[efi] Eliminate use of libbfd

Parse the intermediate ELF file directly instead of using libbfd, in
order to allow for cross-compiled ELF objects.

As a side bonus, this eliminates libbfd as a build requirement.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 294 insertions, 169 deletions

diff --git a/src/util/elf2efi.c b/src/util/elf2efi.c
index dee70ee7..5e1050e3 100644
--- a/src/util/elf2efi.c
+++ b/src/util/elf2efi.c
@@ -17,9 +17,6 @@
  * 02110-1301, USA.
  */
 
-#define _GNU_SOURCE
-#define PACKAGE "elf2efi"
-#define PACKAGE_VERSION "1"
 #define FILE_LICENCE(...) extern void __file_licence ( void )
 #include <stdint.h>
 #include <stddef.h>
@@ -30,15 +27,65 @@
 #include <errno.h>
 #include <assert.h>
 #include <getopt.h>
-#include <bfd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <elf.h>
 #include <ipxe/efi/Uefi.h>
 #include <ipxe/efi/IndustryStandard/PeImage.h>
 #include <libgen.h>
 
 #define eprintf(...) fprintf ( stderr, __VA_ARGS__ )
 
+#ifdef EFI_TARGET32
+
+#define EFI_IMAGE_NT_HEADERS		EFI_IMAGE_NT_HEADERS32
+#define EFI_IMAGE_NT_OPTIONAL_HDR_MAGIC	EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC
+#define EFI_IMAGE_FILE_MACHINE		EFI_IMAGE_FILE_32BIT_MACHINE
+#define ELFCLASS   ELFCLASS32
+#define Elf_Ehdr   Elf32_Ehdr
+#define Elf_Shdr   Elf32_Shdr
+#define Elf_Sym    Elf32_Sym
+#define Elf_Addr   Elf32_Addr
+#define Elf_Rel    Elf32_Rel
+#define Elf_Rela   Elf32_Rela
+#define ELF_R_TYPE ELF32_R_TYPE
+#define ELF_R_SYM  ELF32_R_SYM
+
+#elif defined(EFI_TARGET64)
+
+#define EFI_IMAGE_NT_HEADERS		EFI_IMAGE_NT_HEADERS64
+#define EFI_IMAGE_NT_OPTIONAL_HDR_MAGIC	EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC
+#define EFI_IMAGE_FILE_MACHINE		0
+#define ELFCLASS   ELFCLASS64
+#define Elf_Ehdr   Elf64_Ehdr
+#define Elf_Shdr   Elf64_Shdr
+#define Elf_Sym    Elf64_Sym
+#define Elf_Addr   Elf64_Addr
+#define Elf_Rel    Elf64_Rel
+#define Elf_Rela   Elf64_Rela
+#define ELF_R_TYPE ELF64_R_TYPE
+#define ELF_R_SYM  ELF64_R_SYM
+
+#endif
+
 #define EFI_FILE_ALIGN 0x20
 
+struct elf_machine {
+	unsigned int pe_machine;
+	unsigned int r_none;
+	unsigned int r_abs;
+	unsigned int r_pcrel;
+};
+
+struct elf_file {
+	void *data;
+	size_t len;
+	const Elf_Ehdr *ehdr;
+	struct elf_machine *machine;
+};
+
 struct pe_section {
 	struct pe_section *next;
 	EFI_IMAGE_SECTION_HEADER hdr;
@@ -57,11 +104,7 @@ struct pe_relocs {
 struct pe_header {
 	EFI_IMAGE_DOS_HEADER dos;
 	uint8_t padding[128];
-#if defined(EFI_TARGET_IA32)
-	EFI_IMAGE_NT_HEADERS32 nt;
-#elif defined(EFI_TARGET_X64)
-	EFI_IMAGE_NT_HEADERS64 nt;
-#endif
+	EFI_IMAGE_NT_HEADERS nt;
 };
 
 static struct pe_header efi_pe_header = {
@@ -72,26 +115,15 @@ static struct pe_header efi_pe_header = {
 	.nt = {
 		.Signature = EFI_IMAGE_NT_SIGNATURE,
 		.FileHeader = {
-#if defined(EFI_TARGET_IA32)
-			.Machine = EFI_IMAGE_MACHINE_IA32,
-#elif defined(EFI_TARGET_X64)
-			.Machine = EFI_IMAGE_MACHINE_X64,
-#endif
 			.TimeDateStamp = 0x10d1a884,
 			.SizeOfOptionalHeader =
 				sizeof ( efi_pe_header.nt.OptionalHeader ),
 			.Characteristics = ( EFI_IMAGE_FILE_DLL |
-#if defined(EFI_TARGET_IA32)
-					     EFI_IMAGE_FILE_32BIT_MACHINE |
-#endif
+					     EFI_IMAGE_FILE_MACHINE |
 					     EFI_IMAGE_FILE_EXECUTABLE_IMAGE ),
 		},
 		.OptionalHeader = {
-#if defined(EFI_TARGET_IA32)
-			.Magic = EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC,
-#elif defined(EFI_TARGET_X64)
-			.Magic = EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC,
-#endif
+			.Magic = EFI_IMAGE_NT_OPTIONAL_HDR_MAGIC,
 			.MajorLinkerVersion = 42,
 			.MinorLinkerVersion = 42,
 			.SectionAlignment = EFI_FILE_ALIGN,
@@ -104,6 +136,20 @@ static struct pe_header efi_pe_header = {
 	},
 };
 
+static struct elf_machine machine_i386 = {
+	.pe_machine = EFI_IMAGE_MACHINE_IA32,
+	.r_none = R_386_NONE,
+	.r_abs = R_386_32,
+	.r_pcrel = R_386_PC32,
+};
+
+static struct elf_machine machine_x86_64 = {
+	.pe_machine = EFI_IMAGE_MACHINE_X64,
+	.r_none = R_X86_64_NONE,
+	.r_abs = R_X86_64_64,
+	.r_pcrel = R_X86_64_PC32,
+};
+
 /** Command-line options */
 struct options {
 	unsigned int subsystem;
@@ -235,110 +281,155 @@ static size_t output_pe_reltab ( struct pe_relocs *pe_reltab,
 }
 
 /**
- * Open input BFD file
+ * Read input ELF file
  *
- * @v filename		File name
- * @ret ibfd		BFD file
+ * @v name		File name
+ * @v elf		ELF file
  */
-static bfd * open_input_bfd ( const char *filename ) {
-	bfd *bfd;
-
-	/* Open the file */
-	bfd = bfd_openr ( filename, NULL );
-	if ( ! bfd ) {
-		eprintf ( "Cannot open %s: ", filename );
-		bfd_perror ( NULL );
+static void read_elf_file ( const char *name, struct elf_file *elf ) {
+	static const unsigned char ident[] = {
+		ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3, ELFCLASS, ELFDATA2LSB
+	};
+	struct stat stat;
+	const Elf_Ehdr *ehdr;
+	const Elf_Shdr *shdr;
+	void *data;
+	size_t offset;
+	unsigned int i;
+	int fd;
+
+	/* Open file */
+	fd = open ( name, O_RDONLY );
+	if ( fd < 0 ) {
+		eprintf ( "Could not open %s: %s\n", name, strerror ( errno ) );
 		exit ( 1 );
 	}
 
-	/* The call to bfd_check_format() must be present, otherwise
-	 * we get a segfault from later BFD calls.
-	 */
-	if ( ! bfd_check_format ( bfd, bfd_object ) ) {
-		eprintf ( "%s is not an object file: ", filename );
-		bfd_perror ( NULL );
+	/* Get file size */
+	if ( fstat ( fd, &stat ) < 0 ) {
+		eprintf ( "Could not get size of %s: %s\n",
+			  name, strerror ( errno ) );
 		exit ( 1 );
 	}
+	elf->len = stat.st_size;
 
-	return bfd;
-}
-
-/**
- * Read symbol table
- *
- * @v bfd		BFD file
- */
-static asymbol ** read_symtab ( bfd *bfd ) {
-	long symtab_size;
-	asymbol **symtab;
-	long symcount;
-
-	/* Get symbol table size */
-	symtab_size = bfd_get_symtab_upper_bound ( bfd );
-	if ( symtab_size < 0 ) {
-		bfd_perror ( "Could not get symbol table upper bound" );
+	/* Map file */
+	data = mmap ( NULL, elf->len, PROT_READ, MAP_SHARED, fd, 0 );
+	if ( data == MAP_FAILED ) {
+		eprintf ( "Could not map %s: %s\n", name, strerror ( errno ) );
 		exit ( 1 );
 	}
+	elf->data = data;
 
-	/* Allocate and read symbol table */
-	symtab = xmalloc ( symtab_size );
-	symcount = bfd_canonicalize_symtab ( bfd, symtab );
-	if ( symcount < 0 ) {
-		bfd_perror ( "Cannot read symbol table" );
+	/* Close file */
+	close ( fd );
+
+	/* Check header */
+	ehdr = elf->data;
+	if ( ( elf->len < sizeof ( *ehdr ) ) ||
+	     ( memcmp ( ident, ehdr->e_ident, sizeof ( ident ) ) != 0 ) ) {
+		eprintf ( "Invalid ELF header in %s\n", name );
 		exit ( 1 );
 	}
+	elf->ehdr = ehdr;
+
+	/* Check section headers */
+	for ( i = 0 ; i < ehdr->e_shnum ; i++ ) {
+		offset = ( ehdr->e_shoff + ( i * ehdr->e_shentsize ) );
+		if ( elf->len < ( offset + sizeof ( *shdr ) ) ) {
+			eprintf ( "ELF section header outside file in %s\n",
+				  name );
+			exit ( 1 );
+		}
+		shdr = ( data + offset );
+		if ( ( shdr->sh_type != SHT_NOBITS ) &&
+		     ( ( elf->len < shdr->sh_offset ) ||
+		       ( ( ( elf->len - shdr->sh_offset ) < shdr->sh_size ) ))){
+			eprintf ( "ELF section %d outside file in %s\n",
+				  i, name );
+			exit ( 1 );
+		}
+		if ( shdr->sh_link >= ehdr->e_shnum ) {
+			eprintf ( "ELF section %d link section %d out of "
+				  "range\n", i, shdr->sh_link );
+			exit ( 1 );
+		}
+	}
 
-	return symtab;
+	/* Identify architecture */
+	switch ( ehdr->e_machine ) {
+	case EM_386:
+		elf->machine = &machine_i386;
+		break;
+	case EM_X86_64:
+		elf->machine = &machine_x86_64;
+		break;
+	default:
+		eprintf ( "Unknown ELF architecture %d\n", ehdr->e_machine );
+		exit ( 1 );
+	}
 }
 
 /**
- * Read relocation table
+ * Get ELF string
  *
- * @v bfd		BFD file
- * @v symtab		Symbol table
- * @v section		Section
- * @v symtab		Symbol table
- * @ret reltab		Relocation table
+ * @v elf		ELF file
+ * @v section		String table section number
+ * @v offset		String table offset
+ * @ret string		ELF string
  */
-static arelent ** read_reltab ( bfd *bfd, asymbol **symtab,
-				asection *section ) {
-	long reltab_size;
-	arelent **reltab;
-	long numrels;
-
-	/* Get relocation table size */
-	reltab_size = bfd_get_reloc_upper_bound ( bfd, section );
-	if ( reltab_size < 0 ) {
-		bfd_perror ( "Could not get relocation table upper bound" );
+static const char * elf_string ( struct elf_file *elf, unsigned int section,
+				 size_t offset ) {
+	const Elf_Ehdr *ehdr = elf->ehdr;
+	const Elf_Shdr *shdr;
+	char *string;
+	char *last;
+
+	/* Locate section header */
+	if ( section >= ehdr->e_shnum ) {
+		eprintf ( "Invalid ELF string section %d\n", section );
 		exit ( 1 );
 	}
+	shdr = ( elf->data + ehdr->e_shoff + ( section * ehdr->e_shentsize ) );
 
-	/* Allocate and read relocation table */
-	reltab = xmalloc ( reltab_size );
-	numrels = bfd_canonicalize_reloc ( bfd, section, reltab, symtab );
-	if ( numrels < 0 ) {
-		bfd_perror ( "Cannot read relocation table" );
+	/* Sanity check section */
+	if ( shdr->sh_type != SHT_STRTAB ) {
+		eprintf ( "ELF section %d (type %d) is not a string table\n",
+			  section, shdr->sh_type );
+		exit ( 1 );
+	}
+	last = ( elf->data + shdr->sh_offset + shdr->sh_size - 1 );
+	if ( *last != '\0' ) {
+		eprintf ( "ELF section %d is not NUL-terminated\n", section );
 		exit ( 1 );
 	}
 
-	return reltab;
+	/* Locate string */
+	if ( offset >= shdr->sh_size ) {
+		eprintf ( "Invalid ELF string offset %zd in section %d\n",
+			  offset, section );
+		exit ( 1 );
+	}
+	string = ( elf->data + shdr->sh_offset + offset );
+
+	return string;
 }
 
 /**
  * Process section
  *
- * @v bfd		BFD file
+ * @v elf		ELF file
+ * @v shdr		ELF section header
  * @v pe_header		PE file header
- * @v section		Section
  * @ret new		New PE section
  */
-static struct pe_section * process_section ( bfd *bfd,
-					     struct pe_header *pe_header,
-					     asection *section ) {
+static struct pe_section * process_section ( struct elf_file *elf,
+					     const Elf_Shdr *shdr,
+					     struct pe_header *pe_header ) {
 	struct pe_section *new;
+	const char *name;
 	size_t section_memsz;
 	size_t section_filesz;
-	unsigned long flags = bfd_get_section_flags ( bfd, section );
 	unsigned long code_start;
 	unsigned long code_end;
 	unsigned long data_start;
@@ -349,12 +440,15 @@ static struct pe_section * process_section ( bfd *bfd,
 	unsigned long *applicable_start;
 	unsigned long *applicable_end;
 
+	/* Get section name */
+	name = elf_string ( elf, elf->ehdr->e_shstrndx, shdr->sh_name );
+
 	/* Extract current RVA limits from file header */
 	code_start = pe_header->nt.OptionalHeader.BaseOfCode;
 	code_end = ( code_start + pe_header->nt.OptionalHeader.SizeOfCode );
-#if defined(EFI_TARGET_IA32)
+#if defined(EFI_TARGET32)
 	data_start = pe_header->nt.OptionalHeader.BaseOfData;
-#elif defined(EFI_TARGET_X64)
+#elif defined(EFI_TARGET64)
 	data_start = code_end;
 #endif
 	data_mid = ( data_start +
@@ -363,21 +457,21 @@ static struct pe_section * process_section ( bfd *bfd,
 		     pe_header->nt.OptionalHeader.SizeOfUninitializedData );
 
 	/* Allocate PE section */
-	section_memsz = bfd_section_size ( bfd, section );
-	section_filesz = ( ( flags & SEC_LOAD ) ?
+	section_memsz = shdr->sh_size;
+	section_filesz = ( ( shdr->sh_type == SHT_PROGBITS ) ?
 			   efi_file_align ( section_memsz ) : 0 );
 	new = xmalloc ( sizeof ( *new ) + section_filesz );
 	memset ( new, 0, sizeof ( *new ) + section_filesz );
 
 	/* Fill in section header details */
-	strncpy ( ( char * ) new->hdr.Name, section->name,
-		  sizeof ( new->hdr.Name ) );
+	strncpy ( ( char * ) new->hdr.Name, name, sizeof ( new->hdr.Name ) );
 	new->hdr.Misc.VirtualSize = section_memsz;
-	new->hdr.VirtualAddress = bfd_get_section_vma ( bfd, section );
+	new->hdr.VirtualAddress = shdr->sh_addr;
 	new->hdr.SizeOfRawData = section_filesz;
 
 	/* Fill in section characteristics and update RVA limits */
-	if ( flags & SEC_CODE ) {
+	if ( ( shdr->sh_type == SHT_PROGBITS ) &&
+	     ( shdr->sh_flags & SHF_EXECINSTR ) ) {
 		/* .text-type section */
 		new->hdr.Characteristics =
 			( EFI_IMAGE_SCN_CNT_CODE |
@@ -386,7 +480,8 @@ static struct pe_section * process_section ( bfd *bfd,
 			  EFI_IMAGE_SCN_MEM_READ );
 		applicable_start = &code_start;
 		applicable_end = &code_end;
-	} else if ( flags & SEC_DATA ) {
+	} else if ( ( shdr->sh_type == SHT_PROGBITS ) &&
+		    ( shdr->sh_flags & SHF_WRITE ) ) {
 		/* .data-type section */
 		new->hdr.Characteristics =
 			( EFI_IMAGE_SCN_CNT_INITIALIZED_DATA |
@@ -395,7 +490,7 @@ static struct pe_section * process_section ( bfd *bfd,
 			  EFI_IMAGE_SCN_MEM_WRITE );
 		applicable_start = &data_start;
 		applicable_end = &data_mid;
-	} else if ( flags & SEC_READONLY ) {
+	} else if ( shdr->sh_type == SHT_PROGBITS ) {
 		/* .rodata-type section */
 		new->hdr.Characteristics =
 			( EFI_IMAGE_SCN_CNT_INITIALIZED_DATA |
@@ -403,7 +498,7 @@ static struct pe_section * process_section ( bfd *bfd,
 			  EFI_IMAGE_SCN_MEM_READ );
 		applicable_start = &data_start;
 		applicable_end = &data_mid;
-	} else if ( ! ( flags & SEC_LOAD ) ) {
+	} else if ( shdr->sh_type == SHT_NOBITS ) {
 		/* .bss-type section */
 		new->hdr.Characteristics =
 			( EFI_IMAGE_SCN_CNT_UNINITIALIZED_DATA |
@@ -413,19 +508,15 @@ static struct pe_section * process_section ( bfd *bfd,
 		applicable_start = &data_mid;
 		applicable_end = &data_end;
 	} else {
-		eprintf ( "Unrecognised characteristics %#lx for section %s\n",
-			  flags, section->name );
+		eprintf ( "Unrecognised characteristics for section %s\n",
+			  name );
 		exit ( 1 );
 	}
 
 	/* Copy in section contents */
-	if ( flags & SEC_LOAD ) {
-		if ( ! bfd_get_section_contents ( bfd, section, new->contents,
-						  0, section_memsz ) ) {
-			eprintf ( "Cannot read section %s: ", section->name );
-			bfd_perror ( NULL );
-			exit ( 1 );
-		}
+	if ( shdr->sh_type == SHT_PROGBITS ) {
+		memcpy ( new->contents, ( elf->data + shdr->sh_offset ),
+			 shdr->sh_size );
 	}
 
 	/* Update RVA limits */
@@ -445,7 +536,7 @@ static struct pe_section * process_section ( bfd *bfd,
 	/* Write RVA limits back to file header */
 	pe_header->nt.OptionalHeader.BaseOfCode = code_start;
 	pe_header->nt.OptionalHeader.SizeOfCode = ( code_end - code_start );
-#if defined(EFI_TARGET_IA32)
+#if defined(EFI_TARGET32)
 	pe_header->nt.OptionalHeader.BaseOfData = data_start;
 #endif
 	pe_header->nt.OptionalHeader.SizeOfInitializedData =
@@ -465,47 +556,77 @@ static struct pe_section * process_section ( bfd *bfd,
 /**
  * Process relocation record
  *
- * @v bfd		BFD file
- * @v section		Section
- * @v rel		Relocation entry
+ * @v elf		ELF file
+ * @v shdr		ELF section header
+ * @v syms		Symbol table
+ * @v nsyms		Number of symbol table entries
+ * @v rel		Relocation record
  * @v pe_reltab		PE relocation table to fill in
  */
-static void process_reloc ( bfd *bfd __attribute__ (( unused )),
-			    asection *section, arelent *rel,
-			    struct pe_relocs **pe_reltab ) {
-	reloc_howto_type *howto = rel->howto;
-	asymbol *sym = *(rel->sym_ptr_ptr);
-	unsigned long offset = ( bfd_get_section_vma ( bfd, section ) +
-				 rel->address );
-
-	if ( bfd_is_abs_section ( sym->section ) ) {
+static void process_reloc ( struct elf_file *elf, const Elf_Shdr *shdr,
+			    const Elf_Sym *syms, unsigned int nsyms,
+			    const Elf_Rel *rel, struct pe_relocs **pe_reltab ) {
+	unsigned int type = ELF_R_TYPE ( rel->r_info );
+	unsigned int sym = ELF_R_SYM ( rel->r_info );
+	size_t offset = ( shdr->sh_addr + rel->r_offset );
+
+	/* Look up symbol and process relocation */
+	if ( sym >= nsyms ) {
+		eprintf ( "Symbol out of range\n" );
+		exit ( 1 );
+	}
+	if ( syms[sym].st_shndx == SHN_ABS ) {
 		/* Skip absolute symbols; the symbol value won't
 		 * change when the object is loaded.
 		 */
-	} else if ( ( strcmp ( howto->name, "R_386_NONE" ) == 0 ) ||
-		    ( strcmp ( howto->name, "R_X86_64_NONE" ) == 0 ) ) {
+	} else if ( type == elf->machine->r_none ) {
 		/* Ignore dummy relocations used by REQUIRE_SYMBOL() */
-	} else if ( strcmp ( howto->name, "R_X86_64_64" ) == 0 ) {
-		/* Generate an 8-byte PE relocation */
-		generate_pe_reloc ( pe_reltab, offset, 8 );
-	} else if ( strcmp ( howto->name, "R_386_32" ) == 0 ) {
-		/* Generate a 4-byte PE relocation */
-		generate_pe_reloc ( pe_reltab, offset, 4 );
-	} else if ( strcmp ( howto->name, "R_386_16" ) == 0 ) {
-		/* Generate a 2-byte PE relocation */
-		generate_pe_reloc ( pe_reltab, offset, 2 );
-	} else if ( ( strcmp ( howto->name, "R_386_PC32" ) == 0 ) ||
-		    ( strcmp ( howto->name, "R_X86_64_PC32" ) == 0 ) ) {
+	} else if ( type == elf->machine->r_abs ) {
+		/* Generate an 8-byte or 4-byte PE relocation */
+		generate_pe_reloc ( pe_reltab, offset, sizeof ( Elf_Addr ) );
+	} else if ( type == elf->machine->r_pcrel ) {
 		/* Skip PC-relative relocations; all relative offsets
 		 * remain unaltered when the object is loaded.
 		 */
 	} else {
-		eprintf ( "Unrecognised relocation type %s\n", howto->name );
+		eprintf ( "Unrecognised relocation type %d\n", type );
 		exit ( 1 );
 	}
 }
 
 /**
+ * Process relocation records
+ *
+ * @v elf		ELF file
+ * @v shdr		ELF section header
+ * @v stride		Relocation record size
+ * @v pe_reltab		PE relocation table to fill in
+ */
+static void process_relocs ( struct elf_file *elf, const Elf_Shdr *shdr,
+			     size_t stride, struct pe_relocs **pe_reltab ) {
+	const Elf_Shdr *symtab;
+	const Elf_Sym *syms;
+	const Elf_Rel *rel;
+	unsigned int nsyms;
+	unsigned int nrels;
+	unsigned int i;
+
+	/* Identify symbol table */
+	symtab = ( elf->data + elf->ehdr->e_shoff +
+		   ( shdr->sh_link * elf->ehdr->e_shentsize ) );
+	syms = ( elf->data + symtab->sh_offset );
+	nsyms = ( symtab->sh_size / sizeof ( syms[0] ) );
+
+	/* Process each relocation */
+	rel = ( elf->data + shdr->sh_offset );
+	nrels = ( shdr->sh_size / stride );
+	for ( i = 0 ; i < nrels ; i++ ) {
+		process_reloc ( elf, shdr, syms, nsyms, rel, pe_reltab );
+		rel = ( ( ( const void * ) rel ) + stride );
+	}
+}
+
+/**
  * Create relocations section
  *
  * @v pe_header		PE file header
@@ -696,53 +817,60 @@ static void write_pe_file ( struct pe_header *pe_header,
 static void elf2pe ( const char *elf_name, const char *pe_name,
 		     struct options *opts ) {
 	char pe_name_tmp[ strlen ( pe_name ) + 1 ];
-	bfd *bfd;
-	asymbol **symtab;
-	asection *section;
-	arelent **reltab;
-	arelent **rel;
 	struct pe_relocs *pe_reltab = NULL;
 	struct pe_section *pe_sections = NULL;
 	struct pe_section **next_pe_section = &pe_sections;
 	struct pe_header pe_header;
+	struct elf_file elf;
+	const Elf_Shdr *shdr;
+	size_t offset;
+	unsigned int i;
 	FILE *pe;
 
 	/* Create a modifiable copy of the PE name */
 	memcpy ( pe_name_tmp, pe_name, sizeof ( pe_name_tmp ) );
 
-	/* Open the file */
-	bfd = open_input_bfd ( elf_name );
-	symtab = read_symtab ( bfd );
+	/* Read ELF file */
+	read_elf_file ( elf_name, &elf );
 
 	/* Initialise the PE header */
 	memcpy ( &pe_header, &efi_pe_header, sizeof ( pe_header ) );
-	pe_header.nt.OptionalHeader.AddressOfEntryPoint =
-		bfd_get_start_address ( bfd );
+	pe_header.nt.FileHeader.Machine = elf.machine->pe_machine;
+	pe_header.nt.OptionalHeader.AddressOfEntryPoint = elf.ehdr->e_entry;
 	pe_header.nt.OptionalHeader.Subsystem = opts->subsystem;
 
-	/* For each input section, build an output section and create
-	 * the appropriate relocation records
-	 */
-	for ( section = bfd->sections ; section ; section = section->next ) {
-		/* Discard non-allocatable sections */
-		if ( ! ( bfd_get_section_flags ( bfd, section ) & SEC_ALLOC ) )
-			continue;
-		/* Create output section */
-		*(next_pe_section) = process_section ( bfd, &pe_header,
-						       section );
-		next_pe_section = &(*next_pe_section)->next;
-		/* Add relocations from this section */
-		reltab = read_reltab ( bfd, symtab, section );
-		for ( rel = reltab ; *rel ; rel++ )
-			process_reloc ( bfd, section, *rel, &pe_reltab );
-		free ( reltab );
+	/* Process input sections */
+	for ( i = 0 ; i < elf.ehdr->e_shnum ; i++ ) {
+		offset = ( elf.ehdr->e_shoff + ( i * elf.ehdr->e_shentsize ) );
+		shdr = ( elf.data + offset );
+
+		/* Process section */
+		if ( shdr->sh_flags & SHF_ALLOC ) {
+
+			/* Create output section */
+			*(next_pe_section) = process_section ( &elf, shdr,
+							       &pe_header );
+			next_pe_section = &(*next_pe_section)->next;
+
+		} else if ( shdr->sh_type == SHT_REL ) {
+
+			/* Process .rel relocations */
+			process_relocs ( &elf, shdr, sizeof ( Elf_Rel ),
+					 &pe_reltab );
+
+		} else if ( shdr->sh_type == SHT_RELA ) {
+
+			/* Process .rela relocations */
+			process_relocs ( &elf, shdr, sizeof ( Elf_Rela ),
+					 &pe_reltab );
+		}
 	}
 
 	/* Create the .reloc section */
 	*(next_pe_section) = create_reloc_section ( &pe_header, pe_reltab );
 	next_pe_section = &(*next_pe_section)->next;
 
-	/* Create the .reloc section */
+	/* Create the .debug section */
 	*(next_pe_section) = create_debug_section ( &pe_header,
 						    basename ( pe_name_tmp ) );
 	next_pe_section = &(*next_pe_section)->next;
@@ -757,8 +885,8 @@ static void elf2pe ( const char *elf_name, const char *pe_name,
 	write_pe_file ( &pe_header, pe_sections, pe );
 	fclose ( pe );
 
-	/* Close BFD file */
-	bfd_close ( bfd );
+	/* Unmap ELF file */
+	munmap ( elf.data, elf.len );
 }
 
 /**
@@ -825,9 +953,6 @@ int main ( int argc, char **argv ) {
 	const char *infile;
 	const char *outfile;
 
-	/* Initialise libbfd */
-	bfd_init();
-
 	/* Parse command-line arguments */
 	infile_index = parse_options ( argc, argv, &opts );
 	if ( argc != ( infile_index + 2 ) ) {