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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-11-08 10:20:23 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-11-24 09:09:37 -0300
commit456b3c08b6fe78938af5d12b6869dc8c704696d6 (patch)
treebea5ff2432a7f589afccc126efb5ac8ab3b2c2b9 /include
parente186fc5a31e46f2cbf5ea1a75223b4412907f3d8 (diff)
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io: Refactor close_range and closefrom
Now that Hurd implementis both close_range and closefrom (f2c996597d),
we can make close_range() a base ABI, and make the default closefrom()
implementation on top of close_range().

The generic closefrom() implementation based on __getdtablesize() is
moved to generic close_range().  On Linux it will be overriden by
the auto-generation syscall while on Hurd it will be a system specific
implementation.

The closefrom() now calls close_range() and __closefrom_fallback().
Since on Hurd close_range() does not fail, __closefrom_fallback() is an
empty static inline function set by__ASSUME_CLOSE_RANGE.

The __ASSUME_CLOSE_RANGE also allows optimize Linux
__closefrom_fallback() implementation when --enable-kernel=5.9 or
higher is used.

Finally the Linux specific tst-close_range.c is moved to io and
enabled as default.  The Linuxism and CLOSE_RANGE_UNSHARE are
guarded so it can be built for Hurd (I have not actually test it).

Checked on x86_64-linux-gnu, i686-linux-gnu, and with a i686-gnu
build.
Diffstat (limited to 'include')
-rw-r--r--include/unistd.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/unistd.h b/include/unistd.h
index 7849562c42..2bcdd494e1 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -3,6 +3,9 @@
 
 # ifndef _ISOMAC
 
+#  include <stdbool.h>
+#  include <kernel-features.h>
+
 libc_hidden_proto (_exit, __noreturn__)
 #  ifndef NO_RTLD_HIDDEN
 rtld_hidden_proto (_exit, __noreturn__)
@@ -158,7 +161,14 @@ extern int __brk (void *__addr) attribute_hidden;
 extern int __close (int __fd);
 libc_hidden_proto (__close)
 extern int __libc_close (int __fd);
+#  if __ASSUME_CLOSE_RANGE
+static inline _Bool __closefrom_fallback (int __lowfd, _Bool dirfd_fallback)
+{
+  return false;
+}
+#  else
 extern _Bool __closefrom_fallback (int __lowfd, _Bool) attribute_hidden;
+#  endif
 extern ssize_t __read (int __fd, void *__buf, size_t __nbytes);
 libc_hidden_proto (__read)
 extern ssize_t __write (int __fd, const void *__buf, size_t __n);