Add the statx function

8 files changed, 371 insertions, 1 deletions

diff --git a/io/Makefile b/io/Makefile
index 4a0d8fe..f5b1b61 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -31,7 +31,7 @@ routines :=								\
 	utime								\
 	mkfifo mkfifoat							\
 	stat fstat lstat stat64 fstat64 lstat64 fstatat fstatat64	\
-	xstat fxstat lxstat xstat64 fxstat64 lxstat64			\
+	xstat fxstat lxstat xstat64 fxstat64 lxstat64 statx		\
 	mknod mknodat xmknod xmknodat					\
 	fxstatat fxstatat64						\
 	statfs fstatfs statfs64 fstatfs64				\
@@ -78,6 +78,9 @@ tests		:= test-utime test-stat test-stat2 test-lfs tst-getcwd \
 tests-static += tst-copy_file_range-compat
 tests-internal += tst-copy_file_range-compat
 
+# Likewise for statx, but we do not need static linking here.
+tests-internal += tst-statx
+
 ifeq ($(run-built-tests),yes)
 tests-special += $(objpfx)ftwtest.out
 endif
diff --git a/io/Versions b/io/Versions
index 98037fb..f7e5dbe 100644
--- a/io/Versions
+++ b/io/Versions
@@ -130,6 +130,7 @@ libc {
   }
   GLIBC_2.28 {
     fcntl64;
+    statx;
   }
   GLIBC_PRIVATE {
     __libc_fcntl64;
diff --git a/io/bits/statx.h b/io/bits/statx.h
new file mode 100644
index 0000000..e31254e
--- /dev/null
+++ b/io/bits/statx.h
@@ -0,0 +1,91 @@
+/* statx-related definitions and declarations.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This interface is based on <linux/stat.h> in Linux.  */
+
+#ifndef _SYS_STAT_H
+# error Never include <bits/stat.x.h> directly, include <sys/stat.h> instead.
+#endif
+
+struct statx_timestamp
+{
+  __int64_t tv_sec;
+  __uint32_t tv_nsec;
+  __int32_t __statx_timestamp_pad1[1];
+};
+
+/* Warning: The kernel may add additional fields to this struct in the
+   future.  Only use this struct for calling the statx function, not
+   for storing data.  (Expansion will be controlled by the mask
+   argument of the statx function.)  */
+struct statx
+{
+  __uint32_t stx_mask;
+  __uint32_t stx_blksize;
+  __uint64_t stx_attributes;
+  __uint32_t stx_nlink;
+  __uint32_t stx_uid;
+  __uint32_t stx_gid;
+  __uint16_t stx_mode;
+  __uint16_t __statx_pad1[1];
+  __uint64_t stx_ino;
+  __uint64_t stx_size;
+  __uint64_t stx_blocks;
+  __uint64_t stx_attributes_mask;
+  struct statx_timestamp stx_atime;
+  struct statx_timestamp stx_btime;
+  struct statx_timestamp stx_ctime;
+  struct statx_timestamp stx_mtime;
+  __uint32_t stx_rdev_major;
+  __uint32_t stx_rdev_minor;
+  __uint32_t stx_dev_major;
+  __uint32_t stx_dev_minor;
+  __uint64_t __statx_pad2[14];
+};
+
+#define STATX_TYPE 0x0001U
+#define STATX_MODE 0x0002U
+#define STATX_NLINK 0x0004U
+#define STATX_UID 0x0008U
+#define STATX_GID 0x0010U
+#define STATX_ATIME 0x0020U
+#define STATX_MTIME 0x0040U
+#define STATX_CTIME 0x0080U
+#define STATX_INO 0x0100U
+#define STATX_SIZE 0x0200U
+#define STATX_BLOCKS 0x0400U
+#define STATX_BASIC_STATS 0x07ffU
+#define STATX_ALL 0x0fffU
+#define STATX_BTIME 0x0800U
+#define STATX__RESERVED 0x80000000U
+
+#define STATX_ATTR_COMPRESSED 0x0004
+#define STATX_ATTR_IMMUTABLE 0x0010
+#define STATX_ATTR_APPEND 0x0020
+#define STATX_ATTR_NODUMP 0x0040
+#define STATX_ATTR_ENCRYPTED 0x0800
+#define STATX_ATTR_AUTOMOUNT 0x1000
+
+__BEGIN_DECLS
+
+/* Fill *BUF with information about PATH in DIRFD.  */
+int statx (int __dirfd, const char *__restrict __path, int __flags,
+           unsigned int __mask, struct statx *__restrict __buf)
+  __THROW __nonnull ((2, 5));
+
+__END_DECLS
diff --git a/io/fcntl.h b/io/fcntl.h
index 3afc620..6b0e9fa 100644
--- a/io/fcntl.h
+++ b/io/fcntl.h
@@ -157,6 +157,10 @@ typedef __pid_t pid_t;
 #  define AT_NO_AUTOMOUNT	0x800	/* Suppress terminal automount
 					   traversal.  */
 #  define AT_EMPTY_PATH		0x1000	/* Allow empty relative pathname.  */
+#  define AT_STATX_SYNC_TYPE	0x6000
+#  define AT_STATX_SYNC_AS_STAT	0x0000
+#  define AT_STATX_FORCE_SYNC	0x2000
+#  define AT_STATX_DONT_SYNC	0x4000
 # endif
 # define AT_EACCESS		0x200	/* Test access permitted for
 					   effective IDs, not real IDs.  */
diff --git a/io/statx.c b/io/statx.c
new file mode 100644
index 0000000..0b90cd0
--- /dev/null
+++ b/io/statx.c
@@ -0,0 +1,29 @@
+/* Generic statx implementation.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sys/stat.h>
+
+#include "statx_generic.c"
+
+int
+statx (int fd, const char *path, int flags,
+       unsigned int mask, struct statx *buf)
+{
+  return statx_generic (fd, path, flags, mask, buf);
+}
diff --git a/io/statx_generic.c b/io/statx_generic.c
new file mode 100644
index 0000000..df327f8
--- /dev/null
+++ b/io/statx_generic.c
@@ -0,0 +1,81 @@
+/* Generic implementation of statx based on fstatat64.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+
+static inline struct statx_timestamp
+statx_convert_timestamp (struct timespec tv)
+{
+  return (struct statx_timestamp) { tv.tv_sec, tv.tv_nsec };
+}
+
+/* Approximate emulation of statx.  This will always fill in
+   POSIX-mandated attributes even if the underlying file system does
+   not actually support it (for example, GID and UID on file systems
+   without UNIX-style permissions).  */
+static __attribute__ ((unused)) int
+statx_generic (int fd, const char *path, int flags,
+               unsigned int mask, struct statx *buf)
+{
+  /* Flags which need to be cleared before passing them to
+     fstatat64.  */
+  static const int clear_flags = AT_STATX_SYNC_AS_STAT;
+
+    /* Flags supported by our emulation.  */
+  static const int supported_flags
+    = AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW | clear_flags;
+
+  if (__glibc_unlikely ((flags & ~supported_flags) != 0))
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  struct stat64 st;
+  int ret = __fstatat64 (fd, path, &st, flags & ~clear_flags);
+  if (ret != 0)
+    return ret;
+
+  /* The interface is defined in such a way that unused (padding)
+     fields have to be cleared.  STATX_BASIC_STATS corresponds to the
+     data which is available via fstatat64.  */
+  *buf = (struct statx)
+    {
+      .stx_mask = STATX_BASIC_STATS,
+      .stx_blksize = st.st_blksize,
+      .stx_nlink = st.st_nlink,
+      .stx_uid = st.st_uid,
+      .stx_gid = st.st_gid,
+      .stx_mode = st.st_mode,
+      .stx_ino = st.st_ino,
+      .stx_size = st.st_size,
+      .stx_blocks = st.st_blocks,
+      .stx_atime = statx_convert_timestamp (st.st_atim),
+      .stx_ctime = statx_convert_timestamp (st.st_ctim),
+      .stx_mtime = statx_convert_timestamp (st.st_mtim),
+      .stx_rdev_major = major (st.st_rdev),
+      .stx_rdev_minor = minor (st.st_rdev),
+      .stx_dev_major = major (st.st_dev),
+      .stx_dev_minor = minor (st.st_dev),
+    };
+
+  return 0;
+}
diff --git a/io/sys/stat.h b/io/sys/stat.h
index 90c403c..762c853 100644
--- a/io/sys/stat.h
+++ b/io/sys/stat.h
@@ -442,6 +442,10 @@ extern int __xmknodat (int __ver, int __fd, const char *__path,
 		       __mode_t __mode, __dev_t *__dev)
      __THROW __nonnull ((3, 5));
 
+#ifdef __USE_GNU
+# include <bits/statx.h>
+#endif
+
 #ifdef __USE_EXTERN_INLINES
 /* Inlined versions of the real stat and mknod functions.  */
 
diff --git a/io/tst-statx.c b/io/tst-statx.c
new file mode 100644
index 0000000..61bf31d
--- /dev/null
+++ b/io/tst-statx.c
@@ -0,0 +1,157 @@
+/* Basic test of statx system call.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/temp_file.h>
+#include <support/xunistd.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/sysmacros.h>
+#include <unistd.h>
+
+/* Ensure that the types have the kernel-expected layout.  */
+_Static_assert (sizeof (struct statx_timestamp) == 16, "statx_timestamp size");
+_Static_assert (sizeof (struct statx) == 256, "statx size");
+_Static_assert (offsetof (struct statx, stx_nlink) == 16, "statx nlink");
+_Static_assert (offsetof (struct statx, stx_ino) == 32, "statx ino");
+_Static_assert (offsetof (struct statx, stx_atime) == 64, "statx atime");
+_Static_assert (offsetof (struct statx, stx_rdev_major) == 128, "statx rdev");
+_Static_assert (offsetof (struct statx, __statx_pad2) == 144, "statx pad2");
+
+#include "statx_generic.c"
+
+typedef int (*statx_function) (int, const char *, int, unsigned int,
+                               struct statx *);
+
+/* Return true if we have a real implementation of statx.  */
+static bool
+kernel_supports_statx (void)
+{
+#ifdef __NR_statx
+  struct statx buf;
+  return syscall (__NR_statx, 0, "", AT_EMPTY_PATH, 0, &buf) == 0
+    || errno != ENOSYS;
+#else
+  return false;
+#endif
+}
+
+/* Tests which apply to both implementations.  */
+static void
+both_implementations_tests (statx_function impl, const char *path, int fd)
+{
+  uint64_t ino;
+  {
+    struct statx buf = { 0, };
+    TEST_COMPARE (statx (fd, "", AT_EMPTY_PATH, STATX_BASIC_STATS, &buf), 0);
+    TEST_COMPARE (buf.stx_size, 3);
+    ino = buf.stx_ino;
+  }
+  {
+    struct statx buf = { 0, };
+    TEST_COMPARE (statx (AT_FDCWD, path, 0, STATX_BASIC_STATS, &buf), 0);
+    TEST_COMPARE (buf.stx_size, 3);
+    TEST_COMPARE (buf.stx_ino, ino);
+  }
+  {
+    struct statx stx = { 0, };
+    TEST_COMPARE (statx (fd, "", AT_EMPTY_PATH, STATX_BASIC_STATS, &stx), 0);
+    struct stat64 st;
+    xfstat (fd, &st);
+    TEST_COMPARE (stx.stx_mode, st.st_mode);
+    TEST_COMPARE (stx.stx_dev_major, major (st.st_dev));
+    TEST_COMPARE (stx.stx_dev_minor, minor (st.st_dev));
+  }
+  {
+    struct statx stx = { 0, };
+    TEST_COMPARE (statx (AT_FDCWD, "/dev/null", 0, STATX_BASIC_STATS, &stx),
+                  0);
+    struct stat64 st;
+    xstat ("/dev/null", &st);
+    TEST_COMPARE (stx.stx_mode, st.st_mode);
+    TEST_COMPARE (stx.stx_dev_major, major (st.st_dev));
+    TEST_COMPARE (stx.stx_dev_minor, minor (st.st_dev));
+    TEST_COMPARE (stx.stx_rdev_major, major (st.st_rdev));
+    TEST_COMPARE (stx.stx_rdev_minor, minor (st.st_rdev));
+  }
+}
+
+/* Tests which apply only to the non-kernel (generic)
+   implementation.  */
+static void
+non_kernel_tests (statx_function impl, int fd)
+{
+  /* The non-kernel implementation must always fail for explicit sync
+     flags.  */
+  struct statx buf;
+  errno = 0;
+  TEST_COMPARE (impl (fd, "", AT_EMPTY_PATH | AT_STATX_FORCE_SYNC,
+                      STATX_BASIC_STATS, &buf), -1);
+  TEST_COMPARE (errno, EINVAL);
+  errno = 0;
+  TEST_COMPARE (impl (fd, "", AT_EMPTY_PATH | AT_STATX_DONT_SYNC,
+                      STATX_BASIC_STATS, &buf), -1);
+  TEST_COMPARE (errno, EINVAL);
+}
+
+static int
+do_test (void)
+{
+  char *path;
+  int fd = create_temp_file ("tst-statx-", &path);
+  TEST_VERIFY_EXIT (fd >= 0);
+  support_write_file_string (path, "abc");
+
+  both_implementations_tests (&statx, path, fd);
+  both_implementations_tests (&statx_generic, path, fd);
+
+  if (kernel_supports_statx ())
+    {
+      puts ("info: kernel supports statx");
+      struct statx buf;
+      buf.stx_size = 0;
+      TEST_COMPARE (statx (fd, "", AT_EMPTY_PATH | AT_STATX_FORCE_SYNC,
+                           STATX_BASIC_STATS, &buf),
+                    0);
+      TEST_COMPARE (buf.stx_size, 3);
+      buf.stx_size = 0;
+      TEST_COMPARE (statx (fd, "", AT_EMPTY_PATH | AT_STATX_DONT_SYNC,
+                           STATX_BASIC_STATS, &buf),
+                    0);
+      TEST_COMPARE (buf.stx_size, 3);
+    }
+  else
+    {
+      puts ("info: kernel does not support statx");
+      non_kernel_tests (&statx, fd);
+    }
+  non_kernel_tests (&statx_generic, fd);
+
+  xclose (fd);
+  free (path);
+
+  return 0;
+}
+
+#include <support/test-driver.c>