[PULL 5/6] linux-user: Add support for a group of 2038 safe syscalls

[Laurent Vivier]

From: Filip Bozuta <Filip.Bozuta@syrmia.com>

This patch implements functionality for following time64 syscalls:

*clock_getres_time64

     This a year 2038 safe variant of syscall:

     int clock_getres(clockid_t clockid, struct timespec *res)
     --finding the resoultion of a specified clock--
     man page: https://man7.org/linux/man-pages/man2/clock_getres.2.html

*timer_gettime64
*timer_settime64

     These are year 2038 safe variants of syscalls:

     int timer_settime(timer_t timerid, int flags,
                       const struct itimerspec *new_value,
                       struct itimerspec *old_value)
     int timer_gettime(timer_t timerid, struct itimerspec *curr_value)
     --arming/dissarming and fetching state of POSIX per-process timer--
     man page: https://man7.org/linux/man-pages/man2/timer_settime.2.html

*timerfd_gettime64
*timerfd_settime64

     These are year 2038 safe variants of syscalls:

     int timerfd_settime(int fd, int flags,
                         const struct itimerspec *new_value,
                         struct itimerspec *old_value)
     int timerfd_gettime(int fd, struct itimerspec *curr_value)
     --timers that notify via file descriptor--
     man page: https://man7.org/linux/man-pages/man2/timerfd_settime.2.html

Implementation notes:

     Syscall 'clock_getres_time64' was implemented similarly to 
'clock_getres()'.
     The only difference was that for the conversion of 'struct timespec' from
     host to target, function 'host_to_target_timespec64()' was used instead of
     'host_to_target_timespec()'.

     For other syscalls, new functions 'host_to_target_itimerspec64()' and
     'target_to_host_itimerspec64()' were added to convert the value of the
     'struct itimerspec' from host to target and vice versa. A new type
     'struct target__kernel_itimerspec' was added in 'syscall_defs.h'. This
     type was defined with fields which are of the already defined type
     'struct target_timespec'. This new 'struct target__kernel_itimerspec'
     type is used in these new converting functions. These new functions were
     defined similarly to 'host_to_target_itimerspec()' and 
'target_to_host_itimerspec()'
     the only difference being that 'target_to_host_timespec64()' and
     'host_to_target_timespec64()' were used.

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200722153421.295411-3-Filip.Bozuta@syrmia.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/syscall.c      | 139 +++++++++++++++++++++++++++++++++++++-
 linux-user/syscall_defs.h |   5 ++
 2 files changed, 143 insertions(+), 1 deletion(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index aea1160804a2..bbb61a59c72f 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1247,7 +1247,9 @@ 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_timer_settime64) || \
+    (defined(TARGET_NR_timerfd_settime64) && defined(CONFIG_TIMERFD))
 static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
                                                  abi_ulong target_addr)
 {
@@ -6801,6 +6803,24 @@ static inline abi_long target_to_host_itimerspec(struct 
itimerspec *host_its,
 }
 #endif
 
+#if defined(TARGET_NR_timer_settime64) || \
+    (defined(TARGET_NR_timerfd_settime64) && defined(CONFIG_TIMERFD))
+static inline abi_long target_to_host_itimerspec64(struct itimerspec *host_its,
+                                                   abi_ulong target_addr)
+{
+    if (target_to_host_timespec64(&host_its->it_interval, target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_interval)) ||
+        target_to_host_timespec64(&host_its->it_value, target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_value))) {
+        return -TARGET_EFAULT;
+    }
+
+    return 0;
+}
+#endif
+
 #if ((defined(TARGET_NR_timerfd_gettime) || \
       defined(TARGET_NR_timerfd_settime)) && defined(CONFIG_TIMERFD)) || \
       defined(TARGET_NR_timer_gettime) || defined(TARGET_NR_timer_settime)
@@ -6819,6 +6839,26 @@ static inline abi_long 
host_to_target_itimerspec(abi_ulong target_addr,
 }
 #endif
 
+#if ((defined(TARGET_NR_timerfd_gettime64) || \
+      defined(TARGET_NR_timerfd_settime64)) && defined(CONFIG_TIMERFD)) || \
+      defined(TARGET_NR_timer_gettime64) || defined(TARGET_NR_timer_settime64)
+static inline abi_long host_to_target_itimerspec64(abi_ulong target_addr,
+                                                   struct itimerspec *host_its)
+{
+    if (host_to_target_timespec64(target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_interval),
+                                  &host_its->it_interval) ||
+        host_to_target_timespec64(target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_value),
+                                  &host_its->it_value)) {
+        return -TARGET_EFAULT;
+    }
+    return 0;
+}
+#endif
+
 #if defined(TARGET_NR_adjtimex) || \
     (defined(TARGET_NR_clock_adjtime) && defined(CONFIG_CLOCK_ADJTIME))
 static inline abi_long target_to_host_timex(struct timex *host_tx,
@@ -11811,6 +11851,17 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
         return ret;
     }
 #endif
+#ifdef TARGET_NR_clock_getres_time64
+    case TARGET_NR_clock_getres_time64:
+    {
+        struct timespec ts;
+        ret = get_errno(clock_getres(arg1, &ts));
+        if (!is_error(ret)) {
+            host_to_target_timespec64(arg2, &ts);
+        }
+        return ret;
+    }
+#endif
 #ifdef TARGET_NR_clock_nanosleep
     case TARGET_NR_clock_nanosleep:
     {
@@ -12405,6 +12456,32 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
     }
 #endif
 
+#ifdef TARGET_NR_timer_settime64
+    case TARGET_NR_timer_settime64:
+    {
+        target_timer_t timerid = get_timer_id(arg1);
+
+        if (timerid < 0) {
+            ret = timerid;
+        } else if (arg3 == 0) {
+            ret = -TARGET_EINVAL;
+        } else {
+            timer_t htimer = g_posix_timers[timerid];
+            struct itimerspec hspec_new = {{0},}, hspec_old = {{0},};
+
+            if (target_to_host_itimerspec64(&hspec_new, arg3)) {
+                return -TARGET_EFAULT;
+            }
+            ret = get_errno(
+                          timer_settime(htimer, arg2, &hspec_new, &hspec_old));
+            if (arg4 && host_to_target_itimerspec64(arg4, &hspec_old)) {
+                return -TARGET_EFAULT;
+            }
+        }
+        return ret;
+    }
+#endif
+
 #ifdef TARGET_NR_timer_gettime
     case TARGET_NR_timer_gettime:
     {
@@ -12428,6 +12505,29 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
     }
 #endif
 
+#ifdef TARGET_NR_timer_gettime64
+    case TARGET_NR_timer_gettime64:
+    {
+        /* args: timer_t timerid, struct itimerspec64 *curr_value */
+        target_timer_t timerid = get_timer_id(arg1);
+
+        if (timerid < 0) {
+            ret = timerid;
+        } else if (!arg2) {
+            ret = -TARGET_EFAULT;
+        } else {
+            timer_t htimer = g_posix_timers[timerid];
+            struct itimerspec hspec;
+            ret = get_errno(timer_gettime(htimer, &hspec));
+
+            if (host_to_target_itimerspec64(arg2, &hspec)) {
+                ret = -TARGET_EFAULT;
+            }
+        }
+        return ret;
+    }
+#endif
+
 #ifdef TARGET_NR_timer_getoverrun
     case TARGET_NR_timer_getoverrun:
     {
@@ -12481,6 +12581,20 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
         return ret;
 #endif
 
+#if defined(TARGET_NR_timerfd_gettime64) && defined(CONFIG_TIMERFD)
+    case TARGET_NR_timerfd_gettime64:
+        {
+            struct itimerspec its_curr;
+
+            ret = get_errno(timerfd_gettime(arg1, &its_curr));
+
+            if (arg2 && host_to_target_itimerspec64(arg2, &its_curr)) {
+                return -TARGET_EFAULT;
+            }
+        }
+        return ret;
+#endif
+
 #if defined(TARGET_NR_timerfd_settime) && defined(CONFIG_TIMERFD)
     case TARGET_NR_timerfd_settime:
         {
@@ -12504,6 +12618,29 @@ static abi_long do_syscall1(void *cpu_env, int num, 
abi_long arg1,
         return ret;
 #endif
 
+#if defined(TARGET_NR_timerfd_settime64) && defined(CONFIG_TIMERFD)
+    case TARGET_NR_timerfd_settime64:
+        {
+            struct itimerspec its_new, its_old, *p_new;
+
+            if (arg3) {
+                if (target_to_host_itimerspec64(&its_new, arg3)) {
+                    return -TARGET_EFAULT;
+                }
+                p_new = &its_new;
+            } else {
+                p_new = NULL;
+            }
+
+            ret = get_errno(timerfd_settime(arg1, arg2, p_new, &its_old));
+
+            if (arg4 && host_to_target_itimerspec64(arg4, &its_old)) {
+                return -TARGET_EFAULT;
+            }
+        }
+        return ret;
+#endif
+
 #if defined(TARGET_NR_ioprio_get) && defined(__NR_ioprio_get)
     case TARGET_NR_ioprio_get:
         return get_errno(ioprio_get(arg1, arg2));
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 3c261cff0e5e..427a25f5bce5 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -259,6 +259,11 @@ struct target_itimerspec {
     struct target_timespec it_value;
 };
 
+struct target__kernel_itimerspec {
+    struct target__kernel_timespec it_interval;
+    struct target__kernel_timespec it_value;
+};
+
 struct target_timex {
     abi_uint modes;              /* Mode selector */
     abi_long offset;             /* Time offset */
-- 
2.26.2