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syscall-emul: Add the tgkill system call

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This changeset adds support to kill a thread group by calling
the tgkill system call. The functionality is needed in some
pthread applications.

Change-Id: I0413a3331be69b74dfab30de95384113ec4efb63
Reviewed-on: https://gem5-review.googlesource.com/2268
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Michael LeBeane <Michael.Lebeane@amd.com>
This commit is contained in:
Brandon Potter
2017-03-01 14:34:11 -06:00
parent 8b85f950e5
commit 6f7bf1b11f
2 changed files with 51 additions and 2 deletions
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49
src/sim/syscall_emul.hh
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@@ -1973,5 +1973,54 @@ timeFunc(SyscallDesc *desc, int callnum, Process *process, ThreadContext *tc)
return sec;
}
template <class OS>
SyscallReturn
tgkillFunc(SyscallDesc *desc, int num, Process *process, ThreadContext *tc)
{
int index = 0;
int tgid = process->getSyscallArg(tc, index);
int tid = process->getSyscallArg(tc, index);
int sig = process->getSyscallArg(tc, index);
/**
* This system call is intended to allow killing a specific thread
* within an arbitrary thread group if sanctioned with permission checks.
* It's usually true that threads share the termination signal as pointed
* out by the pthread_kill man page and this seems to be the intended
* usage. Due to this being an emulated environment, assume the following:
* Threads are allowed to call tgkill because the EUID for all threads
* should be the same. There is no signal handling mechanism for kernel
* registration of signal handlers since signals are poorly supported in
* emulation mode. Since signal handlers cannot be registered, all
* threads within in a thread group must share the termination signal.
* We never exhaust PIDs so there's no chance of finding the wrong one
* due to PID rollover.
*/
System *sys = tc->getSystemPtr();
Process *tgt_proc = nullptr;
for (int i = 0; i < sys->numContexts(); i++) {
Process *temp = sys->threadContexts[i]->getProcessPtr();
if (temp->pid() == tid) {
tgt_proc = temp;
break;
}
}
if (sig != 0 || sig != OS::TGT_SIGABRT)
return -EINVAL;
if (tgt_proc == nullptr)
return -ESRCH;
if (tgid != -1 && tgt_proc->tgid() != tgid)
return -ESRCH;
if (sig == OS::TGT_SIGABRT)
exitGroupFunc(desc, 252, process, tc);
return 0;
}
#endif // __SIM_SYSCALL_EMUL_HH__