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authorJörg Frings-Fürst <debian@jff.email>2022-02-07 06:57:44 +0100
committerJörg Frings-Fürst <debian@jff.email>2022-02-07 06:57:44 +0100
commit6ffaa52cf732a84c0f8259dbc9b8183960ec5c33 (patch)
treed3136c22e3e805cfc0efe78412cce905a17e0c8d /tests/test-free.c
parent591cbf5878b7d4105b275585b9db1324c9dfce56 (diff)
parentaf151c593704a40e10efb28d1e3dd59a23a661f3 (diff)
Merge branch 'release/debian/1.0-1'debian/1.0-1
Diffstat (limited to 'tests/test-free.c')
-rw-r--r--tests/test-free.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/tests/test-free.c b/tests/test-free.c
new file mode 100644
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--- /dev/null
+++ b/tests/test-free.c
@@ -0,0 +1,175 @@
+/* Test of free() function.
+ Copyright (C) 2020-2022 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 3 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/>. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2020. */
+
+#include <config.h>
+
+/* Specification. */
+#include <stdlib.h>
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#if defined __linux__
+# include <fcntl.h>
+# include <stdint.h>
+# include <string.h>
+# include <sys/mman.h>
+#endif
+
+#include "macros.h"
+
+/* The indirection through a volatile function pointer is necessary to prevent
+ a GCC optimization. Without it, when optimizing, GCC would "know" that errno
+ is unchanged by calling free(ptr), when ptr was the result of a malloc(...)
+ call in the same function. */
+static int
+get_errno (void)
+{
+ volatile int err = errno;
+ return err;
+}
+
+static int (* volatile get_errno_func) (void) = get_errno;
+
+int
+main ()
+{
+ /* Check that free() preserves errno. */
+ {
+ errno = 1789; /* Liberté, égalité, fraternité. */
+ free (NULL);
+ ASSERT_NO_STDIO (get_errno_func () == 1789);
+ }
+ { /* Small memory allocations. */
+ #define N 10000
+ void * volatile ptrs[N];
+ size_t i;
+ for (i = 0; i < N; i++)
+ ptrs[i] = malloc (15);
+ for (i = 0; i < N; i++)
+ {
+ errno = 1789;
+ free (ptrs[i]);
+ ASSERT_NO_STDIO (get_errno_func () == 1789);
+ }
+ #undef N
+ }
+ { /* Medium memory allocations. */
+ #define N 1000
+ void * volatile ptrs[N];
+ size_t i;
+ for (i = 0; i < N; i++)
+ ptrs[i] = malloc (729);
+ for (i = 0; i < N; i++)
+ {
+ errno = 1789;
+ free (ptrs[i]);
+ ASSERT_NO_STDIO (get_errno_func () == 1789);
+ }
+ #undef N
+ }
+ { /* Large memory allocations. */
+ #define N 10
+ void * volatile ptrs[N];
+ size_t i;
+ for (i = 0; i < N; i++)
+ ptrs[i] = malloc (5318153);
+ for (i = 0; i < N; i++)
+ {
+ errno = 1789;
+ free (ptrs[i]);
+ ASSERT_NO_STDIO (get_errno_func () == 1789);
+ }
+ #undef N
+ }
+
+ /* Test a less common code path.
+ When malloc() is based on mmap(), free() can sometimes call munmap().
+ munmap() usually succeeds, but fails in a particular situation: when
+ - it has to unmap the middle part of a VMA, and
+ - the number of VMAs of a process is limited and the limit is
+ already reached.
+ The latter condition is fulfilled on Linux, when the file
+ /proc/sys/vm/max_map_count exists. This file contains the limit
+ - for Linux >= 2.4.19: 65536 (DEFAULT_MAX_MAP_COUNT in linux/include/linux/sched.h)
+ - for Linux >= 2.6.31: 65530 (DEFAULT_MAX_MAP_COUNT in linux/include/linux/mm.h).
+ But do not test it with glibc < 2.15, since that triggers a glibc internal
+ abort: "malloc.c:3551: munmap_chunk: Assertion `ret == 0' failed."
+ */
+ #if defined __linux__ && !(__GLIBC__ == 2 && __GLIBC_MINOR__ < 15)
+ if (open ("/proc/sys/vm/max_map_count", O_RDONLY) >= 0)
+ {
+ /* Preparations. */
+ size_t pagesize = getpagesize ();
+ void *firstpage_backup = malloc (pagesize);
+ void *lastpage_backup = malloc (pagesize);
+ /* Allocate a large memory area, as a bumper, so that the MAP_FIXED
+ allocation later will not overwrite parts of the memory areas
+ allocated to ld.so or libc.so. */
+ void *bumper_region =
+ mmap (NULL, 0x1000000, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+ /* A file descriptor pointing to a regular file. */
+ int fd = open ("test-free", O_RDONLY);
+
+ if (firstpage_backup != NULL && lastpage_backup != NULL
+ && bumper_region != (void *)(-1)
+ && fd >= 0)
+ {
+ /* Do a large memory allocation. */
+ size_t big_size = 0x1000000;
+ void * volatile ptr = malloc (big_size - 0x100);
+ char *ptr_aligned = (char *) ((uintptr_t) ptr & ~(pagesize - 1));
+ /* This large memory allocation allocated a memory area
+ from ptr_aligned to ptr_aligned + big_size.
+ Enlarge this memory area by adding a page before and a page
+ after it. */
+ memcpy (firstpage_backup, ptr_aligned, pagesize);
+ memcpy (lastpage_backup, ptr_aligned + big_size - pagesize, pagesize);
+ if (mmap (ptr_aligned - pagesize, pagesize + big_size + pagesize,
+ PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0)
+ != (void *)(-1))
+ {
+ memcpy (ptr_aligned, firstpage_backup, pagesize);
+ memcpy (ptr_aligned + big_size - pagesize, lastpage_backup, pagesize);
+
+ /* Now add as many mappings as we can.
+ Stop at 65536, in order not to crash the machine (in case the
+ limit has been increased by the system administrator). */
+ size_t i;
+ for (i = 0; i < 65536; i++)
+ if (mmap (NULL, pagesize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0)
+ == (void *)(-1))
+ break;
+ /* Now the number of VMAs of this process has hopefully attained
+ its limit. */
+
+ errno = 1789;
+ /* This call to free() is supposed to call
+ munmap (ptr_aligned, big_size);
+ which increases the number of VMAs by 1, which is supposed
+ to fail. */
+ free (ptr);
+ ASSERT_NO_STDIO (get_errno_func () == 1789);
+ }
+ }
+ }
+ #endif
+
+ return 0;
+}