diff mbox series

linux-user: Remove pointless NULL check in clock_adjtime handling

Message ID 20230623144410.1837261-1-peter.maydell@linaro.org
State Superseded
Headers show
Series linux-user: Remove pointless NULL check in clock_adjtime handling | expand

Commit Message

Peter Maydell June 23, 2023, 2:44 p.m. UTC
In the code for TARGET_NR_clock_adjtime, we set the pointer phtx to
the address of the local variable htx.  This means it can never be
NULL, but later in the code we check it for NULL anyway.  Coverity
complains about this (CID 1507683) because the NULL check comes after
a call to clock_adjtime() that assumes it is non-NULL.

Since phtx is always &htx, and is used only in three places, it's not
really necessary.  Remove it, bringing the code structure in to line
with that for TARGET_NR_clock_adjtime64, which already uses a simple
'&htx' when it wants a pointer to 'htx'.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/syscall.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Comments

Philippe Mathieu-Daudé June 23, 2023, 3:18 p.m. UTC | #1
On 23/6/23 16:44, Peter Maydell wrote:
> In the code for TARGET_NR_clock_adjtime, we set the pointer phtx to
> the address of the local variable htx.  This means it can never be
> NULL, but later in the code we check it for NULL anyway.  Coverity
> complains about this (CID 1507683) because the NULL check comes after
> a call to clock_adjtime() that assumes it is non-NULL.
> 
> Since phtx is always &htx, and is used only in three places, it's not
> really necessary.  Remove it, bringing the code structure in to line
> with that for TARGET_NR_clock_adjtime64, which already uses a simple
> '&htx' when it wants a pointer to 'htx'.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   linux-user/syscall.c | 12 +++++-------
>   1 file changed, 5 insertions(+), 7 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Richard Henderson June 26, 2023, 8:27 a.m. UTC | #2
On 6/23/23 16:44, Peter Maydell wrote:
> In the code for TARGET_NR_clock_adjtime, we set the pointer phtx to
> the address of the local variable htx.  This means it can never be
> NULL, but later in the code we check it for NULL anyway.  Coverity
> complains about this (CID 1507683) because the NULL check comes after
> a call to clock_adjtime() that assumes it is non-NULL.
> 
> Since phtx is always &htx, and is used only in three places, it's not
> really necessary.  Remove it, bringing the code structure in to line
> with that for TARGET_NR_clock_adjtime64, which already uses a simple
> '&htx' when it wants a pointer to 'htx'.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   linux-user/syscall.c | 12 +++++-------
>   1 file changed, 5 insertions(+), 7 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
Peter Maydell July 4, 2023, 1:26 p.m. UTC | #3
Laurent, ping? This patch has been reviewed.

thanks
-- PMM

On Fri, 23 Jun 2023 at 15:44, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In the code for TARGET_NR_clock_adjtime, we set the pointer phtx to
> the address of the local variable htx.  This means it can never be
> NULL, but later in the code we check it for NULL anyway.  Coverity
> complains about this (CID 1507683) because the NULL check comes after
> a call to clock_adjtime() that assumes it is non-NULL.
>
> Since phtx is always &htx, and is used only in three places, it's not
> really necessary.  Remove it, bringing the code structure in to line
> with that for TARGET_NR_clock_adjtime64, which already uses a simple
> '&htx' when it wants a pointer to 'htx'.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  linux-user/syscall.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index f2cb101d83c..7b2f9f7340e 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -10935,16 +10935,14 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
>  #if defined(TARGET_NR_clock_adjtime) && defined(CONFIG_CLOCK_ADJTIME)
>      case TARGET_NR_clock_adjtime:
>          {
> -            struct timex htx, *phtx = &htx;
> +            struct timex htx;
>
> -            if (target_to_host_timex(phtx, arg2) != 0) {
> +            if (target_to_host_timex(&htx, arg2) != 0) {
>                  return -TARGET_EFAULT;
>              }
> -            ret = get_errno(clock_adjtime(arg1, phtx));
> -            if (!is_error(ret) && phtx) {
> -                if (host_to_target_timex(arg2, phtx) != 0) {
> -                    return -TARGET_EFAULT;
> -                }
> +            ret = get_errno(clock_adjtime(arg1, &htx));
> +            if (!is_error(ret) && host_to_target_timex(arg2, &htx)) {
> +                return -TARGET_EFAULT;
>              }
>          }
>          return ret;
> --
Peter Maydell July 13, 2023, 1:10 p.m. UTC | #4
I'll take this via target-arm.next unless there are any
objections...

thanks
-- PMM

On Tue, 4 Jul 2023 at 14:26, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> Laurent, ping? This patch has been reviewed.
>
> thanks
> -- PMM
>
> On Fri, 23 Jun 2023 at 15:44, Peter Maydell <peter.maydell@linaro.org> wrote:
> >
> > In the code for TARGET_NR_clock_adjtime, we set the pointer phtx to
> > the address of the local variable htx.  This means it can never be
> > NULL, but later in the code we check it for NULL anyway.  Coverity
> > complains about this (CID 1507683) because the NULL check comes after
> > a call to clock_adjtime() that assumes it is non-NULL.
> >
> > Since phtx is always &htx, and is used only in three places, it's not
> > really necessary.  Remove it, bringing the code structure in to line
> > with that for TARGET_NR_clock_adjtime64, which already uses a simple
> > '&htx' when it wants a pointer to 'htx'.
> >
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > ---
> >  linux-user/syscall.c | 12 +++++-------
> >  1 file changed, 5 insertions(+), 7 deletions(-)
> >
> > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > index f2cb101d83c..7b2f9f7340e 100644
> > --- a/linux-user/syscall.c
> > +++ b/linux-user/syscall.c
> > @@ -10935,16 +10935,14 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
> >  #if defined(TARGET_NR_clock_adjtime) && defined(CONFIG_CLOCK_ADJTIME)
> >      case TARGET_NR_clock_adjtime:
> >          {
> > -            struct timex htx, *phtx = &htx;
> > +            struct timex htx;
> >
> > -            if (target_to_host_timex(phtx, arg2) != 0) {
> > +            if (target_to_host_timex(&htx, arg2) != 0) {
> >                  return -TARGET_EFAULT;
> >              }
> > -            ret = get_errno(clock_adjtime(arg1, phtx));
> > -            if (!is_error(ret) && phtx) {
> > -                if (host_to_target_timex(arg2, phtx) != 0) {
> > -                    return -TARGET_EFAULT;
> > -                }
> > +            ret = get_errno(clock_adjtime(arg1, &htx));
> > +            if (!is_error(ret) && host_to_target_timex(arg2, &htx)) {
> > +                return -TARGET_EFAULT;
> >              }
> >          }
> >          return ret;
> > --
diff mbox series

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index f2cb101d83c..7b2f9f7340e 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -10935,16 +10935,14 @@  static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
 #if defined(TARGET_NR_clock_adjtime) && defined(CONFIG_CLOCK_ADJTIME)
     case TARGET_NR_clock_adjtime:
         {
-            struct timex htx, *phtx = &htx;
+            struct timex htx;
 
-            if (target_to_host_timex(phtx, arg2) != 0) {
+            if (target_to_host_timex(&htx, arg2) != 0) {
                 return -TARGET_EFAULT;
             }
-            ret = get_errno(clock_adjtime(arg1, phtx));
-            if (!is_error(ret) && phtx) {
-                if (host_to_target_timex(arg2, phtx) != 0) {
-                    return -TARGET_EFAULT;
-                }
+            ret = get_errno(clock_adjtime(arg1, &htx));
+            if (!is_error(ret) && host_to_target_timex(arg2, &htx)) {
+                return -TARGET_EFAULT;
             }
         }
         return ret;