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authorPeter Maydell <peter.maydell@linaro.org>2016-05-27 15:18:40 +0100
committerPeter Maydell <peter.maydell@linaro.org>2016-05-27 15:18:40 +0100
commitfc17f795db96fbc156a647d19f3f7ea506f7ecb9 (patch)
tree00c139800455e8600581ac1b6d923f4e28ef76fa
parentcbc9f5e9e70da7b42b09fc1e92ecc77316f7889a (diff)
downloadqemu-arm-fc17f795db96fbc156a647d19f3f7ea506f7ecb9.tar.gz
linux-user: Use safe_syscall for kill, tkill and tgkill syscalls
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 <peter.maydell@linaro.org> --- 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.
-rw-r--r--linux-user/syscall.c23
1 files changed, 7 insertions, 16 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index cb5d519282..549f571aae 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: