emscripten exposes copy_file_range declaration but doesn't provide the
implementation in the final link. Define the emscripten-specific stub
function to avoid type conflict with the emscripten's header.
Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
---
block/file-posix.c | 6 ++++++
stubs/emscripten.c | 13 +++++++++++++
2 files changed, 19 insertions(+)
create mode 100644 stubs/emscripten.c
diff --git a/block/file-posix.c b/block/file-posix.c
index 56d1972d15..22e0ed5069 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -110,6 +110,10 @@
#include <sys/diskslice.h>
#endif
+#ifdef EMSCRIPTEN
+#include <sys/ioctl.h>
+#endif
+
/* OS X does not have O_DSYNC */
#ifndef O_DSYNC
#ifdef O_SYNC
@@ -2010,6 +2014,7 @@ static int handle_aiocb_write_zeroes_unmap(void *opaque)
return handle_aiocb_write_zeroes(aiocb);
}
+#ifndef EMSCRIPTEN
#ifndef HAVE_COPY_FILE_RANGE
static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
off_t *out_off, size_t len, unsigned int flags)
@@ -2023,6 +2028,7 @@ static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
#endif
}
#endif
+#endif
/*
* parse_zone - Fill a zone descriptor
diff --git a/stubs/emscripten.c b/stubs/emscripten.c
new file mode 100644
index 0000000000..2157d6349b
--- /dev/null
+++ b/stubs/emscripten.c
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#include "qemu/osdep.h"
+/*
+ * emscripten exposes copy_file_range declaration but doesn't provide the
+ * implementation in the final link. Define the stub here but avoid type
+ * conflict with the emscripten's header.
+ */
+ssize_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
+ off_t *out_off, size_t len, unsigned int flags)
+{
+ errno = ENOSYS;
+ return -1;
+}
--
2.25.1On 16/4/25 10:14, Kohei Tokunaga wrote:
> emscripten exposes copy_file_range declaration but doesn't provide the
> implementation in the final link. Define the emscripten-specific stub
> function to avoid type conflict with the emscripten's header.
>
> Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
> ---
> block/file-posix.c | 6 ++++++
> stubs/emscripten.c | 13 +++++++++++++
> 2 files changed, 19 insertions(+)
> create mode 100644 stubs/emscripten.c
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 56d1972d15..22e0ed5069 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -110,6 +110,10 @@
> #include <sys/diskslice.h>
> #endif
>
> +#ifdef EMSCRIPTEN
> +#include <sys/ioctl.h>
> +#endif
> +
> /* OS X does not have O_DSYNC */
> #ifndef O_DSYNC
> #ifdef O_SYNC
> @@ -2010,6 +2014,7 @@ static int handle_aiocb_write_zeroes_unmap(void *opaque)
> return handle_aiocb_write_zeroes(aiocb);
> }
>
> +#ifndef EMSCRIPTEN
> #ifndef HAVE_COPY_FILE_RANGE
> static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
> off_t *out_off, size_t len, unsigned int flags)
> @@ -2023,6 +2028,7 @@ static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
> #endif
> }
> #endif
> +#endif
>
> /*
> * parse_zone - Fill a zone descriptor
> diff --git a/stubs/emscripten.c b/stubs/emscripten.c
> new file mode 100644
> index 0000000000..2157d6349b
> --- /dev/null
> +++ b/stubs/emscripten.c
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#include "qemu/osdep.h"
> +/*
> + * emscripten exposes copy_file_range declaration but doesn't provide the
> + * implementation in the final link. Define the stub here but avoid type
> + * conflict with the emscripten's header.
> + */
> +ssize_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
> + off_t *out_off, size_t len, unsigned int flags)
> +{
> + errno = ENOSYS;
> + return -1;
> +}
I'd include in this patch this hunk from patch 17:
-- >8 --
diff --git a/stubs/meson.build b/stubs/meson.build
index 63392f5e78..4fd4d362f9 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -89,3 +89,7 @@ if have_system or have_user
stub_ss.add(files('hotplug-stubs.c'))
stub_ss.add(files('sysbus.c'))
endif
+
+if host_os == 'emscripten'
+ stub_ss.add(files('emscripten.c'))
+endif
---
Hi Philippe,
> I'd include in this patch this hunk from patch 17:
>
> -- >8 --
> diff --git a/stubs/meson.build b/stubs/meson.build
> index 63392f5e78..4fd4d362f9 100644
> --- a/stubs/meson.build
> +++ b/stubs/meson.build
> @@ -89,3 +89,7 @@ if have_system or have_user
> stub_ss.add(files('hotplug-stubs.c'))
> stub_ss.add(files('sysbus.c'))
> endif
> +
> +if host_os == 'emscripten'
> + stub_ss.add(files('emscripten.c'))
> +endif
> ---
Sure, I'll move that hunk into this patch.
On 16/4/25 11:00, Philippe Mathieu-Daudé wrote:
> On 16/4/25 10:14, Kohei Tokunaga wrote:
>> emscripten exposes copy_file_range declaration but doesn't provide the
>> implementation in the final link. Define the emscripten-specific stub
>> function to avoid type conflict with the emscripten's header.
>>
>> Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
>> ---
>> block/file-posix.c | 6 ++++++
>> stubs/emscripten.c | 13 +++++++++++++
>> 2 files changed, 19 insertions(+)
>> create mode 100644 stubs/emscripten.c
>>
>> diff --git a/block/file-posix.c b/block/file-posix.c
>> index 56d1972d15..22e0ed5069 100644
>> --- a/block/file-posix.c
>> +++ b/block/file-posix.c
>> @@ -110,6 +110,10 @@
>> #include <sys/diskslice.h>
>> #endif
>> +#ifdef EMSCRIPTEN
>> +#include <sys/ioctl.h>
>> +#endif
>> +
>> /* OS X does not have O_DSYNC */
>> #ifndef O_DSYNC
>> #ifdef O_SYNC
>> @@ -2010,6 +2014,7 @@ static int handle_aiocb_write_zeroes_unmap(void
>> *opaque)
>> return handle_aiocb_write_zeroes(aiocb);
>> }
>> +#ifndef EMSCRIPTEN
>> #ifndef HAVE_COPY_FILE_RANGE
>> static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
>> off_t *out_off, size_t len, unsigned
>> int flags)
>> @@ -2023,6 +2028,7 @@ static off_t copy_file_range(int in_fd, off_t
>> *in_off, int out_fd,
>> #endif
>> }
>> #endif
>> +#endif
>> /*
>> * parse_zone - Fill a zone descriptor
>> diff --git a/stubs/emscripten.c b/stubs/emscripten.c
>> new file mode 100644
>> index 0000000000..2157d6349b
>> --- /dev/null
>> +++ b/stubs/emscripten.c
>> @@ -0,0 +1,13 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +#include "qemu/osdep.h"
>> +/*
>> + * emscripten exposes copy_file_range declaration but doesn't provide
>> the
>> + * implementation in the final link. Define the stub here but avoid type
>> + * conflict with the emscripten's header.
>> + */
>> +ssize_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
>> + off_t *out_off, size_t len, unsigned int
>> flags)
>> +{
>> + errno = ENOSYS;
>> + return -1;
>> +}
>
> I'd include in this patch this hunk from patch 17:
>
> -- >8 --
> diff --git a/stubs/meson.build b/stubs/meson.build
> index 63392f5e78..4fd4d362f9 100644
> --- a/stubs/meson.build
> +++ b/stubs/meson.build
> @@ -89,3 +89,7 @@ if have_system or have_user
> stub_ss.add(files('hotplug-stubs.c'))
> stub_ss.add(files('sysbus.c'))
> endif
> +
> +if host_os == 'emscripten'
> + stub_ss.add(files('emscripten.c'))
> +endif
> ---
Actually what about checking the symbol presence in meson?
Something like (untested):
-- >8 --
diff --git a/meson.build b/meson.build
index b18c46d16a2..33185fdf315 100644
--- a/meson.build
+++ b/meson.build
@@ -2654,3 +2654,2 @@ config_host_data.set('CONFIG_TIMERFD',
cc.has_function('timerfd_create'))
config_host_data.set('CONFIG_GETLOADAVG', cc.has_function('getloadavg'))
-config_host_data.set('HAVE_COPY_FILE_RANGE',
cc.has_function('copy_file_range'))
config_host_data.set('HAVE_GETIFADDRS', cc.has_function('getifaddrs'))
@@ -2756,2 +2755,6 @@ config_host_data.set('HAVE_UTMPX',
+config_host_data.set('HAVE_COPY_FILE_RANGE', cc.links(gnu_source_prefix
+ '''
+ #include <unistd.h>
+ int main(void) { return copy_file_range(-1, NULL, -1, NULL, 0, 0); }'''))
config_host_data.set('CONFIG_EVENTFD', cc.links('''
---
Hi Philippe and Richard, thank you for the feedback.
> Actually what about checking the symbol presence in meson?
> Something like (untested):
>
> -- >8 --
> diff --git a/meson.build b/meson.build
> index b18c46d16a2..33185fdf315 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -2654,3 +2654,2 @@ config_host_data.set('CONFIG_TIMERFD',
> cc.has_function('timerfd_create'))
> config_host_data.set('CONFIG_GETLOADAVG', cc.has_function('getloadavg'))
> -config_host_data.set('HAVE_COPY_FILE_RANGE',
> cc.has_function('copy_file_range'))
> config_host_data.set('HAVE_GETIFADDRS', cc.has_function('getifaddrs'))
> @@ -2756,2 +2755,6 @@ config_host_data.set('HAVE_UTMPX',
>
> +config_host_data.set('HAVE_COPY_FILE_RANGE', cc.links(gnu_source_prefix
> + '''
> + #include <unistd.h>
> + int main(void) { return copy_file_range(-1, NULL, -1, NULL, 0, 0);
}'''))
> config_host_data.set('CONFIG_EVENTFD', cc.links('''
> ---
Emscripten doesn't provide copy_file_range implementation but it declares
this function in its headers. Meson correctly detects the missing
implementation and unsets HAVE_COPY_FILE_RANGE. However, the stub defined in
file-posix.c causes a type conflict with the declaration from Emscripten
during compilation:
> ../qemu/block/file-posix.c:2019:14: error: static declaration of
'copy_file_range' follows non-static declaration
> 2019 | static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
> | ^
> /emsdk/upstream/emscripten/cache/sysroot/include/unistd.h:207:9: note:
previous declaration is here
> 207 | ssize_t copy_file_range(int, off_t *, int, off_t *, size_t,
unsigned);
> | ^
> 1 error generated.
If introducing a new stub isn't preferable, we could update the existing
stub in file-posix.c to match the declaration used by Emscripten. The
manpage[1] also aligns with this signature.
[1] https://man7.org/linux/man-pages/man2/copy_file_range.2.html
On 17/4/25 11:32, Kohei Tokunaga wrote:
>
> Hi Philippe and Richard, thank you for the feedback.
>
> > Actually what about checking the symbol presence in meson?
> > Something like (untested):
> >
> > -- >8 --
> > diff --git a/meson.build b/meson.build
> > index b18c46d16a2..33185fdf315 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -2654,3 +2654,2 @@ config_host_data.set('CONFIG_TIMERFD',
> > cc.has_function('timerfd_create'))
> > config_host_data.set('CONFIG_GETLOADAVG',
> cc.has_function('getloadavg'))
> > -config_host_data.set('HAVE_COPY_FILE_RANGE',
> > cc.has_function('copy_file_range'))
> > config_host_data.set('HAVE_GETIFADDRS', cc.has_function('getifaddrs'))
> > @@ -2756,2 +2755,6 @@ config_host_data.set('HAVE_UTMPX',
> >
> > +config_host_data.set('HAVE_COPY_FILE_RANGE', cc.links(gnu_source_prefix
> > + '''
> > + #include <unistd.h>
> > + int main(void) { return copy_file_range(-1, NULL, -1, NULL, 0,
> 0); }'''))
> > config_host_data.set('CONFIG_EVENTFD', cc.links('''
> > ---
>
> Emscripten doesn't provide copy_file_range implementation but it declares
> this function in its headers. Meson correctly detects the missing
> implementation and unsets HAVE_COPY_FILE_RANGE. However, the stub defined in
> file-posix.c causes a type conflict with the declaration from Emscripten
> during compilation:
>
> > ../qemu/block/file-posix.c:2019:14: error: static declaration of
> 'copy_file_range' follows non-static declaration
> > 2019 | static off_t copy_file_range(int in_fd, off_t *in_off, int
> out_fd,
> > | ^
> > /emsdk/upstream/emscripten/cache/sysroot/include/unistd.h:207:9:
> note: previous declaration is here
> > 207 | ssize_t copy_file_range(int, off_t *, int, off_t *, size_t,
> unsigned);
> > | ^
> > 1 error generated.
>
> If introducing a new stub isn't preferable, we could update the existing
> stub in file-posix.c to match the declaration used by Emscripten. The
> manpage[1] also aligns with this signature.
You are correct we should use ssize_t instead of off_t.
If meson fails to link, it won't define HAVE_COPY_FILE_RANGE, so you
shouldn't get "static declaration of 'copy_file_range' follows
non-static declaration" right?
>
> [1] https://man7.org/linux/man-pages/man2/copy_file_range.2.html
> <https://man7.org/linux/man-pages/man2/copy_file_range.2.html>
>
Hi Philippe,
> If meson fails to link, it won't define HAVE_COPY_FILE_RANGE,
Yes, meson correctly detects the link failure when checking for
copy_file_range, as shown in meson-log.txt:
> wasm-ld: error: /tmp/emscripten_temp_oqvz296m/testfile_0.o: undefined
symbol: copy_file_range
and reflects this in the configure output:
> Checking for function "copy_file_range" : NO
> so you
> shouldn't get "static declaration of 'copy_file_range' follows
> non-static declaration" right?
To fix this error, I needed to update the stub implementation in
file-posix.c to exactly match the declaration in Emscripten's
headers. Specifically, I changed the return type from off_t to ssize_t and
removed the "static" qualifier. With this change, file-posix.c builds
correctly under Emscripten, and there is no need to add a new stub in
stubs/emscripten.c
The following is the patch updates file-posix.c to solve this error:
#ifndef HAVE_COPY_FILE_RANGE
-static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
- off_t *out_off, size_t len, unsigned int
flags)
+ssize_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
+ off_t *out_off, size_t len, unsigned int
flags)
{
#ifdef __NR_copy_file_range
return syscall(__NR_copy_file_range, in_fd, in_off, out_fd,
On 18/4/25 08:53, Kohei Tokunaga wrote:
> The following is the patch updates file-posix.c to solve this error:
>
> #ifndef HAVE_COPY_FILE_RANGE
> -static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
> - off_t *out_off, size_t len, unsigned int
> flags)
> +ssize_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
> + off_t *out_off, size_t len, unsigned int
> flags)
> {
> #ifdef __NR_copy_file_range
> return syscall(__NR_copy_file_range, in_fd, in_off, out_fd,
>
Yes, LGTM!
On 4/16/25 02:33, Philippe Mathieu-Daudé wrote:
> On 16/4/25 11:00, Philippe Mathieu-Daudé wrote:
>> On 16/4/25 10:14, Kohei Tokunaga wrote:
>>> emscripten exposes copy_file_range declaration but doesn't provide the
>>> implementation in the final link. Define the emscripten-specific stub
>>> function to avoid type conflict with the emscripten's header.
>>>
>>> Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
>>> ---
>>> block/file-posix.c | 6 ++++++
>>> stubs/emscripten.c | 13 +++++++++++++
>>> 2 files changed, 19 insertions(+)
>>> create mode 100644 stubs/emscripten.c
>>>
>>> diff --git a/block/file-posix.c b/block/file-posix.c
>>> index 56d1972d15..22e0ed5069 100644
>>> --- a/block/file-posix.c
>>> +++ b/block/file-posix.c
>>> @@ -110,6 +110,10 @@
>>> #include <sys/diskslice.h>
>>> #endif
>>> +#ifdef EMSCRIPTEN
>>> +#include <sys/ioctl.h>
>>> +#endif
>>> +
>>> /* OS X does not have O_DSYNC */
>>> #ifndef O_DSYNC
>>> #ifdef O_SYNC
>>> @@ -2010,6 +2014,7 @@ static int handle_aiocb_write_zeroes_unmap(void *opaque)
>>> return handle_aiocb_write_zeroes(aiocb);
>>> }
>>> +#ifndef EMSCRIPTEN
>>> #ifndef HAVE_COPY_FILE_RANGE
>>> static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
>>> off_t *out_off, size_t len, unsigned int flags)
>>> @@ -2023,6 +2028,7 @@ static off_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
>>> #endif
>>> }
>>> #endif
>>> +#endif
>>> /*
>>> * parse_zone - Fill a zone descriptor
>>> diff --git a/stubs/emscripten.c b/stubs/emscripten.c
>>> new file mode 100644
>>> index 0000000000..2157d6349b
>>> --- /dev/null
>>> +++ b/stubs/emscripten.c
>>> @@ -0,0 +1,13 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>>> +#include "qemu/osdep.h"
>>> +/*
>>> + * emscripten exposes copy_file_range declaration but doesn't provide the
>>> + * implementation in the final link. Define the stub here but avoid type
>>> + * conflict with the emscripten's header.
>>> + */
>>> +ssize_t copy_file_range(int in_fd, off_t *in_off, int out_fd,
>>> + off_t *out_off, size_t len, unsigned int flags)
>>> +{
>>> + errno = ENOSYS;
>>> + return -1;
>>> +}
>>
>> I'd include in this patch this hunk from patch 17:
>>
>> -- >8 --
>> diff --git a/stubs/meson.build b/stubs/meson.build
>> index 63392f5e78..4fd4d362f9 100644
>> --- a/stubs/meson.build
>> +++ b/stubs/meson.build
>> @@ -89,3 +89,7 @@ if have_system or have_user
>> stub_ss.add(files('hotplug-stubs.c'))
>> stub_ss.add(files('sysbus.c'))
>> endif
>> +
>> +if host_os == 'emscripten'
>> + stub_ss.add(files('emscripten.c'))
>> +endif
>> ---
>
> Actually what about checking the symbol presence in meson?
> Something like (untested):
>
> -- >8 --
> diff --git a/meson.build b/meson.build
> index b18c46d16a2..33185fdf315 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -2654,3 +2654,2 @@ config_host_data.set('CONFIG_TIMERFD',
> cc.has_function('timerfd_create'))
> config_host_data.set('CONFIG_GETLOADAVG', cc.has_function('getloadavg'))
> -config_host_data.set('HAVE_COPY_FILE_RANGE', cc.has_function('copy_file_range'))
> config_host_data.set('HAVE_GETIFADDRS', cc.has_function('getifaddrs'))
> @@ -2756,2 +2755,6 @@ config_host_data.set('HAVE_UTMPX',
>
> +config_host_data.set('HAVE_COPY_FILE_RANGE', cc.links(gnu_source_prefix + '''
> + #include <unistd.h>
> + int main(void) { return copy_file_range(-1, NULL, -1, NULL, 0, 0); }'''))
> config_host_data.set('CONFIG_EVENTFD', cc.links('''
> ---
Yes indeed. We should be making sure HAVE_COPY_FILE_RANGE is unset, not providing stubs.
r~
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