NetBSD/sys/kern/exec_elf32.c

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/* $NetBSD: exec_elf32.c,v 1.22 1996/12/17 22:04:20 cgd Exp $ */
/*
* Copyright (c) 1996 Christopher G. Demetriou
* Copyright (c) 1994 Christos Zoulas
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
/* If not included by exec_elf64.c, ELFSIZE won't be defined. */
#ifndef ELFSIZE
#define ELFSIZE 32
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/exec.h>
#include <sys/exec_elf.h>
#include <sys/fcntl.h>
#include <sys/syscall.h>
#include <sys/signalvar.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_map.h>
#include <machine/cpu.h>
#include <machine/reg.h>
#ifdef COMPAT_LINUX
#include <compat/linux/linux_exec.h>
#endif
#ifdef COMPAT_SVR4
#include <compat/svr4/svr4_exec.h>
#endif
#define CONCAT(x,y) __CONCAT(x,y)
#define ELFNAME(x) CONCAT(elf,CONCAT(ELFSIZE,CONCAT(_,x)))
#define ELFNAME2(x,y) CONCAT(x,CONCAT(_elf,CONCAT(ELFSIZE,CONCAT(_,y))))
#define ELFNAMEEND(x) CONCAT(x,CONCAT(_elf,ELFSIZE))
#define ELFDEFNNAME(x) CONCAT(ELF,CONCAT(ELFSIZE,CONCAT(_,x)))
1996-02-09 21:59:18 +03:00
int ELFNAME(check_header) __P((Elf_Ehdr *, int));
int ELFNAME(load_file) __P((struct proc *, struct exec_package *, char *,
struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *));
void ELFNAME(load_psection) __P((struct exec_vmcmd_set *, struct vnode *,
Elf_Phdr *, Elf_Addr *, u_long *, int *));
extern char sigcode[], esigcode[];
#ifdef SYSCALL_DEBUG
extern char *syscallnames[];
#endif
struct emul ELFNAMEEND(emul_netbsd) = {
"netbsd",
NULL,
sendsig,
SYS_syscall,
SYS_MAXSYSCALL,
sysent,
#ifdef SYSCALL_DEBUG
syscallnames,
#else
NULL,
#endif
ELF_AUX_ENTRIES * sizeof(AuxInfo),
ELFNAME(copyargs),
setregs,
sigcode,
esigcode,
};
int (*ELFNAME(probe_funcs)[]) __P((struct proc *, struct exec_package *,
Elf_Ehdr *, char *, Elf_Addr *)) = {
#if defined(COMPAT_SVR4) && (ELFSIZE == 32)
ELFNAME2(svr4,probe), /* XXX not 64-bit safe */
#endif
#if defined(COMPAT_LINUX) && (ELFSIZE == 32)
ELFNAME2(linux,probe), /* XXX not 64-bit safe */
#endif
};
/* round up and down to page boundaries. */
#define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1))
#define ELF_TRUNC(a, b) ((a) & ~((b) - 1))
/*
* Copy arguments onto the stack in the normal way, but add some
* extra information in case of dynamic binding.
*/
void *
ELFNAME(copyargs)(pack, arginfo, stack, argp)
struct exec_package *pack;
struct ps_strings *arginfo;
void *stack;
void *argp;
{
size_t len;
AuxInfo ai[ELF_AUX_ENTRIES], *a;
struct elf_args *ap;
stack = copyargs(pack, arginfo, stack, argp);
if (!stack)
return NULL;
a = ai;
/*
* Push extra arguments on the stack needed by dynamically
* linked binaries
*/
if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
a->au_id = AUX_phdr;
a->au_v = ap->arg_phaddr;
a++;
a->au_id = AUX_phent;
a->au_v = ap->arg_phentsize;
a++;
a->au_id = AUX_phnum;
a->au_v = ap->arg_phnum;
a++;
a->au_id = AUX_pagesz;
a->au_v = NBPG;
a++;
a->au_id = AUX_base;
a->au_v = ap->arg_interp;
a++;
a->au_id = AUX_flags;
a->au_v = 0;
a++;
a->au_id = AUX_entry;
a->au_v = ap->arg_entry;
a++;
free((char *)ap, M_TEMP);
pack->ep_emul_arg = NULL;
}
a->au_id = AUX_null;
a->au_v = 0;
a++;
len = (a - ai) * sizeof (AuxInfo);
if (copyout(ai, stack, len))
return NULL;
stack += len;
return stack;
}
/*
* elf_check_header():
*
* Check header for validity; return 0 of ok ENOEXEC if error
*/
int
ELFNAME(check_header)(eh, type)
Elf_Ehdr *eh;
int type;
{
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if (bcmp(eh->e_ident, Elf_e_ident, Elf_e_siz) != 0)
return ENOEXEC;
switch (eh->e_machine) {
ELFDEFNNAME(MACHDEP_ID_CASES)
default:
return ENOEXEC;
}
if (eh->e_type != type)
return ENOEXEC;
return 0;
}
/*
* elf_load_psection():
*
* Load a psection at the appropriate address
*/
void
ELFNAME(load_psection)(vcset, vp, ph, addr, size, prot)
struct exec_vmcmd_set *vcset;
struct vnode *vp;
Elf_Phdr *ph;
Elf_Addr *addr;
u_long *size;
int *prot;
{
u_long uaddr, msize, psize, rm, rf;
long diff, offset;
/*
* If the user specified an address, then we load there.
*/
if (*addr != ELFDEFNNAME(NO_ADDR)) {
if (ph->p_align > 1) {
*addr = ELF_ROUND(*addr, ph->p_align);
uaddr = ELF_TRUNC(ph->p_vaddr, ph->p_align);
} else
uaddr = ph->p_vaddr;
diff = ph->p_vaddr - uaddr;
} else {
*addr = uaddr = ph->p_vaddr;
if (ph->p_align > 1)
*addr = ELF_TRUNC(uaddr, ph->p_align);
diff = uaddr - *addr;
}
*prot |= (ph->p_flags & Elf_pf_r) ? VM_PROT_READ : 0;
*prot |= (ph->p_flags & Elf_pf_w) ? VM_PROT_WRITE : 0;
*prot |= (ph->p_flags & Elf_pf_x) ? VM_PROT_EXECUTE : 0;
offset = ph->p_offset - diff;
*size = ph->p_filesz + diff;
msize = ph->p_memsz + diff;
psize = round_page(*size);
if ((ph->p_flags & Elf_pf_w) != 0) {
/*
* Because the pagedvn pager can't handle zero fill of the last
* data page if it's not page aligned we map the last page
* readvn.
*/
psize = trunc_page(*size);
NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp,
offset, *prot);
if(psize != *size)
NEW_VMCMD(vcset, vmcmd_map_readvn, *size - psize,
*addr + psize, vp, offset + psize, *prot);
} else
NEW_VMCMD(vcset, vmcmd_map_pagedvn, psize, *addr, vp,
offset, *prot);
/*
* Check if we need to extend the size of the segment
*/
rm = round_page(*addr + msize);
rf = round_page(*addr + *size);
if (rm != rf) {
NEW_VMCMD(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
0, *prot);
*size = msize;
}
}
/*
* elf_read_from():
*
* Read from vnode into buffer at offset.
*/
int
ELFNAME(read_from)(p, vp, off, buf, size)
struct vnode *vp;
u_long off;
struct proc *p;
caddr_t buf;
int size;
{
int error;
int resid;
if ((error = vn_rdwr(UIO_READ, vp, buf, size, off, UIO_SYSSPACE,
0, p->p_ucred, &resid, p)) != 0)
return error;
/*
* See if we got all of it
*/
if (resid != 0)
return ENOEXEC;
return 0;
}
/*
* elf_load_file():
*
* Load a file (interpreter/library) pointed to by path
* [stolen from coff_load_shlib()]. Made slightly generic
* so it might be used externally.
*/
int
ELFNAME(load_file)(p, epp, path, vcset, entry, ap, last)
struct proc *p;
struct exec_package *epp;
char *path;
struct exec_vmcmd_set *vcset;
u_long *entry;
struct elf_args *ap;
Elf_Addr *last;
{
int error, i;
struct nameidata nd;
struct vnode *vp;
struct vattr attr;
Elf_Ehdr eh;
Elf_Phdr *ph = NULL;
u_long phsize;
char *bp = NULL;
Elf_Addr addr = *last;
bp = path;
/*
* 1. open file
* 2. read filehdr
* 3. map text, data, and bss out of it using VM_*
*/
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
if ((error = namei(&nd)) != 0)
return error;
vp = nd.ni_vp;
/* check for regular file */
if (vp->v_type != VREG) {
error = EACCES;
goto badunlock;
}
/* get attributes */
if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
goto badunlock;
/*
* Check mount point. Though we're not trying to exec this binary,
* we will be executing code from it, so if the mount point
* disallows execution or set-id-ness, we punt or kill the set-id.
*/
if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
error = EACCES;
goto badunlock;
}
if (vp->v_mount->mnt_flag & MNT_NOSUID)
epp->ep_vap->va_mode &= ~(VSUID | VSGID);
/*
* Similarly, if it's not marked as executable, we don't allow
* it to be used. For root we have to see if any exec bit on.
*/
if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
goto badunlock;
if ((attr.va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) {
error = EACCES;
goto badunlock;
}
#ifdef notyet /* XXX cgd 960926 */
XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
#endif
VOP_UNLOCK(vp);
if ((error = ELFNAME(read_from)(p, vp, 0, (caddr_t) &eh,
sizeof(eh))) != 0)
goto bad;
if ((error = ELFNAME(check_header)(&eh, Elf_et_dyn)) != 0)
goto bad;
phsize = eh.e_phnum * sizeof(Elf_Phdr);
ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
if ((error = ELFNAME(read_from)(p, vp, eh.e_phoff,
(caddr_t) ph, phsize)) != 0)
goto bad;
/*
* Load all the necessary sections
*/
for (i = 0; i < eh.e_phnum; i++) {
u_long size = 0;
int prot = 0;
switch (ph[i].p_type) {
case Elf_pt_load:
ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
&size, &prot);
/* If entry is within this section it must be text */
if (eh.e_entry >= ph[i].p_vaddr &&
eh.e_entry < (ph[i].p_vaddr + size)) {
/* XXX */
*entry = addr + eh.e_entry;
#ifdef mips
*entry -= ph[i].p_vaddr;
#endif
ap->arg_interp = addr;
}
addr += size;
break;
case Elf_pt_dynamic:
case Elf_pt_phdr:
case Elf_pt_note:
break;
default:
break;
}
}
free((char *)ph, M_TEMP);
*last = addr;
vrele(vp);
return 0;
badunlock:
VOP_UNLOCK(vp);
bad:
if (ph != NULL)
free((char *)ph, M_TEMP);
#ifdef notyet /* XXX cgd 960926 */
(maybe) VOP_CLOSE it
#endif
vrele(vp);
return error;
}
/*
* exec_elf_makecmds(): Prepare an Elf binary's exec package
*
* First, set of the various offsets/lengths in the exec package.
*
* Then, mark the text image busy (so it can be demand paged) or error
* out if this is not possible. Finally, set up vmcmds for the
* text, data, bss, and stack segments.
*/
int
ELFNAME2(exec,makecmds)(p, epp)
struct proc *p;
struct exec_package *epp;
{
Elf_Ehdr *eh = epp->ep_hdr;
Elf_Phdr *ph, *pp;
Elf_Addr phdr = 0, pos = 0;
int error, i, n, nload;
char interp[MAXPATHLEN];
u_long phsize;
if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
return ENOEXEC;
if (ELFNAME(check_header)(eh, Elf_et_exec))
return ENOEXEC;
/*
* check if vnode is in open for writing, because we want to
* demand-page out of it. if it is, don't do it, for various
* reasons
*/
if (epp->ep_vp->v_writecount != 0) {
#ifdef DIAGNOSTIC
if (epp->ep_vp->v_flag & VTEXT)
panic("exec: a VTEXT vnode has writecount != 0\n");
#endif
return ETXTBSY;
}
/*
* Allocate space to hold all the program headers, and read them
* from the file
*/
phsize = eh->e_phnum * sizeof(Elf_Phdr);
ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
if ((error = ELFNAME(read_from)(p, epp->ep_vp, eh->e_phoff,
(caddr_t) ph, phsize)) != 0)
goto bad;
epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
interp[0] = '\0';
for (i = 0; i < eh->e_phnum; i++) {
pp = &ph[i];
if (pp->p_type == Elf_pt_interp) {
if (pp->p_filesz >= sizeof(interp))
goto bad;
if ((error = ELFNAME(read_from)(p, epp->ep_vp,
pp->p_offset, (caddr_t) interp,
pp->p_filesz)) != 0)
goto bad;
break;
}
}
/*
* Setup things for native emulation.
*/
epp->ep_emul = &ELFNAMEEND(emul_netbsd);
pos = ELFDEFNNAME(NO_ADDR);
/*
* On the same architecture, we may be emulating different systems.
* See which one will accept this executable. This currently only
* applies to Linux and SVR4 on the i386.
*
* Probe functions would normally see if the interpreter (if any)
* exists. Emulation packages may possibly replace the interpreter in
* interp[] with a changed path (/emul/xxx/<path>), and also
* set the ep_emul field in the exec package structure.
*/
n = sizeof ELFNAME(probe_funcs) / sizeof ELFNAME(probe_funcs)[0];
if (n != 0) {
error = ENOEXEC;
for (i = 0; i < n && error; i++)
error = ELFNAME(probe_funcs)[i](p, epp, eh,
interp, &pos);
#ifdef notyet
/*
* We should really use a signature in our native binaries
* and have our own probe function for matching binaries,
* before trying the emulations. For now, if the emulation
* probes failed we default to native.
*/
if (error)
goto bad;
#endif
}
/*
* Load all the necessary sections
*/
for (i = nload = 0; i < eh->e_phnum; i++) {
Elf_Addr addr = ELFDEFNNAME(NO_ADDR);
u_long size = 0;
int prot = 0;
pp = &ph[i];
switch (ph[i].p_type) {
case Elf_pt_load:
/*
* XXX
* Can handle only 2 sections: text and data
*/
if (nload++ == 2)
goto bad;
ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
&ph[i], &addr, &size, &prot);
/*
* Decide whether it's text or data by looking
* at the entry point.
*/
if (eh->e_entry >= addr &&
eh->e_entry < (addr + size)) {
epp->ep_taddr = addr;
epp->ep_tsize = size;
if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
epp->ep_daddr = addr;
epp->ep_dsize = size;
}
} else {
epp->ep_daddr = addr;
epp->ep_dsize = size;
}
break;
case Elf_pt_shlib:
error = ENOEXEC;
goto bad;
case Elf_pt_interp:
/* Already did this one */
case Elf_pt_dynamic:
case Elf_pt_note:
break;
case Elf_pt_phdr:
/* Note address of program headers (in text segment) */
phdr = pp->p_vaddr;
break;
default:
/*
* Not fatal; we don't need to understand everything.
*/
break;
}
}
/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
#ifndef ELF_INTERP_NON_RELOCATABLE
/*
* If no position to load the interpreter was set by a probe
* function, pick the same address that a non-fixed mmap(0, ..)
* would (i.e. something safely out of the way).
*/
if (pos == ELFDEFNNAME(NO_ADDR))
pos = round_page(epp->ep_daddr + MAXDSIZ);
#endif /* !ELF_INTERP_NON_RELOCATABLE */
/*
* 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 = ELFNAME(load_file)(p, epp, interp,
&epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) {
free((char *)ap, M_TEMP);
goto bad;
}
pos += phsize;
ap->arg_phaddr = phdr;
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;
#ifdef ELF_MAP_PAGE_ZERO
/* Dell SVR4 maps page zero, yeuch! */
NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, NBPG, 0, epp->ep_vp, 0,
VM_PROT_READ);
#endif
free((char *)ph, M_TEMP);
epp->ep_vp->v_flag |= VTEXT;
return exec_elf_setup_stack(p, epp);
bad:
free((char *)ph, M_TEMP);
kill_vmcmds(&epp->ep_vmcmds);
return ENOEXEC;
}