585 lines
13 KiB
C
585 lines
13 KiB
C
/* $NetBSD: exec_elf.c,v 1.2 1995/06/30 02:57:20 christos Exp $ */
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/*
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* Copyright (c) 1994 Christos Zoulas
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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
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* are met:
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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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* 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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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/namei.h>
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#include <sys/vnode.h>
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#include <sys/exec.h>
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#include <sys/exec_elf.h>
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#include <sys/mman.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_map.h>
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#include <machine/cpu.h>
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#include <machine/reg.h>
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#include <machine/exec.h>
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#ifdef COMPAT_LINUX
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#include <compat/linux/linux_exec.h>
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#endif
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#ifdef COMPAT_SVR4
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#include <compat/svr4/svr4_exec.h>
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#endif
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int (*elf_probe_funcs[])() = {
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#ifdef COMPAT_SVR4
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svr4_elf_probe,
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#endif
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#ifdef COMPAT_LINUX
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linux_elf_probe
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#endif
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};
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static int elf_set_segment __P((struct exec_package *, u_long, u_long,
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int));
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static int elf_read_from __P((struct proc *, struct vnode *, u_long,
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caddr_t, int));
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static void elf_load_psection __P((struct exec_vmcmd_set *,
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struct vnode *, Elf32_Phdr *, u_long *, u_long *, int *));
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#define ELF_ALIGN(a, b) ((a) & ~((b) - 1))
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/*
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* Copy arguments onto the stack in the normal way, but add some
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* extra information in case of dynamic binding.
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*/
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void *
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elf_copyargs(pack, arginfo, stack, argp)
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struct exec_package *pack;
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struct ps_strings *arginfo;
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void *stack;
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void *argp;
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{
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char **cpp = stack;
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char *dp, *sp;
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size_t len;
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void *nullp = NULL;
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int argc = arginfo->ps_nargvstr;
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int envc = arginfo->ps_nenvstr;
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AuxInfo *a;
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struct elf_args *ap;
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if (copyout(&argc, cpp++, sizeof(argc)))
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return NULL;
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dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen);
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sp = argp;
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/* XXX don't copy them out, remap them! */
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arginfo->ps_argvstr = cpp; /* remember location of argv for later */
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for (; --argc >= 0; sp += len, dp += len)
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if (copyout(&dp, cpp++, sizeof(dp)) ||
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copyoutstr(sp, dp, ARG_MAX, &len))
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return NULL;
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if (copyout(&nullp, cpp++, sizeof(nullp)))
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return NULL;
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arginfo->ps_envstr = cpp; /* remember location of envp for later */
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for (; --envc >= 0; sp += len, dp += len)
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if (copyout(&dp, cpp++, sizeof(dp)) ||
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copyoutstr(sp, dp, ARG_MAX, &len))
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return NULL;
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if (copyout(&nullp, cpp++, sizeof(nullp)))
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return NULL;
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/*
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* Push extra arguments on the stack needed by dynamically
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* linked binaries
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*/
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a = (AuxInfo *) cpp;
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if ((ap = (struct elf_args *) pack->ep_emul_arg)) {
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a->au_id = AUX_phdr;
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a->au_v = ap->arg_phaddr;
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a++;
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a->au_id = AUX_phent;
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a->au_v = ap->arg_phentsize;
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a++;
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a->au_id = AUX_phnum;
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a->au_v = ap->arg_phnum;
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a++;
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a->au_id = AUX_pagesz;
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a->au_v = NBPG;
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a++;
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a->au_id = AUX_base;
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a->au_v = ap->arg_interp;
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a++;
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a->au_id = AUX_flags;
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a->au_v = 0;
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a++;
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a->au_id = AUX_entry;
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a->au_v = ap->arg_entry;
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a++;
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a->au_id = AUX_null;
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a->au_v = 0;
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a++;
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free((char *) ap, M_TEMP);
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}
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return a;
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}
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/*
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* elf_check_header():
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*
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* Check header for validity; return 0 of ok ENOEXEC if error
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*
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* XXX machine type needs to be moved to <machine/param.h> so
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* just one comparison can be done. Unfortunately, there is both
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* em_486 and em_386, so this would not work on the i386.
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*/
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int
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elf_check_header(eh, type)
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Elf32_Ehdr *eh;
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int type;
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{
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#ifdef sparc
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/* #$%@#$%@#$%! */
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# define memcmp bcmp
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#endif
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if (memcmp(eh->e_ident, Elf32_e_ident, Elf32_e_siz) != 0)
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return ENOEXEC;
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switch (eh->e_machine) {
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/* XXX */
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#ifdef i386
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case Elf32_em_386:
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case Elf32_em_486:
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#endif
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#ifdef sparc
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case Elf32_em_sparc:
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#endif
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break;
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default:
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return ENOEXEC;
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}
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if (eh->e_type != type)
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return ENOEXEC;
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return 0;
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}
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/*
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* elf_load_psection():
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*
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* Load a psection at the appropriate address
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*/
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static void
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elf_load_psection(vcset, vp, ph, addr, size, prot)
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struct exec_vmcmd_set *vcset;
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struct vnode *vp;
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Elf32_Phdr *ph;
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u_long *addr;
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u_long *size;
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int *prot;
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{
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u_long uaddr, msize, rm, rf;
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long diff, offset;
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/*
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* If the user specified an address, then we load there.
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*/
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if (*addr != ELF32_NO_ADDR) {
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if (ph->p_align > 1) {
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*addr = ELF_ALIGN(*addr + ph->p_align, ph->p_align);
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uaddr = ELF_ALIGN(ph->p_vaddr, ph->p_align);
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} else
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uaddr = ph->p_vaddr;
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diff = ph->p_vaddr - uaddr;
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} else {
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*addr = uaddr = ph->p_vaddr;
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if (ph->p_align > 1)
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*addr = ELF_ALIGN(uaddr, ph->p_align);
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diff = uaddr - *addr;
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}
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*prot |= (ph->p_flags & Elf32_pf_r) ? VM_PROT_READ : 0;
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*prot |= (ph->p_flags & Elf32_pf_w) ? VM_PROT_WRITE : 0;
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*prot |= (ph->p_flags & Elf32_pf_x) ? VM_PROT_EXECUTE : 0;
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offset = ph->p_offset - diff;
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*size = ph->p_filesz + diff;
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msize = ph->p_memsz + diff;
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NEW_VMCMD(vcset, vmcmd_map_readvn, *size, *addr, vp, offset, *prot);
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/*
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* Check if we need to extend the size of the segment
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*/
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rm = round_page(*addr + msize);
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rf = round_page(*addr + *size);
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if (rm != rf) {
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NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0, *prot);
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*size = msize;
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}
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}
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/*
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* elf_set_segment():
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*
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* Decide if the segment is text or data, depending on the protection
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* and set it appropriately
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*/
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static int
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elf_set_segment(epp, vaddr, size, prot)
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struct exec_package *epp;
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u_long vaddr;
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u_long size;
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int prot;
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{
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/*
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* Kludge: Unfortunately the current implementation of
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* exec package assumes a single text and data segment.
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* In Elf we can have more, but here we limit ourselves
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* to two and hope :-(
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* We also assume that the text is r-x, and data is rwx or rw-.
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*/
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switch (prot) {
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case (VM_PROT_READ | VM_PROT_EXECUTE):
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if (epp->ep_tsize != ELF32_NO_ADDR)
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return ENOEXEC;
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epp->ep_taddr = vaddr;
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epp->ep_tsize = size;
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break;
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case (VM_PROT_READ | VM_PROT_WRITE):
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case (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE):
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if (epp->ep_dsize != ELF32_NO_ADDR)
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return ENOEXEC;
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epp->ep_daddr = vaddr;
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epp->ep_dsize = size;
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break;
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default:
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return ENOEXEC;
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}
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return 0;
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}
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/*
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* elf_read_from():
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*
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* Read from vnode into buffer at offset.
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*/
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static int
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elf_read_from(p, vp, off, buf, size)
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struct vnode *vp;
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u_long off;
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struct proc *p;
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caddr_t buf;
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int size;
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{
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int error;
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int resid;
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if ((error = vn_rdwr(UIO_READ, vp, buf, size,
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off, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
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&resid, p)) != 0)
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return error;
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/*
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* See if we got all of it
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*/
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if (resid != 0)
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return error;
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return 0;
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}
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/*
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* elf_load_file():
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*
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* Load a file (interpreter/library) pointed to by path
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* [stolen from coff_load_shlib()]. Made slightly generic
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* so it might be used externally.
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*/
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int
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elf_load_file(p, path, vcset, entry, ap, last)
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struct proc *p;
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char *path;
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struct exec_vmcmd_set *vcset;
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u_long *entry;
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struct elf_args *ap;
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u_long *last;
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{
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int error, i;
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struct nameidata nd;
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Elf32_Ehdr eh;
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Elf32_Phdr *ph = NULL;
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u_long phsize;
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char *bp = NULL;
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u_long addr = *last;
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bp = path;
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/*
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* 1. open file
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* 2. read filehdr
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* 3. map text, data, and bss out of it using VM_*
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*/
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, p);
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if ((error = namei(&nd)) != 0) {
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return error;
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}
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if ((error = elf_read_from(p, nd.ni_vp, 0, (caddr_t) &eh,
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sizeof(eh))) != 0)
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goto bad;
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if ((error = elf_check_header(&eh, Elf32_et_dyn)) != 0)
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goto bad;
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phsize = eh.e_phnum * sizeof(Elf32_Phdr);
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ph = (Elf32_Phdr *) malloc(phsize, M_TEMP, M_WAITOK);
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if ((error = elf_read_from(p, nd.ni_vp, eh.e_phoff,
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(caddr_t) ph, phsize)) != 0)
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goto bad;
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/*
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* Load all the necessary sections
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*/
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for (i = 0; i < eh.e_phnum; i++) {
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u_long size = 0;
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int prot = 0;
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switch (ph[i].p_type) {
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case Elf32_pt_load:
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elf_load_psection(vcset, nd.ni_vp, &ph[i], &addr,
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&size, &prot);
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/* Assume that the text segment is r-x only */
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if ((prot & PROT_WRITE) == 0) {
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*entry = addr + eh.e_entry;
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ap->arg_interp = addr;
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}
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addr += size;
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break;
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case Elf32_pt_dynamic:
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case Elf32_pt_phdr:
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case Elf32_pt_note:
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break;
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default:
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break;
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}
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}
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bad:
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if (ph != NULL)
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free((char *) ph, M_TEMP);
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*last = addr;
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vrele(nd.ni_vp);
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return error;
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}
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/*
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* exec_elf_makecmds(): Prepare an Elf binary's exec package
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*
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* First, set of the various offsets/lengths in the exec package.
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*
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* Then, mark the text image busy (so it can be demand paged) or error
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* out if this is not possible. Finally, set up vmcmds for the
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* text, data, bss, and stack segments.
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*
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* XXX no demand paging (yet?)
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*/
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int
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exec_elf_makecmds(p, epp)
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struct proc *p;
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struct exec_package *epp;
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{
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Elf32_Ehdr *eh = epp->ep_hdr;
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Elf32_Phdr *ph, *pp;
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int error, i, n;
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char interp[MAXPATHLEN];
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u_long pos = 0, phsize;
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if (epp->ep_hdrvalid < sizeof(Elf32_Ehdr))
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return ENOEXEC;
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if (elf_check_header(eh, Elf32_et_exec))
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return ENOEXEC;
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/*
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* check if vnode is in open for writing, because we want to
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* demand-page out of it. if it is, don't do it, for various
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* reasons
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*/
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if (epp->ep_vp->v_writecount != 0) {
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#ifdef DIAGNOSTIC
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if (epp->ep_vp->v_flag & VTEXT)
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panic("exec: a VTEXT vnode has writecount != 0\n");
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#endif
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return ETXTBSY;
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}
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/*
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* Allocate space to hold all the program headers, and read them
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* from the file
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*/
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phsize = eh->e_phnum * sizeof(Elf32_Phdr);
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ph = (Elf32_Phdr *) malloc(phsize, M_TEMP, M_WAITOK);
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if ((error = elf_read_from(p, epp->ep_vp, eh->e_phoff,
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(caddr_t) ph, phsize)) != 0)
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goto bad;
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epp->ep_tsize = ELF32_NO_ADDR;
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epp->ep_dsize = ELF32_NO_ADDR;
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interp[0] = '\0';
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for (i = 0; i < eh->e_phnum; i++) {
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pp = &ph[i];
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if (pp->p_type == Elf32_pt_interp) {
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if (pp->p_filesz >= sizeof(interp))
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goto bad;
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if ((error = elf_read_from(p, epp->ep_vp, pp->p_offset,
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(caddr_t) interp, pp->p_filesz)) != 0)
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goto bad;
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break;
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}
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}
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/*
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* On the same architecture, we may be emulating different systems.
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* See which one will accept this executable. This currently only
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* applies to Linux and SVR4 on the i386.
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*
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* Probe functions would normally see if the interpreter (if any)
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* exists. Emulation packages may possibly replace the interpreter in
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* interp[] with a changed path (/emul/xxx/<path>), and also
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* set the ep_emul field in the exec package structure.
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*/
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if ((n = sizeof elf_probe_funcs / sizeof elf_probe_funcs[0])) {
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error = ENOEXEC;
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for (i = 0; i < n && error; i++)
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error = elf_probe_funcs[i](p, epp, interp, &pos);
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if (error)
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goto bad;
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}
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/*
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* Load all the necessary sections
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*/
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for (i = 0; i < eh->e_phnum; i++) {
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u_long addr = ELF32_NO_ADDR, size = 0;
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int prot = 0;
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pp = &ph[i];
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switch (ph[i].p_type) {
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case Elf32_pt_load:
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elf_load_psection(&epp->ep_vmcmds, epp->ep_vp,
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&ph[i], &addr, &size, &prot);
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if ((error = elf_set_segment(epp, addr, size,
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prot)) != 0)
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goto bad;
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break;
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case Elf32_pt_shlib:
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error = ENOEXEC;
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goto bad;
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case Elf32_pt_interp:
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/* Already did this one */
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case Elf32_pt_dynamic:
|
|
case Elf32_pt_phdr:
|
|
case Elf32_pt_note:
|
|
break;
|
|
|
|
default:
|
|
/*
|
|
* Not fatal, we don't need to understand everything
|
|
* :-)
|
|
*/
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check if we found a dynamically linked binary and arrange to load
|
|
* it's interpreter
|
|
*/
|
|
if (interp[0]) {
|
|
struct elf_args *ap;
|
|
|
|
ap = (struct elf_args *) malloc(sizeof(struct elf_args),
|
|
M_TEMP, M_WAITOK);
|
|
if ((error = elf_load_file(p, interp, &epp->ep_vmcmds,
|
|
&epp->ep_entry, ap, &pos)) != 0) {
|
|
free((char *) ap, M_TEMP);
|
|
goto bad;
|
|
}
|
|
/* Arrange to load the program headers. */
|
|
pos = ELF_ALIGN(pos + NBPG, NBPG);
|
|
ap->arg_phaddr = pos;
|
|
NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, phsize,
|
|
pos, epp->ep_vp, eh->e_phoff,
|
|
VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE);
|
|
pos += phsize;
|
|
|
|
ap->arg_phentsize = eh->e_phentsize;
|
|
ap->arg_phnum = eh->e_phnum;
|
|
ap->arg_entry = eh->e_entry;
|
|
|
|
epp->ep_emul_arg = ap;
|
|
} else
|
|
epp->ep_entry = eh->e_entry;
|
|
|
|
free((char *) ph, M_TEMP);
|
|
epp->ep_vp->v_flag |= VTEXT;
|
|
return exec_aout_setup_stack(p, epp);
|
|
|
|
bad:
|
|
free((char *) ph, M_TEMP);
|
|
kill_vmcmds(&epp->ep_vmcmds);
|
|
return ENOEXEC;
|
|
}
|