[RFC,3/12] mach, hurd: Cast through uintptr_t
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Commit Message
When casting between a pointer and an integer of a different size, GCC
emits a warning (which is escalated to a build failure by -Werror).
Indeed, if what you start with is a pointer, which you then cast to a
shorter integer and then back again, you're going to cut off some bits
of the pointer.
But if you start with an integer (such as mach_port_t), then cast it to
a longer pointer (void *), and then back to a shorter integer, you are
fine. To keep GCC happy, cast through an intermediary uintptr_t, which
is always the same size as a pointer.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
htl/cthreads-compat.c | 5 +++--
hurd/fopenport.c | 15 ++++++++++-----
hurd/hurd/port.h | 2 +-
hurd/port-cleanup.c | 3 ++-
hurd/vpprintf.c | 6 ++++--
mach/devstream.c | 9 +++++----
6 files changed, 25 insertions(+), 15 deletions(-)
Comments
Applied, thanks!
Sergey Bugaev, le dim. 12 févr. 2023 14:10:34 +0300, a ecrit:
> When casting between a pointer and an integer of a different size, GCC
> emits a warning (which is escalated to a build failure by -Werror).
> Indeed, if what you start with is a pointer, which you then cast to a
> shorter integer and then back again, you're going to cut off some bits
> of the pointer.
>
> But if you start with an integer (such as mach_port_t), then cast it to
> a longer pointer (void *), and then back to a shorter integer, you are
> fine. To keep GCC happy, cast through an intermediary uintptr_t, which
> is always the same size as a pointer.
>
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
> htl/cthreads-compat.c | 5 +++--
> hurd/fopenport.c | 15 ++++++++++-----
> hurd/hurd/port.h | 2 +-
> hurd/port-cleanup.c | 3 ++-
> hurd/vpprintf.c | 6 ++++--
> mach/devstream.c | 9 +++++----
> 6 files changed, 25 insertions(+), 15 deletions(-)
>
> diff --git a/htl/cthreads-compat.c b/htl/cthreads-compat.c
> index 55043a8b..2a0a95b6 100644
> --- a/htl/cthreads-compat.c
> +++ b/htl/cthreads-compat.c
> @@ -25,8 +25,9 @@ void
> __cthread_detach (__cthread_t thread)
> {
> int err;
> + pthread_t pthread = (pthread_t) (uintptr_t) thread;
>
> - err = __pthread_detach ((pthread_t) thread);
> + err = __pthread_detach (pthread);
> assert_perror (err);
> }
> weak_alias (__cthread_detach, cthread_detach)
> @@ -40,7 +41,7 @@ __cthread_fork (__cthread_fn_t func, void *arg)
> err = __pthread_create (&thread, NULL, func, arg);
> assert_perror (err);
>
> - return (__cthread_t) thread;
> + return (__cthread_t) (uintptr_t) thread;
> }
> weak_alias (__cthread_fork, cthread_fork)
>
> diff --git a/hurd/fopenport.c b/hurd/fopenport.c
> index 60afb445..be6aa30c 100644
> --- a/hurd/fopenport.c
> +++ b/hurd/fopenport.c
> @@ -28,9 +28,10 @@ readio (void *cookie, char *buf, size_t n)
> mach_msg_type_number_t nread;
> error_t err;
> char *bufp = buf;
> + io_t io = (io_t) (uintptr_t) cookie;
>
> nread = n;
> - if (err = __io_read ((io_t) cookie, &bufp, &nread, -1, n))
> + if (err = __io_read (io, &bufp, &nread, -1, n))
> return __hurd_fail (err);
>
> if (bufp != buf)
> @@ -50,8 +51,9 @@ writeio (void *cookie, const char *buf, size_t n)
> {
> vm_size_t wrote;
> error_t err;
> + io_t io = (io_t) (uintptr_t) cookie;
>
> - if (err = __io_write ((io_t) cookie, buf, n, -1, &wrote))
> + if (err = __io_write (io, buf, n, -1, &wrote))
> return __hurd_fail (err);
>
> return wrote;
> @@ -65,7 +67,8 @@ seekio (void *cookie,
> off64_t *pos,
> int whence)
> {
> - error_t err = __io_seek ((file_t) cookie, *pos, whence, pos);
> + io_t io = (io_t) (uintptr_t) cookie;
> + error_t err = __io_seek (io, *pos, whence, pos);
> return err ? __hurd_fail (err) : 0;
> }
>
> @@ -74,8 +77,9 @@ seekio (void *cookie,
> static int
> closeio (void *cookie)
> {
> + io_t io = (io_t) (uintptr_t) cookie;
> error_t error = __mach_port_deallocate (__mach_task_self (),
> - (mach_port_t) cookie);
> + io);
> if (error)
> return __hurd_fail (error);
> return 0;
> @@ -127,6 +131,7 @@ __fopenport (mach_port_t port, const char *mode)
> return NULL;
> }
>
> - return fopencookie ((void *) port, mode, funcsio);
> + return fopencookie ((void *) (uintptr_t) port,
> + mode, funcsio);
> }
> weak_alias (__fopenport, fopenport)
> diff --git a/hurd/hurd/port.h b/hurd/hurd/port.h
> index fdba8db5..1e473978 100644
> --- a/hurd/hurd/port.h
> +++ b/hurd/hurd/port.h
> @@ -96,7 +96,7 @@ _hurd_port_locked_get (struct hurd_port *port,
> if (result != MACH_PORT_NULL)
> {
> link->cleanup = &_hurd_port_cleanup;
> - link->cleanup_data = (void *) result;
> + link->cleanup_data = (void *) (uintptr_t) result;
> _hurd_userlink_link (&port->users, link);
> }
> __spin_unlock (&port->lock);
> diff --git a/hurd/port-cleanup.c b/hurd/port-cleanup.c
> index 08ab3d47..ad43b830 100644
> --- a/hurd/port-cleanup.c
> +++ b/hurd/port-cleanup.c
> @@ -26,7 +26,8 @@
> void
> _hurd_port_cleanup (void *cleanup_data, jmp_buf env, int val)
> {
> - __mach_port_deallocate (__mach_task_self (), (mach_port_t) cleanup_data);
> + mach_port_t port = (mach_port_t) (uintptr_t) cleanup_data;
> + __mach_port_deallocate (__mach_task_self (), port);
> }
>
> /* We were cancelled while using a port, and called from the cleanup unwinding.
> diff --git a/hurd/vpprintf.c b/hurd/vpprintf.c
> index fe734946..010f04ca 100644
> --- a/hurd/vpprintf.c
> +++ b/hurd/vpprintf.c
> @@ -25,8 +25,9 @@
> static ssize_t
> do_write (void *cookie, const char *buf, size_t n)
> {
> + io_t io = (io_t) (uintptr_t) cookie;
> vm_size_t amount = n;
> - error_t error = __io_write ((io_t) cookie, buf, n, -1, &amount);
> + error_t error = __io_write (io, buf, n, -1, &amount);
> if (error)
> return __hurd_fail (error);
> return n;
> @@ -51,7 +52,8 @@ vpprintf (io_t port, const char *format, va_list arg)
> #endif
>
> _IO_cookie_init (&temp_f.cfile, _IO_NO_READS,
> - (void *) port, (cookie_io_functions_t) { write: do_write });
> + (void *) (uintptr_t) port,
> + (cookie_io_functions_t) { write: do_write });
>
> done = __vfprintf_internal (&temp_f.cfile.__fp.file, format, arg, 0);
>
> diff --git a/mach/devstream.c b/mach/devstream.c
> index 09272d10..cfa9a4f4 100644
> --- a/mach/devstream.c
> +++ b/mach/devstream.c
> @@ -28,7 +28,7 @@
> static ssize_t
> devstream_write (void *cookie, const char *buffer, size_t n)
> {
> - const device_t dev = (device_t) cookie;
> + const device_t dev = (device_t) (uintptr_t) cookie;
>
> int write_some (const char *p, size_t to_write)
> {
> @@ -83,7 +83,7 @@ devstream_write (void *cookie, const char *buffer, size_t n)
> static ssize_t
> devstream_read (void *cookie, char *buffer, size_t to_read)
> {
> - const device_t dev = (device_t) cookie;
> + const device_t dev = (device_t) (uintptr_t) cookie;
>
> kern_return_t err;
> mach_msg_type_number_t nread = to_read;
> @@ -112,7 +112,8 @@ devstream_read (void *cookie, char *buffer, size_t to_read)
> static int
> dealloc_ref (void *cookie)
> {
> - if (__mach_port_deallocate (mach_task_self (), (mach_port_t) cookie))
> + const device_t dev = (device_t) (uintptr_t) cookie;
> + if (__mach_port_deallocate (mach_task_self (), dev))
> {
> errno = EINVAL;
> return -1;
> @@ -131,7 +132,7 @@ mach_open_devstream (mach_port_t dev, const char *mode)
> return NULL;
> }
>
> - stream = _IO_fopencookie ((void *) dev, mode,
> + stream = _IO_fopencookie ((void *) (uintptr_t) dev, mode,
> (cookie_io_functions_t) { write: devstream_write,
> read: devstream_read,
> close: dealloc_ref });
> --
> 2.39.1
>
>
@@ -25,8 +25,9 @@ void
__cthread_detach (__cthread_t thread)
{
int err;
+ pthread_t pthread = (pthread_t) (uintptr_t) thread;
- err = __pthread_detach ((pthread_t) thread);
+ err = __pthread_detach (pthread);
assert_perror (err);
}
weak_alias (__cthread_detach, cthread_detach)
@@ -40,7 +41,7 @@ __cthread_fork (__cthread_fn_t func, void *arg)
err = __pthread_create (&thread, NULL, func, arg);
assert_perror (err);
- return (__cthread_t) thread;
+ return (__cthread_t) (uintptr_t) thread;
}
weak_alias (__cthread_fork, cthread_fork)
@@ -28,9 +28,10 @@ readio (void *cookie, char *buf, size_t n)
mach_msg_type_number_t nread;
error_t err;
char *bufp = buf;
+ io_t io = (io_t) (uintptr_t) cookie;
nread = n;
- if (err = __io_read ((io_t) cookie, &bufp, &nread, -1, n))
+ if (err = __io_read (io, &bufp, &nread, -1, n))
return __hurd_fail (err);
if (bufp != buf)
@@ -50,8 +51,9 @@ writeio (void *cookie, const char *buf, size_t n)
{
vm_size_t wrote;
error_t err;
+ io_t io = (io_t) (uintptr_t) cookie;
- if (err = __io_write ((io_t) cookie, buf, n, -1, &wrote))
+ if (err = __io_write (io, buf, n, -1, &wrote))
return __hurd_fail (err);
return wrote;
@@ -65,7 +67,8 @@ seekio (void *cookie,
off64_t *pos,
int whence)
{
- error_t err = __io_seek ((file_t) cookie, *pos, whence, pos);
+ io_t io = (io_t) (uintptr_t) cookie;
+ error_t err = __io_seek (io, *pos, whence, pos);
return err ? __hurd_fail (err) : 0;
}
@@ -74,8 +77,9 @@ seekio (void *cookie,
static int
closeio (void *cookie)
{
+ io_t io = (io_t) (uintptr_t) cookie;
error_t error = __mach_port_deallocate (__mach_task_self (),
- (mach_port_t) cookie);
+ io);
if (error)
return __hurd_fail (error);
return 0;
@@ -127,6 +131,7 @@ __fopenport (mach_port_t port, const char *mode)
return NULL;
}
- return fopencookie ((void *) port, mode, funcsio);
+ return fopencookie ((void *) (uintptr_t) port,
+ mode, funcsio);
}
weak_alias (__fopenport, fopenport)
@@ -96,7 +96,7 @@ _hurd_port_locked_get (struct hurd_port *port,
if (result != MACH_PORT_NULL)
{
link->cleanup = &_hurd_port_cleanup;
- link->cleanup_data = (void *) result;
+ link->cleanup_data = (void *) (uintptr_t) result;
_hurd_userlink_link (&port->users, link);
}
__spin_unlock (&port->lock);
@@ -26,7 +26,8 @@
void
_hurd_port_cleanup (void *cleanup_data, jmp_buf env, int val)
{
- __mach_port_deallocate (__mach_task_self (), (mach_port_t) cleanup_data);
+ mach_port_t port = (mach_port_t) (uintptr_t) cleanup_data;
+ __mach_port_deallocate (__mach_task_self (), port);
}
/* We were cancelled while using a port, and called from the cleanup unwinding.
@@ -25,8 +25,9 @@
static ssize_t
do_write (void *cookie, const char *buf, size_t n)
{
+ io_t io = (io_t) (uintptr_t) cookie;
vm_size_t amount = n;
- error_t error = __io_write ((io_t) cookie, buf, n, -1, &amount);
+ error_t error = __io_write (io, buf, n, -1, &amount);
if (error)
return __hurd_fail (error);
return n;
@@ -51,7 +52,8 @@ vpprintf (io_t port, const char *format, va_list arg)
#endif
_IO_cookie_init (&temp_f.cfile, _IO_NO_READS,
- (void *) port, (cookie_io_functions_t) { write: do_write });
+ (void *) (uintptr_t) port,
+ (cookie_io_functions_t) { write: do_write });
done = __vfprintf_internal (&temp_f.cfile.__fp.file, format, arg, 0);
@@ -28,7 +28,7 @@
static ssize_t
devstream_write (void *cookie, const char *buffer, size_t n)
{
- const device_t dev = (device_t) cookie;
+ const device_t dev = (device_t) (uintptr_t) cookie;
int write_some (const char *p, size_t to_write)
{
@@ -83,7 +83,7 @@ devstream_write (void *cookie, const char *buffer, size_t n)
static ssize_t
devstream_read (void *cookie, char *buffer, size_t to_read)
{
- const device_t dev = (device_t) cookie;
+ const device_t dev = (device_t) (uintptr_t) cookie;
kern_return_t err;
mach_msg_type_number_t nread = to_read;
@@ -112,7 +112,8 @@ devstream_read (void *cookie, char *buffer, size_t to_read)
static int
dealloc_ref (void *cookie)
{
- if (__mach_port_deallocate (mach_task_self (), (mach_port_t) cookie))
+ const device_t dev = (device_t) (uintptr_t) cookie;
+ if (__mach_port_deallocate (mach_task_self (), dev))
{
errno = EINVAL;
return -1;
@@ -131,7 +132,7 @@ mach_open_devstream (mach_port_t dev, const char *mode)
return NULL;
}
- stream = _IO_fopencookie ((void *) dev, mode,
+ stream = _IO_fopencookie ((void *) (uintptr_t) dev, mode,
(cookie_io_functions_t) { write: devstream_write,
read: devstream_read,
close: dealloc_ref });