Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
---
 block/file-posix.c        | 18 ++++++++++++++++++
 include/qemu/cacheflush.h |  3 ++-
 os-posix.c                |  5 +++++
 util/cacheflush.c         |  3 ++-
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 56d1972d15..69f54505bd 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
@@ -2011,6 +2015,19 @@ static int handle_aiocb_write_zeroes_unmap(void *opaque)
 }
 
 #ifndef HAVE_COPY_FILE_RANGE
+#ifdef EMSCRIPTEN
+/*
+ * 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;
+}
+#else
 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 +2040,7 @@ 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/include/qemu/cacheflush.h b/include/qemu/cacheflush.h
index ae20bcda73..84969801e3 100644
--- a/include/qemu/cacheflush.h
+++ b/include/qemu/cacheflush.h
@@ -19,7 +19,8 @@
  * mappings of the same physical page(s).
  */
 
-#if defined(__i386__) || defined(__x86_64__) || defined(__s390__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__s390__) \
+    || defined(EMSCRIPTEN)
 
 static inline void flush_idcache_range(uintptr_t rx, uintptr_t rw, size_t len)
 {
diff --git a/os-posix.c b/os-posix.c
index 52925c23d3..9a7099e279 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -148,11 +148,16 @@ static void change_process_uid(void)
             exit(1);
         }
         if (user_pwd) {
+#ifdef EMSCRIPTEN
+            error_report("initgroups unsupported");
+            exit(1);
+#else
             if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) {
                 error_report("Failed to initgroups(\"%s\", %d)",
                         user_pwd->pw_name, user_pwd->pw_gid);
                 exit(1);
             }
+#endif
         } else {
             if (setgroups(1, &user_gid) < 0) {
                 error_report("Failed to setgroups(1, [%d])",
diff --git a/util/cacheflush.c b/util/cacheflush.c
index 1d12899a39..e5aa256cd8 100644
--- a/util/cacheflush.c
+++ b/util/cacheflush.c
@@ -225,7 +225,8 @@ static void __attribute__((constructor)) init_cache_info(void)
  * Architecture (+ OS) specific cache flushing mechanisms.
  */
 
-#if defined(__i386__) || defined(__x86_64__) || defined(__s390__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__s390__) || \
+    defined(EMSCRIPTEN)
 
 /* Caches are coherent and do not require flushing; symbol inline. */
 
-- 
2.25.1

On 4/7/25 16:45, Kohei Tokunaga wrote:
> +#ifdef EMSCRIPTEN
> +/*
> + * 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;
> +}

Please add a file stubs/emscripten.c with this function, and add it to 
the build in stubs/meson.build.

> +#ifdef EMSCRIPTEN
> +            error_report("initgroups unsupported");
> +            exit(1);

I think it's best to add a new function os-wasm.c in addition to 
os-posix.c and os-win32.c, and disable all the functionality of 
-run-with and -daemonize in vl.c via

-#if defined(CONFIG_POSIX)
+#if defined(CONFIG_POSIX) && !defined(EMSCRIPTEN)

(there are a couple occurrences).

Thanks,

Paolo

Hi Paolo,

> > +#ifdef EMSCRIPTEN
> > +/*
> > + * 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;
> > +}
>
> Please add a file stubs/emscripten.c with this function, and add it to
> the build in stubs/meson.build.
>
> > +#ifdef EMSCRIPTEN
> > +            error_report("initgroups unsupported");
> > +            exit(1);
>
> I think it's best to add a new function os-wasm.c in addition to
> os-posix.c and os-win32.c, and disable all the functionality of
> -run-with and -daemonize in vl.c via
>
> -#if defined(CONFIG_POSIX)
> +#if defined(CONFIG_POSIX) && !defined(EMSCRIPTEN)
>
> (there are a couple occurrences).

Sure, I'll apply these reorganization in the next version of the series.