[2/2] linux: add test for mremap w/ MREMAP_DONTUNMAP but w/o MREMAP_FIXED
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Commit Message
It should be tested since it's different code path, like the Linux
selftests did.
---
sysdeps/unix/sysv/linux/Makefile | 1 +
sysdeps/unix/sysv/linux/tst-linux-mremap2.c | 54 +++++++++++++++++++++++++++++
2 files changed, 55 insertions(+)
Comments
On 07/02/25 17:17, Celeste Liu wrote:
> It should be tested since it's different code path, like the Linux
> selftests did.
The test looks ok, although the point of the tst-linux-mremap1.c is to
check if the argument handling in the mremap implementation work
correctly [1]. This test seems to exercise the same path w.r.t to libc
wrapper.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=31968
> ---
> sysdeps/unix/sysv/linux/Makefile | 1 +
> sysdeps/unix/sysv/linux/tst-linux-mremap2.c | 54 +++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+)
>
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 395d2d65938d33de6747264a63b73915003281e6..fc10611cf979971d83f55dde4bc43771886ac8df 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -209,6 +209,7 @@ tests += \
> tst-gettid \
> tst-gettid-kill \
> tst-linux-mremap1 \
> + tst-linux-mremap2 \
> tst-memfd_create \
> tst-misalign-clone \
> tst-mlock2 \
> diff --git a/sysdeps/unix/sysv/linux/tst-linux-mremap2.c b/sysdeps/unix/sysv/linux/tst-linux-mremap2.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..be4e59223db840add8596ed30b0dcd91c248b96f
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-linux-mremap2.c
> @@ -0,0 +1,54 @@
> +/* Test mremap with MREMAP_DONTUNMAP.
> + Copyright (C) 2025 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 <errno.h>
> +#include <sys/mman.h>
> +#include <support/xstdlib.h>
> +#include <support/xunistd.h>
> +#include <support/check.h>
> +#include <support/test-driver.h>
> +#include <mremap-failure.h>
> +
> +static int
> +do_test (void)
> +{
> + size_t old_size = getpagesize ();
> + size_t new_size = old_size;
> + char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANONYMOUS, -1);
> + old_addr[0] = 1;
> + old_addr[old_size - 1] = 2;
> +
> + /* Test MREMAP_DONTUNMAP w/o MREMAP_FIXED. Old address is still available. */
> + char *new_addr = mremap (old_addr, old_size, new_size,
> + MREMAP_DONTUNMAP | MREMAP_MAYMOVE, NULL);
> + if (new_addr == MAP_FAILED)
> + return mremap_failure_exit (errno);
> + /* Old range should be zero-filled. */
> + TEST_VERIFY_EXIT (old_addr[0] == 0);
> + TEST_VERIFY_EXIT (old_addr[old_size - 1] == 0);
> + /* New range should have the same bytes as the old one. */
> + TEST_VERIFY_EXIT (new_addr[0] == 1);
> + TEST_VERIFY_EXIT (new_addr[new_size - 1] == 2);
> + xmunmap (new_addr, new_size);
> + xmunmap (old_addr, old_size);
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
>
@@ -209,6 +209,7 @@ tests += \
tst-gettid \
tst-gettid-kill \
tst-linux-mremap1 \
+ tst-linux-mremap2 \
tst-memfd_create \
tst-misalign-clone \
tst-mlock2 \
new file mode 100644
@@ -0,0 +1,54 @@
+/* Test mremap with MREMAP_DONTUNMAP.
+ Copyright (C) 2025 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 <errno.h>
+#include <sys/mman.h>
+#include <support/xstdlib.h>
+#include <support/xunistd.h>
+#include <support/check.h>
+#include <support/test-driver.h>
+#include <mremap-failure.h>
+
+static int
+do_test (void)
+{
+ size_t old_size = getpagesize ();
+ size_t new_size = old_size;
+ char *old_addr = xmmap (NULL, old_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1);
+ old_addr[0] = 1;
+ old_addr[old_size - 1] = 2;
+
+ /* Test MREMAP_DONTUNMAP w/o MREMAP_FIXED. Old address is still available. */
+ char *new_addr = mremap (old_addr, old_size, new_size,
+ MREMAP_DONTUNMAP | MREMAP_MAYMOVE, NULL);
+ if (new_addr == MAP_FAILED)
+ return mremap_failure_exit (errno);
+ /* Old range should be zero-filled. */
+ TEST_VERIFY_EXIT (old_addr[0] == 0);
+ TEST_VERIFY_EXIT (old_addr[old_size - 1] == 0);
+ /* New range should have the same bytes as the old one. */
+ TEST_VERIFY_EXIT (new_addr[0] == 1);
+ TEST_VERIFY_EXIT (new_addr[new_size - 1] == 2);
+ xmunmap (new_addr, new_size);
+ xmunmap (old_addr, old_size);
+
+ return 0;
+}
+
+#include <support/test-driver.c>