From: David 'Digit' Turner Date: Wed, 3 Jun 2009 17:32:37 +0000 (+0200) Subject: Revert "Fix the C library initialization to avoid calling static C++ constructors... X-Git-Tag: android-x86-1.6~14^2~6 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=3a654b1e04d4275ae315cfe1b196998acf10052c;p=android-x86%2Fbionic.git Revert "Fix the C library initialization to avoid calling static C++ constructors twice." This reverts commit 03eabfe65e1e2c36f4d26c78a730fa19a3bdada3. --- diff --git a/libc/arch-arm/bionic/crtbegin_dynamic.S b/libc/arch-arm/bionic/crtbegin_dynamic.S index 624d611fb..e26592317 100644 --- a/libc/arch-arm/bionic/crtbegin_dynamic.S +++ b/libc/arch-arm/bionic/crtbegin_dynamic.S @@ -30,35 +30,25 @@ .type _start,#function .globl _start -# This is the small startup code that is called from -# the dynamic linker to execute an executable once all -# dependent shared libraries have been loaded and -# initialized. +# this is the small startup code that is first run when +# any executable that is statically-linked with Bionic +# runs. # -# It's purpose is to call __libc_init as defined in -# bionic/libc_init_dynamic.c with appropriate +# it's purpose is to call __libc_init with appropriate # arguments, which are: # # - the address of the raw data block setup by the Linux # kernel ELF loader # -# - address of an "onexit" function (not used on any -# platform supported by Bionic) +# - address of an "onexit" function, not used on any +# platform supported by Bionic # # - address of the "main" function of the program. We # can't hard-code it in the adr pseudo instruction # so we use a tiny trampoline that will get relocated # by the dynamic linker before this code runs # -# - address of the constructors table, i.e. a table -# that points to various initialization and -# finalization sections for the program. -# -# NOTE: This code is currently placed in shared libraries -# by the build system, but will be ignored. -# -# On the other hand, the arrays defined below are -# required and will be parsed by the dynamic linker. +# - address of the constructor list # _start: mov r0, sp @@ -73,7 +63,7 @@ _start: .long __INIT_ARRAY__ .long __FINI_ARRAY__ .long __CTOR_LIST__ - + # the .ctors section contains a list of pointers to "constructor" # functions that need to be called in order during C library initialization, # just before the program is being run. This is a C++ requirement diff --git a/libc/arch-arm/bionic/crtbegin_static.S b/libc/arch-arm/bionic/crtbegin_static.S index 69d8df66c..e26592317 100644 --- a/libc/arch-arm/bionic/crtbegin_static.S +++ b/libc/arch-arm/bionic/crtbegin_static.S @@ -30,27 +30,25 @@ .type _start,#function .globl _start -# This is the small startup code that is first run when -# any static executable runs. A static executable is one -# that is started directly by the Linux kernel, not from -# the dynamic linker, it thus cannot depend on any shared -# library. +# this is the small startup code that is first run when +# any executable that is statically-linked with Bionic +# runs. # -# It's purpose is to call __libc_init as defined in -# bionic/libc_init_static.c with appropriate +# it's purpose is to call __libc_init with appropriate # arguments, which are: # # - the address of the raw data block setup by the Linux # kernel ELF loader # -# - address of an "onexit" function (not used on any -# platform supported by Bionic). +# - address of an "onexit" function, not used on any +# platform supported by Bionic # -# - address of the "main" function of the program. +# - address of the "main" function of the program. We +# can't hard-code it in the adr pseudo instruction +# so we use a tiny trampoline that will get relocated +# by the dynamic linker before this code runs # -# - address of the constructors table, i.e. a table -# that points to various initialization and -# finalization sections for the program. +# - address of the constructor list # _start: mov r0, sp @@ -61,18 +59,11 @@ _start: 0: b main -# The "C++ ABI for ARM" document that static C++ constructors -# shall only be called from the .init_array section. -# -# Do we really need a .ctors section on ARM platforms ? -# It looks like it will always be empty. -# - 1: .long __PREINIT_ARRAY__ .long __INIT_ARRAY__ .long __FINI_ARRAY__ .long __CTOR_LIST__ - + # the .ctors section contains a list of pointers to "constructor" # functions that need to be called in order during C library initialization, # just before the program is being run. This is a C++ requirement diff --git a/libc/arch-x86/bionic/crtbegin_dynamic.S b/libc/arch-x86/bionic/crtbegin_dynamic.S index b013641d6..3b47b18ef 100644 --- a/libc/arch-x86/bionic/crtbegin_dynamic.S +++ b/libc/arch-x86/bionic/crtbegin_dynamic.S @@ -29,35 +29,25 @@ .type _start, @function .globl _start -# This is the small startup code that is called from -# the dynamic linker to execute an executable once all -# dependent shared libraries have been loaded and -# initialized. +# this is the small startup code that is first run when +# any executable that is statically-linked with Bionic +# runs. # -# It's purpose is to call __libc_init as defined in -# bionic/libc_init_dynamic.c with appropriate +# it's purpose is to call __libc_init with appropriate # arguments, which are: # # - the address of the raw data block setup by the Linux # kernel ELF loader # -# - address of an "onexit" function (not used on any -# platform supported by Bionic) +# - address of an "onexit" function, not used on any +# platform supported by Bionic # # - address of the "main" function of the program. We # can't hard-code it in the adr pseudo instruction # so we use a tiny trampoline that will get relocated # by the dynamic linker before this code runs # -# - address of the constructors table, i.e. a table -# that points to various initialization and -# finalization sections for the program. -# -# NOTE: This code is currently placed in shared libraries -# by the build system, but will be ignored. -# -# On the other hand, the arrays defined below are -# required and will be parsed by the dynamic linker. +# - address of the constructor list # _start: mov %esp, %eax diff --git a/libc/arch-x86/bionic/crtbegin_static.S b/libc/arch-x86/bionic/crtbegin_static.S index a6c9ebfaf..eb4acee8f 100644 --- a/libc/arch-x86/bionic/crtbegin_static.S +++ b/libc/arch-x86/bionic/crtbegin_static.S @@ -29,27 +29,25 @@ .type _start, @function .globl _start -# This is the small startup code that is first run when -# any static executable runs. A static executable is one -# that is started directly by the Linux kernel, not from -# the dynamic linker, it thus cannot depend on any shared -# library. +# this is the small startup code that is first run when +# any executable that is statically-linked with Bionic +# runs. # -# It's purpose is to call __libc_init as defined in -# bionic/libc_init_static.c with appropriate +# it's purpose is to call __libc_init with appropriate # arguments, which are: # # - the address of the raw data block setup by the Linux # kernel ELF loader # -# - address of an "onexit" function (not used on any -# platform supported by Bionic). +# - address of an "onexit" function, not used on any +# platform supported by Bionic # -# - address of the "main" function of the program. +# - address of the "main" function of the program. We +# can't hard-code it in the adr pseudo instruction +# so we use a tiny trampoline that will get relocated +# by the dynamic linker before this code runs # -# - address of the constructors table, i.e. a table -# that points to various initialization and -# finalization sections for the program. +# - address of the constructor list # _start: mov %esp, %eax diff --git a/libc/bionic/libc_init_common.c b/libc/bionic/libc_init_common.c index 523afcfb2..de4919d27 100644 --- a/libc/bionic/libc_init_common.c +++ b/libc/bionic/libc_init_common.c @@ -39,11 +39,8 @@ #include #include -/* This contains the common C library initialization code. - * To understand what happens here, you should read the - * "Initialization and Finalization" section of the file - * named bionic/linker/README.TXT - */ +extern void _init(void); +extern void _fini(void); static void call_array(void(**list)()) { @@ -53,6 +50,15 @@ static void call_array(void(**list)()) } } +static void __bionic_do_global_dtors(structors_array_t const * const p) +{ + call_array(p->fini_array); + //_fini(); +} + +extern unsigned __get_sp(void); +extern pid_t gettid(void); + char* __progname; char **environ; @@ -63,28 +69,30 @@ unsigned int __page_shift = PAGE_SHIFT; int __system_properties_init(void); -/* This function can be run under two different contexts: - * - * - for statically linked executables (i.e. those who do - * not depend on shared libraries at all), it will be - * called from the __libc_init() function defined in - * bionic/libc_init_static.c - * - * - for dynamic executables, it will be called from the - * __libc_init() function defined in bionic/libc_init_dynamic.c - * - */ void __libc_init_common(uintptr_t *elfdata, void (*onexit)(void), int (*slingshot)(int, char**, char**), structors_array_t const * const structors, void (*pre_ctor_hook)()) { + pthread_internal_t thread; + pthread_attr_t thread_attr; + void *tls_area[BIONIC_TLS_SLOTS]; int argc; char **argv, **envp, **envend; struct auxentry *auxentry; unsigned int page_size = 0, page_shift = 0; + /* The main thread's stack has empirically shown to be 84k */ + unsigned stacktop = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE; + unsigned stacksize = 128 * 1024; //84 * 1024; + unsigned stackbottom = stacktop - stacksize; + + pthread_attr_init(&thread_attr); + pthread_attr_setstack(&thread_attr, (void*)stackbottom, stacksize); + _init_thread(&thread, gettid(), &thread_attr, (void*)stackbottom); + __init_tls(tls_area, &thread); + argc = (int) *elfdata++; argv = (char**) elfdata; envp = argv+(argc+1); @@ -98,17 +106,17 @@ void __libc_init_common(uintptr_t *elfdata, if (pre_ctor_hook) pre_ctor_hook(); - if (structors != NULL) { - // pre-init array. - call_array(structors->preinit_array); + // XXX: we should execute the .fini_array upon exit - // for compatibility with non-eabi binary, call the .ctors section - // this is only useful for static non-ARM (e.g. x86) executables. - call_array(structors->ctors_array); + // pre-init array. + // XXX: I'm not sure what's the different with the init array. + call_array(structors->preinit_array); - // call static constructors - call_array(structors->init_array); - } + // for compatibility with non-eabi binary, call the .ctors section + call_array(structors->ctors_array); + + // call static constructors + call_array(structors->init_array); exit(slingshot(argc, argv, envp)); } diff --git a/libc/bionic/libc_init_dynamic.c b/libc/bionic/libc_init_dynamic.c index e1ff13d86..8cf24b466 100644 --- a/libc/bionic/libc_init_dynamic.c +++ b/libc/bionic/libc_init_dynamic.c @@ -25,29 +25,18 @@ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ - /* * libc_init_static.c * - * This function is called for dynamic executables after the dynamic - * linker has loaded and initialized all dependent shared libraries. - * - * It takes the raw data block set up by the ELF loader - * in the kernel and parses it. + * This function takes the raw data block set up by the ELF loader + * in the kernel and parses it. It is invoked by crt0.S which makes + * any necessary adjustments and passes calls this function using + * the standard C calling convention. * * The arguments are: - * elfdata -- The ELF loader data block; usually from the stack. - * Basically a pointer to argc. - * - * onexit -- Function to call on exit, can be NULL. - * - * slingshot -- Address of the program's main function - * - * structors -- Table of constructor functions arrays that must - * be called before the slingshot. - * - * It is called from the assembly fragment found in - * arch-$ARCH/bionic/crtbegin_dynamic.S + * uintptr_t *elfdata -- The ELF loader data block; usually from the stack. + * Basically a pointer to argc. + * void (*onexit)(void) -- Function to install into onexit */ /* @@ -73,18 +62,5 @@ __noreturn void __libc_init(uintptr_t *elfdata, int (*slingshot)(int, char**, char**), structors_array_t const * const structors) { - /* NOTE: At this point, the dynamic linker has *already* called - * all initializers properly, so we ignore 'structors' to - * avoid calling them twice. - */ - - /* NOTE2: Is it worthwhile to use malloc_debug_init() in the case of - * of the non-debug shared C library ? - * - * The implementation in bionic/malloc_leak.c contains a lot - * of code which will turn to be unused, and we add a dispatch - * overhead to malloc() et al. that proved to be significant - * in the past (e.g. making boot sequence 5% slower) - */ - __libc_init_common(elfdata, onexit, slingshot, NULL, malloc_debug_init); + __libc_init_common(elfdata, onexit, slingshot, structors, malloc_debug_init); } diff --git a/libc/bionic/libc_init_static.c b/libc/bionic/libc_init_static.c index d7af64088..ec463f7ec 100644 --- a/libc/bionic/libc_init_static.c +++ b/libc/bionic/libc_init_static.c @@ -25,30 +25,18 @@ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ - /* * libc_init_static.c * - * This function is called for static executables, i.e. those that - * dont depend on shared libraries and are directly started by the - * Linux kernel. - * - * It takes the raw data block set up by the ELF loader - * in the kernel and parses it. + * This function takes the raw data block set up by the ELF loader + * in the kernel and parses it. It is invoked by crt0.S which makes + * any necessary adjustments and passes calls this function using + * the standard C calling convention. * * The arguments are: - * elfdata -- The ELF loader data block; usually from the stack. - * Basically a pointer to argc. - * - * onexit -- Function to call on exit, can be NULL. - * - * slingshot -- Address of the program's main function - * - * structors -- Table of constructor functions arrays that must - * be called before the slingshot. - * - * It is called from the assembly fragment found in - * arch-$ARCH/bionic/crtbegin_static.S + * uintptr_t *elfdata -- The ELF loader data block; usually from the stack. + * Basically a pointer to argc. + * void (*onexit)(void) -- Function to install into onexit */ /* @@ -63,19 +51,18 @@ #include #include #include -#include "bionic_preinit.h" +#include "pthread_internal.h" +#include "atexit.h" #include "libc_init_common.h" +#include +#include + __noreturn void __libc_init(uintptr_t *elfdata, void (*onexit)(void), int (*slingshot)(int, char**, char**), structors_array_t const * const structors) { - pthread_internal_t thread; - void *tls_area[BIONIC_TLS_SLOTS]; - - __libc_preinit( &thread, tls_area ); - /* * To enable malloc checks for statically linked programs, add * "WITH_MALLOC_CHECK_LIBC_A := true" in device/buildspec.mk diff --git a/libc/private/pthread_internal.h b/libc/bionic/pthread_internal.h similarity index 100% rename from libc/private/pthread_internal.h rename to libc/bionic/pthread_internal.h diff --git a/libc/private/bionic_preinit.h b/libc/private/bionic_preinit.h deleted file mode 100644 index b74a8b4d0..000000000 --- a/libc/private/bionic_preinit.h +++ /dev/null @@ -1,76 +0,0 @@ -/* - * Copyright (C) 2009 The Android Open Source Project - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS - * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE - * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, - * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS - * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED - * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, - * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT - * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - */ - -#ifndef _BIONIC_PREINIT_H -#define _BIONIC_PREINIT_H - -#include "pthread_internal.h" -#include "bionic_tls.h" -#include - -/* this function is used to perform a minimal initialization of the - * the C library. This must be performed before any other call to - * other functions, in either the dynamic linker's startup code - * or libc_init_static.c - * - * 'main_thread' and 'tls_area' must be persistent variables, - * which means they must be either global, or allocated in the - * main thread's stack frame and never, ever, freed before - * program exit. - * - * VERY IMPORTANT NOTE: - * - * THIS IMPLEMENTATION SHOULD NOT USE GLOBAL VARIABLES. - * - * The reason is the dynamic linker's tricky usage of C library - * functions and later renaming of their symbols. See the - * "C Library Usage Restriction" section in bionic/linker/README.TXT - * for details. - */ - -extern unsigned __get_sp(void); -extern pid_t gettid(void); - -static __inline__ void -__libc_preinit( pthread_internal_t* main_thread, - void* tls_area[BIONIC_TLS_SLOTS] ) -{ - pthread_attr_t thread_attr; - - /* Setup the main thread's information */ - unsigned stacktop = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE; - unsigned stacksize = 128 * 1024; - unsigned stackbottom = stacktop - stacksize; - - pthread_attr_init(&thread_attr); - pthread_attr_setstack(&thread_attr, (void*)stackbottom, stacksize); - _init_thread(main_thread, gettid(), &thread_attr, (void*)stackbottom); - __init_tls(tls_area, main_thread); -} - -#endif /* _BIONIC_INIT_H */ diff --git a/linker/README.TXT b/linker/README.TXT index 0be9be45c..4fff14e51 100644 --- a/linker/README.TXT +++ b/linker/README.TXT @@ -112,46 +112,3 @@ On x86, the lists of constructors and destructors are placed in special sections named ".ctors" and ".dtors", and the DT_INIT / DT_FINI functions are in charge of calling them explicitely. - -C Library Usage Restrictions: ------------------------------ - -The dynamic linker executable (/system/bin/linker) is built using the -static version of the C library (libc.a), in order to use various functions -and system calls provided by it. - -However, it will normally, at runtime, map the shared library version -of the C library (/system/lib/libc.so) as well in the process' address -space. This means that: - -- any global variable defined by the C library will appear twice in - the process address space, at different addresses. - -- some functions will be duplicated too, though those that refer to - global variables will refer to distinct addresses. - -This can lead to subtle conflicts, typically for process-specific data that -is managed through the kernel. A good example is the handling of the -end of the data segment, which is normally done through the 'sbrk' or -'brk' system call by the malloc implementation. - -If two similar, but distinct, malloc implementations run at the same time, -and if each one thinks it exclusively manages some process settings, hideous -corruption or crashes may occur. - -For this very reason, THE DYNAMIC LINKER CANNOT USE malloc()/free() ! -That's why it is linked to a special version of the C library that will -abort when any of these functions (or calloc()/realloc()) is called. - -Moreover, it cannot use any C library feature that could use these -indirectly. Experience as shown that this meant: - -- avoiding any FILE* - related stdio function (fopen, fread, fprintf, etc...) -- avoiding snprintf() with any floating-point formatter ("%f", "%g") - -There are probably other cases that haven't been discovered yet, so the -code needs to be very frugal in its use of the C library. - -This also explains why the linker's tracing macros are all disabled by -default. Enabling them sometimes creates problems, depending on the process -being loaded, so they should be considered an experimental feature for now. diff --git a/linker/linker.c b/linker/linker.c index e7d5ab447..e398f8247 100644 --- a/linker/linker.c +++ b/linker/linker.c @@ -44,7 +44,7 @@ #include /* special private C library header - see Android.mk */ -#include +#include #include "linker.h" #include "linker_debug.h" @@ -1691,7 +1691,6 @@ int main(int argc, char **argv) #define ANDROID_TLS_SLOTS BIONIC_TLS_SLOTS static void * __tls_area[ANDROID_TLS_SLOTS]; -static pthread_internal_t __main_thread; unsigned __linker_init(unsigned **elfdata) { @@ -1710,7 +1709,8 @@ unsigned __linker_init(unsigned **elfdata) gettimeofday(&t0, 0); #endif - __libc_preinit(&__main_thread, __tls_area); + __set_tls(__tls_area); + ((unsigned *)__get_tls())[TLS_SLOT_THREAD_ID] = gettid(); debugger_init();