From ffbad9b76279e23c70bd2df8ba5f3259180e192a Mon Sep 17 00:00:00 2001
From: Jade Lovelace <lix@jade.fyi>
Date: Wed, 27 Mar 2024 22:54:15 -0700
Subject: [PATCH] progress-bar.cc: fix signed overflow

this was caused by the use of std::chrono::duration::max() which gets
multiplied by some ratio to calculate nanoseconds to wait. then, it
explodes because that is a signed integer overflow. this was definitely
a bug.

error below:

/nix/store/fdiknsmnnczx6brsbppyljcs9hqckawk-gcc-12.3.0/include/c++/12.3.0/bits/chrono.h:225:38: runtime error: signed integer overflow: 9223372036854775807 * 1000000 cannot be represented in type 'long'
    #0 0x736d376b2b69 in std::chrono::duration<long, std::ratio<1l, 1000000000l>> std::chrono::__duration_cast_impl<std::chrono:
:duration<long, std::ratio<1l, 1000000000l>>, std::ratio<1000000l, 1l>, long, false, true>::__cast<long, std::ratio<1l, 1000l>>(
std::chrono::duration<long, std::ratio<1l, 1000l>> const&) /nix/store/fdiknsmnnczx6brsbppyljcs9hqckawk-gcc-12.3.0/include/c++/12
.3.0/bits/chrono.h:225:38
    #1 0x736d376b2b69 in std::enable_if<__is_duration<std::chrono::duration<long, std::ratio<1l, 1000000000l>>>::value, std::chr
ono::duration<long, std::ratio<1l, 1000000000l>>>::type std::chrono::duration_cast<std::chrono::duration<long, std::ratio<1l, 10
00000000l>>, long, std::ratio<1l, 1000l>>(std::chrono::duration<long, std::ratio<1l, 1000l>> const&) /nix/store/fdiknsmnnczx6brs
bppyljcs9hqckawk-gcc-12.3.0/include/c++/12.3.0/bits/chrono.h:270:9
    #2 0x736d376b2b69 in std::enable_if<__is_duration<std::chrono::duration<long, std::ratio<1l, 1000000000l>>>::value, std::chr
ono::duration<long, std::ratio<1l, 1000000000l>>>::type std::chrono::ceil<std::chrono::duration<long, std::ratio<1l, 1000000000l
>>, long, std::ratio<1l, 1000l>>(std::chrono::duration<long, std::ratio<1l, 1000l>> const&) /nix/store/fdiknsmnnczx6brsbppyljcs9
hqckawk-gcc-12.3.0/include/c++/12.3.0/bits/chrono.h:386:14
    #3 0x736d376b2b69 in std::cv_status std::condition_variable::wait_for<long, std::ratio<1l, 1000l>>(std::unique_lock<std::mut
ex>&, std::chrono::duration<long, std::ratio<1l, 1000l>> const&) /nix/store/fdiknsmnnczx6brsbppyljcs9hqckawk-gcc-12.3.0/include/
c++/12.3.0/condition_variable:164:6
    #4 0x736d376b1ee9 in std::cv_status nix::Sync<nix::ProgressBar::State, std::mutex>::Lock::wait_for<long, std::ratio<1l, 1000
l>>(std::condition_variable&, std::chrono::duration<long, std::ratio<1l, 1000l>> const&) /home/jade/lix/lix/src/libutil/sync.hh:
65:23
    #5 0x736d376b1ee9 in nix::ProgressBar::ProgressBar(bool)::'lambda'()::operator()() const /home/jade/lix/lix/src/libmain/prog
ress-bar.cc:99:27
    #6 0x736d36de25c2 in execute_native_thread_routine (/nix/store/a3zlvnswi1p8cg7i9w4lpnvaankc7dxx-gcc-12.3.0-lib/lib/libstdc++
.so.6+0xe05c2)
    #7 0x736d36b6b0e3 in start_thread (/nix/store/1zy01hjzwvvia6h9dq5xar88v77fgh9x-glibc-2.38-44/lib/libc.so.6+0x8b0e3) (BuildId
: 287831bffdbdde0ec25dbd021d12bdfc0ab9f5ff)
    #8 0x736d36bed5e3 in __clone (/nix/store/1zy01hjzwvvia6h9dq5xar88v77fgh9x-glibc-2.38-44/lib/libc.so.6+0x10d5e3) (BuildId: 28
7831bffdbdde0ec25dbd021d12bdfc0ab9f5ff)

SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /nix/store/fdiknsmnnczx6brsbppyljcs9hqckawk-gcc-12.3.0/include/c++/12.3.
0/bits/chrono.h:225:38 in

Change-Id: Ia0303242cdfd5d49385ae9e99718d709625a4633
---
 src/libmain/progress-bar.cc | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/libmain/progress-bar.cc b/src/libmain/progress-bar.cc
index 5c648ccf7..1a68daca2 100644
--- a/src/libmain/progress-bar.cc
+++ b/src/libmain/progress-bar.cc
@@ -12,6 +12,8 @@
 
 namespace nix {
 
+using namespace std::literals::chrono_literals;
+
 static std::string_view getS(const std::vector<Logger::Field> & fields, size_t n)
 {
     assert(n < fields.size());
@@ -33,6 +35,9 @@ static std::string_view storePathToName(std::string_view path)
     return i == std::string::npos ? base.substr(0, 0) : base.substr(i + 1);
 }
 
+// 100 years ought to be enough for anyone (yet sufficiently smaller than max() to not cause signed integer overflow).
+constexpr const auto A_LONG_TIME = std::chrono::duration_cast<std::chrono::milliseconds>(100 * 365 * 86400s);
+
 class ProgressBar : public Logger
 {
 private:
@@ -93,7 +98,7 @@ public:
         state_.lock()->active = isTTY;
         updateThread = std::thread([&]() {
             auto state(state_.lock());
-            auto nextWakeup = std::chrono::milliseconds::max();
+            auto nextWakeup = A_LONG_TIME;
             while (state->active) {
                 if (!state->haveUpdate)
                     state.wait_for(updateCV, nextWakeup);
@@ -350,7 +355,7 @@ public:
 
     std::chrono::milliseconds draw(State & state)
     {
-        auto nextWakeup = std::chrono::milliseconds::max();
+        auto nextWakeup = A_LONG_TIME;
 
         state.haveUpdate = false;
         if (state.paused || !state.active) return nextWakeup;