This commit contains a patch from Stefan Allius <allius@atecom.com> to change

how uClibc handles _init and _fini, allowing shared lib constructors and
destructors to initialize things in the correct sequence.  Stefan ported the SH
architecture.  I then ported x86, arm, and mips.  x86 and arm are working fine,
but I don't think I quite got things correct for mips.

6 files changed, 185 insertions, 107 deletions

diff --git a/libc/Makefile b/libc/Makefile
index 401a56695..1809779d6 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -53,9 +53,9 @@ shared: $(TOPDIR)lib/$(LIBNAME)
 		/bin/sh $(TOPDIR)../extra/scripts/get-needed-libgcc-objects.sh)
 	$(LD) $(LDFLAGS) $(VERSION_SCRIPT) -soname=$(SHARED_MAJORNAME) -o $(SHARED_FULLNAME) \
 		--whole-archive ./tmp/libgcc-need.a $(LIBNAME) --no-whole-archive \
-		$(TOPDIR)/libc/misc/internals/interp.o \
+		-init __uClibc_init $(TOPDIR)/libc/misc/internals/interp.o \
 		$(LIBGCC)
-	@/bin/true #rm -rf tmp
+	@true #rm -rf tmp
 	install -d $(TOPDIR)lib
 	rm -f $(TOPDIR)lib/$(SHARED_FULLNAME)
 	install -m 644 $(SHARED_FULLNAME) $(TOPDIR)lib
diff --git a/libc/misc/internals/__uClibc_main.c b/libc/misc/internals/__uClibc_main.c
index 53f897d9f..aa4655cec 100644
--- a/libc/misc/internals/__uClibc_main.c
+++ b/libc/misc/internals/__uClibc_main.c
@@ -20,8 +20,6 @@
  * Prototypes.
  */
 extern int  main(int argc, char **argv, char **envp);
-extern void weak_function _init(void);
-extern void weak_function _fini(void);
 extern void weak_function _stdio_init(void);
 extern int *weak_const_function __errno_location(void);
 extern int *weak_const_function __h_errno_location(void);
@@ -36,10 +34,11 @@ extern void weak_function __pthread_initialize_minimal(void);
 
 
 
+
 /*
  * Declare the __environ global variable and create a weak alias environ.
- * Note: Apparently we must initialize __environ for the weak environ
- * symbol to be included.
+ * Note: Apparently we must initialize __environ to ensure that the weak 
+ * environ symbol is also included.
  */
 
 char **__environ = 0;
@@ -47,68 +46,124 @@ weak_alias(__environ, environ);
 
 
 
+/* __uClibc_init completely initialize uClibc so it is ready to use.
+ *
+ * On ELF systems (with a dynamic loader) this function must be called
+ * from the dynamic loader (see TIS and ELF Specification), so that
+ * constructors of shared libraries (which depend on libc) can use all
+ * the libc code without restriction.  For this we link the shared
+ * version of the uClibc with -init __uClibc_init so DT_INIT for
+ * uClibc is the address of __uClibc_init
+ * 
+ * In all other cases we call it from the main stub
+ * __uClibc_start_main.
+ */
 
-void __attribute__ ((__noreturn__)) 
-__uClibc_main(int argc, char **argv, char **envp) 
+void __uClibc_init(void) 
 {
-	/* If we are dynamically linked the shared lib loader
-	 * already did this for us.  But if we are statically
-	 * linked, we need to do this for ourselves. */
-	if (__environ==NULL) {
-		/* Statically linked. */ 
-		__environ = envp;
-	}
+    static int been_there_done_that = 0;
+
+    if (been_there_done_that) 
+	return;
+    been_there_done_that++;
 
 #ifdef __UCLIBC_HAS_THREADS__
-	if (likely(__pthread_initialize_minimal!=NULL))
-	    __pthread_initialize_minimal();
+    /* Before we start initialzing uClibc we have to call
+     * __pthread_initialize_minimal so we can use pthread_locks 
+     * whenever they are needed.
+     */
+    if (likely(__pthread_initialize_minimal!=NULL))
+	__pthread_initialize_minimal();
 #endif
 
 #if 0
-	/* Some security at this point.  Prevent starting a SUID binary
-	 * where the standard file descriptors are not opened.  We have
-	 * to do this only for statically linked applications since
-	 * otherwise the dynamic loader did the work already.  */
-	if (unlikely (__libc_enable_secure!=NULL))
-		__libc_check_standard_fds ();
+    /* Some security at this point.  Prevent starting a SUID binary
+     * where the standard file descriptors are not opened.  We have
+     * to do this only for statically linked applications since
+     * otherwise the dynamic loader did the work already.  */
+    if (unlikely (__libc_enable_secure!=NULL))
+	__libc_check_standard_fds ();
 #endif
 
 #ifdef __UCLIBC_HAS_LOCALE__
-	/* Initialize the global locale structure. */
-	if (likely(_locale_init!=NULL))
-	    _locale_init();
+    /* Initialize the global locale structure. */
+    if (likely(_locale_init!=NULL))
+	_locale_init();
 #endif
 
-	/*
-	 * Initialize stdio here.  In the static library case, this will
-	 * be bypassed if not needed because of the weak alias above.
-	 */
-	if (likely(_stdio_init != NULL))
-		_stdio_init();
-
-	/* Arrange for dtors to run at exit.  */
-	if (likely(_fini!=NULL && atexit)) {
-		atexit (&_fini);
-	}
-
-	/* Run all ctors now.  */
-	if (likely(_init!=NULL))
-		_init();
-
-	/*
-	 * Note: It is possible that any initialization done above could
-	 * have resulted in errno being set nonzero, so set it to 0 before
-	 * we call main.
-	 */
-	if (likely(__errno_location!=NULL))
-		*(__errno_location()) = 0;
-
-	/* Set h_errno to 0 as well */
-	if (likely(__h_errno_location!=NULL))
-		*(__h_errno_location()) = 0;
-
-	/*
-	 * Finally, invoke application's main and then exit.
-	 */
-	exit(main(argc, argv, envp));
+    /*
+     * Initialize stdio here.  In the static library case, this will
+     * be bypassed if not needed because of the weak alias above.
+     */
+    if (likely(_stdio_init != NULL))
+	_stdio_init();
+
+}
+
+
+/* __uClibc_start_main is the new main stub for uClibc. This function is 
+ * called from crt0 (version 0.9.16 or newer), after ALL shared libraries 
+ * are initialized, just before we call the application's main function.
+ */
+void __attribute__ ((__noreturn__)) 
+__uClibc_start_main(int argc, char **argv, char **envp, 
+	void (*app_init)(void), void (*app_fini)(void))
+{
+
+    /* If we are dynamically linked the shared lib loader already
+     * did this for us.  But if we are statically linked, we need
+     * to do this for ourselves.  */
+    if (__environ==NULL) {
+	/* Statically linked. */ 
+	__environ = envp;
+    }
+
+    /* We need to initialize uClibc.  If we are dynamically linked this
+     * may have already been completed by the shared lib loader.  We call 
+     * __uClibc_init() regardless, to be sure the right thing happens. */
+    __uClibc_init();
+
+    /* Arrange for the application's dtors to run before we exit.  */
+    if (app_fini!=NULL && atexit) {
+	atexit (app_fini);
+    }
+
+    /* Run all the application's ctors now.  */
+    if (app_init!=NULL) {
+	app_init();
+    }
+
+    /* Note: It is possible that any initialization done above could
+     * have resulted in errno being set nonzero, so set it to 0 before
+     * we call main.
+     */
+    if (likely(__errno_location!=NULL))
+	*(__errno_location()) = 0;
+
+    /* Set h_errno to 0 as well */
+    if (likely(__h_errno_location!=NULL))
+	*(__h_errno_location()) = 0;
+
+    /*
+     * Finally, invoke application's main and then exit.
+     */
+    exit(main(argc, argv, envp));
+}
+
+
+/* __uClibc_main is the old main stub of the uClibc. This
+ * function is called from crt0 (uClibc 0.9.15 and older) after
+ * ALL shared libraries are initialized, and just before we call
+ * the application's main() function.  
+ *
+ * Attention: This stub does not call the .init/.fini sections of
+ * the application. If you need this, please fix your uClibc port
+ * so that  __uClibc_start_main is called by your crt0.S with
+ * _init and _fini properly set.
+*/
+void __attribute__ ((__noreturn__)) 
+__uClibc_main(int argc, char **argv, char ** envp)
+{
+    __uClibc_start_main(argc, argv, envp, NULL, NULL);
 }
+
diff --git a/libc/sysdeps/linux/arm/crt0.S b/libc/sysdeps/linux/arm/crt0.S
index 442c9e84b..dc0ec87d8 100644
--- a/libc/sysdeps/linux/arm/crt0.S
+++ b/libc/sysdeps/linux/arm/crt0.S
@@ -50,20 +50,10 @@ ARM register quick reference:
 
 .text
 	.global _start
-	.global __uClibc_main
-
 	.type   _start,%function
-	.type   __uClibc_main,%function
 
 .text
 _start:
-#if 0 /* some old code the I feel should not be here - davidm */
-	@ adjust the data segment base pointer
-	ldr r3,=__data_start
-	sub sl,sl,r3
-	mov BASEREG,sl
-#endif
-
 	/* clear the frame pointer */
 	mov     fp, #0
 
@@ -78,10 +68,11 @@ _start:
 	   we find there (hopefully the environment) in r2 */
 	add     r2, r1, r0, lsl #2
 	add     r2, r2, #4
+
 #else
 	/*
-	 * uClinux stacks look a little different to MMU stacks
-	 * for no good reason
+	 * uClinux stacks look a little different from normal
+	 * MMU-full Linux stacks (for no good reason)
 	 */
 	/* pull argc, argv and envp off the stack */
 	ldr r0,[sp, #0]
@@ -89,8 +80,19 @@ _start:
 	ldr r2,[sp, #8]
 #endif
 
+	/* Store the address of _init in r3 as an argument to main() */
+	ldr r3, =_init
+
+	/* Push _fini onto the stack as the final argument to main() */
+	stmfd sp!, {r0}
+	ldr a1, =_fini
+	stmfd sp!, {r0}
+
 	/* Ok, now run uClibc's main() -- shouldn't return */
-	bl	__uClibc_main
+	bl	__uClibc_start_main
+
+	/* Crash if somehow `exit' returns anyways.  */
+	bl abort
 
 /* Stick in a dummy reference to main(), so that if an application
  * is linking when the main() function is in a static library (.a)
diff --git a/libc/sysdeps/linux/i386/crt0.S b/libc/sysdeps/linux/i386/crt0.S
index 3623fe821..97f1fde63 100644
--- a/libc/sysdeps/linux/i386/crt0.S
+++ b/libc/sysdeps/linux/i386/crt0.S
@@ -33,11 +33,11 @@ Cambridge, MA 02139, USA.  */
 .text
 	.align 4
 
-.globl _start
-	.type	 _start,@function
+	.globl _start
+	.type _start,@function
 
 _start:
-	/* First locate the start of the environment variables */
+	/* locate the start of the environment variables */
 	popl %ecx	/* Store argc into %ecx */
 	movl %esp,%ebx  /* Store argv into ebx */
 	movl %esp,%eax  /* Store argv into eax as well*/
@@ -52,7 +52,6 @@ _start:
 	    %eax = env	    ; argv + (argc * 4) + 4
 	*/
 
-
 	/* Set up an invalid (NULL return address, NULL frame pointer)
 	   callers stack frame so anybody unrolling the stack knows where
 	   to stop */
@@ -62,20 +61,18 @@ _start:
 	pushl %ebp      /* callers %ebp (frame pointer) */
 	movl %esp,%ebp  /* mark callers stack frame as invalid */
 
-	/* Now set the environment, argc, and argv where the app can get to them */
-	pushl %eax      /* Environment pointer */
-	pushl %ebx       /* Argument pointer */
-	pushl %ecx      /* And the argument count */
+	/* Push .init and .fini arguments to __uClibc_start_main() on the stack */
+	pushl $_fini
+	pushl $_init
 
-#if 0
-	/* Make sure we are not using iBCS2 personality. (i.e. force linux).  */
-	movl $136,%eax
-	sub %ebx,%ebx
-	int $0x80
-#endif
+	/* Push envp, argc, and argc arguments to __uClibc_start_main() on the stack */ 
+	pushl %eax	/* Environment pointer */
+	pushl %ebx	/* Argument pointer */
+	pushl %ecx	/* And the argument count */
 
 	/* Ok, now run uClibc's main() -- shouldn't return */
-	call __uClibc_main
+	call __uClibc_start_main
+
 	/* Crash if somehow `exit' returns anyways.  */
 	hlt
 
diff --git a/libc/sysdeps/linux/mips/crt0.S b/libc/sysdeps/linux/mips/crt0.S
index 6770ab0b1..7ff3b253f 100644
--- a/libc/sysdeps/linux/mips/crt0.S
+++ b/libc/sysdeps/linux/mips/crt0.S
@@ -30,9 +30,22 @@ __start:
 	addu a2, a0, 1	    /* load envp */
         sll  a2, a2, 2
 	add  a2, a2, a1
+
+	/* Store the address of _init in a3 as an argument to __uClibc_start_main() */
+	la   a3, _init
+
+	/* Push _fini onto the stack as the final argument to __uClibc_start_main()
+	    I don't think I am doing this properly but it at least compiles... 
+	*/
+	la   t0, _fini
+	sw   t0,16(sp)
+	
 	/* Ok, now run uClibc's main() -- shouldn't return */
-	jal	__uClibc_main
-	hlt:    b hlt                   /* Crash if somehow it does return.  */
+	jal  __uClibc_start_main
+
+	/* Crash if somehow `exit' returns anyways.  */
+hlt:
+	b   hlt
 
 /* Stick in a dummy reference to main(), so that if an application
  * is linking when the main() function is in a static library (.a)
diff --git a/libc/sysdeps/linux/sh/crt0.S b/libc/sysdeps/linux/sh/crt0.S
index 10915d545..e74ae86c4 100644
--- a/libc/sysdeps/linux/sh/crt0.S
+++ b/libc/sysdeps/linux/sh/crt0.S
@@ -26,13 +26,6 @@
 
 	At this entry point, most registers' values are unspecified, except:
 
-   r4		Contains a function pointer to be registered with `atexit'.
-   		This is how the dynamic linker arranges to have DT_FINI
-		functions called for shared libraries that have been loaded
-		before this code runs.
-		WARNING: At that stage only static linker is supported. For
-		uCLinux we won't bother with r4.
-
    sp		The stack contains the arguments and environment:
    		0(sp)			argc
 		4(sp)			argv[0]
@@ -42,18 +35,26 @@
 		...
 					NULL
 */
+	.file "crt0.S"
 	.text
 	.globl _start
 	.type _start,@function
 	.size _start,_start_end - _start
 _start:
-	/* Clear the frame pointer since this is the outermost frame. (in delay slot) */
+	/* Clear the frame pointer since this is the outermost frame. */
 	mov #0, r14
 
 	/* Pop argc off the stack and save a pointer to argv */
 	mov.l @r15+,r4
 	mov r15, r5
 
+	/* Push the finip argument to __uClibc_start_main() onto the stack */
+	mov.l L_fini,r6
+	mov.l r6,@-r15
+
+	/* Setup the value for the initp argument */
+	mov.l L_init, r7
+
 	/*
 	 * Setup the value for the environment pointer:
 	 * r6 = (argc + 1) * 4
@@ -62,27 +63,39 @@ _start:
 	mov r4,r6
 	add #1,r6
 	shll2 r6
-	add r5,r6
 
-	/* call main */
+	/* jump to __uClibc_start_main (argc, argv, envp, app_init, app_fini) */
 	mov.l L_main, r0
 	jsr @r0
-	nop /* delay slot */
-
+	add r5, r6  /* delay slot */
 	/* We should not get here. */
 	mov.l L_abort, r0
-	jsr @r0
-	nop /* delay slot */
+	jmp @r0
+	nop
 
 _start_end:	
 	.align	2
 
+	.weak   _init
+	.type   _init,@function
+_init:
+	rts
+	nop
+
+.Lfe1:
+	.size   _init,.Lfe1-_init
+	.weak   _fini
+	.set    _fini,_init
 
 L_main:
-	.long	__uClibc_main
+	.long   __uClibc_start_main /* in libuClibc.*.so */
 
-L_abort:
-	.long	abort
+L_init:
+      .long   _init
+L_fini:
+      .long   _fini
+L_abort: 
+      .long   abort   
 
 /* Stick in a dummy reference to main(), so that if an application
  * is linking when the main() function is in a static library (.a)
@@ -90,5 +103,3 @@ L_abort:
 L_dummy_main_reference:
 	.long	main
 
-	.data
-