path: root/0027-Make-ELF-constructors-and-destructors-work.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Fri, 23 Aug 2019 16:23:21 -0400
Subject: [PATCH] Make ELF constructors and destructors work.

This makes setup and teardown functions defined with
__attribute__((__constructor__) and __attribute__((__destructor__)) work
in normal circumstances in EFI binaries.

A couple of notes:
- it implements both the old-style .ctors/.dtors methods and the newer
  style .init_array/.fini_array ELF constructor and destructor arrays,
  processed in the order:
    .init_array[]
    .ctors[]
    efi_main()
    .dtors[]
    .fini_array[]
- Destructors will only be called if efi_main() exits using "return";
  any call to Exit() will still longjmp() past them.
- InitializeLib() has already been called before constructors run, so
  they don't need to call it (and neither does anything else.)  For
  compatibility, it has been altered so calling it more than once is
  safe.
- No attempt is made to handle any constructor or destructor with a
  prototype other than "void func(void);", but note that InitializeLib
  has been called, so LibImageHandle, ST, BS, and RT are set.
- The init_array/ctor/dtor/fini_array lists aren't the using the GNU
  "CONSTRUCTOR" output section command, so they don't start with a size.
- The lists are individually sorted during the link stage via
  SORT_BY_NAME() in the linker script.
- The default (empty) init_array/ctor/dtor/fini_array lists are padded
  out to 8-byte alignment with ".p2align 3, 0", and each list always has
  at least one ".long 0" at the end of it (even if it's completely
  empty).  As a result, they can have NULLs that need to be skipped.
  The sections they're in are mergeable, so the NULLs don't have to be
  exclusively at the end.
- The ia64 and mips64el arches have not been tested.

Signed-off-by: Peter Jones <pjones@redhat.com>
---
 apps/Makefile                |  5 ++-
 apps/ctors_fns.c             | 26 +++++++++++++
 apps/ctors_test.c            | 20 ++++++++++
 gnuefi/crt0-efi-aa64.S       |  2 +-
 gnuefi/crt0-efi-arm.S        |  2 +-
 gnuefi/crt0-efi-ia32.S       |  8 ++--
 gnuefi/crt0-efi-ia64.S       |  2 +-
 gnuefi/crt0-efi-mips64el.S   |  4 +-
 gnuefi/crt0-efi-x64.S        |  2 +-
 gnuefi/elf_aa64_efi.lds      | 21 +++++++++++
 gnuefi/elf_arm_efi.lds       | 20 ++++++++++
 gnuefi/elf_ia32_efi.lds      | 21 +++++++++++
 gnuefi/elf_ia32_fbsd_efi.lds | 21 +++++++++++
 gnuefi/elf_ia64_efi.lds      | 21 +++++++++++
 gnuefi/elf_mips64el_efi.lds  | 20 ++++++++++
 gnuefi/elf_x64_efi.lds       | 22 +++++++++++
 gnuefi/elf_x64_fbsd_efi.lds  | 21 +++++++++++
 lib/Makefile                 |  6 +--
 lib/ctors.S                  | 43 ++++++++++++++++++++++
 lib/entry.c                  | 67 ++++++++++++++++++++++++++++++++++
 lib/init.c                   | 87 +++++++++++++++++++++-----------------------
 21 files changed, 381 insertions(+), 60 deletions(-)
 create mode 100644 apps/ctors_fns.c
 create mode 100644 apps/ctors_test.c
 create mode 100644 lib/ctors.S
 create mode 100644 lib/entry.c

diff --git a/apps/Makefile b/apps/Makefile
index a95620cba2d..28088370da7 100644
--- a/apps/Makefile
+++ b/apps/Makefile
@@ -62,7 +62,8 @@ TARGET_APPS = t.efi t2.efi t3.efi t4.efi t5.efi t6.efi \
 	      printenv.efi t7.efi t8.efi tcc.efi modelist.efi \
 	      route80h.efi drv0_use.efi AllocPages.efi exit.efi \
 	      FreePages.efi setjmp.efi debughook.efi debughook.efi.debug \
-	      bltgrid.efi lfbgrid.efi setdbg.efi unsetdbg.efi
+	      bltgrid.efi lfbgrid.efi setdbg.efi unsetdbg.efi \
+	      ctors_test.efi
 TARGET_BSDRIVERS = drv0.efi
 TARGET_RTDRIVERS =
 
@@ -87,6 +88,8 @@ TARGETS = $(TARGET_APPS) $(TARGET_BSDRIVERS) $(TARGET_RTDRIVERS)
 
 all:	$(TARGETS)
 
+ctors_test.so : ctors_fns.o ctors_test.o
+
 clean:
 	rm -f $(TARGETS) *~ *.o *.so
 
diff --git a/apps/ctors_fns.c b/apps/ctors_fns.c
new file mode 100644
index 00000000000..624190462ea
--- /dev/null
+++ b/apps/ctors_fns.c
@@ -0,0 +1,26 @@
+/*
+ * ctors.c
+ * Copyright 2019 Peter Jones <pjones@redhat.com>
+ *
+ */
+
+#include <efi.h>
+#include <efilib.h>
+
+int constructed_value = 0;
+
+static void __attribute__((__constructor__)) ctor(void)
+{
+	Print(L"%a:%d:%a() constructed_value:%d\n", __FILE__, __LINE__, __func__, constructed_value);
+	constructed_value = 1;
+	Print(L"%a:%d:%a() constructed_value:%d\n", __FILE__, __LINE__, __func__, constructed_value);
+}
+
+static void __attribute__((__destructor__)) dtor(void)
+{
+	Print(L"%a:%d:%a() constructed_value:%d\n", __FILE__, __LINE__, __func__, constructed_value);
+	constructed_value = 0;
+	Print(L"%a:%d:%a() constructed_value:%d\n", __FILE__, __LINE__, __func__, constructed_value);
+}
+
+// vim:fenc=utf-8:tw=75:noet
diff --git a/apps/ctors_test.c b/apps/ctors_test.c
new file mode 100644
index 00000000000..7e48da8ef35
--- /dev/null
+++ b/apps/ctors_test.c
@@ -0,0 +1,20 @@
+/*
+ * ctors_test.c
+ * Copyright 2019 Peter Jones <pjones@redhat.com>
+ *
+ */
+
+#include <efi.h>
+#include <efilib.h>
+
+extern int constructed_value;
+
+EFI_STATUS
+efi_main (EFI_HANDLE image EFI_UNUSED, EFI_SYSTEM_TABLE *systab EFI_UNUSED)
+{
+	Print(L"%a:%d:%a() constructed_value:%d\n", __FILE__, __LINE__, __func__, constructed_value);
+
+	return EFI_SUCCESS;
+}
+
+// vim:fenc=utf-8:tw=75:noet
diff --git a/gnuefi/crt0-efi-aa64.S b/gnuefi/crt0-efi-aa64.S
index d6e610b8c79..a9302588b71 100644
--- a/gnuefi/crt0-efi-aa64.S
+++ b/gnuefi/crt0-efi-aa64.S
@@ -124,7 +124,7 @@ _start:
 	cbnz		x0, 0f
 
 	ldp		x0, x1, [sp, #16]
-	bl		efi_main
+	bl		_entry
 
 0:	ldp		x29, x30, [sp], #32
 	ret
diff --git a/gnuefi/crt0-efi-arm.S b/gnuefi/crt0-efi-arm.S
index c5bb6d482da..04e75e9481a 100644
--- a/gnuefi/crt0-efi-arm.S
+++ b/gnuefi/crt0-efi-arm.S
@@ -136,7 +136,7 @@ _start:
 	bne		0f
 
 	ldmfd		sp, {r0-r1}
-	bl		efi_main
+	bl		_entry
 
 0:	add		sp, sp, #12
 	ldr		pc, [sp], #4
diff --git a/gnuefi/crt0-efi-ia32.S b/gnuefi/crt0-efi-ia32.S
index f9d5191ecb5..8e8e372f551 100644
--- a/gnuefi/crt0-efi-ia32.S
+++ b/gnuefi/crt0-efi-ia32.S
@@ -56,13 +56,13 @@ _start:
 	call _relocate
 	popl %ebx
 	popl %ebx
- 	testl %eax,%eax
- 	jne .exit
+	testl %eax,%eax
+	jne .exit
   
-  	call efi_main			# call app with "image" and "systab" argument
+	call _entry			# call app with "image" and "systab" argument
 
 .exit:	leave
-  	ret
+	ret
  
  	// hand-craft a dummy .reloc section so EFI knows it's a relocatable executable:
  
diff --git a/gnuefi/crt0-efi-ia64.S b/gnuefi/crt0-efi-ia64.S
index 40c3c837a1c..dacb4c4c658 100644
--- a/gnuefi/crt0-efi-ia64.S
+++ b/gnuefi/crt0-efi-ia64.S
@@ -56,7 +56,7 @@ _start:
 
 	mov out0=in0			// image handle
 	mov out1=in1			// systab
-	br.call.sptk.few rp=efi_main
+	br.call.sptk.few rp=_entry
 .Lret2:
 .exit:
 	mov ar.pfs=loc0
diff --git a/gnuefi/crt0-efi-mips64el.S b/gnuefi/crt0-efi-mips64el.S
index 6a62aca98b4..5ad2503ca79 100644
--- a/gnuefi/crt0-efi-mips64el.S
+++ b/gnuefi/crt0-efi-mips64el.S
@@ -172,8 +172,8 @@ _pc:
 
 	// a0: ImageHandle
 	ld		$a0, 16($sp)
-	// call efi_main
-	dla		$t9, efi_main
+	// call _start
+	dla		$t9, _entry
 	jalr		$t9
 	// a1: SystemTable
 	ld		$a1, 24($sp)
diff --git a/gnuefi/crt0-efi-x64.S b/gnuefi/crt0-efi-x64.S
index 6533af7461f..3fe361b7ffd 100644
--- a/gnuefi/crt0-efi-x64.S
+++ b/gnuefi/crt0-efi-x64.S
@@ -56,7 +56,7 @@ _start:
 	popq %rdi
 	popq %rsi
 
-	call efi_main
+	call _entry
 	addq $8, %rsp
 
 .exit:	
diff --git a/gnuefi/elf_aa64_efi.lds b/gnuefi/elf_aa64_efi.lds
index 836d98255d8..161f5fc5641 100644
--- a/gnuefi/elf_aa64_efi.lds
+++ b/gnuefi/elf_aa64_efi.lds
@@ -26,6 +26,26 @@ SECTIONS
    *(.got.plt)
    *(.got)
 
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    . = ALIGN(16);
@@ -36,6 +56,7 @@ SECTIONS
    *(.bss)
    *(COMMON)
    . = ALIGN(16);
+
    _bss_end = .;
   }
 
diff --git a/gnuefi/elf_arm_efi.lds b/gnuefi/elf_arm_efi.lds
index 665bbdbf065..f93f39bc384 100644
--- a/gnuefi/elf_arm_efi.lds
+++ b/gnuefi/elf_arm_efi.lds
@@ -26,6 +26,26 @@ SECTIONS
    *(.got.plt)
    *(.got)
 
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    . = ALIGN(16);
diff --git a/gnuefi/elf_ia32_efi.lds b/gnuefi/elf_ia32_efi.lds
index f27fe5fc6e6..4b7e3f1df39 100644
--- a/gnuefi/elf_ia32_efi.lds
+++ b/gnuefi/elf_ia32_efi.lds
@@ -40,6 +40,27 @@ SECTIONS
    *(.sdata)
    *(.got.plt)
    *(.got)
+
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    *(.sbss)
diff --git a/gnuefi/elf_ia32_fbsd_efi.lds b/gnuefi/elf_ia32_fbsd_efi.lds
index cd309e24f7f..9e9baec2aca 100644
--- a/gnuefi/elf_ia32_fbsd_efi.lds
+++ b/gnuefi/elf_ia32_fbsd_efi.lds
@@ -40,6 +40,27 @@ SECTIONS
    *(.sdata)
    *(.got.plt)
    *(.got)
+
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    *(.sbss)
diff --git a/gnuefi/elf_ia64_efi.lds b/gnuefi/elf_ia64_efi.lds
index 190792a0c94..2cda0dd97c7 100644
--- a/gnuefi/elf_ia64_efi.lds
+++ b/gnuefi/elf_ia64_efi.lds
@@ -39,6 +39,27 @@ SECTIONS
    *(.data*)
    *(.gnu.linkonce.d*)
    *(.plabel)	/* data whose relocs we want to ignore */
+
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    *(.dynbss)
diff --git a/gnuefi/elf_mips64el_efi.lds b/gnuefi/elf_mips64el_efi.lds
index 4d1a077d8f8..0e68084d103 100644
--- a/gnuefi/elf_mips64el_efi.lds
+++ b/gnuefi/elf_mips64el_efi.lds
@@ -27,6 +27,26 @@ SECTIONS
    HIDDEN (_gp = ALIGN (16) + 0x7ff0);
    *(.got)
 
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    . = ALIGN(16);
diff --git a/gnuefi/elf_x64_efi.lds b/gnuefi/elf_x64_efi.lds
index c7a105898c8..cb2e3dc00aa 100644
--- a/gnuefi/elf_x64_efi.lds
+++ b/gnuefi/elf_x64_efi.lds
@@ -30,6 +30,7 @@ SECTIONS
   {
    *(.reloc)
   }
+
   . = ALIGN(4096);
   .data :
   {
@@ -39,6 +40,27 @@ SECTIONS
    *(.got)
    *(.data*)
    *(.sdata)
+
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    *(.sbss)
diff --git a/gnuefi/elf_x64_fbsd_efi.lds b/gnuefi/elf_x64_fbsd_efi.lds
index 705719bf68b..192aa065d8c 100644
--- a/gnuefi/elf_x64_fbsd_efi.lds
+++ b/gnuefi/elf_x64_fbsd_efi.lds
@@ -36,6 +36,27 @@ SECTIONS
    *(.got)
    *(.data*)
    *(.sdata)
+
+   /*
+    * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+    * command, so they don't start with a size.  Because of p2align and the
+    * end/END definitions, and the fact that they're mergeable, they can also
+    * have NULLs which aren't guaranteed to be at the end.
+    */
+   . = ALIGN(16);
+   _init_array = .;
+   *(SORT_BY_NAME(.init_array))
+   _init_array_end = .;
+   __CTOR_LIST__ = .;
+   *(SORT_BY_NAME(.ctors))
+   __CTOR_END__ = .;
+   __DTOR_LIST__ = .;
+   *(SORT_BY_NAME(.dtors))
+   __DTOR_END__ = .;
+   _fini_array = .;
+   *(SORT_BY_NAME(.fini_array))
+   _fini_array_end = .;
+
    /* the EFI loader doesn't seem to like a .bss section, so we stick
       it all into .data: */
    *(.sbss)
diff --git a/lib/Makefile b/lib/Makefile
index 8bf94000e33..e7eafc01f1e 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -43,8 +43,8 @@ include $(SRCDIR)/../Make.defaults
 TOPDIR = $(SRCDIR)/..
 
 CDIR = $(TOPDIR)/..
-FILES = boxdraw smbios console crc data debug dpath  \
-        error event exit guid hand hw init lock   \
+FILES = boxdraw smbios console crc data debug dpath \
+        entry error event exit guid hand hw init lock \
         misc print sread str cmdline \
 	runtime/rtlock runtime/efirtlib runtime/rtstr runtime/vm runtime/rtdata  \
 	$(ARCH)/initplat $(ARCH)/math $(ARCH)/setjmp
@@ -62,7 +62,7 @@ FILES += $(ARCH)/uldiv $(ARCH)/ldivmod $(ARCH)/div $(ARCH)/llsl $(ARCH)/llsr \
 	 $(ARCH)/mullu
 endif
 
-OBJS  = $(FILES:%=%.o)
+OBJS  = $(FILES:%=%.o) ctors.o
 
 SUBDIRS = ia32 x64 ia64 aa64 arm mips64el runtime
 
diff --git a/lib/ctors.S b/lib/ctors.S
new file mode 100644
index 00000000000..522d31b90d2
--- /dev/null
+++ b/lib/ctors.S
@@ -0,0 +1,43 @@
+/*
+ * Try to define the minimal empty init/ctor/dtor/fini_arrays so building with
+ * older or out-of-tree linker scripts will still work.
+ */
+/*
+ * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+ * command, so they don't start with a size.  Because of p2align and the
+ * end/END definitions, and the fact that they're mergeable, they can also
+ * have NULLs which aren't guaranteed to be at the end.
+ */
+	.section .init_array, "aM", @init_array
+	.p2align 3, 0
+	.globl _init_array
+_init_array:
+	.p2align 3, 0
+	.globl _init_array_end
+_init_array_end:
+	.long 0
+	.section .ctors, "aM", @init_array
+	.p2align 3, 0
+	.globl __CTOR_LIST__
+__CTOR_LIST__:
+	.p2align 3, 0
+	.globl __CTOR_END__
+__CTOR_END__:
+	.long 0
+	.section .dtors, "aM", @fini_array
+	.p2align 3, 0
+	.globl __DTOR_LIST__
+__DTOR_LIST__:
+	.p2align 3, 0
+	.globl __DTOR_END__
+__DTOR_END__:
+	.long 0
+	.section .fini_array, "aM", @fini_array
+	.p2align 3, 0
+	.globl _fini_array
+_fini_array:
+	.p2align 3, 0
+	.globl _fini_array_end
+_fini_array_end:
+	.long 0
+
diff --git a/lib/entry.c b/lib/entry.c
new file mode 100644
index 00000000000..d8526084602
--- /dev/null
+++ b/lib/entry.c
@@ -0,0 +1,67 @@
+/*
+ * ctors.c
+ * Copyright 2019 Peter Jones <pjones@redhat.com>
+ *
+ */
+
+#include <efi.h>
+#include <efilib.h>
+
+/*
+ * Note that these aren't the using the GNU "CONSTRUCTOR" output section
+ * command, so they don't start with a size.  Because of p2align and the
+ * end/END definitions, and the fact that they're mergeable, they can also
+ * have NULLs which aren't guaranteed to be at the end.
+ */
+extern UINTN _init_array, _init_array_end;
+extern UINTN __CTOR_LIST__, __CTOR_END__;
+extern UINTN _fini_array, _fini_array_end;
+extern UINTN __DTOR_LIST__, __DTOR_END__;
+
+typedef void (*funcp)(void);
+
+static void ctors(void)
+{
+	for (funcp *location = (void *)&_init_array; location < (funcp *)&_init_array_end; location++) {
+		funcp func = *location;
+		if (location != NULL)
+			func();
+	}
+
+	for (funcp *location = (void *)&__CTOR_LIST__; location < (funcp *)&__CTOR_END__; location++) {
+		funcp func = *location;
+		if (location != NULL)
+			func();
+	}
+}
+
+static void dtors(void)
+{
+	for (funcp *location = (void *)&__DTOR_LIST__; location < (funcp *)&__DTOR_END__; location++) {
+		funcp func = *location;
+		if (location != NULL)
+			func();
+	}
+
+	for (funcp *location = (void *)&_fini_array; location < (funcp *)&_fini_array_end; location++) {
+		funcp func = *location;
+		if (location != NULL)
+			func();
+	}
+}
+
+extern EFI_STATUS efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *systab);
+
+EFI_STATUS _entry(EFI_HANDLE image, EFI_SYSTEM_TABLE *systab)
+{
+	EFI_STATUS status;
+	InitializeLib(image, systab);
+
+	ctors();
+	status = efi_main(image, systab);
+	dtors();
+
+	return status;
+}
+
+// vim:fenc=utf-8:tw=75:noet
diff --git a/lib/init.c b/lib/init.c
index 4f238c0a2cc..726e493919a 100644
--- a/lib/init.c
+++ b/lib/init.c
@@ -46,57 +46,52 @@ Returns:
     EFI_STATUS              Status;
     CHAR8                   *LangCode;
 
-    if (!LibInitialized) {
-        LibInitialized = TRUE;
-        LibFwInstance = FALSE;
-        LibImageHandle = ImageHandle;
-
-
-        //
-        // Set up global pointer to the system table, boot services table,
-        // and runtime services table
-        //
-
-        ST = SystemTable;
-        BS = SystemTable->BootServices;
-        RT = SystemTable->RuntimeServices;
-//        ASSERT (CheckCrc(0, &ST->Hdr));
-//        ASSERT (CheckCrc(0, &BS->Hdr));
-//        ASSERT (CheckCrc(0, &RT->Hdr));
-
-
-        //
-        // Initialize pool allocation type
-        //
-
-        if (ImageHandle) {
-            Status = uefi_call_wrapper(
-                BS->HandleProtocol,
-                3,
-                ImageHandle, 
-                &LoadedImageProtocol,
-                (VOID*)&LoadedImage
-            );
-
-            if (!EFI_ERROR(Status)) {
-                PoolAllocationType = LoadedImage->ImageDataType;
-            }
-            EFIDebugVariable ();
-        }
-
-        //
-        // Initialize Guid table
-        //
-
-        InitializeGuid();
-
-        InitializeLibPlatform(ImageHandle,SystemTable);
+    if (LibInitialized)
+	return;
+
+    LibInitialized = TRUE;
+    LibFwInstance = FALSE;
+    LibImageHandle = ImageHandle;
+
+    //
+    // Set up global pointer to the system table, boot services table,
+    // and runtime services table
+    //
+
+    ST = SystemTable;
+    BS = SystemTable->BootServices;
+    RT = SystemTable->RuntimeServices;
+    // ASSERT (CheckCrc(0, &ST->Hdr));
+    // ASSERT (CheckCrc(0, &BS->Hdr));
+    // ASSERT (CheckCrc(0, &RT->Hdr));
+
+    //
+    // Initialize pool allocation type
+    //
+
+    if (ImageHandle) {
+	Status = uefi_call_wrapper(
+	    BS->HandleProtocol,
+	    3,
+	    ImageHandle,
+	    &LoadedImageProtocol,
+	    (VOID*)&LoadedImage
+	);
+
+	if (!EFI_ERROR(Status)) {
+	    PoolAllocationType = LoadedImage->ImageDataType;
+	}
+	EFIDebugVariable ();
     }
 
     //
-    // 
+    // Initialize Guid table
     //
 
+    InitializeGuid();
+
+    InitializeLibPlatform(ImageHandle,SystemTable);
+
     if (ImageHandle && UnicodeInterface == &LibStubUnicodeInterface) {
         LangCode = LibGetVariable (VarLanguage, &EfiGlobalVariable);
         InitializeUnicodeSupport (LangCode);