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-rw-r--r--libc/Android.mk8
-rw-r--r--libc/arch-arm/bionic/crtbegin.c30
-rwxr-xr-xlibc/arch-x86/bionic/crtbegin.c29
-rw-r--r--libc/bionic/getauxval.cpp8
-rw-r--r--libc/bionic/libc_init_common.cpp (renamed from libc/bionic/libc_init_common.c)50
-rw-r--r--libc/bionic/libc_init_common.h29
-rw-r--r--libc/bionic/libc_init_dynamic.c127
-rw-r--r--libc/bionic/libc_init_dynamic.cpp115
-rw-r--r--libc/bionic/libc_init_static.cpp (renamed from libc/bionic/libc_init_static.c)105
-rw-r--r--libc/private/KernelArgumentBlock.h76
-rw-r--r--libc/private/bionic_tls.h2
-rw-r--r--libc/stdlib/atexit.h4
-rwxr-xr-xlinker/arch/x86/begin.c15
-rwxr-xr-xlinker/linker.cpp157
-rw-r--r--linker/linker_environ.cpp37
-rw-r--r--linker/linker_environ.h10
16 files changed, 384 insertions, 418 deletions
diff --git a/libc/Android.mk b/libc/Android.mk
index 301be37..c7828cf 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -177,7 +177,6 @@ libc_common_src_files := \
bionic/isatty.c \
bionic/issetugid.c \
bionic/ldexp.c \
- bionic/libc_init_common.c \
bionic/logd_write.c \
bionic/lseek64.c \
bionic/md5.c \
@@ -275,6 +274,7 @@ libc_bionic_src_files := \
bionic/__fgets_chk.cpp \
bionic/getauxval.cpp \
bionic/getcwd.cpp \
+ bionic/libc_init_common.cpp \
bionic/libgen.cpp \
bionic/__memcpy_chk.cpp \
bionic/__memmove_chk.cpp \
@@ -824,7 +824,7 @@ include $(CLEAR_VARS)
LOCAL_SRC_FILES := \
$(libc_arch_static_src_files) \
$(libc_static_common_src_files) \
- bionic/libc_init_static.c
+ bionic/libc_init_static.cpp
LOCAL_C_INCLUDES := $(libc_common_c_includes)
LOCAL_CFLAGS := $(libc_common_cflags) \
@@ -849,7 +849,7 @@ LOCAL_SRC_FILES := \
$(libc_static_common_src_files) \
bionic/dlmalloc.c \
bionic/malloc_debug_common.cpp \
- bionic/libc_init_static.c
+ bionic/libc_init_static.cpp
LOCAL_CFLAGS := $(libc_common_cflags) \
-DLIBC_STATIC \
@@ -883,7 +883,7 @@ LOCAL_SRC_FILES := \
bionic/dlmalloc.c \
bionic/malloc_debug_common.cpp \
bionic/pthread_debug.cpp \
- bionic/libc_init_dynamic.c
+ bionic/libc_init_dynamic.cpp
ifeq ($(TARGET_ARCH),arm)
LOCAL_NO_CRT := true
diff --git a/libc/arch-arm/bionic/crtbegin.c b/libc/arch-arm/bionic/crtbegin.c
index 0e2d31e..cc58797 100644
--- a/libc/arch-arm/bionic/crtbegin.c
+++ b/libc/arch-arm/bionic/crtbegin.c
@@ -26,21 +26,8 @@
* SUCH DAMAGE.
*/
-typedef struct
-{
- void (**preinit_array)(void);
- void (**init_array)(void);
- void (**fini_array)(void);
-} structors_array_t;
-
-extern int main(int argc, char **argv, char **env);
-
-extern void __libc_init(
- unsigned int *elfdata,
- void (*onexit)(void),
- int (*slingshot)(int, char**, char**),
- structors_array_t const * const structors
-);
+#include "../../bionic/libc_init_common.h"
+#include <stddef.h>
__attribute__ ((section (".preinit_array")))
void (*__PREINIT_ARRAY__)(void) = (void (*)(void)) -1;
@@ -51,17 +38,14 @@ void (*__INIT_ARRAY__)(void) = (void (*)(void)) -1;
__attribute__ ((section (".fini_array")))
void (*__FINI_ARRAY__)(void) = (void (*)(void)) -1;
-__attribute__((visibility("hidden")))
-void _start() {
+__LIBC_HIDDEN__ void _start() {
structors_array_t array;
- void *elfdata;
-
array.preinit_array = &__PREINIT_ARRAY__;
- array.init_array = &__INIT_ARRAY__;
- array.fini_array = &__FINI_ARRAY__;
+ array.init_array = &__INIT_ARRAY__;
+ array.fini_array = &__FINI_ARRAY__;
- elfdata = __builtin_frame_address(0) + sizeof(void *);
- __libc_init(elfdata, (void *) 0, &main, &array);
+ void* raw_args = __builtin_frame_address(0) + sizeof(void*);
+ __libc_init(raw_args, NULL, &main, &array);
}
#include "__dso_handle.h"
diff --git a/libc/arch-x86/bionic/crtbegin.c b/libc/arch-x86/bionic/crtbegin.c
index 5106d9e..63e58a6 100755
--- a/libc/arch-x86/bionic/crtbegin.c
+++ b/libc/arch-x86/bionic/crtbegin.c
@@ -26,21 +26,8 @@
* SUCH DAMAGE.
*/
-typedef struct
-{
- void (**preinit_array)(void);
- void (**init_array)(void);
- void (**fini_array)(void);
-} structors_array_t;
-
-extern int main(int argc, char **argv, char **env);
-
-extern void __libc_init(
- unsigned int *elfdata,
- void (*onexit)(void),
- int (*slingshot)(int, char**, char**),
- structors_array_t const * const structors
-);
+#include "../../bionic/libc_init_common.h"
+#include <stddef.h>
__attribute__ ((section (".preinit_array")))
void (*__PREINIT_ARRAY__)(void) = (void (*)(void)) -1;
@@ -51,18 +38,16 @@ void (*__INIT_ARRAY__)(void) = (void (*)(void)) -1;
__attribute__ ((section (".fini_array")))
void (*__FINI_ARRAY__)(void) = (void (*)(void)) -1;
-__attribute__((visibility("hidden")))
+__LIBC_HIDDEN__
__attribute__((force_align_arg_pointer))
void _start() {
structors_array_t array;
- void *elfdata;
-
array.preinit_array = &__PREINIT_ARRAY__;
- array.init_array = &__INIT_ARRAY__;
- array.fini_array = &__FINI_ARRAY__;
+ array.init_array = &__INIT_ARRAY__;
+ array.fini_array = &__FINI_ARRAY__;
- elfdata = __builtin_frame_address(0) + sizeof(void *);
- __libc_init(elfdata, (void *) 0, &main, &array);
+ void* raw_args = __builtin_frame_address(0) + sizeof(void*);
+ __libc_init(raw_args, NULL, &main, &array);
}
#include "__dso_handle.h"
diff --git a/libc/bionic/getauxval.cpp b/libc/bionic/getauxval.cpp
index 38a05fc..fd225e0 100644
--- a/libc/bionic/getauxval.cpp
+++ b/libc/bionic/getauxval.cpp
@@ -32,17 +32,13 @@
#include <private/bionic_auxv.h>
#include <elf.h>
-__LIBC_HIDDEN__
-Elf32_auxv_t* __libc_auxv = NULL;
+__LIBC_HIDDEN__ Elf32_auxv_t* __libc_auxv = NULL;
extern "C" unsigned long int getauxval(unsigned long int type) {
- Elf32_auxv_t* v;
-
- for (v = __libc_auxv; v->a_type != AT_NULL; v++) {
+ for (Elf32_auxv_t* v = __libc_auxv; v->a_type != AT_NULL; ++v) {
if (v->a_type == type) {
return v->a_un.a_val;
}
}
-
return 0;
}
diff --git a/libc/bionic/libc_init_common.c b/libc/bionic/libc_init_common.cpp
index 86e1eb5..6b4ae2c 100644
--- a/libc/bionic/libc_init_common.c
+++ b/libc/bionic/libc_init_common.cpp
@@ -30,29 +30,31 @@
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
+#include <unistd.h>
#include <elf.h>
#include <asm/page.h>
#include "pthread_internal.h"
#include "atexit.h"
+#include "KernelArgumentBlock.h"
#include "libc_init_common.h"
#include <bionic_tls.h>
#include <errno.h>
#include <private/bionic_auxv.h>
-extern unsigned __get_sp(void);
-extern pid_t gettid(void);
+extern "C" unsigned __get_sp(void);
+extern "C" int __system_properties_init(void);
-char* __progname;
+// Not public, but well-known in the BSDs.
+char* __progname;
+
+// Declared in <unistd.h>
char** environ;
-/* from asm/page.h */
+// Declared in <asm/page.h>.
unsigned int __page_size = PAGE_SIZE;
unsigned int __page_shift = PAGE_SHIFT;
-
-int __system_properties_init(void);
-
/* Init TLS for the initial thread. Called by the linker _before_ libc is mapped
* in memory. Beware: all writes to libc globals from this function will
* apply to linker-private copies and will not be visible from libc later on.
@@ -61,10 +63,10 @@ int __system_properties_init(void);
* stores the pointer in TLS, but does not add it to pthread's gThreadList. This
* has to be done later from libc itself (see __libc_init_common).
*
- * This function also stores the elf_data argument in a specific TLS slot to be later
+ * This function also stores a pointer to the kernel argument block in a TLS slot to be
* picked up by the libc constructor.
*/
-void __libc_init_tls(unsigned** elf_data) {
+extern "C" void __libc_init_tls(void* kernel_argument_block) {
unsigned stack_top = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
unsigned stack_size = 128 * 1024;
unsigned stack_bottom = stack_top - stack_size;
@@ -78,33 +80,21 @@ void __libc_init_tls(unsigned** elf_data) {
static void* tls_area[BIONIC_TLS_SLOTS];
__init_tls(tls_area, &thread);
- tls_area[TLS_SLOT_BIONIC_PREINIT] = elf_data;
+ tls_area[TLS_SLOT_BIONIC_PREINIT] = kernel_argument_block;
}
-void __libc_init_common(uintptr_t* elf_data) {
- int argc = *elf_data;
- char** argv = (char**) (elf_data + 1);
- char** envp = argv + argc + 1;
+void __libc_init_common(KernelArgumentBlock& args) {
+ // Initialize various globals.
+ environ = args.envp;
+ errno = 0;
+ __libc_auxv = args.auxv;
+ __progname = args.argv[0] ? args.argv[0] : const_cast<char*>("<unknown>");
// Get the main thread from TLS and add it to the thread list.
pthread_internal_t* main_thread = __get_thread();
main_thread->allocated_on_heap = false;
_pthread_internal_add(main_thread);
- // Set various globals.
- errno = 0;
- __progname = argv[0] ? argv[0] : "<unknown>";
- environ = envp;
-
- // The auxiliary vector is at the end of the environment block
- while(*envp != NULL) {
- envp++;
- }
- /* The end of the environment block is marked by two NULL pointers */
- envp++;
-
- __libc_auxv = (Elf32_auxv_t*) envp;
-
__system_properties_init(); // Requires 'environ'.
}
@@ -116,7 +106,7 @@ void __libc_init_common(uintptr_t* elf_data) {
* entry in the list has value -1, the last one has value 0.
*/
void __libc_fini(void* array) {
- void** fini_array = array;
+ void** fini_array = reinterpret_cast<void**>(array);
const size_t minus1 = ~(size_t)0; /* ensure proper sign extension */
/* Sanity check - first entry must be -1 */
@@ -135,7 +125,7 @@ void __libc_fini(void* array) {
/* Now call each destructor in reverse order. */
while (count > 0) {
- void (*func)() = (void (*)) fini_array[--count];
+ void (*func)() = (void (*)()) fini_array[--count];
/* Sanity check, any -1 in the list is ignored */
if ((size_t)func == minus1) {
diff --git a/libc/bionic/libc_init_common.h b/libc/bionic/libc_init_common.h
index c55594b..23ac305 100644
--- a/libc/bionic/libc_init_common.h
+++ b/libc/bionic/libc_init_common.h
@@ -28,16 +28,29 @@
#ifndef LIBC_INIT_COMMON_H
#define LIBC_INIT_COMMON_H
-#include <stdint.h>
+#include <sys/cdefs.h>
-typedef struct
-{
- void (**preinit_array)(void);
- void (**init_array)(void);
- void (**fini_array)(void);
+typedef struct {
+ void (**preinit_array)(void);
+ void (**init_array)(void);
+ void (**fini_array)(void);
} structors_array_t;
-extern void __libc_init_common(uintptr_t *elfdata);
-extern void __libc_fini(void* finit_array);
+__BEGIN_DECLS
+
+extern int main(int argc, char** argv, char** env);
+
+__noreturn void __libc_init(void* raw_args,
+ void (*onexit)(void),
+ int (*slingshot)(int, char**, char**),
+ structors_array_t const * const structors);
+void __libc_fini(void* finit_array);
+
+__END_DECLS
+
+#if defined(__cplusplus)
+struct KernelArgumentBlock;
+void __libc_init_common(KernelArgumentBlock& args);
+#endif
#endif
diff --git a/libc/bionic/libc_init_dynamic.c b/libc/bionic/libc_init_dynamic.c
deleted file mode 100644
index 3a7e8e2..0000000
--- a/libc/bionic/libc_init_dynamic.c
+++ /dev/null
@@ -1,127 +0,0 @@
-/*
- * Copyright (C) 2008 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.
- */
-/*
- * libc_init_dynamic.c
- *
- * This source files provides two important functions for dynamic
- * executables:
- *
- * - a C runtime initializer (__libc_preinit), which is called by
- * the dynamic linker when libc.so is loaded. This happens before
- * any other initializer (e.g. static C++ constructors in other
- * shared libraries the program depends on).
- *
- * - a program launch function (__libc_init), which is called after
- * all dynamic linking has been performed. Technically, it is called
- * from arch-$ARCH/bionic/crtbegin_dynamic.S which is itself called
- * by the dynamic linker after all libraries have been loaded and
- * initialized.
- */
-
-#include <stddef.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <elf.h>
-#include "atexit.h"
-#include "libc_init_common.h"
-#include <bionic_tls.h>
-
-/* We flag the __libc_preinit function as a constructor to ensure
- * that its address is listed in libc.so's .init_array section.
- * This ensures that the function is called by the dynamic linker
- * as soon as the shared library is loaded.
- */
-void __attribute__((constructor)) __libc_preinit(void);
-
-void __libc_preinit(void)
-{
- /* Read the ELF data pointer from a special slot of the
- * TLS area, then call __libc_init_common with it.
- *
- * Note that:
- * - we clear the slot so no other initializer sees its value.
- * - __libc_init_common() will change the TLS area so the old one
- * won't be accessible anyway.
- */
- void** tls_area = (void**)__get_tls();
- unsigned* elfdata = tls_area[TLS_SLOT_BIONIC_PREINIT];
-
- tls_area[TLS_SLOT_BIONIC_PREINIT] = NULL;
-
- __libc_init_common(elfdata);
-
- /* Setup pthread routines accordingly to the environment.
- * Requires system properties
- */
- extern void pthread_debug_init(void);
- pthread_debug_init();
-
- /* Setup malloc routines accordingly to the environment.
- * Requires system properties
- */
- extern void malloc_debug_init(void);
- malloc_debug_init();
-}
-
-void __libc_postfini(void)
-{
- extern void malloc_debug_fini(void);
- malloc_debug_fini();
-}
-
-/* This function is called from the executable's _start entry point
- * (see arch-$ARCH/bionic/crtbegin_dynamic.S), which is itself
- * called by the dynamic linker after it has loaded all shared
- * libraries the executable depends on.
- *
- * Note that the dynamic linker has also run all constructors in the
- * executable at this point.
- */
-__noreturn void __libc_init(uintptr_t *elfdata,
- void (*onexit)(void),
- int (*slingshot)(int, char**, char**),
- structors_array_t const * const structors)
-{
- int argc = (int)*elfdata;
- char** argv = (char**)(elfdata + 1);
- char** envp = argv + argc + 1;
-
- /* Several Linux ABIs don't pass the onexit pointer, and the ones that
- * do never use it. Therefore, we ignore it.
- */
-
- /* The executable may have its own destructors listed in its .fini_array
- * so we need to ensure that these are called when the program exits
- * normally.
- */
- if (structors->fini_array)
- __cxa_atexit(__libc_fini,structors->fini_array,NULL);
-
- exit(slingshot(argc, argv, envp));
-}
diff --git a/libc/bionic/libc_init_dynamic.cpp b/libc/bionic/libc_init_dynamic.cpp
new file mode 100644
index 0000000..af03fb0
--- /dev/null
+++ b/libc/bionic/libc_init_dynamic.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+/*
+ * libc_init_dynamic.c
+ *
+ * This source files provides two important functions for dynamic
+ * executables:
+ *
+ * - a C runtime initializer (__libc_preinit), which is called by
+ * the dynamic linker when libc.so is loaded. This happens before
+ * any other initializer (e.g. static C++ constructors in other
+ * shared libraries the program depends on).
+ *
+ * - a program launch function (__libc_init), which is called after
+ * all dynamic linking has been performed. Technically, it is called
+ * from arch-$ARCH/bionic/crtbegin_dynamic.S which is itself called
+ * by the dynamic linker after all libraries have been loaded and
+ * initialized.
+ */
+
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <elf.h>
+#include "atexit.h"
+#include "KernelArgumentBlock.h"
+#include "libc_init_common.h"
+#include <bionic_tls.h>
+
+extern "C" {
+ extern void pthread_debug_init(void);
+ extern void malloc_debug_init(void);
+ extern void malloc_debug_fini(void);
+};
+
+// We flag the __libc_preinit function as a constructor to ensure
+// that its address is listed in libc.so's .init_array section.
+// This ensures that the function is called by the dynamic linker
+// as soon as the shared library is loaded.
+void __attribute__((constructor)) __libc_preinit(void);
+
+void __libc_preinit() {
+ // Read the kernel argument block pointer from TLS.
+ void* tls = const_cast<void*>(__get_tls());
+ KernelArgumentBlock** args_slot = &reinterpret_cast<KernelArgumentBlock**>(tls)[TLS_SLOT_BIONIC_PREINIT];
+ KernelArgumentBlock* args = *args_slot;
+
+ // Clear the slot so no other initializer sees its value.
+ // __libc_init_common() will change the TLS area so the old one won't be accessible anyway.
+ *args_slot = NULL;
+
+ __libc_init_common(*args);
+
+ // Hooks for the debug malloc and pthread libraries to let them know that we're starting up.
+ pthread_debug_init();
+ malloc_debug_init();
+}
+
+void __libc_postfini() {
+ // A hook for the debug malloc library to let it know that we're shutting down.
+ malloc_debug_fini();
+}
+
+// This function is called from the executable's _start entry point
+// (see arch-$ARCH/bionic/crtbegin_dynamic.S), which is itself
+// called by the dynamic linker after it has loaded all shared
+// libraries the executable depends on.
+//
+// Note that the dynamic linker has also run all constructors in the
+// executable at this point.
+__noreturn void __libc_init(void* raw_args,
+ void (*onexit)(void),
+ int (*slingshot)(int, char**, char**),
+ structors_array_t const * const structors) {
+
+ KernelArgumentBlock args(raw_args);
+
+ // Several Linux ABIs don't pass the onexit pointer, and the ones that
+ // do never use it. Therefore, we ignore it.
+
+ // The executable may have its own destructors listed in its .fini_array
+ // so we need to ensure that these are called when the program exits
+ // normally.
+ if (structors->fini_array) {
+ __cxa_atexit(__libc_fini,structors->fini_array,NULL);
+ }
+
+ exit(slingshot(args.argc, args.argv, args.envp));
+}
diff --git a/libc/bionic/libc_init_static.c b/libc/bionic/libc_init_static.cpp
index 24a4397..e5506d1 100644
--- a/libc/bionic/libc_init_static.c
+++ b/libc/bionic/libc_init_static.cpp
@@ -37,19 +37,20 @@
* arrays that must be run before the program's 'main' routine is launched.
*/
+#include <elf.h>
+#include <errno.h>
#include <stddef.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
-#include <stdint.h>
-#include <elf.h>
-#include "pthread_internal.h"
+#include <sys/auxv.h>
+#include <sys/mman.h>
+
#include "atexit.h"
+#include "bionic_tls.h"
+#include "KernelArgumentBlock.h"
#include "libc_init_common.h"
-
-#include <bionic_tls.h>
-#include <errno.h>
-#include <sys/mman.h>
-#include <sys/auxv.h>
+#include "pthread_internal.h"
// Returns the address of the page containing address 'x'.
#define PAGE_START(x) ((x) & PAGE_MASK)
@@ -58,71 +59,53 @@
// itself at the start of a page.
#define PAGE_END(x) PAGE_START((x) + (PAGE_SIZE-1))
-static void call_array(void(**list)())
-{
- // First element is -1, list is null-terminated
- while (*++list) {
- (*list)();
- }
+static void call_array(void(**list)()) {
+ // First element is -1, list is null-terminated
+ while (*++list) {
+ (*list)();
+ }
}
static void apply_gnu_relro() {
- Elf32_Phdr *phdr_start;
- unsigned long int phdr_ct;
- Elf32_Phdr *phdr;
-
- phdr_start = (Elf32_Phdr *) getauxval(AT_PHDR);
- phdr_ct = getauxval(AT_PHNUM);
+ Elf32_Phdr* phdr_start = reinterpret_cast<Elf32_Phdr*>(getauxval(AT_PHDR));
+ unsigned long int phdr_ct = getauxval(AT_PHNUM);
- for (phdr = phdr_start; phdr < (phdr_start + phdr_ct); phdr++) {
- if (phdr->p_type != PT_GNU_RELRO)
- continue;
-
- Elf32_Addr seg_page_start = PAGE_START(phdr->p_vaddr);
- Elf32_Addr seg_page_end = PAGE_END(phdr->p_vaddr + phdr->p_memsz);
-
- // Check return value here? What do we do if we fail?
- mprotect((void *) seg_page_start,
- seg_page_end - seg_page_start,
- PROT_READ);
+ for (Elf32_Phdr* phdr = phdr_start; phdr < (phdr_start + phdr_ct); phdr++) {
+ if (phdr->p_type != PT_GNU_RELRO) {
+ continue;
}
-}
-__noreturn void __libc_init(uintptr_t *elfdata,
- void (*onexit)(void),
- int (*slingshot)(int, char**, char**),
- structors_array_t const * const structors)
-{
- int argc;
- char **argv, **envp;
+ Elf32_Addr seg_page_start = PAGE_START(phdr->p_vaddr);
+ Elf32_Addr seg_page_end = PAGE_END(phdr->p_vaddr + phdr->p_memsz);
- __libc_init_tls(NULL);
-
- /* Initialize the C runtime environment */
- __libc_init_common(elfdata);
+ // Check return value here? What do we do if we fail?
+ mprotect(reinterpret_cast<void*>(seg_page_start), seg_page_end - seg_page_start, PROT_READ);
+ }
+}
- apply_gnu_relro();
+__noreturn void __libc_init(void* raw_args,
+ void (*onexit)(void),
+ int (*slingshot)(int, char**, char**),
+ structors_array_t const * const structors) {
+ __libc_init_tls(NULL);
- /* Several Linux ABIs don't pass the onexit pointer, and the ones that
- * do never use it. Therefore, we ignore it.
- */
+ KernelArgumentBlock args(raw_args);
+ __libc_init_common(args);
- /* pre-init array. */
- call_array(structors->preinit_array);
+ apply_gnu_relro();
- // call static constructors
- call_array(structors->init_array);
+ // Several Linux ABIs don't pass the onexit pointer, and the ones that
+ // do never use it. Therefore, we ignore it.
- argc = (int) *elfdata;
- argv = (char**)(elfdata + 1);
- envp = argv + argc + 1;
+ call_array(structors->preinit_array);
+ call_array(structors->init_array);
- /* The executable may have its own destructors listed in its .fini_array
- * so we need to ensure that these are called when the program exits
- * normally.
- */
- if (structors->fini_array)
- __cxa_atexit(__libc_fini,structors->fini_array,NULL);
+ // The executable may have its own destructors listed in its .fini_array
+ // so we need to ensure that these are called when the program exits
+ // normally.
+ if (structors->fini_array != NULL) {
+ __cxa_atexit(__libc_fini,structors->fini_array,NULL);
+ }
- exit(slingshot(argc, argv, envp));
+ exit(slingshot(args.argc, args.argv, args.envp));
}
diff --git a/libc/private/KernelArgumentBlock.h b/libc/private/KernelArgumentBlock.h
new file mode 100644
index 0000000..d777267
--- /dev/null
+++ b/libc/private/KernelArgumentBlock.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef KERNEL_ARGUMENT_BLOCK_H
+#define KERNEL_ARGUMENT_BLOCK_H
+
+#include <elf.h>
+#include <stdint.h>
+#include <sys/auxv.h>
+
+// When the kernel starts the dynamic linker, it passes a pointer to a block
+// of memory containing argc, the argv array, the environment variable array,
+// and the array of ELF aux vectors. This class breaks that block up into its
+// constituents for easy access.
+class KernelArgumentBlock {
+ public:
+ KernelArgumentBlock(void* raw_args) {
+ uint32_t* args = reinterpret_cast<uint32_t*>(raw_args);
+ argc = static_cast<int>(*args);
+ argv = reinterpret_cast<char**>(args + 1);
+ envp = argv + argc + 1;
+
+ // Skip over all environment variable definitions to find aux vector.
+ // The end of the environment block is marked by two NULL pointers.
+ char** p = envp;
+ while (*p != NULL) {
+ ++p;
+ }
+ ++p; // Skip second NULL;
+
+ auxv = reinterpret_cast<Elf32_auxv_t*>(p);
+ }
+
+ // Similar to ::getauxval but doesn't require the libc global variables to be set up,
+ // so it's safe to call this really early on. This function also lets you distinguish
+ // between the inability to find the given type and its value just happening to be 0.
+ unsigned long getauxval(unsigned long type, bool* found_match = NULL) {
+ for (Elf32_auxv_t* v = auxv; v->a_type != AT_NULL; ++v) {
+ if (v->a_type == type) {
+ if (found_match != NULL) {
+ *found_match = true;
+ }
+ return v->a_un.a_val;
+ }
+ }
+ if (found_match != NULL) {
+ *found_match = false;
+ }
+ return 0;
+ }
+
+ int argc;
+ char** argv;
+ char** envp;
+ Elf32_auxv_t* auxv;
+
+ private:
+ // Disallow copy and assignment.
+ KernelArgumentBlock(const KernelArgumentBlock&);
+ void operator=(const KernelArgumentBlock&);
+};
+
+#endif // KERNEL_ARGUMENT_BLOCK_H
diff --git a/libc/private/bionic_tls.h b/libc/private/bionic_tls.h
index f661ccf..920f506 100644
--- a/libc/private/bionic_tls.h
+++ b/libc/private/bionic_tls.h
@@ -134,7 +134,7 @@ extern void* __get_tls( void );
extern void* __get_stack_base(int *p_stack_size);
/* Initialize the TLS. */
-extern void __libc_init_tls(unsigned** elfdata);
+extern void __libc_init_tls(void* kernel_argument_block);
__END_DECLS
diff --git a/libc/stdlib/atexit.h b/libc/stdlib/atexit.h
index 1b23565..39df2e1 100644
--- a/libc/stdlib/atexit.h
+++ b/libc/stdlib/atexit.h
@@ -44,8 +44,12 @@ struct atexit {
} fns[1]; /* the table itself */
};
+__BEGIN_DECLS
+
extern int __atexit_invalid;
extern struct atexit *__atexit; /* points to head of LIFO stack */
int __cxa_atexit(void (*)(void *), void *, void *);
void __cxa_finalize(void *);
+
+__END_DECLS
diff --git a/linker/arch/x86/begin.c b/linker/arch/x86/begin.c
index 4f3e0ab..cdc98e0 100755
--- a/linker/arch/x86/begin.c
+++ b/linker/arch/x86/begin.c
@@ -26,24 +26,23 @@
* SUCH DAMAGE.
*/
-#include <stdint.h>
+#include <sys/cdefs.h>
-extern unsigned __linker_init(unsigned int *elfdata);
+extern unsigned __linker_init(void* raw_args);
-__attribute__((visibility("hidden")))
-void _start() {
+__LIBC_HIDDEN__ void _start() {
void (*start)(void);
- void* elfdata = (void*) ((uintptr_t) __builtin_frame_address(0) + sizeof(void*));
- start = (void(*)(void))__linker_init(elfdata);
+ void* raw_args = (void*) ((uintptr_t) __builtin_frame_address(0) + sizeof(void*));
+ start = (void(*)(void))__linker_init(raw_args);
/* linker init returns (%eax) the _entry address in the main image */
- /* entry point expects sp to point to elfdata */
+ /* entry point expects sp to point to raw_args */
__asm__ (
"mov %0, %%esp\n\t"
"jmp *%1\n\t"
- : : "r"(elfdata), "r"(start) :
+ : : "r"(raw_args), "r"(start) :
);
/* Unreachable */
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 502035b..77c29a1 100755
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -42,6 +42,7 @@
// Private C library headers.
#include <private/bionic_tls.h>
#include <private/debug_format.h>
+#include <private/KernelArgumentBlock.h>
#include <private/logd.h>
#include <private/ScopedPthreadMutexLocker.h>
@@ -1771,15 +1772,8 @@ static bool soinfo_link_image(soinfo* si) {
* fixed it's own GOT. It is safe to make references to externs
* and other non-local data at this point.
*/
-static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linker_base)
-{
- static soinfo linker_soinfo;
-
- int argc = (int) *elfdata;
- char **argv = (char**) (elfdata + 1);
- unsigned *vecs = (unsigned*) (argv + argc + 1);
-
- /* NOTE: we store the elfdata pointer on a special location
+static unsigned __linker_init_post_relocation(KernelArgumentBlock& args, unsigned linker_base) {
+ /* NOTE: we store the args pointer on a special location
* of the temporary TLS area in order to pass it to
* the C Library's runtime initializer.
*
@@ -1787,7 +1781,7 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
* to point to a different location to ensure that no other
* shared library constructor can access it.
*/
- __libc_init_tls(elfdata);
+ __libc_init_tls(&args);
#if TIMING
struct timeval t0, t1;
@@ -1795,7 +1789,7 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
#endif
// Initialize environment functions, and get to the ELF aux vectors table.
- vecs = linker_env_init(vecs);
+ linker_env_init(args);
debugger_init();
@@ -1815,9 +1809,8 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
}
INFO("[ android linker & debugger ]\n");
- DEBUG("elfdata @ 0x%08x\n", (unsigned)elfdata);
- soinfo* si = soinfo_alloc(argv[0]);
+ soinfo* si = soinfo_alloc(args.argv[0]);
if (si == NULL) {
exit(EXIT_FAILURE);
}
@@ -1827,7 +1820,7 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
link_map* map = &(si->linkmap);
map->l_addr = 0;
- map->l_name = argv[0];
+ map->l_name = args.argv[0];
map->l_prev = NULL;
map->l_next = NULL;
@@ -1841,9 +1834,11 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
* Don't use soinfo_alloc(), because the linker shouldn't
* be on the soinfo list.
*/
- strlcpy((char*) linker_soinfo.name, "/system/bin/linker", sizeof linker_soinfo.name);
+ static soinfo linker_soinfo;
+ strlcpy(linker_soinfo.name, "/system/bin/linker", sizeof(linker_soinfo.name));
linker_soinfo.flags = 0;
linker_soinfo.base = linker_base;
+
/*
* Set the dynamic field in the link map otherwise gdb will complain with
* the following:
@@ -1851,42 +1846,29 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
* expected address (wrong library or version mismatch?)
*/
Elf32_Ehdr *elf_hdr = (Elf32_Ehdr *) linker_base;
- Elf32_Phdr *phdr =
- (Elf32_Phdr *)((unsigned char *) linker_base + elf_hdr->e_phoff);
+ Elf32_Phdr *phdr = (Elf32_Phdr*)((unsigned char*) linker_base + elf_hdr->e_phoff);
phdr_table_get_dynamic_section(phdr, elf_hdr->e_phnum, linker_base,
&linker_soinfo.dynamic, NULL, NULL);
insert_soinfo_into_debug_map(&linker_soinfo);
- /* extract information passed from the kernel */
- while (vecs[0] != 0){
- switch(vecs[0]){
- case AT_PHDR:
- si->phdr = (Elf32_Phdr*) vecs[1];
- break;
- case AT_PHNUM:
- si->phnum = (int) vecs[1];
- break;
- case AT_ENTRY:
- si->entry = vecs[1];
- break;
- }
- vecs += 2;
- }
+ // Extract information passed from the kernel.
+ si->phdr = reinterpret_cast<Elf32_Phdr*>(args.getauxval(AT_PHDR));
+ si->phnum = args.getauxval(AT_PHNUM);
+ si->entry = args.getauxval(AT_ENTRY);
/* Compute the value of si->base. We can't rely on the fact that
* the first entry is the PHDR because this will not be true
* for certain executables (e.g. some in the NDK unit test suite)
*/
- int nn;
si->base = 0;
si->size = phdr_table_get_load_size(si->phdr, si->phnum);
si->load_bias = 0;
- for ( nn = 0; nn < si->phnum; nn++ ) {
- if (si->phdr[nn].p_type == PT_PHDR) {
- si->load_bias = (Elf32_Addr)si->phdr - si->phdr[nn].p_vaddr;
- si->base = (Elf32_Addr) si->phdr - si->phdr[nn].p_offset;
- break;
- }
+ for (int i = 0; i < si->phnum; ++i) {
+ if (si->phdr[i].p_type == PT_PHDR) {
+ si->load_bias = reinterpret_cast<Elf32_Addr>(si->phdr) - si->phdr[i].p_vaddr;
+ si->base = reinterpret_cast<Elf32_Addr>(si->phdr) - si->phdr[i].p_offset;
+ break;
+ }
}
si->dynamic = (unsigned *)-1;
si->refcount = 1;
@@ -1920,13 +1902,13 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
#if TIMING
gettimeofday(&t1,NULL);
- PRINT("LINKER TIME: %s: %d microseconds\n", argv[0], (int) (
+ PRINT("LINKER TIME: %s: %d microseconds\n", e.argv[0], (int) (
(((long long)t1.tv_sec * 1000000LL) + (long long)t1.tv_usec) -
(((long long)t0.tv_sec * 1000000LL) + (long long)t0.tv_usec)
));
#endif
#if STATS
- PRINT("RELO STATS: %s: %d abs, %d rel, %d copy, %d symbol\n", argv[0],
+ PRINT("RELO STATS: %s: %d abs, %d rel, %d copy, %d symbol\n", e.argv[0],
linker_stats.count[kRelocAbsolute],
linker_stats.count[kRelocRelative],
linker_stats.count[kRelocCopy],
@@ -1946,7 +1928,7 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
}
}
}
- PRINT("PAGES MODIFIED: %s: %d (%dKB)\n", argv[0], count, count * 4);
+ PRINT("PAGES MODIFIED: %s: %d (%dKB)\n", e.argv[0], count, count * 4);
}
#endif
@@ -1958,31 +1940,6 @@ static unsigned __linker_init_post_relocation(unsigned **elfdata, unsigned linke
return si->entry;
}
-/*
- * Find the value of AT_BASE passed to us by the kernel. This is the load
- * location of the linker.
- */
-static unsigned find_linker_base(unsigned **elfdata) {
- int argc = (int) *elfdata;
- char **argv = (char**) (elfdata + 1);
- unsigned *vecs = (unsigned*) (argv + argc + 1);
- while (vecs[0] != 0) {
- vecs++;
- }
-
- /* The end of the environment block is marked by two NULL pointers */
- vecs++;
-
- while(vecs[0]) {
- if (vecs[0] == AT_BASE) {
- return vecs[1];
- }
- vecs += 2;
- }
-
- return 0; // should never happen
-}
-
/* Compute the load-bias of an existing executable. This shall only
* be used to compute the load bias of an executable or shared library
* that was loaded by the kernel itself.
@@ -2018,39 +1975,41 @@ get_elf_exec_load_bias(const Elf32_Ehdr* elf)
* relocations, any attempt to reference an extern variable, extern
* function, or other GOT reference will generate a segfault.
*/
-extern "C" unsigned __linker_init(unsigned **elfdata) {
- unsigned linker_addr = find_linker_base(elfdata);
- Elf32_Ehdr *elf_hdr = (Elf32_Ehdr *) linker_addr;
- Elf32_Phdr *phdr =
- (Elf32_Phdr *)((unsigned char *) linker_addr + elf_hdr->e_phoff);
-
- soinfo linker_so;
- memset(&linker_so, 0, sizeof(soinfo));
-
- linker_so.base = linker_addr;
- linker_so.size = phdr_table_get_load_size(phdr, elf_hdr->e_phnum);
- linker_so.load_bias = get_elf_exec_load_bias(elf_hdr);
- linker_so.dynamic = (unsigned *) -1;
- linker_so.phdr = phdr;
- linker_so.phnum = elf_hdr->e_phnum;
- linker_so.flags |= FLAG_LINKER;
-
- if (!soinfo_link_image(&linker_so)) {
- // It would be nice to print an error message, but if the linker
- // can't link itself, there's no guarantee that we'll be able to
- // call write() (because it involves a GOT reference).
- //
- // This situation should never occur unless the linker itself
- // is corrupt.
- exit(EXIT_FAILURE);
- }
+extern "C" unsigned __linker_init(void* raw_args) {
+ KernelArgumentBlock args(raw_args);
+
+ unsigned linker_addr = args.getauxval(AT_BASE);
+
+ Elf32_Ehdr *elf_hdr = (Elf32_Ehdr*) linker_addr;
+ Elf32_Phdr *phdr = (Elf32_Phdr*)((unsigned char*) linker_addr + elf_hdr->e_phoff);
+
+ soinfo linker_so;
+ memset(&linker_so, 0, sizeof(soinfo));
+
+ linker_so.base = linker_addr;
+ linker_so.size = phdr_table_get_load_size(phdr, elf_hdr->e_phnum);
+ linker_so.load_bias = get_elf_exec_load_bias(elf_hdr);
+ linker_so.dynamic = (unsigned*) -1;
+ linker_so.phdr = phdr;
+ linker_so.phnum = elf_hdr->e_phnum;
+ linker_so.flags |= FLAG_LINKER;
+
+ if (!soinfo_link_image(&linker_so)) {
+ // It would be nice to print an error message, but if the linker
+ // can't link itself, there's no guarantee that we'll be able to
+ // call write() (because it involves a GOT reference).
+ //
+ // This situation should never occur unless the linker itself
+ // is corrupt.
+ exit(EXIT_FAILURE);
+ }
- // We have successfully fixed our own relocations. It's safe to run
- // the main part of the linker now.
- unsigned start_address = __linker_init_post_relocation(elfdata, linker_addr);
+ // We have successfully fixed our own relocations. It's safe to run
+ // the main part of the linker now.
+ unsigned start_address = __linker_init_post_relocation(args, linker_addr);
- set_soinfo_pool_protection(PROT_READ);
+ set_soinfo_pool_protection(PROT_READ);
- // Return the address that the calling assembly stub should jump to.
- return start_address;
+ // Return the address that the calling assembly stub should jump to.
+ return start_address;
}
diff --git a/linker/linker_environ.cpp b/linker/linker_environ.cpp
index 8ae5a9d..edc659a 100644
--- a/linker/linker_environ.cpp
+++ b/linker/linker_environ.cpp
@@ -33,6 +33,8 @@
#include <stdlib.h>
#include <unistd.h>
+#include <private/KernelArgumentBlock.h>
+
static char** _envp;
static bool _AT_SECURE_value = true;
@@ -40,21 +42,18 @@ bool get_AT_SECURE() {
return _AT_SECURE_value;
}
-static void __init_AT_SECURE(unsigned* auxv) {
+static void __init_AT_SECURE(KernelArgumentBlock& args) {
// Check auxv for AT_SECURE first to see if program is setuid, setgid,
// has file caps, or caused a SELinux/AppArmor domain transition.
- for (unsigned* v = auxv; v[0]; v += 2) {
- if (v[0] == AT_SECURE) {
- // Kernel told us whether to enable secure mode.
- _AT_SECURE_value = v[1];
- return;
- }
- }
+ bool kernel_supplied_AT_SECURE;
+ _AT_SECURE_value = args.getauxval(AT_SECURE, &kernel_supplied_AT_SECURE);
// We don't support ancient kernels.
- const char* msg = "FATAL: kernel did not supply AT_SECURE\n";
- write(2, msg, strlen(msg));
- exit(EXIT_FAILURE);
+ if (!kernel_supplied_AT_SECURE) {
+ const char* msg = "FATAL: kernel did not supply AT_SECURE\n";
+ write(2, msg, strlen(msg));
+ exit(EXIT_FAILURE);
+ }
}
// Check if the environment variable definition at 'envstr'
@@ -164,22 +163,12 @@ static void __sanitize_environment_variables() {
dst[0] = NULL;
}
-unsigned* linker_env_init(unsigned* environment_and_aux_vectors) {
+void linker_env_init(KernelArgumentBlock& args) {
// Store environment pointer - can't be NULL.
- _envp = reinterpret_cast<char**>(environment_and_aux_vectors);
+ _envp = args.envp;
- // Skip over all environment variable definitions.
- // The end of the environment block is marked by two NULL pointers.
- unsigned* aux_vectors = environment_and_aux_vectors;
- while (aux_vectors[0] != 0) {
- ++aux_vectors;
- }
- ++aux_vectors;
-
- __init_AT_SECURE(aux_vectors);
+ __init_AT_SECURE(args);
__sanitize_environment_variables();
-
- return aux_vectors;
}
const char* linker_env_get(const char* name) {
diff --git a/linker/linker_environ.h b/linker/linker_environ.h
index d808728..cd7a65b 100644
--- a/linker/linker_environ.h
+++ b/linker/linker_environ.h
@@ -29,10 +29,10 @@
#ifndef LINKER_ENVIRON_H
#define LINKER_ENVIRON_H
-// Call this function before anything else. 'environment_and_aux_vectors'
-// must point to the environment block in the ELF data block. The function
-// returns the start of the aux vectors after the environment block.
-extern unsigned* linker_env_init(unsigned* environment_and_aux_vectors);
+struct KernelArgumentBlock;
+
+// Call this function before any of the other functions in this header file.
+extern void linker_env_init(KernelArgumentBlock& args);
// Returns the value of environment variable 'name' if defined and not
// empty, or NULL otherwise.
@@ -41,4 +41,4 @@ extern const char* linker_env_get(const char* name);
// Returns the value of this program's AT_SECURE variable.
extern bool get_AT_SECURE();
-#endif /* LINKER_ENVIRON_H */
+#endif // LINKER_ENVIRON_H
generated by cgit v1.1 at 2025-01-08 22:29:32 +0000