am 7f38a3c9: Merge "Implement _Exit(3)."

* commit '7f38a3c9bef9c6efc30a6b60873bbdeea04a18f0':
  Implement _Exit(3).

libc/SYSCALLS.TXT

@@ -308,7 +308,7 @@ int __epoll_pwait:epoll_pwait(int, struct epoll_event*, int, int, const sigset_t
 
 int eventfd:eventfd2(unsigned int, int)  all
 
-void _exit:exit_group(int)  all
+void _exit|_Exit:exit_group(int)  all
 void __exit:exit(int)  all
 
 int futex(void*, int, int, void*, void*, int)  all

libc/arch-arm/syscalls/_exit.S

@@ -12,3 +12,6 @@ ENTRY(_exit)
     neg     r0, r0
     b       __set_errno
 END(_exit)
+
+    .globl _Exit
+    .equ _Exit, _exit

libc/arch-arm64/syscalls/_exit.S

@@ -19,3 +19,6 @@ ENTRY(_exit)
 
     ret
 END(_exit)
+
+    .globl _Exit
+    .equ _Exit, _exit

libc/arch-mips/syscalls/_exit.S

@@ -17,3 +17,6 @@ ENTRY(_exit)
     nop
     .set reorder
 END(_exit)
+
+    .globl _Exit
+    .equ _Exit, _exit

libc/arch-mips64/syscalls/_exit.S

@@ -23,3 +23,6 @@ ENTRY(_exit)
     move ra, t0
     .set pop
 END(_exit)
+
+    .globl _Exit
+    .equ _Exit, _exit

libc/arch-x86/syscalls/_exit.S

@@ -20,3 +20,6 @@ ENTRY(_exit)
     popl    %ebx
     ret
 END(_exit)
+
+    .globl _Exit
+    .equ _Exit, _exit

libc/arch-x86_64/syscalls/_exit.S

@@ -14,3 +14,6 @@ ENTRY(_exit)
 1:
     ret
 END(_exit)
+
+    .globl _Exit
+    .equ _Exit, _exit

libc/include/stdlib.h

@@ -41,8 +41,9 @@ __BEGIN_DECLS
 #define EXIT_FAILURE 1
 #define EXIT_SUCCESS 0
 
-extern __noreturn void exit(int);
 extern __noreturn void abort(void);
+extern __noreturn void exit(int);
+extern __noreturn void _Exit(int);
 extern int atexit(void (*)(void));
 
 extern char *getenv(const char *);

tests/stdlib_test.cpp

@@ -202,3 +202,17 @@ TEST(stdlib, strtof) {
 TEST(stdlib, strtold) {
   ASSERT_DOUBLE_EQ(1.23, strtold("1.23", NULL));
 }
+
+TEST(unistd, _Exit) {
+  int pid = fork();
+  ASSERT_NE(-1, pid) << strerror(errno);
+
+  if (pid == 0) {
+    _Exit(99);
+  }
+
+  int status;
+  ASSERT_EQ(pid, waitpid(pid, &status, 0));
+  ASSERT_TRUE(WIFEXITED(status));
+  ASSERT_EQ(99, WEXITSTATUS(status));
+}

tests/unistd_test.cpp

@@ -116,3 +116,17 @@ TEST(unistd, read_EBADF) {
 TEST(unistd, alarm) {
   ASSERT_EQ(0U, alarm(0));
 }
+
+TEST(unistd, _exit) {
+  int pid = fork();
+  ASSERT_NE(-1, pid) << strerror(errno);
+
+  if (pid == 0) {
+    _exit(99);
+  }
+
+  int status;
+  ASSERT_EQ(pid, waitpid(pid, &status, 0));
+  ASSERT_TRUE(WIFEXITED(status));
+  ASSERT_EQ(99, WEXITSTATUS(status));
+}