--- /dev/null
+/* $NetBSD: exec_elf.c,v 1.3 1995/09/16 00:28:08 thorpej Exp $ */
+
+/*
+ * 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.
+ *
+ */
+
+#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/syscall.h>
+#include <sys/signalvar.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>
+#include <machine/exec.h>
+
+#ifdef COMPAT_LINUX
+#include <compat/linux/linux_exec.h>
+#endif
+
+#ifdef COMPAT_SVR4
+#include <compat/svr4/svr4_exec.h>
+#endif
+
+int (*elf_probe_funcs[])() = {
+#ifdef COMPAT_SVR4
+ svr4_elf_probe,
+#endif
+#ifdef COMPAT_LINUX
+ linux_elf_probe
+#endif
+};
+
+static int elf_set_segment __P((struct exec_package *, u_long, u_long,
+ int));
+static int elf_read_from __P((struct proc *, struct vnode *, u_long,
+ caddr_t, int));
+static void elf_load_psection __P((struct exec_vmcmd_set *,
+ struct vnode *, Elf32_Phdr *, u_long *, u_long *, int *));
+
+#define ELF_ALIGN(a, b) ((a) & ~((b) - 1))
+
+/*
+ * This is the basic elf emul.
+ */
+
+extern char sigcode[], esigcode[];
+#ifdef SYSCALL_DEBUG
+extern char *syscallnames[];
+#endif
+
+struct emul emul_elf = {
+ "netbsd",
+ NULL,
+ sendsig,
+ SYS_syscall,
+ SYS_MAXSYSCALL,
+ sysent,
+#ifdef SYSCALL_DEBUG
+ syscallnames,
+#else
+ NULL,
+#endif
+ sizeof(AuxInfo) * 8,
+ elf_copyargs,
+ setregs,
+ sigcode,
+ esigcode,
+};
+
+/*
+ * Copy arguments onto the stack in the normal way, but add some
+ * extra information in case of dynamic binding.
+ */
+void *
+elf_copyargs(pack, arginfo, stack, argp)
+ struct exec_package *pack;
+ struct ps_strings *arginfo;
+ void *stack;
+ void *argp;
+{
+ char **cpp = stack;
+ char *dp, *sp;
+ size_t len;
+ void *nullp = NULL;
+ int argc = arginfo->ps_nargvstr;
+ int envc = arginfo->ps_nenvstr;
+ AuxInfo *a;
+ struct elf_args *ap;
+
+ if (copyout(&argc, cpp++, sizeof(argc)))
+ return NULL;
+
+ dp = (char *) (cpp + argc + envc + 2 + pack->ep_emul->e_arglen);
+ sp = argp;
+
+ /* XXX don't copy them out, remap them! */
+ arginfo->ps_argvstr = cpp; /* remember location of argv for later */
+
+ for (; --argc >= 0; sp += len, dp += len)
+ if (copyout(&dp, cpp++, sizeof(dp)) ||
+ copyoutstr(sp, dp, ARG_MAX, &len))
+ return NULL;
+
+ if (copyout(&nullp, cpp++, sizeof(nullp)))
+ return NULL;
+
+ arginfo->ps_envstr = cpp; /* remember location of envp for later */
+
+ for (; --envc >= 0; sp += len, dp += len)
+ if (copyout(&dp, cpp++, sizeof(dp)) ||
+ copyoutstr(sp, dp, ARG_MAX, &len))
+ return NULL;
+
+ if (copyout(&nullp, cpp++, sizeof(nullp)))
+ return NULL;
+
+ /*
+ * Push extra arguments on the stack needed by dynamically
+ * linked binaries
+ */
+ a = (AuxInfo *) cpp;
+ 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++;
+
+ a->au_id = AUX_null;
+ a->au_v = 0;
+ a++;
+
+ free((char *) ap, M_TEMP);
+ }
+ return a;
+}
+
+/*
+ * elf_check_header():
+ *
+ * Check header for validity; return 0 of ok ENOEXEC if error
+ *
+ * XXX machine type needs to be moved to <machine/param.h> so
+ * just one comparison can be done. Unfortunately, there is both
+ * em_486 and em_386, so this would not work on the i386.
+ */
+int
+elf_check_header(eh, type)
+ Elf32_Ehdr *eh;
+ int type;
+{
+
+ if (bcmp(eh->e_ident, Elf32_e_ident, Elf32_e_siz) != 0)
+ return ENOEXEC;
+
+ switch (eh->e_machine) {
+ /* XXX */
+#ifdef i386
+ case Elf32_em_386:
+ case Elf32_em_486:
+#endif
+#ifdef sparc
+ case Elf32_em_sparc:
+#endif
+#ifdef mips
+ case Elf32_em_mips:
+#endif
+ break;
+
+ default:
+ return ENOEXEC;
+ }
+
+ if (eh->e_type != type)
+ return ENOEXEC;
+
+ return 0;
+}
+
+/*
+ * elf_load_psection():
+ *
+ * Load a psection at the appropriate address
+ */
+static void
+elf_load_psection(vcset, vp, ph, addr, size, prot)
+ struct exec_vmcmd_set *vcset;
+ struct vnode *vp;
+ Elf32_Phdr *ph;
+ u_long *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 != ELF32_NO_ADDR) {
+ if (ph->p_align > 1) {
+ *addr = ELF_ALIGN(*addr + ph->p_align, ph->p_align);
+ uaddr = ELF_ALIGN(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_ALIGN(uaddr, ph->p_align);
+ diff = uaddr - *addr;
+ }
+
+ *prot |= (ph->p_flags & Elf32_pf_r) ? VM_PROT_READ : 0;
+ *prot |= (ph->p_flags & Elf32_pf_w) ? VM_PROT_WRITE : 0;
+ *prot |= (ph->p_flags & Elf32_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 & Elf32_pf_w) {
+ 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_set_segment():
+ *
+ * Decide if the segment is text or data, depending on the protection
+ * and set it appropriately
+ */
+static int
+elf_set_segment(epp, vaddr, size, prot)
+ struct exec_package *epp;
+ u_long vaddr;
+ u_long size;
+ int prot;
+{
+ /*
+ * Kludge: Unfortunately the current implementation of
+ * exec package assumes a single text and data segment.
+ * In Elf we can have more, but here we limit ourselves
+ * to two and hope :-(
+ * We also assume that the text is r-x, and data is rwx or rw-.
+ */
+ switch (prot) {
+ case (VM_PROT_READ | VM_PROT_EXECUTE):
+ if (epp->ep_tsize != ELF32_NO_ADDR)
+ return ENOEXEC;
+ epp->ep_taddr = vaddr;
+ epp->ep_tsize = size;
+ break;
+
+ case (VM_PROT_READ | VM_PROT_WRITE):
+ case (VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE):
+ if (epp->ep_dsize != ELF32_NO_ADDR)
+ return ENOEXEC;
+ epp->ep_daddr = vaddr;
+ epp->ep_dsize = size;
+ break;
+
+ default:
+ return ENOEXEC;
+ }
+ return 0;
+}
+
+/*
+ * elf_read_from():
+ *
+ * Read from vnode into buffer at offset.
+ */
+static int
+elf_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, IO_NODELOCKED, p->p_ucred,
+ &resid, p)) != 0)
+ return error;
+ /*
+ * See if we got all of it
+ */
+ if (resid != 0)
+ return error;
+ 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
+elf_load_file(p, path, vcset, entry, ap, last)
+ struct proc *p;
+ char *path;
+ struct exec_vmcmd_set *vcset;
+ u_long *entry;
+ struct elf_args *ap;
+ u_long *last;
+{
+ int error, i;
+ struct nameidata nd;
+ Elf32_Ehdr eh;
+ Elf32_Phdr *ph = NULL;
+ u_long phsize;
+ char *bp = NULL;
+ u_long 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, UIO_SYSSPACE, path, p);
+ if ((error = namei(&nd)) != 0) {
+ return error;
+ }
+ if ((error = elf_read_from(p, nd.ni_vp, 0, (caddr_t) &eh,
+ sizeof(eh))) != 0)
+ goto bad;
+
+ if ((error = elf_check_header(&eh, Elf32_et_dyn)) != 0)
+ goto bad;
+
+ phsize = eh.e_phnum * sizeof(Elf32_Phdr);
+ ph = (Elf32_Phdr *) malloc(phsize, M_TEMP, M_WAITOK);
+
+ if ((error = elf_read_from(p, nd.ni_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 Elf32_pt_load:
+ elf_load_psection(vcset, nd.ni_vp, &ph[i], &addr,
+ &size, &prot);
+ /* Assume that the text segment is r-x only */
+ if ((prot & PROT_WRITE) == 0) {
+ *entry = addr + eh.e_entry - ph[i].p_vaddr;
+ ap->arg_interp = addr;
+ }
+ addr += size;
+ break;
+
+ case Elf32_pt_dynamic:
+ case Elf32_pt_phdr:
+ case Elf32_pt_note:
+ break;
+
+ default:
+ break;
+ }
+ }
+
+bad:
+ if (ph != NULL)
+ free((char *) ph, M_TEMP);
+
+ *last = addr;
+ vrele(nd.ni_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
+exec_elf_makecmds(p, epp)
+ struct proc *p;
+ struct exec_package *epp;
+{
+ Elf32_Ehdr *eh = epp->ep_hdr;
+ Elf32_Phdr *ph, *pp;
+ int error, i, n;
+ char interp[MAXPATHLEN];
+ u_long pos = 0, phsize;
+
+ if (epp->ep_hdrvalid < sizeof(Elf32_Ehdr))
+ return ENOEXEC;
+
+ if (elf_check_header(eh, Elf32_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(Elf32_Phdr);
+ ph = (Elf32_Phdr *) malloc(phsize, M_TEMP, M_WAITOK);
+
+ if ((error = elf_read_from(p, epp->ep_vp, eh->e_phoff,
+ (caddr_t) ph, phsize)) != 0)
+ goto bad;
+
+ epp->ep_tsize = ELF32_NO_ADDR;
+ epp->ep_dsize = ELF32_NO_ADDR;
+
+ interp[0] = '\0';
+
+ for (i = 0; i < eh->e_phnum; i++) {
+ pp = &ph[i];
+ if (pp->p_type == Elf32_pt_interp) {
+ if (pp->p_filesz >= sizeof(interp))
+ goto bad;
+ if ((error = elf_read_from(p, epp->ep_vp, pp->p_offset,
+ (caddr_t) interp, pp->p_filesz)) != 0)
+ goto bad;
+ break;
+ }
+ }
+
+ /*
+ * OK, we want a slightly different twist of the
+ * standard emulation package for "real" elf.
+ */
+ epp->ep_emul = &emul_elf;
+ pos = ELF32_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.
+ */
+ if ((n = sizeof elf_probe_funcs / sizeof elf_probe_funcs[0])) {
+ error = ENOEXEC;
+ for (i = 0; i < n && error; i++)
+ error = elf_probe_funcs[i](p, epp, interp, &pos);
+
+ if (error)
+ goto bad;
+ }
+
+ /*
+ * Load all the necessary sections
+ */
+ for (i = 0; i < eh->e_phnum; i++) {
+ u_long addr = ELF32_NO_ADDR, size = 0;
+ int prot = 0;
+
+ pp = &ph[i];
+
+ switch (ph[i].p_type) {
+ case Elf32_pt_load:
+ elf_load_psection(&epp->ep_vmcmds, epp->ep_vp,
+ &ph[i], &addr, &size, &prot);
+ if ((error = elf_set_segment(epp, addr, size,
+ prot)) != 0)
+ goto bad;
+ break;
+
+ case Elf32_pt_shlib:
+ error = ENOEXEC;
+ goto bad;
+
+ case Elf32_pt_interp:
+ /* Already did this one */
+ 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;
+}
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