hurd: implement SA_SIGINFO signal handlers.

SA_SIGINFO is actually just another way of expressing what we were
already passing over with struct sigcontext. This just introduces the
SIGINFO interface and fixes the posix values when that interface is
requested by the application.

1 files changed, 114 insertions, 11 deletions

diff --git a/sysdeps/mach/hurd/i386/trampoline.c b/sysdeps/mach/hurd/i386/trampoline.c
index 8c7976919c..4a9cab1332 100644
--- a/sysdeps/mach/hurd/i386/trampoline.c
+++ b/sysdeps/mach/hurd/i386/trampoline.c
@@ -19,13 +19,66 @@
 #include <hurd/signal.h>
 #include <hurd/userlink.h>
 #include <thread_state.h>
+#include <mach/exception.h>
 #include <mach/machine/eflags.h>
 #include <assert.h>
 #include <errno.h>
 #include "hurdfault.h"
 #include <intr-msg.h>
+#include <sys/ucontext.h>
 
 
+/* Fill in a siginfo_t structure for SA_SIGINFO-enabled handlers.  */
+static void fill_siginfo (siginfo_t *si, int signo,
+			  const struct hurd_signal_detail *detail,
+			  const struct machine_thread_all_state *state)
+{
+  si->si_signo = signo;
+  si->si_errno = detail->error;
+  si->si_code = detail->code;
+
+  /* XXX We would need a protocol change for sig_post to include
+   * this information.  */
+  si->si_pid = -1;
+  si->si_uid = -1;
+
+  /* Address of the faulting instruction or memory access.  */
+  if (detail->exc == EXC_BAD_ACCESS)
+    si->si_addr = (void *) detail->exc_subcode;
+  else
+    si->si_addr = (void *) state->basic.eip;
+
+  /* XXX On SIGCHLD, this should be the exit status of the child
+   * process.  We would need a protocol change for the proc server
+   * to send this information along with the signal.  */
+  si->si_status = 0;
+
+  si->si_band = 0;              /* SIGPOLL is not supported yet.  */
+  si->si_value.sival_int = 0;   /* sigqueue() is not supported yet.  */
+}
+
+/* Fill in a ucontext_t structure SA_SIGINFO-enabled handlers.  */
+static void fill_ucontext (ucontext_t *uc, const struct sigcontext *sc)
+{
+  uc->uc_flags = 0;
+  uc->uc_link = NULL;
+  uc->uc_sigmask = sc->sc_mask;
+  uc->uc_stack.ss_sp = (__ptr_t) sc->sc_esp;
+  uc->uc_stack.ss_size = 0;
+  uc->uc_stack.ss_flags = 0;
+
+  /* Registers.  */
+  memcpy (&uc->uc_mcontext.gregs[REG_GS], &sc->sc_gs,
+	  (REG_TRAPNO - REG_GS) * sizeof (int));
+  uc->uc_mcontext.gregs[REG_TRAPNO] = 0;
+  uc->uc_mcontext.gregs[REG_ERR] = 0;
+  memcpy (&uc->uc_mcontext.gregs[REG_EIP], &sc->sc_eip,
+	  (NGREG - REG_EIP) * sizeof (int));
+
+  /* XXX FPU state.  */
+  memset (&uc->uc_mcontext.fpregs, 0, sizeof (fpregset_t));
+}
+
 struct sigcontext *
 _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
 			int signo, struct hurd_signal_detail *detail,
@@ -43,15 +96,38 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
   struct
     {
       int signo;
-      long int sigcode;
-      struct sigcontext *scp;	/* Points to ctx, below.  */
+      union
+	{
+	  /* Extra arguments for traditional signal handlers */
+	  struct
+	    {
+	      long int sigcode;
+	      struct sigcontext *scp;       /* Points to ctx, below.  */
+	    } legacy;
+
+	  /* Extra arguments for SA_SIGINFO handlers */
+	  struct
+	    {
+	      siginfo_t *siginfop;          /* Points to siginfo, below.  */
+	      ucontext_t *uctxp;            /* Points to uctx, below.  */
+	    } posix;
+	};
       void *sigreturn_addr;
       void *sigreturn_returns_here;
       struct sigcontext *return_scp; /* Same; arg to sigreturn.  */
+
+      /* NB: sigreturn assumes link is next to ctx.  */
       struct sigcontext ctx;
       struct hurd_userlink link;
+      ucontext_t ucontext;
+      siginfo_t siginfo;
     } *stackframe;
 
+  /* sigaction for preemptors */
+  static const struct sigaction legacy_sigaction = {
+    .sa_flags = SA_RESTART
+  };
+
   if (ss->context)
     {
       /* We have a previous sigcontext that sigreturn was about
@@ -94,9 +170,13 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
      the SP on sigreturn.  */
     state->basic.uesp = state->basic.ecx;
 
-  /* XXX what if handler != action->handler (for instance, if a signal
-   * preemptor took over) ? */
   action = & _hurd_sigstate_actions (ss) [signo];
+  if ( (action->sa_flags & SA_SIGINFO)
+        && handler != (__sighandler_t) action->sa_sigaction
+   || !(action->sa_flags & SA_SIGINFO)
+        && handler != action->sa_handler)
+    /* A signal preemptor took over, use legacy semantic.  */
+    action = &legacy_sigaction;
 
   if ((action->sa_flags & SA_ONSTACK)
       && !(ss->sigaltstack.ss_flags & (SS_DISABLE|SS_ONSTACK)))
@@ -140,15 +220,9 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
 	  = &stackframe->link.thread.next;
       ss->active_resources = &stackframe->link;
 
-      /* Set up the arguments for the signal handler.  */
-      stackframe->signo = signo;
-      stackframe->sigcode = detail->code;
-      stackframe->scp = stackframe->return_scp = scp = &stackframe->ctx;
-      stackframe->sigreturn_addr = &__sigreturn;
-      stackframe->sigreturn_returns_here = firewall; /* Crash on return.  */
-
       /* Set up the sigcontext from the current state of the thread.  */
 
+      scp = &stackframe->ctx;
       scp->sc_onstack = ss->sigaltstack.ss_flags & SS_ONSTACK ? 1 : 0;
 
       /* struct sigcontext is laid out so that starting at sc_gs mimics a
@@ -162,6 +236,35 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
 			      &state->fpu, &scp->sc_i386_float_state,
 			      sizeof (state->fpu));
 
+      /* Set up the arguments for the signal handler.  */
+      stackframe->signo = signo;
+      if (action->sa_flags & SA_SIGINFO)
+	{
+	  stackframe->posix.siginfop = &stackframe->siginfo;
+	  stackframe->posix.uctxp = &stackframe->ucontext;
+	  fill_siginfo (&stackframe->siginfo, signo, detail, state);
+	  fill_ucontext (&stackframe->ucontext, scp);
+	}
+      else
+	{
+	  if (detail->exc)
+	    {
+	      int nsigno;
+	      _hurd_exception2signal_legacy (detail, &nsigno);
+	      assert (nsigno == signo);
+	    }
+	  else
+	    detail->code = 0;
+
+	  stackframe->legacy.sigcode = detail->code;
+	  stackframe->legacy.scp = &stackframe->ctx;
+	}
+
+      /* Set up the bottom of the stack.  */
+      stackframe->sigreturn_addr = &__sigreturn;
+      stackframe->sigreturn_returns_here = firewall; /* Crash on return.  */
+      stackframe->return_scp = &stackframe->ctx;
+
       _hurdsig_end_catch_fault ();
 
       if (! ok)