEST;
# Upload the archives.
print STDERR "uploading archives...\n";
foreach my $nararchive (@nararchives) {
$nararchive =~ /\/([^\/]*)$/;
my $basename = $1;
if (system("$curl --head $archives_get_url/$basename > /dev/null") != 0) {
print STDERR " $nararchive\n";
system("$curl --show-error --upload-file " .
"'$nararchive' '$archives_put_url/$basename' > /dev/null") == 0 or
die "curl failed on $nararchive: $?";
}
}
# Upload the manifest.
print STDERR "uploading manifest...\n";
system("$curl --show-error --upload-file " .
"'$manifest' '$manifest_put_url' > /dev/null") == 0 or
die "curl failed on $manifest: $?";