lix/src/nix-env/main.cc

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#include "globals.hh"
#include "normalise.hh"
#include "shared.hh"
#include "parser.hh"
#include "eval.hh"
typedef void (* Operation) (EvalState & state,
Strings opFlags, Strings opArgs);
struct DrvInfo
{
string name;
Path drvPath;
Path outPath;
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Hash drvHash;
};
typedef map<Path, DrvInfo> DrvInfos;
bool parseDerivation(EvalState & state, Expr e, DrvInfo & drv)
{
ATMatcher m;
e = evalExpr(state, e);
if (!(atMatch(m, e) >> "Attrs")) return false;
Expr a = queryAttr(e, "type");
if (!a || evalString(state, a) != "derivation") return false;
a = queryAttr(e, "name");
if (!a) throw badTerm("derivation name missing", e);
drv.name = evalString(state, a);
a = queryAttr(e, "drvPath");
if (!a) throw badTerm("derivation path missing", e);
drv.drvPath = evalPath(state, a);
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a = queryAttr(e, "drvHash");
if (!a) throw badTerm("derivation hash missing", e);
drv.drvHash = parseHash(evalString(state, a));
a = queryAttr(e, "outPath");
if (!a) throw badTerm("output path missing", e);
drv.outPath = evalPath(state, a);
return true;
}
bool parseDerivations(EvalState & state, Expr e, DrvInfos & drvs)
{
ATMatcher m;
ATermList es;
DrvInfo drv;
e = evalExpr(state, e);
if (parseDerivation(state, e, drv))
drvs[drv.drvPath] = drv;
else if (atMatch(m, e) >> "Attrs") {
ATermMap drvMap;
queryAllAttrs(e, drvMap);
for (ATermIterator i(drvMap.keys()); i; ++i) {
debug(format("evaluating attribute `%1%'") % *i);
if (parseDerivation(state, drvMap.get(*i), drv))
drvs[drv.drvPath] = drv;
}
}
else if (atMatch(m, e) >> "List" >> es) {
for (ATermIterator i(es); i; ++i) {
debug(format("evaluating list element"));
if (parseDerivation(state, *i, drv))
drvs[drv.drvPath] = drv;
}
}
return true;
}
void loadDerivations(EvalState & state, Path nePath, DrvInfos & drvs)
{
Expr e = parseExprFromFile(absPath(nePath));
if (!parseDerivations(state, e, drvs))
throw badTerm("expected set of derivations", e);
}
static Path getLinksDir()
{
return canonPath(nixStateDir + "/links");
}
static Path getCurrentPath()
{
return getLinksDir() + "/current";
}
void queryInstalled(EvalState & state, DrvInfos & drvs)
{
Path path = getCurrentPath() + "/manifest";
if (!pathExists(path)) return; /* not an error, assume nothing installed */
Expr e = ATreadFromNamedFile(path.c_str());
if (!e) throw Error(format("cannot read Nix expression from `%1%'") % path);
if (!parseDerivations(state, e, drvs))
throw badTerm(format("expected set of derivations in `%1%'") % path, e);
}
Path createLink(Path outPath, Path drvPath)
{
Path linksDir = getLinksDir();
unsigned int num = 0;
Strings names = readDirectory(linksDir);
for (Strings::iterator i = names.begin(); i != names.end(); ++i) {
istringstream s(*i);
unsigned int n;
if (s >> n && s.eof() && n >= num) num = n + 1;
}
Path linkPath;
while (1) {
linkPath = (format("%1%/%2%") % linksDir % num).str();
if (symlink(outPath.c_str(), linkPath.c_str()) == 0) break;
if (errno != EEXIST)
throw SysError(format("creating symlink `%1%'") % linkPath);
/* Somebody beat us to it, retry with a higher number. */
num++;
}
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writeStringToFile(linkPath + "-src.id", drvPath);
return linkPath;
}
void switchLink(Path link, Path target)
{
Path tmp = canonPath(dirOf(link) + "/.new_" + baseNameOf(link));
if (symlink(target.c_str(), tmp.c_str()) != 0)
throw SysError(format("creating symlink `%1%'") % tmp);
/* The rename() system call is supposed to be essentially atomic
on Unix. That is, if we have links `current -> X' and
`new_current -> Y', and we rename new_current to current, a
process accessing current will see X or Y, but never a
file-not-found or other error condition. This is sufficient to
atomically switch user environments. */
if (rename(tmp.c_str(), link.c_str()) != 0)
throw SysError(format("renaming `%1%' to `%2%'") % tmp % link);
}
void createUserEnv(EvalState & state, const DrvInfos & drvs)
{
/* Get the environment builder expression. */
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Expr envBuilder = parseExprFromFile(nixDataDir + "/nix/corepkgs/buildenv"); /* !!! */
/* Construct the whole top level derivation. */
ATermList inputs = ATempty;
for (DrvInfos::const_iterator i = drvs.begin();
i != drvs.end(); ++i)
{
ATerm t = ATmake(
"Attrs(["
"Bind(\"type\", Str(\"derivation\")), "
"Bind(\"name\", Str(<str>)), "
"Bind(\"drvPath\", Path(<str>)), "
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"Bind(\"drvHash\", Str(<str>)), "
"Bind(\"outPath\", Path(<str>))"
"])",
i->second.name.c_str(),
i->second.drvPath.c_str(),
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((string) i->second.drvHash).c_str(),
i->second.outPath.c_str());
inputs = ATinsert(inputs, t);
}
ATerm inputs2 = ATmake("List(<term>)", ATreverse(inputs));
/* Also write a copy of the list of inputs to the store; we need
it for future modifications of the environment. */
Path inputsFile = writeTerm(inputs2, "-env-inputs");
Expr topLevel = ATmake(
"Call(<term>, Attrs(["
"Bind(\"system\", Str(<str>)), "
"Bind(\"derivations\", <term>), " // !!! redundant
"Bind(\"manifest\", Path(<str>))"
"]))",
envBuilder, thisSystem.c_str(), inputs2, inputsFile.c_str());
/* Instantiate it. */
debug(format("evaluating builder expression `%1%'") % topLevel);
DrvInfo topLevelDrv;
if (!parseDerivation(state, topLevel, topLevelDrv))
abort();
/* Realise the resulting store expression. */
debug(format("realising user environment"));
Path nfPath = normaliseStoreExpr(topLevelDrv.drvPath);
realiseClosure(nfPath);
/* Switch the current user environment to the output path. */
debug(format("switching to new user environment"));
Path linkPath = createLink(topLevelDrv.outPath, topLevelDrv.drvPath);
switchLink(getLinksDir() + "/current", linkPath);
}
typedef map<string, Path> NameMap;
NameMap mapByNames(DrvInfos & drvs)
{
NameMap nameMap;
for (DrvInfos::iterator i = drvs.begin(); i != drvs.end(); ++i)
nameMap[i->second.name] = i->first;
return nameMap;
}
void installDerivations(EvalState & state,
Path nePath, Strings drvNames)
{
debug(format("installing derivations from `%1%'") % nePath);
/* Fetch all derivations from the input file. */
DrvInfos availDrvs;
loadDerivations(state, nePath, availDrvs);
NameMap nameMap = mapByNames(availDrvs);
/* Filter out the ones we're not interested in. */
DrvInfos selectedDrvs;
if (drvNames.size() > 0 && drvNames.front() == "*") { /* !!! hack */
selectedDrvs = availDrvs;
} else {
for (Strings::iterator i = drvNames.begin();
i != drvNames.end(); ++i)
{
NameMap::iterator j = nameMap.find(*i);
if (j == nameMap.end())
throw Error(format("unknown derivation `%1%'") % *i);
else
selectedDrvs[j->second] = availDrvs[j->second];
}
}
/* Add in the already installed derivations. */
DrvInfos installedDrvs;
queryInstalled(state, installedDrvs);
selectedDrvs.insert(installedDrvs.begin(), installedDrvs.end());
createUserEnv(state, selectedDrvs);
}
static void opInstall(EvalState & state,
Strings opFlags, Strings opArgs)
{
if (opArgs.size() < 1) throw UsageError("Nix file expected");
Path nePath = opArgs.front();
opArgs.pop_front();
installDerivations(state, nePath,
Strings(opArgs.begin(), opArgs.end()));
}
void uninstallDerivations(EvalState & state, Strings drvNames)
{
DrvInfos installedDrvs;
queryInstalled(state, installedDrvs);
NameMap nameMap = mapByNames(installedDrvs);
for (Strings::iterator i = drvNames.begin();
i != drvNames.end(); ++i)
{
NameMap::iterator j = nameMap.find(*i);
if (j == nameMap.end())
throw Error(format("unknown derivation `%1%'") % *i);
else
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installedDrvs.erase(j->second);
}
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createUserEnv(state, installedDrvs);
}
static void opUninstall(EvalState & state,
Strings opFlags, Strings opArgs)
{
uninstallDerivations(state, opArgs);
}
static void opQuery(EvalState & state,
Strings opFlags, Strings opArgs)
{
enum { qName, qDrvPath, qStatus } query = qName;
enum { sInstalled, sAvailable } source = sInstalled;
for (Strings::iterator i = opFlags.begin();
i != opFlags.end(); ++i)
if (*i == "--name") query = qName;
else if (*i == "--expr" || *i == "-e") query = qDrvPath;
else if (*i == "--status" || *i == "-s") query = qStatus;
else if (*i == "--installed") source = sInstalled;
else if (*i == "--available" || *i == "-f") source = sAvailable;
else throw UsageError(format("unknown flag `%1%'") % *i);
/* Obtain derivation information from the specified source. */
DrvInfos drvs;
switch (source) {
case sInstalled:
queryInstalled(state, drvs);
break;
case sAvailable: {
if (opArgs.size() < 1) throw UsageError("Nix file expected");
Path nePath = opArgs.front();
opArgs.pop_front();
loadDerivations(state, nePath, drvs);
break;
}
default: abort();
}
if (opArgs.size() != 0) throw UsageError("no arguments expected");
/* Perform the specified query on the derivations. */
switch (query) {
case qName: {
for (DrvInfos::iterator i = drvs.begin(); i != drvs.end(); ++i)
cout << format("%1%\n") % i->second.name;
break;
}
case qDrvPath: {
for (DrvInfos::iterator i = drvs.begin(); i != drvs.end(); ++i)
cout << format("%1%\n") % i->second.drvPath;
break;
}
case qStatus: {
DrvInfos installed;
queryInstalled(state, installed);
for (DrvInfos::iterator i = drvs.begin(); i != drvs.end(); ++i) {
cout << format("%1%%2% %3%\n")
% (installed.find(i->first) != installed.end() ? 'I' : '-')
% (isValidPath(i->second.outPath) ? 'P' : '-')
% i->second.name;
}
break;
}
default: abort();
}
}
void run(Strings args)
{
EvalState state;
Strings opFlags, opArgs;
Operation op = 0;
for (Strings::iterator i = args.begin(); i != args.end(); ++i) {
string arg = *i;
Operation oldOp = op;
if (arg == "--install" || arg == "-i")
op = opInstall;
else if (arg == "--uninstall" || arg == "-u")
op = opUninstall;
else if (arg == "--query" || arg == "-q")
op = opQuery;
else if (arg == "--verbose" || arg == "-v")
verbosity = (Verbosity) ((int) verbosity + 1);
else if (arg[0] == '-')
opFlags.push_back(arg);
else
opArgs.push_back(arg);
if (oldOp && oldOp != op)
throw UsageError("only one operation may be specified");
}
if (!op) throw UsageError("no operation specified");
openDB();
op(state, opFlags, opArgs);
printEvalStats(state);
}
string programId = "nix-env";