linux: Implement mremap in C

Variadic function calls in syscalls.list does not work for all ABIs
(for instance where the argument are passed on the stack instead of
registers) and might have underlying issues depending of the variadic
type (for instance if a 64-bit argument is used).

Checked on x86_64-linux-gnu.

1 files changed, 41 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/mremap.c b/sysdeps/unix/sysv/linux/mremap.c
new file mode 100644
index 0000000..32e95db
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/mremap.c
@@ -0,0 +1,41 @@
+/* Remap a virtual memory address.  Linux specific syscall.
+   Copyright (C) 2021 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sys/mman.h>
+#include <sysdep.h>
+#include <stdarg.h>
+#include <stddef.h>
+
+void *
+__mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
+{
+  va_list va;
+  void *new_addr = NULL;
+
+  if (flags & MREMAP_FIXED)
+    {
+      va_start (va, flags);
+      new_addr = va_arg (va, void *);
+      va_end (va);
+    }
+
+  return (void *) INLINE_SYSCALL_CALL (mremap, addr, old_len, new_len, flags,
+				       new_addr);
+}
+libc_hidden_def (__mremap)
+weak_alias (__mremap, mremap)