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authorRichard Henderson <rth@twiddle.net>2014-04-30 13:49:11 -0700
committerRichard Henderson <rth@twiddle.net>2014-06-23 07:32:27 -0700
commit2b45c3f5008bf760e628126f0344c1effbee0714 (patch)
tree03838224e3f7a2ca7995052f5fa557aecf456f3a /util
parent40d964b563d144cae459c39fd6e3a6cd7b34127a (diff)
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qemu/osdep: Remove the need for qemu_init_auxval
Instead of getting backup auxv data from the env pointer given to main, read it from /proc/self/auxv. We can do this at any time, so we're not tied to any ordering wrt a call to qemu_init_auxval from main. Tested-by: Tom Musta <tommusta@gmail.com> Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'util')
-rw-r--r--util/getauxval.c51
1 files changed, 39 insertions, 12 deletions
diff --git a/util/getauxval.c b/util/getauxval.c
index 476c883..25f48e5 100644
--- a/util/getauxval.c
+++ b/util/getauxval.c
@@ -48,24 +48,51 @@ typedef struct {
static const ElfW_auxv_t *auxv;
-void qemu_init_auxval(char **envp)
+static const ElfW_auxv_t *qemu_init_auxval(void)
{
- /* The auxiliary vector is located just beyond the initial environment. */
- while (*envp++ != NULL) {
- continue;
+ 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);
}
- auxv = (const ElfW_auxv_t *)envp;
+
+ close(fd);
+ return a;
}
unsigned long qemu_getauxval(unsigned long type)
{
- /* If we were able to find the auxiliary vector, use it. */
- if (auxv) {
- const ElfW_auxv_t *a;
- for (a = auxv; a->a_type != 0; a++) {
- if (a->a_type == type) {
- return a->a_val;
- }
+ 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;
}
}