Use <startup.h> in __libc_init_secure

Since __libc_init_secure is called before ARCH_SETUP_TLS, it must use
"int $0x80" for system calls in i386 static PIE.  Add startup_getuid,
startup_geteuid, startup_getgid and startup_getegid to <startup.h>.
Update __libc_init_secure to use them.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

elf/enbl-secure.c

@@ -19,7 +19,7 @@
 /* This file is used in the static libc.  For the shared library,
    dl-sysdep.c defines and initializes __libc_enable_secure.  */
 
-#include <unistd.h>
+#include <startup.h>
 #include <libc-internal.h>
 
 /* If nonzero __libc_enable_secure is already set.  */
@@ -31,6 +31,6 @@ void
 __libc_init_secure (void)
 {
   if (__libc_enable_secure_decided == 0)
-    __libc_enable_secure = (__geteuid () != __getuid ()
-			    || __getegid () != __getgid ());
+    __libc_enable_secure = (startup_geteuid () != startup_getuid ()
+			    || startup_getegid () != startup_getgid ());
 }

sysdeps/generic/startup.h

@@ -19,5 +19,31 @@
 /* Targets should override this file if the default definitions below
    will not work correctly very early before TLS is initialized.  */
 
+#include <unistd.h>
+
 /* Use macro instead of inline function to avoid including <stdio.h>.  */
 #define _startup_fatal(message) __libc_fatal ((message))
+
+static inline uid_t
+startup_getuid (void)
+{
+  return __getuid ();
+}
+
+static inline uid_t
+startup_geteuid (void)
+{
+  return __geteuid ();
+}
+
+static inline gid_t
+startup_getgid (void)
+{
+  return __getgid ();
+}
+
+static inline gid_t
+startup_getegid (void)
+{
+  return __getegid ();
+}

sysdeps/unix/sysv/linux/i386/startup.h

@@ -17,11 +17,12 @@
    <https://www.gnu.org/licenses/>.  */
 
 #if BUILD_PIE_DEFAULT
-# include <abort-instr.h>
-
 /* Can't use "call *%gs:SYSINFO_OFFSET" during statup in static PIE.  */
 # define I386_USE_SYSENTER 0
 
+# include <sysdep.h>
+# include <abort-instr.h>
+
 __attribute__ ((__noreturn__))
 static inline void
 _startup_fatal (const char *message __attribute__ ((unused)))
@@ -31,6 +32,30 @@ _startup_fatal (const char *message __attribute__ ((unused)))
   ABORT_INSTRUCTION;
   __builtin_unreachable ();
 }
+
+static inline uid_t
+startup_getuid (void)
+{
+  return (uid_t) INTERNAL_SYSCALL_CALL (getuid32);
+}
+
+static inline uid_t
+startup_geteuid (void)
+{
+  return (uid_t) INTERNAL_SYSCALL_CALL (geteuid32);
+}
+
+static inline gid_t
+startup_getgid (void)
+{
+  return (gid_t) INTERNAL_SYSCALL_CALL (getgid32);
+}
+
+static inline gid_t
+startup_getegid (void)
+{
+  return (gid_t) INTERNAL_SYSCALL_CALL (getegid32);
+}
 #else
 # include_next <startup.h>
 #endif