* Make nix-env --dry-run print the paths to be substituted correctly

again.  (After the previous substituter mechanism refactoring I
  didn't update the code that obtains the references of substitutable
  paths.)  This required some refactoring: the substituter programs
  are now kept running and receive/respond to info requests via
  stdin/stdout.
This commit is contained in:
Eelco Dolstra 2008-08-02 12:54:35 +00:00
parent fc691e1cbd
commit 3c92ea399d
14 changed files with 338 additions and 272 deletions

View file

@ -2,6 +2,9 @@
use strict;
use File::Basename;
use IO::Handle;
STDOUT->autoflush(1);
my @remoteStoresAll = split ':', ($ENV{"NIX_OTHER_STORES"} or "");
@ -33,42 +36,46 @@ sub findStorePath {
}
if ($ARGV[0] eq "--query-paths") {
foreach my $store (@remoteStores) {
opendir DIR, "$store/var/nix/db/info" or next;
print "@storedir@/$_\n" foreach readdir DIR;
closedir DIR;
}
}
if ($ARGV[0] eq "--query") {
while (<STDIN>) {
my $cmd = $_; chomp $cmd;
elsif ($ARGV[0] eq "--query-info") {
shift @ARGV;
foreach my $storePath (@ARGV) {
(my $infoFile) = findStorePath $storePath;
next unless $infoFile;
my $deriver = "";
my @references = ();
open INFO, "<$infoFile" or die "cannot read info file $infoFile\n";
while (<INFO>) {
chomp;
#print STDERR "GOT $_\n";
/^([\w-]+): (.*)$/ or die "bad info file";
my $key = $1;
my $value = $2;
if ($key eq "Deriver") { $deriver = $value; }
elsif ($key eq "References") { @references = split ' ', $value; }
if ($cmd eq "have") {
my $storePath = <STDIN>; chomp $storePath;
(my $infoFile) = findStorePath $storePath;
print STDOUT ($infoFile ? "1\n" : "0\n");
}
close INFO;
print "$storePath\n";
print "$deriver\n";
print scalar @references, "\n";
print "$_\n" foreach @references;
elsif ($cmd eq "info") {
my $storePath = <STDIN>; chomp $storePath;
(my $infoFile) = findStorePath $storePath;
if (!$infoFile) {
print "0\n";
next; # not an error
}
print "1\n";
my $deriver = "";
my @references = ();
open INFO, "<$infoFile" or die "cannot read info file $infoFile\n";
while (<INFO>) {
chomp;
/^([\w-]+): (.*)$/ or die "bad info file";
my $key = $1;
my $value = $2;
if ($key eq "Deriver") { $deriver = $value; }
elsif ($key eq "References") { @references = split ' ', $value; }
}
close INFO;
print "$deriver\n";
print scalar @references, "\n";
print "$_\n" foreach @references;
}
else { die "unknown command `$cmd'"; }
}
}

View file

@ -5,27 +5,18 @@ use readmanifest;
use POSIX qw(strftime);
use File::Temp qw(tempdir);
STDOUT->autoflush(1);
my $manifestDir = "@localstatedir@/nix/manifests";
my $logFile = "@localstatedir@/log/nix/downloads";
# Create a temporary directory.
my $tmpDir = tempdir("nix-download.XXXXXX", CLEANUP => 1, TMPDIR => 1)
or die "cannot create a temporary directory";
chdir $tmpDir or die "cannot change to `$tmpDir': $!";
my $tmpNar = "$tmpDir/nar";
my $tmpNar2 = "$tmpDir/nar2";
# Load all manifests.
my %narFiles;
my %localPaths;
my %patches;
for my $manifest (glob "$manifestDir/*.nixmanifest") {
# print STDERR "reading $manifest\n";
if (readManifest($manifest, \%narFiles, \%localPaths, \%patches) < 3) {
print STDERR "you have an old-style manifest `$manifest'; please delete it\n";
exit 1;
@ -35,34 +26,40 @@ for my $manifest (glob "$manifestDir/*.nixmanifest") {
# Parse the arguments.
if ($ARGV[0] eq "--query-paths") {
foreach my $storePath (keys %narFiles) { print "$storePath\n"; }
foreach my $storePath (keys %localPaths) { print "$storePath\n"; }
exit 0;
}
if ($ARGV[0] eq "--query") {
elsif ($ARGV[0] eq "--query-info") {
shift @ARGV;
foreach my $storePath (@ARGV) {
my $info;
if (defined $narFiles{$storePath}) {
$info = @{$narFiles{$storePath}}[0];
while (<STDIN>) {
my $cmd = $_; chomp $cmd;
if ($cmd eq "have") {
my $storePath = <STDIN>; chomp $storePath;
print STDOUT ((defined $narFiles{$storePath} or defined $localPaths{$storePath})
? "1\n" : "0\n");
}
elsif (defined $localPaths{$storePath}) {
$info = @{$localPaths{$storePath}}[0];
}
else {
next; # not an error
}
print "$storePath\n";
print "$info->{deriver}\n";
my @references = split " ", $info->{references};
my $count = scalar @references;
print "$count\n";
foreach my $reference (@references) {
print "$reference\n";
elsif ($cmd eq "info") {
my $storePath = <STDIN>; chomp $storePath;
my $info;
if (defined $narFiles{$storePath}) {
$info = @{$narFiles{$storePath}}[0];
}
elsif (defined $localPaths{$storePath}) {
$info = @{$localPaths{$storePath}}[0];
}
else {
print "0\n";
next; # not an error
}
print "1\n";
print "$info->{deriver}\n";
my @references = split " ", $info->{references};
print scalar @references, "\n";
print "$_\n" foreach @references;
}
else { die "unknown command `$cmd'"; }
}
exit 0;
}
@ -75,6 +72,16 @@ die unless scalar @ARGV == 2;
my $targetPath = $ARGV[1];
# Create a temporary directory.
my $tmpDir = tempdir("nix-download.XXXXXX", CLEANUP => 1, TMPDIR => 1)
or die "cannot create a temporary directory";
chdir $tmpDir or die "cannot change to `$tmpDir': $!";
my $tmpNar = "$tmpDir/nar";
my $tmpNar2 = "$tmpDir/nar2";
open LOGFILE, ">>$logFile" or die "cannot open log file $logFile";
my $date = strftime ("%F %H:%M:%S UTC", gmtime (time));

View file

@ -184,11 +184,6 @@ private:
/* Goals waiting for a build slot. */
WeakGoals wantingToBuild;
/* Goals waiting for info from substituters (using --query-info),
and the info they're (collectively) waiting for. */
WeakGoals waitingForInfo;
map<Path, PathSet> requestedInfo;
/* Child processes currently running. */
Children children;
@ -243,11 +238,6 @@ public:
call is made to childTerminate(..., true). */
void waitForChildTermination(GoalPtr goal);
/* Put `goal' to sleep until the top-level loop has run `sub' to
get info about `storePath' (with --query-info). We combine
substituter invocations to reduce overhead. */
void waitForInfo(GoalPtr goal, Path sub, Path storePath);
/* Wait for any goal to finish. Pretty indiscriminate way to
wait for some resource that some other goal is holding. */
void waitForAnyGoal(GoalPtr goal);
@ -258,12 +248,6 @@ public:
/* Wait for input to become available. */
void waitForInput();
private:
/* Process the pending paths in requestedInfo and wake up the
goals in waitingForInfo. */
void getInfo();
};
@ -2042,12 +2026,12 @@ void DerivationGoal::initChild()
}
/* Close all other file descriptors. */
int maxFD = 0;
maxFD = sysconf(_SC_OPEN_MAX);
for (int fd = 0; fd < maxFD; ++fd)
if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO
&& (!inHook || (fd != 3 && fd != 4)))
close(fd); /* ignore result */
set<int> exceptions;
if (inHook) {
exceptions.insert(3);
exceptions.insert(4);
}
closeMostFDs(exceptions);
}
@ -2118,10 +2102,8 @@ private:
/* The current substituter. */
Path sub;
/* Path info returned by the substituter's --query-info operation. */
bool infoOkay;
PathSet references;
Path deriver;
/* Path info returned by the substituter's query info operation. */
SubstitutablePathInfo info;
/* Pipe for the substitute's standard output/error. */
Pipe logPipe;
@ -2205,6 +2187,42 @@ void SubstitutionGoal::init()
return;
}
if (!worker.store.querySubstitutablePathInfo(storePath, info)) {
printMsg(lvlError,
format("path `%1%' is required, but there is no substituter that knows anything about it")
% storePath);
amDone(ecFailed);
return;
}
/* To maintain the closure invariant, we first have to realise the
paths referenced by this one. */
foreach (PathSet::iterator, i, info.references)
if (*i != storePath) /* ignore self-references */
addWaitee(worker.makeSubstitutionGoal(*i));
if (waitees.empty()) /* to prevent hang (no wake-up event) */
referencesValid();
else
state = &SubstitutionGoal::referencesValid;
}
void SubstitutionGoal::referencesValid()
{
trace("all references realised");
if (nrFailed > 0) {
printMsg(lvlError,
format("some references of path `%1%' could not be realised") % storePath);
amDone(ecFailed);
return;
}
foreach (PathSet::iterator, i, info.references)
if (*i != storePath) /* ignore self-references */
assert(worker.store.isValidPath(*i));
subs = substituters;
tryNext();
@ -2228,51 +2246,6 @@ void SubstitutionGoal::tryNext()
sub = subs.front();
subs.pop_front();
infoOkay = false;
state = &SubstitutionGoal::gotInfo;
worker.waitForInfo(shared_from_this(), sub, storePath);
}
void SubstitutionGoal::gotInfo()
{
trace("got info");
if (!infoOkay) {
tryNext();
return;
}
/* To maintain the closure invariant, we first have to realise the
paths referenced by this one. */
for (PathSet::iterator i = references.begin();
i != references.end(); ++i)
if (*i != storePath) /* ignore self-references */
addWaitee(worker.makeSubstitutionGoal(*i));
if (waitees.empty()) /* to prevent hang (no wake-up event) */
referencesValid();
else
state = &SubstitutionGoal::referencesValid;
}
void SubstitutionGoal::referencesValid()
{
trace("all references realised");
if (nrFailed > 0) {
printMsg(lvlError,
format("some references of path `%1%' could not be realised") % storePath);
amDone(ecFailed);
return;
}
for (PathSet::iterator i = references.begin();
i != references.end(); ++i)
if (*i != storePath) /* ignore self-references */
assert(worker.store.isValidPath(*i));
state = &SubstitutionGoal::tryToRun;
worker.waitForBuildSlot(shared_from_this());
}
@ -2413,7 +2386,7 @@ void SubstitutionGoal::finished()
Hash contentHash = hashPath(htSHA256, storePath);
worker.store.registerValidPath(storePath, contentHash,
references, deriver);
info.references, info.deriver);
outputLock->setDeletion(true);
@ -2608,14 +2581,6 @@ void Worker::waitForChildTermination(GoalPtr goal)
}
void Worker::waitForInfo(GoalPtr goal, Path sub, Path storePath)
{
debug("wait for info");
requestedInfo[sub].insert(storePath);
waitingForInfo.insert(goal);
}
void Worker::waitForAnyGoal(GoalPtr goal)
{
debug("wait for any goal");
@ -2623,68 +2588,6 @@ void Worker::waitForAnyGoal(GoalPtr goal)
}
void Worker::getInfo()
{
for (map<Path, PathSet>::iterator i = requestedInfo.begin();
i != requestedInfo.end(); ++i)
{
Path sub = i->first;
PathSet paths = i->second;
while (!paths.empty()) {
/* Run the substituter for at most 100 paths at a time to
prevent command line overflows. */
PathSet paths2;
while (!paths.empty() && paths2.size() < 100) {
paths2.insert(*paths.begin());
paths.erase(paths.begin());
}
/* Ask the substituter for the references and deriver of
the paths. */
debug(format("running `%1%' to get info about `%2%'") % sub % showPaths(paths2));
Strings args;
args.push_back("--query-info");
args.insert(args.end(), paths2.begin(), paths2.end());
string res = runProgram(sub, false, args);
std::istringstream str(res);
while (true) {
ValidPathInfo info = decodeValidPathInfo(str);
if (info.path == "") break;
/* !!! inefficient */
for (WeakGoals::iterator k = waitingForInfo.begin();
k != waitingForInfo.end(); ++k)
{
GoalPtr goal = k->lock();
if (goal) {
SubstitutionGoal * goal2 = dynamic_cast<SubstitutionGoal *>(goal.get());
if (goal2->storePath == info.path) {
goal2->references = info.references;
goal2->deriver = info.deriver;
goal2->infoOkay = true;
wakeUp(goal);
}
}
}
}
}
}
for (WeakGoals::iterator k = waitingForInfo.begin();
k != waitingForInfo.end(); ++k)
{
GoalPtr goal = k->lock();
if (goal) wakeUp(goal);
}
requestedInfo.clear();
waitingForInfo.clear(); // !!! have we done them all?
}
void Worker::run(const Goals & _topGoals)
{
for (Goals::iterator i = _topGoals.begin();
@ -2711,8 +2614,6 @@ void Worker::run(const Goals & _topGoals)
if (topGoals.empty()) break;
getInfo();
/* Wait for input. */
if (!children.empty())
waitForInput();

View file

@ -83,6 +83,13 @@ LocalStore::~LocalStore()
{
try {
flushDelayedUpdates();
foreach (RunningSubstituters::iterator, i, runningSubstituters) {
i->second.toBuf.reset();
i->second.to.reset();
i->second.pid.wait(true);
}
} catch (...) {
ignoreException();
}
@ -367,8 +374,6 @@ ValidPathInfo LocalStore::queryPathInfo(const Path & path)
std::map<Path, ValidPathInfo>::iterator lookup = pathInfoCache.find(path);
if (lookup != pathInfoCache.end()) return lookup->second;
//printMsg(lvlError, "queryPathInfo: " + path);
/* Read the info file. */
Path infoFile = infoFileFor(path);
if (!pathExists(infoFile))
@ -467,33 +472,105 @@ Path LocalStore::queryDeriver(const Path & path)
}
PathSet LocalStore::querySubstitutablePaths()
void LocalStore::startSubstituter(const Path & substituter, RunningSubstituter & run)
{
if (!substitutablePathsLoaded) {
for (Paths::iterator i = substituters.begin(); i != substituters.end(); ++i) {
debug(format("running `%1%' to find out substitutable paths") % *i);
Strings args;
args.push_back("--query-paths");
Strings ss = tokenizeString(runProgram(*i, false, args), "\n");
for (Strings::iterator j = ss.begin(); j != ss.end(); ++j) {
if (!isStorePath(*j))
throw Error(format("`%1%' returned a bad substitutable path `%2%'")
% *i % *j);
substitutablePaths.insert(*j);
}
if (run.pid != -1) return;
debug(format("starting substituter program `%1%'") % substituter);
Pipe toPipe, fromPipe;
toPipe.create();
fromPipe.create();
run.pid = fork();
switch (run.pid) {
case -1:
throw SysError("unable to fork");
case 0: /* child */
try {
fromPipe.readSide.close();
toPipe.writeSide.close();
if (dup2(toPipe.readSide, STDIN_FILENO) == -1)
throw SysError("dupping stdin");
if (dup2(fromPipe.writeSide, STDOUT_FILENO) == -1)
throw SysError("dupping stdout");
closeMostFDs(set<int>());
execl(substituter.c_str(), substituter.c_str(), "--query", NULL);
throw SysError(format("executing `%1%'") % substituter);
} catch (std::exception & e) {
std::cerr << "error: " << e.what() << std::endl;
}
substitutablePathsLoaded = true;
quickExit(1);
}
return substitutablePaths;
/* Parent. */
toPipe.readSide.close();
fromPipe.writeSide.close();
run.toBuf = boost::shared_ptr<stdio_filebuf>(new stdio_filebuf(toPipe.writeSide.borrow(), std::ios_base::out));
run.to = boost::shared_ptr<std::ostream>(new std::ostream(&*run.toBuf));
run.fromBuf = boost::shared_ptr<stdio_filebuf>(new stdio_filebuf(fromPipe.readSide.borrow(), std::ios_base::in));
run.from = boost::shared_ptr<std::istream>(new std::istream(&*run.fromBuf));
}
bool LocalStore::hasSubstitutes(const Path & path)
{
if (!substitutablePathsLoaded)
querySubstitutablePaths();
return substitutablePaths.find(path) != substitutablePaths.end();
foreach (Paths::iterator, i, substituters) {
RunningSubstituter & run(runningSubstituters[*i]);
startSubstituter(*i, run);
*run.to << "have\n" << path << "\n" << std::flush;
string s;
int res;
getline(*run.from, s);
if (!string2Int(s, res)) abort();
if (res) return true;
}
return false;
}
bool LocalStore::querySubstitutablePathInfo(const Path & path,
SubstitutablePathInfo & info)
{
foreach (Paths::iterator, i, substituters) {
RunningSubstituter & run(runningSubstituters[*i]);
startSubstituter(*i, run);
*run.to << "info\n" << path << "\n" << std::flush;
string s;
int res;
getline(*run.from, s);
if (!string2Int(s, res)) abort();
if (res) {
getline(*run.from, info.deriver);
int nrRefs;
getline(*run.from, s);
if (!string2Int(s, nrRefs)) abort();
while (nrRefs--) {
Path p; getline(*run.from, p);
info.references.insert(p);
}
info.downloadSize = 0;
return true;
}
}
return false;
}

View file

@ -3,6 +3,8 @@
#include <string>
#include <ext/stdio_filebuf.h>
#include "store-api.hh"
#include "util.hh"
@ -34,12 +36,27 @@ struct OptimiseStats
};
typedef __gnu_cxx::stdio_filebuf<char> stdio_filebuf;
struct RunningSubstituter
{
Pid pid;
boost::shared_ptr<stdio_filebuf> toBuf, fromBuf;
boost::shared_ptr<std::ostream> to;
boost::shared_ptr<std::istream> from;
};
class LocalStore : public StoreAPI
{
private:
bool substitutablePathsLoaded;
PathSet substitutablePaths;
typedef std::map<Path, RunningSubstituter> RunningSubstituters;
RunningSubstituters runningSubstituters;
public:
/* Initialise the local store, upgrading the schema if
@ -66,6 +83,9 @@ public:
bool hasSubstitutes(const Path & path);
bool querySubstitutablePathInfo(const Path & path,
SubstitutablePathInfo & info);
Path addToStore(const Path & srcPath, bool fixed = false,
bool recursive = false, string hashAlgo = "",
PathFilter & filter = defaultPathFilter);
@ -147,6 +167,9 @@ private:
void tryToDelete(const GCOptions & options, GCResults & results,
const PathSet & livePaths, const PathSet & tempRootsClosed, PathSet & done,
const Path & path);
void startSubstituter(const Path & substituter,
RunningSubstituter & runningSubstituter);
};

View file

@ -1,5 +1,6 @@
#include "misc.hh"
#include "store-api.hh"
#include "local-store.hh"
#include <aterm2.h>
@ -79,10 +80,13 @@ void queryMissing(const PathSet & targets,
else {
if (store->isValidPath(p)) continue;
if (store->hasSubstitutes(p))
SubstitutablePathInfo info;
if (dynamic_cast<LocalStore *>(store.get())->querySubstitutablePathInfo(p, info)) {
willSubstitute.insert(p);
// XXX call the substituters
// store->queryReferences(p, todo);
todo.insert(info.references.begin(), info.references.end());
}
/* Not substitutable and not buildable; should we flag
this? */
}
}
}

View file

@ -213,6 +213,13 @@ bool RemoteStore::hasSubstitutes(const Path & path)
}
bool RemoteStore::querySubstitutablePathInfo(const Path & path,
SubstitutablePathInfo & info)
{
throw Error("not implemented");
}
Hash RemoteStore::queryPathHash(const Path & path)
{
writeInt(wopQueryPathHash, to);
@ -256,12 +263,6 @@ Path RemoteStore::queryDeriver(const Path & path)
}
PathSet RemoteStore::querySubstitutablePaths()
{
throw Error("not implemented");
}
Path RemoteStore::addToStore(const Path & _srcPath, bool fixed,
bool recursive, string hashAlgo, PathFilter & filter)
{

View file

@ -37,10 +37,11 @@ public:
Path queryDeriver(const Path & path);
PathSet querySubstitutablePaths();
bool hasSubstitutes(const Path & path);
bool querySubstitutablePathInfo(const Path & path,
SubstitutablePathInfo & info);
Path addToStore(const Path & srcPath, bool fixed = false,
bool recursive = false, string hashAlgo = "",
PathFilter & filter = defaultPathFilter);

View file

@ -17,13 +17,6 @@ GCOptions::GCOptions()
}
bool StoreAPI::hasSubstitutes(const Path & path)
{
PathSet paths = querySubstitutablePaths();
return paths.find(path) != paths.end();
}
bool isInStore(const Path & path)
{
return path[0] == '/'

View file

@ -88,6 +88,14 @@ struct GCResults
};
struct SubstitutablePathInfo
{
Path deriver;
PathSet references;
unsigned long long downloadSize; /* 0 = unknown or inapplicable */
};
class StoreAPI
{
public:
@ -117,12 +125,13 @@ public:
no deriver has been set. */
virtual Path queryDeriver(const Path & path) = 0;
/* Query the set of substitutable paths. */
virtual PathSet querySubstitutablePaths() = 0;
/* Query whether a path has substitutes. */
virtual bool hasSubstitutes(const Path & path) = 0;
/* More efficient variant if we just want to know if a path has
substitutes. */
virtual bool hasSubstitutes(const Path & path);
/* Query the references, deriver and download size of a
substitutable path. */
virtual bool querySubstitutablePathInfo(const Path & path,
SubstitutablePathInfo & info) = 0;
/* Copy the contents of a path to the store and register the
validity the resulting path. The resulting path is returned.

View file

@ -579,7 +579,14 @@ AutoCloseFD::AutoCloseFD(int fd)
AutoCloseFD::AutoCloseFD(const AutoCloseFD & fd)
{
abort();
/* Copying a AutoCloseFD isn't allowed (who should get to close
it?). But as a edge case, allow copying of closed
AutoCloseFDs. This is necessary due to tiresome reasons
involving copy constructor use on default object values in STL
containers (like when you do `map[value]' where value isn't in
the map yet). */
this->fd = fd.fd;
if (this->fd != -1) abort();
}
@ -832,7 +839,7 @@ string runProgram(Path program, bool searchPath, const Strings & args)
pipe.readSide.close();
if (dup2(pipe.writeSide, STDOUT_FILENO) == -1)
throw SysError("dupping from-hook write side");
throw SysError("dupping stdout");
std::vector<const char *> cargs; /* careful with c_str()! */
cargs.push_back(program.c_str());
@ -868,6 +875,17 @@ string runProgram(Path program, bool searchPath, const Strings & args)
}
void closeMostFDs(const set<int> & exceptions)
{
int maxFD = 0;
maxFD = sysconf(_SC_OPEN_MAX);
for (int fd = 0; fd < maxFD; ++fd)
if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO
&& exceptions.find(fd) == exceptions.end())
close(fd); /* ignore result */
}
void quickExit(int status)
{
#ifdef __CYGWIN__

View file

@ -245,6 +245,10 @@ void killUser(uid_t uid);
string runProgram(Path program, bool searchPath = false,
const Strings & args = Strings());
/* Close all file descriptors except stdin, stdout, stderr, and those
listed in the given set. Good practice in child processes. */
void closeMostFDs(const set<int> & exceptions);
/* Wrapper around _exit() on Unix and ExitProcess() on Windows. (On
Cygwin, _exit() doesn't seem to do the right thing.) */
void quickExit(int status);

View file

@ -1,14 +1,25 @@
#! /bin/sh -e
echo substituter args: $* >&2
if test $1 = "--query-paths"; then
cat $TEST_ROOT/sub-paths
elif test $1 = "--query-info"; then
shift
for i in in $@; do
echo $i
echo "" # deriver
echo 0 # nr of refs
if test $1 = "--query"; then
while read cmd; do
echo FOO $cmd >&2
if test "$cmd" = "have"; then
read path
if grep -q "$path" $TEST_ROOT/sub-paths; then
echo 1
else
echo 0
fi
elif test "$cmd" = "info"; then
read path
echo 1
echo "" # deriver
echo 0 # nr of refs
else
echo "bad command $cmd"
exit 1
fi
done
elif test $1 = "--substitute"; then
mkdir $2

View file

@ -1,14 +1,24 @@
#! /bin/sh -e
echo substituter2 args: $* >&2
if test $1 = "--query-paths"; then
cat $TEST_ROOT/sub-paths
elif test $1 = "--query-info"; then
shift
for i in in $@; do
echo $i
echo "" # deriver
echo 0 # nr of refs
if test $1 = "--query"; then
while read cmd; do
if test "$cmd" = "have"; then
read path
if grep -q "$path" $TEST_ROOT/sub-paths; then
echo 1
else
echo 0
fi
elif test "$cmd" = "info"; then
read path
echo 1
echo "" # deriver
echo 0 # nr of refs
else
echo "bad command $cmd"
exit 1
fi
done
elif test $1 = "--substitute"; then
exit 1