Implement thread creation.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4693 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 25b9e5a..d020228 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -74,6 +74,11 @@
#if defined(USE_NPTL)
#include <linux/futex.h>
+#define CLONE_NPTL_FLAGS2 (CLONE_SETTLS | \
+ CLONE_PARENT_SETTID | CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)
+#else
+/* XXX: Hardcode the above values. */
+#define CLONE_NPTL_FLAGS2 0
#endif
//#define DEBUG
@@ -2706,6 +2711,48 @@
#endif /* defined(TARGET_I386) */
+#if defined(USE_NPTL)
+
+#define NEW_STACK_SIZE PTHREAD_STACK_MIN
+
+static pthread_mutex_t clone_lock = PTHREAD_MUTEX_INITIALIZER;
+typedef struct {
+ CPUState *env;
+ pthread_mutex_t mutex;
+ pthread_cond_t cond;
+ pthread_t thread;
+ uint32_t tid;
+ abi_ulong child_tidptr;
+ abi_ulong parent_tidptr;
+ sigset_t sigmask;
+} new_thread_info;
+
+static void *clone_func(void *arg)
+{
+ new_thread_info *info = arg;
+ CPUState *env;
+
+ env = info->env;
+ thread_env = env;
+ info->tid = gettid();
+ if (info->child_tidptr)
+ put_user_u32(info->tid, info->child_tidptr);
+ if (info->parent_tidptr)
+ put_user_u32(info->tid, info->parent_tidptr);
+ /* Enable signals. */
+ sigprocmask(SIG_SETMASK, &info->sigmask, NULL);
+ /* Signal to the parent that we're ready. */
+ pthread_mutex_lock(&info->mutex);
+ pthread_cond_broadcast(&info->cond);
+ pthread_mutex_unlock(&info->mutex);
+ /* Wait until the parent has finshed initializing the tls state. */
+ pthread_mutex_lock(&clone_lock);
+ pthread_mutex_unlock(&clone_lock);
+ cpu_loop(env);
+ /* never exits */
+ return NULL;
+}
+#else
/* this stack is the equivalent of the kernel stack associated with a
thread/process */
#define NEW_STACK_SIZE 8192
@@ -2717,24 +2764,27 @@
/* never exits */
return 0;
}
+#endif
/* do_fork() Must return host values and target errnos (unlike most
do_*() functions). */
-int do_fork(CPUState *env, unsigned int flags, abi_ulong newsp)
+static int do_fork(CPUState *env, unsigned int flags, abi_ulong newsp,
+ abi_ulong parent_tidptr, target_ulong newtls,
+ abi_ulong child_tidptr)
{
int ret;
TaskState *ts;
uint8_t *new_stack;
CPUState *new_env;
+#if defined(USE_NPTL)
+ unsigned int nptl_flags;
+ sigset_t sigmask;
+#endif
if (flags & CLONE_VM) {
#if defined(USE_NPTL)
- /* qemu is not threadsafe. Bail out immediately if application
- tries to create a thread. */
- if (!(flags & CLONE_VFORK)) {
- gemu_log ("clone(CLONE_VM) not supported\n");
- return -EINVAL;
- }
+ new_thread_info info;
+ pthread_attr_t attr;
#endif
ts = malloc(sizeof(TaskState) + NEW_STACK_SIZE);
init_task_state(ts);
@@ -2744,19 +2794,94 @@
/* Init regs that differ from the parent. */
cpu_clone_regs(new_env, newsp);
new_env->opaque = ts;
+#if defined(USE_NPTL)
+ nptl_flags = flags;
+ flags &= ~CLONE_NPTL_FLAGS2;
+
+ /* TODO: Implement CLONE_CHILD_CLEARTID. */
+ if (nptl_flags & CLONE_SETTLS)
+ cpu_set_tls (new_env, newtls);
+
+ /* Grab a mutex so that thread setup appears atomic. */
+ pthread_mutex_lock(&clone_lock);
+
+ memset(&info, 0, sizeof(info));
+ pthread_mutex_init(&info.mutex, NULL);
+ pthread_mutex_lock(&info.mutex);
+ pthread_cond_init(&info.cond, NULL);
+ info.env = new_env;
+ if (nptl_flags & CLONE_CHILD_SETTID)
+ info.child_tidptr = child_tidptr;
+ if (nptl_flags & CLONE_PARENT_SETTID)
+ info.parent_tidptr = parent_tidptr;
+
+ ret = pthread_attr_init(&attr);
+ ret = pthread_attr_setstack(&attr, new_stack, NEW_STACK_SIZE);
+ /* It is not safe to deliver signals until the child has finished
+ initializing, so temporarily block all signals. */
+ sigfillset(&sigmask);
+ sigprocmask(SIG_BLOCK, &sigmask, &info.sigmask);
+
+ ret = pthread_create(&info.thread, &attr, clone_func, &info);
+
+ sigprocmask(SIG_SETMASK, &info.sigmask, NULL);
+ pthread_attr_destroy(&attr);
+ if (ret == 0) {
+ /* Wait for the child to initialize. */
+ pthread_cond_wait(&info.cond, &info.mutex);
+ ret = info.tid;
+ if (flags & CLONE_PARENT_SETTID)
+ put_user_u32(ret, parent_tidptr);
+ } else {
+ ret = -1;
+ }
+ pthread_mutex_unlock(&info.mutex);
+ pthread_cond_destroy(&info.cond);
+ pthread_mutex_destroy(&info.mutex);
+ pthread_mutex_unlock(&clone_lock);
+#else
+ if (flags & CLONE_NPTL_FLAGS2)
+ return -EINVAL;
+ /* This is probably going to die very quickly, but do it anyway. */
#ifdef __ia64__
ret = __clone2(clone_func, new_stack + NEW_STACK_SIZE, flags, new_env);
#else
ret = clone(clone_func, new_stack + NEW_STACK_SIZE, flags, new_env);
#endif
+#endif
} else {
/* if no CLONE_VM, we consider it is a fork */
- if ((flags & ~CSIGNAL) != 0)
+ if ((flags & ~(CSIGNAL | CLONE_NPTL_FLAGS2)) != 0)
return -EINVAL;
+ fork_start();
ret = fork();
+#if defined(USE_NPTL)
+ /* There is a race condition here. The parent process could
+ theoretically read the TID in the child process before the child
+ tid is set. This would require using either ptrace
+ (not implemented) or having *_tidptr to point at a shared memory
+ mapping. We can't repeat the spinlock hack used above because
+ the child process gets its own copy of the lock. */
+ if (ret == 0) {
+ cpu_clone_regs(env, newsp);
+ fork_end(1);
+ /* Child Process. */
+ if (flags & CLONE_CHILD_SETTID)
+ put_user_u32(gettid(), child_tidptr);
+ if (flags & CLONE_PARENT_SETTID)
+ put_user_u32(gettid(), parent_tidptr);
+ ts = (TaskState *)env->opaque;
+ if (flags & CLONE_SETTLS)
+ cpu_set_tls (env, newtls);
+ /* TODO: Implement CLONE_CHILD_CLEARTID. */
+ } else {
+ fork_end(0);
+ }
+#else
if (ret == 0) {
cpu_clone_regs(env, newsp);
}
+#endif
}
return ret;
}
@@ -3153,7 +3278,7 @@
ret = do_brk(arg1);
break;
case TARGET_NR_fork:
- ret = get_errno(do_fork(cpu_env, SIGCHLD, 0));
+ ret = get_errno(do_fork(cpu_env, SIGCHLD, 0, 0, 0, 0));
break;
#ifdef TARGET_NR_waitpid
case TARGET_NR_waitpid:
@@ -4531,7 +4656,7 @@
ret = get_errno(fsync(arg1));
break;
case TARGET_NR_clone:
- ret = get_errno(do_fork(cpu_env, arg1, arg2));
+ ret = get_errno(do_fork(cpu_env, arg1, arg2, arg3, arg4, arg5));
break;
#ifdef __NR_exit_group
/* new thread calls */
@@ -4967,7 +5092,8 @@
#endif
#ifdef TARGET_NR_vfork
case TARGET_NR_vfork:
- ret = get_errno(do_fork(cpu_env, CLONE_VFORK | CLONE_VM | SIGCHLD, 0));
+ ret = get_errno(do_fork(cpu_env, CLONE_VFORK | CLONE_VM | SIGCHLD,
+ 0, 0, 0, 0));
break;
#endif
#ifdef TARGET_NR_ugetrlimit
