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[Qemu-devel] [PATCH 11/19] linux-user: fix wait* syscall status returns
From: |
riku . voipio |
Subject: |
[Qemu-devel] [PATCH 11/19] linux-user: fix wait* syscall status returns |
Date: |
Tue, 31 Jan 2012 11:29:20 +0200 |
From: Alexander Graf <address@hidden>
When calling wait4 or waitpid with a status pointer and WNOHANG, the
syscall can potentially not modify the status pointer input. Now if we
have guest code like:
int status = 0;
waitpid(pid, &status, WNOHANG);
if (status)
<breakage>
then we have to make sure that in case status did not change we actually
return the guest's initialized status variable instead of our own uninitialized.
We fail to do so today, as we proxy everything through an uninitialized status
variable which for me ended up always containing the last error code.
This patch fixes some test cases when building yast2-core in OBS for ARM.
Signed-off-by: Alexander Graf <address@hidden>
Signed-off-by: Riku Voipio <address@hidden>
---
linux-user/syscall.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 29d92c4..06b19e0 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4867,7 +4867,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
{
int status;
ret = get_errno(waitpid(arg1, &status, arg3));
- if (!is_error(ret) && arg2
+ if (!is_error(ret) && arg2 && ret
&& put_user_s32(host_to_target_waitstatus(status), arg2))
goto efault;
}
@@ -6423,7 +6423,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
rusage_ptr = NULL;
ret = get_errno(wait4(arg1, &status, arg3, rusage_ptr));
if (!is_error(ret)) {
- if (status_ptr) {
+ if (status_ptr && ret) {
status = host_to_target_waitstatus(status);
if (put_user_s32(status, status_ptr))
goto efault;
--
1.7.5.4
- [Qemu-devel] [PATCH 00/19] Pending linux-user patches, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 14/19] linux-user: Implement *listxattr syscalls, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 01/19] linux-user: stack_base is now mandatory on all targets, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 07/19] linux-user/main.c: Add option to user-mode emulation so that user can specify log file name, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 04/19] linux-user: fake /proc/self/maps, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 15/19] linux-user: Add default-configs for mipsn32[el], riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 18/19] linux-user: Define TARGET_QEMU_ESIGRETURN for mips64, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 03/19] linux-user: add open() hijack infrastructure, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 10/19] linux-user/strace.c: Correct errno printing for mmap etc, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 11/19] linux-user: fix wait* syscall status returns,
riku . voipio <=
- [Qemu-devel] [PATCH 06/19] linux-user: fake /proc/self/auxv, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 05/19] linux-user: fake /proc/self/stat, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 13/19] linux-user/syscall.c: Implement f and l versions of set/get/removexattr, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 17/19] linux-user: Define TARGET_QEMU_ESIGRETURN for mipsn32, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 12/19] linux-user: Allow NULL value pointer in setxattr and getxattr, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 16/19] linux-user: Add default configs for mips64[el], riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 09/19] linux-user: fix QEMU_STRACE=1 segfault, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 02/19] linux-user: save auxv length, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 19/19] linux-user: Fix sa_flags byte swaps for mips, riku . voipio, 2012/01/31
- [Qemu-devel] [PATCH 08/19] linux-user: add SO_PEERCRED support for getsockopt, riku . voipio, 2012/01/31