This workaround is adapted from Coreutils.
* lib/copy-file-range.c [__linux__ && HAVE_COPY_FILE_RANGE]:
Include .
(copy_file_range): Use a stub to replace the copy_file_range of
Linux kernel versions 4.5 through 5.2.
* lib/unistd.in.h (copy_file_range):
* m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS):
* modules/copy-file-range (configure.ac):
* modules/unistd (unistd.h):
Support replacement of copy_file_range.
* m4/copy-file-range.m4 (gl_FUNC_COPY_FILE_RANGE):
Define HAVE_COPY_FILE_RANGE if the system has copy_file_range,
and on Linux check whether the system’s is known to work.
---
ChangeLog| 17
doc/glibc-functions/copy_file_range.texi | 5
lib/copy-file-range.c| 34
lib/unistd.in.h | 16 ++-
m4/copy-file-range.m4| 25 -
m4/unistd_h.m4 | 1 +
modules/copy-file-range | 4 ++-
modules/unistd | 1 +
8 files changed, 100 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 93fe05770b..a900fec78d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2022-01-14 Paul Eggert
+
+ copy-file-range: work around Linux kernel bug
+ This workaround is adapted from Coreutils.
+ * lib/copy-file-range.c [__linux__ && HAVE_COPY_FILE_RANGE]:
+ Include .
+ (copy_file_range): Use a stub to replace the copy_file_range of
+ Linux kernel versions 4.5 through 5.2.
+ * lib/unistd.in.h (copy_file_range):
+ * m4/unistd_h.m4 (gl_UNISTD_H_DEFAULTS):
+ * modules/copy-file-range (configure.ac):
+ * modules/unistd (unistd.h):
+ Support replacement of copy_file_range.
+ * m4/copy-file-range.m4 (gl_FUNC_COPY_FILE_RANGE):
+ Define HAVE_COPY_FILE_RANGE if the system has copy_file_range,
+ and on Linux check whether the system’s is known to work.
+
2022-01-14 Bruno Haible
Avoid error "conditional LIBUNISTRING_COMPILE_... was never defined"
diff --git a/doc/glibc-functions/copy_file_range.texi
b/doc/glibc-functions/copy_file_range.texi
index baac6e1302..f10271c157 100644
--- a/doc/glibc-functions/copy_file_range.texi
+++ b/doc/glibc-functions/copy_file_range.texi
@@ -24,6 +24,11 @@ This function exists only on Linux and FreeBSD and is
therefore
missing on many non-glibc platforms:
glibc 2.26, macOS 11.1, FreeBSD 12.0, NetBSD 9.0, OpenBSD 6.7, Minix 3.1.8,
AIX 7.1, HP-UX 11.31, IRIX 6.5, Solaris 11.4, Cygwin 2.9, mingw, MSVC 14,
Android 9.0.
But the replacement function is only a stub: It always fails with error ENOSYS.
+
+@item
+This function has many problems on Linux kernel versions before 5.3.
+On these kernel versions, the replacement function always fails with
+error ENOSYS.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/lib/copy-file-range.c b/lib/copy-file-range.c
index 96f1ec7c5e..1ec7f4de67 100644
--- a/lib/copy-file-range.c
+++ b/lib/copy-file-range.c
@@ -20,11 +20,45 @@
#include
+#if defined __linux__ && HAVE_COPY_FILE_RANGE
+# include
+#endif
+
ssize_t
copy_file_range (int infd, off_t *pinoff,
int outfd, off_t *poutoff,
size_t length, unsigned int flags)
{
+#undef copy_file_range
+
+#if defined __linux__ && HAVE_COPY_FILE_RANGE
+ /* The implementation of copy_file_range (which first appeared in
+ Linux kernel release 4.5) had many issues before release 5.3
+ , so fail with ENOSYS for Linux
+ kernels 5.2 and earlier.
+
+ This workaround, and the configure-time check for Linux, can be
+ removed when such kernels (released March 2016 through September
+ 2019) are no longer a consideration. As of January 2021, the
+ furthest-future planned kernel EOL is December 2024 for kernel
+ release 4.19. */
+
+static signed char ok;
+
+if (! ok)
+ {
+struct utsname name;
+uname (&name);
+char *p = name.release;
+ok = ((p[1] != '.' || '5' < p[0]
+ || (p[0] == '5' && (p[3] != '.' || '2' < p[2])))
+ ? 1 : -1);
+ }
+
+if (0 < ok)
+ return copy_file_range (infd, pinoff, outfd, poutoff, length, flags);
+#endif
+
/* There is little need to emulate copy_file_range with read+write,
since programs that use copy_file_range must fall back on
read+write anyway. */
diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index 3386f0b0f7..57df09ecdf 100644
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -415,16 +415,30 @@ _GL_CXXALIASWARN (close);
#if @GNULIB_COPY_FILE_RANGE@
-# if !@HAVE_COPY_FILE_RANGE@
+# if @REPLACE_COPY_FILE_RANGE@
+# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+# undef copy_file_range
+# define copy_file_range rpl_copy_file_range
+# endif
+_GL_FUNCDECL_RPL (copy_file_range, ssize_t, (int ifd, off_t *ipos,
+
