hurd: Implement close_range and closefrom

The close_range () function implements the same API as the Linux and
FreeBSD syscalls. It operates atomically and reliably. The specified
upper bound is clamped to the actual size of the file descriptor table;
it is expected that the most common use case is with last = UINT_MAX.

Like in the Linux syscall, it is also possible to pass the
CLOSE_RANGE_CLOEXEC flag to mark the file descriptors in the range
cloexec instead of acually closing them.

Also, add a Hurd version of the closefrom () function. Since unlike on
Linux, close_range () cannot fail due to being unuspported by the
running kernel, a fallback implementation is never necessary.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20211106153524.82700-1-bugaevc@gmail.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/Versions b/sysdeps/mach/hurd/Versions
index 89dabd0485..d75e674bb6 100644
--- a/sysdeps/mach/hurd/Versions
+++ b/sysdeps/mach/hurd/Versions
@@ -10,6 +10,9 @@ libc {
   GLIBC_2.32 {
     mremap;
   }
+  GLIBC_2.35 {
+    close_range;
+  }
   GLIBC_PRIVATE {
     # Functions shared with the dynamic linker
     __access; __access_noerrno; __libc_read; __libc_write; __libc_lseek64;