grub-0.97/stage2/expand.c

	expand.c revision a5602e1bdcf9570fa24684b54cf57a3f22e05ae1
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
 *  Copyright (c) 2013 Joyent, Inc.  All rights reserved.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <expand.h>
#include <shared.h>

#ifdef  SUPPORT_NETBOOT
#include <grub.h>
#endif

#include <cpu.h>

#define EVF_DEFINED 0x01
#define EVF_VALUESET    0x02

typedef struct variable {
    char v_name[EV_NAMELEN];
    unsigned int v_flags;
    char v_value[220];  /* 256 - EV_NAMELEN - sizeof (fields) */
} variable_t;

static variable_t expvars[32];
static const unsigned int nexpvars = 32;

int
set_variable(const char *name, const char *value)
{
    unsigned int i;
    unsigned int avail = nexpvars;

    if (strlen(name) >= sizeof (expvars[0].v_name))
        return (ERR_WONT_FIT);

    if (value != NULL && strlen(value) >= sizeof (expvars[0].v_value))
        return (ERR_WONT_FIT);

    for (i = 0; i < nexpvars; i++) {
        if (expvars[i].v_flags & EVF_DEFINED) {
            if (grub_strcmp(expvars[i].v_name, name) == 0)
                break;
        } else if (i < avail) {
            avail = i;
        }
    }

    if (i == nexpvars) {
        if (avail == nexpvars)
            return (ERR_WONT_FIT);

        i = avail;
        (void) grub_strcpy(expvars[i].v_name, name);
        expvars[i].v_flags = EVF_DEFINED;
    }

    if (value != NULL) {
        (void) grub_strcpy(expvars[i].v_value, value);
        expvars[i].v_flags |= EVF_VALUESET;
    } else {
        expvars[i].v_flags &= ~EVF_VALUESET;
    }

    return (0);
}

const char *
get_variable(const char *name)
{
    unsigned int i;

    for (i = 0; i < nexpvars; i++) {
        if (!(expvars[i].v_flags & EVF_DEFINED))
            continue;
        if (grub_strcmp(expvars[i].v_name, name) == 0) {
            if (expvars[i].v_flags & EVF_VALUESET)
                return (expvars[i].v_value);
            return ("");
        }
    }

    return (NULL);
}

static int
detect_target_operating_mode(void)
{
    int ret, ah;

    /*
     * This function returns 16 bits.  The upper 8 are the value of %ah
     * after calling int 15/ec00.  The lower 8 bits are zero if the BIOS
     * call left CF clear, nonzero otherwise.
     */
    ret = get_target_operating_mode();
    ah = ret & 0xff;
    ret >>= 8;

    if (ah == 0x86 && ret != 0) {
        grub_printf("[BIOS 'Detect Target Operating Mode' "
            "callback unsupported on this platform]\n");
        return (1);     /* unsupported, ignore */
    }

    if (ah == 0 && ret == 0) {
        grub_printf("[BIOS accepted mixed-mode target setting!]\n");
        return (1);     /* told the bios what we're up to */
    }

    if (ah == 0 && ret != 0) {
        grub_printf("fatal: BIOS reports this machine CANNOT run in "
            "mixed 32/64-bit mode!\n");
        return (0);
    }

    grub_printf("warning: BIOS Detect Target Operating Mode callback "
        "confused.\n         %%ax >> 8 = 0x%x, carry = %d\n", ah, ret);

    return (1);
}

static int
amd64_config_cpu(void)
{
    struct amd64_cpuid_regs __vcr, *vcr = &__vcr;
    uint32_t maxeax;
    uint32_t max_maxeax = 0x100;
    char vendor[13];
    int isamd64 = 0;
    uint32_t stdfeatures = 0, xtdfeatures = 0;
    uint64_t efer;

    /*
     * This check may seem silly, but if the C preprocesor symbol __amd64
     * is #defined during compilation, something that may outwardly seem
     * like a good idea, uts/common/sys/isa_defs.h will #define _LP64,
     * which will cause uts/common/sys/int_types.h to typedef uint64_t as
     * an unsigned long - which is only 4 bytes in size when using a 32-bit
     * compiler.
     *
     * If that happens, all the page table translation routines will fail
     * horribly, so check the size of uint64_t just to insure some degree
     * of sanity in future operations.
     */
    /*LINTED [sizeof result is invarient]*/
    if (sizeof (uint64_t) != 8)
        prom_panic("grub compiled improperly, unable to boot "
            "64-bit AMD64 executables");

    /*
     * If the CPU doesn't support the CPUID instruction, it's definitely
     * not an AMD64.
     */
    if (amd64_cpuid_supported() == 0)
        return (0);

    amd64_cpuid_insn(0, vcr);

    maxeax = vcr->r_eax;
    {
        /*LINTED [vendor string from cpuid data]*/
        uint32_t *iptr = (uint32_t *)vendor;

        *iptr++ = vcr->r_ebx;
        *iptr++ = vcr->r_edx;
        *iptr++ = vcr->r_ecx;

        vendor[12] = '\0';
    }

    if (maxeax > max_maxeax) {
        grub_printf("cpu: warning, maxeax was 0x%x -> 0x%x\n",
            maxeax, max_maxeax);
        maxeax = max_maxeax;
    }

    if (maxeax < 1)
        return (0);     /* no additional functions, not an AMD64 */
    else {
        uint_t family, model, step;

        amd64_cpuid_insn(1, vcr);

        /*
         * All AMD64/IA32e processors technically SHOULD report
         * themselves as being in family 0xf, but for some reason
         * Simics doesn't, and this may change in the future, so
         * don't error out if it's not true.
         */
        if ((family = BITX(vcr->r_eax, 11, 8)) == 0xf)
            family += BITX(vcr->r_eax, 27, 20);

        if ((model = BITX(vcr->r_eax, 7, 4)) == 0xf)
            model += BITX(vcr->r_eax, 19, 16) << 4;
        step = BITX(vcr->r_eax, 3, 0);

        grub_printf("cpu: '%s' family %d model %d step %d\n",
            vendor, family, model, step);
        stdfeatures = vcr->r_edx;
    }

    amd64_cpuid_insn(0x80000000, vcr);

    if (vcr->r_eax & 0x80000000) {
        uint32_t xmaxeax = vcr->r_eax;
        const uint32_t max_xmaxeax = 0x80000100;

        if (xmaxeax > max_xmaxeax) {
            grub_printf("amd64: warning, xmaxeax was "
                "0x%x -> 0x%x\n", xmaxeax, max_xmaxeax);
            xmaxeax = max_xmaxeax;
        }

        if (xmaxeax >= 0x80000001) {
            amd64_cpuid_insn(0x80000001, vcr);
            xtdfeatures = vcr->r_edx;
        }
    }

    if (BITX(xtdfeatures, 29, 29))          /* long mode */
        isamd64++;
    else
        grub_printf("amd64: CPU does NOT support long mode\n");

    if (!BITX(stdfeatures, 0, 0)) {
        grub_printf("amd64: CPU does NOT support FPU\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 4, 4)) {
        grub_printf("amd64: CPU does NOT support TSC\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 5, 5)) {
        grub_printf("amd64: CPU does NOT support MSRs\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 6, 6)) {
        grub_printf("amd64: CPU does NOT support PAE\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 8, 8)) {
        grub_printf("amd64: CPU does NOT support CX8\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 13, 13)) {
        grub_printf("amd64: CPU does NOT support PGE\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 19, 19)) {
        grub_printf("amd64: CPU does NOT support CLFSH\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 23, 23)) {
        grub_printf("amd64: CPU does NOT support MMX\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 24, 24)) {
        grub_printf("amd64: CPU does NOT support FXSR\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 25, 25)) {
        grub_printf("amd64: CPU does NOT support SSE\n");
        isamd64--;
    }

    if (!BITX(stdfeatures, 26, 26)) {
        grub_printf("amd64: CPU does NOT support SSE2\n");
        isamd64--;
    }

    if (isamd64 < 1) {
        grub_printf("amd64: CPU does not support amd64 executables.\n");
        return (0);
    }

    amd64_rdmsr(MSR_AMD_EFER, &efer);
    if (efer & AMD_EFER_SCE)
        grub_printf("amd64: EFER_SCE (syscall/sysret) already "
            "enabled\n");
    if (efer & AMD_EFER_NXE)
        grub_printf("amd64: EFER_NXE (no-exec prot) already enabled\n");
    if (efer & AMD_EFER_LME)
        grub_printf("amd64: EFER_LME (long mode) already enabled\n");

    return (detect_target_operating_mode());
}

static int
isamd64()
{
    static int ret = -1;

    if (ret == -1)
        ret = amd64_config_cpu();

    return (ret);
}

static int
check_min_mem64(void)
{
    if (min_mem64 == 0)
        return (1);

    if ((mbi.mem_upper / 10240) * 11 >= min_mem64)
        return (1);

    return (0);
}

/*
 * Given the nul-terminated input string s, expand all variable references
 * within that string into the buffer pointed to by d, which must be of length
 * not less than len bytes.
 *
 * We also expand the special case tokens "$ISADIR" and "$ZFS-BOOTFS" here.
 *
 * If the string will not fit, returns ERR_WONT_FIT.
 * If a nonexistent variable is referenced, returns ERR_NOVAR.
 * Otherwise, returns 0.  The resulting string is nul-terminated.  On error,
 * the contents of the destination buffer are undefined.
 */
int
expand_string(const char *s, char *d, unsigned int len)
{
    unsigned int i;
    int vlen;
    const char *p;
    char *q;
    const char *start;
    char name[EV_NAMELEN];
    const char *val;

    for (p = s, q = d; *p != '\0' && q < d + len; ) {
        /* Special case: $ISADIR */
        if (grub_strncmp(p, "$ISADIR", 7) == 0) {
            if (isamd64() && check_min_mem64()) {
                if (q + 5 >= d + len)
                    return (ERR_WONT_FIT);
                (void) grub_memcpy(q, "amd64", 5);
                q += 5; /* amd64 */
            }
            p += 7; /* $ISADIR */
            continue;
        }
        /* Special case: $ZFS-BOOTFS */
        if (grub_strncmp(p, "$ZFS-BOOTFS", 11) == 0 &&
            is_zfs_mount != 0) {
            if (current_bootpath[0] == '\0' &&
                current_devid[0] == '\0') {
                return (ERR_NO_BOOTPATH);
            }

            /* zfs-bootfs=%s/%u */
            vlen = (current_bootfs_obj > 0) ? 10 : 0;
            vlen += 11;
            vlen += strlen(current_rootpool);

            /* ,bootpath=\"%s\" */
            if (current_bootpath[0] != '\0')
                vlen += 12 + strlen(current_bootpath);

            /* ,diskdevid=\"%s\" */
            if (current_devid[0] != '\0')
                vlen += 13 + strlen(current_devid);

            if (q + vlen >= d + len)
                return (ERR_WONT_FIT);

            if (current_bootfs_obj > 0) {
                q += grub_sprintf(q, "zfs-bootfs=%s/%u",
                    current_rootpool, current_bootfs_obj);
            } else {
                q += grub_sprintf(q, "zfs-bootfs=%s",
                    current_rootpool);
            }
            if (current_bootpath[0] != '\0') {
                q += grub_sprintf(q, ",bootpath=\"%s\"",
                    current_bootpath);
            }
            if (current_devid[0] != '\0') {
                q += grub_sprintf(q, ",diskdevid=\"%s\"",
                    current_devid);
            }

            p += 11;    /* $ZFS-BOOTFS */
            continue;
        }
        if (*p == '$' && *(p + 1) == '{') {
            start = p + 2;
            for (p = start; *p != '\0' && *p != '}' &&
                p - start < sizeof (name) - 1; p++) {
                name[p - start] = *p;
            }
            /*
             * Unterminated reference.  Copy verbatim.
             */
            if (p - start >= sizeof (name) - 1 || *p != '}') {
                p = start;
                *q++ = '$';
                *q++ = '{';
                continue;
            }

            name[p - start] = '\0';
            val = get_variable(name);
            if (val == NULL)
                return (ERR_NOVAR);

            if ((vlen = grub_strlen(val)) >= q + len - d)
                return (ERR_WONT_FIT);

            (void) grub_memcpy(q, val, vlen);
            q += vlen;
            p++;
        } else {
            *q++ = *p++;
        }
    }

    if (q >= d + len)
        return (ERR_WONT_FIT);

    *q = '\0';

    return (0);
}

void
dump_variables(void)
{
    unsigned int i;

    for (i = 0; i < nexpvars; i++) {
        if (!(expvars[i].v_flags & EVF_DEFINED))
            continue;
        (void) grub_printf("[%u] '%s' => '%s'\n", i, expvars[i].v_name,
            (expvars[i].v_flags & EVF_VALUESET) ?
            expvars[i].v_value : "");
    }
}