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Implement clone() C library function properly.

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Only provide an implementation for ARM at the moment, since
it requires specific assembly fragments (the standard syscall
stubs cannot be used because the child returns in a different
stack).
This commit is contained in:
David 'Digit' Turner 2010-01-22 18:59:05 -08:00
parent 1a2917ca95
commit 97cf7f3394
15 changed files with 213 additions and 52 deletions
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1
libc/Android.mk
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@ -289,6 +289,7 @@ libc_common_src_files := \
ifeq ($(TARGET_ARCH),arm)
libc_common_src_files += \
bionic/eabi.c \
bionic/bionic_clone.c \
arch-arm/bionic/__get_pc.S \
arch-arm/bionic/__get_sp.S \
arch-arm/bionic/_exit_with_stack_teardown.S \

7
libc/SYSCALLS.TXT
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@ -34,7 +34,12 @@ void _exit_thread:exit (int) 1
pid_t __fork:fork (void) 2
pid_t _waitpid:waitpid (pid_t, int*, int, struct rusage*) -1,7
int waitid(int, pid_t, struct siginfo_t*, int,void*) 280,284
pid_t __clone:clone(int (*fn)(void*), void *child_stack, int flags, void *arg) 120
# NOTE: this system call is never called directly, but we list it there
# to have __NR_clone properly defined.
#
pid_t __sys_clone:clone (int, void*, int*, void*, int*) 120
int execve (const char*, char* const*, char* const*) 11
int setuid:setuid32 (uid_t) 213

110
libc/arch-arm/bionic/clone.S
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@ -1,5 +1,5 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* Copyright (C) 2008-2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -27,48 +27,102 @@
*/
#include <sys/linux-syscalls.h>
.text
.type __pthread_clone, #function
.global __pthread_clone
.align 4
__pthread_clone:
@ insert the args onto the new stack
str r0, [r1, #-4]
str r3, [r1, #-8]
.text
.type __pthread_clone, #function
.global __pthread_clone
.align 4
.fnstart
__pthread_clone:
@ insert the args onto the new stack
str r0, [r1, #-4]
str r3, [r1, #-8]
@ do the system call
@ get flags
@ do the system call
@ get flags
mov r0, r2
@ new sp is already in r1
#if __ARM_EABI__
stmfd sp!, {r4, r7}
ldr r7, =__NR_clone
swi #0
swi #0
#else
swi #__NR_clone
swi #__NR_clone
#endif
movs r0, r0
movs r0, r0
#if __ARM_EABI__
ldmnefd sp!, {r4, r7}
#endif
blt __error
bxne lr
blt __error
bxne lr
@ pick the function arg and call address off the stack and jump
@ to the C __thread_entry function which does some setup and then
@ calls the thread's start function
@ pick the function arg and call address off the stack and jump
@ to the C __thread_entry function which does some setup and then
@ calls the thread's start function
ldr r0, [sp, #-4]
ldr r1, [sp, #-8]
mov r2, sp @ __thread_entry needs the TLS pointer
b __thread_entry
ldr r0, [sp, #-4]
ldr r1, [sp, #-8]
mov r2, sp @ __thread_entry needs the TLS pointer
b __thread_entry
__error:
mov r0, #-1
bx lr
mov r0, #-1
bx lr
.fnend
#
# This function is defined as:
#
# pid_t __bionic_clone( int flags, void *child_stack,
# pid_t *pid, void *tls, pid_t *ctid,
# int (*fn)(void *), void* arg );
#
# NOTE: This is not the same signature than the GLibc
# __clone function here !! Placing 'fn' and 'arg'
# at the end of the parameter list makes the
# implementation much simpler.
#
.type __bionic_clone, #function
.globl __bionic_clone
.align 4
.fnstart
__bionic_clone:
mov ip, sp
.save {r4, r5, r6, r7}
# save registers to parent stack
stmfd sp!, {r4, r5, r6, r7}
# load extra parameters
ldmfd ip, {r4, r5, r6}
# store 'fn' and 'arg' to the child stack
str r5, [r1, #-4]
str r6, [r1, #-8]
# system call
ldr r7, =__NR_clone
swi #0
movs r0, r0
beq 1f
# in parent, reload saved registers
# then either exit or error
#
ldmfd sp!, {r4, r5, r6, r7}
bxne lr
b __set_syscall_errno
1: # in the child - pick arguments
ldr r0, [sp, #-4]
ldr r1, [sp, #-8]
b __bionic_clone_entry
.fnend

2
libc/arch-arm/syscalls.mk
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@ -4,7 +4,7 @@ syscall_src += arch-arm/syscalls/_exit.S
syscall_src += arch-arm/syscalls/_exit_thread.S
syscall_src += arch-arm/syscalls/__fork.S
syscall_src += arch-arm/syscalls/waitid.S
syscall_src += arch-arm/syscalls/__clone.S
syscall_src += arch-arm/syscalls/__sys_clone.S
syscall_src += arch-arm/syscalls/execve.S
syscall_src += arch-arm/syscalls/setuid.S
syscall_src += arch-arm/syscalls/getuid.S

14
libc/arch-arm/syscalls/__clone.S → libc/arch-arm/syscalls/__sys_clone.S
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@ -2,17 +2,19 @@
#include <sys/linux-syscalls.h>
.text
.type __clone, #function
.globl __clone
.type __sys_clone, #function
.globl __sys_clone
.align 4
.fnstart
__clone:
.save {r4, r7}
stmfd sp!, {r4, r7}
__sys_clone:
mov ip, sp
.save {r4, r5, r6, r7}
stmfd sp!, {r4, r5, r6, r7}
ldmfd ip, {r4, r5, r6}
ldr r7, =__NR_clone
swi #0
ldmfd sp!, {r4, r7}
ldmfd sp!, {r4, r5, r6, r7}
movs r0, r0
bxpl lr
b __set_syscall_errno

5
libc/arch-sh/bionic/clone.S
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@ -72,3 +72,8 @@ __return:
.align 2
0: .long __NR_clone
1: .long __thread_entry
/* XXX: TODO: Add __bionic_clone here
* See bionic/bionic_clone.c and arch-arm/bionic/clone.S
* for more details...
*/

2
libc/arch-sh/syscalls.mk
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@ -5,7 +5,7 @@ syscall_src += arch-sh/syscalls/_exit_thread.S
syscall_src += arch-sh/syscalls/__fork.S
syscall_src += arch-sh/syscalls/_waitpid.S
syscall_src += arch-sh/syscalls/waitid.S
syscall_src += arch-sh/syscalls/__clone.S
syscall_src += arch-sh/syscalls/__sys_clone.S
syscall_src += arch-sh/syscalls/execve.S
syscall_src += arch-sh/syscalls/setuid.S
syscall_src += arch-sh/syscalls/getuid.S

11
libc/arch-sh/syscalls/__clone.S → libc/arch-sh/syscalls/__sys_clone.S
View File

@ -2,15 +2,18 @@
#include <sys/linux-syscalls.h>
.text
.type __clone, @function
.globl __clone
.type __sys_clone, @function
.globl __sys_clone
.align 4
__clone:
__sys_clone:
/* get ready for additonal arg */
mov.l @r15, r0
/* invoke trap */
mov.l 0f, r3 /* trap num */
trapa #(4 + 0x10)
trapa #(5 + 0x10)
/* check return value */
cmp/pz r0

5
libc/arch-x86/bionic/clone.S
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@ -48,3 +48,8 @@ __pthread_clone:
popl %ecx
popl %ebx
ret
/* XXX: TODO: Add __bionic_clone here
* See bionic/bionic_clone.c and arch-arm/bionic/clone.S
* for more details...
*/

2
libc/arch-x86/syscalls.mk
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@ -5,7 +5,7 @@ syscall_src += arch-x86/syscalls/_exit_thread.S
syscall_src += arch-x86/syscalls/__fork.S
syscall_src += arch-x86/syscalls/_waitpid.S
syscall_src += arch-x86/syscalls/waitid.S
syscall_src += arch-x86/syscalls/__clone.S
syscall_src += arch-x86/syscalls/__sys_clone.S
syscall_src += arch-x86/syscalls/execve.S
syscall_src += arch-x86/syscalls/setuid.S
syscall_src += arch-x86/syscalls/getuid.S

17
libc/arch-x86/syscalls/__clone.S → libc/arch-x86/syscalls/__sys_clone.S
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@ -2,19 +2,21 @@
#include <sys/linux-syscalls.h>
.text
.type __clone, @function
.globl __clone
.type __sys_clone, @function
.globl __sys_clone
.align 4
__clone:
__sys_clone:
pushl %ebx
pushl %ecx
pushl %edx
pushl %esi
mov 20(%esp), %ebx
mov 24(%esp), %ecx
mov 28(%esp), %edx
mov 32(%esp), %esi
pushl %edi
mov 24(%esp), %ebx
mov 28(%esp), %ecx
mov 32(%esp), %edx
mov 36(%esp), %esi
mov 40(%esp), %edi
movl $__NR_clone, %eax
int $0x80
cmpl $-129, %eax
@ -25,6 +27,7 @@ __clone:
addl $4, %esp
orl $-1, %eax
1:
popl %edi
popl %esi
popl %edx
popl %ecx

81
libc/bionic/bionic_clone.c Normal file
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@ -0,0 +1,81 @@
/*
* Copyright (C) 2010 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.
*/
#define __GNU_SOURCE 1
#include <sched.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
/* WARNING: AT THE MOMENT, THIS IS ONLY SUPPORTED ON ARM
*/
extern int __bionic_clone(unsigned long clone_flags,
void* newsp,
int *parent_tidptr,
void *new_tls,
int *child_tidptr,
int (*fn)(void *),
void *arg);
extern void _exit_thread(int retCode);
/* this function is called from the __bionic_clone
* assembly fragment to call the thread function
* then exit. */
extern void
__bionic_clone_entry( int (*fn)(void *), void *arg )
{
int ret = (*fn)(arg);
_exit_thread(ret);
}
int
clone(int (*fn)(void *), void *child_stack, int flags, void* arg, ...)
{
va_list args;
int *parent_tidptr = NULL;
void *new_tls = NULL;
int *child_tidptr = NULL;
int ret;
/* extract optional parameters - they are cummulative */
va_start(args, arg);
if (flags & (CLONE_PARENT_SETTID|CLONE_SETTLS|CLONE_CHILD_SETTID)) {
parent_tidptr = va_arg(args, int*);
}
if (flags & (CLONE_SETTLS|CLONE_CHILD_SETTID)) {
new_tls = va_arg(args, void*);
}
if (flags & CLONE_CHILD_SETTID) {
child_tidptr = va_arg(args, int*);
}
va_end(args);
ret = __bionic_clone(flags, child_stack, parent_tidptr, new_tls, child_tidptr, fn, arg);
return ret;
}

1
libc/docs/CHANGES.TXT
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@ -46,6 +46,7 @@ Differences between current and Android 2.1:
- <wchar.h>: Add mbstowcs() and wcstombs()
- add clone() implementation for ARM (x86 and SH-4 not working yet)
-------------------------------------------------------------------------------
Differences between Android 2.1 and 2.0.1:

5
libc/include/sched.h
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@ -69,8 +69,9 @@ extern int sched_rr_get_interval(pid_t pid, struct timespec *tp);
#define CLONE_CHILD_SETTID 0x01000000
#define CLONE_STOPPED 0x02000000
extern int clone(int (*fn)(void*), void *child_stack, int flags, void *arg);
extern pid_t __clone(int, void *);
#ifdef __GNU_SOURCE
extern int clone(int (*fn)(void *), void *child_stack, int flags, void* arg, ...);
#endif
__END_DECLS

2
libc/include/sys/linux-unistd.h
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@ -10,7 +10,7 @@ void _exit_thread (int);
pid_t __fork (void);
pid_t _waitpid (pid_t, int*, int, struct rusage*);
int waitid (int, pid_t, struct siginfo_t*, int,void*);
pid_t __clone (int (*fn)(void*), void *child_stack, int flags, void *arg);
pid_t __sys_clone (int, void*, int*, void*, int*);
int execve (const char*, char* const*, char* const*);
int setuid (uid_t);
uid_t getuid (void);