nix-super/src/libutil/current-process.cc
John Ericson ac89bb064a Split up util.{hh,cc}
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.

This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.

Newly exposed functions to break cycles:

 - `restoreSignals`
 - `updateWindowSize`
2023-11-05 12:20:02 -05:00

110 lines
2.3 KiB
C++

#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;
}
//////////////////////////////////////////////////////////////////////
#if __linux__
rlim_t savedStackSize = 0;
#endif
void setStackSize(size_t stackSize)
{
#if __linux__
struct rlimit limit;
if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) {
savedStackSize = limit.rlim_cur;
limit.rlim_cur = stackSize;
setrlimit(RLIMIT_STACK, &limit);
}
#endif
}
void restoreProcessContext(bool restoreMounts)
{
restoreSignals();
if (restoreMounts) {
restoreMountNamespace();
}
#if __linux__
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__
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;
}
}