auto/types脚本分析-part11
本节我们主要分析auto/types目录下的4个脚本文件:sizeof脚本
,typedef脚本
,uintptr_t脚本
以及value脚本
。
顾名思义,auto/types目录下的这些脚本主要就是处理类型相关的一些工作。
1. auto/types/sizeof脚本
脚本内容如下:
# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.
echo $ngx_n "checking for $ngx_type size ...$ngx_c"
cat << END >> $NGX_AUTOCONF_ERR
----------------------------------------
checking for $ngx_type size
END
ngx_size=
cat << END > $NGX_AUTOTEST.c
#include <sys/types.h>
#include <sys/time.h>
$NGX_INCLUDE_UNISTD_H
#include <signal.h>
#include <stdio.h>
#include <sys/resource.h>
$NGX_INCLUDE_INTTYPES_H
$NGX_INCLUDE_AUTO_CONFIG_H
int main() {
printf("%d", (int) sizeof($ngx_type));
return 0;
}
END
ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"
eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
if [ -x $NGX_AUTOTEST ]; then
ngx_size=`$NGX_AUTOTEST`
echo " $ngx_size bytes"
fi
case $ngx_size in
4)
ngx_max_value=2147483647
ngx_max_len='(sizeof("-2147483648") - 1)'
;;
8)
ngx_max_value=9223372036854775807LL
ngx_max_len='(sizeof("-9223372036854775808") - 1)'
;;
*)
echo
echo "$0: error: can not detect $ngx_type size"
echo "----------" >> $NGX_AUTOCONF_ERR
cat $NGX_AUTOTEST.c >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
echo $ngx_test >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
rm -rf $NGX_AUTOTEST*
exit 1
esac
rm -rf $NGX_AUTOTEST*
下面我们对脚本进行分析:
1.1 打印相关提示信息
分别向控制台及autoconf.err文件中打印相应的提示信息:
echo $ngx_n "checking for $ngx_type size ...$ngx_c"
cat << END >> $NGX_AUTOCONF_ERR
----------------------------------------
checking for $ngx_type size
END
$ngx_n
与$ngx_c
我们前面讲述过,主要是为了禁止换行。$ngx_type
为当前我们需要检查的数据类型。
1.2 生成并编译程序
ngx_size=
cat << END > $NGX_AUTOTEST.c
#include <sys/types.h>
#include <sys/time.h>
$NGX_INCLUDE_UNISTD_H
#include <signal.h>
#include <stdio.h>
#include <sys/resource.h>
$NGX_INCLUDE_INTTYPES_H
$NGX_INCLUDE_AUTO_CONFIG_H
int main() {
printf("%d", (int) sizeof($ngx_type));
return 0;
}
END
ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"
eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
将ngx_size值置为空,接着生成objs/autotest.c程序,然后编译。这里$NGX_LD_OPT
与$ngx_feature_libs
值为空.
NGX_INCLUDE_UNISTD_H
与NGX_INCLUDE_INTTYPES_H
通过在auto/headers脚本调用auto/include分别被设置为了#include<unistd.h>
与#include <inttypes.h>
。而NGX_INCLUDE_AUTO_CONFIG_H
会在auto/unix脚本中根据需要进行设置。
1.3 执行程序,并根据执行结果进行处理
if [ -x $NGX_AUTOTEST ]; then
ngx_size=`$NGX_AUTOTEST`
echo " $ngx_size bytes"
fi
case $ngx_size in
4)
ngx_max_value=2147483647
ngx_max_len='(sizeof("-2147483648") - 1)'
;;
8)
ngx_max_value=9223372036854775807LL
ngx_max_len='(sizeof("-9223372036854775808") - 1)'
;;
*)
echo
echo "$0: error: can not detect $ngx_type size"
echo "----------" >> $NGX_AUTOCONF_ERR
cat $NGX_AUTOTEST.c >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
echo $ngx_test >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
rm -rf $NGX_AUTOTEST*
exit 1
esac
判断生成的objs/autotest文件是否可执行,可执行的话则执行程序并将结果保存到ngx_size变量中。然后根据ngx_size的值计算出对应的最大值保存在ngx_max_value变量中,最大长度值保存在ngx_max_len变量中。
1.4 删除生成的测试程序
rm -rf $NGX_AUTOTEST*
2. auto/types/typedef脚本
脚本内容如下:
# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.
echo $ngx_n "checking for $ngx_type ...$ngx_c"
cat << END >> $NGX_AUTOCONF_ERR
----------------------------------------
checking for $ngx_type
END
ngx_found=no
for ngx_try in $ngx_type $ngx_types
do
cat << END > $NGX_AUTOTEST.c
#include <sys/types.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <netinet/in.h>
$NGX_INCLUDE_INTTYPES_H
int main() {
$ngx_try i = 0;
return (int) i;
}
END
ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"
eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
if [ -x $NGX_AUTOTEST ]; then
if [ $ngx_try = $ngx_type ]; then
echo " found"
ngx_found=yes
else
echo ", $ngx_try used"
ngx_found=$ngx_try
fi
fi
if [ $ngx_found = no ]; then
if [ $ngx_try = $ngx_type ]; then
echo $ngx_n " $ngx_try not found$ngx_c"
else
echo $ngx_n ", $ngx_try not found$ngx_c"
fi
echo "----------" >> $NGX_AUTOCONF_ERR
cat $NGX_AUTOTEST.c >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
echo $ngx_test >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
fi
rm -rf $NGX_AUTOTEST*
if [ $ngx_found != no ]; then
break
fi
done
if [ $ngx_found = no ]; then
echo
echo "$0: error: can not define $ngx_type"
exit 1
fi
if [ $ngx_found != yes ]; then
echo "typedef $ngx_found $ngx_type;" >> $NGX_AUTO_CONFIG_H
fi
2.1 打印相关提示信息
echo $ngx_n "checking for $ngx_type ...$ngx_c"
cat << END >> $NGX_AUTOCONF_ERR
----------------------------------------
checking for $ngx_type
END
$ngx_n
与$ngx_c
我们前面讲述过,主要是为了禁止换行。$ngx_type
为当前我们需要检查的数据类型。
2.2 循环检查对应的类型
ngx_found=no
for ngx_try in $ngx_type $ngx_types
do
cat << END > $NGX_AUTOTEST.c
#include <sys/types.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <netinet/in.h>
$NGX_INCLUDE_INTTYPES_H
int main() {
$ngx_try i = 0;
return (int) i;
}
END
ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT $ngx_feature_libs"
eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
if [ -x $NGX_AUTOTEST ]; then
if [ $ngx_try = $ngx_type ]; then
echo " found"
ngx_found=yes
else
echo ", $ngx_try used"
ngx_found=$ngx_try
fi
fi
if [ $ngx_found = no ]; then
if [ $ngx_try = $ngx_type ]; then
echo $ngx_n " $ngx_try not found$ngx_c"
else
echo $ngx_n ", $ngx_try not found$ngx_c"
fi
echo "----------" >> $NGX_AUTOCONF_ERR
cat $NGX_AUTOTEST.c >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
echo $ngx_test >> $NGX_AUTOCONF_ERR
echo "----------" >> $NGX_AUTOCONF_ERR
fi
rm -rf $NGX_AUTOTEST*
if [ $ngx_found != no ]; then
break
fi
done
上面循环检查$ngx_type
与$ngx_types
,尝试找到一个可用的类型。
2.3 后续处理
if [ $ngx_found = no ]; then
echo
echo "$0: error: can not define $ngx_type"
exit 1
fi
if [ $ngx_found != yes ]; then
echo "typedef $ngx_found $ngx_type;" >> $NGX_AUTO_CONFIG_H
fi
如果找到的可用类型不是$ngx_type
的话,则用typedef定义之,并将结果写到objs/ngx_auto_config.h头文件中。
3. auto/types/uintptr_t脚本
脚本内容如下:
# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.
echo $ngx_n "checking for uintptr_t ...$ngx_c"
cat << END >> $NGX_AUTOCONF_ERR
----------------------------------------
checking for uintptr_t
END
found=no
cat << END > $NGX_AUTOTEST.c
#include <sys/types.h>
$NGX_INTTYPES_H
int main() {
uintptr_t i = 0;
return (int) i;
}
END
ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT"
eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
if [ -x $NGX_AUTOTEST ]; then
echo " uintptr_t found"
found=yes
else
echo $ngx_n " uintptr_t not found" $ngx_c
fi
rm -rf $NGX_AUTOTEST*
if [ $found = no ]; then
found="uint`expr 8 \* $ngx_ptr_size`_t"
echo ", $found used"
echo "typedef $found uintptr_t;" >> $NGX_AUTO_CONFIG_H
echo "typedef $found intptr_t;" | sed -e 's/u//g' >> $NGX_AUTO_CONFIG_H
fi
下面进行脚本分析:
3.1 打印相关提示信息
echo $ngx_n "checking for uintptr_t ...$ngx_c"
cat << END >> $NGX_AUTOCONF_ERR
----------------------------------------
checking for uintptr_t
END
$ngx_n
与$ngx_c
我们前面讲述过,主要是为了禁止换行。
3.2 生成并编译程序
found=no
cat << END > $NGX_AUTOTEST.c
#include <sys/types.h>
$NGX_INTTYPES_H
int main() {
uintptr_t i = 0;
return (int) i;
}
END
ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
-o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT"
eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"
NGX_INTTYPES_H
在auto/headers脚本调用中被设置:
auto/include脚本如下行: eval "NGX_$ngx_name='#include <$ngx_include>'"
3.3 执行程序,并根据结果进行处理
if [ -x $NGX_AUTOTEST ]; then
echo " uintptr_t found"
found=yes
else
echo $ngx_n " uintptr_t not found" $ngx_c
fi
rm -rf $NGX_AUTOTEST*
if [ $found = no ]; then
found="uint`expr 8 \* $ngx_ptr_size`_t"
echo ", $found used"
echo "typedef $found uintptr_t;" >> $NGX_AUTO_CONFIG_H
echo "typedef $found intptr_t;" | sed -e 's/u//g' >> $NGX_AUTO_CONFIG_H
fi
判断生成的程序是否可执行,可执行的话将found置为yes,否则会用调用如下语句:
found="uint`expr 8 \* $ngx_ptr_size`_t"
这里$ngx_ptr_size
为我们在文章开头auto/types/sizeof脚本求的当前机器字长(在/auto/unix脚本中调用获得)。
然后将found通过typedef的方式定义成uintptr_t并写入到objs/ngx_auto_config.h头文件中。
4. auto/types/value脚本
脚本内容如下:
# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.
cat << END >> $NGX_AUTO_CONFIG_H
#ifndef $ngx_param
#define $ngx_param $ngx_value
#endif
END
向objs/ngx_auto_config.h头文件写入相应的宏定义。