Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20210330' into...
[qemu/ar7.git] / util / getauxval.c
blobb124107d61eadf49bd6182f0633c02802304b9bd
1 /*
2 * QEMU access to the auxiliary vector
4 * Copyright (C) 2013 Red Hat, Inc
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
25 #include "qemu/osdep.h"
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. */
32 #include <sys/auxv.h>
34 unsigned long qemu_getauxval(unsigned long key)
36 return getauxval(key);
38 #elif defined(__linux__)
39 #include "elf.h"
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. */
43 typedef struct {
44 unsigned long a_type;
45 unsigned long a_val;
46 } ElfW_auxv_t;
48 static const ElfW_auxv_t *auxv;
50 static const ElfW_auxv_t *qemu_init_auxval(void)
52 ElfW_auxv_t *a;
53 ssize_t size = 512, r, ofs;
54 int fd;
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;
62 fd = open("/proc/self/auxv", O_RDONLY);
63 if (fd < 0) {
64 return a;
67 /* Read the first SIZE bytes. Hopefully, this covers everything. */
68 r = read(fd, a, size);
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);
80 close(fd);
81 return a;
84 unsigned long qemu_getauxval(unsigned long type)
86 const ElfW_auxv_t *a = auxv;
88 if (unlikely(a == NULL)) {
89 a = qemu_init_auxval();
92 for (; a->a_type != 0; a++) {
93 if (a->a_type == type) {
94 return a->a_val;
98 return 0;
101 #elif defined(__FreeBSD__)
102 #include <sys/auxv.h>
104 unsigned long qemu_getauxval(unsigned long type)
106 unsigned long aux = 0;
107 elf_aux_info(type, &aux, sizeof(aux));
108 return aux;
111 #else
113 unsigned long qemu_getauxval(unsigned long type)
115 return 0;
118 #endif