/*      $OpenBSD: exec_elf.c,v 1.195 2026/02/09 21:58:27 deraadt 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/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/exec.h>
#include <sys/exec_elf.h>
#include <sys/fcntl.h>
#include <sys/ptrace.h>
#include <sys/signalvar.h>
#include <sys/pledge.h>
#include <sys/syscall.h>

#include <sys/mman.h>

#include <uvm/uvm_extern.h>

#include <machine/reg.h>
#include <machine/exec.h>
#include <machine/elf.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     elf_os_pt_note_name(Elf_Note *, int *);
int     elf_os_pt_note(struct proc *, struct exec_package *, Elf_Ehdr *, int *);
int     elf_read_pintable(struct proc *p, struct vnode *vp, Elf_Phdr *pp,
            u_int **pinp, int is_ldso, size_t len);

/* 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

#define ELF_NOTE_NAME_OPENBSD   0x01

struct elf_note_name {
        char *name;
        int id;
} elf_note_names[] = {
        { "OpenBSD",    ELF_NOTE_NAME_OPENBSD },
};

/*
 * 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, endianness, 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;

        /*
         * Apply immutability as much as possible, but not text/rodata
         * segments of textrel binaries, or RELRO or PT_OPENBSD_MUTABLE
         * sections, or LOADS marked PF_OPENBSD_MUTABLE, or LOADS which
         * violate W^X.
         * Userland (meaning crt0 or ld.so) will repair those regions.
         */
        if ((ph->p_flags & (PF_X | PF_W)) != (PF_X | PF_W) &&
            ((ph->p_flags & PF_OPENBSD_MUTABLE) == 0))
                flags |= VMCMD_IMMUTABLE;
        if ((flags & VMCMD_TEXTREL) && (ph->p_flags & PF_W) == 0)
                flags &= ~VMCMD_IMMUTABLE;

        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, NULL, 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);
}

/*
 * rebase the pin offsets inside a base,len window for the text segment only.
 */
void
elf_adjustpins(vaddr_t *basep, size_t *lenp, u_int *pins, int npins, u_int offset)
{
        int i;

        /* Adjust offsets, base, len */
        for (i = 0; i < npins; i++) {
                if (pins[i] == -1 || pins[i] == 0)
                        continue;
                pins[i] -= offset;
        }
        *basep += offset;
        *lenp -= offset;
}

int
elf_read_pintable(struct proc *p, struct vnode *vp, Elf_Phdr *pp,
    u_int **pinp, int is_ldso, size_t len)
{
        struct pinsyscalls {
                u_int offset;
                u_int sysno;
        } *syscalls = NULL;
        int i, nsyscalls = 0, npins = 0;
        u_int *pins = NULL;

        if (pp->p_filesz > SYS_MAXSYSCALL * 2 * sizeof(*syscalls) ||
            pp->p_filesz % sizeof(*syscalls) != 0)
                goto bad;
        nsyscalls = pp->p_filesz / sizeof(*syscalls);
        syscalls = malloc(pp->p_filesz, M_PINSYSCALL, M_WAITOK);
        if (elf_read_from(p, vp, pp->p_offset, syscalls,
            pp->p_filesz) != 0)
                goto bad;

        /* Validate, and calculate pintable size */
        for (i = 0; i < nsyscalls; i++) {
                if (syscalls[i].sysno <= 0 ||
                    syscalls[i].sysno >= SYS_MAXSYSCALL ||
                    syscalls[i].offset > len) {
                        npins = 0;
                        goto bad;
                }
                npins = MAX(npins, syscalls[i].sysno);
        }
        if (is_ldso)
                npins = MAX(npins, SYS_kbind);  /* XXX see ld.so/loader.c */
        npins++;

        /* Fill pintable: 0 = invalid, -1 = allowed, else offset from base */
        pins = mallocarray(npins, sizeof(u_int), M_PINSYSCALL, M_WAITOK|M_ZERO);
        for (i = 0; i < nsyscalls; i++) {
                if (pins[syscalls[i].sysno])
                        pins[syscalls[i].sysno] = -1;   /* duplicated */
                else
                        pins[syscalls[i].sysno] = syscalls[i].offset;
        }
        if (is_ldso)
                pins[SYS_kbind] = -1;   /* XXX see ld.so/loader.c */
        *pinp = pins;
        pins = NULL;
bad:
        free(syscalls, M_PINSYSCALL, nsyscalls * sizeof(*syscalls));
        free(pins, M_PINSYSCALL, npins * sizeof(u_int));
        return npins;
}

/*
 * 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, *syscall_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;
        vaddr_t text_start = -1, text_end = 0;

        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_align > 1) && !powerof2(ph[i].p_align)) {
                        error = EINVAL;
                        goto bad1;
                }

                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);
                        /* 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)) {
                                /* LOAD containing e_entry may not be writable */
                                if (prot & PROT_WRITE) {
                                        error = ENOEXEC;
                                        goto bad1;
                                }
                                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;
                        }
                        if (prot & PROT_EXEC) {
                                if (addr < text_start)
                                        text_start = addr;
                                if (addr+size >= text_end)
                                        text_end = addr + size;
                        }
                        addr += size;
                        break;

                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, NULL, 0, 0);
                        break;

                case PT_DYNAMIC:
#if defined (__mips__)
                        /* DT_DEBUG is not ready on mips */
                        NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
                            ph[i].p_memsz, ph[i].p_vaddr + pos, NULL, 0, 0);
#endif
                        break;
                case PT_GNU_RELRO:
                case PT_OPENBSD_MUTABLE:
                        NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
                            ph[i].p_memsz, ph[i].p_vaddr + pos, NULL, 0, 0);
                        break;
                case PT_OPENBSD_SYSCALLS:
                        syscall_ph = &ph[i];
                        break;
                default:
                        break;
                }
        }

        if (syscall_ph) {
                struct process *pr = p->p_p;
                vaddr_t base = pos;
                size_t len = text_end;
                u_int *pins;
                int npins;

                npins = elf_read_pintable(p, nd.ni_vp, syscall_ph,
                    &pins, 1, len);
                if (npins) {
                        elf_adjustpins(&base, &len, pins, npins,
                            text_start);
                        pr->ps_pin.pn_start = base;
                        pr->ps_pin.pn_end = base + len;
                        pr->ps_pin.pn_pins = pins;
                        pr->ps_pin.pn_npins = npins;
                }
        } else {
                error = EINVAL; /* no pin table */
                goto bad1;
        }

        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, *syscall_ph = NULL;
        Elf_Addr phdr = 0, exe_base = 0, exe_end = 0;
        int error, i, has_phdr = 0, names = 0, textrel = 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_align > 1) && !powerof2(pp->p_align)) {
                        error = EINVAL;
                        goto bad;
                }

                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;
                }
        }

        /*
         * 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;

        if (eh->e_type == ET_DYN) {
                /* need phdr and load sections for PIE */
                if (!has_phdr || base_ph == NULL || base_ph->p_vaddr != 0) {
                        error = EINVAL;
                        goto bad;
                }
                /* randomize exe_base for PIE */
                exe_base = uvm_map_pie(base_ph->p_align);

                /*
                 * Check if DYNAMIC contains DT_TEXTREL
                 */
                for (i = 0, pp = ph; i < eh->e_phnum; i++, pp++) {
                        Elf_Dyn *dt;
                        int j;

                        switch (pp->p_type) {
                        case PT_DYNAMIC:
                                if (pp->p_filesz > 64*1024)
                                        break;
                                dt = malloc(pp->p_filesz, M_TEMP, M_WAITOK);
                                error = vn_rdwr(UIO_READ, epp->ep_vp,
                                    (caddr_t)dt, pp->p_filesz, pp->p_offset,
                                    UIO_SYSSPACE, IO_UNIT, p->p_ucred, NULL, p);
                                if (error) {
                                        free(dt, M_TEMP, pp->p_filesz);
                                        break;
                                }
                                for (j = 0; j < pp->p_filesz / sizeof(*dt); j++) {
                                        if (dt[j].d_tag == DT_TEXTREL) {
                                                textrel = VMCMD_TEXTREL;
                                                break;
                                        }
                                }
                                free(dt, M_TEMP, pp->p_filesz);
                                break;
                        default:
                                break;
                        }
                }
        }

        /*
         * 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;

                        /* Static binaries may not call pinsyscalls() */
                        if (interp == NULL)
                                p->p_vmspace->vm_map.flags |= VM_MAP_PINSYSCALL_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 | textrel);

                        /*
                         * 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;
                                }
                                if (interp == NULL)
                                        exe_end = epp->ep_taddr +
                                            epp->ep_tsize;      /* end of TEXT */
                        }
                        break;

                case PT_SHLIB:
                        error = ENOEXEC;
                        goto bad;

                case PT_INTERP:
                        /* Already did this one */
                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, NULL, 0, 0);
                        break;

                case PT_DYNAMIC:
#if defined (__mips__)
                        /* DT_DEBUG is not ready on mips */
                        NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
                            ph[i].p_memsz, ph[i].p_vaddr + exe_base, NULL, 0, 0);
#endif
                        break;
                case PT_GNU_RELRO:
                case PT_OPENBSD_MUTABLE:
                        NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
                            ph[i].p_memsz, ph[i].p_vaddr + exe_base, NULL, 0, 0);
                        break;
                case PT_OPENBSD_SYSCALLS:
                        if (interp == NULL)
                                syscall_ph = &ph[i];
                        break;
                default:
                        /*
                         * Not fatal, we don't need to understand everything
                         * :-)
                         */
                        break;
                }
        }

        if (syscall_ph) {
                vaddr_t base = exe_base;
                size_t len = exe_end - exe_base;
                u_int *pins;
                int npins;

                npins = elf_read_pintable(p, epp->ep_vp, syscall_ph,
                    &pins, 0, len);
                if (npins) {
                        elf_adjustpins(&base, &len, pins, npins,
                            epp->ep_taddr - exe_base);
                        epp->ep_pinstart = base;
                        epp->ep_pinend = base + len;
                        epp->ep_pins = pins;
                        epp->ep_npins = npins;
                }
        }

        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_args = 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);
}

#ifdef __HAVE_CPU_HWCAP
unsigned long hwcap;
#endif /* __HAVE_CPU_HWCAP */

#ifdef __HAVE_CPU_HWCAP2
unsigned long hwcap2;
#endif /* __HAVE_CPU_HWCAP2 */

/*
 * 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;

        ap = epp->ep_args;
        if (ap == NULL) {
                return (0);
        }

        interp = epp->ep_interp;

        /* disable kbind in programs that don't use ld.so */
        if (interp == NULL)
                p->p_p->ps_kbind_addr = BOGO_PC;

        if (interp &&
            (error = elf_load_file(p, interp, epp, ap)) != 0) {
                free(ap, M_TEMP, sizeof *ap);
                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++;

#ifdef __HAVE_CPU_HWCAP
                a->au_id = AUX_hwcap;
                a->au_v = hwcap;
                a++;
#endif /* __HAVE_CPU_HWCAP */

#ifdef __HAVE_CPU_HWCAP2
                a->au_id = AUX_hwcap2;
                a->au_v = hwcap2;
                a++;
#endif /* __HAVE_CPU_HWCAP2 */

                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_auxinfo, sizeof ai);
        }
        free(ap, M_TEMP, sizeof *ap);
        if (interp)
                pool_put(&namei_pool, interp);
        return (error);
}

int
elf_os_pt_note_name(Elf_Note *np, int *typep)
{
        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) {
                        *typep = np->type;
                        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_OPENBSD_NOBTCFI) {
                        epp->ep_flags |= EXEC_NOBTCFI;
                        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);
                        int name, type;

                        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;
                        name = elf_os_pt_note_name(np2, &type);
                        if (name == ELF_NOTE_NAME_OPENBSD &&
                            type == NT_OPENBSD_PROF)
                                epp->ep_flags |= EXEC_PROFILE;
                        names |= name;
                }
        }

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 *);

extern vaddr_t sigcode_va;
extern vsize_t sigcode_sz;

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, 0);
        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

                /*
                 * Since the sigcode is mapped execute-only, we can't
                 * read it.  So use the kernel mapping for it instead.
                 */
                if (pent->p_vaddr == p->p_p->ps_sigcode &&
                    pent->p_filesz == sigcode_sz) {
                        error = coredump_write(cookie, UIO_SYSSPACE,
                            (void *)sigcode_va, sigcode_sz, 0);
                } else {
                        error = coredump_write(cookie, UIO_USERSPACE,
                            (void *)(vaddr_t)pent->p_vaddr, pent->p_filesz,
                            (pent->p_flags & PF_ISVNODE));
                }
                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), 0);
        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, 0);
                if (error)
                        return error;
                error = coredump_write(ws->iocookie, UIO_SYSSPACE, &shstrtab,
                    sizeof(shstrtab.shdr) + sizeof(shstrtab.shstrtab), 0);
                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 isvnode, 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;
        if (isvnode)
                phdr.p_flags |= PF_ISVNODE;
        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 elfcore_procinfo cpi;
        Elf_Note nhdr;
        struct process *pr = p->p_p;
        struct proc *q;
        size_t size, notesize;
        int error;

        KASSERT(!P_HASSIBLING(p) || pr->ps_single != NULL);
        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_ppid;
                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(ELF_AUX_WORDS * sizeof(char *));
        if (iocookie && pr->ps_auxinfo) {

                nhdr.namesz = sizeof("OpenBSD");
                nhdr.descsz = ELF_AUX_WORDS * sizeof(char *);
                nhdr.type = NT_OPENBSD_AUXV;

                error = coredump_write(iocookie, UIO_SYSSPACE,
                    &nhdr, sizeof(nhdr), 0);
                if (error)
                        return (error);

                error = coredump_write(iocookie, UIO_SYSSPACE,
                    "OpenBSD", elfround(nhdr.namesz), 0);
                if (error)
                        return (error);

                error = coredump_write(iocookie, UIO_USERSPACE,
                    (caddr_t)pr->ps_auxinfo, nhdr.descsz, 0);
                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;

#ifdef __HAVE_COREDUMP_NOTE_ELF_MD
        /* Add machdep per-thread notes. */
        return coredump_note_elf_md(p, iocookie, name, sizep);
#else
        return 0;
#endif
}

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), 0);
        if (error)
                return error;

        error = coredump_write(cookie, UIO_SYSSPACE, name,
            elfround(nhdr->namesz), 0);
        if (error)
                return error;

        return coredump_write(cookie, UIO_SYSSPACE, data, nhdr->descsz, 0);
}
#endif /* !SMALL_KERNEL */