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-rw-r--r--qemu/util/getauxval.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/qemu/util/getauxval.c b/qemu/util/getauxval.c
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+++ b/qemu/util/getauxval.c
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+/*
+ * 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-common.h"
+#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