Nix/src/libutil/current-process.cc
Rebecca Turner 3a124d1e88
Increase stack size on macOS as well as Linux
The code works fine on macOS, but the default stack size we attempt to
set is larger than what my system will allow (Nix attempts to set the
stack size to 67108864, but the maximum allowed is 67092480), so I've
instead used the requested stack size or the maximum allowed, whichever
is smaller.

I've also added an error message if setting the stack size fails. It
looks like this:

> Failed to increase stack size from 8372224 to 67108864 (maximum
> allowed stack size: 67092480): Invalid argument
2024-01-26 09:40:41 -08:00

119 lines
2.7 KiB
C++

#include <algorithm>
#include <cstring>
#include "current-process.hh"
#include "namespaces.hh"
#include "util.hh"
#include "finally.hh"
#include "file-system.hh"
#include "processes.hh"
#include "signals.hh"
#ifdef __APPLE__
# include <mach-o/dyld.h>
#endif
#if __linux__
# include <mutex>
# include <sys/resource.h>
# include "cgroup.hh"
#endif
#include <sys/mount.h>
namespace nix {
unsigned int getMaxCPU()
{
#if __linux__
try {
auto cgroupFS = getCgroupFS();
if (!cgroupFS) return 0;
auto cgroups = getCgroups("/proc/self/cgroup");
auto cgroup = cgroups[""];
if (cgroup == "") return 0;
auto cpuFile = *cgroupFS + "/" + cgroup + "/cpu.max";
auto cpuMax = readFile(cpuFile);
auto cpuMaxParts = tokenizeString<std::vector<std::string>>(cpuMax, " \n");
auto quota = cpuMaxParts[0];
auto period = cpuMaxParts[1];
if (quota != "max")
return std::ceil(std::stoi(quota) / std::stof(period));
} catch (Error &) { ignoreException(lvlDebug); }
#endif
return 0;
}
//////////////////////////////////////////////////////////////////////
rlim_t savedStackSize = 0;
void setStackSize(rlim_t stackSize)
{
struct rlimit limit;
if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) {
savedStackSize = limit.rlim_cur;
limit.rlim_cur = std::min(stackSize, limit.rlim_max);
if (setrlimit(RLIMIT_STACK, &limit) != 0) {
logger->log(
lvlError,
hintfmt(
"Failed to increase stack size from %1% to %2% (maximum allowed stack size: %3%): %4%",
savedStackSize,
stackSize,
limit.rlim_max,
std::strerror(errno)
).str()
);
}
}
}
void restoreProcessContext(bool restoreMounts)
{
restoreSignals();
if (restoreMounts) {
restoreMountNamespace();
}
if (savedStackSize) {
struct rlimit limit;
if (getrlimit(RLIMIT_STACK, &limit) == 0) {
limit.rlim_cur = savedStackSize;
setrlimit(RLIMIT_STACK, &limit);
}
}
}
//////////////////////////////////////////////////////////////////////
std::optional<Path> getSelfExe()
{
static auto cached = []() -> std::optional<Path>
{
#if __linux__
return readLink("/proc/self/exe");
#elif __APPLE__
char buf[1024];
uint32_t size = sizeof(buf);
if (_NSGetExecutablePath(buf, &size) == 0)
return buf;
else
return std::nullopt;
#else
return std::nullopt;
#endif
}();
return cached;
}
}