linux-user: Use safe_syscall wrapper for poll and ppoll syscalls

Use the safe_syscall wrapper for the poll and ppoll syscalls.
Since not all host architectures will have a poll syscall, we
have to rewrite the TARGET_NR_poll handling to use ppoll instead
(we can assume everywhere has ppoll by now).

We take the opportunity to switch to the code structure
already used in the implementation of epoll_wait and epoll_pwait,
which uses a switch() to avoid interleaving #if and if (),
and to stop using a variable with a leading '_' which is in
the implementation's namespace.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>

linux-user/syscall.c

@@ -429,16 +429,6 @@ static int sys_inotify_init1(int flags)
 #undef TARGET_NR_inotify_rm_watch
 #endif /* CONFIG_INOTIFY  */
 
-#if defined(TARGET_NR_ppoll)
-#ifndef __NR_ppoll
-# define __NR_ppoll -1
-#endif
-#define __NR_sys_ppoll __NR_ppoll
-_syscall5(int, sys_ppoll, struct pollfd *, fds, nfds_t, nfds,
-          struct timespec *, timeout, const sigset_t *, sigmask,
-          size_t, sigsetsize)
-#endif
-
 #if defined(TARGET_NR_prlimit64)
 #ifndef __NR_prlimit64
 # define __NR_prlimit64 -1
@@ -706,6 +696,9 @@ safe_syscall5(int, waitid, idtype_t, idtype, id_t, id, siginfo_t *, infop, \
 safe_syscall3(int, execve, const char *, filename, char **, argv, char **, envp)
 safe_syscall6(int, pselect6, int, nfds, fd_set *, readfds, fd_set *, writefds, \
               fd_set *, exceptfds, struct timespec *, timeout, void *, sig)
+safe_syscall5(int, ppoll, struct pollfd *, ufds, unsigned int, nfds,
+              struct timespec *, tsp, const sigset_t *, sigmask,
+              size_t, sigsetsize)
 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)
@@ -8964,7 +8957,6 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         {
             struct target_pollfd *target_pfd;
             unsigned int nfds = arg2;
-            int timeout = arg3;
             struct pollfd *pfd;
             unsigned int i;
 
@@ -8984,8 +8976,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                 }
             }
 
+            switch (num) {
 # ifdef TARGET_NR_ppoll
-            if (num == TARGET_NR_ppoll) {
+            case TARGET_NR_ppoll:
+            {
                 struct timespec _timeout_ts, *timeout_ts = &_timeout_ts;
                 target_sigset_t *target_set;
                 sigset_t _set, *set = &_set;
@@ -9010,8 +9004,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                     set = NULL;
                 }
 
-                ret = get_errno(sys_ppoll(pfd, nfds, timeout_ts,
-                                          set, SIGSET_T_SIZE));
+                ret = get_errno(safe_ppoll(pfd, nfds, timeout_ts,
+                                           set, SIGSET_T_SIZE));
 
                 if (!is_error(ret) && arg3) {
                     host_to_target_timespec(arg3, timeout_ts);
@@ -9019,9 +9013,30 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                 if (arg4) {
                     unlock_user(target_set, arg4, 0);
                 }
-            } else
+                break;
+            }
+# endif
+# ifdef TARGET_NR_poll
+            case TARGET_NR_poll:
+            {
+                struct timespec ts, *pts;
+
+                if (arg3 >= 0) {
+                    /* Convert ms to secs, ns */
+                    ts.tv_sec = arg3 / 1000;
+                    ts.tv_nsec = (arg3 % 1000) * 1000000LL;
+                    pts = &ts;
+                } else {
+                    /* -ve poll() timeout means "infinite" */
+                    pts = NULL;
+                }
+                ret = get_errno(safe_ppoll(pfd, nfds, pts, NULL, 0));
+                break;
+            }
 # endif
-                ret = get_errno(poll(pfd, nfds, timeout));
+            default:
+                g_assert_not_reached();
+            }
 
             if (!is_error(ret)) {
                 for(i = 0; i < nfds; i++) {