io: Fix record locking contants on 32 bit arch with 64 bit default time_t (BZ#30477)

For architecture with default 64 bit time_t support, the kernel
does not provide LFS and non-LFS values for F_GETLK, F_GETLK, and
F_GETLK (the default value used for 64 bit architecture are used).

This is might be considered an ABI break, but the currenct exported
values is bogus anyway.

The POSIX lockf is not affected since it is aliased to lockf64,
which already uses the LFS values.

Checked on i686-linux-gnu and the new tests on a riscv32.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/io/tst-fcntl-lock.c b/io/tst-fcntl-lock.c
new file mode 100644
index 0000000000..357c4b7b56
--- /dev/null
+++ b/io/tst-fcntl-lock.c
@@ -0,0 +1,97 @@
+/* Test for advisory record locking.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; either version 2
+   of the License, or (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+
+/* This is essentially the POSIX lockf.  */
+
+static int
+fcntl_lockf (int fd, int cmd, off_t len)
+{
+  struct flock fl = {
+    .l_type = F_WRLCK,
+    .l_whence = SEEK_CUR,
+    .l_len = len
+  };
+
+  switch (cmd)
+    {
+    case F_TEST:
+      fl.l_type = F_RDLCK;
+      if (fcntl (fd, F_GETLK, &fl) < 0)
+	return -1;
+      if (fl.l_type == F_UNLCK || fl.l_pid == getpid ())
+	return 0;
+      errno = EACCES;
+      return -1;
+
+    case F_ULOCK:
+      fl.l_type = F_UNLCK;
+      return fcntl (fd, F_SETLK, &fl);
+
+    case F_LOCK:
+      return fcntl (fd, F_SETLKW, &fl);
+
+    case F_TLOCK:
+      return fcntl (fd, F_SETLK, &fl);
+    }
+
+  errno = EINVAL;
+  return -1;
+}
+
+static int
+fcntl64_lockf (int fd, int cmd, off64_t len64)
+  {
+  struct flock64 fl64 = {
+    .l_type = F_WRLCK,
+    .l_whence = SEEK_CUR,
+    .l_len = len64
+  };
+
+  switch (cmd)
+    {
+    case F_TEST:
+      fl64.l_type = F_RDLCK;
+      if (fcntl64 (fd, F_GETLK64, &fl64) < 0)
+	return -1;
+      if (fl64.l_type == F_UNLCK || fl64.l_pid == getpid ())
+	return 0;
+      errno = EACCES;
+      return -1;
+
+    case F_ULOCK:
+      fl64.l_type = F_UNLCK;
+      return fcntl64 (fd, F_SETLK64, &fl64);
+
+    case F_LOCK:
+      return fcntl64 (fd, F_SETLKW64, &fl64);
+
+    case F_TLOCK:
+      return fcntl64 (fd, F_SETLK64, &fl64);
+    }
+
+  errno = EINVAL;
+  return -1;
+}
+
+#define TST_LOCKFD  "tst-fcntl-lock."
+#define LOCKF       fcntl_lockf
+#define LOCKF64     fcntl64_lockf
+#include "tst-lockf.c"