nix-super/src/libutil/current-process.cc
2024-09-04 19:10:31 +00:00

152 lines
3.7 KiB
C++

#include <algorithm>
#include <cstring>
#include "current-process.hh"
#include "util.hh"
#include "finally.hh"
#include "file-system.hh"
#include "processes.hh"
#include "signals.hh"
#include <math.h>
#ifdef __APPLE__
# include <mach-o/dyld.h>
#endif
#if __linux__
# include <mutex>
# include "cgroup.hh"
# include "namespaces.hh"
#endif
#ifndef _WIN32
# include <sys/resource.h>
#endif
namespace nix {
unsigned int getMaxCPU()
{
#if __linux__
try {
auto cgroupFS = getCgroupFS();
if (!cgroupFS) return 0;
auto cpuFile = *cgroupFS + "/" + getCurrentCgroup() + "/cpu.max";
auto cpuMax = readFile(cpuFile);
auto cpuMaxParts = tokenizeString<std::vector<std::string>>(cpuMax, " \n");
if (cpuMaxParts.size() != 2) {
return 0;
}
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;
}
//////////////////////////////////////////////////////////////////////
size_t savedStackSize = 0;
void setStackSize(size_t stackSize)
{
#ifndef _WIN32
struct rlimit limit;
if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) {
savedStackSize = limit.rlim_cur;
limit.rlim_cur = std::min(static_cast<rlim_t>(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()
);
}
}
#else
ULONG_PTR stackLow, stackHigh;
GetCurrentThreadStackLimits(&stackLow, &stackHigh);
ULONG maxStackSize = stackHigh - stackLow;
ULONG currStackSize = 0;
// This retrieves the current promised stack size
SetThreadStackGuarantee(&currStackSize);
if (currStackSize < stackSize) {
savedStackSize = currStackSize;
ULONG newStackSize = std::min(static_cast<ULONG>(stackSize), maxStackSize);
if (SetThreadStackGuarantee(&newStackSize) == 0) {
logger->log(
lvlError,
HintFmt(
"Failed to increase stack size from %1% to %2% (maximum allowed stack size: %3%): %4%",
savedStackSize,
stackSize,
maxStackSize,
std::to_string(GetLastError())
).str()
);
}
}
#endif
}
void restoreProcessContext(bool restoreMounts)
{
#ifndef _WIN32
unix::restoreSignals();
#endif
if (restoreMounts) {
#if __linux__
restoreMountNamespace();
#endif
}
#ifndef _WIN32
if (savedStackSize) {
struct rlimit limit;
if (getrlimit(RLIMIT_STACK, &limit) == 0) {
limit.rlim_cur = savedStackSize;
setrlimit(RLIMIT_STACK, &limit);
}
}
#endif
}
//////////////////////////////////////////////////////////////////////
std::optional<Path> getSelfExe()
{
static auto cached = []() -> std::optional<Path>
{
#if __linux__ || __GNU__
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;
}
}