agent/src/os/bsd/MacosxDebuggerLocal.m
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rev 4136 : 8008102: SA on OS X does not stop the attached process
Reviewed-by:
@@ -36,10 +36,12 @@
#import <stdlib.h>
#import <strings.h>
#import <dlfcn.h>
#import <limits.h>
#import <errno.h>
+#import <sys/types.h>
+#import <sys/ptrace.h>
jboolean debug = JNI_FALSE;
static jfieldID symbolicatorID = 0; // set in _init0
static jfieldID taskID = 0; // set in _init0
@@ -428,10 +430,77 @@
printf("translateTID0: 0x%x -> 0x%x\n", foreign_tid, usable_tid);
return (jint) usable_tid;
}
+
+static bool ptrace_continue(pid_t pid, int signal) {
+ // pass the signal to the process so we don't swallow it
+ int res;
+ if ((res = ptrace(PT_CONTINUE, pid, (caddr_t)1, signal)) < 0) {
+ fprintf(stderr, "attach: ptrace(PT_CONTINUE, %d) failed with %d\n", pid, res);
+ return false;
+ }
+ return true;
+}
+
+// waits until the ATTACH has stopped the process
+// by signal SIGSTOP
+static bool ptrace_waitpid(pid_t pid) {
+ int ret;
+ int status;
+ while (true) {
+ // Wait for debuggee to stop.
+ ret = waitpid(pid, &status, 0);
+ if (ret >= 0) {
+ if (WIFSTOPPED(status)) {
+ // Any signal will stop the thread, make sure it is SIGSTOP. Otherwise SIGSTOP
+ // will still be pending and delivered when the process is DETACHED and the process
+ // will go to sleep.
+ if (WSTOPSIG(status) == SIGSTOP) {
+ // Debuggee stopped by SIGSTOP.
+ return true;
+ }
+ if (!ptrace_continue(pid, WSTOPSIG(status))) {
+ fprintf(stderr, "attach: Failed to correctly attach to VM. VM might HANG! [PTRACE_CONT failed, stopped by %d]\n", WSTOPSIG(status));
+ return false;
+ }
+ } else {
+ fprintf(stderr, "attach: waitpid(): Child process exited/terminated (status = 0x%x)\n", status);
+ return false;
+ }
+ } else {
+ switch (errno) {
+ case EINTR:
+ continue;
+ break;
+ case ECHILD:
+ fprintf(stderr, "attach: waitpid() failed. Child process pid (%d) does not exist \n", pid);
+ break;
+ case EINVAL:
+ fprintf(stderr, "attach: waitpid() failed. Invalid options argument.\n");
+ break;
+ default:
+ fprintf(stderr, "attach: waitpid() failed. Unexpected error %d\n",errno);
+ break;
+ }
+ return false;
+ }
+ }
+}
+
+// attach to a process/thread specified by "pid"
+static bool ptrace_attach(pid_t pid) {
+ int res;
+ if ((res = ptrace(PT_ATTACH, pid, 0, 0)) < 0) {
+ fprintf(stderr, "ptrace(PT_ATTACH, %d) failed with %d\n", pid, res);
+ return false;
+ } else {
+ return ptrace_waitpid(pid);
+ }
+}
+
/*
* Class: sun_jvm_hotspot_debugger_bsd_BsdDebuggerLocal
* Method: attach0
* Signature: (I)V
*/
@@ -444,19 +513,27 @@
debug = JNI_TRUE;
else
debug = JNI_FALSE;
if (debug) printf("attach0 called for jpid=%d\n", (int)jpid);
+ // get the task from the pid
kern_return_t result;
task_t gTask = 0;
result = task_for_pid(mach_task_self(), jpid, &gTask);
if (result != KERN_SUCCESS) {
fprintf(stderr, "attach: task_for_pid(%d) failed (%d)\n", (int)jpid, result);
THROW_NEW_DEBUGGER_EXCEPTION("Can't attach to the process");
}
putTask(env, this_obj, gTask);
+ // use ptrace to stop the process
+ // on os x, ptrace only needs to be called on the process, not the individual threads
+ if (ptrace_attach(jpid) != true) {
+ mach_port_deallocate(mach_task_self(), gTask);
+ THROW_NEW_DEBUGGER_EXCEPTION("Can't attach to the process");
+ }
+
id symbolicator = nil;
id jrsSymbolicator = objc_lookUpClass("JRSSymbolicator");
if (jrsSymbolicator != nil) {
id (*dynamicCall)(id, SEL, pid_t) = (id (*)(id, SEL, pid_t))&objc_msgSend;
symbolicator = dynamicCall(jrsSymbolicator, @selector(symbolicatorForPid:), (pid_t)jpid);
@@ -484,10 +561,25 @@
{
JNF_COCOA_ENTER(env);
if (debug) printf("detach0 called\n");
task_t gTask = getTask(env, this_obj);
+
+ // detach from the ptraced process causing it to resume execution
+ int pid;
+ kern_return_t k_res;
+ k_res = pid_for_task(gTask, &pid);
+ if (k_res != KERN_SUCCESS) {
+ fprintf(stderr, "detach: pid_for_task(%d) failed (%d)\n", pid, k_res);
+ }
+ else {
+ int res = ptrace(PT_DETACH, pid, 0, 0);
+ if (res < 0) {
+ fprintf(stderr, "detach: ptrace(PT_DETACH, %d) failed (%d)\n", pid, res);
+ }
+ }
+
mach_port_deallocate(mach_task_self(), gTask);
id symbolicator = getSymbolicator(env, this_obj);
if (symbolicator != nil) {
CFRelease(symbolicator);
}