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Merge "Generalize the clone function slightly."

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am: 0155995e8d

* commit '0155995e8d4471d0e530c8bbfac88c4a8a68fbb1':
  Generalize the clone function slightly.

Change-Id: I40b5ab2913811a7140a1104340f30aaedc8358fc
This commit is contained in:
Elliott Hughes 2016-05-09 20:32:36 +00:00 committed by android-build-merger
commit 6c8de255ec
3 changed files with 20 additions and 10 deletions
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13
libc/bionic/clone.cpp
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@ -47,7 +47,7 @@ int clone(int (*fn)(void*), void* child_stack, int flags, void* arg, ...) {
void* new_tls = NULL;
int* child_tid = NULL;
if (!child_stack) {
if (fn != nullptr && child_stack == nullptr) {
errno = EINVAL;
return -1;
}
@ -76,7 +76,16 @@ int clone(int (*fn)(void*), void* child_stack, int flags, void* arg, ...) {
pid_t parent_pid = self->invalidate_cached_pid();
// Actually do the clone.
int clone_result = __bionic_clone(flags, child_stack, parent_tid, new_tls, child_tid, fn, arg);
int clone_result;
if (fn != nullptr) {
clone_result = __bionic_clone(flags, child_stack, parent_tid, new_tls, child_tid, fn, arg);
} else {
#if defined(__x86_64__) // sys_clone's last two arguments are flipped on x86-64.
clone_result = syscall(__NR_clone, flags, child_stack, parent_tid, child_tid, new_tls);
#else
clone_result = syscall(__NR_clone, flags, child_stack, parent_tid, new_tls, child_tid);
#endif
}
// We're the parent, so put our known pid back in place.
// We leave the child without a cached pid, but:

14
libc/bionic/fork.cpp
View file

@ -31,8 +31,6 @@
#include "pthread_internal.h"
#define FORK_FLAGS (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD)
int fork() {
__bionic_atfork_run_prepare();
@ -41,11 +39,13 @@ int fork() {
// Remember the parent pid and invalidate the cached value while we fork.
pid_t parent_pid = self->invalidate_cached_pid();
#if defined(__x86_64__) // sys_clone's last two arguments are flipped on x86-64.
int result = syscall(__NR_clone, FORK_FLAGS, NULL, NULL, &(self->tid), NULL);
#else
int result = syscall(__NR_clone, FORK_FLAGS, NULL, NULL, NULL, &(self->tid));
#endif
int result = clone(nullptr,
nullptr,
(CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD),
nullptr,
nullptr,
nullptr,
&(self->tid));
if (result == 0) {
self->set_cached_pid(gettid());
__bionic_atfork_run_child();

3
tests/sched_test.cpp
View file

@ -55,7 +55,8 @@ TEST(sched, clone_errno) {
// Check that our hand-written clone assembler sets errno correctly on failure.
uintptr_t fake_child_stack[16];
errno = 0;
ASSERT_EQ(-1, clone(NULL, &fake_child_stack[16], CLONE_THREAD, NULL));
// If CLONE_THREAD is set, CLONE_SIGHAND must be set too.
ASSERT_EQ(-1, clone(child_fn, &fake_child_stack[16], CLONE_THREAD, NULL));
ASSERT_EQ(EINVAL, errno);
}