nixpkgs/pkgs/build-support/buildenv/builder.pl
2021-08-20 15:47:47 +03:00

284 lines
8.3 KiB
Perl
Executable File

#! @perl@ -w
use strict;
use Cwd 'abs_path';
use IO::Handle;
use File::Path;
use File::Basename;
use File::Compare;
use JSON::PP;
STDOUT->autoflush(1);
$SIG{__WARN__} = sub { warn "warning: ", @_ };
$SIG{__DIE__} = sub { die "error: ", @_ };
my $out = $ENV{"out"};
my $extraPrefix = $ENV{"extraPrefix"};
my @pathsToLink = split ' ', $ENV{"pathsToLink"};
sub isInPathsToLink {
my $path = shift;
$path = "/" if $path eq "";
foreach my $elem (@pathsToLink) {
return 1 if
$elem eq "/" ||
(substr($path, 0, length($elem)) eq $elem
&& (($path eq $elem) || (substr($path, length($elem), 1) eq "/")));
}
return 0;
}
# Returns whether a path in one of the linked packages may contain
# files in one of the elements of pathsToLink.
sub hasPathsToLink {
my $path = shift;
foreach my $elem (@pathsToLink) {
return 1 if
$path eq "" ||
(substr($elem, 0, length($path)) eq $path
&& (($path eq $elem) || (substr($elem, length($path), 1) eq "/")));
}
return 0;
}
# Similar to `lib.isStorePath`
sub isStorePath {
my $path = shift;
my $storePath = "@storeDir@";
return substr($path, 0, 1) eq "/" && dirname($path) eq $storePath;
}
# For each activated package, determine what symlinks to create.
my %symlinks;
# Add all pathsToLink and all parent directories.
#
# For "/a/b/c" that will include
# [ "", "/a", "/a/b", "/a/b/c" ]
#
# That ensures the whole directory tree needed by pathsToLink is
# created as directories and not symlinks.
$symlinks{""} = ["", 0];
for my $p (@pathsToLink) {
my @parts = split '/', $p;
my $cur = "";
for my $x (@parts) {
$cur = $cur . "/$x";
$cur = "" if $cur eq "/";
$symlinks{$cur} = ["", 0];
}
}
sub findFiles;
sub findFilesInDir {
my ($relName, $target, $ignoreCollisions, $checkCollisionContents, $priority) = @_;
opendir DIR, "$target" or die "cannot open `$target': $!";
my @names = readdir DIR or die;
closedir DIR;
foreach my $name (@names) {
next if $name eq "." || $name eq "..";
findFiles("$relName/$name", "$target/$name", $name, $ignoreCollisions, $checkCollisionContents, $priority);
}
}
sub checkCollision {
my ($path1, $path2) = @_;
if (! -e $path1 || ! -e $path2) {
return 0;
}
my $stat1 = (stat($path1))[2];
my $stat2 = (stat($path2))[2];
if ($stat1 != $stat2) {
warn "different permissions in `$path1' and `$path2': "
. sprintf("%04o", $stat1 & 07777) . " <-> "
. sprintf("%04o", $stat2 & 07777);
return 0;
}
return compare($path1, $path2) == 0;
}
sub prependDangling {
my $path = shift;
return (-l $path && ! -e $path ? "dangling symlink " : "") . "`$path'";
}
sub findFiles {
my ($relName, $target, $baseName, $ignoreCollisions, $checkCollisionContents, $priority) = @_;
# The store path must not be a file
if (-f $target && isStorePath $target) {
die "The store path $target is a file and can't be merged into an environment using pkgs.buildEnv!";
}
# Urgh, hacky...
return if
$relName eq "/propagated-build-inputs" ||
$relName eq "/nix-support" ||
$relName =~ /info\/dir/ ||
( $relName =~ /^\/share\/mime\// && !( $relName =~ /^\/share\/mime\/packages/ ) ) ||
$baseName eq "perllocal.pod" ||
$baseName eq "log" ||
! (hasPathsToLink($relName) || isInPathsToLink($relName));
my ($oldTarget, $oldPriority) = @{$symlinks{$relName} // [undef, undef]};
# If target doesn't exist, create it. If it already exists as a
# symlink to a file (not a directory) in a lower-priority package,
# overwrite it.
if (!defined $oldTarget || ($priority < $oldPriority && ($oldTarget ne "" && ! -d $oldTarget))) {
# If target is a dangling symlink, emit a warning.
if (-l $target && ! -e $target) {
my $link = readlink $target;
warn "creating dangling symlink `$out$extraPrefix/$relName' -> `$target' -> `$link'\n";
}
$symlinks{$relName} = [$target, $priority];
return;
}
# If target already exists and both targets resolves to the same path, skip
if (
defined $oldTarget && $oldTarget ne "" &&
defined abs_path($target) && defined abs_path($oldTarget) &&
abs_path($target) eq abs_path($oldTarget)
) {
# Prefer the target that is not a symlink, if any
if (-l $oldTarget && ! -l $target) {
$symlinks{$relName} = [$target, $priority];
}
return;
}
# If target already exists as a symlink to a file (not a
# directory) in a higher-priority package, skip.
if (defined $oldTarget && $priority > $oldPriority && $oldTarget ne "" && ! -d $oldTarget) {
return;
}
# If target is supposed to be a directory but it isn't, die with an error message
# instead of attempting to recurse into it, only to fail then.
# This happens e.g. when pathsToLink contains a non-directory path.
if ($oldTarget eq "" && ! -d $target) {
die "not a directory: `$target'\n";
}
unless (-d $target && ($oldTarget eq "" || -d $oldTarget)) {
# Prepend "dangling symlink" to paths if applicable.
my $targetRef = prependDangling($target);
my $oldTargetRef = prependDangling($oldTarget);
if ($ignoreCollisions) {
warn "collision between $targetRef and $oldTargetRef\n" if $ignoreCollisions == 1;
return;
} elsif ($checkCollisionContents && checkCollision($oldTarget, $target)) {
return;
} else {
die "collision between $targetRef and $oldTargetRef\n";
}
}
findFilesInDir($relName, $oldTarget, $ignoreCollisions, $checkCollisionContents, $oldPriority) unless $oldTarget eq "";
findFilesInDir($relName, $target, $ignoreCollisions, $checkCollisionContents, $priority);
$symlinks{$relName} = ["", $priority]; # denotes directory
}
my %done;
my %postponed;
sub addPkg {
my ($pkgDir, $ignoreCollisions, $checkCollisionContents, $priority) = @_;
return if (defined $done{$pkgDir});
$done{$pkgDir} = 1;
findFiles("", $pkgDir, "", $ignoreCollisions, $checkCollisionContents, $priority);
my $propagatedFN = "$pkgDir/nix-support/propagated-user-env-packages";
if (-e $propagatedFN) {
open PROP, "<$propagatedFN" or die;
my $propagated = <PROP>;
close PROP;
my @propagated = split ' ', $propagated;
foreach my $p (@propagated) {
$postponed{$p} = 1 unless defined $done{$p};
}
}
}
# Read packages list.
my $pkgs;
if (exists $ENV{"pkgsPath"}) {
open FILE, $ENV{"pkgsPath"};
$pkgs = <FILE>;
close FILE;
} else {
$pkgs = $ENV{"pkgs"}
}
# Symlink to the packages that have been installed explicitly by the
# user.
for my $pkg (@{decode_json $pkgs}) {
for my $path (@{$pkg->{paths}}) {
addPkg($path,
$ENV{"ignoreCollisions"} eq "1",
$ENV{"checkCollisionContents"} eq "1",
$pkg->{priority})
if -e $path;
}
}
# Symlink to the packages that have been "propagated" by packages
# installed by the user (i.e., package X declares that it wants Y
# installed as well). We do these later because they have a lower
# priority in case of collisions.
my $priorityCounter = 1000; # don't care about collisions
while (scalar(keys %postponed) > 0) {
my @pkgDirs = keys %postponed;
%postponed = ();
foreach my $pkgDir (sort @pkgDirs) {
addPkg($pkgDir, 2, $ENV{"checkCollisionContents"} eq "1", $priorityCounter++);
}
}
# Create the symlinks.
my $nrLinks = 0;
foreach my $relName (sort keys %symlinks) {
my ($target, $priority) = @{$symlinks{$relName}};
my $abs = "$out" . "$extraPrefix" . "/$relName";
next unless isInPathsToLink $relName;
if ($target eq "") {
#print "creating directory $relName\n";
mkpath $abs or die "cannot create directory `$abs': $!";
} else {
#print "creating symlink $relName to $target\n";
symlink $target, $abs ||
die "error creating link `$abs': $!";
$nrLinks++;
}
}
print STDERR "created $nrLinks symlinks in user environment\n";
my $manifest = $ENV{"manifest"};
if ($manifest) {
symlink($manifest, "$out/manifest") or die "cannot create manifest";
}