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Use Boost's regex implementation instead of libstdc++'s
The latter runs in unbounded stack space so it crashes on large
inputs.
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edolstra committed Feb 17, 2021
1 parent 6042feb commit e594de7
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Showing 4 changed files with 18 additions and 13 deletions.
2 changes: 1 addition & 1 deletion flake.nix
Expand Up @@ -135,7 +135,7 @@
# Copy libboost_context so we don't get all of Boost in our closure.
# https://github.com/NixOS/nixpkgs/issues/45462
mkdir -p $out/lib
cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*} $out/lib
cp -pd ${boost}/lib/{libboost_context*,libboost_thread*,libboost_system*,libboost_regex*} $out/lib
rm -f $out/lib/*.a
${lib.optionalString stdenv.isLinux ''
chmod u+w $out/lib/*.so.*
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6 changes: 6 additions & 0 deletions src/libutil/regex.hh
@@ -0,0 +1,6 @@
#pragma once

#include <boost/regex.hpp>

namespace regex = boost;

21 changes: 10 additions & 11 deletions src/nix/develop.cc
Expand Up @@ -6,8 +6,7 @@
#include "derivations.hh"
#include "affinity.hh"
#include "progress-bar.hh"

#include <regex>
#include "regex.hh"

using namespace nix;

Expand Down Expand Up @@ -64,42 +63,42 @@ BuildEnvironment readEnvironment(const Path & path)
static std::string indexedArrayRegex =
R"re((?:\(( *\[[0-9]+\]="(?:[^"\\]|\\.)*")*\)))re";

static std::regex declareRegex(
static regex::regex declareRegex(
"^declare -a?x (" + varNameRegex + ")(=(" +
dquotedStringRegex + "|" + indexedArrayRegex + "))?\n");

static std::regex varRegex(
static regex::regex varRegex(
"^(" + varNameRegex + ")=(" + simpleStringRegex + "|" + squotedStringRegex + "|" + indexedArrayRegex + ")\n");

/* Note: we distinguish between an indexed and associative array
using the space before the closing parenthesis. Will
undoubtedly regret this some day. */
static std::regex assocArrayRegex(
static regex::regex assocArrayRegex(
"^(" + varNameRegex + ")=" + R"re((?:\(( *\[[^\]]+\]="(?:[^"\\]|\\.)*")* *\)))re" + "\n");

static std::regex functionRegex(
static regex::regex functionRegex(
"^" + varNameRegex + " \\(\\) *\n");

while (pos != file.end()) {

std::smatch match;
regex::smatch match;

if (std::regex_search(pos, file.cend(), match, declareRegex, std::regex_constants::match_continuous)) {
if (regex::regex_search(pos, file.cend(), match, declareRegex, regex::regex_constants::match_continuous)) {
pos = match[0].second;
exported.insert(match[1]);
}

else if (std::regex_search(pos, file.cend(), match, varRegex, std::regex_constants::match_continuous)) {
else if (regex::regex_search(pos, file.cend(), match, varRegex, regex::regex_constants::match_continuous)) {
pos = match[0].second;
res.env.insert({match[1], Var { .exported = exported.count(match[1]) > 0, .quoted = match[2] }});
}

else if (std::regex_search(pos, file.cend(), match, assocArrayRegex, std::regex_constants::match_continuous)) {
else if (regex::regex_search(pos, file.cend(), match, assocArrayRegex, regex::regex_constants::match_continuous)) {
pos = match[0].second;
res.env.insert({match[1], Var { .associative = true, .quoted = match[2] }});
}

else if (std::regex_search(pos, file.cend(), match, functionRegex, std::regex_constants::match_continuous)) {
else if (regex::regex_search(pos, file.cend(), match, functionRegex, regex::regex_constants::match_continuous)) {
res.bashFunctions = std::string(pos, file.cend());
break;
}
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2 changes: 1 addition & 1 deletion src/nix/local.mk
Expand Up @@ -18,7 +18,7 @@ nix_CXXFLAGS += -I src/libutil -I src/libstore -I src/libfetchers -I src/libexpr

nix_LIBS = libexpr libmain libfetchers libstore libutil libcmd

nix_LDFLAGS = -pthread $(SODIUM_LIBS) $(EDITLINE_LIBS) $(BOOST_LDFLAGS) -llowdown
nix_LDFLAGS = -pthread $(SODIUM_LIBS) $(EDITLINE_LIBS) $(BOOST_LDFLAGS) -llowdown -lboost_regex

$(foreach name, \
nix-build nix-channel nix-collect-garbage nix-copy-closure nix-daemon nix-env nix-hash nix-instantiate nix-prefetch-url nix-shell nix-store, \
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