[glibc/release/2.34/master] Linux: Implement a useful version of _startup_fatal

[glibc/release/2.34/master] Linux: Implement a useful version of _startup_fatal

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e7ca2a475cf2e7ffc987b8d08e1a40337840b500

commit e7ca2a475cf2e7ffc987b8d08e1a40337840b500
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon May 9 18:15:16 2022 +0200

    Linux: Implement a useful version of _startup_fatal
    
    On i386 and ia64, the TCB is not available at this point.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
    (cherry picked from commit a2a6bce7d7e52c1c34369a7da62c501cc350bc31)

Diff:
---
 sysdeps/unix/sysv/linux/i386/startup.h | 23 ++++----------------
 sysdeps/unix/sysv/linux/ia64/startup.h | 22 +++++++++++++++++++
 sysdeps/unix/sysv/linux/startup.h      | 39 ++++++++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+), 19 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/i386/startup.h b/sysdeps/unix/sysv/linux/i386/startup.h
index 192c765361..213805d7d2 100644
--- a/sysdeps/unix/sysv/linux/i386/startup.h
+++ b/sysdeps/unix/sysv/linux/i386/startup.h
@@ -1,5 +1,5 @@
 /* Linux/i386 definitions of functions used by static libc main startup.
-   Copyright (C) 2017-2021 Free Software Foundation, Inc.
+   Copyright (C) 2022 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -16,22 +16,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#if BUILD_PIE_DEFAULT
-/* Can't use "call *%gs:SYSINFO_OFFSET" during statup in static PIE.  */
-# define I386_USE_SYSENTER 0
+/* Can't use "call *%gs:SYSINFO_OFFSET" during startup.  */
+#define I386_USE_SYSENTER 0
 
-# include <sysdep.h>
-# include <abort-instr.h>
-
-__attribute__ ((__noreturn__))
-static inline void
-_startup_fatal (const char *message __attribute__ ((unused)))
-{
-  /* This is only called very early during startup in static PIE.
-     FIXME: How can it be improved?  */
-  ABORT_INSTRUCTION;
-  __builtin_unreachable ();
-}
-#else
-# include_next <startup.h>
-#endif
+#include_next <startup.h>
diff --git a/sysdeps/unix/sysv/linux/ia64/startup.h b/sysdeps/unix/sysv/linux/ia64/startup.h
new file mode 100644
index 0000000000..77f29f15a2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/ia64/startup.h
@@ -0,0 +1,22 @@
+/* Linux/ia64 definitions of functions used by static libc main startup.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* This code is used before the TCB is set up.  */
+#define IA64_USE_NEW_STUB 0
+
+#include_next <startup.h>
diff --git a/sysdeps/unix/sysv/linux/startup.h b/sysdeps/unix/sysv/linux/startup.h
new file mode 100644
index 0000000000..39859b404a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/startup.h
@@ -0,0 +1,39 @@
+/* Linux definitions of functions used by static libc main startup.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifdef SHARED
+# include_next <startup.h>
+#else
+# include <sysdep.h>
+
+/* Avoid a run-time invocation of strlen.  */
+#define _startup_fatal(message)                                         \
+  do                                                                    \
+    {                                                                   \
+      size_t __message_length = __builtin_strlen (message);             \
+      if (! __builtin_constant_p (__message_length))                    \
+        {                                                               \
+          extern void _startup_fatal_not_constant (void);               \
+          _startup_fatal_not_constant ();                               \
+        }                                                               \
+      INTERNAL_SYSCALL_CALL (write, STDERR_FILENO, (message),           \
+                             __message_length);                         \
+      INTERNAL_SYSCALL_CALL (exit_group, 127);                          \
+    }                                                                   \
+  while (0)
+#endif  /* !SHARED */