编译可在Android上运行的qemu user mode

摘要: 编译可在Android上运行的qemu user mode

编译可在Android上运行的qemu user mode

@(Android研究)[android|qemu]

[TOC]

本文公开首发于阿里聚安全博客：https://jaq.alibaba.com/community/index.htm?spm=0.0.0.0.ycEUXK

前言

本文在Ubuntu 64位系统上对qemu项目进行交叉编译，并且只编译与qemu user mode有关的代码。

下文中的"NDK"若无特殊说明均指"Android NDK"。

下文中"$NDK"表示的是NDK的根目录。

步骤

1. 下载并安装Android NDK

下载并安装Android NDK的过程在这里不做介绍。

2. 下载qemu

3. 设置NDK工具的环境变量

为交叉编译设置Android NDK环境变量：NDK、SYSROOT

4. 编译依赖库

glib

编译可在Android上运行的glib库

编译参考资料：编译可在Android上运行的glib库

libpng12

下载地址：https://sourceforge.net/projects/libpng/files/libpng12/

编译参考资料：编译可在Android上运行的libffi库

5. 创建pkg-config的软链接

ln -s /usr/bin/pkg-config $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-pkg-config

ln命令中的源路径是pkg-config工具的源路径。

如果不创建这个软链接，当执行configure脚本时会报下面的错误：

ERROR: pkg-config binary 'arm-linux-androideabi-pkg-config' not found

6. 修改configure

添加arm的PIE支持

找到下面的代码：

if test "$pie" = ""; then
case "$cpu-$targetos" in
i386-Linux|x86_64-Linux|x32-Linux|i386-OpenBSD|x86_64-OpenBSD)
;;
*)
pie="no"
;;
esac
fi

将"i386-Linux|x86_64-Linux|x32-Linux|i386-OpenBSD|x86_64-OpenBSD"更改为"i386-Linux|x86_64-Linux|x32-Linux|i386-OpenBSD|x86_64-OpenBSD|arm-Linux"。

如果不这么做的后果
使用"readelf -S qemu-arm"查看编译出来的qemu-arm可执行文件的段，可以发现所有在运行时可加载段的地址均以0x60000000为基址。

在configure中有这么一段代码：

# Probe for the need for relocating the user-only binary.
if test "$pie" = "no" ; then
textseg_addr=
case "$cpu" in
arm | i386 | ppc* | s390* | sparc* | x86_64 | x32)
# ??? Rationale for choosing this address
textseg_addr=0x60000000
;;
mips)
# A 256M aligned address, high in the address space, with enough
# room for the code_gen_buffer above it before the stack.
textseg_addr=0x60000000
;;
esac

if [ -n "$textseg_addr" ]; then
cat > $TMPC <<EOF
int main(void) { return 0; }
EOF
textseg_ldflags="-Wl,-Ttext-segment=$textseg_addr"

......

fi

如果$pie等于"no"，textseg_addr的值将为0x60000000，textseg_ldflags将会设置"-Wl,-Ttext-segment=$textseg_addr"这个命令行选项，这个命令行选项指定text段的基址。在脚本的后面textseg_ldflags会被添加到ldflags中。

如果qemu-arm可加载段的基址为0x60000000，当qemu-arm在Android设备上运行时将会发生"Segmentation fault"，详情请参考Android上可执行ELF文件中的段不能有基址。

7. 运行configure

PKG_CONFIG_PATH="$SYSROOT/usr/lib/pkgconfig" ./configure --prefix="$SYSROOT/usr" --target-list=arm-linux-user --disable-system --disable-bsd-user --disable-tools --disable-zlib-test --cross-prefix="arm-linux-androideabi-" --cc="$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-gcc" --host-cc="$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-gcc" --cpu="arm" --cxx="$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-g++" --extra-ldflags="-fPIE -pie --sysroot $SYSROOT -L$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9/ -L$NDK/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi/ -L$NDK/platforms/android-21/arch-arm/usr/lib/" --extra-cflags="-fPIE -pie --sysroot $SYSROOT -I$NDK/sources/cxx-stl/gnu-libstdc++/4.9/include -I$NDK/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi/include -L$NDK/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi/" --disable-guest-agent

命令行解析

configure脚本会在终端输出一些关键的信息，如：用什么编译器，flags等。

PKG_CONFIG_PATH

上面命令中的

PKG_CONFIG_PATH="$SYSROOT/usr/lib/pkgconfig"

是必要的，如果不设置这个宏，configure脚本输出"CFLAGS"的内容见下：

CFLAGS            -O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include   -g

关注"-I"后的路径，首先说一下这个路径是怎么来的，configure脚本中有下面的代码：

glib_req_ver=2.22
glib_modules=gthread-2.0
if test "$modules" = yes; then
glib_modules="$glib_modules gmodule-2.0"
fi

for i in $glib_modules; do
if $pkg_config --atleast-version=$glib_req_ver $i; then
glib_cflags=`$pkg_config --cflags $i`
glib_libs=`$pkg_config --libs $i`
CFLAGS="$glib_cflags $CFLAGS"
LIBS="$glib_libs $LIBS"
libs_qga="$glib_libs $libs_qga"
else
error_exit "glib-$glib_req_ver $i is required to compile QEMU"
fi
done

"glib_cflags=

$pkg_config --cflags $i

"语句会获得glib的包含目录，看这篇文章的人如果电脑上安装有glib2.0可以通过这个命令进行查看输出内容：pkg-config --cflags glib-2.0。

然而这个路径并不是我想要的，因为我现在是交叉编译，目标是ARM，所以我在这里将一个新的pkgconfig目录路径设置到PKG_CONFIG_PATH宏，输入下面的命令查看输出内容：

PKG_CONFIG_PATH="$SYSROOT/usr/lib/pkgconfig" pkg-config --cflags glib-2.0

输出内容：

-I/home/sowuy/Tools/android-ndk-r11b/platforms/android-21/arch-arm/usr/include/glib-2.0 -I/home/sowuy/Tools/android-ndk-r11b/platforms/android-21/arch-arm/usr/lib/glib-2.0/include -I/home/sowuy/Tools/android-ndk-r11b/platforms/android-21/arch-arm/usr/include

会发现此时"-I"后的路径有了改变。

注意：pkgconfig是一个目录，在这个目录中包含了步骤5中安装的依赖库的信息。

--target-list --cpu

--target-list arm-linux-user 意味着编译出来的qemu程序用于user mode，可以执行arm指令，并且这个arm指令的可执行程序的执行环境基于linux系统。
--cpu=arm 意味着编译出的qemu程序只能在arm机器上执行。

--disable-system --disable-bsd-user

--disable-system：不编译system mode的代码。
--disable-bsd-user：不编译bsd user mode的代码。

--cross-prefix

交叉编译工具的前缀，在当前命令行中它的值为"arm-linux-androideabi-"，那么configure脚本会去查找名为arm-linux-androideabi-gcc、arm-linux-androideabi-g++等工具。

--disable-tools

当命令行中有--disable-tools选项时，脚本中的禁用want_tools宏将被设置为"no"，这个宏默认为"yes"。当want_tools宏为"yes"时，会对tools宏进行设置，下面是与want_tools有关的设置tools宏的代码：

tools=""
if test "$want_tools" = "yes" ; then
tools="qemu-img\$(EXESUF) qemu-io\$(EXESUF) $tools"
if [ "$linux" = "yes" -o "$bsd" = "yes" -o "$solaris" = "yes" ] ; then
tools="qemu-nbd\$(EXESUF) $tools"
tools="ivshmem-client\$(EXESUF) ivshmem-server\$(EXESUF) $tools"
fi
fi

configure脚本会将tools宏的内容写入config-host.mak文件。

--disable-guest-agent

当没有这个选项时，编译会报下面的错误：

qga/main.c:327: error: undefined reference to 'lockf'
collect2: error: ld returned 1 exit status
make: *** [qemu-ga] Error 1

为PC编译qemu项目没有这个命令选项时不会报这个错误，然而lockf函数在Android上并不存在，所以为Android编译qemu项目时会报这个错误。

编译错误排除

ld: error: cannot find -lutil

将根目录下的Makefile文件中下面的内容注释：

ifneq ($(wildcard config-host.mak),)
include $(SRC_PATH)/tests/Makefile
endif

ifaddrs.h: No such file or directory

错误信息

qga/commands-posix.c:45:21: fatal error: ifaddrs.h: No such file or directory
#include <ifaddrs.h>
^
compilation terminated.
make: *** [qga/commands-posix.o] Error 1

修复办法

将这个链接中的源文件都下载下来：android-ifaddrs，将下载下来的文件拷贝到qga/目录下。然后找到qga/Makefile.objs文件，将"ifaddrs.o"插入"qga-obj-$(CONFIG_POSIX)"宏中。

mqueue.h: No such file or directory

错误信息

qemu-2.5.0/linux-user/syscall.c:964:20: fatal error: mqueue.h: No such file or directory
#include <mqueue.h>
^
compilation terminated.
make[1]: *** [linux-user/syscall.o] Error 1
make: *** [subdir-arm-linux-user] Error 2

修复办法

将"#include <mqueue.h>"更改为"#include <linux/mqueue.h>"。

char __unused[128 - sizeof(target_sigset_t)];

错误信息

qemu-2.5.0/linux-user/signal.c:1452:18: error: expected identifier or '(' before '[' token
char __unused[128 - sizeof(target_sigset_t)];
^
make[1]: *** [linux-user/signal.o] Error 1
make: *** [subdir-arm-linux-user] Error 2

修复办法

将__unused更改为_unused。

syscall.c:4108:9: error: dereferencing pointer to incomplete type

错误信息

qemu-2.5.0/linux-user/syscall.c:4108:9: error: dereferencing pointer to incomplete type
host->c_iflag =
^

修复办法

将

#define termios host_termios

改为

#ifdef __ANDROID__
#define host_termios termios
#else
#define termios host_termios#endif

disas/arm-a64.cc:67: error: undefined reference to '__cxa_end_cleanup'

错误信息

disas/arm-a64.cc:67: error: undefined reference to '__cxa_end_cleanup'
../disas/arm-a64.o(.ARM.extab+0x0): error: undefined reference to '__gxx_personality_v0'
../disas/arm-a64.o:arm-a64.cc:typeinfo for QEMUDisassembler: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/sowuy/Tools/android-ndk-r11b/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function (see go/missingkeymethod)
/home/sowuy/Tools/android-ndk-r11b/sources/cxx-stl/gnu-libstdc++/4.9/include/bits/list.tcc:106: error: undefined reference to 'std::__detail::_List_node_base::_M_hook(std::__detail::_List_node_base*)'
/home/sowuy/Tools/android-ndk-r11b/sources/cxx-stl/gnu-libstdc++/4.9/include/bits/stl_list.h:1681: error: undefined reference to 'std::__detail::_List_node_base::_M_hook(std::__detail::_List_node_base*)'
/home/sowuy/Tools/android-ndk-r11b/sources/cxx-stl/gnu-libstdc++/4.9/include/bits/stl_list.h:1681: error: undefined reference to 'std::__detail::_List_node_base::_M_hook(std::__detail::_List_node_base*)'
/home/sowuy/Tools/android-ndk-r11b/sources/cxx-stl/gnu-libstdc++/4.9/include/bits/stl_list.h:1681: error: undefined reference to 'std::__detail::_List_node_base::_M_hook(std::__detail::_List_node_base*)'
/home/sowuy/Tools/android-ndk-r11b/sources/cxx-stl/gnu-libstdc++/4.9/include/bits/stl_list.h:1697: error: undefined reference to 'std::__detail::_List_node_base::_M_unhook()'
/home/sowuy/Tools/android-ndk-r11b/sources/cxx-stl/gnu-libstdc++/4.9/include/bits/stl_list.h:1697: error: undefined reference to 'std::__detail::_List_node_base::_M_unhook()'
../disas/libvixl/a64/disasm-a64.o:disasm-a64.cc:typeinfo for vixl::DecoderVisitor: error: undefined reference to 'vtable for __cxxabiv1::__class_type_info'
/home/sowuy/Tools/android-ndk-r11b/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function (see go/missingkeymethod)
../disas/libvixl/a64/disasm-a64.o:disasm-a64.cc:typeinfo for vixl::Disassembler: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/sowuy/Tools/android-ndk-r11b/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function (see go/missingkeymethod)
../disas/libvixl/a64/disasm-a64.o:disasm-a64.cc:typeinfo for vixl::PrintDisassembler: error: undefined reference to 'vtable for __cxxabiv1::__si_class_type_info'
/home/sowuy/Tools/android-ndk-r11b/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function (see go/missingkeymethod)
collect2: error: ld returned 1 exit status
make[1]: *** [qemu-arm] Error 1
make: *** [subdir-arm-linux-user] Error 2

解决办法
在configure中找到下面的代码：

arm)
disas_config "ARM"
if test -n "${cxx}"; then
disas_config "ARM_A64"
fi
;;

将这些代码注释掉：

if test -n "${cxx}"; then
disas_config "ARM_A64"
fi

原因分析
目前在Android NDK中没有64位版本的object。

syscall.c中找不到符号

错误信息

LINK  arm-linux-user/qemu-arm
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'setdomainname'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmget'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmdt'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmat'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_timedsend'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_unlink'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_open'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_setattr'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_timedreceive'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgsnd'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semget'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semop'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgget'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgrcv'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'stime'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'sigorset'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'vhangup'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'sigtimedwait'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'sethostname'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmget'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmdt'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgget'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semget'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgrcv'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'semop'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgsnd'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'futimesat'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_send'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_receive'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'mq_getattr'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgctl'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmat'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'msgrcv'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmat'
linux-user/syscall.o:syscall.c:function do_syscall: error: undefined reference to 'shmat'
collect2: error: ld returned 1 exit status
make[1]: *** [qemu-arm] Error 1
make: *** [subdir-arm-linux-user] Error 2

解决办法
在syscall.c文件中写下面的内容：

#ifdef __ANDROID__

int setdomainname(const char *name, size_t len) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int shmget(key_t key, size_t size, int shmflg) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int shmdt(const void *shmaddr) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int shmctl(int shmid, int cmd, struct shmid_ds *buf) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

void *shmat(int shmid, const void *shmaddr, int shmflg) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int msgctl(int msqid, int cmd, struct msqid_ds *buf) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int mq_timedsend(unsigned long mqdes, const char *msg_ptr,
size_t msg_len, unsigned msg_prio,
const struct timespec *abs_timeout) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int mq_unlink(const char *name) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

unsigned long mq_open(const char *name, int oflag, mode_t mode,
struct mq_attr *attr) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int mq_setattr(unsigned long mqdes, const struct mq_attr *newattr,
struct mq_attr *oldattr) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

ssize_t mq_timedreceive(unsigned long mqdes, char *msg_ptr,
size_t msg_len, unsigned *msg_prio,
const struct timespec *abs_timeout) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int msgsnd(int msqid, const void *msgp, size_t msgsz, int msgflg) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

ssize_t msgrcv(int msqid, void *msgp, size_t msgsz, long msgtyp,
int msgflg) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int semget(key_t key, int nsems, int semflg) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int semop(int semid, struct sembuf *sops, size_t nsops) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int msgget(key_t key, int msgflg) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int stime(const time_t *t) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int sigorset(sigset_t * set, const sigset_t * left, const sigset_t * right) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int vhangup(void) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int sigtimedwait(const sigset_t *set, siginfo_t *info,
const struct timespec *timeout) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int sethostname(const char *name, size_t len) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int semctl(int semid, int semnum, int cmd, ...) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int futimesat(int dirfd, const char *pathname,
const struct timeval times[2]) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int mq_send(unsigned long mqdes, const char *msg_ptr,
size_t msg_len, unsigned int msg_prio) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

ssize_t mq_receive(unsigned long mqdes, char *msg_ptr,
size_t msg_len, unsigned int *msg_prio) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

int mq_getattr(unsigned long mqdes, struct mq_attr *attr) {
printf("[-] %s(%d)-%s\n",__FILE__,__LINE__,__FUNCTION__);
assert(0);
}

#endif

编译清理命令

执行下面两个命令：

make clean

make distclean

编译debug版

调用configure脚本的命令行中添加"--enable-debug"命令选项。