Implement the assembly glue
It does not work yet though.
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43
src/arch/amd64/loader.S
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43
src/arch/amd64/loader.S
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@ -0,0 +1,43 @@
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/* $Id$ */
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/* Copyright (c) 2021 Pierre Pronchery <khorben@defora.org> */
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/* This file is part of DeforaOS System Loader */
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/* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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.section .text
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.global loader_enter
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.type loader_enter,@function
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.type _loader_enter_do,@function
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loader_enter:
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/* reset the stack */
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xor %rbp, %rbp
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call _loader_enter_do
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call _exit
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_loader_enter_do:
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jmp *%r8
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40
src/arch/i386/loader.S
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40
src/arch/i386/loader.S
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@ -0,0 +1,40 @@
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/* $Id$ */
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/* Copyright (c) 2021 Pierre Pronchery <khorben@defora.org> */
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/* This file is part of DeforaOS System Loader */
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/* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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.section .text
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.global loader_enter
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.type loader_enter,@function
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loader_enter:
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/* reset the stack */
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xor %ebp, %ebp
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mov 0x10(%esp), %eax /* entrypoint */
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jmp *%eax
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34
src/loader.c
34
src/loader.c
@ -53,10 +53,15 @@ static int _prot(int flags);
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/* public */
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/* variables */
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extern char ** environ;
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/* functions */
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/* loader */
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static int _loader_do(int fd, char const * filename, int argc, char * argv[]);
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static int _do_phdr(int fd, char const * filename, Elf_Ehdr * ehdr);
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static int _do_phdr(int fd, char const * filename, Elf_Ehdr * ehdr,
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void ** entrypoint);
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static size_t _do_phdr_align_bits(unsigned long align);
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static int _do_shdr(int fd, char const * filename, Elf_Ehdr * ehdr);
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static int _do_shdr_rela(int fd, char const * filename, Elf_Shdr * shdr,
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@ -78,6 +83,7 @@ static int _loader_do(int fd, char const * filename, int argc, char * argv[])
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{
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int ret;
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Elf_Ehdr ehdr;
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void * entrypoint = NULL;
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if(read(fd, &ehdr, sizeof(ehdr)) != sizeof(ehdr))
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return _error(2, "%s: %s", filename, strerror(errno));
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@ -90,16 +96,22 @@ static int _loader_do(int fd, char const * filename, int argc, char * argv[])
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if(ehdr.e_ehsize != sizeof(ehdr))
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return _error(2, "%s: %s", filename,
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"Invalid or unsupported ELF file");
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if((ret = _do_phdr(fd, filename, &ehdr)) != 0
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if((ret = _do_phdr(fd, filename, &ehdr, &entrypoint)) != 0
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|| (ret = _do_shdr(fd, filename, &ehdr)) != 0)
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return ret;
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if(entrypoint == NULL)
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return _error(2, "%s: %s", filename, "Entrypoint not set");
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#ifdef DEBUG
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fprintf(stderr, "DEBUG: e_entry=%#lx\n", (unsigned long)ehdr.e_entry);
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fprintf(stderr, "DEBUG: loader_enter(%d, %p, %p, %p, %p)\n",
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argc, argv, environ, NULL, entrypoint);
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#endif
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ret = loader_enter(argc, argv, environ, NULL, entrypoint);
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_exit(ret);
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return 0;
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}
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static int _do_phdr(int fd, char const * filename, Elf_Ehdr * ehdr)
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static int _do_phdr(int fd, char const * filename, Elf_Ehdr * ehdr,
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void ** entrypoint)
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{
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Elf_Phdr phdr;
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size_t i;
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@ -203,8 +215,18 @@ static int _do_phdr(int fd, char const * filename, Elf_Ehdr * ehdr)
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return _error(2, "%s: %s", filename,
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strerror(errno));
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}
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/* FIXME keep this value */
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phdr.p_vaddr = (intptr_t)addr;
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if(prot & PROT_EXEC)
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{
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*entrypoint = (char *)(ehdr->e_entry - phdr.p_vaddr
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+ (intptr_t)addr);
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#ifdef DEBUG
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fprintf(stderr, "DEBUG: e_entry=%#lx p_vaddr=%#lx"
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" addr=%p => %p\n",
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(unsigned long)ehdr->e_entry,
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(unsigned long)phdr.p_vaddr,
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addr, *entrypoint);
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#endif
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}
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}
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return 0;
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}
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@ -36,5 +36,7 @@
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/* public */
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/* functions */
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int loader(char const * filename, int argc, char * argv[]);
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int loader_enter(int argc, char * argv[], char ** envp, void * auxv,
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void * entrypoint);
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#endif /* !LOADER_LOADER_H */
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@ -1,4 +1,6 @@
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targets=ld.so,ld.so-i386
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as=$(CC)
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asflags=$(CPPFLAGSF) $(CPPFLAGS) $(CFLAGSF) $(CFLAGS) -c
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cppflags_force=
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cflags_force=-g
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cflags=-W -Wall -O2 -D_FORTIFY_SOURCE=2 -fstack-protector
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@ -49,7 +51,7 @@ cflags_force=
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#targets
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[ld.so]
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type=binary
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sources=loader.c,main.c
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sources=arch/amd64/loader.S,loader.c,main.c
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install=$(PREFIX)/libexec
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[ld.so-arm]
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@ -61,7 +63,8 @@ install=$(PREFIX)/libexec
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[ld.so-i386]
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type=binary
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sources=loader32.c,main32.c
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sources=arch/i386/loader.S,loader32.c,main32.c
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asflags=-m32
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cflags=-m32
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ldflags=-m32
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install=$(PREFIX)/libexec
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