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Use vfork

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This commit is contained in:
Eelco Dolstra 2014-12-10 16:35:42 +01:00
parent b5ed5b6e66
commit 0e8fc118b3
3 changed files with 39 additions and 11 deletions
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31
src/libutil/util.cc
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@ -863,31 +863,46 @@ void killUser(uid_t uid)
//////////////////////////////////////////////////////////////////////
pid_t startProcess(std::function<void()> fun,
bool dieWithParent, const string & errorPrefix, bool runExitHandlers)
/* Wrapper around vfork to prevent the child process from clobbering
the caller's stack frame in the parent. */
static pid_t doFork(bool allowVfork, std::function<void()> fun) __attribute__((noinline));
static pid_t doFork(bool allowVfork, std::function<void()> fun)
{
#ifdef __linux__
pid_t pid = allowVfork ? vfork() : fork();
#else
pid_t pid = fork();
if (pid == -1) throw SysError("unable to fork");
#endif
if (pid != 0) return pid;
fun();
abort();
}
if (pid == 0) {
pid_t startProcess(std::function<void()> fun, const ProcessOptions & options)
{
auto wrapper = [&]() {
_writeToStderr = 0;
try {
#if __linux__
if (dieWithParent && prctl(PR_SET_PDEATHSIG, SIGKILL) == -1)
if (options.dieWithParent && prctl(PR_SET_PDEATHSIG, SIGKILL) == -1)
throw SysError("setting death signal");
#endif
restoreAffinity();
fun();
} catch (std::exception & e) {
try {
std::cerr << errorPrefix << e.what() << "\n";
std::cerr << options.errorPrefix << e.what() << "\n";
} catch (...) { }
} catch (...) { }
if (runExitHandlers)
if (options.runExitHandlers)
exit(1);
else
_exit(1);
}
};
pid_t pid = doFork(options.allowVfork, wrapper);
if (pid == -1) throw SysError("unable to fork");
return pid;
}