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[Qemu-devel] [PATCH v2 15/19] linux-user: Use safe_syscall for kill, tki
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH v2 15/19] linux-user: Use safe_syscall for kill, tkill and tgkill syscalls |
Date: |
Fri, 27 May 2016 15:51:57 +0100 |
Use the safe_syscall wrapper for the kill, tkill and tgkill syscalls.
Without this, if a thread sent a SIGKILL to itself it could kill the
thread before we had a chance to process a signal that arrived just
before the SIGKILL, and that signal would get lost.
We drop all the ifdeffery for tkill and tgkill, because every guest
architecture we support implements them, and they've been in Linux
since 2003 so we can assume the host headers define the __NR_tkill
and __NR_tgkill constants.
Signed-off-by: Peter Maydell <address@hidden>
---
Timothy's patchset used block_signals() for this, but I
think safe_syscall is nicer when it can be used, since
it's lower overhead and less intrusive. Also extended to
cover all the thread-killing syscalls rather than just kill.
---
linux-user/syscall.c | 23 +++++++----------------
1 file changed, 7 insertions(+), 16 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index cb5d519..549f571 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -186,8 +186,6 @@ static type name (type1 arg1,type2 arg2,type3 arg3,type4
arg4,type5 arg5, \
#define __NR_sys_getpriority __NR_getpriority
#define __NR_sys_rt_sigqueueinfo __NR_rt_sigqueueinfo
#define __NR_sys_syslog __NR_syslog
-#define __NR_sys_tgkill __NR_tgkill
-#define __NR_sys_tkill __NR_tkill
#define __NR_sys_futex __NR_futex
#define __NR_sys_inotify_init __NR_inotify_init
#define __NR_sys_inotify_add_watch __NR_inotify_add_watch
@@ -225,12 +223,6 @@ _syscall5(int, _llseek, uint, fd, ulong, hi, ulong, lo,
#endif
_syscall3(int,sys_rt_sigqueueinfo,int,pid,int,sig,siginfo_t *,uinfo)
_syscall3(int,sys_syslog,int,type,char*,bufp,int,len)
-#if defined(TARGET_NR_tgkill) && defined(__NR_tgkill)
-_syscall3(int,sys_tgkill,int,tgid,int,pid,int,sig)
-#endif
-#if defined(TARGET_NR_tkill) && defined(__NR_tkill)
-_syscall2(int,sys_tkill,int,tid,int,sig)
-#endif
#ifdef __NR_exit_group
_syscall1(int,exit_group,int,error_code)
#endif
@@ -704,6 +696,9 @@ safe_syscall6(int, pselect6, int, nfds, fd_set *, readfds,
fd_set *, writefds, \
safe_syscall6(int,futex,int *,uaddr,int,op,int,val, \
const struct timespec *,timeout,int *,uaddr2,int,val3)
safe_syscall2(int, rt_sigsuspend, sigset_t *, newset, size_t, sigsetsize)
+safe_syscall2(int, kill, pid_t, pid, int, sig)
+safe_syscall2(int, tkill, int, tid, int, sig)
+safe_syscall3(int, tgkill, int, tgid, int, pid, int, sig)
static inline int host_to_target_sock_type(int host_type)
{
@@ -6528,7 +6523,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
ret = 0;
break;
case TARGET_NR_kill:
- ret = get_errno(kill(arg1, target_to_host_signal(arg2)));
+ ret = get_errno(safe_kill(arg1, target_to_host_signal(arg2)));
break;
#ifdef TARGET_NR_rename
case TARGET_NR_rename:
@@ -9764,18 +9759,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
arg1,
break;
#endif
-#if defined(TARGET_NR_tkill) && defined(__NR_tkill)
case TARGET_NR_tkill:
- ret = get_errno(sys_tkill((int)arg1, target_to_host_signal(arg2)));
+ ret = get_errno(safe_tkill((int)arg1, target_to_host_signal(arg2)));
break;
-#endif
-#if defined(TARGET_NR_tgkill) && defined(__NR_tgkill)
case TARGET_NR_tgkill:
- ret = get_errno(sys_tgkill((int)arg1, (int)arg2,
+ ret = get_errno(safe_tgkill((int)arg1, (int)arg2,
target_to_host_signal(arg3)));
- break;
-#endif
+ break;
#ifdef TARGET_NR_set_robust_list
case TARGET_NR_set_robust_list:
--
1.9.1
- [Qemu-devel] [PATCH v2 03/19] linux-user: Fix stray tab-indent, (continued)
- [Qemu-devel] [PATCH v2 03/19] linux-user: Fix stray tab-indent, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 09/19] linux-user: Remove redundant gdb_queuesig(), Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 08/19] linux-user: Remove redundant default action check in queue_signal(), Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 10/19] linux-user: Remove real-time signal queuing, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 06/19] linux-user: Use safe_syscall for sigsuspend syscalls, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 05/19] linux-user: Define macro for size of host kernel sigset_t, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 07/19] linux-user: Fix race between multiple signals, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 02/19] linux-user: Move handle_pending_signal() to avoid need for declaration, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 01/19] linux-user: Factor out handle_signal code from process_pending_signals(), Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 04/19] linux-user: Factor out uses of do_sigprocmask() from sigreturn code, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 15/19] linux-user: Use safe_syscall for kill, tkill and tgkill syscalls,
Peter Maydell <=
- [Qemu-devel] [PATCH v2 17/19] linux-user: Use both si_code and si_signo when converting siginfo_t, Peter Maydell, 2016/05/27
- [Qemu-devel] [PATCH v2 19/19] linux-user: Avoid possible misalignment in target_to_host_siginfo(), Peter Maydell, 2016/05/27