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minix3/servers/pm/signal.c

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/* This file handles signals, which are asynchronous events and are generally
* a messy and unpleasant business. Signals can be generated by the KILL
* system call, or from the keyboard (SIGINT) or from the clock (SIGALRM).
* In all cases control eventually passes to check_sig() to see which processes
* can be signaled. The actual signaling is done by sig_proc().
*
* The entry points into this file are:
* do_sigaction: perform the SIGACTION system call
* do_sigpending: perform the SIGPENDING system call
* do_sigprocmask: perform the SIGPROCMASK system call
* do_sigreturn: perform the SIGRETURN system call
* do_sigsuspend: perform the SIGSUSPEND system call
* do_kill: perform the KILL system call
* process_ksig: process a signal an behalf of the kernel
* sig_proc: interrupt or terminate a signaled process
* check_sig: check which processes to signal with sig_proc()
* check_pending: check if a pending signal can now be delivered
* restart_sigs: restart signal work after finishing a VFS call
*/
#include "pm.h"
#include <sys/stat.h>
#include <sys/ptrace.h>
#include <minix/callnr.h>
#include <minix/endpoint.h>
#include <minix/com.h>
#include <minix/vm.h>
#include <signal.h>
#include <sys/resource.h>
#include <assert.h>
#include "mproc.h"
static int unpause(struct mproc *rmp);
static int sig_send(struct mproc *rmp, int signo);
static void sig_proc_exit(struct mproc *rmp, int signo);
/*===========================================================================*
* do_sigaction *
*===========================================================================*/
int do_sigaction(void)
{
int r, sig_nr;
struct sigaction svec;
struct sigaction *svp;
assert(!(mp->mp_flags & (PROC_STOPPED | VFS_CALL | UNPAUSED)));
sig_nr = m_in.m_lc_pm_sig.nr;
if (sig_nr == SIGKILL) return(OK);
if (sig_nr < 1 || sig_nr >= _NSIG) return(EINVAL);
svp = &mp->mp_sigact[sig_nr];
if (m_in.m_lc_pm_sig.oact != 0) {
r = sys_datacopy(PM_PROC_NR,(vir_bytes) svp, who_e,
m_in.m_lc_pm_sig.oact, (phys_bytes) sizeof(svec));
if (r != OK) return(r);
}
if (m_in.m_lc_pm_sig.act == 0)
return(OK);
/* Read in the sigaction structure. */
r = sys_datacopy(who_e, m_in.m_lc_pm_sig.act, PM_PROC_NR, (vir_bytes) &svec,
(phys_bytes) sizeof(svec));
if (r != OK) return(r);
if (svec.sa_handler == SIG_IGN) {
sigaddset(&mp->mp_ignore, sig_nr);
sigdelset(&mp->mp_sigpending, sig_nr);
sigdelset(&mp->mp_ksigpending, sig_nr);
sigdelset(&mp->mp_catch, sig_nr);
} else if (svec.sa_handler == SIG_DFL) {
sigdelset(&mp->mp_ignore, sig_nr);
sigdelset(&mp->mp_catch, sig_nr);
} else {
sigdelset(&mp->mp_ignore, sig_nr);
sigaddset(&mp->mp_catch, sig_nr);
}
mp->mp_sigact[sig_nr].sa_handler = svec.sa_handler;
sigdelset(&svec.sa_mask, SIGKILL);
sigdelset(&svec.sa_mask, SIGSTOP);
mp->mp_sigact[sig_nr].sa_mask = svec.sa_mask;
mp->mp_sigact[sig_nr].sa_flags = svec.sa_flags;
mp->mp_sigreturn = m_in.m_lc_pm_sig.ret;
return(OK);
}
/*===========================================================================*
* do_sigpending *
*===========================================================================*/
int do_sigpending(void)
{
assert(!(mp->mp_flags & (PROC_STOPPED | VFS_CALL | UNPAUSED)));
mp->mp_reply.m_pm_lc_sigset.set = mp->mp_sigpending;
return OK;
}
/*===========================================================================*
* do_sigprocmask *
*===========================================================================*/
int do_sigprocmask(void)
{
/* Note that the library interface passes the actual mask in sigmask_set,
* not a pointer to the mask, in order to save a copy. Similarly,
* the old mask is placed in the return message which the library
* interface copies (if requested) to the user specified address.
*
* The library interface must set SIG_INQUIRE if the 'act' argument
* is NULL.
*
* KILL and STOP can't be masked.
*/
sigset_t set;
int i;
assert(!(mp->mp_flags & (PROC_STOPPED | VFS_CALL | UNPAUSED)));
set = m_in.m_lc_pm_sigset.set;
mp->mp_reply.m_pm_lc_sigset.set = mp->mp_sigmask;
switch (m_in.m_lc_pm_sigset.how) {
case SIG_BLOCK:
sigdelset(&set, SIGKILL);
sigdelset(&set, SIGSTOP);
for (i = 1; i < _NSIG; i++) {
if (sigismember(&set, i))
sigaddset(&mp->mp_sigmask, i);
}
break;
case SIG_UNBLOCK:
for (i = 1; i < _NSIG; i++) {
if (sigismember(&set, i))
sigdelset(&mp->mp_sigmask, i);
}
check_pending(mp);
break;
case SIG_SETMASK:
sigdelset(&set, SIGKILL);
sigdelset(&set, SIGSTOP);
mp->mp_sigmask = set;
check_pending(mp);
break;
case SIG_INQUIRE:
break;
default:
return(EINVAL);
break;
}
return OK;
}
/*===========================================================================*
* do_sigsuspend *
*===========================================================================*/
int do_sigsuspend(void)
{
assert(!(mp->mp_flags & (PROC_STOPPED | VFS_CALL | UNPAUSED)));
mp->mp_sigmask2 = mp->mp_sigmask; /* save the old mask */
mp->mp_sigmask = m_in.m_lc_pm_sigset.set;
sigdelset(&mp->mp_sigmask, SIGKILL);
sigdelset(&mp->mp_sigmask, SIGSTOP);
mp->mp_flags |= SIGSUSPENDED;
check_pending(mp);
return(SUSPEND);
}
/*===========================================================================*
* do_sigreturn *
*===========================================================================*/
int do_sigreturn(void)
{
/* A user signal handler is done. Restore context and check for
* pending unblocked signals.
*/
int r;
assert(!(mp->mp_flags & (PROC_STOPPED | VFS_CALL | UNPAUSED)));
mp->mp_sigmask = m_in.m_lc_pm_sigset.set;
sigdelset(&mp->mp_sigmask, SIGKILL);
sigdelset(&mp->mp_sigmask, SIGSTOP);
r = sys_sigreturn(who_e, (struct sigmsg *)m_in.m_lc_pm_sigset.ctx);
check_pending(mp);
return(r);
}
/*===========================================================================*
* do_kill *
*===========================================================================*/
int do_kill(void)
{
/* Perform the kill(pid, signo) system call. */
return check_sig(m_in.m_lc_pm_sig.pid, m_in.m_lc_pm_sig.nr, FALSE /* ksig */);
}
/*===========================================================================*
* do_srv_kill *
*===========================================================================*/
int do_srv_kill(void)
{
/* Perform the srv_kill(pid, signo) system call. */
/* Only RS is allowed to use srv_kill. */
if (mp->mp_endpoint != RS_PROC_NR)
return EPERM;
/* Pretend the signal comes from the kernel when RS wants to deliver a signal
* to a system process. RS sends a SIGKILL when it wants to perform cleanup.
* In that case, ksig == TRUE forces PM to exit the process immediately.
*/
return check_sig(m_in.m_rs_pm_srv_kill.pid, m_in.m_rs_pm_srv_kill.nr,
TRUE /* ksig */);
}
/*===========================================================================*
* stop_proc *
*===========================================================================*/
static int stop_proc(struct mproc *rmp, int may_delay)
{
/* Try to stop the given process in the kernel. If successful, mark the process
* as stopped and return TRUE. If the process is still busy sending a message,
* the behavior depends on the 'may_delay' parameter. If set, the process will
* be marked as having a delay call pending, and the function returns FALSE. If
* not set, the caller already knows that the process has no delay call, and PM
* will panic.
*/
int r;
assert(!(rmp->mp_flags & (PROC_STOPPED | DELAY_CALL | UNPAUSED)));
r = sys_delay_stop(rmp->mp_endpoint);
/* If the process is still busy sending a message, the kernel will give us
* EBUSY now and send a SIGSNDELAY to the process as soon as sending is done.
*/
switch (r) {
case OK:
rmp->mp_flags |= PROC_STOPPED;
return TRUE;
case EBUSY:
if (!may_delay)
panic("stop_proc: unexpected delay call");
rmp->mp_flags |= DELAY_CALL;
return FALSE;
default:
panic("sys_delay_stop failed: %d", r);
}
}
/*===========================================================================*
* try_resume_proc *
*===========================================================================*/
static void try_resume_proc(struct mproc *rmp)
{
/* Resume the given process if possible. */
int r;
assert(rmp->mp_flags & PROC_STOPPED);
/* If the process is blocked on a VFS call, do not resume it now. Most likely * it will be unpausing, in which case the process must remain stopped.
* Otherwise, it will still be resumed once the VFS call returns. If the
* process has died, do not resume it either.
*/
if (rmp->mp_flags & (VFS_CALL | EXITING))
return;
if ((r = sys_resume(rmp->mp_endpoint)) != OK)
panic("sys_resume failed: %d", r);
/* Also unset the unpaused flag. We can safely assume that a stopped process
* need only be unpaused once, but once it is resumed, all bets are off.
*/
rmp->mp_flags &= ~(PROC_STOPPED | UNPAUSED);
}
/*===========================================================================*
* process_ksig *
*===========================================================================*/
int process_ksig(endpoint_t proc_nr_e, int signo)
{
register struct mproc *rmp;
int proc_nr;
pid_t proc_id, id;
if(pm_isokendpt(proc_nr_e, &proc_nr) != OK) {
printf("PM: process_ksig: %d?? not ok\n", proc_nr_e);
return EDEADEPT; /* process is gone. */
}
rmp = &mproc[proc_nr];
if ((rmp->mp_flags & (IN_USE | EXITING)) != IN_USE) {
#if 0
printf("PM: process_ksig: %d?? exiting / not in use\n", proc_nr_e);
#endif
return EDEADEPT; /* process is gone. */
}
proc_id = rmp->mp_pid;
mp = &mproc[0]; /* pretend signals are from PM */
mp->mp_procgrp = rmp->mp_procgrp; /* get process group right */
/* For SIGVTALRM and SIGPROF, see if we need to restart a
* virtual timer. For SIGINT, SIGINFO, SIGWINCH and SIGQUIT, use proc_id 0
* to indicate a broadcast to the recipient's process group. For
* SIGKILL, use proc_id -1 to indicate a systemwide broadcast.
*/
switch (signo) {
case SIGINT:
case SIGQUIT:
case SIGWINCH:
case SIGINFO:
id = 0; break; /* broadcast to process group */
case SIGVTALRM:
case SIGPROF:
check_vtimer(proc_nr, signo);
/* fall-through */
default:
id = proc_id;
break;
}
check_sig(id, signo, TRUE /* ksig */);
/* If SIGSNDELAY is set, an earlier sys_stop() failed because the process was
* still sending, and the kernel hereby tells us that the process is now done
* with that. We can now try to resume what we planned to do in the first
* place: set up a signal handler. However, the process's message may have
* been a call to PM, in which case the process may have changed any of its
* signal settings. The process may also have forked, exited etcetera.
*/
if (signo == SIGSNDELAY && (rmp->mp_flags & DELAY_CALL)) {
/* When getting SIGSNDELAY, the process is stopped at least until the
* receipt of the SIGSNDELAY signal is acknowledged to the kernel. The
* process is not stopped on PROC_STOP in the kernel. However, now that
* there is no longer a delay call, stop_proc() is guaranteed to
* succeed immediately.
*/
rmp->mp_flags &= ~DELAY_CALL;
assert(!(rmp->mp_flags & PROC_STOPPED));
/* If the delay call was to PM, it may have resulted in a VFS call. In
* that case, we must wait with further signal processing until VFS has
* replied. Stop the process.
*/
if (rmp->mp_flags & VFS_CALL) {
stop_proc(rmp, FALSE /*may_delay*/);
return OK;
}
/* Process as many normal signals as possible. */
check_pending(rmp);
assert(!(rmp->mp_flags & DELAY_CALL));
}
/* See if the process is still alive */
if ((mproc[proc_nr].mp_flags & (IN_USE | EXITING)) == IN_USE) {
return OK; /* signal has been delivered */
}
else {
return EDEADEPT; /* process is gone */
}
}
/*===========================================================================*
* sig_proc *
*===========================================================================*/
void sig_proc(rmp, signo, trace, ksig)
register struct mproc *rmp; /* pointer to the process to be signaled */
int signo; /* signal to send to process (1 to _NSIG-1) */
int trace; /* pass signal to tracer first? */
int ksig; /* non-zero means signal comes from kernel */
{
/* Send a signal to a process. Check to see if the signal is to be caught,
* ignored, tranformed into a message (for system processes) or blocked.
* - If the signal is to be transformed into a message, request the KERNEL to
* send the target process a system notification with the pending signal as an
* argument.
* - If the signal is to be caught, request the KERNEL to push a sigcontext
* structure and a sigframe structure onto the catcher's stack. Also, KERNEL
* will reset the program counter and stack pointer, so that when the process
* next runs, it will be executing the signal handler. When the signal handler
* returns, sigreturn(2) will be called. Then KERNEL will restore the signal
* context from the sigcontext structure.
* If there is insufficient stack space, kill the process.
*/
int slot, badignore;
slot = (int) (rmp - mproc);
if ((rmp->mp_flags & (IN_USE | EXITING)) != IN_USE) {
panic("PM: signal %d sent to exiting process %d\n", signo, slot);
}
if (trace == TRUE && rmp->mp_tracer != NO_TRACER && signo != SIGKILL) {
/* Signal should be passed to the debugger first.
* This happens before any checks on block/ignore masks; otherwise,
* the process itself could block/ignore debugger signals.
*/
sigaddset(&rmp->mp_sigtrace, signo);
if (!(rmp->mp_flags & TRACE_STOPPED))
trace_stop(rmp, signo); /* a signal causes it to stop */
return;
}
if (rmp->mp_flags & VFS_CALL) {
sigaddset(&rmp->mp_sigpending, signo);
if(ksig)
sigaddset(&rmp->mp_ksigpending, signo);
/* Process the signal once VFS replies. Stop the process in the
* meantime, so that it cannot make another call after the VFS reply
* comes in but before we look at its signals again. Since we always
* stop the process to deliver signals during a VFS call, the
* PROC_STOPPED flag doubles as an indicator in restart_sigs() that
* signals must be rechecked after a VFS reply comes in.
*/
if (!(rmp->mp_flags & (PROC_STOPPED | DELAY_CALL))) {
/* If a VFS call is ongoing and the process is not yet stopped,
* the process must have made a call to PM. Therefore, there
* can be no delay calls in this case.
*/
stop_proc(rmp, FALSE /*delay_call*/);
}
return;
}
/* Handle system signals for system processes first. */
if(rmp->mp_flags & PRIV_PROC) {
/* Always skip signals for PM (only necessary when broadcasting). */
if(rmp->mp_endpoint == PM_PROC_NR) {
return;
}
/* System signals have always to go through the kernel first to let it
* pick the right signal manager. If PM is the assigned signal manager,
* the signal will come back and will actually be processed.
*/
if(!ksig) {
sys_kill(rmp->mp_endpoint, signo);
return;
}
/* Print stacktrace if necessary. */
if(SIGS_IS_STACKTRACE(signo)) {
sys_diagctl_stacktrace(rmp->mp_endpoint);
}
if(!SIGS_IS_TERMINATION(signo)) {
/* Translate every non-termination sys signal into a message. */
message m;
m.m_type = SIGS_SIGNAL_RECEIVED;
m.m_pm_lsys_sigs_signal.num = signo;
asynsend3(rmp->mp_endpoint, &m, AMF_NOREPLY);
}
else {
/* Exit the process in case of termination system signal. */
sig_proc_exit(rmp, signo);
}
return;
}
/* Handle user processes now. See if the signal cannot be safely ignored. */
badignore = ksig && sigismember(&noign_sset, signo) && (
sigismember(&rmp->mp_ignore, signo) ||
sigismember(&rmp->mp_sigmask, signo));
if (!badignore && sigismember(&rmp->mp_ignore, signo)) {
/* Signal should be ignored. */
return;
}
if (!badignore && sigismember(&rmp->mp_sigmask, signo)) {
/* Signal should be blocked. */
sigaddset(&rmp->mp_sigpending, signo);
if(ksig)
sigaddset(&rmp->mp_ksigpending, signo);
return;
}
if ((rmp->mp_flags & TRACE_STOPPED) && signo != SIGKILL) {
/* If the process is stopped for a debugger, do not deliver any signals
* (except SIGKILL) in order not to confuse the debugger. The signals
* will be delivered using the check_pending() calls in do_trace().
*/
sigaddset(&rmp->mp_sigpending, signo);
if(ksig)
sigaddset(&rmp->mp_ksigpending, signo);
return;
}
if (!badignore && sigismember(&rmp->mp_catch, signo)) {
/* Signal is caught. First interrupt the process's current call, if
* applicable. This may involve a roundtrip to VFS, in which case we'll
* have to check back later.
*/
if (!unpause(rmp)) {
/* not yet unpaused; continue later */
sigaddset(&rmp->mp_sigpending, signo);
if(ksig)
sigaddset(&rmp->mp_ksigpending, signo);
return;
}
/* Then send the actual signal to the process, by setting up a signal
* handler.
*/
if (sig_send(rmp, signo))
return;
/* We were unable to spawn a signal handler. Kill the process. */
printf("PM: %d can't catch signal %d - killing\n",
rmp->mp_pid, signo);
}
else if (!badignore && sigismember(&ign_sset, signo)) {
/* Signal defaults to being ignored. */
return;
}
/* Terminate process */
sig_proc_exit(rmp, signo);
}
/*===========================================================================*
* sig_proc_exit *
*===========================================================================*/
static void sig_proc_exit(rmp, signo)
struct mproc *rmp; /* process that must exit */
int signo; /* signal that caused termination */
{
rmp->mp_sigstatus = (char) signo;
if (sigismember(&core_sset, signo)) {
if(!(rmp->mp_flags & PRIV_PROC)) {
printf("PM: coredump signal %d for %d / %s\n", signo,
rmp->mp_pid, rmp->mp_name);
sys_diagctl_stacktrace(rmp->mp_endpoint);
}
exit_proc(rmp, 0, TRUE /*dump_core*/);
}
else {
exit_proc(rmp, 0, FALSE /*dump_core*/);
}
}
/*===========================================================================*
* check_sig *
*===========================================================================*/
int check_sig(proc_id, signo, ksig)
pid_t proc_id; /* pid of proc to sig, or 0 or -1, or -pgrp */
int signo; /* signal to send to process (0 to _NSIG-1) */
int ksig; /* non-zero means signal comes from kernel */
{
/* Check to see if it is possible to send a signal. The signal may have to be
* sent to a group of processes. This routine is invoked by the KILL system
* call, and also when the kernel catches a DEL or other signal.
*/
register struct mproc *rmp;
int count; /* count # of signals sent */
int error_code;
if (signo < 0 || signo >= _NSIG) return(EINVAL);
/* Return EINVAL for attempts to send SIGKILL to INIT alone. */
if (proc_id == INIT_PID && signo == SIGKILL) return(EINVAL);
/* Signal RS first when broadcasting SIGTERM. */
if (proc_id == -1 && signo == SIGTERM)
sys_kill(RS_PROC_NR, signo);
/* Search the proc table for processes to signal. Start from the end of the
* table to analyze core system processes at the end when broadcasting.
* (See forkexit.c about pid magic.)
*/
count = 0;
error_code = ESRCH;
for (rmp = &mproc[NR_PROCS-1]; rmp >= &mproc[0]; rmp--) {
if (!(rmp->mp_flags & IN_USE)) continue;
/* Check for selection. */
if (proc_id > 0 && proc_id != rmp->mp_pid) continue;
if (proc_id == 0 && mp->mp_procgrp != rmp->mp_procgrp) continue;
if (proc_id == -1 && rmp->mp_pid <= INIT_PID) continue;
if (proc_id < -1 && rmp->mp_procgrp != -proc_id) continue;
/* Do not kill servers and drivers when broadcasting SIGKILL. */
if (proc_id == -1 && signo == SIGKILL &&
(rmp->mp_flags & PRIV_PROC)) continue;
/* Skip VM entirely as it might lead to a deadlock with its signal
* manager if the manager page faults at the same time.
*/
if (rmp->mp_endpoint == VM_PROC_NR) continue;
/* Disallow lethal signals sent by user processes to sys processes. */
if (!ksig && SIGS_IS_LETHAL(signo) && (rmp->mp_flags & PRIV_PROC)) {
error_code = EPERM;
continue;
}
/* Check for permission. */
if (mp->mp_effuid != SUPER_USER
&& mp->mp_realuid != rmp->mp_realuid
&& mp->mp_effuid != rmp->mp_realuid
&& mp->mp_realuid != rmp->mp_effuid
&& mp->mp_effuid != rmp->mp_effuid) {
error_code = EPERM;
continue;
}
count++;
if (signo == 0 || (rmp->mp_flags & EXITING)) continue;
/* 'sig_proc' will handle the disposition of the signal. The
* signal may be caught, blocked, ignored, or cause process
* termination, possibly with core dump.
*/
sig_proc(rmp, signo, TRUE /*trace*/, ksig);
if (proc_id > 0) break; /* only one process being signaled */
}
/* If the calling process has killed itself, don't reply. */
if ((mp->mp_flags & (IN_USE | EXITING)) != IN_USE) return(SUSPEND);
return(count > 0 ? OK : error_code);
}
/*===========================================================================*
* check_pending *
*===========================================================================*/
void check_pending(rmp)
register struct mproc *rmp;
{
/* Check to see if any pending signals have been unblocked. Deliver as many
* of them as we can, until we have to wait for a reply from VFS first.
*
* There are several places in this file where the signal mask is
* changed. At each such place, check_pending() should be called to
* check for newly unblocked signals.
*/
int i;
int ksig;
for (i = 1; i < _NSIG; i++) {
if (sigismember(&rmp->mp_sigpending, i) &&
!sigismember(&rmp->mp_sigmask, i)) {
ksig = sigismember(&rmp->mp_ksigpending, i);
sigdelset(&rmp->mp_sigpending, i);
sigdelset(&rmp->mp_ksigpending, i);
sig_proc(rmp, i, FALSE /*trace*/, ksig);
if (rmp->mp_flags & VFS_CALL) {
/* Signals must be rechecked upon return from the new
* VFS call, unless the process was killed. In both
* cases, the process is stopped.
*/
assert(rmp->mp_flags & PROC_STOPPED);
break;
}
}
}
}
/*===========================================================================*
* restart_sigs *
*===========================================================================*/
void restart_sigs(rmp)
struct mproc *rmp;
{
/* VFS has replied to a request from us; do signal-related work.
*/
if (rmp->mp_flags & (VFS_CALL | EXITING)) return;
if (rmp->mp_flags & TRACE_EXIT) {
/* Tracer requested exit with specific exit value */
exit_proc(rmp, rmp->mp_exitstatus, FALSE /*dump_core*/);
}
else if (rmp->mp_flags & PROC_STOPPED) {
/* If a signal arrives while we are performing a VFS call, the process
* will always be stopped immediately. Thus, if the process is stopped
* once the reply from VFS arrives, we might have to check signals.
*/
assert(!(rmp->mp_flags & DELAY_CALL));
/* We saved signal(s) for after finishing a VFS call. Deal with this.
* PROC_STOPPED remains set to indicate the process is still stopped.
*/
check_pending(rmp);
/* Resume the process now, unless there is a reason not to. */
try_resume_proc(rmp);
}
}
/*===========================================================================*
* unpause *
*===========================================================================*/
static int unpause(rmp)
struct mproc *rmp; /* which process */
{
/* A signal is to be sent to a process. If that process is hanging on a
* system call, the system call must be terminated with EINTR. First check if
* the process is hanging on an PM call. If not, tell VFS, so it can check for
* interruptible calls such as READs and WRITEs from pipes, ttys and the like.
*/
message m;
assert(!(rmp->mp_flags & VFS_CALL));
/* If the UNPAUSED flag is set, VFS replied to an earlier unpause request. */
if (rmp->mp_flags & UNPAUSED) {
assert((rmp->mp_flags & (DELAY_CALL | PROC_STOPPED)) == PROC_STOPPED);
return TRUE;
}
/* If the process is already stopping, don't do anything now. */
if (rmp->mp_flags & DELAY_CALL)
return FALSE;
/* Check to see if process is hanging on a WAIT or SIGSUSPEND call. */
if (rmp->mp_flags & (WAITING | SIGSUSPENDED)) {
/* Stop the process from running. Do not interrupt the actual call yet.
* sig_send() will interrupt the call and resume the process afterward.
* No delay calls: we know for a fact that the process called us.
*/
stop_proc(rmp, FALSE /*may_delay*/);
return TRUE;
}
/* Not paused in PM. Let VFS try to unpause the process. The process needs to
* be stopped for this. If it is not already stopped, try to stop it now. If
* that does not succeed immediately, postpone signal delivery.
*/
if (!(rmp->mp_flags & PROC_STOPPED) && !stop_proc(rmp, TRUE /*may_delay*/))
return FALSE;
memset(&m, 0, sizeof(m));
m.m_type = VFS_PM_UNPAUSE;
m.VFS_PM_ENDPT = rmp->mp_endpoint;
tell_vfs(rmp, &m);
/* Also tell VM. */
vm_notify_sig_wrapper(rmp->mp_endpoint);
return FALSE;
}
/*===========================================================================*
* sig_send *
*===========================================================================*/
static int sig_send(rmp, signo)
struct mproc *rmp; /* what process to spawn a signal handler in */
int signo; /* signal to send to process (1 to _NSIG-1) */
{
/* The process is supposed to catch this signal. Spawn a signal handler.
* Return TRUE if this succeeded, FALSE otherwise.
*/
struct sigmsg sigmsg;
int i, r, sigflags, slot;
assert(rmp->mp_flags & PROC_STOPPED);
sigflags = rmp->mp_sigact[signo].sa_flags;
slot = (int) (rmp - mproc);
if (rmp->mp_flags & SIGSUSPENDED)
sigmsg.sm_mask = rmp->mp_sigmask2;
else
sigmsg.sm_mask = rmp->mp_sigmask;
sigmsg.sm_signo = signo;
sigmsg.sm_sighandler =
(vir_bytes) rmp->mp_sigact[signo].sa_handler;
sigmsg.sm_sigreturn = rmp->mp_sigreturn;
for (i = 1; i < _NSIG; i++) {
if (sigismember(&rmp->mp_sigact[signo].sa_mask, i))
sigaddset(&rmp->mp_sigmask, i);
}
if (sigflags & SA_NODEFER)
sigdelset(&rmp->mp_sigmask, signo);
else
sigaddset(&rmp->mp_sigmask, signo);
if (sigflags & SA_RESETHAND) {
sigdelset(&rmp->mp_catch, signo);
rmp->mp_sigact[signo].sa_handler = SIG_DFL;
}
sigdelset(&rmp->mp_sigpending, signo);
sigdelset(&rmp->mp_ksigpending, signo);
/* Ask the kernel to deliver the signal */
r = sys_sigsend(rmp->mp_endpoint, &sigmsg);
/* sys_sigsend can fail legitimately with EFAULT or ENOMEM if the process
* memory can't accommodate the signal handler. The target process will be
* killed in that case, so do not bother interrupting or resuming it.
*/
if(r == EFAULT || r == ENOMEM) {
return(FALSE);
}
/* Other errors are unexpected pm/kernel discrepancies. */
if (r != OK) {
panic("sys_sigsend failed: %d", r);
}
/* Was the process suspended in PM? Then interrupt the blocking call. */
if (rmp->mp_flags & (WAITING | SIGSUSPENDED)) {
rmp->mp_flags &= ~(WAITING | SIGSUSPENDED);
reply(slot, EINTR);
/* The process must just have been stopped by unpause(), which means
* that the UNPAUSE flag is not set.
*/
assert(!(rmp->mp_flags & UNPAUSED));
try_resume_proc(rmp);
assert(!(rmp->mp_flags & PROC_STOPPED));
} else {
/* If the process was not suspended in PM, VFS must first have
* confirmed that it has tried to unsuspend any blocking call. Thus, we
* got here from restart_sigs() as part of handling PM_UNPAUSE_REPLY,
* and restart_sigs() will resume the process later.
*/
assert(rmp->mp_flags & UNPAUSED);
}
return(TRUE);
}
/*===========================================================================*
* vm_notify_sig_wrapper *
*===========================================================================*/
void vm_notify_sig_wrapper(endpoint_t ep)
{
/* get IPC's endpoint,
* the reason that we directly get the endpoint
* instead of from DS server is that otherwise
* it will cause deadlock between PM, VM and DS.
*/
struct mproc *rmp;
endpoint_t ipc_ep = 0;
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++) {
if (!(rmp->mp_flags & IN_USE))
continue;
if (!strcmp(rmp->mp_name, "ipc")) {
ipc_ep = rmp->mp_endpoint;
vm_notify_sig(ep, ipc_ep);
return;
}
}
}
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