Le 27/05/2016 à 16:51, Peter Maydell a écrit : > 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 <[email protected]>
Reviewed-by: Laurent Vivier <[email protected]> > --- > 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: >
