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IABSD.fr/src/sys/kern/exec_elf.c

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  • Author : pirofti
    Date : 2020-07-06 13:33:05
    Hash : d82e6535
    Message : Add support for timeconting in userland. This diff exposes parts of clock_gettime(2) and gettimeofday(2) to userland via libc eliberating processes from the need for a context switch everytime they want to count the passage of time. If a timecounter clock can be exposed to userland than it needs to set its tc_user member to a non-zero value. Tested with one or multiple counters per architecture. The timing data is shared through a pointer found in the new ELF auxiliary vector AUX_openbsd_timekeep containing timehands information that is frequently updated by the kernel. Timing differences between the last kernel update and the current time are adjusted in userland by the tc_get_timecount() function inside the MD usertc.c file. This permits a much more responsive environment, quite visible in browsers, office programs and gaming (apparently one is are able to fly in Minecraft now). Tested by robert@, sthen@, naddy@, kmos@, phessler@, and many others! OK from at least kettenis@, cheloha@, naddy@, sthen@

  • sys/kern/exec_elf.c
  • /*	$OpenBSD: exec_elf.c,v 1.155 2020/07/06 13:33:09 pirofti Exp $	*/
    
    /*
     * Copyright (c) 1996 Per Fogelstrom
     * All rights reserved.
     *
     * 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.
     *
     */
    
    /*
     * Copyright (c) 2001 Wasabi Systems, Inc.
     * All rights reserved.
     *
     * Written by Jason R. Thorpe for Wasabi Systems, Inc.
     *
     * 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 for the NetBSD Project by
     *	Wasabi Systems, Inc.
     * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     *    or promote products derived from this software without specific prior
     *    written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
     * 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/pool.h>
    #include <sys/mount.h>
    #include <sys/namei.h>
    #include <sys/vnode.h>
    #include <sys/core.h>
    #include <sys/syslog.h>
    #include <sys/exec.h>
    #include <sys/exec_elf.h>
    #include <sys/fcntl.h>
    #include <sys/ptrace.h>
    #include <sys/syscall.h>
    #include <sys/signalvar.h>
    #include <sys/stat.h>
    #include <sys/pledge.h>
    
    #include <sys/mman.h>
    
    #include <uvm/uvm_extern.h>
    
    #include <machine/reg.h>
    #include <machine/exec.h>
    
    int	elf_load_file(struct proc *, char *, struct exec_package *,
    	    struct elf_args *);
    int	elf_check_header(Elf_Ehdr *);
    int	elf_read_from(struct proc *, struct vnode *, u_long, void *, int);
    void	elf_load_psection(struct exec_vmcmd_set *, struct vnode *,
    	    Elf_Phdr *, Elf_Addr *, Elf_Addr *, int *, int);
    int	coredump_elf(struct proc *, void *);
    void	*elf_copyargs(struct exec_package *, struct ps_strings *, void *,
    	    void *);
    int	exec_elf_fixup(struct proc *, struct exec_package *);
    int	elf_os_pt_note_name(Elf_Note *);
    int	elf_os_pt_note(struct proc *, struct exec_package *, Elf_Ehdr *, int *);
    
    extern char sigcode[], esigcode[], sigcoderet[];
    #ifdef SYSCALL_DEBUG
    extern char *syscallnames[];
    #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))
    
    /*
     * We limit the number of program headers to 32, this should
     * be a reasonable limit for ELF, the most we have seen so far is 12
     */
    #define ELF_MAX_VALID_PHDR 32
    
    /*
     * How many entries are in the AuxInfo array we pass to the process?
     */
    #define ELF_AUX_ENTRIES	9
    
    /*
     * This is the OpenBSD ELF emul
     */
    struct emul emul_elf = {
    	"native",
    	NULL,
    	SYS_syscall,
    	SYS_MAXSYSCALL,
    	sysent,
    #ifdef SYSCALL_DEBUG
    	syscallnames,
    #else
    	NULL,
    #endif
    	(sizeof(AuxInfo) * ELF_AUX_ENTRIES / sizeof(char *)),
    	elf_copyargs,
    	setregs,
    	exec_elf_fixup,
    	coredump_elf,
    	sigcode,
    	esigcode,
    	sigcoderet
    };
    
    #define ELF_NOTE_NAME_OPENBSD	0x01
    #define ELF_NOTE_NAME_GO	0x02
    
    struct elf_note_name {
    	char *name;
    	int id;
    } elf_note_names[] = {
    	{ "OpenBSD",	ELF_NOTE_NAME_OPENBSD },
    	{ "Go",		ELF_NOTE_NAME_GO }
    };
    
    #define	ELFROUNDSIZE	sizeof(Elf_Word)
    #define	elfround(x)	roundup((x), ELFROUNDSIZE)
    
    /*
     * Copy arguments onto the stack in the normal way, but add some
     * space for extra information in case of dynamic binding.
     */
    void *
    elf_copyargs(struct exec_package *pack, struct ps_strings *arginfo,
    		void *stack, void *argp)
    {
    	stack = copyargs(pack, arginfo, stack, argp);
    	if (!stack)
    		return (NULL);
    
    	/*
    	 * Push space for extra arguments on the stack needed by
    	 * dynamically linked binaries.
    	 */
    	if (pack->ep_emul_arg != NULL) {
    		pack->ep_emul_argp = stack;
    		stack = (char *)stack + ELF_AUX_ENTRIES * sizeof (AuxInfo);
    	}
    	return (stack);
    }
    
    /*
     * Check header for validity; return 0 for ok, ENOEXEC if error
     */
    int
    elf_check_header(Elf_Ehdr *ehdr)
    {
    	/*
    	 * We need to check magic, class size, endianess, and version before
    	 * we look at the rest of the Elf_Ehdr structure. These few elements
    	 * are represented in a machine independent fashion.
    	 */
    	if (!IS_ELF(*ehdr) ||
    	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
    	    ehdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
    	    ehdr->e_ident[EI_VERSION] != ELF_TARG_VER)
    		return (ENOEXEC);
    
    	/* Now check the machine dependent header */
    	if (ehdr->e_machine != ELF_TARG_MACH ||
    	    ehdr->e_version != ELF_TARG_VER)
    		return (ENOEXEC);
    
    	/* Don't allow an insane amount of sections. */
    	if (ehdr->e_phnum > ELF_MAX_VALID_PHDR)
    		return (ENOEXEC);
    
    	return (0);
    }
    
    /*
     * Load a psection at the appropriate address
     */
    void
    elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp,
        Elf_Phdr *ph, Elf_Addr *addr, Elf_Addr *size, int *prot, int flags)
    {
    	u_long msize, lsize, psize, rm, rf;
    	long diff, offset, bdiff;
    	Elf_Addr base;
    
    	/*
    	 * If the user specified an address, then we load there.
    	 */
    	if (*addr != ELF_NO_ADDR) {
    		if (ph->p_align > 1) {
    			*addr = ELF_TRUNC(*addr, ph->p_align);
    			diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align);
    			/* page align vaddr */
    			base = *addr + trunc_page(ph->p_vaddr) 
    			    - ELF_TRUNC(ph->p_vaddr, ph->p_align);
    		} else {
    			diff = 0;
    			base = *addr + trunc_page(ph->p_vaddr) - ph->p_vaddr;
    		}
    	} else {
    		*addr = ph->p_vaddr;
    		if (ph->p_align > 1)
    			*addr = ELF_TRUNC(*addr, ph->p_align);
    		base = trunc_page(ph->p_vaddr);
    		diff = ph->p_vaddr - *addr;
    	}
    	bdiff = ph->p_vaddr - trunc_page(ph->p_vaddr);
    
    	/*
    	 * Enforce W^X and map W|X segments without X permission
    	 * initially.  The dynamic linker will make these read-only
    	 * and add back X permission after relocation processing.
    	 * Static executables with W|X segments will probably crash.
    	 */
    	*prot |= (ph->p_flags & PF_R) ? PROT_READ : 0;
    	*prot |= (ph->p_flags & PF_W) ? PROT_WRITE : 0;
    	if ((ph->p_flags & PF_W) == 0)
    		*prot |= (ph->p_flags & PF_X) ? PROT_EXEC : 0;
    
    	msize = ph->p_memsz + diff;
    	offset = ph->p_offset - bdiff;
    	lsize = ph->p_filesz + bdiff;
    	psize = round_page(lsize);
    
    	/*
    	 * 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.
    	 */
    	if (ph->p_flags & PF_W) {
    		psize = trunc_page(lsize);
    		if (psize > 0)
    			NEW_VMCMD2(vcset, vmcmd_map_pagedvn, psize, base, vp,
    			    offset, *prot, flags);
    		if (psize != lsize) {
    			NEW_VMCMD2(vcset, vmcmd_map_readvn, lsize - psize,
    			    base + psize, vp, offset + psize, *prot, flags);
    		}
    	} else {
    		NEW_VMCMD2(vcset, vmcmd_map_pagedvn, psize, base, vp, offset,
    		    *prot, flags);
    	}
    
    	/*
    	 * Check if we need to extend the size of the segment
    	 */
    	rm = round_page(*addr + ph->p_memsz + diff);
    	rf = round_page(*addr + ph->p_filesz + diff);
    
    	if (rm != rf) {
    		NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP, 0,
    		    *prot, flags);
    	}
    	*size = msize;
    }
    
    /*
     * Read from vnode into buffer at offset.
     */
    int
    elf_read_from(struct proc *p, struct vnode *vp, u_long off, void *buf,
        int size)
    {
    	int error;
    	size_t 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);
    }
    
    /*
     * 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(struct proc *p, char *path, struct exec_package *epp,
        struct elf_args *ap)
    {
    	int error, i;
    	struct nameidata nd;
    	Elf_Ehdr eh;
    	Elf_Phdr *ph = NULL;
    	u_long phsize = 0;
    	Elf_Addr addr;
    	struct vnode *vp;
    	Elf_Phdr *base_ph = NULL;
    	struct interp_ld_sec {
    		Elf_Addr vaddr;
    		u_long memsz;
    	} loadmap[ELF_MAX_VALID_PHDR];
    	int nload, idx = 0;
    	Elf_Addr pos;
    	int file_align;
    	int loop;
    	size_t randomizequota = ELF_RANDOMIZE_LIMIT;
    
    	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
    	nd.ni_pledge = PLEDGE_RPATH;
    	nd.ni_unveil = UNVEIL_READ;
    	if ((error = namei(&nd)) != 0) {
    		return (error);
    	}
    	vp = nd.ni_vp;
    	if (vp->v_type != VREG) {
    		error = EACCES;
    		goto bad;
    	}
    	if ((error = VOP_GETATTR(vp, epp->ep_vap, p->p_ucred, p)) != 0)
    		goto bad;
    	if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
    		error = EACCES;
    		goto bad;
    	}
    	if ((error = VOP_ACCESS(vp, VREAD, p->p_ucred, p)) != 0)
    		goto bad1;
    	if ((error = elf_read_from(p, nd.ni_vp, 0, &eh, sizeof(eh))) != 0)
    		goto bad1;
    
    	if (elf_check_header(&eh) || eh.e_type != ET_DYN) {
    		error = ENOEXEC;
    		goto bad1;
    	}
    
    	ph = mallocarray(eh.e_phnum, sizeof(Elf_Phdr), M_TEMP, M_WAITOK);
    	phsize = eh.e_phnum * sizeof(Elf_Phdr);
    
    	if ((error = elf_read_from(p, nd.ni_vp, eh.e_phoff, ph, phsize)) != 0)
    		goto bad1;
    
    	for (i = 0; i < eh.e_phnum; i++) {
    		if (ph[i].p_type == PT_LOAD) {
    			if (ph[i].p_filesz > ph[i].p_memsz ||
    			    ph[i].p_memsz == 0) {
    				error = EINVAL;
    				goto bad1;
    			}
    			loadmap[idx].vaddr = trunc_page(ph[i].p_vaddr);
    			loadmap[idx].memsz = round_page (ph[i].p_vaddr +
    			    ph[i].p_memsz - loadmap[idx].vaddr);
    			file_align = ph[i].p_align;
    			idx++;
    		}
    	}
    	nload = idx;
    
    	/*
    	 * Load the interpreter where a non-fixed mmap(NULL, ...)
    	 * would (i.e. something safely out of the way).
    	 */
    	pos = uvm_map_hint(p->p_vmspace, PROT_EXEC, VM_MIN_ADDRESS,
    	    VM_MAXUSER_ADDRESS);
    	pos = ELF_ROUND(pos, file_align);
    
    	loop = 0;
    	for (i = 0; i < nload;/**/) {
    		vaddr_t	addr;
    		struct	uvm_object *uobj;
    		off_t	uoff;
    		size_t	size;
    
    #ifdef this_needs_fixing
    		if (i == 0) {
    			uobj = &vp->v_uvm.u_obj;
    			/* need to fix uoff */
    		} else {
    #endif
    			uobj = NULL;
    			uoff = 0;
    #ifdef this_needs_fixing
    		}
    #endif
    
    		addr = trunc_page(pos + loadmap[i].vaddr);
    		size =  round_page(addr + loadmap[i].memsz) - addr;
    
    		/* CRAP - map_findspace does not avoid daddr+BRKSIZ */
    		if ((addr + size > (vaddr_t)p->p_vmspace->vm_daddr) &&
    		    (addr < (vaddr_t)p->p_vmspace->vm_daddr + BRKSIZ))
    			addr = round_page((vaddr_t)p->p_vmspace->vm_daddr +
    			    BRKSIZ);
    
    		if (uvm_map_mquery(&p->p_vmspace->vm_map, &addr, size,
    		    (i == 0 ? uoff : UVM_UNKNOWN_OFFSET), 0) != 0) {
    			if (loop == 0) {
    				loop = 1;
    				i = 0;
    				pos = 0;
    				continue;
    			}
    			error = ENOMEM;
    			goto bad1;
    		}
    		if (addr != pos + loadmap[i].vaddr) {
    			/* base changed. */
    			pos = addr - trunc_page(loadmap[i].vaddr);
    			pos = ELF_ROUND(pos,file_align);
    			i = 0;
    			continue;
    		}
    
    		i++;
    	}
    
    	/*
    	 * Load all the necessary sections
    	 */
    	for (i = 0; i < eh.e_phnum; i++) {
    		Elf_Addr size = 0;
    		int prot = 0;
    		int flags;
    
    		switch (ph[i].p_type) {
    		case PT_LOAD:
    			if (base_ph == NULL) {
    				flags = VMCMD_BASE;
    				addr = pos;
    				base_ph = &ph[i];
    			} else {
    				flags = VMCMD_RELATIVE;
    				addr = ph[i].p_vaddr - base_ph->p_vaddr;
    			}
    			elf_load_psection(&epp->ep_vmcmds, nd.ni_vp,
    			    &ph[i], &addr, &size, &prot, flags | VMCMD_SYSCALL);
    			/* 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)) {
     				epp->ep_entry = addr + eh.e_entry -
    				    ELF_TRUNC(ph[i].p_vaddr,ph[i].p_align);
    				if (flags == VMCMD_RELATIVE)
    					epp->ep_entry += pos;
    				ap->arg_interp = pos;
    			}
    			addr += size;
    			break;
    
    		case PT_DYNAMIC:
    		case PT_PHDR:
    		case PT_NOTE:
    			break;
    
    		case PT_OPENBSD_RANDOMIZE:
    			if (ph[i].p_memsz > randomizequota) {
    				error = ENOMEM;
    				goto bad1;
    			}
    			randomizequota -= ph[i].p_memsz;
    			NEW_VMCMD(&epp->ep_vmcmds, vmcmd_randomize,
    			    ph[i].p_memsz, ph[i].p_vaddr + pos, NULLVP, 0, 0);
    			break;
    
    		default:
    			break;
    		}
    	}
    
    	vn_marktext(nd.ni_vp);
    
    bad1:
    	VOP_CLOSE(nd.ni_vp, FREAD, p->p_ucred, p);
    bad:
    	free(ph, M_TEMP, phsize);
    
    	vput(nd.ni_vp);
    	return (error);
    }
    
    /*
     * 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(struct proc *p, struct exec_package *epp)
    {
    	Elf_Ehdr *eh = epp->ep_hdr;
    	Elf_Phdr *ph, *pp, *base_ph = NULL;
    	Elf_Addr phdr = 0, exe_base = 0;
    	int error, i, has_phdr = 0, names = 0;
    	char *interp = NULL;
    	u_long phsize;
    	size_t randomizequota = ELF_RANDOMIZE_LIMIT;
    
    	if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
    		return (ENOEXEC);
    
    	if (elf_check_header(eh) ||
    	   (eh->e_type != ET_EXEC && eh->e_type != ET_DYN))
    		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");
    #endif
    		return (ETXTBSY);
    	}
    	/*
    	 * Allocate space to hold all the program headers, and read them
    	 * from the file
    	 */
    	ph = mallocarray(eh->e_phnum, sizeof(Elf_Phdr), M_TEMP, M_WAITOK);
    	phsize = eh->e_phnum * sizeof(Elf_Phdr);
    
    	if ((error = elf_read_from(p, epp->ep_vp, eh->e_phoff, ph,
    	    phsize)) != 0)
    		goto bad;
    
    	epp->ep_tsize = ELF_NO_ADDR;
    	epp->ep_dsize = ELF_NO_ADDR;
    
    	for (i = 0, pp = ph; i < eh->e_phnum; i++, pp++) {
    		if (pp->p_type == PT_INTERP && !interp) {
    			if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN)
    				goto bad;
    			interp = pool_get(&namei_pool, PR_WAITOK);
    			if ((error = elf_read_from(p, epp->ep_vp,
    			    pp->p_offset, interp, pp->p_filesz)) != 0) {
    				goto bad;
    			}
    			if (interp[pp->p_filesz - 1] != '\0')
    				goto bad;
    		} else if (pp->p_type == PT_LOAD) {
    			if (pp->p_filesz > pp->p_memsz ||
    			    pp->p_memsz == 0) {
    				error = EINVAL;
    				goto bad;
    			}
    			if (base_ph == NULL)
    				base_ph = pp;
    		} else if (pp->p_type == PT_PHDR) {
    			has_phdr = 1;
    		}
    	}
    
    	if (eh->e_type == ET_DYN) {
    		/* need phdr and load sections for PIE */
    		if (!has_phdr || base_ph == NULL) {
    			error = EINVAL;
    			goto bad;
    		}
    		/* randomize exe_base for PIE */
    		exe_base = uvm_map_pie(base_ph->p_align);
    	}
    
    	/*
    	 * OK, we want a slightly different twist of the
    	 * standard emulation package for "real" elf.
    	 */
    	epp->ep_emul = &emul_elf;
    
    	/*
    	 * Verify this is an OpenBSD executable.  If it's marked that way
    	 * via a PT_NOTE then also check for a PT_OPENBSD_WXNEEDED segment.
    	 */
    	if ((error = elf_os_pt_note(p, epp, epp->ep_hdr, &names)) != 0)
    		goto bad;
    	if (eh->e_ident[EI_OSABI] == ELFOSABI_OPENBSD)
    		names |= ELF_NOTE_NAME_OPENBSD;
    
    	/*
    	 * Load all the necessary sections
    	 */
    	for (i = 0, pp = ph; i < eh->e_phnum; i++, pp++) {
    		Elf_Addr addr, size = 0;
    		int prot = 0;
    		int flags = 0;
    
    		switch (pp->p_type) {
    		case PT_LOAD:
    			if (exe_base != 0) {
    				if (pp == base_ph) {
    					flags = VMCMD_BASE;
    					addr = exe_base;
    				} else {
    					flags = VMCMD_RELATIVE;
    					addr = pp->p_vaddr - base_ph->p_vaddr;
    				}
    			} else
    				addr = ELF_NO_ADDR;
    
    			/* Permit system calls in specific main-programs */
    			if (names & ELF_NOTE_NAME_GO) {
    				/* go main-binaries; we await a libc future */
    				flags |= VMCMD_SYSCALL;
    			} else if (interp == NULL) {
    				/* statics. Also block the ld.so syscall-grant */
    				flags |= VMCMD_SYSCALL;
    				p->p_vmspace->vm_map.flags |= VM_MAP_SYSCALL_ONCE;
    			}
    
    			/*
    			 * Calculates size of text and data segments
    			 * by starting at first and going to end of last.
    			 * 'rwx' sections are treated as data.
    			 * this is correct for BSS_PLT, but may not be
    			 * for DATA_PLT, is fine for TEXT_PLT.
    			 */
    			elf_load_psection(&epp->ep_vmcmds, epp->ep_vp,
    			    pp, &addr, &size, &prot, flags);
    
    			/*
    			 * Update exe_base in case alignment was off.
    			 * For PIE, addr is relative to exe_base so
    			 * adjust it (non PIE exe_base is 0 so no change).
    			 */
    			if (flags == VMCMD_BASE)
    				exe_base = addr;
    			else
    				addr += exe_base;
    
    			/*
    			 * Decide whether it's text or data by looking
    			 * at the protection of the section
    			 */
    			if (prot & PROT_WRITE) {
    				/* data section */
    				if (epp->ep_dsize == ELF_NO_ADDR) {
    					epp->ep_daddr = addr;
    					epp->ep_dsize = size;
    				} else {
    					if (addr < epp->ep_daddr) {
    						epp->ep_dsize =
    						    epp->ep_dsize +
    						    epp->ep_daddr -
    						    addr;
    						epp->ep_daddr = addr;
    					} else
    						epp->ep_dsize = addr+size -
    						    epp->ep_daddr;
    				}
    			} else if (prot & PROT_EXEC) {
    				/* text section */
    				if (epp->ep_tsize == ELF_NO_ADDR) {
    					epp->ep_taddr = addr;
    					epp->ep_tsize = size;
    				} else {
    					if (addr < epp->ep_taddr) {
    						epp->ep_tsize =
    						    epp->ep_tsize +
    						    epp->ep_taddr -
    						    addr;
    						epp->ep_taddr = addr;
    					} else
    						epp->ep_tsize = addr+size -
    						    epp->ep_taddr;
    				}
    			}
    			break;
    
    		case PT_SHLIB:
    			error = ENOEXEC;
    			goto bad;
    
    		case PT_INTERP:
    			/* Already did this one */
    		case PT_DYNAMIC:
    		case PT_NOTE:
    			break;
    
    		case PT_PHDR:
    			/* Note address of program headers (in text segment) */
    			phdr = pp->p_vaddr;
    			break;
    
    		case PT_OPENBSD_RANDOMIZE:
    			if (ph[i].p_memsz > randomizequota) {
    				error = ENOMEM;
    				goto bad;
    			}
    			randomizequota -= ph[i].p_memsz;
    			NEW_VMCMD(&epp->ep_vmcmds, vmcmd_randomize,
    			    ph[i].p_memsz, ph[i].p_vaddr + exe_base, NULLVP, 0, 0);
    			break;
    
    		default:
    			/*
    			 * Not fatal, we don't need to understand everything
    			 * :-)
    			 */
    			break;
    		}
    	}
    
    	phdr += exe_base;
    
    	/*
    	 * Strangely some linux programs may have all load sections marked
    	 * writeable, in this case, textsize is not -1, but rather 0;
    	 */
    	if (epp->ep_tsize == ELF_NO_ADDR)
    		epp->ep_tsize = 0;
    	/*
    	 * Another possibility is that it has all load sections marked
    	 * read-only.  Fake a zero-sized data segment right after the
    	 * text segment.
    	 */
    	if (epp->ep_dsize == ELF_NO_ADDR) {
    		epp->ep_daddr = round_page(epp->ep_taddr + epp->ep_tsize);
    		epp->ep_dsize = 0;
    	}
    
    	epp->ep_interp = interp;
    	epp->ep_entry = eh->e_entry + exe_base;
    
    	/*
    	 * Check if we found a dynamically linked binary and arrange to load
    	 * its interpreter when the exec file is released.
    	 */
    	if (interp || eh->e_type == ET_DYN) {
    		struct elf_args *ap;
    
    		ap = malloc(sizeof(*ap), M_TEMP, M_WAITOK);
    
    		ap->arg_phaddr = phdr;
    		ap->arg_phentsize = eh->e_phentsize;
    		ap->arg_phnum = eh->e_phnum;
    		ap->arg_entry = eh->e_entry + exe_base;
    		ap->arg_interp = exe_base;
    
    		epp->ep_emul_arg = ap;
    		epp->ep_emul_argsize = sizeof *ap;
    	}
    
    	free(ph, M_TEMP, phsize);
    	vn_marktext(epp->ep_vp);
    	return (exec_setup_stack(p, epp));
    
    bad:
    	if (interp)
    		pool_put(&namei_pool, interp);
    	free(ph, M_TEMP, phsize);
    	kill_vmcmds(&epp->ep_vmcmds);
    	if (error == 0)
    		return (ENOEXEC);
    	return (error);
    }
    
    /*
     * Phase II of load. It is now safe to load the interpreter. Info collected
     * when loading the program is available for setup of the interpreter.
     */
    int
    exec_elf_fixup(struct proc *p, struct exec_package *epp)
    {
    	char	*interp;
    	int	error = 0;
    	struct	elf_args *ap;
    	AuxInfo ai[ELF_AUX_ENTRIES], *a;
    
    	if (epp->ep_emul_arg == NULL) {
    		return (0);
    	}
    
    	interp = epp->ep_interp;
    	ap = epp->ep_emul_arg;
    
    	if (interp &&
    	    (error = elf_load_file(p, interp, epp, ap)) != 0) {
    		free(ap, M_TEMP, epp->ep_emul_argsize);
    		pool_put(&namei_pool, interp);
    		kill_vmcmds(&epp->ep_vmcmds);
    		return (error);
    	}
    	/*
    	 * We have to do this ourselves...
    	 */
    	error = exec_process_vmcmds(p, epp);
    
    	/*
    	 * Push extra arguments on the stack needed by dynamically
    	 * linked binaries
    	 */
    	if (error == 0) {
    		memset(&ai, 0, sizeof ai);
    		a = ai;
    
    		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 = PAGE_SIZE;
    		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_openbsd_timekeep;
    		a->au_v = p->p_p->ps_timekeep;
    		a++;
    
    		a->au_id = AUX_null;
    		a->au_v = 0;
    		a++;
    
    		error = copyout(ai, epp->ep_emul_argp, sizeof ai);
    	}
    	free(ap, M_TEMP, epp->ep_emul_argsize);
    	if (interp)
    		pool_put(&namei_pool, interp);
    	return (error);
    }
    
    int
    elf_os_pt_note_name(Elf_Note *np)
    {
    	int i, j;
    
    	for (i = 0; i < nitems(elf_note_names); i++) {
    		size_t namlen = strlen(elf_note_names[i].name);
    		if (np->namesz < namlen)
    			continue;
    		/* verify name padding (after the NUL) is NUL */
    		for (j = namlen + 1; j < elfround(np->namesz); j++)
    			if (((char *)(np + 1))[j] != '\0')
    				continue;		
    		/* verify desc padding is NUL */
    		for (j = np->descsz; j < elfround(np->descsz); j++)
    			if (((char *)(np + 1))[j] != '\0')
    				continue;		
    		if (strcmp((char *)(np + 1), elf_note_names[i].name) == 0)
    			return elf_note_names[i].id;
    	}
    	return (0);
    }
    
    int
    elf_os_pt_note(struct proc *p, struct exec_package *epp, Elf_Ehdr *eh, int *namesp)
    {
    	Elf_Phdr *hph, *ph;
    	Elf_Note *np = NULL;
    	size_t phsize, offset, pfilesz = 0, total;
    	int error, names = 0;
    
    	hph = mallocarray(eh->e_phnum, sizeof(Elf_Phdr), M_TEMP, M_WAITOK);
    	phsize = eh->e_phnum * sizeof(Elf_Phdr);
    	if ((error = elf_read_from(p, epp->ep_vp, eh->e_phoff,
    	    hph, phsize)) != 0)
    		goto out1;
    
    	for (ph = hph;  ph < &hph[eh->e_phnum]; ph++) {
    		if (ph->p_type == PT_OPENBSD_WXNEEDED) {
    			epp->ep_flags |= EXEC_WXNEEDED;
    			continue;
    		}
    
    		if (ph->p_type != PT_NOTE || ph->p_filesz > 1024)
    			continue;
    
    		if (np && ph->p_filesz != pfilesz) {
    			free(np, M_TEMP, pfilesz);
    			np = NULL;
    		}
    		if (!np)
    			np = malloc(ph->p_filesz, M_TEMP, M_WAITOK);
    		pfilesz = ph->p_filesz;
    		if ((error = elf_read_from(p, epp->ep_vp, ph->p_offset,
    		    np, ph->p_filesz)) != 0)
    			goto out2;
    
    		for (offset = 0; offset < ph->p_filesz; offset += total) {
    			Elf_Note *np2 = (Elf_Note *)((char *)np + offset);
    
    			if (offset + sizeof(Elf_Note) > ph->p_filesz)
    				break;
    			total = sizeof(Elf_Note) + elfround(np2->namesz) +
    			    elfround(np2->descsz);
    			if (offset + total > ph->p_filesz)
    				break;
    			names |= elf_os_pt_note_name(np2);
    		}
    	}
    
    out2:
    	free(np, M_TEMP, pfilesz);
    out1:
    	free(hph, M_TEMP, phsize);
    	*namesp = names;
    	return ((names & ELF_NOTE_NAME_OPENBSD) ? 0 : ENOEXEC);
    }
    
    /*
     * Start of routines related to dumping core
     */
    
    #ifdef SMALL_KERNEL
    int
    coredump_elf(struct proc *p, void *cookie)
    {
    	return EPERM;
    }
    #else /* !SMALL_KERNEL */
    
    struct writesegs_state {
    	off_t	notestart;
    	off_t	secstart;
    	off_t	secoff;
    	struct	proc *p;
    	void	*iocookie;
    	Elf_Phdr *psections;
    	size_t	psectionslen;
    	size_t	notesize;
    	int	npsections;
    };
    
    uvm_coredump_setup_cb	coredump_setup_elf;
    uvm_coredump_walk_cb	coredump_walk_elf;
    
    int	coredump_notes_elf(struct proc *, void *, size_t *);
    int	coredump_note_elf(struct proc *, void *, size_t *);
    int	coredump_writenote_elf(struct proc *, void *, Elf_Note *,
    	    const char *, void *);
    
    int
    coredump_elf(struct proc *p, void *cookie)
    {
    #ifdef DIAGNOSTIC
    	off_t offset;
    #endif
    	struct writesegs_state ws;
    	size_t notesize;
    	int error, i;
    
    	ws.p = p;
    	ws.iocookie = cookie;
    	ws.psections = NULL;
    
    	/*
    	 * Walk the map to get all the segment offsets and lengths,
    	 * write out the ELF header.
    	 */
    	error = uvm_coredump_walkmap(p, coredump_setup_elf,
    	    coredump_walk_elf, &ws);
    	if (error)
    		goto out;
    
    	error = coredump_write(cookie, UIO_SYSSPACE, ws.psections,
    	    ws.psectionslen);
    	if (error)
    		goto out;
    
    	/* Write out the notes. */
    	error = coredump_notes_elf(p, cookie, &notesize);
    	if (error)
    		goto out;
    
    #ifdef DIAGNOSTIC
    	if (notesize != ws.notesize)
    		panic("coredump: notesize changed: %zu != %zu",
    		    ws.notesize, notesize);
    	offset = ws.notestart + notesize;
    	if (offset != ws.secstart)
    		panic("coredump: offset %lld != secstart %lld",
    		    (long long) offset, (long long) ws.secstart);
    #endif
    
    	/* Pass 3: finally, write the sections themselves. */
    	for (i = 0; i < ws.npsections - 1; i++) {
    		Elf_Phdr *pent = &ws.psections[i];
    		if (pent->p_filesz == 0)
    			continue;
    
    #ifdef DIAGNOSTIC
    		if (offset != pent->p_offset)
    			panic("coredump: offset %lld != p_offset[%d] %lld",
    			    (long long) offset, i,
    			    (long long) pent->p_filesz);
    #endif
    
    		error = coredump_write(cookie, UIO_USERSPACE,
    		    (void *)(vaddr_t)pent->p_vaddr, pent->p_filesz);
    		if (error)
    			goto out;
    
    		coredump_unmap(cookie, (vaddr_t)pent->p_vaddr,
    		    (vaddr_t)pent->p_vaddr + pent->p_filesz);
    
    #ifdef DIAGNOSTIC
    		offset += ws.psections[i].p_filesz;
    #endif
    	}
    
    out:
    	free(ws.psections, M_TEMP, ws.psectionslen);
    	return (error);
    }
    
    
    /*
     * Normally we lay out core files like this:
     *	[ELF Header] [Program headers] [Notes] [data for PT_LOAD segments]
     *
     * However, if there's >= 65535 segments then it overflows the field
     * in the ELF header, so the standard specifies putting a magic
     * number there and saving the real count in the .sh_info field of
     * the first *section* header...which requires generating a section
     * header.  To avoid confusing tools, we include an .shstrtab section
     * as well so all the indexes look valid.  So in this case we lay
     * out the core file like this:
     *	[ELF Header] [Section Headers] [.shstrtab] [Program headers] \
     *	[Notes] [data for PT_LOAD segments]
     *
     * The 'shstrtab' structure below is data for the second of the two
     * section headers, plus the .shstrtab itself, in one const buffer.
     */
    static const struct {
        Elf_Shdr	shdr;
        char	shstrtab[sizeof(ELF_SHSTRTAB) + 1];
    } shstrtab = {
        .shdr = {
    	.sh_name = 1,			/* offset in .shstrtab below */
    	.sh_type = SHT_STRTAB,
    	.sh_offset = sizeof(Elf_Ehdr) + 2*sizeof(Elf_Shdr),
    	.sh_size = sizeof(ELF_SHSTRTAB) + 1,
    	.sh_addralign = 1,
        },
        .shstrtab = "\0" ELF_SHSTRTAB,
    };
    
    int
    coredump_setup_elf(int segment_count, void *cookie)
    {
    	Elf_Ehdr ehdr;
    	struct writesegs_state *ws = cookie;
    	Elf_Phdr *note;
    	int error;
    
    	/* Get the count of segments, plus one for the PT_NOTE */
    	ws->npsections = segment_count + 1;
    
    	/* Get the size of the notes. */
    	error = coredump_notes_elf(ws->p, NULL, &ws->notesize);
    	if (error)
    		return error;
    
    	/* Setup the ELF header */
    	memset(&ehdr, 0, sizeof(ehdr));
    	memcpy(ehdr.e_ident, ELFMAG, SELFMAG);
    	ehdr.e_ident[EI_CLASS] = ELF_TARG_CLASS;
    	ehdr.e_ident[EI_DATA] = ELF_TARG_DATA;
    	ehdr.e_ident[EI_VERSION] = EV_CURRENT;
    	/* XXX Should be the OSABI/ABI version of the executable. */
    	ehdr.e_ident[EI_OSABI] = ELFOSABI_SYSV;
    	ehdr.e_ident[EI_ABIVERSION] = 0;
    	ehdr.e_type = ET_CORE;
    	/* XXX This should be the e_machine of the executable. */
    	ehdr.e_machine = ELF_TARG_MACH;
    	ehdr.e_version = EV_CURRENT;
    	ehdr.e_entry = 0;
    	ehdr.e_flags = 0;
    	ehdr.e_ehsize = sizeof(ehdr);
    	ehdr.e_phentsize = sizeof(Elf_Phdr);
    
    	if (ws->npsections < PN_XNUM) {
    		ehdr.e_phoff = sizeof(ehdr);
    		ehdr.e_shoff = 0;
    		ehdr.e_phnum = ws->npsections;
    		ehdr.e_shentsize = 0;
    		ehdr.e_shnum = 0;
    		ehdr.e_shstrndx = 0;
    	} else {
    		/* too many segments, use extension setup */
    		ehdr.e_shoff = sizeof(ehdr);
    		ehdr.e_phnum = PN_XNUM;
    		ehdr.e_shentsize = sizeof(Elf_Shdr);
    		ehdr.e_shnum = 2;
    		ehdr.e_shstrndx = 1;
    		ehdr.e_phoff = shstrtab.shdr.sh_offset + shstrtab.shdr.sh_size;
    	}
    
    	/* Write out the ELF header. */
    	error = coredump_write(ws->iocookie, UIO_SYSSPACE, &ehdr, sizeof(ehdr));
    	if (error)
    		return error;
    
    	/*
    	 * If an section header is needed to store extension info, write
    	 * it out after the ELF header and before the program header.
    	 */
    	if (ehdr.e_shnum != 0) {
    		Elf_Shdr shdr = { .sh_info = ws->npsections };
    		error = coredump_write(ws->iocookie, UIO_SYSSPACE, &shdr,
    		    sizeof shdr);
    		if (error)
    			return error;
    		error = coredump_write(ws->iocookie, UIO_SYSSPACE, &shstrtab,
    		    sizeof(shstrtab.shdr) + sizeof(shstrtab.shstrtab));
    		if (error)
    			return error;
    	}
    
    	/*
    	 * Allocate the segment header array and setup to collect
    	 * the section sizes and offsets
    	 */
    	ws->psections = mallocarray(ws->npsections, sizeof(Elf_Phdr),
    	    M_TEMP, M_WAITOK|M_CANFAIL|M_ZERO);
    	if (ws->psections == NULL)
    		return ENOMEM;
    	ws->psectionslen = ws->npsections * sizeof(Elf_Phdr);
    
    	ws->notestart = ehdr.e_phoff + ws->psectionslen;
    	ws->secstart = ws->notestart + ws->notesize;
    	ws->secoff = ws->secstart;
    
    	/* Fill in the PT_NOTE segment header in the last slot */
    	note = &ws->psections[ws->npsections - 1];
    	note->p_type = PT_NOTE;
    	note->p_offset = ws->notestart;
    	note->p_vaddr = 0;
    	note->p_paddr = 0;
    	note->p_filesz = ws->notesize;
    	note->p_memsz = 0;
    	note->p_flags = PF_R;
    	note->p_align = ELFROUNDSIZE;
    
    	return (0);
    }
    
    int
    coredump_walk_elf(vaddr_t start, vaddr_t realend, vaddr_t end, vm_prot_t prot,
        int nsegment, void *cookie)
    {
    	struct writesegs_state *ws = cookie;
    	Elf_Phdr phdr;
    	vsize_t size, realsize;
    
    	size = end - start;
    	realsize = realend - start;
    
    	phdr.p_type = PT_LOAD;
    	phdr.p_offset = ws->secoff;
    	phdr.p_vaddr = start;
    	phdr.p_paddr = 0;
    	phdr.p_filesz = realsize;
    	phdr.p_memsz = size;
    	phdr.p_flags = 0;
    	if (prot & PROT_READ)
    		phdr.p_flags |= PF_R;
    	if (prot & PROT_WRITE)
    		phdr.p_flags |= PF_W;
    	if (prot & PROT_EXEC)
    		phdr.p_flags |= PF_X;
    	phdr.p_align = PAGE_SIZE;
    
    	ws->secoff += phdr.p_filesz;
    	ws->psections[nsegment] = phdr;
    
    	return (0);
    }
    
    int
    coredump_notes_elf(struct proc *p, void *iocookie, size_t *sizep)
    {
    	struct ps_strings pss;
    	struct iovec iov;
    	struct uio uio;
    	struct elfcore_procinfo cpi;
    	Elf_Note nhdr;
    	struct process *pr = p->p_p;
    	struct proc *q;
    	size_t size, notesize;
    	int error;
    
    	size = 0;
    
    	/* First, write an elfcore_procinfo. */
    	notesize = sizeof(nhdr) + elfround(sizeof("OpenBSD")) +
    	    elfround(sizeof(cpi));
    	if (iocookie) {
    		memset(&cpi, 0, sizeof(cpi));
    
    		cpi.cpi_version = ELFCORE_PROCINFO_VERSION;
    		cpi.cpi_cpisize = sizeof(cpi);
    		cpi.cpi_signo = p->p_sisig;
    		cpi.cpi_sigcode = p->p_sicode;
    
    		cpi.cpi_sigpend = p->p_siglist | pr->ps_siglist;
    		cpi.cpi_sigmask = p->p_sigmask;
    		cpi.cpi_sigignore = pr->ps_sigacts->ps_sigignore;
    		cpi.cpi_sigcatch = pr->ps_sigacts->ps_sigcatch;
    
    		cpi.cpi_pid = pr->ps_pid;
    		cpi.cpi_ppid = pr->ps_pptr->ps_pid;
    		cpi.cpi_pgrp = pr->ps_pgid;
    		if (pr->ps_session->s_leader)
    			cpi.cpi_sid = pr->ps_session->s_leader->ps_pid;
    		else
    			cpi.cpi_sid = 0;
    
    		cpi.cpi_ruid = p->p_ucred->cr_ruid;
    		cpi.cpi_euid = p->p_ucred->cr_uid;
    		cpi.cpi_svuid = p->p_ucred->cr_svuid;
    
    		cpi.cpi_rgid = p->p_ucred->cr_rgid;
    		cpi.cpi_egid = p->p_ucred->cr_gid;
    		cpi.cpi_svgid = p->p_ucred->cr_svgid;
    
    		(void)strlcpy(cpi.cpi_name, pr->ps_comm, sizeof(cpi.cpi_name));
    
    		nhdr.namesz = sizeof("OpenBSD");
    		nhdr.descsz = sizeof(cpi);
    		nhdr.type = NT_OPENBSD_PROCINFO;
    
    		error = coredump_writenote_elf(p, iocookie, &nhdr,
    		    "OpenBSD", &cpi);
    		if (error)
    			return (error);
    	}
    	size += notesize;
    
    	/* Second, write an NT_OPENBSD_AUXV note. */
    	notesize = sizeof(nhdr) + elfround(sizeof("OpenBSD")) +
    	    elfround(pr->ps_emul->e_arglen * sizeof(char *));
    	if (iocookie) {
    		iov.iov_base = &pss;
    		iov.iov_len = sizeof(pss);
    		uio.uio_iov = &iov;
    		uio.uio_iovcnt = 1;
    		uio.uio_offset = (off_t)pr->ps_strings;
    		uio.uio_resid = sizeof(pss);
    		uio.uio_segflg = UIO_SYSSPACE;
    		uio.uio_rw = UIO_READ;
    		uio.uio_procp = NULL;
    
    		error = uvm_io(&p->p_vmspace->vm_map, &uio, 0);
    		if (error)
    			return (error);
    
    		if (pss.ps_envstr == NULL)
    			return (EIO);
    
    		nhdr.namesz = sizeof("OpenBSD");
    		nhdr.descsz = pr->ps_emul->e_arglen * sizeof(char *);
    		nhdr.type = NT_OPENBSD_AUXV;
    
    		error = coredump_write(iocookie, UIO_SYSSPACE,
    		    &nhdr, sizeof(nhdr));
    		if (error)
    			return (error);
    
    		error = coredump_write(iocookie, UIO_SYSSPACE,
    		    "OpenBSD", elfround(nhdr.namesz));
    		if (error)
    			return (error);
    
    		error = coredump_write(iocookie, UIO_USERSPACE,
    		    pss.ps_envstr + pss.ps_nenvstr + 1, nhdr.descsz);
    		if (error)
    			return (error);
    	}
    	size += notesize;
    
    #ifdef PT_WCOOKIE
    	notesize = sizeof(nhdr) + elfround(sizeof("OpenBSD")) +
    	    elfround(sizeof(register_t));
    	if (iocookie) {
    		register_t wcookie;
    
    		nhdr.namesz = sizeof("OpenBSD");
    		nhdr.descsz = sizeof(register_t);
    		nhdr.type = NT_OPENBSD_WCOOKIE;
    
    		wcookie = process_get_wcookie(p);
    		error = coredump_writenote_elf(p, iocookie, &nhdr,
    		    "OpenBSD", &wcookie);
    		if (error)
    			return (error);
    	}
    	size += notesize;
    #endif
    
    	/*
    	 * Now write the register info for the thread that caused the
    	 * coredump.
    	 */
    	error = coredump_note_elf(p, iocookie, &notesize);
    	if (error)
    		return (error);
    	size += notesize;
    
    	/*
    	 * Now, for each thread, write the register info and any other
    	 * per-thread notes.  Since we're dumping core, all the other
    	 * threads in the process have been stopped and the list can't
    	 * change.
    	 */
    	TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) {
    		if (q == p)		/* we've taken care of this thread */
    			continue;
    		error = coredump_note_elf(q, iocookie, &notesize);
    		if (error)
    			return (error);
    		size += notesize;
    	}
    
    	*sizep = size;
    	return (0);
    }
    
    int
    coredump_note_elf(struct proc *p, void *iocookie, size_t *sizep)
    {
    	Elf_Note nhdr;
    	int size, notesize, error;
    	int namesize;
    	char name[64+ELFROUNDSIZE];
    	struct reg intreg;
    #ifdef PT_GETFPREGS
    	struct fpreg freg;
    #endif
    
    	size = 0;
    
    	snprintf(name, sizeof(name)-ELFROUNDSIZE, "%s@%d",
    	    "OpenBSD", p->p_tid + THREAD_PID_OFFSET);
    	namesize = strlen(name) + 1;
    	memset(name + namesize, 0, elfround(namesize) - namesize);
    
    	notesize = sizeof(nhdr) + elfround(namesize) + elfround(sizeof(intreg));
    	if (iocookie) {
    		error = process_read_regs(p, &intreg);
    		if (error)
    			return (error);
    
    		nhdr.namesz = namesize;
    		nhdr.descsz = sizeof(intreg);
    		nhdr.type = NT_OPENBSD_REGS;
    
    		error = coredump_writenote_elf(p, iocookie, &nhdr,
    		    name, &intreg);
    		if (error)
    			return (error);
    
    	}
    	size += notesize;
    
    #ifdef PT_GETFPREGS
    	notesize = sizeof(nhdr) + elfround(namesize) + elfround(sizeof(freg));
    	if (iocookie) {
    		error = process_read_fpregs(p, &freg);
    		if (error)
    			return (error);
    
    		nhdr.namesz = namesize;
    		nhdr.descsz = sizeof(freg);
    		nhdr.type = NT_OPENBSD_FPREGS;
    
    		error = coredump_writenote_elf(p, iocookie, &nhdr, name, &freg);
    		if (error)
    			return (error);
    	}
    	size += notesize;
    #endif
    
    	*sizep = size;
    	/* XXX Add hook for machdep per-LWP notes. */
    	return (0);
    }
    
    int
    coredump_writenote_elf(struct proc *p, void *cookie, Elf_Note *nhdr,
        const char *name, void *data)
    {
    	int error;
    
    	error = coredump_write(cookie, UIO_SYSSPACE, nhdr, sizeof(*nhdr));
    	if (error)
    		return error;
    
    	error = coredump_write(cookie, UIO_SYSSPACE, name,
    	    elfround(nhdr->namesz));
    	if (error)
    		return error;
    
    	return coredump_write(cookie, UIO_SYSSPACE, data, nhdr->descsz);
    }
    #endif /* !SMALL_KERNEL */