From: Miguel Martin <mmartinv@redhat.com>
To: libc-stable@sourceware.org
Cc: DJ Delorie <dj@redhat.com>, Carlos O'Donell <carlos@redhat.com>
Subject: [COMMITTED 2.34 1/2] aligned_alloc: conform to C17
Date: Tue, 21 May 2024 10:38:06 +0200 [thread overview]
Message-ID: <20240521083807.925020-2-mmartinv@redhat.com> (raw)
In-Reply-To: <20240521083807.925020-1-mmartinv@redhat.com>
From: DJ Delorie <dj@redhat.com>
This patch adds the strict checking for power-of-two alignments
in aligned_alloc(), and updates the manual accordingly.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit d1417176a35d27ffb8da0ffb1e33154163b6eeb2)
---
malloc/Makefile | 4 +-
malloc/malloc-debug.c | 9 +++-
malloc/malloc.c | 26 ++++++++--
malloc/tst-aligned-alloc-static.c | 1 +
malloc/tst-aligned-alloc.c | 80 +++++++++++++++++++++++++++++++
manual/memory.texi | 2 +-
6 files changed, 116 insertions(+), 6 deletions(-)
create mode 100644 malloc/tst-aligned-alloc-static.c
create mode 100644 malloc/tst-aligned-alloc.c
diff --git a/malloc/Makefile b/malloc/Makefile
index 9b70831d38..b02c49a687 100644
--- a/malloc/Makefile
+++ b/malloc/Makefile
@@ -43,10 +43,12 @@ tests := mallocbug tst-malloc tst-valloc tst-calloc tst-obstack \
tst-tcfree1 tst-tcfree2 tst-tcfree3 \
tst-safe-linking \
tst-mallocalign1 \
+ tst-aligned-alloc
tests-static := \
tst-interpose-static-nothread \
- tst-interpose-static-thread
+ tst-interpose-static-thread \
+ tst-aligned-alloc-static
# Test for the malloc_set_state symbol removed in glibc 2.25.
ifeq ($(have-GLIBC_2.23)$(build-shared),yesyes)
diff --git a/malloc/malloc-debug.c b/malloc/malloc-debug.c
index 3d7e6d44fd..95ad42b68e 100644
--- a/malloc/malloc-debug.c
+++ b/malloc/malloc-debug.c
@@ -300,7 +300,14 @@ __debug_memalign (size_t alignment, size_t bytes)
return _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0));
}
strong_alias (__debug_memalign, memalign)
-strong_alias (__debug_memalign, aligned_alloc)
+static void *
+__debug_aligned_alloc (size_t alignment, size_t bytes)
+{
+ if (!powerof2 (alignment) || alignment == 0)
+ return NULL;
+ return _debug_mid_memalign (alignment, bytes, RETURN_ADDRESS (0));
+}
+strong_alias (__debug_aligned_alloc, aligned_alloc)
static void *
__debug_pvalloc (size_t bytes)
diff --git a/malloc/malloc.c b/malloc/malloc.c
index d31e985ecc..5ce3223777 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3407,6 +3407,29 @@ __libc_memalign (size_t alignment, size_t bytes)
void *address = RETURN_ADDRESS (0);
return _mid_memalign (alignment, bytes, address);
}
+libc_hidden_def (__libc_memalign)
+
+/* For ISO C17. */
+void *
+weak_function
+aligned_alloc (size_t alignment, size_t bytes)
+{
+ if (!__malloc_initialized)
+ ptmalloc_init ();
+
+/* Similar to memalign, but starting with ISO C17 the standard
+ requires an error for alignments that are not supported by the
+ implementation. Valid alignments for the current implementation
+ are non-negative powers of two. */
+ if (!powerof2 (alignment) || alignment == 0)
+ {
+ __set_errno (EINVAL);
+ return 0;
+ }
+
+ void *address = RETURN_ADDRESS (0);
+ return _mid_memalign (alignment, bytes, address);
+}
static void *
_mid_memalign (size_t alignment, size_t bytes, void *address)
@@ -3465,9 +3488,6 @@ _mid_memalign (size_t alignment, size_t bytes, void *address)
ar_ptr == arena_for_chunk (mem2chunk (p)));
return tag_new_usable (p);
}
-/* For ISO C11. */
-weak_alias (__libc_memalign, aligned_alloc)
-libc_hidden_def (__libc_memalign)
void *
__libc_valloc (size_t bytes)
diff --git a/malloc/tst-aligned-alloc-static.c b/malloc/tst-aligned-alloc-static.c
new file mode 100644
index 0000000000..d504473094
--- /dev/null
+++ b/malloc/tst-aligned-alloc-static.c
@@ -0,0 +1 @@
+#include "tst-aligned-alloc.c"
diff --git a/malloc/tst-aligned-alloc.c b/malloc/tst-aligned-alloc.c
new file mode 100644
index 0000000000..8bd6527147
--- /dev/null
+++ b/malloc/tst-aligned-alloc.c
@@ -0,0 +1,80 @@
+/* Test for C17 alignment requirements.
+ Copyright (C) 2023 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 <malloc.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libc-diag.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+ void *p1;
+ void *p2;
+ void *p3;
+ void *p4;
+ void *p5;
+
+ errno = 0;
+
+ /* The implementation supports alignments that are non-negative powers of 2.
+ We test 5 distinct conditions here:
+ - A non-negative power of 2 alignment e.g. 64.
+ - A degenerate zero power of 2 alignment e.g. 1.
+ - A non-power-of-2 alignment e.g. 65.
+ - A zero alignment.
+ - A corner case SIZE_MAX / 2 + 1 alignment.
+ */
+
+ p1 = aligned_alloc (64, 64);
+
+ if (p1 == NULL)
+ FAIL_EXIT1 ("aligned_alloc(64, 64) failed");
+
+ p2 = aligned_alloc (1, 64);
+
+ if (p2 == NULL)
+ FAIL_EXIT1 ("aligned_alloc(1, 64) failed");
+
+ p3 = aligned_alloc (65, 64);
+
+ if (p3 != NULL)
+ FAIL_EXIT1 ("aligned_alloc(65, 64) did not fail");
+
+ p4 = aligned_alloc (0, 64);
+
+ if (p4 != NULL)
+ FAIL_EXIT1 ("aligned_alloc(0, 64) did not fail");
+
+ /* This is an alignment like 0x80000000...UL */
+ p5 = aligned_alloc (SIZE_MAX / 2 + 1, 64);
+
+ if (p5 != NULL)
+ FAIL_EXIT1 ("aligned_alloc(SIZE_MAX/2+1, 64) did not fail");
+
+ free (p1);
+ free (p2);
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/manual/memory.texi b/manual/memory.texi
index 0b2b9c8795..5c16f7aee6 100644
--- a/manual/memory.texi
+++ b/manual/memory.texi
@@ -995,7 +995,7 @@ power of two than that, use @code{aligned_alloc} or @code{posix_memalign}.
@c Alias to memalign.
The @code{aligned_alloc} function allocates a block of @var{size} bytes whose
address is a multiple of @var{alignment}. The @var{alignment} must be a
-power of two and @var{size} must be a multiple of @var{alignment}.
+power of two.
The @code{aligned_alloc} function returns a null pointer on error and sets
@code{errno} to one of the following values:
--
2.45.1
next prev parent reply other threads:[~2024-05-21 8:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-21 8:38 [COMMITTED 2.34 0/2] Improve aligned_alloc and calloc test coverage Miguel Martin
2024-05-21 8:38 ` Miguel Martin [this message]
2024-05-21 8:38 ` [COMMITTED 2.34 2/2] malloc: " Miguel Martin
2024-05-21 10:42 ` Florian Weimer
2024-05-21 13:00 ` Miguel Martín
2024-05-21 13:06 ` Adhemerval Zanella Netto
2024-05-21 13:30 ` Miguel Martín
2024-05-21 13:32 ` Sam James
2024-05-21 13:24 ` Florian Weimer
2024-05-21 10:43 ` [COMMITTED 2.34 0/2] " Florian Weimer
2024-05-21 12:12 ` Miguel Martín
2024-05-21 12:51 ` Miguel Martín
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