Re: [PATCH 2/2] add preinit_array support

[Szabolcs Nagy <nsz@port70.net>]

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* Szabolcs Nagy <nsz@port70.net> [2015-11-29 16:33:22 +0100]:
> redefined DYN_CNT because 32 is not enough for DT_PREINIT_ARRAY.
> ---
>  src/env/__libc_start_main.c |  5 +++++
>  src/ldso/dynlink.c          | 12 ++++++++++--
>  2 files changed, 15 insertions(+), 2 deletions(-)
> 

src/internal change was missing and legacy _init vs
preinit_array order was wrong.

attached new version, array type is fixed too.

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From 8820faea5a365387c8fe54c8ffa1f796c2084f83 Mon Sep 17 00:00:00 2001
From: Szabolcs Nagy <nsz@port70.net>
Date: Sun, 29 Nov 2015 16:36:24 +0000
Subject: [PATCH 2/2] add preinit_array support

handle DT_PREINIT_ARRAY{SZ} in case of dynamic linking and
__preinit_array_{start,end} in case of static linking.

redefined DYN_CNT because 32 is not enough for DT_PREINIT_ARRAY.
---
 src/env/__libc_start_main.c |  5 +++++
 src/internal/dynlink.h      |  2 +-
 src/ldso/dynlink.c          | 12 ++++++++++--
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/env/__libc_start_main.c b/src/env/__libc_start_main.c
index 14a2825..7502bc3 100644
--- a/src/env/__libc_start_main.c
+++ b/src/env/__libc_start_main.c
@@ -12,6 +12,9 @@ static void dummy(void) {}
 weak_alias(dummy, _init);
 
 __attribute__((__weak__, __visibility__("hidden")))
+extern void (*const __preinit_array_start)(void), (*const __preinit_array_end)(void);
+
+__attribute__((__weak__, __visibility__("hidden")))
 extern void (*const __init_array_start)(void), (*const __init_array_end)(void);
 
 static void dummy1(void *p) {}
@@ -56,6 +59,8 @@ void __init_libc(char **envp, char *pn)
 static void libc_start_init(void)
 {
 	void (*const *f)(void);
+	for (f=&__preinit_array_start; f<&__preinit_array_end; f++)
+		(*f)();
 	_init();
 	for (f=&__init_array_start; f<&__init_array_end; f++)
 		(*f)();
diff --git a/src/internal/dynlink.h b/src/internal/dynlink.h
index 9c494e4..fb706d3 100644
--- a/src/internal/dynlink.h
+++ b/src/internal/dynlink.h
@@ -84,7 +84,7 @@ struct fdpic_dummy_loadmap {
 #endif
 
 #define AUX_CNT 32
-#define DYN_CNT 32
+#define DYN_CNT DT_NUM
 
 typedef void (*stage2_func)(unsigned char *, size_t *);
 typedef _Noreturn void (*stage3_func)(size_t *);
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 93e7d67..51da820 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -135,11 +135,14 @@ static struct fdpic_dummy_loadmap app_dummy_loadmap;
 struct debug *_dl_debug_addr = &debug;
 
 __attribute__((__visibility__("hidden")))
-void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
+void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0,
+(*const __preinit_array_start)(void)=0;
 
 __attribute__((__visibility__("hidden")))
-extern void (*const __init_array_end)(void), (*const __fini_array_end)(void);
+extern void (*const __init_array_end)(void), (*const __fini_array_end)(void),
+(*const __preinit_array_end)(void);
 
+weak_alias(__preinit_array_start, __preinit_array_end);
 weak_alias(__init_array_start, __init_array_end);
 weak_alias(__fini_array_start, __fini_array_end);
 
@@ -1225,6 +1228,11 @@ static void do_init_fini(struct dso *p)
 			p->fini_next = fini_head;
 			fini_head = p;
 		}
+		if (dyn[0] & (1UL<<DT_PREINIT_ARRAY)) {
+			size_t n = dyn[DT_PREINIT_ARRAYSZ]/sizeof(size_t);
+			size_t *fn = laddr(p, dyn[DT_PREINIT_ARRAY]);
+			while (n--) ((void (*)(void))*fn++)();
+		}
 #ifndef NO_LEGACY_INITFINI
 		if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 			fpaddr(p, dyn[DT_INIT])();
-- 
2.4.1