[PATCH 0/2] linux-user: Adding support for a group of 4 time64 syscalls

[PATCH 0/2] linux-user: Adding support for a group of 4 time64 syscalls

[Filip Bozuta]

This two patch series introduces functionality for following
Year 2038 safe syscalls:

--Introduced in first patch--
*ppoll_time64()
*pselect6_time64()

--Introduced in second patch--
*utimensat_time64()
*semtimedop_time64()

Testing notes:

   The implementations of these time64 syscalls was tested
   using tests from the LTP test suite which was built inside
   a chroot.

Filip Bozuta (2):
  linux-user: Add support for ppoll_time64() and pselect6_time64()
  linux-user: Add support for utimensat_time64() and semtimedop_time64()

 linux-user/syscall.c | 154 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 131 insertions(+), 23 deletions(-)

-- 
2.25.1

[PATCH 1/2] linux-user: Add support for 'ppoll_time64()' and 'pselect6_time64()'

[Filip Bozuta]

This patch introduces functionality for following time64 syscalls:

*ppoll_time64

    This is a year 2038 safe variant of:

    int poll(struct pollfd *fds, nfds_t nfds, int timeout)
    -- wait for some event on a file descriptor --
    man page: https://man7.org/linux/man-pages/man2/ppoll.2.html

*pselect6_time64

    This is a year 2038 safe variant of:

    int pselect6(int nfds, fd_set *readfds, fd_set *writefds,
                 fd_set *exceptfds, const struct timespec *timeout,
                 const sigset_t *sigmask);
    -- synchronous I/O multiplexing --
    man page: https://man7.org/linux/man-pages/man2/pselect6.2.html

Implementation notes:

    Year 2038 safe syscalls in this patch were implemented
    with the same code as their regular variants (ppoll() and pselect()).
    A switch/case statement was used to call an apropriate converting
    function for 'struct timespec' between target and host.
    (target_to_host/host_to_target_timespec() for regular and
     target_to_host/host_to_target_timespec64() for time64 variants)

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
---
 linux-user/syscall.c | 101 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 15 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 1211e759c2..8f63a46f58 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -397,7 +397,7 @@ static int sys_getcwd1(char *buf, size_t size)
   return strlen(buf)+1;
 }
 
-#ifdef TARGET_NR_utimensat
+#if defined(TARGET_NR_utimensat)
 #if defined(__NR_utimensat)
 #define __NR_sys_utimensat __NR_utimensat
 _syscall4(int,sys_utimensat,int,dirfd,const char *,pathname,
@@ -763,11 +763,11 @@ safe_syscall5(int, waitid, idtype_t, idtype, id_t, id, siginfo_t *, infop, \
               int, options, struct rusage *, rusage)
 safe_syscall3(int, execve, const char *, filename, char **, argv, char **, envp)
 #if defined(TARGET_NR_select) || defined(TARGET_NR__newselect) || \
-    defined(TARGET_NR_pselect6)
+    defined(TARGET_NR_pselect6) || defined(TARGET_NR_pselect6_time64)
 safe_syscall6(int, pselect6, int, nfds, fd_set *, readfds, fd_set *, writefds, \
               fd_set *, exceptfds, struct timespec *, timeout, void *, sig)
 #endif
-#if defined(TARGET_NR_ppoll) || defined(TARGET_NR_poll)
+#if defined(TARGET_NR_ppoll) || defined(TARGET_NR_ppoll_time64)
 safe_syscall5(int, ppoll, struct pollfd *, ufds, unsigned int, nfds,
               struct timespec *, tsp, const sigset_t *, sigmask,
               size_t, sigsetsize)
@@ -984,7 +984,7 @@ abi_long do_brk(abi_ulong new_brk)
 }
 
 #if defined(TARGET_NR_select) || defined(TARGET_NR__newselect) || \
-    defined(TARGET_NR_pselect6)
+    defined(TARGET_NR_pselect6) || defined(TARGET_NR_pselect6_time64)
 static inline abi_long copy_from_user_fdset(fd_set *fds,
                                             abi_ulong target_fds_addr,
                                             int n)
@@ -1252,7 +1252,8 @@ static inline abi_long target_to_host_timespec(struct timespec *host_ts,
 }
 #endif
 
-#if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64)
+#if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64) || \
+    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64)
 static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
                                                  abi_ulong target_addr)
 {
@@ -9043,8 +9044,13 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 #endif
         return ret;
 #endif
+#if defined(TARGET_NR_pselect6) || defined(TARGET_NR_pselect6_time64)
 #ifdef TARGET_NR_pselect6
     case TARGET_NR_pselect6:
+#endif
+#ifdef TARGET_NR_pselect6_time64
+    case TARGET_NR_pselect6_time64:
+#endif
         {
             abi_long rfd_addr, wfd_addr, efd_addr, n, ts_addr;
             fd_set rfds, wfds, efds;
@@ -9088,8 +9094,21 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
              * use the do_select() helper ...
              */
             if (ts_addr) {
-                if (target_to_host_timespec(&ts, ts_addr)) {
-                    return -TARGET_EFAULT;
+                switch (num) {
+#ifdef TARGET_NR_pselect6
+                case TARGET_NR_pselect6:
+                    if (target_to_host_timespec(&ts, ts_addr)) {
+                        return -TARGET_EFAULT;
+                    }
+                    break;
+#endif
+#ifdef TARGET_NR_pselect6_time64
+                case TARGET_NR_pselect6_time64:
+                    if (target_to_host_timespec64(&ts, ts_addr)) {
+                        return -TARGET_EFAULT;
+                    }
+                    break;
+#endif
                 }
                 ts_ptr = &ts;
             } else {
@@ -9140,8 +9159,22 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                 if (efd_addr && copy_to_user_fdset(efd_addr, &efds, n))
                     return -TARGET_EFAULT;
 
-                if (ts_addr && host_to_target_timespec(ts_addr, &ts))
-                    return -TARGET_EFAULT;
+                switch (num) {
+#ifdef TARGET_NR_pselect6
+                case TARGET_NR_pselect6:
+                    if (ts_addr && host_to_target_timespec(ts_addr, &ts)) {
+                        return -TARGET_EFAULT;
+                    }
+                break;
+#endif
+#ifdef TARGET_NR_pselect6_time64
+                case TARGET_NR_pselect6_time64:
+                    if (ts_addr && host_to_target_timespec64(ts_addr, &ts)) {
+                        return -TARGET_EFAULT;
+                    }
+                break;
+#endif
+                }
             }
         }
         return ret;
@@ -10076,12 +10109,16 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
     case TARGET_NR__newselect:
         return do_select(arg1, arg2, arg3, arg4, arg5);
 #endif
-#if defined(TARGET_NR_poll) || defined(TARGET_NR_ppoll)
+#if defined(TARGET_NR_poll) || defined(TARGET_NR_ppoll) || \
+    defined(TARGET_NR_ppoll_time64)
 # ifdef TARGET_NR_poll
     case TARGET_NR_poll:
 # endif
 # ifdef TARGET_NR_ppoll
     case TARGET_NR_ppoll:
+# endif
+# ifdef TARGET_NR_ppoll_time64
+    case TARGET_NR_ppoll_time64:
 # endif
         {
             struct target_pollfd *target_pfd;
@@ -10110,17 +10147,38 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
             }
 
             switch (num) {
-# ifdef TARGET_NR_ppoll
+#if defined(TARGET_NR_ppoll) || defined(TARGET_NR_ppoll_time64)
+#ifdef TARGET_NR_ppoll
             case TARGET_NR_ppoll:
+#endif
+#ifdef TARGET_NR_ppoll_time64
+            case TARGET_NR_ppoll_time64:
+#endif
             {
                 struct timespec _timeout_ts, *timeout_ts = &_timeout_ts;
                 target_sigset_t *target_set;
                 sigset_t _set, *set = &_set;
 
                 if (arg3) {
-                    if (target_to_host_timespec(timeout_ts, arg3)) {
-                        unlock_user(target_pfd, arg1, 0);
-                        return -TARGET_EFAULT;
+                    switch (num) {
+#ifdef TARGET_NR_ppoll
+                    case TARGET_NR_ppoll:
+                        if (target_to_host_timespec(timeout_ts, arg3)) {
+                            unlock_user(target_pfd, arg1, 0);
+                            return -TARGET_EFAULT;
+                        }
+                    break;
+#endif
+#ifdef TARGET_NR_ppoll_time64
+                    case TARGET_NR_ppoll_time64:
+                        if (target_to_host_timespec64(timeout_ts, arg3)) {
+                            unlock_user(target_pfd, arg1, 0);
+                            return -TARGET_EFAULT;
+                        }
+                    break;
+#endif
+                    default:
+                        g_assert_not_reached();
                     }
                 } else {
                     timeout_ts = NULL;
@@ -10146,7 +10204,20 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
                                            set, SIGSET_T_SIZE));
 
                 if (!is_error(ret) && arg3) {
-                    host_to_target_timespec(arg3, timeout_ts);
+                    switch (num) {
+#ifdef TARGET_NR_ppoll
+                    case TARGET_NR_ppoll:
+                        host_to_target_timespec(arg3, timeout_ts);
+                        break;
+#endif
+#ifdef TARGET_NR_ppoll_time64
+                    case TARGET_NR_ppoll_time64:
+                        host_to_target_timespec64(arg3, timeout_ts);
+                        break;
+#endif
+                    default:
+                        g_assert_not_reached();
+                    }
                 }
                 if (arg4) {
                     unlock_user(target_set, arg4, 0);
-- 
2.25.1

Re: [PATCH 1/2] linux-user: Add support for 'ppoll_time64()' and 'pselect6_time64()'

[Laurent Vivier]

Le 12/08/2020 à 15:57, Filip Bozuta a écrit :
> This patch introduces functionality for following time64 syscalls:
> 
> *ppoll_time64
> 
>     This is a year 2038 safe variant of:
> 
>     int poll(struct pollfd *fds, nfds_t nfds, int timeout)
>     -- wait for some event on a file descriptor --
>     man page: https://man7.org/linux/man-pages/man2/ppoll.2.html
> 
> *pselect6_time64
> 
>     This is a year 2038 safe variant of:
> 
>     int pselect6(int nfds, fd_set *readfds, fd_set *writefds,
>                  fd_set *exceptfds, const struct timespec *timeout,
>                  const sigset_t *sigmask);
>     -- synchronous I/O multiplexing --
>     man page: https://man7.org/linux/man-pages/man2/pselect6.2.html
> 
> Implementation notes:
> 
>     Year 2038 safe syscalls in this patch were implemented
>     with the same code as their regular variants (ppoll() and pselect()).
>     A switch/case statement was used to call an apropriate converting
>     function for 'struct timespec' between target and host.
>     (target_to_host/host_to_target_timespec() for regular and
>      target_to_host/host_to_target_timespec64() for time64 variants)
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/syscall.c | 101 ++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 86 insertions(+), 15 deletions(-)
> 

I think it would be cleaner if you move the code to new functions,
do_ppoll() and do_pselect6() first, and then you introduce a new
parameter "bool time64" to implement the time64 variant (rather than a
switch()) as you do in PATCH 2.

Thanks,
Laurent

[PATCH 2/2] linux-user: Add support for 'utimensat_time64()' and 'semtimedop_time64()'

[Filip Bozuta]

This patch introduces functionality for following time64 syscalls:

*utimensat_time64()

    int utimensat(int dirfd, const char *pathname,
                  const struct timespec times[2], int flags);
    -- change file timestamps with nanosecond precision --
    man page: https://man7.org/linux/man-pages/man2/utimensat.2.html

*semtimedop_time64()

    int semtimedop(int semid, struct sembuf *sops, size_t nsops,
                   const struct timespec *timeout);
    -- System V semaphore operations --
    man page: https://www.man7.org/linux/man-pages/man2/semtimedop.2.html

Implementation notes:

   Syscall 'utimensat_time64()' is implemented in similar way as its
   regular variants only difference being that time64 converting function
   is used to convert values of 'struct timespec' between host and target
   ('target_to_host_timespec64()').

   For syscall 'semtimedop_time64()' and additional argument is added
   in function 'do_semtimedop()' through which the aproppriate 'struct timespec'
   converting function is called (0 for regular target_to_host_timespec()
   and anything else for target_to_host_timespec64()). For 'do_ipc()' an
   check was added as that additional argument: 'TARGET_ABI_BITS == 64'.

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
---
 linux-user/syscall.c | 55 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 46 insertions(+), 9 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 8f63a46f58..44a13c5ec2 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1253,7 +1253,8 @@ static inline abi_long target_to_host_timespec(struct timespec *host_ts,
 #endif
 
 #if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64) || \
-    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64)
+    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64) || \
+    defined(TARGET_NR_utimensat_time64) || defined(TARGET_NR_semtimedop_time64)
 static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
                                                  abi_ulong target_addr)
 {
@@ -3886,7 +3887,7 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
 }
 
 #if defined(TARGET_NR_ipc) || defined(TARGET_NR_semop) || \
-    defined(TARGET_NR_semtimedop)
+    defined(TARGET_NR_semtimedop) || defined(TARGET_NR_semtimedop_time64)
 
 /*
  * This macro is required to handle the s390 variants, which passes the
@@ -3903,7 +3904,7 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
 static inline abi_long do_semtimedop(int semid,
                                      abi_long ptr,
                                      unsigned nsops,
-                                     abi_long timeout)
+                                     abi_long timeout, int time64)
 {
     struct sembuf sops[nsops];
     struct timespec ts, *pts = NULL;
@@ -3911,7 +3912,10 @@ static inline abi_long do_semtimedop(int semid,
 
     if (timeout) {
         pts = &ts;
-        if (target_to_host_timespec(pts, timeout)) {
+        if (!time64 && target_to_host_timespec(pts, timeout)) {
+            return -TARGET_EFAULT;
+        }
+        if (time64 && target_to_host_timespec64(pts, timeout)) {
             return -TARGET_EFAULT;
         }
     }
@@ -4426,7 +4430,7 @@ static abi_long do_ipc(CPUArchState *cpu_env,
 
     switch (call) {
     case IPCOP_semop:
-        ret = do_semtimedop(first, ptr, second, 0);
+        ret = do_semtimedop(first, ptr, second, 0, 0);
         break;
     case IPCOP_semtimedop:
     /*
@@ -4436,9 +4440,9 @@ static abi_long do_ipc(CPUArchState *cpu_env,
      * to a struct timespec where the generic variant uses fifth parameter.
      */
 #if defined(TARGET_S390X)
-        ret = do_semtimedop(first, ptr, second, third);
+        ret = do_semtimedop(first, ptr, second, third, TARGET_ABI_BITS == 64);
 #else
-        ret = do_semtimedop(first, ptr, second, fifth);
+        ret = do_semtimedop(first, ptr, second, fifth, TARGET_ABI_BITS == 64);
 #endif
         break;
 
@@ -9783,11 +9787,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_NR_semop
     case TARGET_NR_semop:
-        return do_semtimedop(arg1, arg2, arg3, 0);
+        return do_semtimedop(arg1, arg2, arg3, 0, 0);
 #endif
 #ifdef TARGET_NR_semtimedop
     case TARGET_NR_semtimedop:
-        return do_semtimedop(arg1, arg2, arg3, arg4);
+        return do_semtimedop(arg1, arg2, arg3, arg4, 0);
+#endif
+#ifdef TARGET_NR_semtimedop_time64
+    case TARGET_NR_semtimedop_time64:
+        return do_semtimedop(arg1, arg2, arg3, arg4, 1);
 #endif
 #ifdef TARGET_NR_semctl
     case TARGET_NR_semctl:
@@ -11969,6 +11977,35 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         }
         return ret;
 #endif
+#ifdef TARGET_NR_utimensat_time64
+    case TARGET_NR_utimensat_time64:
+        {
+            struct timespec *tsp, ts[2];
+            if (!arg3) {
+                tsp = NULL;
+            } else {
+                if (target_to_host_timespec64(ts, arg3)) {
+                    return -TARGET_EFAULT;
+                }
+                if (target_to_host_timespec64(ts + 1, arg3 +
+                                     sizeof(struct target__kernel_timespec))) {
+                    return -TARGET_EFAULT;
+                }
+                tsp = ts;
+            }
+            if (!arg2)
+                ret = get_errno(sys_utimensat(arg1, NULL, tsp, arg4));
+            else {
+                p = lock_user_string(arg2);
+                if (!p) {
+                    return -TARGET_EFAULT;
+                }
+                ret = get_errno(sys_utimensat(arg1, path(p), tsp, arg4));
+                unlock_user(p, arg2, 0);
+            }
+        }
+        return ret;
+#endif
 #ifdef TARGET_NR_futex
     case TARGET_NR_futex:
         return do_futex(arg1, arg2, arg3, arg4, arg5, arg6);
-- 
2.25.1

Re: [PATCH 2/2] linux-user: Add support for 'utimensat_time64()' and 'semtimedop_time64()'

[Laurent Vivier]

Le 12/08/2020 à 15:57, Filip Bozuta a écrit :
> This patch introduces functionality for following time64 syscalls:
> 
> *utimensat_time64()
> 
>     int utimensat(int dirfd, const char *pathname,
>                   const struct timespec times[2], int flags);
>     -- change file timestamps with nanosecond precision --
>     man page: https://man7.org/linux/man-pages/man2/utimensat.2.html
> 
> *semtimedop_time64()
> 
>     int semtimedop(int semid, struct sembuf *sops, size_t nsops,
>                    const struct timespec *timeout);
>     -- System V semaphore operations --
>     man page: https://www.man7.org/linux/man-pages/man2/semtimedop.2.html
> 
> Implementation notes:
> 
>    Syscall 'utimensat_time64()' is implemented in similar way as its
>    regular variants only difference being that time64 converting function
>    is used to convert values of 'struct timespec' between host and target
>    ('target_to_host_timespec64()').
> 
>    For syscall 'semtimedop_time64()' and additional argument is added
>    in function 'do_semtimedop()' through which the aproppriate 'struct timespec'
>    converting function is called (0 for regular target_to_host_timespec()
>    and anything else for target_to_host_timespec64()). For 'do_ipc()' an
>    check was added as that additional argument: 'TARGET_ABI_BITS == 64'.
> 
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
>  linux-user/syscall.c | 55 ++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 46 insertions(+), 9 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 8f63a46f58..44a13c5ec2 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -1253,7 +1253,8 @@ static inline abi_long target_to_host_timespec(struct timespec *host_ts,
>  #endif
>  
>  #if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64) || \
> -    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64)
> +    defined(TARGET_NR_pselect6_time64) || defined(TARGET_NR_ppoll_time64) || \
> +    defined(TARGET_NR_utimensat_time64) || defined(TARGET_NR_semtimedop_time64)
>  static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
>                                                   abi_ulong target_addr)
>  {
> @@ -3886,7 +3887,7 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
>  }
>  
>  #if defined(TARGET_NR_ipc) || defined(TARGET_NR_semop) || \
> -    defined(TARGET_NR_semtimedop)
> +    defined(TARGET_NR_semtimedop) || defined(TARGET_NR_semtimedop_time64)
>  
>  /*
>   * This macro is required to handle the s390 variants, which passes the
> @@ -3903,7 +3904,7 @@ static inline abi_long target_to_host_sembuf(struct sembuf *host_sembuf,
>  static inline abi_long do_semtimedop(int semid,
>                                       abi_long ptr,
>                                       unsigned nsops,
> -                                     abi_long timeout)
> +                                     abi_long timeout, int time64)

"bool time64" would be cleaner

>  {
>      struct sembuf sops[nsops];
>      struct timespec ts, *pts = NULL;
> @@ -3911,7 +3912,10 @@ static inline abi_long do_semtimedop(int semid,
>  
>      if (timeout) {
>          pts = &ts;
> -        if (target_to_host_timespec(pts, timeout)) {
> +        if (!time64 && target_to_host_timespec(pts, timeout)) {
> +            return -TARGET_EFAULT;
> +        }
> +        if (time64 && target_to_host_timespec64(pts, timeout)) {
>              return -TARGET_EFAULT;
>          }

why not:

    if (time64) {
        if (target_to_host_timespec64(pts, timeout)) {
            return -TARGET_EFAULT;
        }
    } else {
        if (target_to_host_timespec(pts, timeout)) {
              return -TARGET_EFAULT;
        }
    }

I think it's clearer.

With that fixed:

Reviewed-by: Laurent Vivier <laurent@vivier.eu>