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lib/fs: fix issue when {name,open}_to_handle_at() is not implemented 

With commit d5e6ee0dac the usage of functions name_to_handle_at() and
open_by_handle_at() are introduced. But these function are not available
e.g. in uclibc-ng < 1.0.35. To have a backward compatibility check for the
availability in the configure script and in case of absence do a direct
syscall.

Fixes: d5e6ee0dac ("ss: introduce cgroup2 cache and helper functions")
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Petr Vorel <petr.vorel@gmail.com>
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
Reviewed-by: Petr Vorel <petr.vorel@gmail.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
This commit is contained in:
Heiko Thiery 2021-05-08 08:49:26 +02:00 committed by David Ahern
parent 62c88ed940
commit c5b72cc56b
2 changed files with 53 additions and 0 deletions
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28
configure vendored
View File

@ -202,6 +202,31 @@ EOF
rm -f $TMPDIR/setnstest.c $TMPDIR/setnstest
}
check_name_to_handle_at()
{
cat >$TMPDIR/name_to_handle_at_test.c <<EOF
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
int main(int argc, char **argv)
{
struct file_handle *fhp;
int mount_id, flags, dirfd;
char *pathname;
name_to_handle_at(dirfd, pathname, fhp, &mount_id, flags);
return 0;
}
EOF
if $CC -I$INCLUDE -o $TMPDIR/name_to_handle_at_test $TMPDIR/name_to_handle_at_test.c >/dev/null 2>&1; then
echo "yes"
echo "CFLAGS += -DHAVE_HANDLE_AT" >>$CONFIG
else
echo "no"
fi
rm -f $TMPDIR/name_to_handle_at_test.c $TMPDIR/name_to_handle_at_test
}
check_ipset()
{
cat >$TMPDIR/ipsettest.c <<EOF
@ -492,6 +517,9 @@ fi
echo -n "libc has setns: "
check_setns
echo -n "libc has name_to_handle_at: "
check_name_to_handle_at
echo -n "SELinux support: "
check_selinux

25
lib/fs.c
View File

@ -25,11 +25,36 @@
#include "utils.h"
#ifndef HAVE_HANDLE_AT
# include <sys/syscall.h>
#endif
#define CGROUP2_FS_NAME "cgroup2"
/* if not already mounted cgroup2 is mounted here for iproute2's use */
#define MNT_CGRP2_PATH "/var/run/cgroup2"
#ifndef HAVE_HANDLE_AT
struct file_handle {
unsigned handle_bytes;
int handle_type;
unsigned char f_handle[];
};
static int name_to_handle_at(int dirfd, const char *pathname,
struct file_handle *handle, int *mount_id, int flags)
{
return syscall(__NR_name_to_handle_at, dirfd, pathname, handle,
mount_id, flags);
}
static int open_by_handle_at(int mount_fd, struct file_handle *handle, int flags)
{
return syscall(__NR_open_by_handle_at, mount_fd, handle, flags);
}
#endif
/* return mount path of first occurrence of given fstype */
static char *find_fs_mount(const char *fs_to_find)
{