a799f071ba
- qemu-user: add device mapper and loopback ioctls, enabling kpatkx OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=40
59 lines
2.0 KiB
Diff
59 lines
2.0 KiB
Diff
From b71ee7a063f7cffdf8a2cf73fcbc1d461fbbb80e Mon Sep 17 00:00:00 2001
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From: Alexander Graf <agraf@suse.de>
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Date: Thu, 24 Nov 2011 00:39:35 +0100
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Subject: [PATCH] linux-user: fix wait* syscall status returns
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When calling wait4 or waitpid with a status pointer and WNOHANG, the
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syscall can potentially not modify the status pointer input. Now if we
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have guest code like:
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int status = 0;
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waitpid(pid, &status, WNOHANG);
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if (status)
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<breakage>
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then we have to make sure that in case status did not change we actually
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return the guest's initialized status variable instead of our own uninitialized.
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We fail to do so today, as we proxy everything through an uninitialized status
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variable which for me ended up always containing the last error code.
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This patch fixes some test cases when building yast2-core in OBS for ARM.
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Signed-off-by: Alexander Graf <agraf@suse.de>
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---
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v1 -> v2:
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- take Peter's comment into account and just not write status back when
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wait*'s return value is 0
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---
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linux-user/syscall.c | 4 ++--
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1 files changed, 2 insertions(+), 2 deletions(-)
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diff --git a/linux-user/syscall.c b/linux-user/syscall.c
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index 3e6f3bd..5810e2a 100644
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--- a/linux-user/syscall.c
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+++ b/linux-user/syscall.c
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@@ -4835,7 +4835,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
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{
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int status;
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ret = get_errno(waitpid(arg1, &status, arg3));
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- if (!is_error(ret) && arg2
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+ if (!is_error(ret) && arg2 && ret
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&& put_user_s32(host_to_target_waitstatus(status), arg2))
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goto efault;
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}
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@@ -6391,7 +6391,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
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rusage_ptr = NULL;
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ret = get_errno(wait4(arg1, &status, arg3, rusage_ptr));
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if (!is_error(ret)) {
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- if (status_ptr) {
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+ if (status_ptr && ret) {
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status = host_to_target_waitstatus(status);
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if (put_user_s32(status, status_ptr))
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goto efault;
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--
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1.6.0.2
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