Support PTRACE_EVENT_VFORK_DONE for vforks via clone(CLONE_VFORK)

Resolves #3560

CMakeLists.txt

@@ -1638,6 +1638,7 @@ set(TESTS_WITHOUT_PROGRAM
  tty
  unmap_vdso
  unwind_on_signal
+ vfork_done_clone
  vfork_exec
  vfork_break_parent
  vsyscall_singlestep

src/record_syscall.cc

@@ -6393,15 +6393,15 @@ static void rec_process_syscall_arch(RecordTask* t,
  // syscall completes --- and that our TaskSyscallState infrastructure can't
  // handle.
  switch (syscallno) {
- case Arch::vfork: {
- if (t->emulated_ptrace_options & PTRACE_O_TRACEVFORKDONE) {
+ case Arch::vfork:
+ case Arch::fork:
+ case Arch::clone:
+ if ((syscallno == Arch::vfork ||
+ (syscallno == Arch::clone && (t->regs().arg1() & CLONE_VFORK))) &&
+ (t->emulated_ptrace_options & PTRACE_O_TRACEVFORKDONE)) {
  t->emulate_ptrace_stop(
  WaitStatus::for_ptrace_event(PTRACE_EVENT_VFORK_DONE));
  }
- RR_FALLTHROUGH;
- }
- case Arch::fork:
- case Arch::clone: {
  if (Arch::is_x86ish()) {
  // On a 3.19.0-39-generic #44-Ubuntu kernel we have observed clone()
  // clearing the parity flag internally.
@@ -6410,7 +6410,6 @@ static void rec_process_syscall_arch(RecordTask* t,
  t->set_regs(r);
  }
  break;
- }
 
  case Arch::execve:
  case Arch::execveat:

src/test/vfork_done.c

@@ -5,42 +5,56 @@
 #include <signal.h>
 
 static int EXECUTION_FENCE_PIPES[2];
+static char force_clone;
+static char stack[65536];
 
 static void seize(const pid_t pid) {
  const int opts =
  PTRACE_O_TRACEVFORK | PTRACE_O_TRACEVFORKDONE | PTRACE_O_TRACESYSGOOD;
  test_assert(0 == ptrace(PTRACE_SEIZE, pid, 0, opts));
 }
 
-static int tracees(void) {
- switch (vfork()) {
- case -1:
- exit(EXIT_FAILURE);
- break;
- // vfork-child
- case 0: {
- long res = 0;
- for(int i = 1; i < 1000000; i++) {
- for(int j = 1; j < 100; j++) {
- res = (res / 3) + 14*i;
- if(res /= res > 2) {
- res = 3;
- }
- }
+static int vfork_child(__attribute__((unused)) void* p) {
+ long res = 0;
+ for (int i = 1; i < 1000000; i++) {
+ for (int j = 1; j < 100; j++) {
+ res = (res / 3) + 14*i;
+ if (res /= res > 2) {
+ res = 3;
  }
- exit(99);
- break;
  }
- // vfork-parent (fork-child)
- default:
- exit(66);
- break;
+ }
+ exit(99);
+ return 0;
+}
+
+static int tracees(void) {
+ pid_t child;
+ if (force_clone) {
+ child = clone(vfork_child, stack + sizeof(stack),
+ CLONE_VFORK | CLONE_VM | SIGCHLD, NULL);
+ } else {
+ child = vfork();
+ if (!child) {
+ vfork_child(NULL);
+ return 0;
+ }
+ }
+ if (child < 0) {
+ exit(EXIT_FAILURE);
+ } else {
+ exit(66);
  }
 }
 
-int main(void) {
+int main(int argc, char** argv) {
  char notify;
  assert(0 == pipe(EXECUTION_FENCE_PIPES));
+
+ if (argc > 1 && !strcmp(argv[1], "clone")) {
+ force_clone = 1;
+ }
+
  pid_t fork_child = fork();
 
  switch (fork_child) {

src/test/vfork_done_clone.run

@@ -0,0 +1,6 @@
+source `dirname $0`/util.sh
+
+save_exe vfork_done$bitness
+just_record vfork_done$bitness-$nonce clone
+replay
+check EXIT-SUCCESS