btxld is a link editor for BTX (boot extender) clients, supporting ELF,

a.out, and binary formats.

6 files changed, 882 insertions, 0 deletions

diff --git a/usr.sbin/btxld/Makefile b/usr.sbin/btxld/Makefile
new file mode 100644
index 0000000..dd00a04
--- /dev/null
+++ b/usr.sbin/btxld/Makefile
@@ -0,0 +1,7 @@
+#	$Id:$
+
+PROG=	btxld
+SRCS=	btxld.c elfh.c
+MAN8=	btxld.8
+
+.include <bsd.prog.mk>
diff --git a/usr.sbin/btxld/btx.h b/usr.sbin/btxld/btx.h
new file mode 100644
index 0000000..4a31012
--- /dev/null
+++ b/usr.sbin/btxld/btx.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 1998 Robert Nordier
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *	$Id:$
+ */
+
+#ifndef _BTX_H_
+#define _BTX_H_
+
+#include <sys/types.h>
+
+#define BTX_PGSIZE	0x1000		/* Page size */
+#define BTX_PGBASE	0x5000		/* Start of page tables */
+#define BTX_MAXCWR	0x3bc		/* Max. btx_pgctl adjustment */
+
+/*
+ * BTX image header.
+ */
+struct btx_hdr {
+    uint8_t	btx_machid;		/* Machine ID */
+    uint8_t	btx_hdrsz;		/* Header size */
+    uint8_t	btx_magic[3];		/* Magic */
+    uint8_t	btx_majver;		/* Major version */
+    uint8_t	btx_minver;		/* Minor version */
+    uint8_t	btx_flags;		/* Flags */
+    uint16_t	btx_pgctl;		/* Paging control */
+    uint16_t	btx_textsz;		/* Text size */
+    uint32_t	btx_entry;		/* Client entry address */
+};
+
+/* btx_machid */
+#define BTX_I386	0xeb		/* Intel i386 or compatible */
+
+/* btx_magic */
+#define BTX_MAG0	'B'
+#define BTX_MAG1	'T'
+#define BTX_MAG2	'X'
+
+/* btx_flags */
+#define BTX_MAPONE	0x80		/* Start mapping at page 1 */
+
+#define BTX_MAPPED(btx) (((btx).btx_pgctl | (BTX_PGSIZE / 4 - 1)) + 1)
+#define BTX_ORIGIN(btx) (BTX_PGBASE + BTX_MAPPED(btx) * 4)
+#define BTX_ENTRY(btx)	(BTX_ORIGIN(btx) + 2 + (btx).btx_hdrsz)
+
+#endif /* !_BTX_H_ */
diff --git a/usr.sbin/btxld/btxld.8 b/usr.sbin/btxld/btxld.8
new file mode 100644
index 0000000..4267270
--- /dev/null
+++ b/usr.sbin/btxld/btxld.8
@@ -0,0 +1,97 @@
+.\" Copyright (c) 1998 Robert Nordier
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+.\" OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+.\" OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\"	$Id:$
+.\"
+.Dd September 12, 1998
+.Dt BTXLD 8
+.Os
+.Sh NAME
+.Nm btxld
+.Nd link editor for BTX clients
+.Sh SYNOPSIS
+.Nm btxld
+.Op Fl qv
+.Op Fl b Ar file
+.Op Fl E Ar address
+.Op Fl e Ar address
+.Op Fl f Ar format
+.Op Fl l Ar file
+.Op Fl o Ar filename
+.Op Fl P Ar page
+.Op Fl W Ar page
+.Ar file
+.Sh DESCRIPTION
+The
+.Nm
+utility binds the specified client executable together with a BTX
+loader program and the BTX kernel, and creates a composite object file
+suitable for loading during the boot process.
+.Pp
+The options are:
+.Bl -tag -width indent
+.It Fl q
+Quiet: inhibit warnings.
+.It Fl v
+Verbose: display information about the files processed.
+.It Fl b Ar file
+Specify the BTX kernel to be bound with the client.
+.It Fl E Ar address
+Set the client entry point.
+.It Fl e Ar address
+Set the BTX loader entry point.
+.It Fl f Ar format
+Specify the output format, where
+.Ar format
+is one of
+.Sq bin ,
+.Sq aout ,
+or
+.Sq elf .
+.It Fl l Ar file
+Specify the BTX loader to be bound with the client.
+.It Fl o Ar filename
+Name the output file.  The default is
+.Dq a.out .
+.It Fl P Ar page
+Specify the first page of the client's segment to be marked
+.Sq present ,
+where
+.Ar page
+may be 0 or 1.
+.It Fl W Ar page
+Specify the first page of the client's segment to be marked
+.Sq writable ,
+where
+.Ar page
+may be 0, and should not exceed the number of pages occupied by the
+combined .text and .data segments of the client image.
+.El
+.Sh SEE ALSO
+.Xr ld 1 ,
+.Xr boot 8
+.Sh DIAGNOSTICS
+Exit status is 0 on success and >0 on error.
+.Sh AUTHORS
+.An Robert Nordier Aq rnordier@FreeBSD.org .
diff --git a/usr.sbin/btxld/btxld.c b/usr.sbin/btxld/btxld.c
new file mode 100644
index 0000000..0e853e5
--- /dev/null
+++ b/usr.sbin/btxld/btxld.c
@@ -0,0 +1,550 @@
+/*
+ * Copyright (c) 1998 Robert Nordier
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef lint
+static const char rcsid[] =
+	"$Id:$";
+#endif /* not lint */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <a.out.h>
+#include <elf.h>
+
+#include "btx.h"
+#include "elfh.h"
+
+#define BTX_PATH		"/sys/boot/i386/btx"
+
+#define I_LDR	0		/* BTX loader */
+#define I_BTX	1		/* BTX kernel */
+#define I_CLNT	2		/* Client program */
+
+#define F_BIN	0		/* Binary */
+#define F_AOUT	1		/* ZMAGIC a.out */
+#define F_ELF	2		/* 32-bit ELF */
+#define F_CNT	3		/* Number of formats */
+
+#define IMPURE	1		/* Writable text */
+#define MAXU32	0xffffffff	/* Maximum unsigned 32-bit quantity */
+
+#define align(x, y) (((x) + (y) - 1) & ~((y) - 1))
+
+struct hdr {
+    unsigned fmt;		/* Format */
+    unsigned flags;		/* Bit flags */
+    unsigned size;		/* Size of file */
+    unsigned text;		/* Size of text segment */
+    unsigned data;		/* Size of data segment */
+    unsigned bss;		/* Size of bss segment */
+    unsigned org;		/* Program origin */
+    unsigned entry;		/* Program entry point */
+};
+
+static const char *const fmtlist[] = {"bin", "aout", "elf"};
+
+static const char binfo[] =
+    "kernel: ver=%u.%02u size=%x load=%x entry=%x map=%uM "
+    "pgctl=%x:%x\n";
+static const char cinfo[] =
+    "client: fmt=%s size=%x text=%x data=%x bss=%x entry=%x\n";
+static const char oinfo[] =
+    "output: fmt=%s size=%x text=%x data=%x org=%x entry=%x\n";
+
+static const char *lname =
+    BTX_PATH "/btxldr/btxldr";	/* BTX loader */
+static const char *bname =
+    BTX_PATH "/btx/btx";	/* BTX kernel */
+static const char *oname =
+    "a.out";			/* Output filename */
+
+static int ppage = -1;		/* First page present */
+static int wpage = -1;		/* First page writable */
+
+static unsigned format; 	/* Output format */
+
+static uint32_t centry; 	/* Client entry address */
+static uint32_t lentry; 	/* Loader entry address */
+
+static int quiet;		/* Inhibit warnings */
+static int verbose;		/* Display information */
+
+static const char *tname;	/* Temporary output file */
+static const char *fname;	/* Current input file */
+
+static void cleanup(void);
+static void btxld(const char *);
+static void getbtx(int, struct btx_hdr *);
+static void gethdr(int, struct hdr *);
+static void puthdr(int, struct hdr *);
+static void copy(int, int, size_t, off_t);
+static size_t readx(int, void *, size_t, off_t);
+static void writex(int, const void *, size_t);
+static void seekx(int, off_t);
+static unsigned optfmt(const char *);
+static uint32_t optaddr(const char *);
+static int optpage(const char *, int);
+static void Warn(const char *, const char *, ...);
+static void usage(void);
+
+/*
+ * A link editor for BTX clients.
+ */
+int
+main(int argc, char *argv[])
+{
+    int c;
+
+    while ((c = getopt(argc, argv, "qvb:E:e:f:l:o:P:W:")) != -1)
+	switch (c) {
+	case 'q':
+	    quiet = 1;
+	    break;
+	case 'v':
+	    verbose = 1;
+	    break;
+	case 'b':
+	    bname = optarg;
+	    break;
+	case 'E':
+	    centry = optaddr(optarg);
+	    break;
+	case 'e':
+	    lentry = optaddr(optarg);
+	    break;
+	case 'f':
+	    format = optfmt(optarg);
+	    break;
+	case 'l':
+	    lname = optarg;
+	    break;
+	case 'o':
+	    oname = optarg;
+	    break;
+	case 'P':
+	    ppage = optpage(optarg, 1);
+	    break;
+	case 'W':
+	    wpage = optpage(optarg, BTX_MAXCWR);
+	    break;
+	default:
+	    usage();
+	}
+    argc -= optind;
+    argv += optind;
+    if (argc != 1)
+	usage();
+    atexit(cleanup);
+    btxld(*argv);
+    return 0;
+}
+
+/*
+ * Clean up after errors.
+ */
+static void
+cleanup(void)
+{
+    if (tname)
+	remove(tname);
+}
+
+/*
+ * Read the input files; write the output file; display information.
+ */
+static void
+btxld(const char *iname)
+{
+    char name[FILENAME_MAX];
+    struct btx_hdr btx;
+    struct hdr ihdr, ohdr;
+    unsigned ldr_size, cwr;
+    int fdi[3], fdo, i;
+
+    for (i = I_LDR; i <= I_CLNT; i++) {
+	fname = i == I_LDR ? lname : i == I_BTX ? bname : iname;
+	if ((fdi[i] = open(fname, O_RDONLY)) == -1)
+	    err(2, "%s", fname);
+	switch (i) {
+	case I_LDR:
+	    gethdr(fdi[i], &ihdr);
+	    if (ihdr.fmt != F_BIN)
+		Warn(fname, "Loader format is %s; processing as %s",
+		     fmtlist[ihdr.fmt], fmtlist[F_BIN]);
+	    ldr_size = ihdr.size;
+	    break;
+	case I_BTX:
+	    getbtx(fdi[i], &btx);
+	    break;
+	case I_CLNT:
+	    gethdr(fdi[i], &ihdr);
+	    if (ihdr.org && ihdr.org != BTX_PGSIZE)
+		Warn(fname,
+		     "Client origin is 0x%x; expecting 0 or 0x%x",
+		     ihdr.org, BTX_PGSIZE);
+	}
+    }
+    memset(&ohdr, 0, sizeof(ohdr));
+    ohdr.fmt = format;
+    ohdr.text = ldr_size;
+    ohdr.data = btx.btx_textsz + ihdr.size;
+    ohdr.org = lentry;
+    ohdr.entry = lentry;
+    cwr = 0;
+    if (wpage > 0 || (wpage == -1 && !(ihdr.flags & IMPURE)))
+	if (wpage > 0)
+	    cwr = wpage;
+	else {
+	    cwr = howmany(ihdr.text, BTX_PGSIZE);
+	    if (cwr > BTX_MAXCWR)
+		cwr = BTX_MAXCWR;
+	}
+    if (ppage > 0 || (ppage && wpage && ihdr.org >= BTX_PGSIZE)) {
+	btx.btx_flags |= BTX_MAPONE;
+	if (!cwr)
+	    cwr++;
+    }
+    btx.btx_pgctl -= cwr;
+    if (snprintf(name, sizeof(name), "%s.tmp", oname) >= sizeof(name))
+	errx(2, "%s: Filename too long", oname);
+    if ((fdo = open(name, O_CREAT | O_TRUNC | O_WRONLY, 0666)) == -1)
+	err(2, "%s", name);
+    if (!(tname = strdup(name)))
+	err(2, NULL);
+    puthdr(fdo, &ohdr);
+    for (i = I_LDR; i <= I_CLNT; i++) {
+	fname = i == I_LDR ? lname : i == I_BTX ? bname : iname;
+	switch (i) {
+	case I_LDR:
+	    copy(fdi[i], fdo, ldr_size, 0);
+	    seekx(fdo, ohdr.size += ohdr.text);
+	    break;
+	case I_BTX:
+	    writex(fdo, &btx, sizeof(btx));
+	    copy(fdi[i], fdo, btx.btx_textsz - sizeof(btx),
+		 sizeof(btx));
+	    break;
+	case I_CLNT:
+	    copy(fdi[i], fdo, ihdr.size, 0);
+	    if (ftruncate(fdo, ohdr.size += ohdr.data))
+		err(2, "%s", tname);
+	}
+	if (close(fdi[i]))
+	    err(2, "%s", fname);
+    }
+    if (close(fdo))
+	err(2, "%s", tname);
+    if (rename(tname, oname))
+	err(2, "%s: Can't rename to %s", tname, oname);
+    tname = NULL;
+    if (verbose) {
+	printf(binfo, btx.btx_majver, btx.btx_minver, btx.btx_textsz,
+	       BTX_ORIGIN(btx), BTX_ENTRY(btx), BTX_MAPPED(btx) *
+	       BTX_PGSIZE / 0x100000, !!(btx.btx_flags & BTX_MAPONE),
+	       BTX_MAPPED(btx) - btx.btx_pgctl - BTX_PGBASE /
+	       BTX_PGSIZE - BTX_MAPPED(btx) * 4 / BTX_PGSIZE);
+	printf(cinfo, fmtlist[ihdr.fmt], ihdr.size, ihdr.text,
+	       ihdr.data, ihdr.bss, ihdr.entry);
+	printf(oinfo, fmtlist[ohdr.fmt], ohdr.size, ohdr.text,
+	       ohdr.data, ohdr.org, ohdr.entry);
+    }
+}
+
+/*
+ * Read BTX file header.
+ */
+static void
+getbtx(int fd, struct btx_hdr * btx)
+{
+    if (readx(fd, btx, sizeof(*btx), 0) != sizeof(*btx) ||
+	btx->btx_magic[0] != BTX_MAG0 ||
+	btx->btx_magic[1] != BTX_MAG1 ||
+	btx->btx_magic[2] != BTX_MAG2)
+	errx(1, "%s: Not a BTX kernel", fname);
+}
+
+/*
+ * Get file size and read a.out or ELF header.
+ */
+static void
+gethdr(int fd, struct hdr *hdr)
+{
+    struct stat sb;
+    const struct exec *ex;
+    const Elf32_Ehdr *ee;
+    const Elf32_Phdr *ep;
+    void *p;
+    unsigned fmt, x, n, i;
+
+    memset(hdr, 0, sizeof(*hdr));
+    if (fstat(fd, &sb))
+	err(2, "%s", fname);
+    if (sb.st_size > MAXU32)
+	errx(1, "%s: Too big", fname);
+    hdr->size = sb.st_size;
+    if ((p = mmap(NULL, hdr->size, PROT_READ, MAP_SHARED, fd,
+		  0)) == MAP_FAILED)
+	err(2, "%s", fname);
+    for (fmt = F_CNT - 1; !hdr->fmt && fmt; fmt--)
+	switch (fmt) {
+	case F_AOUT:
+	    ex = p;
+	    if (hdr->size >= sizeof(struct exec) && !N_BADMAG(*ex)) {
+		hdr->fmt = fmt;
+		x = N_GETMAGIC(*ex);
+		if (x == OMAGIC || x == NMAGIC) {
+		    if (x == NMAGIC)
+			Warn(fname, "Treating %s NMAGIC as OMAGIC",
+			     fmtlist[fmt]);
+		    hdr->flags |= IMPURE;
+		}
+		hdr->text = ex->a_text;
+		hdr->data = ex->a_data;
+		hdr->bss = ex->a_bss;
+		hdr->entry = ex->a_entry;
+		if (ex->a_entry >= BTX_PGSIZE)
+		    hdr->org = BTX_PGSIZE;
+	    }
+	    break;
+	case F_ELF:
+	    ee = p;
+	    if (hdr->size >= sizeof(Elf32_Ehdr) && IS_ELF(*ee)) {
+		hdr->fmt = fmt;
+		for (n = i = 0; i < ee->e_phnum; i++) {
+		    ep = (void *)((uint8_t *)p + ee->e_phoff +
+				  ee->e_phentsize * i);
+		    if (ep->p_type == PT_LOAD)
+			switch (n++) {
+			case 0:
+			    hdr->text = ep->p_filesz;
+			    hdr->org = ep->p_paddr;
+			    if (ep->p_flags & PF_W)
+				hdr->flags |= IMPURE;
+			    break;
+			case 1:
+			    hdr->data = ep->p_filesz;
+			    hdr->bss = ep->p_memsz - ep->p_filesz;
+			    break;
+			case 2:
+			    Warn(fname,
+				 "Ignoring extra %s PT_LOAD segments",
+				 fmtlist[fmt]);
+			}
+		}
+		hdr->entry = ee->e_entry;
+	    }
+	}
+    if (munmap(p, hdr->size))
+	err(2, "%s", fname);
+}
+
+/*
+ * Write a.out or ELF header.
+ */
+static void
+puthdr(int fd, struct hdr *hdr)
+{
+    struct exec ex;
+    struct elfh eh;
+
+    switch (hdr->fmt) {
+    case F_AOUT:
+	memset(&ex, 0, sizeof(ex));
+	N_SETMAGIC(ex, ZMAGIC, MID_ZERO, 0);
+	hdr->text = N_ALIGN(ex, hdr->text);
+	ex.a_text = hdr->text;
+	hdr->data = N_ALIGN(ex, hdr->data);
+	ex.a_data = hdr->data;
+	ex.a_entry = hdr->entry;
+	writex(fd, &ex, sizeof(ex));
+	hdr->size = N_ALIGN(ex, sizeof(ex));
+	seekx(fd, hdr->size);
+	break;
+    case F_ELF:
+	eh = elfhdr;
+	eh.e.e_entry = hdr->entry;
+	eh.p[0].p_vaddr = eh.p[0].p_paddr = hdr->org;
+	eh.p[0].p_filesz = eh.p[0].p_memsz = hdr->text;
+	eh.p[1].p_offset = eh.p[0].p_offset + eh.p[0].p_filesz;
+	eh.p[1].p_vaddr = eh.p[1].p_paddr = align(eh.p[0].p_paddr +
+						  eh.p[0].p_memsz, 4);
+	eh.p[1].p_filesz = eh.p[1].p_memsz = hdr->data;
+	eh.sh[2].sh_addr = eh.p[0].p_vaddr;
+	eh.sh[2].sh_offset = eh.p[0].p_offset;
+	eh.sh[2].sh_size = eh.p[0].p_filesz;
+	eh.sh[3].sh_addr = eh.p[1].p_vaddr;
+	eh.sh[3].sh_offset = eh.p[1].p_offset;
+	eh.sh[3].sh_size = eh.p[1].p_filesz;
+	writex(fd, &eh, sizeof(eh));
+	hdr->size = sizeof(eh);
+    }
+}
+
+/*
+ * Safe copy from input file to output file.
+ */
+static void
+copy(int fdi, int fdo, size_t nbyte, off_t offset)
+{
+    char buf[8192];
+    size_t n;
+
+    while (nbyte) {
+	if ((n = sizeof(buf)) > nbyte)
+	    n = nbyte;
+	if (readx(fdi, buf, n, offset) != n)
+	    errx(2, "%s: Short read", fname);
+	writex(fdo, buf, n);
+	nbyte -= n;
+	offset = -1;
+    }
+}
+
+/*
+ * Safe read from input file.
+ */
+static size_t
+readx(int fd, void *buf, size_t nbyte, off_t offset)
+{
+    ssize_t n;
+
+    if (offset != -1 && lseek(fd, offset, SEEK_SET) != offset)
+	err(2, "%s", fname);
+    if ((n = read(fd, buf, nbyte)) == -1)
+	err(2, "%s", fname);
+    return n;
+}
+
+/*
+ * Safe write to output file.
+ */
+static void
+writex(int fd, const void *buf, size_t nbyte)
+{
+    ssize_t n;
+
+    if ((n = write(fd, buf, nbyte)) == -1)
+	err(2, "%s", tname);
+    if (n != nbyte)
+	errx(2, "%s: Short write", tname);
+}
+
+/*
+ * Safe seek in output file.
+ */
+static void
+seekx(int fd, off_t offset)
+{
+    if (lseek(fd, offset, SEEK_SET) != offset)
+	err(2, "%s", tname);
+}
+
+/*
+ * Convert an option argument to a format code.
+ */
+static unsigned
+optfmt(const char *arg)
+{
+    unsigned i;
+
+    for (i = 0; i < F_CNT && strcmp(arg, fmtlist[i]); i++);
+    if (i == F_CNT)
+	errx(1, "%s: Unknown format", arg);
+    return i;
+}
+
+/*
+ * Convert an option argument to an address.
+ */
+static uint32_t
+optaddr(const char *arg)
+{
+    char *s;
+    unsigned long x;
+
+    errno = 0;
+    x = strtoul(arg, &s, 0);
+    if (errno || !*arg || *s || x > MAXU32)
+	errx(1, "%s: Illegal address", arg);
+    return x;
+}
+
+/*
+ * Convert an option argument to a page number.
+ */
+static int
+optpage(const char *arg, int hi)
+{
+    char *s;
+    long x;
+
+    errno = 0;
+    x = strtol(arg, &s, 0);
+    if (errno || !*arg || *s || x < 0 || x > hi)
+	errx(1, "%s: Illegal page number", arg);
+    return x;
+}
+
+/*
+ * Display a warning.
+ */
+static void
+Warn(const char *locus, const char *fmt, ...)
+{
+    va_list ap;
+    char *s;
+
+    if (!quiet) {
+	asprintf(&s, "%s: Warning: %s", locus, fmt);
+	va_start(ap, fmt);
+	vwarnx(s, ap);
+	va_end(ap);
+	free(s);
+    }
+}
+
+/*
+ * Display usage information.
+ */
+static void
+usage(void)
+{
+    fprintf(stderr, "%s\n%s\n",
+    "usage: btxld [-qv] [-b file] [-E address] [-e address] [-f format]",
+    "             [-l file] [-o filename] [-P page] [-W page] file");
+    exit(1);
+}
diff --git a/usr.sbin/btxld/elfh.c b/usr.sbin/btxld/elfh.c
new file mode 100644
index 0000000..c60f3b2
--- /dev/null
+++ b/usr.sbin/btxld/elfh.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 1998 Robert Nordier
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *	$Id:$
+ */
+
+#include <stddef.h>
+#include "elfh.h"
+
+#define SET_ME	0xeeeeeeee    /* filled in by btxld */
+
+/*
+ * ELF header template.
+ */
+const struct elfh elfhdr = {
+    {
+	{
+	    ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,     /* e_ident */
+	    ELFCLASS32, ELFDATA2LSB, EV_CURRENT, 0,
+	    'F', 'r', 'e', 'e', 'B', 'S', 'D', 0
+	},
+	ET_EXEC,				    /* e_type */
+	EM_386, 				    /* e_machine */
+	EV_CURRENT,				    /* e_version */
+	SET_ME, 				    /* e_entry */
+	offsetof(struct elfh, p),		    /* e_phoff */
+	offsetof(struct elfh, sh),		    /* e_shoff */
+	0,					    /* e_flags */
+	sizeof(elfhdr.e),			    /* e_ehsize */
+	sizeof(elfhdr.p[0]),			    /* e_phentsize */
+	sizeof(elfhdr.p) / sizeof(elfhdr.p[0]),     /* e_phnum */
+	sizeof(elfhdr.sh[0]),			    /* e_shentsize */
+	sizeof(elfhdr.sh) / sizeof(elfhdr.sh[0]),   /* e_shnum */
+	1					    /* e_shstrndx */
+    },
+    {
+	{
+	    PT_LOAD,				    /* p_type */
+	    sizeof(elfhdr),			    /* p_offset */
+	    SET_ME,				    /* p_vaddr */
+	    SET_ME,				    /* p_paddr */
+	    SET_ME,				    /* p_filesz */
+	    SET_ME,				    /* p_memsz */
+	    PF_R | PF_X,			    /* p_flags */
+	    0x1000				    /* p_align */
+	},
+	{
+	    PT_LOAD,				    /* p_type */
+	    SET_ME,				    /* p_offset */
+	    SET_ME,				    /* p_vaddr */
+	    SET_ME,				    /* p_paddr */
+	    SET_ME,				    /* p_filesz */
+	    SET_ME,				    /* p_memsz */
+	    PF_R | PF_W,			    /* p_flags */
+	    0x1000				    /* p_align */
+	}
+    },
+    {
+	{
+	    0, SHT_NULL, 0, 0, 0, 0, SHN_UNDEF, 0, 0, 0
+	},
+	{
+	    1,					    /* sh_name */
+	    SHT_STRTAB, 			    /* sh_type */
+	    0,					    /* sh_flags */
+	    0,					    /* sh_addr */
+	    offsetof(struct elfh, shstrtab),	    /* sh_offset */
+	    sizeof(elfhdr.shstrtab),		    /* sh_size */
+	    SHN_UNDEF,				    /* sh_link */
+	    0,					    /* sh_info */
+	    1,					    /* sh_addralign */
+	    0					    /* sh_entsize */
+	},
+	{
+	    0xb,				    /* sh_name */
+	    SHT_PROGBITS,			    /* sh_type */
+	    SHF_EXECINSTR | SHF_ALLOC,		    /* sh_flags */
+	    SET_ME,				    /* sh_addr */
+	    SET_ME,				    /* sh_offset */
+	    SET_ME,				    /* sh_size */
+	    SHN_UNDEF,				    /* sh_link */
+	    0,					    /* sh_info */
+	    4,					    /* sh_addralign */
+	    0					    /* sh_entsize */
+	},
+	{
+	    0x11,				    /* sh_name */
+	    SHT_PROGBITS,			    /* sh_type */
+	    SHF_ALLOC | SHF_WRITE,		    /* sh_flags */
+	    SET_ME,				    /* sh_addr */
+	    SET_ME,				    /* sh_offset */
+	    SET_ME,				    /* sh_size */
+	    SHN_UNDEF,				    /* sh_link */
+	    0,					    /* sh_info */
+	    4,					    /* sh_addralign */
+	    0					    /* sh_entsize */
+	}
+    },
+    "\0.shstrtab\0.text\0.data" 		    /* shstrtab */
+};
diff --git a/usr.sbin/btxld/elfh.h b/usr.sbin/btxld/elfh.h
new file mode 100644
index 0000000..f7a845a
--- /dev/null
+++ b/usr.sbin/btxld/elfh.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 1998 Robert Nordier
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *	$Id:$
+ */
+
+#include <elf.h>
+
+struct elfh {
+    Elf32_Ehdr e;		/* ELF header */
+    Elf32_Phdr p[2];		/* program header */
+    Elf32_Shdr sh[4];		/* section header */
+    char shstrtab[28];		/* section header string table */
+};
+
+const struct elfh elfhdr;	/* ELF header template */