systemd/0268-memory-util-add-a-concept-for-gcc-cleanup-attribute-.patch
Jan Macku 5f20544e0d systemd-252-16
Resolves: #2169959,#2170883,#2172509,#2176899,#2182632,#2193456,#2208240,#2210145,#2210237,#2212612,#2215412,#2218184,#2218886
2023-07-17 09:28:26 +02:00

134 lines
4.3 KiB
Diff

From f49fbc3ebbb026f87b974c11c40808cc777bd277 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 22 Feb 2023 23:10:25 +0100
Subject: [PATCH] memory-util: add a concept for gcc cleanup attribute based
array destruction
(cherry picked from commit ff3f1464ec2dd40c9d8eb92e1474cb4d1c8c676b)
Related: #2182632
---
src/basic/alloc-util.h | 1 +
src/basic/memory-util.h | 34 +++++++++++++++++++++++++++++
src/test/meson.build | 2 ++
src/test/test-memory-util.c | 43 +++++++++++++++++++++++++++++++++++++
4 files changed, 80 insertions(+)
create mode 100644 src/test/test-memory-util.c
diff --git a/src/basic/alloc-util.h b/src/basic/alloc-util.h
index b38db7d473..e4c8b71a2b 100644
--- a/src/basic/alloc-util.h
+++ b/src/basic/alloc-util.h
@@ -14,6 +14,7 @@
typedef void (*free_func_t)(void *p);
typedef void* (*mfree_func_t)(void *p);
+typedef void (*free_array_func_t)(void *p, size_t n);
/* If for some reason more than 4M are allocated on the stack, let's abort immediately. It's better than
* proceeding and smashing the stack limits. Note that by default RLIMIT_STACK is 8M on Linux. */
diff --git a/src/basic/memory-util.h b/src/basic/memory-util.h
index 6e3280b9df..8d75befed5 100644
--- a/src/basic/memory-util.h
+++ b/src/basic/memory-util.h
@@ -121,3 +121,37 @@ static inline void erase_and_freep(void *p) {
static inline void erase_char(char *p) {
explicit_bzero_safe(p, sizeof(char));
}
+
+/* An automatic _cleanup_-like logic for destroy arrays (i.e. pointers + size) when leaving scope */
+struct ArrayCleanup {
+ void **parray;
+ size_t *pn;
+ free_array_func_t pfunc;
+};
+
+static inline void array_cleanup(struct ArrayCleanup *c) {
+ assert(c);
+
+ assert(!c->parray == !c->pn);
+
+ if (!c->parray)
+ return;
+
+ if (*c->parray) {
+ assert(c->pfunc);
+ c->pfunc(*c->parray, *c->pn);
+ *c->parray = NULL;
+ }
+
+ *c->pn = 0;
+}
+
+#define CLEANUP_ARRAY(array, n, func) \
+ _cleanup_(array_cleanup) _unused_ struct ArrayCleanup CONCATENATE(_cleanup_array_, UNIQ) = { \
+ .parray = (void**) &(array), \
+ .pn = &(n), \
+ .pfunc = (free_array_func_t) ({ \
+ void (*_f)(typeof(array[0]) *a, size_t b) = func; \
+ _f; \
+ }), \
+ }
diff --git a/src/test/meson.build b/src/test/meson.build
index 2a4dfe26db..536ab08652 100644
--- a/src/test/meson.build
+++ b/src/test/meson.build
@@ -213,6 +213,8 @@ tests += [
[],
[libm]],
+ [files('test-memory-util.c')],
+
[files('test-mkdir.c')],
[files('test-json.c'),
diff --git a/src/test/test-memory-util.c b/src/test/test-memory-util.c
new file mode 100644
index 0000000000..a81b0e0120
--- /dev/null
+++ b/src/test/test-memory-util.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "memory-util.h"
+#include "tests.h"
+
+static void my_destructor(struct iovec *iov, size_t n) {
+ /* not really a destructor, just something we can use to check if the destruction worked */
+ memset(iov, 'y', sizeof(struct iovec) * n);
+}
+
+TEST(cleanup_array) {
+ struct iovec *iov, *saved_iov;
+ size_t n, saved_n;
+
+ n = 7;
+ iov = new(struct iovec, n);
+ assert_se(iov);
+
+ memset(iov, 'x', sizeof(struct iovec) * n);
+
+ saved_iov = iov;
+ saved_n = n;
+
+ {
+ assert_se(memeqbyte('x', saved_iov, sizeof(struct iovec) * saved_n));
+ assert_se(iov);
+ assert_se(n > 0);
+
+ CLEANUP_ARRAY(iov, n, my_destructor);
+
+ assert_se(memeqbyte('x', saved_iov, sizeof(struct iovec) * saved_n));
+ assert_se(iov);
+ assert_se(n > 0);
+ }
+
+ assert_se(memeqbyte('y', saved_iov, sizeof(struct iovec) * saved_n));
+ assert_se(!iov);
+ assert_se(n == 0);
+
+ free(saved_iov);
+}
+
+DEFINE_TEST_MAIN(LOG_INFO);