mirror of https://gitee.com/openkylin/qemu.git
110 lines
3.0 KiB
C
110 lines
3.0 KiB
C
/*
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* QEMU access to the auxiliary vector
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*
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* Copyright (C) 2013 Red Hat, Inc
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h"
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#include "qemu/osdep.h"
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#ifdef CONFIG_GETAUXVAL
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/* Don't inline this in qemu/osdep.h, because pulling in <sys/auxv.h> for
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the system declaration of getauxval pulls in the system <elf.h>, which
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conflicts with qemu's version. */
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#include <sys/auxv.h>
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unsigned long qemu_getauxval(unsigned long key)
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{
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return getauxval(key);
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}
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#elif defined(__linux__)
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#include "elf.h"
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/* Our elf.h doesn't contain Elf32_auxv_t and Elf64_auxv_t, which is ok because
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that just makes it easier to define it properly for the host here. */
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typedef struct {
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unsigned long a_type;
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unsigned long a_val;
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} ElfW_auxv_t;
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static const ElfW_auxv_t *auxv;
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static const ElfW_auxv_t *qemu_init_auxval(void)
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{
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ElfW_auxv_t *a;
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ssize_t size = 512, r, ofs;
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int fd;
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/* Allocate some initial storage. Make sure the first entry is set
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to end-of-list, so that we've got a valid list in case of error. */
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auxv = a = g_malloc(size);
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a[0].a_type = 0;
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a[0].a_val = 0;
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fd = open("/proc/self/auxv", O_RDONLY);
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if (fd < 0) {
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return a;
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}
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/* Read the first SIZE bytes. Hopefully, this covers everything. */
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r = read(fd, a, size);
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if (r == size) {
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/* Continue to expand until we do get a partial read. */
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do {
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ofs = size;
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size *= 2;
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auxv = a = g_realloc(a, size);
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r = read(fd, (char *)a + ofs, ofs);
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} while (r == ofs);
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}
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close(fd);
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return a;
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}
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unsigned long qemu_getauxval(unsigned long type)
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{
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const ElfW_auxv_t *a = auxv;
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if (unlikely(a == NULL)) {
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a = qemu_init_auxval();
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}
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for (; a->a_type != 0; a++) {
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if (a->a_type == type) {
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return a->a_val;
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}
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}
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return 0;
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}
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#else
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unsigned long qemu_getauxval(unsigned long type)
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{
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return 0;
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}
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#endif
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