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edolstraedolstra
committedMar 30, 2020
Backport 'nix dev-shell' from the flakes branch
This also adds a '--profile' option to 'nix build' (replacing 'nix-env --set').
·
2.28.02.4pre-rc1
1 parent 367577d commit e1a94ad

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9 files changed

+569
-116
lines changed

9 files changed

+569
-116
lines changed
 

‎src/libutil/util.cc

+11
Original file line numberDiff line numberDiff line change
@@ -478,6 +478,17 @@ Path createTempDir(const Path & tmpRoot, const Path & prefix,
478478
}
479479

480480

481+
std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix)
482+
{
483+
Path tmpl(getEnv("TMPDIR").value_or("/tmp") + "/" + prefix + ".XXXXXX");
484+
// Strictly speaking, this is UB, but who cares...
485+
AutoCloseFD fd(mkstemp((char *) tmpl.c_str()));
486+
if (!fd)
487+
throw SysError("creating temporary file '%s'", tmpl);
488+
return {std::move(fd), tmpl};
489+
}
490+
491+
481492
std::string getUserName()
482493
{
483494
auto pw = getpwuid(geteuid());

‎src/libutil/util.hh

+8-4
Original file line numberDiff line numberDiff line change
@@ -122,10 +122,6 @@ void deletePath(const Path & path);
122122

123123
void deletePath(const Path & path, unsigned long long & bytesFreed);
124124

125-
/* Create a temporary directory. */
126-
Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
127-
bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755);
128-
129125
std::string getUserName();
130126

131127
/* Return $HOME or the user's home directory from /etc/passwd. */
@@ -205,6 +201,14 @@ public:
205201
};
206202

207203

204+
/* Create a temporary directory. */
205+
Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
206+
bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755);
207+
208+
/* Create a temporary file, returning a file handle and its path. */
209+
std::pair<AutoCloseFD, Path> createTempFile(const Path & prefix = "nix");
210+
211+
208212
class Pipe
209213
{
210214
public:

‎src/nix/build.cc

+11-6
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,7 @@
55

66
using namespace nix;
77

8-
struct CmdBuild : MixDryRun, InstallablesCommand
8+
struct CmdBuild : InstallablesCommand, MixDryRun, MixProfile
99
{
1010
Path outLink = "result";
1111

@@ -40,6 +40,10 @@ struct CmdBuild : MixDryRun, InstallablesCommand
4040
"To build the build.x86_64-linux attribute from release.nix:",
4141
"nix build -f release.nix build.x86_64-linux"
4242
},
43+
Example{
44+
"To make a profile point at GNU Hello:",
45+
"nix build --profile /tmp/profile nixpkgs.hello"
46+
},
4347
};
4448
}
4549

@@ -49,18 +53,19 @@ struct CmdBuild : MixDryRun, InstallablesCommand
4953

5054
if (dryRun) return;
5155

52-
for (size_t i = 0; i < buildables.size(); ++i) {
53-
auto & b(buildables[i]);
54-
55-
if (outLink != "")
56-
for (auto & output : b.outputs)
56+
if (outLink != "") {
57+
for (size_t i = 0; i < buildables.size(); ++i) {
58+
for (auto & output : buildables[i].outputs)
5759
if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
5860
std::string symlink = outLink;
5961
if (i) symlink += fmt("-%d", i);
6062
if (output.first != "out") symlink += fmt("-%s", output.first);
6163
store2->addPermRoot(output.second, absPath(symlink), true);
6264
}
65+
}
6366
}
67+
68+
updateProfile(buildables);
6469
}
6570
};
6671

‎src/nix/command.cc

+94
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,9 @@
22
#include "store-api.hh"
33
#include "derivations.hh"
44
#include "nixexpr.hh"
5+
#include "profiles.hh"
6+
7+
extern char * * environ;
58

69
namespace nix {
710

@@ -96,4 +99,95 @@ Strings editorFor(const Pos & pos)
9699
return args;
97100
}
98101

102+
MixProfile::MixProfile()
103+
{
104+
mkFlag()
105+
.longName("profile")
106+
.description("profile to update")
107+
.labels({"path"})
108+
.dest(&profile);
109+
}
110+
111+
void MixProfile::updateProfile(const StorePath & storePath)
112+
{
113+
if (!profile) return;
114+
auto store = getStore().dynamic_pointer_cast<LocalFSStore>();
115+
if (!store) throw Error("'--profile' is not supported for this Nix store");
116+
auto profile2 = absPath(*profile);
117+
switchLink(profile2,
118+
createGeneration(
119+
ref<LocalFSStore>(store),
120+
profile2, store->printStorePath(storePath)));
121+
}
122+
123+
void MixProfile::updateProfile(const Buildables & buildables)
124+
{
125+
if (!profile) return;
126+
127+
std::optional<StorePath> result;
128+
129+
for (auto & buildable : buildables) {
130+
for (auto & output : buildable.outputs) {
131+
if (result)
132+
throw Error("'--profile' requires that the arguments produce a single store path, but there are multiple");
133+
result = output.second.clone();
134+
}
135+
}
136+
137+
if (!result)
138+
throw Error("'--profile' requires that the arguments produce a single store path, but there are none");
139+
140+
updateProfile(*result);
141+
}
142+
143+
MixDefaultProfile::MixDefaultProfile()
144+
{
145+
profile = getDefaultProfile();
146+
}
147+
148+
MixEnvironment::MixEnvironment() : ignoreEnvironment(false) {
149+
mkFlag()
150+
.longName("ignore-environment")
151+
.shortName('i')
152+
.description("clear the entire environment (except those specified with --keep)")
153+
.set(&ignoreEnvironment, true);
154+
155+
mkFlag()
156+
.longName("keep")
157+
.shortName('k')
158+
.description("keep specified environment variable")
159+
.arity(1)
160+
.labels({"name"})
161+
.handler([&](std::vector<std::string> ss) { keep.insert(ss.front()); });
162+
163+
mkFlag()
164+
.longName("unset")
165+
.shortName('u')
166+
.description("unset specified environment variable")
167+
.arity(1)
168+
.labels({"name"})
169+
.handler([&](std::vector<std::string> ss) { unset.insert(ss.front()); });
170+
}
171+
172+
void MixEnvironment::setEnviron() {
173+
if (ignoreEnvironment) {
174+
if (!unset.empty())
175+
throw UsageError("--unset does not make sense with --ignore-environment");
176+
177+
for (const auto & var : keep) {
178+
auto val = getenv(var.c_str());
179+
if (val) stringsEnv.emplace_back(fmt("%s=%s", var.c_str(), val));
180+
}
181+
182+
vectorEnv = stringsToCharPtrs(stringsEnv);
183+
environ = vectorEnv.data();
184+
} else {
185+
if (!keep.empty())
186+
throw UsageError("--keep does not make sense without --ignore-environment");
187+
188+
for (const auto & var : unset)
189+
unsetenv(var.c_str());
190+
}
191+
}
192+
99193
}

‎src/nix/command.hh

+34-28
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
#pragma once
22

3+
#include "installables.hh"
34
#include "args.hh"
45
#include "common-eval-args.hh"
56
#include "path.hh"
@@ -22,34 +23,7 @@ private:
2223
std::shared_ptr<Store> _store;
2324
};
2425

25-
struct Buildable
26-
{
27-
std::optional<StorePath> drvPath;
28-
std::map<std::string, StorePath> outputs;
29-
};
30-
31-
typedef std::vector<Buildable> Buildables;
32-
33-
struct Installable
34-
{
35-
virtual ~Installable() { }
36-
37-
virtual std::string what() = 0;
38-
39-
virtual Buildables toBuildables()
40-
{
41-
throw Error("argument '%s' cannot be built", what());
42-
}
43-
44-
Buildable toBuildable();
45-
46-
virtual std::pair<Value *, Pos> toValue(EvalState & state)
47-
{
48-
throw Error("argument '%s' cannot be evaluated", what());
49-
}
50-
};
51-
52-
struct SourceExprCommand : virtual Args, StoreCommand, MixEvalArgs
26+
struct SourceExprCommand : virtual StoreCommand, MixEvalArgs
5327
{
5428
Path file;
5529

@@ -184,4 +158,36 @@ std::set<StorePath> toDerivations(ref<Store> store,
184158
filename:lineno. */
185159
Strings editorFor(const Pos & pos);
186160

161+
struct MixProfile : virtual StoreCommand
162+
{
163+
std::optional<Path> profile;
164+
165+
MixProfile();
166+
167+
/* If 'profile' is set, make it point at 'storePath'. */
168+
void updateProfile(const StorePath & storePath);
169+
170+
/* If 'profile' is set, make it point at the store path produced
171+
by 'buildables'. */
172+
void updateProfile(const Buildables & buildables);
173+
};
174+
175+
struct MixDefaultProfile : MixProfile
176+
{
177+
MixDefaultProfile();
178+
};
179+
180+
struct MixEnvironment : virtual Args {
181+
182+
StringSet keep, unset;
183+
Strings stringsEnv;
184+
std::vector<char*> vectorEnv;
185+
bool ignoreEnvironment;
186+
187+
MixEnvironment();
188+
189+
/* Modify global environ based on ignoreEnvironment, keep, and unset. It's expected that exec will be called before this class goes out of scope, otherwise environ will become invalid. */
190+
void setEnviron();
191+
};
192+
187193
}

‎src/nix/installables.cc

+5
Original file line numberDiff line numberDiff line change
@@ -109,6 +109,11 @@ struct InstallableStorePath : Installable
109109
bs.push_back(std::move(b));
110110
return bs;
111111
}
112+
113+
std::optional<StorePath> getStorePath() override
114+
{
115+
return storePath.clone();
116+
}
112117
};
113118

114119
struct InstallableValue : Installable

‎src/nix/installables.hh

+45
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,45 @@
1+
#pragma once
2+
3+
#include "util.hh"
4+
#include "path.hh"
5+
#include "eval.hh"
6+
7+
#include <optional>
8+
9+
namespace nix {
10+
11+
struct Buildable
12+
{
13+
std::optional<StorePath> drvPath;
14+
std::map<std::string, StorePath> outputs;
15+
};
16+
17+
typedef std::vector<Buildable> Buildables;
18+
19+
struct Installable
20+
{
21+
virtual ~Installable() { }
22+
23+
virtual std::string what() = 0;
24+
25+
virtual Buildables toBuildables()
26+
{
27+
throw Error("argument '%s' cannot be built", what());
28+
}
29+
30+
Buildable toBuildable();
31+
32+
virtual std::pair<Value *, Pos> toValue(EvalState & state)
33+
{
34+
throw Error("argument '%s' cannot be evaluated", what());
35+
}
36+
37+
/* Return a value only if this installable is a store path or a
38+
symlink to it. */
39+
virtual std::optional<StorePath> getStorePath()
40+
{
41+
return {};
42+
}
43+
};
44+
45+
}

‎src/nix/run.cc

+42-78
Original file line numberDiff line numberDiff line change
@@ -8,6 +8,7 @@
88
#include "fs-accessor.hh"
99
#include "progress-bar.hh"
1010
#include "affinity.hh"
11+
#include "eval.hh"
1112

1213
#if __linux__
1314
#include <sys/mount.h>
@@ -19,11 +20,46 @@ using namespace nix;
1920

2021
std::string chrootHelperName = "__run_in_chroot";
2122

22-
struct CmdRun : InstallablesCommand
23+
struct RunCommon : virtual Command
24+
{
25+
void runProgram(ref<Store> store,
26+
const std::string & program,
27+
const Strings & args)
28+
{
29+
stopProgressBar();
30+
31+
restoreSignals();
32+
33+
restoreAffinity();
34+
35+
/* If this is a diverted store (i.e. its "logical" location
36+
(typically /nix/store) differs from its "physical" location
37+
(e.g. /home/eelco/nix/store), then run the command in a
38+
chroot. For non-root users, this requires running it in new
39+
mount and user namespaces. Unfortunately,
40+
unshare(CLONE_NEWUSER) doesn't work in a multithreaded
41+
program (which "nix" is), so we exec() a single-threaded
42+
helper program (chrootHelper() below) to do the work. */
43+
auto store2 = store.dynamic_pointer_cast<LocalStore>();
44+
45+
if (store2 && store->storeDir != store2->realStoreDir) {
46+
Strings helperArgs = { chrootHelperName, store->storeDir, store2->realStoreDir, program };
47+
for (auto & arg : args) helperArgs.push_back(arg);
48+
49+
execv(readLink("/proc/self/exe").c_str(), stringsToCharPtrs(helperArgs).data());
50+
51+
throw SysError("could not execute chroot helper");
52+
}
53+
54+
execvp(program.c_str(), stringsToCharPtrs(args).data());
55+
56+
throw SysError("unable to execute '%s'", program);
57+
}
58+
};
59+
60+
struct CmdRun : InstallablesCommand, RunCommon, MixEnvironment
2361
{
2462
std::vector<std::string> command = { "bash" };
25-
StringSet keep, unset;
26-
bool ignoreEnvironment = false;
2763

2864
CmdRun()
2965
{
@@ -37,28 +73,6 @@ struct CmdRun : InstallablesCommand
3773
if (ss.empty()) throw UsageError("--command requires at least one argument");
3874
command = ss;
3975
});
40-
41-
mkFlag()
42-
.longName("ignore-environment")
43-
.shortName('i')
44-
.description("clear the entire environment (except those specified with --keep)")
45-
.set(&ignoreEnvironment, true);
46-
47-
mkFlag()
48-
.longName("keep")
49-
.shortName('k')
50-
.description("keep specified environment variable")
51-
.arity(1)
52-
.labels({"name"})
53-
.handler([&](std::vector<std::string> ss) { keep.insert(ss.front()); });
54-
55-
mkFlag()
56-
.longName("unset")
57-
.shortName('u')
58-
.description("unset specified environment variable")
59-
.arity(1)
60-
.labels({"name"})
61-
.handler([&](std::vector<std::string> ss) { unset.insert(ss.front()); });
6276
}
6377

6478
std::string description() override
@@ -94,35 +108,13 @@ struct CmdRun : InstallablesCommand
94108

95109
auto accessor = store->getFSAccessor();
96110

97-
if (ignoreEnvironment) {
98-
99-
if (!unset.empty())
100-
throw UsageError("--unset does not make sense with --ignore-environment");
101-
102-
std::map<std::string, std::string> kept;
103-
for (auto & var : keep) {
104-
auto s = getenv(var.c_str());
105-
if (s) kept[var] = s;
106-
}
107-
108-
clearEnv();
109-
110-
for (auto & var : kept)
111-
setenv(var.first.c_str(), var.second.c_str(), 1);
112-
113-
} else {
114-
115-
if (!keep.empty())
116-
throw UsageError("--keep does not make sense without --ignore-environment");
117-
118-
for (auto & var : unset)
119-
unsetenv(var.c_str());
120-
}
121111

122112
std::unordered_set<StorePath> done;
123113
std::queue<StorePath> todo;
124114
for (auto & path : outPaths) todo.push(path.clone());
125115

116+
setEnviron();
117+
126118
auto unixPath = tokenizeString<Strings>(getEnv("PATH").value_or(""), ":");
127119

128120
while (!todo.empty()) {
@@ -142,38 +134,10 @@ struct CmdRun : InstallablesCommand
142134

143135
setenv("PATH", concatStringsSep(":", unixPath).c_str(), 1);
144136

145-
std::string cmd = *command.begin();
146137
Strings args;
147138
for (auto & arg : command) args.push_back(arg);
148139

149-
stopProgressBar();
150-
151-
restoreSignals();
152-
153-
restoreAffinity();
154-
155-
/* If this is a diverted store (i.e. its "logical" location
156-
(typically /nix/store) differs from its "physical" location
157-
(e.g. /home/eelco/nix/store), then run the command in a
158-
chroot. For non-root users, this requires running it in new
159-
mount and user namespaces. Unfortunately,
160-
unshare(CLONE_NEWUSER) doesn't work in a multithreaded
161-
program (which "nix" is), so we exec() a single-threaded
162-
helper program (chrootHelper() below) to do the work. */
163-
auto store2 = store.dynamic_pointer_cast<LocalStore>();
164-
165-
if (store2 && store->storeDir != store2->realStoreDir) {
166-
Strings helperArgs = { chrootHelperName, store->storeDir, store2->realStoreDir, cmd };
167-
for (auto & arg : args) helperArgs.push_back(arg);
168-
169-
execv(readLink("/proc/self/exe").c_str(), stringsToCharPtrs(helperArgs).data());
170-
171-
throw SysError("could not execute chroot helper");
172-
}
173-
174-
execvp(cmd.c_str(), stringsToCharPtrs(args).data());
175-
176-
throw SysError("unable to exec '%s'", cmd);
140+
runProgram(store, *command.begin(), args);
177141
}
178142
};
179143

‎src/nix/shell.cc

+319
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,319 @@
1+
#include "eval.hh"
2+
#include "command.hh"
3+
#include "common-args.hh"
4+
#include "shared.hh"
5+
#include "store-api.hh"
6+
#include "derivations.hh"
7+
#include "affinity.hh"
8+
#include "progress-bar.hh"
9+
10+
#include <regex>
11+
12+
using namespace nix;
13+
14+
struct Var
15+
{
16+
bool exported;
17+
std::string value; // quoted string or array
18+
};
19+
20+
struct BuildEnvironment
21+
{
22+
std::map<std::string, Var> env;
23+
std::string bashFunctions;
24+
};
25+
26+
BuildEnvironment readEnvironment(const Path & path)
27+
{
28+
BuildEnvironment res;
29+
30+
std::set<std::string> exported;
31+
32+
debug("reading environment file '%s'", path);
33+
34+
auto file = readFile(path);
35+
36+
auto pos = file.cbegin();
37+
38+
static std::string varNameRegex =
39+
R"re((?:[a-zA-Z_][a-zA-Z0-9_]*))re";
40+
41+
static std::regex declareRegex(
42+
"^declare -x (" + varNameRegex + ")" +
43+
R"re((?:="((?:[^"\\]|\\.)*)")?\n)re");
44+
45+
static std::string simpleStringRegex =
46+
R"re((?:[a-zA-Z0-9_/:\.\-\+=]*))re";
47+
48+
static std::string quotedStringRegex =
49+
R"re((?:\$?'(?:[^'\\]|\\[abeEfnrtv\\'"?])*'))re";
50+
51+
static std::string arrayRegex =
52+
R"re((?:\(( *\[[^\]]+\]="(?:[^"\\]|\\.)*")*\)))re";
53+
54+
static std::regex varRegex(
55+
"^(" + varNameRegex + ")=(" + simpleStringRegex + "|" + quotedStringRegex + "|" + arrayRegex + ")\n");
56+
57+
static std::regex functionRegex(
58+
"^" + varNameRegex + " \\(\\) *\n");
59+
60+
while (pos != file.end()) {
61+
62+
std::smatch match;
63+
64+
if (std::regex_search(pos, file.cend(), match, declareRegex)) {
65+
pos = match[0].second;
66+
exported.insert(match[1]);
67+
}
68+
69+
else if (std::regex_search(pos, file.cend(), match, varRegex)) {
70+
pos = match[0].second;
71+
res.env.insert({match[1], Var { (bool) exported.count(match[1]), match[2] }});
72+
}
73+
74+
else if (std::regex_search(pos, file.cend(), match, functionRegex)) {
75+
res.bashFunctions = std::string(pos, file.cend());
76+
break;
77+
}
78+
79+
else throw Error("shell environment '%s' has unexpected line '%s'",
80+
path, file.substr(pos - file.cbegin(), 60));
81+
}
82+
83+
return res;
84+
}
85+
86+
/* Given an existing derivation, return the shell environment as
87+
initialised by stdenv's setup script. We do this by building a
88+
modified derivation with the same dependencies and nearly the same
89+
initial environment variables, that just writes the resulting
90+
environment to a file and exits. */
91+
StorePath getDerivationEnvironment(ref<Store> store, Derivation drv)
92+
{
93+
auto builder = baseNameOf(drv.builder);
94+
if (builder != "bash")
95+
throw Error("'nix shell' only works on derivations that use 'bash' as their builder");
96+
97+
drv.args = {
98+
"-c",
99+
"set -e; "
100+
"export IN_NIX_SHELL=impure; "
101+
"export dontAddDisableDepTrack=1; "
102+
"if [[ -n $stdenv ]]; then "
103+
" source $stdenv/setup; "
104+
"fi; "
105+
"export > $out; "
106+
"set >> $out "};
107+
108+
/* Remove derivation checks. */
109+
drv.env.erase("allowedReferences");
110+
drv.env.erase("allowedRequisites");
111+
drv.env.erase("disallowedReferences");
112+
drv.env.erase("disallowedRequisites");
113+
114+
// FIXME: handle structured attrs
115+
116+
/* Rehash and write the derivation. FIXME: would be nice to use
117+
'buildDerivation', but that's privileged. */
118+
auto drvName = drv.env["name"] + "-env";
119+
for (auto & output : drv.outputs)
120+
drv.env.erase(output.first);
121+
drv.env["out"] = "";
122+
drv.env["outputs"] = "out";
123+
Hash h = hashDerivationModulo(*store, drv, true);
124+
auto shellOutPath = store->makeOutputPath("out", h, drvName);
125+
drv.outputs.insert_or_assign("out", DerivationOutput(shellOutPath.clone(), "", ""));
126+
drv.env["out"] = store->printStorePath(shellOutPath);
127+
auto shellDrvPath2 = writeDerivation(store, drv, drvName);
128+
129+
/* Build the derivation. */
130+
store->buildPaths({shellDrvPath2});
131+
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assert(store->isValidPath(shellOutPath));
133+
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return shellOutPath;
135+
}
136+
137+
struct Common : InstallableCommand, MixProfile
138+
{
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std::set<string> ignoreVars{
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"BASHOPTS",
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"EUID",
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"HOME", // FIXME: don't ignore in pure mode?
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"NIX_BUILD_TOP",
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"NIX_ENFORCE_PURITY",
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"NIX_LOG_FD",
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"PPID",
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"PWD",
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"SHELLOPTS",
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"SHLVL",
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"SSL_CERT_FILE", // FIXME: only want to ignore /no-cert-file.crt
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"TEMP",
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"TEMPDIR",
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"TERM",
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"TMP",
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"TMPDIR",
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"TZ",
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"UID",
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};
159+
160+
void makeRcScript(const BuildEnvironment & buildEnvironment, std::ostream & out)
161+
{
162+
out << "nix_saved_PATH=\"$PATH\"\n";
163+
164+
for (auto & i : buildEnvironment.env) {
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if (!ignoreVars.count(i.first) && !hasPrefix(i.first, "BASH_")) {
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out << fmt("%s=%s\n", i.first, i.second.value);
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if (i.second.exported)
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out << fmt("export %s\n", i.first);
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}
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}
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out << "PATH=\"$PATH:$nix_saved_PATH\"\n";
173+
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out << buildEnvironment.bashFunctions << "\n";
175+
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// FIXME: set outputs
177+
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out << "export NIX_BUILD_TOP=\"$(mktemp -d --tmpdir nix-shell.XXXXXX)\"\n";
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for (auto & i : {"TMP", "TMPDIR", "TEMP", "TEMPDIR"})
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out << fmt("export %s=\"$NIX_BUILD_TOP\"\n", i);
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out << "eval \"$shellHook\"\n";
183+
}
184+
185+
StorePath getShellOutPath(ref<Store> store)
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{
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auto path = installable->getStorePath();
188+
if (path && hasSuffix(path->to_string(), "-env"))
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return path->clone();
190+
else {
191+
auto drvs = toDerivations(store, {installable});
192+
193+
if (drvs.size() != 1)
194+
throw Error("'%s' needs to evaluate to a single derivation, but it evaluated to %d derivations",
195+
installable->what(), drvs.size());
196+
197+
auto & drvPath = *drvs.begin();
198+
199+
return getDerivationEnvironment(store, store->derivationFromPath(drvPath));
200+
}
201+
}
202+
203+
BuildEnvironment getBuildEnvironment(ref<Store> store)
204+
{
205+
auto shellOutPath = getShellOutPath(store);
206+
207+
updateProfile(shellOutPath);
208+
209+
return readEnvironment(store->printStorePath(shellOutPath));
210+
}
211+
};
212+
213+
struct CmdDevShell : Common, MixEnvironment
214+
{
215+
std::vector<std::string> command;
216+
217+
CmdDevShell()
218+
{
219+
mkFlag()
220+
.longName("command")
221+
.shortName('c')
222+
.description("command and arguments to be executed insted of an interactive shell")
223+
.labels({"command", "args"})
224+
.arity(ArityAny)
225+
.handler([&](std::vector<std::string> ss) {
226+
if (ss.empty()) throw UsageError("--command requires at least one argument");
227+
command = ss;
228+
});
229+
}
230+
231+
std::string description() override
232+
{
233+
return "run a bash shell that provides the build environment of a derivation";
234+
}
235+
236+
Examples examples() override
237+
{
238+
return {
239+
Example{
240+
"To get the build environment of GNU hello:",
241+
"nix dev-shell nixpkgs.hello"
242+
},
243+
Example{
244+
"To store the build environment in a profile:",
245+
"nix dev-shell --profile /tmp/my-shell nixpkgs.hello"
246+
},
247+
Example{
248+
"To use a build environment previously recorded in a profile:",
249+
"nix dev-shell /tmp/my-shell"
250+
},
251+
};
252+
}
253+
254+
void run(ref<Store> store) override
255+
{
256+
auto buildEnvironment = getBuildEnvironment(store);
257+
258+
auto [rcFileFd, rcFilePath] = createTempFile("nix-shell");
259+
260+
std::ostringstream ss;
261+
makeRcScript(buildEnvironment, ss);
262+
263+
ss << fmt("rm -f '%s'\n", rcFilePath);
264+
265+
if (!command.empty()) {
266+
std::vector<std::string> args;
267+
for (auto s : command)
268+
args.push_back(shellEscape(s));
269+
ss << fmt("exec %s\n", concatStringsSep(" ", args));
270+
}
271+
272+
writeFull(rcFileFd.get(), ss.str());
273+
274+
stopProgressBar();
275+
276+
auto shell = getEnv("SHELL").value_or("bash");
277+
278+
setEnviron();
279+
280+
auto args = Strings{std::string(baseNameOf(shell)), "--rcfile", rcFilePath};
281+
282+
restoreAffinity();
283+
restoreSignals();
284+
285+
execvp(shell.c_str(), stringsToCharPtrs(args).data());
286+
287+
throw SysError("executing shell '%s'", shell);
288+
}
289+
};
290+
291+
struct CmdPrintDevEnv : Common
292+
{
293+
std::string description() override
294+
{
295+
return "print shell code that can be sourced by bash to reproduce the build environment of a derivation";
296+
}
297+
298+
Examples examples() override
299+
{
300+
return {
301+
Example{
302+
"To apply the build environment of GNU hello to the current shell:",
303+
". <(nix print-dev-env nixpkgs.hello)"
304+
},
305+
};
306+
}
307+
308+
void run(ref<Store> store) override
309+
{
310+
auto buildEnvironment = getBuildEnvironment(store);
311+
312+
stopProgressBar();
313+
314+
makeRcScript(buildEnvironment, std::cout);
315+
}
316+
};
317+
318+
static auto r1 = registerCommand<CmdPrintDevEnv>("print-dev-env");
319+
static auto r2 = registerCommand<CmdDevShell>("dev-shell");

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