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Make <nix/fetchurl.nix> a builtin builder
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This ensures that 1) the derivation doesn't change when Nix changes;
2) the derivation closure doesn't contain Nix and its dependencies; 3)
we don't have to rely on ugly chroot hacks.
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edolstra committed Jul 20, 2015
1 parent eda2f36 commit 0a2bee3
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Showing 9 changed files with 61 additions and 20 deletions.
1 change: 0 additions & 1 deletion corepkgs/config.nix.in
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@ in rec {
tar = "@tar@";
tarFlags = "@tarFlags@";
tr = "@tr@";
curl = "@curl@";
nixBinDir = fromEnv "NIX_BIN_DIR" "@bindir@";
nixPrefix = "@prefix@";

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15 changes: 1 addition & 14 deletions corepkgs/fetchurl.nix
Original file line number Diff line number Diff line change
Expand Up @@ -5,20 +5,9 @@ with import <nix/config.nix>;
assert (outputHash != "" && outputHashAlgo != "")
|| md5 != "" || sha1 != "" || sha256 != "";

let

builder = builtins.toFile "fetchurl.sh"
(''
echo "downloading $url into $out"
${curl} --fail --location --max-redirs 20 --insecure "$url" > "$out"
'' + (if executable then "${coreutils}/chmod +x $out" else ""));

in

derivation {
name = baseNameOf (toString url);
builder = shell;
args = [ "-e" builder ];
builder = "builtin:fetchurl";

# New-style output content requirements.
outputHashAlgo = if outputHashAlgo != "" then outputHashAlgo else
Expand All @@ -39,6 +28,4 @@ derivation {
# by definition pure.
"http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
];

inherit chrootDeps;
}
2 changes: 1 addition & 1 deletion src/libexpr/local.mk
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ libexpr_SOURCES := $(wildcard $(d)/*.cc) $(d)/lexer-tab.cc $(d)/parser-tab.cc

libexpr_LIBS = libutil libstore libformat

libexpr_LDFLAGS = -ldl -lcurl
libexpr_LDFLAGS = -ldl

# The dependency on libgc must be propagated (i.e. meaning that
# programs/libraries that use libexpr must explicitly pass -lgc),
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28 changes: 25 additions & 3 deletions src/libstore/build.cc
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include "util.hh"
#include "archive.hh"
#include "affinity.hh"
#include "builtins.hh"

#include <map>
#include <sstream>
Expand Down Expand Up @@ -1269,6 +1270,12 @@ bool substitutesAllowed(const BasicDerivation & drv)
}


static bool isBuiltin(const BasicDerivation & drv)
{
return string(drv.builder, 0, 8) == "builtin:";
}


void DerivationGoal::tryToBuild()
{
trace("trying to build");
Expand Down Expand Up @@ -2139,7 +2146,7 @@ void DerivationGoal::startBuilder()
#endif
{
ProcessOptions options;
options.allowVfork = !buildUser.enabled();
options.allowVfork = !buildUser.enabled() && !isBuiltin(*drv);
pid = startProcess([&]() {
runChild();
}, options);
Expand Down Expand Up @@ -2386,7 +2393,9 @@ void DerivationGoal::runChild()
const char *builder = "invalid";

string sandboxProfile;
if (useChroot && SANDBOX_ENABLED) {
if (isBuiltin(*drv))
;
else if (useChroot && SANDBOX_ENABLED) {
/* Lots and lots and lots of file functions freak out if they can't stat their full ancestry */
PathSet ancestry;

Expand All @@ -2413,7 +2422,6 @@ void DerivationGoal::runChild()
for (auto & i : inputPaths)
dirsInChroot[i] = i;


/* TODO: we should factor out the policy cleanly, so we don't have to repeat the constants every time... */
sandboxProfile += "(version 1)\n";

Expand Down Expand Up @@ -2517,6 +2525,20 @@ void DerivationGoal::runChild()
}

/* Execute the program. This should not return. */
if (isBuiltin(*drv)) {
try {
logType = ltFlat;
if (drv->builder == "builtin:fetchurl")
builtinFetchurl(*drv);
else
throw Error(format("unsupported builtin function ‘%1%’") % string(drv->builder, 8));
_exit(0);
} catch (std::exception & e) {
writeFull(STDERR_FILENO, "error: " + string(e.what()) + "\n");
_exit(1);
}
}

execve(builder, stringsToCharPtrs(args).data(), stringsToCharPtrs(envStrs).data());

throw SysError(format("executing ‘%1%’") % drv->builder);
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24 changes: 24 additions & 0 deletions src/libstore/builtins.cc
Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
#include "builtins.hh"
#include "download.hh"

namespace nix {

void builtinFetchurl(const BasicDerivation & drv)
{
auto url = drv.env.find("url");
if (url == drv.env.end()) throw Error("attribute ‘url’ missing");
printMsg(lvlInfo, format("downloading ‘%1%’...") % url->second);
auto data = downloadFile(url->second); // FIXME: show progress

auto out = drv.env.find("out");
if (out == drv.env.end()) throw Error("attribute ‘url’ missing");
writeFile(out->second, data.data);

auto executable = drv.env.find("out");
if (executable != drv.env.end() && executable->second == "1") {
if (chmod(out->second.c_str(), 0755) == -1)
throw SysError(format("making ‘%1%’ executable") % out->second);
}
}

}
9 changes: 9 additions & 0 deletions src/libstore/builtins.hh
Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
#pragma once

#include "derivations.hh"

namespace nix {

void builtinFetchurl(const BasicDerivation & drv);

}
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File renamed without changes.
2 changes: 1 addition & 1 deletion src/libstore/local.mk
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ libstore_SOURCES := $(wildcard $(d)/*.cc)

libstore_LIBS = libutil libformat

libstore_LDFLAGS = -lsqlite3 -lbz2
libstore_LDFLAGS = -lsqlite3 -lbz2 -lcurl

ifeq ($(OS), SunOS)
libstore_LDFLAGS += -lsocket
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