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