cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

getauxval.c (3200B)

      1/*
      2 * QEMU access to the auxiliary vector
      3 *
      4 * Copyright (C) 2013 Red Hat, Inc
      5 *
      6 * Permission is hereby granted, free of charge, to any person obtaining a copy
      7 * of this software and associated documentation files (the "Software"), to deal
      8 * in the Software without restriction, including without limitation the rights
      9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     10 * copies of the Software, and to permit persons to whom the Software is
     11 * furnished to do so, subject to the following conditions:
     12 *
     13 * The above copyright notice and this permission notice shall be included in
     14 * all copies or substantial portions of the Software.
     15 *
     16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     22 * THE SOFTWARE.
     23 */
     24
     25#include "qemu/osdep.h"
     26
     27#ifdef CONFIG_GETAUXVAL
     28/* Don't inline this in qemu/osdep.h, because pulling in <sys/auxv.h> for
     29   the system declaration of getauxval pulls in the system <elf.h>, which
     30   conflicts with qemu's version.  */
     31
     32#include <sys/auxv.h>
     33
     34unsigned long qemu_getauxval(unsigned long key)
     35{
     36    return getauxval(key);
     37}
     38#elif defined(__linux__)
     39#include "elf.h"
     40
     41/* Our elf.h doesn't contain Elf32_auxv_t and Elf64_auxv_t, which is ok because
     42   that just makes it easier to define it properly for the host here.  */
     43typedef struct {
     44    unsigned long a_type;
     45    unsigned long a_val;
     46} ElfW_auxv_t;
     47
     48static const ElfW_auxv_t *auxv;
     49
     50static const ElfW_auxv_t *qemu_init_auxval(void)
     51{
     52    ElfW_auxv_t *a;
     53    ssize_t size = 512, r, ofs;
     54    int fd;
     55
     56    /* Allocate some initial storage.  Make sure the first entry is set
     57       to end-of-list, so that we've got a valid list in case of error.  */
     58    auxv = a = g_malloc(size);
     59    a[0].a_type = 0;
     60    a[0].a_val = 0;
     61
     62    fd = open("/proc/self/auxv", O_RDONLY);
     63    if (fd < 0) {
     64        return a;
     65    }
     66
     67    /* Read the first SIZE bytes.  Hopefully, this covers everything.  */
     68    r = read(fd, a, size);
     69
     70    if (r == size) {
     71        /* Continue to expand until we do get a partial read.  */
     72        do {
     73            ofs = size;
     74            size *= 2;
     75            auxv = a = g_realloc(a, size);
     76            r = read(fd, (char *)a + ofs, ofs);
     77        } while (r == ofs);
     78    }
     79
     80    close(fd);
     81    return a;
     82}
     83
     84unsigned long qemu_getauxval(unsigned long type)
     85{
     86    const ElfW_auxv_t *a = auxv;
     87
     88    if (unlikely(a == NULL)) {
     89        a = qemu_init_auxval();
     90    }
     91
     92    for (; a->a_type != 0; a++) {
     93        if (a->a_type == type) {
     94            return a->a_val;
     95        }
     96    }
     97
     98    return 0;
     99}
    100
    101#elif defined(__FreeBSD__)
    102#include <sys/auxv.h>
    103
    104unsigned long qemu_getauxval(unsigned long type)
    105{
    106    unsigned long aux = 0;
    107    elf_aux_info(type, &aux, sizeof(aux));
    108    return aux;
    109}
    110
    111#else
    112
    113unsigned long qemu_getauxval(unsigned long type)
    114{
    115    return 0;
    116}
    117
    118#endif