Return to loadfile.c CVS log

Up to [cvs.NetBSD.org] / src / sys / lib / libsa

When loading ELF, zero out:
The e_shstrndx field in the ELF header, since we don't load .shstrtab.
The sh_name field in each section header, for the same reason.
The sh_offset field for any section we don't load.

This means the kernel has some chance of knowing what it's being given.  It
also means that the behaviour of old kernels with new loaders should be
deterministic (if not terribly useful: they still can't find the symbol
table).

/* $NetBSD: loadfile.c,v 1.17 2001/07/31 22:11:57 bjh21 Exp $ */

/*-
 * Copyright (c) 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center and by Christos Zoulas.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)boot.c	8.1 (Berkeley) 6/10/93
 */

#ifdef _STANDALONE
#include <lib/libsa/stand.h>
#include <lib/libkern/libkern.h>
#else
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <err.h>
#endif

#include <sys/param.h>
#include <sys/exec.h>

#include "loadfile.h"

#ifdef BOOT_ECOFF
#include <sys/exec_ecoff.h>
static int coff_exec __P((int, struct ecoff_exechdr *, u_long *, int));
#endif
#ifdef BOOT_ELF
#include <sys/exec_elf.h>
static int elf_exec __P((int, Elf_Ehdr *, u_long *, int));
#endif
#ifdef BOOT_AOUT
#include <sys/exec_aout.h>
static int aout_exec __P((int, struct exec *, u_long *, int));
#endif

/*
 * Open 'filename', read in program and and return 0 if ok 1 on error.
 * Fill in marks
 */
int
loadfile(fname, marks, flags)
	const char *fname;
	u_long *marks;
	int flags;
{
	union {
#ifdef BOOT_ECOFF
		struct ecoff_exechdr coff;
#endif
#ifdef BOOT_ELF
		Elf_Ehdr elf;
#endif
#ifdef BOOT_AOUT
		struct exec aout;
#endif
		
	} hdr;
	ssize_t nr;
	int fd, rval;

	/* Open the file. */
	if ((fd = open(fname, 0)) < 0) {
		WARN(("open %s", fname ? fname : "<default>"));
		return -1;
	}

	/* Read the exec header. */
	if ((nr = read(fd, &hdr, sizeof(hdr))) != sizeof(hdr)) {
		WARN(("read header"));
		goto err;
	}

#ifdef BOOT_ECOFF
	if (!ECOFF_BADMAG(&hdr.coff)) {
		rval = coff_exec(fd, &hdr.coff, marks, flags);
	} else
#endif
#ifdef BOOT_ELF
	if (memcmp(hdr.elf.e_ident, ELFMAG, SELFMAG) == 0 &&
	    hdr.elf.e_ident[EI_CLASS] == ELFCLASS) {
		rval = elf_exec(fd, &hdr.elf, marks, flags);
	} else
#endif
#ifdef BOOT_AOUT
	if (OKMAGIC(N_GETMAGIC(hdr.aout))
#ifndef NO_MID_CHECK
	    && N_GETMID(hdr.aout) == MID_MACHINE
#endif
	    ) {
		rval = aout_exec(fd, &hdr.aout, marks, flags);
	} else
#endif
	{
		rval = 1;
		errno = EFTYPE;
		WARN(("%s", fname ? fname : "<default>"));
	}

	if (rval == 0) {
		PROGRESS(("=0x%lx\n", marks[MARK_END] - marks[MARK_START]));
		return fd;
	}
err:
	(void)close(fd);
	return -1;
}

#ifdef BOOT_ECOFF
static int
coff_exec(fd, coff, marks, flags)
	int fd;
	struct ecoff_exechdr *coff;
	u_long *marks;
	int flags;
{
	paddr_t offset = marks[MARK_START];
	paddr_t minp = ~0, maxp = 0, pos;

	/* Read in text. */
	if (lseek(fd, ECOFF_TXTOFF(coff), SEEK_SET) == -1)  {
		WARN(("lseek text"));
		return 1;
	}

	if (coff->a.tsize != 0) {
		if (flags & LOAD_TEXT) {
			PROGRESS(("%lu", coff->a.tsize));
			if (READ(fd, coff->a.text_start, coff->a.tsize) !=
			    coff->a.tsize) {
				return 1;
			}
		}
		else {
			if (lseek(fd, coff->a.tsize, SEEK_CUR) == -1) {
				WARN(("read text"));
				return 1;
			}
		}
		if (flags & (COUNT_TEXT|LOAD_TEXT)) {
			pos = coff->a.text_start;
			if (minp > pos)
				minp = pos;
			pos += coff->a.tsize;
			if (maxp < pos)
				maxp = pos;
		}
	}

	/* Read in data. */
	if (coff->a.dsize != 0) {
		if (flags & LOAD_DATA) {
			PROGRESS(("+%lu", coff->a.dsize));
			if (READ(fd, coff->a.data_start, coff->a.dsize) !=
			    coff->a.dsize) {
				WARN(("read data"));
				return 1;
			}
		}
		if (flags & (COUNT_DATA|LOAD_DATA)) {
			pos = coff->a.data_start;
			if (minp > pos)
				minp = pos;
			pos += coff->a.dsize;
			if (maxp < pos)
				maxp = pos;
		}
	}

	/* Zero out bss. */
	if (coff->a.bsize != 0) {
		if (flags & LOAD_BSS) {
			PROGRESS(("+%lu", coff->a.bsize));
			BZERO(coff->a.bss_start, coff->a.bsize);
		}
		if (flags & (COUNT_BSS|LOAD_BSS)) {
			pos = coff->a.bss_start;
			if (minp > pos)
				minp = pos;
			pos = coff->a.bsize;
			if (maxp < pos)
				maxp = pos;
		}
	}

	marks[MARK_START] = LOADADDR(minp);
	marks[MARK_ENTRY] = LOADADDR(coff->a.entry);
	marks[MARK_NSYM] = 1;	/* XXX: Kernel needs >= 0 */
	marks[MARK_SYM] = LOADADDR(maxp);
	marks[MARK_END] = LOADADDR(maxp);
	return 0;
}
#endif /* BOOT_ECOFF */

#ifdef BOOT_ELF
static int
elf_exec(fd, elf, marks, flags)
	int fd;
	Elf_Ehdr *elf;
	u_long *marks;
	int flags;
{
	Elf_Shdr *shp;
	int i, j;
	size_t sz;
	int first;
	paddr_t minp = ~0, maxp = 0, pos = 0;
	paddr_t offset = marks[MARK_START], shpp, elfp = NULL;

	for (first = 1, i = 0; i < elf->e_phnum; i++) {
		Elf_Phdr phdr;
		if (lseek(fd, elf->e_phoff + sizeof(phdr) * i, SEEK_SET)
		    == -1)  {
			WARN(("lseek phdr"));
			return 1;
		}
		if (read(fd, (void *)&phdr, sizeof(phdr)) != sizeof(phdr)) {
			WARN(("read phdr"));
			return 1;
		}
		if (phdr.p_type != PT_LOAD ||
		    (phdr.p_flags & (PF_W|PF_X)) == 0)
			continue;

#define IS_TEXT(p)	(p.p_flags & PF_X)
#define IS_DATA(p)	(p.p_flags & PF_W)
#define IS_BSS(p)	(p.p_filesz < p.p_memsz)
		/*
		 * XXX: Assume first address is lowest
		 */
		if ((IS_TEXT(phdr) && (flags & LOAD_TEXT)) ||
		    (IS_DATA(phdr) && (flags & LOAD_DATA))) {

			/* Read in segment. */
			PROGRESS(("%s%lu", first ? "" : "+",
			    (u_long)phdr.p_filesz));

			if (lseek(fd, phdr.p_offset, SEEK_SET) == -1)  {
				WARN(("lseek text"));
				return 1;
			}
			if (READ(fd, phdr.p_vaddr, phdr.p_filesz) !=
			    phdr.p_filesz) {
				WARN(("read text"));
				return 1;
			}
			first = 0;

		}
		if ((IS_TEXT(phdr) && (flags & (LOAD_TEXT|COUNT_TEXT))) ||
		    (IS_DATA(phdr) && (flags & (LOAD_DATA|COUNT_TEXT)))) {
			pos = phdr.p_vaddr;
			if (minp > pos)
				minp = pos;
			pos += phdr.p_filesz;
			if (maxp < pos)
				maxp = pos;
		}

		/* Zero out bss. */
		if (IS_BSS(phdr) && (flags & LOAD_BSS)) {
			PROGRESS(("+%lu",
			    (u_long)(phdr.p_memsz - phdr.p_filesz)));
			BZERO((phdr.p_vaddr + phdr.p_filesz),
			    phdr.p_memsz - phdr.p_filesz);
		}
		if (IS_BSS(phdr) && (flags & (LOAD_BSS|COUNT_BSS))) {
			pos += phdr.p_memsz - phdr.p_filesz;
			if (maxp < pos)
				maxp = pos;
		}
	}

	/*
	 * Copy the ELF and section headers.
	 */
	maxp = roundup(maxp, sizeof(long));
	if (flags & (LOAD_HDR|COUNT_HDR)) {
		elfp = maxp;
		maxp += sizeof(Elf_Ehdr);
	}

	if (flags & (LOAD_SYM|COUNT_SYM)) {
		if (lseek(fd, elf->e_shoff, SEEK_SET) == -1)  {
			WARN(("lseek section headers"));
			return 1;
		}
		sz = elf->e_shnum * sizeof(Elf_Shdr);

		shp = ALLOC(sz);

		if (read(fd, shp, sz) != sz) {
			WARN(("read section headers"));
			return 1;
		}

		shpp = maxp;
		maxp += roundup(sz, sizeof(long));

		/*
		 * Now load the symbol sections themselves.  Make sure
		 * the sections are aligned. Don't bother with any
		 * string table that isn't referenced by a symbol
		 * table.
		 */
		for (first = 1, i = 0; i < elf->e_shnum; i++) {
			switch (shp[i].sh_type) {
			case SHT_STRTAB:
				for (j = 0; j < elf->e_shnum; j++)
					if (shp[j].sh_type == SHT_SYMTAB &&
					    shp[j].sh_link == i)
						goto havesym;
				/* FALLTHROUGH */
			default:
				/* Not loading this, so zero out the offset. */
				shp[i].sh_offset = 0;
				break;
			havesym:
			case SHT_SYMTAB:
				if (flags & LOAD_SYM) {
					PROGRESS(("%s%ld", first ? " [" : "+",
					    (u_long)shp[i].sh_size));
					if (lseek(fd, shp[i].sh_offset,
					    SEEK_SET) == -1) {
						WARN(("lseek symbols"));
						FREE(shp, sz);
						return 1;
					}
					if (READ(fd, maxp, shp[i].sh_size) !=
					    shp[i].sh_size) {
						WARN(("read symbols"));
						FREE(shp, sz);
						return 1;
					}
				}
				shp[i].sh_offset = maxp - elfp;
				maxp += roundup(shp[i].sh_size,
				    sizeof(long));
				first = 0;
			}
			/* Since we don't load .shstrtab, zero the name. */
			shp[i].sh_name = 0;
		}
		if (flags & LOAD_SYM) {
			BCOPY(shp, shpp, sz);

			if (first == 0)
				PROGRESS(("]"));
		}
		FREE(shp, sz);
	}

	/*
	 * Frob the copied ELF header to give information relative
	 * to elfp.
	 */
	if (flags & LOAD_HDR) {
		elf->e_phoff = 0;
		elf->e_shoff = sizeof(Elf_Ehdr);
		elf->e_phentsize = 0;
		elf->e_phnum = 0;
		elf->e_shstrndx = SHN_UNDEF;
		BCOPY(elf, elfp, sizeof(*elf));
	}

	marks[MARK_START] = LOADADDR(minp);
	marks[MARK_ENTRY] = LOADADDR(elf->e_entry);
	/*
	 * Since there can be more than one symbol section in the code
	 * and we need to find strtab too in order to do anything
	 * useful with the symbols, we just pass the whole elf
	 * header back and we let the kernel debugger find the
	 * location and number of symbols by itself.
	 */
	marks[MARK_NSYM] = 1;	/* XXX: Kernel needs >= 0 */
	marks[MARK_SYM] = LOADADDR(elfp);
	marks[MARK_END] = LOADADDR(maxp);
	return 0;
}
#endif /* BOOT_ELF */

#ifdef BOOT_AOUT
static int
aout_exec(fd, x, marks, flags)
	int fd;
	struct exec *x;
	u_long *marks;
	int flags;
{
	u_long entry = x->a_entry;
	paddr_t aoutp = 0;
	paddr_t minp, maxp;
	int cc;
	paddr_t offset = marks[MARK_START];
	u_long magic = N_GETMAGIC(*x);
	int sub;

	/* In OMAGIC and NMAGIC, exec header isn't part of text segment */
	if (magic == OMAGIC || magic == NMAGIC)
		sub = 0;
	else
		sub = sizeof(*x);
	
	minp = maxp = ALIGNENTRY(entry);

	if (lseek(fd, sizeof(*x), SEEK_SET) == -1)  {
		WARN(("lseek text"));
		return 1;
	}

	/*
	 * Leave a copy of the exec header before the text.
	 * The kernel may use this to verify that the
	 * symbols were loaded by this boot program.
	 */
	if (magic == OMAGIC || magic == NMAGIC) {
		if (flags & LOAD_HDR && maxp >= sizeof(*x))
			BCOPY(x, maxp - sizeof(*x), sizeof(*x));
	}
	else {
		if (flags & LOAD_HDR)
			BCOPY(x, maxp, sizeof(*x));
		if (flags & (LOAD_HDR|COUNT_HDR))
			maxp += sizeof(*x);
	}

	/*
	 * Read in the text segment.
	 */
	if (flags & LOAD_TEXT) {
		PROGRESS(("%ld", x->a_text));

		if (READ(fd, maxp, x->a_text - sub) != x->a_text - sub) {
			WARN(("read text"));
			return 1;
		}
	} else {
		if (lseek(fd, x->a_text - sub, SEEK_CUR) == -1) {
			WARN(("seek text"));
			return 1;
		}
	}
	if (flags & (LOAD_TEXT|COUNT_TEXT))
		maxp += x->a_text - sub;

	/*
	 * Provide alignment if required
	 */
	if (magic == ZMAGIC || magic == NMAGIC) {
		int size = -(unsigned int)maxp & (__LDPGSZ - 1);

		if (flags & LOAD_TEXTA) {
			PROGRESS(("/%d", size));
			BZERO(maxp, size);
		}

		if (flags & (LOAD_TEXTA|COUNT_TEXTA))
			maxp += size;
	}

	/*
	 * Read in the data segment.
	 */
	if (flags & LOAD_DATA) {
		PROGRESS(("+%ld", x->a_data));

		if (READ(fd, maxp, x->a_data) != x->a_data) {
			WARN(("read data"));
			return 1;
		}
	}
	else {
		if (lseek(fd, x->a_data, SEEK_CUR) == -1) {
			WARN(("seek data"));
			return 1;
		}
	}
	if (flags & (LOAD_DATA|COUNT_DATA))
		maxp += x->a_data;

	/*
	 * Zero out the BSS section.
	 * (Kernel doesn't care, but do it anyway.)
	 */
	if (flags & LOAD_BSS) {
		PROGRESS(("+%ld", x->a_bss));

		BZERO(maxp, x->a_bss);
	}

	if (flags & (LOAD_BSS|COUNT_BSS))
		maxp += x->a_bss;

	/*
	 * Read in the symbol table and strings.
	 * (Always set the symtab size word.)
	 */
	if (flags & LOAD_SYM)
		BCOPY(&x->a_syms, maxp, sizeof(x->a_syms));

	if (flags & (LOAD_SYM|COUNT_SYM)) {
		maxp += sizeof(x->a_syms);
		aoutp = maxp;
	}

	if (x->a_syms > 0) {
		/* Symbol table and string table length word. */

		if (flags & LOAD_SYM) {
			PROGRESS(("+[%ld", x->a_syms));

			if (READ(fd, maxp, x->a_syms) != x->a_syms) {
				WARN(("read symbols"));
				return 1;
			}
		} else  {
			if (lseek(fd, x->a_syms, SEEK_CUR) == -1) {
				WARN(("seek symbols"));
				return 1;
			}
		}
		if (flags & (LOAD_SYM|COUNT_SYM))
			maxp += x->a_syms;

		if (read(fd, &cc, sizeof(cc)) != sizeof(cc)) {
			WARN(("read string table"));
			return 1;
		}

		if (flags & LOAD_SYM) {
			BCOPY(&cc, maxp, sizeof(cc));

			/* String table. Length word includes itself. */

			PROGRESS(("+%d]", cc));
		}
		if (flags & (LOAD_SYM|COUNT_SYM))
			maxp += sizeof(cc);

		cc -= sizeof(int);
		if (cc <= 0) {
			WARN(("symbol table too short"));
			return 1;
		}

		if (flags & LOAD_SYM) {
			if (READ(fd, maxp, cc) != cc) {
				WARN(("read strings"));
				return 1;
			}
		} else {
			if (lseek(fd, cc, SEEK_CUR) == -1) {
				WARN(("seek strings"));
				return 1;
			}
		}
		if (flags & (LOAD_SYM|COUNT_SYM))
			maxp += cc;
	}

	marks[MARK_START] = LOADADDR(minp);
	marks[MARK_ENTRY] = LOADADDR(entry);
	marks[MARK_NSYM] = x->a_syms;
	marks[MARK_SYM] = LOADADDR(aoutp);
	marks[MARK_END] = LOADADDR(maxp);
	return 0;
}
#endif /* BOOT_AOUT */