OS-3882 lxbrand execing processes not stopping for PTRACE_O_TRACEEXEC

TritonDataCenter · Mar 17, 2015 · 0905c01 · 0905c01
1 parent 2feca3b
commit 0905c01
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Showing 2 changed files with 35 additions and 3 deletions.
diff --git a/usr/src/uts/common/brand/lx/os/lx_misc.c b/usr/src/uts/common/brand/lx/os/lx_misc.c
@@ -81,6 +81,7 @@ lx_exec()
 	struct lx_lwp_data *lwpd = lwptolxlwp(lwp);
 	proc_t *p = ttoproc(curthread);
 	lx_proc_data_t *pd = ptolxproc(p);
+	struct regs *rp = lwptoregs(lwp);
 	int err;
 
 	/*
@@ -145,6 +146,15 @@ lx_exec()
 	kpreempt_disable();
 	lx_restore(lwp);
 	kpreempt_enable();
+
+	/*
+	 * The exec syscall doesn't return (so we don't call lx_syscall_return)
+	 * but for our ptrace emulation we need to do this so that a tracer
+	 * does not get out of sync. We know that by the time this lx_exec
+	 * function is called that the exec has succeeded.
+	 */
+	rp->r_r0 = 0;
+	lx_ptrace_stop(LX_PR_SYSEXIT);
 }
 
 void

diff --git a/usr/src/uts/common/brand/lx/os/lx_ptrace.c b/usr/src/uts/common/brand/lx/os/lx_ptrace.c
@@ -817,10 +817,17 @@ lx_ptrace_getregs(lx_lwp_data_t *remote, void *uregsp)
 		 */
 		return (lx_regs_to_userregs(remote, uregsp));
 	} else if (remote->br_stack_mode == LX_STACK_MODE_PREINIT &&
-	    remote->br_ptrace_whatstop == LX_PR_SIGNALLED) {
+	    (remote->br_ptrace_whatstop == LX_PR_SIGNALLED ||
+	    remote->br_ptrace_whatstop == LX_PR_SYSEXIT)) {
 		/*
-		 * The LWP was stopped by tracing on exec. br_ptrace_stopucp
-		 * is NULL. Return the LWP register state.
+		 * The LWP was stopped by tracing on exec.
+		 */
+		return (lx_regs_to_userregs(remote, uregsp));
+	} else if (remote->br_stack_mode == LX_STACK_MODE_NATIVE &&
+	    remote->br_ptrace_whystop == PR_BRAND &&
+	    remote->br_ptrace_whatstop == LX_PR_EVENT) {
+		/*
+		 * Called while we're ptrace event stopped by lx_exec.
 		 */
 		return (lx_regs_to_userregs(remote, uregsp));
 	} else if (remote->br_ptrace_stopucp != NULL) {
@@ -1398,15 +1405,30 @@ lx_ptrace_traceme(void)
 static boolean_t
 lx_ptrace_stop_common(proc_t *p, lx_lwp_data_t *lwpd, ushort_t what)
 {
+	boolean_t reset_nostop = B_FALSE;
+
 	VERIFY(MUTEX_HELD(&p->p_lock));
 
 	/*
 	 * Mark this LWP as stopping and call stop() to enter "ptrace-stop".
 	 */
 	VERIFY0(lwpd->br_ptrace_flags & LX_PTRACE_STOPPING);
 	lwpd->br_ptrace_flags |= LX_PTRACE_STOPPING;
+
+	if (lwpd->br_lwp->lwp_nostop == 1 &&
+	    lwpd->br_ptrace_event == LX_PTRACE_EVENT_EXEC) {
+		/* We need to clear this to get the signal delivered. */
+		lwpd->br_lwp->lwp_nostop = 0;
+		reset_nostop = B_TRUE;
+	}
+
 	stop(PR_BRAND, what);
 
+	if (reset_nostop) {
+		VERIFY(lwpd->br_lwp->lwp_nostop == 0);
+		lwpd->br_lwp->lwp_nostop = 1;
+	}
+
 	/*
 	 * We are back from "ptrace-stop" with our process lock held.
 	 */