!88 fix: 进程退出静态问题

Merge pull request !88 from zhushengle/exit

porting/liteos_a/user/src/exit/exit.c

+#include <stdlib.h>
+#include <stdint.h>
+#include <signal.h>
+#include <atomic.h>
+#include "libc.h"
+
+static void dummy()
+{
+}
+
+/* atexit.c and __stdio_exit.c override these. the latter is linked
+ * as a consequence of linking either __toread.c or __towrite.c. */
+weak_alias(dummy, __funcs_on_exit);
+weak_alias(dummy, __stdio_exit);
+weak_alias(dummy, _fini);
+
+extern weak hidden void (*const __fini_array_start)(void), (*const __fini_array_end)(void);
+
+static void libc_exit_fini(void)
+{
+	uintptr_t a = (uintptr_t)&__fini_array_end;
+	for (; a>(uintptr_t)&__fini_array_start; a-=sizeof(void(*)()))
+		(*(void (**)())(a-sizeof(void(*)())))();
+	_fini();
+}
+
+weak_alias(libc_exit_fini, __libc_exit_fini);
+
+_Noreturn void exit(int code)
+{
+	sigset_t set;
+	if (a_cas(&libc.exit, 0, 1) != 0) {
+		return;
+	}
+	__block_app_sigs(&set);
+	__funcs_on_exit();
+	__libc_exit_fini();
+	__stdio_exit();
+	_Exit(code);
+}

porting/liteos_a/user/src/internal/libc.h

@@ -27,6 +27,7 @@ struct __libc {
 	size_t tls_size, tls_align, tls_cnt;
 	size_t page_size;
 	struct __locale_struct global_locale;
+	int exit;
 };
 
 #ifndef PAGE_SIZE

porting/liteos_a/user/src/process/fork.c

@@ -30,6 +30,7 @@ pid_t fork(void)
 		self->next = self->prev = self;
 		__thread_list_lock = 0;
 		libc.threads_minus_1 = 0;
+		libc.exit = 0;
 		signal(SIGSYS, arm_do_signal);
 	}
 	__restore_sigs(&set);

porting/liteos_a/user_debug/src/exit/exit.c

@@ -2,6 +2,8 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <debug.h>
+#include <signal.h>
+#include <atomic.h>
 #include "libc.h"
 
 extern bool g_enable_check;
@@ -32,6 +34,11 @@ weak_alias(libc_exit_fini, __libc_exit_fini);
 
 _Noreturn void exit(int code)
 {
+	sigset_t set;
+	if (a_cas(&libc.exit, 0, 1) != 0) {
+		return;
+	}
+	__block_app_sigs(&set);
 	if (g_enable_check) {
 		check_leak();
 		check_heap_integrity();