/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright (c) 2018, Joyent, Inc.
 * Copyright 2022 Oxide Computer Company
 */

/*
 * amd64 specific setup routine  -  relocate ld.so's symbols, setup its
 * environment, map in loadable sections of the executable.
 *
 * Takes base address ld.so was loaded at, address of ld.so's dynamic
 * structure, address of process environment pointers, address of auxiliary
 * vector and * argv[0] (process name).
 * If errors occur, send process signal - otherwise
 * return executable's entry point to the bootstrap routine.
 */

#include        <signal.h>
#include        <stdlib.h>
#include        <sys/auxv.h>
#include        <sys/types.h>
#include        <sys/stat.h>
#include        <link.h>
#include        <dlfcn.h>
#include        "_rtld.h"
#include        "_audit.h"
#include        "msg.h"

/*
 * Number of bytes to save for register usage.
 */
uint_t _plt_save_size;
void (*_plt_fp_save)(void *);
void (*_plt_fp_restore)(void *);

extern void _elf_rtbndr_fp_save_orig(void *);
extern void _elf_rtbndr_fp_restore_orig(void *);
extern void _elf_rtbndr_fp_fxsave(void *);
extern void _elf_rtbndr_fp_fxrestore(void *);
extern void _elf_rtbndr_fp_xsave(void *);
extern void _elf_rtbndr_fp_xrestore(void *);

/*
 * Based on what the kernel has told us, go through and set up the various
 * pointers that we'll need for elf_rtbndr for the FPU.
 */
static void
_setup_plt_fpu(int kind, size_t len)
{
        /*
         * If we didn't get a length for some reason, fall back to the old
         * implementation.
         */
        if (len == 0)
                kind = -1;

        switch (kind) {
        case AT_386_FPINFO_FXSAVE:
                _plt_fp_save = _elf_rtbndr_fp_fxsave;
                _plt_fp_restore = _elf_rtbndr_fp_fxrestore;
                _plt_save_size = len;
                break;
        /*
         * We can treat processors that don't correctly handle the exception
         * information in xsave the same way we do others. The information
         * that may or may not be properly saved and restored should not be
         * relevant to us because of the ABI.
         */
        case AT_386_FPINFO_XSAVE:
        case AT_386_FPINFO_XSAVE_AMD:
                _plt_fp_save = _elf_rtbndr_fp_xsave;
                _plt_fp_restore = _elf_rtbndr_fp_xrestore;
                _plt_save_size = len;
                break;
        default:
                _plt_fp_save = _elf_rtbndr_fp_save_orig;
                _plt_fp_restore = _elf_rtbndr_fp_restore_orig;
                /*
                 * The ABI says that 8 floating point registers are used for
                 * passing arguments (%xmm0 through %xmm7). Because these
                 * registers on some platforms may shadow the %ymm and %zmm
                 * registers, we end up needing to size this for the maximally
                 * sized register we care about, a 512-bit (64-byte) zmm
                 * register.
                 */
                _plt_save_size = 64 * 8;
                break;
        }
}

/* VARARGS */
unsigned long
_setup(Boot *ebp, Dyn *ld_dyn)
{
        ulong_t         reladdr, relacount, ld_base = 0;
        ulong_t         relaent = 0, pltrelsz = 0;
        ulong_t         strtab, soname, interp_base = 0;
        char            *_rt_name, **_envp, **_argv;
        int             _syspagsz = 0, fd = -1;
        uint_t          _flags = 0;
        uint_t          hwcap[3] = { 0, 0, 0 };
        Dyn             *dyn_ptr;
        Phdr            *phdr = NULL;
        Rt_map          *lmp;
        auxv_t          *auxv, *_auxv;
        uid_t           uid = (uid_t)-1, euid = (uid_t)-1;
        gid_t           gid = (gid_t)-1, egid = (gid_t)-1;
        char            *_platform = NULL, *_execname = NULL, *_emulator = NULL;
        int             auxflags = -1, fpkind = -1;
        size_t          fpsize = 0;

        /*
         * Scan the bootstrap structure to pick up the basics.
         */
        for (; ebp->eb_tag != EB_NULL; ebp++)
                switch (ebp->eb_tag) {
                case EB_LDSO_BASE:
                        ld_base = (unsigned long)ebp->eb_un.eb_val;
                        break;
                case EB_ARGV:
                        _argv = (char **)ebp->eb_un.eb_ptr;
                        break;
                case EB_ENVP:
                        _envp = (char **)ebp->eb_un.eb_ptr;
                        break;
                case EB_AUXV:
                        _auxv = (auxv_t *)ebp->eb_un.eb_ptr;
                        break;
                case EB_PAGESIZE:
                        _syspagsz = (int)ebp->eb_un.eb_val;
                        break;
                }

        /*
         * Search the aux. vector for the information passed by exec.
         */
        for (auxv = _auxv; auxv->a_type != AT_NULL; auxv++) {
                switch (auxv->a_type) {
                case AT_EXECFD:
                        /* this is the old exec that passes a file descriptor */
                        fd = (int)auxv->a_un.a_val;
                        break;
                case AT_FLAGS:
                        /* processor flags (MAU available, etc) */
                        _flags = auxv->a_un.a_val;
                        break;
                case AT_PAGESZ:
                        /* system page size */
                        _syspagsz = (int)auxv->a_un.a_val;
                        break;
                case AT_PHDR:
                        /* address of the segment table */
                        phdr = (Phdr *)auxv->a_un.a_ptr;
                        break;
                case AT_BASE:
                        /* interpreter base address */
                        if (ld_base == 0)
                                ld_base = auxv->a_un.a_val;
                        interp_base = auxv->a_un.a_val;
                        break;
                case AT_SUN_UID:
                        /* effective user id for the executable */
                        euid = (uid_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_RUID:
                        /* real user id for the executable */
                        uid = (uid_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_GID:
                        /* effective group id for the executable */
                        egid = (gid_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_RGID:
                        /* real group id for the executable */
                        gid = (gid_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_PLATFORM:
                        /* platform name */
                        _platform = auxv->a_un.a_ptr;
                        break;
                case AT_SUN_EXECNAME:
                        /* full pathname of execed object */
                        _execname = auxv->a_un.a_ptr;
                        break;
                case AT_SUN_AUXFLAGS:
                        /* auxiliary flags */
                        auxflags = (int)auxv->a_un.a_val;
                        break;
                case AT_SUN_HWCAP:
                        /* hardware capabilities */
                        hwcap[0] = (uint_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_HWCAP2:
                        /* hardware capabilities */
                        hwcap[1] = (uint_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_HWCAP3:
                        /* hardware capabilities */
                        hwcap[2] = (uint_t)auxv->a_un.a_val;
                        break;
                case AT_SUN_EMULATOR:
                        /* name of emulation library, if any */
                        _emulator = auxv->a_un.a_ptr;
                        break;
                case AT_SUN_FPTYPE:
                        fpkind = (int)auxv->a_un.a_val;
                        break;
                case AT_SUN_FPSIZE:
                        fpsize = (size_t)auxv->a_un.a_val;
                        break;
                }
        }

        /*
         * Get needed info from ld.so's dynamic structure.
         */
        /* LINTED */
        dyn_ptr = (Dyn *)((char *)ld_dyn + ld_base);
        for (ld_dyn = dyn_ptr; ld_dyn->d_tag != DT_NULL; ld_dyn++) {
                switch (ld_dyn->d_tag) {
                case DT_RELA:
                        reladdr = ld_dyn->d_un.d_ptr + ld_base;
                        break;
                case DT_RELACOUNT:
                        relacount = ld_dyn->d_un.d_val;
                        break;
                case DT_RELAENT:
                        relaent = ld_dyn->d_un.d_val;
                        break;
                case DT_PLTRELSZ:
                        pltrelsz = ld_dyn->d_un.d_val;
                        break;
                case DT_STRTAB:
                        strtab = ld_dyn->d_un.d_ptr + ld_base;
                        break;
                case DT_SONAME:
                        soname = ld_dyn->d_un.d_val;
                        break;
                }
        }
        _rt_name = (char *)strtab + soname;

        /*
         * If we don't have a RELAENT, just assume the size.
         */
        if (relaent == 0)
                relaent = sizeof (Rela);

        /*
         * As all global symbol references within ld.so.1 are protected
         * (symbolic), only RELATIVE and JMPSLOT relocations should be left
         * to process at runtime.  Process all relocations now.
         */
        relacount += (pltrelsz / relaent);
        for (; relacount; relacount--) {
                ulong_t roffset;

                roffset = ((Rela *)reladdr)->r_offset + ld_base;
                *((ulong_t *)roffset) += ld_base +
                    ((Rela *)reladdr)->r_addend;
                reladdr += relaent;
        }

        /*
         * If an emulation library is being used, use that as the linker's
         * effective executable name. The real executable is not linked by this
         * linker.
         */
        if (_emulator != NULL) {
                _execname = _emulator;
                rtld_flags2 |= RT_FL2_BRANDED;
        }

        /*
         * Initialize the dyn_plt_ent_size field.  It currently contains the
         * size of the dyn_plt_template.  It still needs to be aligned and have
         * space for the 'dyn_data' area added.
         */
        dyn_plt_ent_size = ROUND(dyn_plt_ent_size, M_WORD_ALIGN) +
            sizeof (uintptr_t) + sizeof (uintptr_t) + sizeof (ulong_t) +
            sizeof (ulong_t) + sizeof (Sym);

        /*
         * Initialize the amd64 specific PLT relocation constants based on the
         * FP information that we have.
         */
        _setup_plt_fpu(fpkind, fpsize);

        /*
         * Continue with generic startup processing.
         */
        if ((lmp = setup((char **)_envp, (auxv_t *)_auxv, _flags, _platform,
            _syspagsz, _rt_name, ld_base, interp_base, fd, phdr,
            _execname, _argv, uid, euid, gid, egid, auxflags,
            hwcap)) == NULL) {
                rtldexit(&lml_main, 1);
        }

        return (LM_ENTRY_PT(lmp)());
}