nix-super/src/libstore/build/hook-instance.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

88 lines
2.3 KiB
C++

#include "globals.hh"
#include "hook-instance.hh"
#include "file-system.hh"
#include "child.hh"
namespace nix {
HookInstance::HookInstance()
{
debug("starting build hook '%s'", concatStringsSep(" ", settings.buildHook.get()));
auto buildHookArgs = settings.buildHook.get();
if (buildHookArgs.empty())
throw Error("'build-hook' setting is empty");
auto buildHook = canonPath(buildHookArgs.front());
buildHookArgs.pop_front();
Strings args;
args.push_back(std::string(baseNameOf(buildHook)));
for (auto & arg : buildHookArgs)
args.push_back(arg);
args.push_back(std::to_string(verbosity));
/* Create a pipe to get the output of the child. */
fromHook.create();
/* Create the communication pipes. */
toHook.create();
/* Create a pipe to get the output of the builder. */
builderOut.create();
/* Fork the hook. */
pid = startProcess([&]() {
if (dup2(fromHook.writeSide.get(), STDERR_FILENO) == -1)
throw SysError("cannot pipe standard error into log file");
commonChildInit();
if (chdir("/") == -1) throw SysError("changing into /");
/* Dup the communication pipes. */
if (dup2(toHook.readSide.get(), STDIN_FILENO) == -1)
throw SysError("dupping to-hook read side");
/* Use fd 4 for the builder's stdout/stderr. */
if (dup2(builderOut.writeSide.get(), 4) == -1)
throw SysError("dupping builder's stdout/stderr");
/* Hack: pass the read side of that fd to allow build-remote
to read SSH error messages. */
if (dup2(builderOut.readSide.get(), 5) == -1)
throw SysError("dupping builder's stdout/stderr");
execv(buildHook.c_str(), stringsToCharPtrs(args).data());
throw SysError("executing '%s'", buildHook);
});
pid.setSeparatePG(true);
fromHook.writeSide = -1;
toHook.readSide = -1;
sink = FdSink(toHook.writeSide.get());
std::map<std::string, Config::SettingInfo> settings;
globalConfig.getSettings(settings);
for (auto & setting : settings)
sink << 1 << setting.first << setting.second.value;
sink << 0;
}
HookInstance::~HookInstance()
{
try {
toHook.writeSide = -1;
if (pid != -1) pid.kill();
} catch (...) {
ignoreException();
}
}
}