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[Qemu-devel] [PATCH 23/26] qemu/osdep: Remove the need for qemu_init_aux
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 23/26] qemu/osdep: Remove the need for qemu_init_auxval |
Date: |
Thu, 1 May 2014 08:44:44 -0700 |
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.
Signed-off-by: Richard Henderson <address@hidden>
---
include/qemu/osdep.h | 12 ------------
linux-user/main.c | 1 -
util/getauxval.c | 51 +++++++++++++++++++++++++++++++++++++++------------
vl.c | 1 -
4 files changed, 39 insertions(+), 26 deletions(-)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index ffb2966..483778d 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -237,18 +237,6 @@ unsigned long qemu_getauxval(unsigned long type);
static inline unsigned long qemu_getauxval(unsigned long type) { return 0; }
#endif
-/**
- * qemu_init_auxval:
- * @envp: the third argument to main
- *
- * If supported and required, locate the auxiliary vector at program startup.
- */
-#if defined(CONFIG_GETAUXVAL) || !defined(__linux__)
-static inline void qemu_init_auxval(char **envp) { }
-#else
-void qemu_init_auxval(char **envp);
-#endif
-
void qemu_set_tty_echo(int fd, bool echo);
#endif
diff --git a/linux-user/main.c b/linux-user/main.c
index 947358a..0047eff 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3823,7 +3823,6 @@ int main(int argc, char **argv, char **envp)
module_call_init(MODULE_INIT_QOM);
- qemu_init_auxval(envp);
qemu_cache_utils_init();
if ((envlist = envlist_create()) == NULL) {
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;
}
}
diff --git a/vl.c b/vl.c
index 236f95e..5b19c3f 100644
--- a/vl.c
+++ b/vl.c
@@ -3010,7 +3010,6 @@ int main(int argc, char **argv, char **envp)
init_clocks();
rtc_clock = QEMU_CLOCK_HOST;
- qemu_init_auxval(envp);
qemu_cache_utils_init();
QLIST_INIT (&vm_change_state_head);
--
1.9.0
- [Qemu-devel] [PATCH 16/26] tcg-ppc64: Merge ppc32 brcond2, setcond2, muluh, (continued)
- [Qemu-devel] [PATCH 16/26] tcg-ppc64: Merge ppc32 brcond2, setcond2, muluh, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 17/26] tcg-ppc64: Merge ppc32 qemu_ld/st, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 18/26] tcg-ppc64: Merge ppc32 register usage, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 15/26] tcg-ppc64: Begin merging ppc32 with ppc64, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 19/26] tcg-ppc64: Support mulsh_i32, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 21/26] tcg-ppc: Remove the backend, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 20/26] tcg-ppc64: Merge ppc32 shifts, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 22/26] tcg-ppc: Rename the tcg/ppc64 backend, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 24/26] tcg-ppc: Merge cache-utils into the backend, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 25/26] tcg-ppc64: Use the return address as a base pointer, Richard Henderson, 2014/05/01
- [Qemu-devel] [PATCH 23/26] qemu/osdep: Remove the need for qemu_init_auxval,
Richard Henderson <=
- [Qemu-devel] [PATCH 26/26] tcg-ppc: Streamline USE_DIRECT_JUMP, Richard Henderson, 2014/05/01
- Re: [Qemu-devel] [PATCH 00/26] Merge ppc32/ppc64 tcg backends, Tom Musta, 2014/05/02
- Re: [Qemu-devel] [PATCH 00/26] Merge ppc32/ppc64 tcg backends, Ulrich Weigand, 2014/05/02