am 598f4b3a
: Merge "Fix getpid caching across a clone."
* commit '598f4b3ac1be3c6ef3af613ac4b0694841e165fe': Fix getpid caching across a clone.
This commit is contained in:
commit
1411afd6d1
@ -31,6 +31,8 @@
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#include <stdlib.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdarg.h>
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#include "pthread_internal.h"
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extern "C" pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg);
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extern "C" pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg);
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extern "C" __noreturn void __exit(int status);
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extern "C" __noreturn void __exit(int status);
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@ -64,5 +66,18 @@ int clone(int (*fn)(void*), void* child_stack, int flags, void* arg, ...) {
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child_stack_addr &= ~0xf;
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child_stack_addr &= ~0xf;
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child_stack = reinterpret_cast<void*>(child_stack_addr);
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child_stack = reinterpret_cast<void*>(child_stack_addr);
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return __bionic_clone(flags, child_stack, parent_tid, new_tls, child_tid, fn, arg);
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// Remember the parent pid and invalidate the cached value while we clone.
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pthread_internal_t* self = __get_thread();
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pid_t parent_pid = self->invalidate_cached_pid();
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// Actually do the clone.
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int clone_result = __bionic_clone(flags, child_stack, parent_tid, new_tls, child_tid, fn, arg);
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// We're the parent, so put our known pid back in place.
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// We leave the child without a cached pid, but:
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// 1. pthread_create gives its children their own pthread_internal_t with the correct pid.
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// 2. fork makes a clone system call directly.
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// If any other cases become important, we could use a double trampoline like __pthread_start.
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self->set_cached_pid(parent_pid);
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return clone_result;
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}
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}
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@ -381,6 +381,14 @@ TEST(unistd, fsync) {
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TestFsyncFunction(fsync);
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TestFsyncFunction(fsync);
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}
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}
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static void AssertGetPidCorrect() {
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// The loop is just to make manual testing/debugging with strace easier.
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pid_t getpid_syscall_result = syscall(__NR_getpid);
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for (size_t i = 0; i < 128; ++i) {
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ASSERT_EQ(getpid_syscall_result, getpid());
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}
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}
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TEST(unistd, getpid_caching_and_fork) {
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TEST(unistd, getpid_caching_and_fork) {
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pid_t parent_pid = getpid();
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pid_t parent_pid = getpid();
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ASSERT_EQ(syscall(__NR_getpid), parent_pid);
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ASSERT_EQ(syscall(__NR_getpid), parent_pid);
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@ -389,7 +397,7 @@ TEST(unistd, getpid_caching_and_fork) {
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ASSERT_NE(fork_result, -1);
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ASSERT_NE(fork_result, -1);
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if (fork_result == 0) {
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if (fork_result == 0) {
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// We're the child.
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// We're the child.
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ASSERT_EQ(syscall(__NR_getpid), getpid());
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AssertGetPidCorrect();
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ASSERT_EQ(parent_pid, getppid());
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ASSERT_EQ(parent_pid, getppid());
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_exit(123);
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_exit(123);
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} else {
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} else {
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@ -403,12 +411,29 @@ TEST(unistd, getpid_caching_and_fork) {
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}
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}
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}
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}
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static void GetPidCachingHelperHelper() {
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static int GetPidCachingCloneStartRoutine(void*) {
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ASSERT_EQ(syscall(__NR_getpid), getpid());
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AssertGetPidCorrect();
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return 123;
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}
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}
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static void* GetPidCachingHelper(void*) {
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TEST(unistd, getpid_caching_and_clone) {
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GetPidCachingHelperHelper(); // Can't assert in a non-void function.
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pid_t parent_pid = getpid();
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ASSERT_EQ(syscall(__NR_getpid), parent_pid);
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void* child_stack[1024];
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int clone_result = clone(GetPidCachingCloneStartRoutine, &child_stack[1024], CLONE_NEWNS | SIGCHLD, NULL);
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ASSERT_NE(clone_result, -1);
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ASSERT_EQ(parent_pid, getpid());
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int status;
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ASSERT_EQ(clone_result, waitpid(clone_result, &status, 0));
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ASSERT_TRUE(WIFEXITED(status));
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ASSERT_EQ(123, WEXITSTATUS(status));
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}
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static void* GetPidCachingPthreadStartRoutine(void*) {
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AssertGetPidCorrect();
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return NULL;
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return NULL;
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}
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}
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@ -416,7 +441,7 @@ TEST(unistd, getpid_caching_and_pthread_create) {
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pid_t parent_pid = getpid();
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pid_t parent_pid = getpid();
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pthread_t t;
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pthread_t t;
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ASSERT_EQ(0, pthread_create(&t, NULL, GetPidCachingHelper, NULL));
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ASSERT_EQ(0, pthread_create(&t, NULL, GetPidCachingPthreadStartRoutine, NULL));
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ASSERT_EQ(parent_pid, getpid());
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ASSERT_EQ(parent_pid, getpid());
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