From: "Paul E. McKenney" <[email protected]>
To: [email protected]
Cc: [email protected], [email protected], [email protected],
"Thomas Weißschuh" <[email protected]>,
"Willy Tarreau" <[email protected]>
Subject: [PATCH nolibc 17/19] tools/nolibc: add support for constructors and destructors
Date: Thu, 12 Oct 2023 12:32:31 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <b34ce3cf-3fcc-4eb0-a658-229c197455ef@paulmck-laptop>
From: Thomas Weißschuh <[email protected]>
With the startup code moved to C, implementing support for
constructors and deconstructors is fairly easy to implement.
Examples for code size impact:
text data bss dec hex filename
21837 104 88 22029 560d nolibc-test.before
22135 120 88 22343 5747 nolibc-test.after
21970 104 88 22162 5692 nolibc-test.after-only-crt.h-changes
The sections are defined by [0].
[0] https://refspecs.linuxfoundation.org/elf/gabi4+/ch5.dynamic.html
Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Willy Tarreau <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
---
tools/include/nolibc/crt.h | 23 +++++++++++++++++++-
tools/testing/selftests/nolibc/nolibc-test.c | 17 +++++++++++++++
2 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
index a05655b4ce1d..43b551468c2a 100644
--- a/tools/include/nolibc/crt.h
+++ b/tools/include/nolibc/crt.h
@@ -13,12 +13,23 @@ const unsigned long *_auxv __attribute__((weak));
static void __stack_chk_init(void);
static void exit(int);
+extern void (*const __preinit_array_start[])(void) __attribute__((weak));
+extern void (*const __preinit_array_end[])(void) __attribute__((weak));
+
+extern void (*const __init_array_start[])(void) __attribute__((weak));
+extern void (*const __init_array_end[])(void) __attribute__((weak));
+
+extern void (*const __fini_array_start[])(void) __attribute__((weak));
+extern void (*const __fini_array_end[])(void) __attribute__((weak));
+
__attribute__((weak))
void _start_c(long *sp)
{
long argc;
char **argv;
char **envp;
+ int exitcode;
+ void (* const *func)(void);
const unsigned long *auxv;
/* silence potential warning: conflicting types for 'main' */
int _nolibc_main(int, char **, char **) __asm__ ("main");
@@ -55,8 +66,18 @@ void _start_c(long *sp)
;
_auxv = auxv;
+ for (func = __preinit_array_start; func < __preinit_array_end; func++)
+ (*func)();
+ for (func = __init_array_start; func < __init_array_end; func++)
+ (*func)();
+
/* go to application */
- exit(_nolibc_main(argc, argv, envp));
+ exitcode = _nolibc_main(argc, argv, envp);
+
+ for (func = __fini_array_end; func > __fini_array_start;)
+ (*--func)();
+
+ exit(exitcode);
}
#endif /* _NOLIBC_CRT_H */
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 7e3936c182dc..8da7f15d010e 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -57,6 +57,9 @@ static int test_argc;
/* will be used by some test cases as readable file, please don't write it */
static const char *argv0;
+/* will be used by constructor tests */
+static int constructor_test_value;
+
/* definition of a series of tests */
struct test {
const char *name; /* test name */
@@ -594,6 +597,19 @@ int expect_strne(const char *expr, int llen, const char *cmp)
#define CASE_TEST(name) \
case __LINE__: llen += printf("%d %s", test, #name);
+/* constructors validate that they are executed in definition order */
+__attribute__((constructor))
+static void constructor1(void)
+{
+ constructor_test_value = 1;
+}
+
+__attribute__((constructor))
+static void constructor2(void)
+{
+ constructor_test_value *= 2;
+}
+
int run_startup(int min, int max)
{
int test;
@@ -630,6 +646,7 @@ int run_startup(int min, int max)
CASE_TEST(environ_HOME); EXPECT_PTRNZ(1, getenv("HOME")); break;
CASE_TEST(auxv_addr); EXPECT_PTRGT(test_auxv != (void *)-1, test_auxv, brk); break;
CASE_TEST(auxv_AT_UID); EXPECT_EQ(1, getauxval(AT_UID), getuid()); break;
+ CASE_TEST(constructor); EXPECT_EQ(1, constructor_test_value, 2); break;
case __LINE__:
return ret; /* must be last */
/* note: do not set any defaults so as to permit holes above */
--
2.40.1
next prev parent reply other threads:[~2023-10-12 19:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-12 19:32 [PATCH nolibc 0/19] Updates to nolibc for v6.7 (and three for v6.6) Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 01/19] tools/nolibc: i386: Fix a stack misalign bug on _start Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 02/19] MAINTAINERS: nolibc: update tree location Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 03/19] tools/nolibc: mark start_c as weak Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 04/19] tools/nolibc: add stdarg.h header Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 05/19] selftests/nolibc: use -nostdinc for nolibc-test Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 06/19] tools/nolibc: x86-64: Use `rep movsb` for `memcpy()` and `memmove()` Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 07/19] tools/nolibc: x86-64: Use `rep stosb` for `memset()` Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 08/19] tools/nolibc: string: Remove the `_nolibc_memcpy_down()` function Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 09/19] tools/nolibc: string: Remove the `_nolibc_memcpy_up()` function Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 10/19] selftests/nolibc: libc-test: avoid -Wstringop-overflow warnings Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 11/19] selftests/nolibc: don't embed initramfs into kernel image Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 12/19] selftests/nolibc: allow building i386 with multiarch compiler Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 13/19] tools/nolibc: avoid unused parameter warnings for ENOSYS fallbacks Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 14/19] tools/nolibc: don't define new syscall number Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 15/19] tools/nolibc: automatically detect necessity to use pselect6 Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 16/19] tools/nolibc: drop test for getauxval(AT_PAGESZ) Paul E. McKenney
2023-10-12 19:32 ` Paul E. McKenney [this message]
2023-10-12 19:32 ` [PATCH nolibc 18/19] selftests/nolibc: use qemu-system-ppc64 for ppc64le Paul E. McKenney
2023-10-12 19:32 ` [PATCH nolibc 19/19] selftests/nolibc: add tests for multi-object linkage Paul E. McKenney
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