[Qemu-devel] [PATCH 0/4] linux-user: fix timespec and itimerspec related issues, add clock_settime

[Qemu-devel] [PATCH 0/4] linux-user: fix timespec and itimerspec related issues, add clock_settime

[Dejan Jovicevic]

In this series the clock_gettime() was fixed to behave as intended when not
having valid arguments. The emulation for the system call clock_settime()
was added. Conversion of itimerspec structure and error handling in
timer_settime() syscall were corrected.

Dejan Jovicevic (4):
  linux-user: fix clock_gettime()
  linux-user: add clock_settime()
  linux-user: correct conversion of itimerspec structure
  linux-user: timer_settime fix

 linux-user/syscall.c | 62 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 37 insertions(+), 25 deletions(-)

-- 
1.9.1

[Qemu-devel] [PATCH 1/4] linux-user: fix clock_gettime()

[Dejan Jovicevic]

When timespec stucture pointer points outside the accessible
address space (i.e. it's an invalid pointer), the clock_gettime()
syscall should return with -1 and set the errno to EFAULT.
This wasn't the case, since there was no check if the
host_to_target_timespec() failed. This check was added and
now the syscall behaves appropriately in this situation.

Signed-off-by: Dejan Jovicevic <dejan.jovicevic@rt-rk.com>
---
 linux-user/syscall.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 03339ba..e6abfc5 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -11247,7 +11247,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         struct timespec ts;
         ret = get_errno(clock_gettime(arg1, &ts));
         if (!is_error(ret)) {
-            host_to_target_timespec(arg2, &ts);
+            if (host_to_target_timespec(arg2, &ts)) {
+                goto efault;
+            }
         }
         break;
     }
-- 
1.9.1

[Qemu-devel] [PATCH 2/4] linux-user: add clock_settime()

[Dejan Jovicevic]

The implementation of the clock_settime() system call emulation
is based on converting the timespec structure values from
target to host and then calling the clock_settime() syscall on
the host.

Signed-off-by: Dejan Jovicevic <dejan.jovicevic@rt-rk.com>
---
 linux-user/syscall.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e6abfc5..898f774 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -11254,6 +11254,17 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         break;
     }
 #endif
+#ifdef TARGET_NR_clock_settime
+    case TARGET_NR_clock_settime:
+    {
+        struct timespec ts;
+        if (target_to_host_timespec(&ts, arg2)) {
+            goto efault;
+        }
+        ret = get_errno(clock_settime(arg1, &ts));
+        break;
+    }
+#endif
 #ifdef TARGET_NR_clock_getres
     case TARGET_NR_clock_getres:
     {
-- 
1.9.1

[Qemu-devel] [PATCH 3/4] linux-user: correct conversion of itimerspec structure

[Dejan Jovicevic]

__get_user() and __put_user() have certain advantages over
tswapal(). There was also a previous commit for equivalent
change for converting structure timespec.

Signed-off-by: Dejan Jovicevic <dejan.jovicevic@rt-rk.com>
---
 linux-user/syscall.c | 39 +++++++++++++++++----------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 898f774..b4f53b1 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6731,42 +6731,37 @@ static inline abi_long host_to_target_timespec(abi_ulong target_addr,
     return 0;
 }
 
-static inline abi_long target_to_host_itimerspec(struct itimerspec *host_itspec,
+static inline abi_long target_to_host_itimerspec(struct itimerspec *host_its,
                                                  abi_ulong target_addr)
 {
-    struct target_itimerspec *target_itspec;
+    struct target_itimerspec *target_its;
 
-    if (!lock_user_struct(VERIFY_READ, target_itspec, target_addr, 1)) {
+    if (!lock_user_struct(VERIFY_READ, target_its, target_addr, 1)) {
         return -TARGET_EFAULT;
     }
-
-    host_itspec->it_interval.tv_sec =
-                            tswapal(target_itspec->it_interval.tv_sec);
-    host_itspec->it_interval.tv_nsec =
-                            tswapal(target_itspec->it_interval.tv_nsec);
-    host_itspec->it_value.tv_sec = tswapal(target_itspec->it_value.tv_sec);
-    host_itspec->it_value.tv_nsec = tswapal(target_itspec->it_value.tv_nsec);
-
-    unlock_user_struct(target_itspec, target_addr, 1);
+    __get_user(host_its->it_interval.tv_sec, &target_its->it_interval.tv_sec);
+    __get_user(host_its->it_interval.tv_nsec,
+                               &target_its->it_interval.tv_nsec);
+    __get_user(host_its->it_value.tv_sec, &target_its->it_value.tv_sec);
+    __get_user(host_its->it_value.tv_nsec, &target_its->it_value.tv_nsec);
+    unlock_user_struct(target_its, target_addr, 1);
     return 0;
 }
 
 static inline abi_long host_to_target_itimerspec(abi_ulong target_addr,
                                                struct itimerspec *host_its)
 {
-    struct target_itimerspec *target_itspec;
+    struct target_itimerspec *target_its;
 
-    if (!lock_user_struct(VERIFY_WRITE, target_itspec, target_addr, 0)) {
+    if (!lock_user_struct(VERIFY_WRITE, target_its, target_addr, 0)) {
         return -TARGET_EFAULT;
     }
-
-    target_itspec->it_interval.tv_sec = tswapal(host_its->it_interval.tv_sec);
-    target_itspec->it_interval.tv_nsec = tswapal(host_its->it_interval.tv_nsec);
-
-    target_itspec->it_value.tv_sec = tswapal(host_its->it_value.tv_sec);
-    target_itspec->it_value.tv_nsec = tswapal(host_its->it_value.tv_nsec);
-
-    unlock_user_struct(target_itspec, target_addr, 0);
+    __put_user(host_its->it_interval.tv_sec, &target_its->it_interval.tv_sec);
+    __put_user(host_its->it_interval.tv_nsec,
+                               &target_its->it_interval.tv_nsec);
+    __put_user(host_its->it_value.tv_sec, &target_its->it_value.tv_sec);
+    __put_user(host_its->it_value.tv_nsec, &target_its->it_value.tv_nsec);
+    unlock_user_struct(target_its, target_addr, 0);
     return 0;
 }
 
-- 
1.9.1

[Qemu-devel] [PATCH 4/4] linux-user: timer_settime fix

[Dejan Jovicevic]

Error handling was improved. host_to_target_itimerspec() was
invoked with arg2 passed instead of arg4.

Signed-off-by: Dejan Jovicevic <dejan.jovicevic@rt-rk.com>
---
 linux-user/syscall.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index b4f53b1..cad4269 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -11823,10 +11823,14 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
             timer_t htimer = g_posix_timers[timerid];
             struct itimerspec hspec_new = {{0},}, hspec_old = {{0},};
 
-            target_to_host_itimerspec(&hspec_new, arg3);
+            if (target_to_host_itimerspec(&hspec_new, arg3)) {
+                goto efault;
+            }
             ret = get_errno(
                           timer_settime(htimer, arg2, &hspec_new, &hspec_old));
-            host_to_target_itimerspec(arg2, &hspec_old);
+            if (host_to_target_itimerspec(arg4, &hspec_old)) {
+                goto efault;
+            }
         }
         break;
     }
-- 
1.9.1