1 files changed, 57 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/lseek.c b/sysdeps/unix/sysv/linux/lseek.c
new file mode 100644
index 0000000000..49d11ab65a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/lseek.c
@@ -0,0 +1,57 @@
+/* Linux lseek implementation, 32 bits off_t.
+   Copyright (C) 2016-2018 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 <unistd.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sysdep.h>
+#include <errno.h>
+
+#ifndef __OFF_T_MATCHES_OFF64_T
+
+/* Test for overflows of structures where we ask the kernel to fill them
+   in with standard 64-bit syscalls but return them through APIs that
+   only expose the low 32 bits of some fields.  */
+
+static inline off_t lseek_overflow (loff_t res)
+{
+  off_t retval = (off_t) res;
+  if (retval == res)
+    return retval;
+
+  __set_errno (EOVERFLOW);
+  return (off_t) -1;
+}
+
+off_t
+__lseek (int fd, off_t offset, int whence)
+{
+# ifdef __NR__llseek
+  loff_t res;
+  int rc = INLINE_SYSCALL_CALL (_llseek, fd,
+				(long) (((uint64_t) (offset)) >> 32),
+				(long) offset, &res, whence);
+  return rc ?: lseek_overflow (res);
+# else
+  return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
+# endif
+}
+libc_hidden_def (__lseek)
+weak_alias (__lseek, lseek)
+strong_alias (__lseek, __libc_lseek)
+#endif /* __OFF_T_MATCHES_OFF64_T  */