在镜像中添加Git提交号

文章目录

前言
环境介绍
思路
内核cpuinfo中添加Git提交号
- 修改setup.c
- 获取Git提交号和生成GIT_COMMIT_INFO宏
- 继续修改内核setup.c
- 验证
内核设备树中添加Git提交号
- 修改设备树
- 验证
U-Boot版本号添加Git提交号
- U-Boot配置
- 修改setlocalversion脚本
- 验证

前言

在镜像中加入Git提交号，主要用于出现问题时，方便追溯。

环境介绍

硬件：T113
软件：全志Tina 5.0

思路

1、想办法获取当前的提交号。
2、将提交号写入一个头文件中，方便其它函数引用。
3、在cpuinfo或设备树中加入提交号信息，其中提交号从头文件获取即可。

内核cpuinfo中添加Git提交号

修改setup.c

我们知道在cat /proc/cpuinfo时，会打印关于CPU架构、型号、速度、缓存大小、功能等的详细信息，那就将Git提交号放到这里吧，最终效果如下图：

cpuinfo的实现在<SDK>/kernel/linux-5.4/arch/arm/kernel/setup.c中，定位到c_show()函数，在第11行加入打印：

/* setup.c */

...
...

static int c_show(struct seq_file *m, void *v)
{
	int i, j;
	u32 cpuid;

	seq_printf(m, "version\t: %s\n", GIT_COMMIT_INFO);	//打印提交号

	for_each_online_cpu(i) {
		/*
		 * glibc reads /proc/cpuinfo to determine the number of
		 * online processors, looking for lines beginning with
		 * "processor".  Give glibc what it expects.
		 */
		seq_printf(m, "processor\t: %d\n", i);
		cpuid = is_smp() ? per_cpu(cpu_data, i).cpuid : read_cpuid_id();
		seq_printf(m, "model name\t: %s rev %d (%s)\n",
			   cpu_name, cpuid & 15, elf_platform);

#if defined(CONFIG_SMP)
		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
			   per_cpu(cpu_data, i).loops_per_jiffy / (500000UL/HZ),
			   (per_cpu(cpu_data, i).loops_per_jiffy / (5000UL/HZ)) % 100);
#else
		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
			   loops_per_jiffy / (500000/HZ),
			   (loops_per_jiffy / (5000/HZ)) % 100);
#endif
		/* dump out the processor features */
		seq_puts(m, "Features\t: ");

		for (j = 0; hwcap_str[j]; j++)
			if (elf_hwcap & (1 << j))
				seq_printf(m, "%s ", hwcap_str[j]);

		for (j = 0; hwcap2_str[j]; j++)
			if (elf_hwcap2 & (1 << j))
				seq_printf(m, "%s ", hwcap2_str[j]);

		seq_printf(m, "\nCPU implementer\t: 0x%02x\n", cpuid >> 24);
		seq_printf(m, "CPU architecture: %s\n",
			   proc_arch[cpu_architecture()]);

		if ((cpuid & 0x0008f000) == 0x00000000) {
			/* pre-ARM7 */
			seq_printf(m, "CPU part\t: %07x\n", cpuid >> 4);
		} else {
			if ((cpuid & 0x0008f000) == 0x00007000) {
				/* ARM7 */
				seq_printf(m, "CPU variant\t: 0x%02x\n",
					   (cpuid >> 16) & 127);
			} else {
				/* post-ARM7 */
				seq_printf(m, "CPU variant\t: 0x%x\n",
					   (cpuid >> 20) & 15);
			}
			seq_printf(m, "CPU part\t: 0x%03x\n",
				   (cpuid >> 4) & 0xfff);
		}
		seq_printf(m, "CPU revision\t: %d\n\n", cpuid & 15);
	}

	seq_printf(m, "Hardware\t: %s\n", machine_name);
	seq_printf(m, "Revision\t: %04x\n", system_rev);
	seq_printf(m, "Serial\t\t: %s\n", system_serial);

	return 0;
}
    
...
...

那问题来了，这个GIT_COMMIT_INFO宏在哪定义的？

seq_printf(m, "version\t: %s\n", GIT_COMMIT_INFO);	//打印提交号

获取Git提交号和生成GIT_COMMIT_INFO宏

在内核源码中，自带有一个setlocalversion脚本。它的主要作用是为内核版本号添加额外的本地或特定的标识符。当内核源码是从版本控制系统（如 Git）中检出的，并且不在某个特定的标签（tagged commit）上时，setlocalversion脚本会被调用，并在版本号后添加一个 “+” 号以及其他的本地版本信息。
简单概括就是该脚本已经实现了怎么获取提交号，当然使用一句简单的git rev-parse --verify --short HEAD命令也可以获取当前的提交号。我们主要借助现成的完善的可靠的已经经过验证的方法，仅此而已。
找到<SDK>/kernel/linux-5.4/scripts/setlocalversion脚本，主要关注scm_version()函数：

/* setlocalversion */

...
...
    
scm_version()
{
	local short
	short=false

	cd "$srctree"
	if test -e .scmversion; then
		cat .scmversion
		return
	fi
	if test "$1" = "--short"; then
		short=true
	fi

	# Check for git and a git repo.
	if test -z "$(git rev-parse --show-cdup 2>/dev/null)" &&
	   head=`git rev-parse --verify --short HEAD 2>/dev/null`; then

		if [ -n "$android_release" ] && [ -n "$kmi_generation" ]; then
			printf '%s' "-$android_release-$kmi_generation"
		fi

		# If we are at a tagged commit (like "v2.6.30-rc6"), we ignore
		# it, because this version is defined in the top level Makefile.
		if [ -z "`git describe --exact-match 2>/dev/null`" ]; then

			# If only the short version is requested, don't bother
			# running further git commands
			if $short; then
				echo "+"
				return
			fi
			# If we are past a tagged commit (like
			# "v2.6.30-rc5-302-g72357d5"), we pretty print it.
			if atag="`git describe 2>/dev/null`"; then
				echo "$atag" | awk -F- '{printf("-%05d-%s", $(NF-1),$(NF))}'

			# If we don't have a tag at all we print -g{commitish}.
			else
				printf '%s%s' -g $head
			fi
		fi

		# Is this git on svn?
		if git config --get svn-remote.svn.url >/dev/null; then
			printf -- '-svn%s' "`git svn find-rev $head`"
		fi

		# Check for uncommitted changes.
		# First, with git-status, but --no-optional-locks is only
		# supported in git >= 2.14, so fall back to git-diff-index if
		# it fails. Note that git-diff-index does not refresh the
		# index, so it may give misleading results. See
		# git-update-index(1), git-diff-index(1), and git-status(1).
		if {
			git --no-optional-locks status -uno --porcelain 2>/dev/null ||
			git diff-index --name-only HEAD
		} | grep -qvE '^(.. )?scripts/package'; then
			printf '%s' -dirty
		fi

		# All done with git
		return
	fi

	# Check for mercurial and a mercurial repo.
	if test -d .hg && hgid=`hg id 2>/dev/null`; then
		# Do we have an tagged version?  If so, latesttagdistance == 1
		if [ "`hg log -r . --template '{latesttagdistance}'`" = "1" ]; then
			id=`hg log -r . --template '{latesttag}'`
			printf '%s%s' -hg "$id"
		else
			tag=`printf '%s' "$hgid" | cut -d' ' -f2`
			if [ -z "$tag" -o "$tag" = tip ]; then
				id=`printf '%s' "$hgid" | sed 's/[+ ].*//'`
				printf '%s%s' -hg "$id"
			fi
		fi

		# Are there uncommitted changes?
		# These are represented by + after the changeset id.
		case "$hgid" in
			*+|*+\ *) printf '%s' -dirty ;;
		esac

		# All done with mercurial
		return
	fi

	# Check for svn and a svn repo.
	if rev=`LANG= LC_ALL= LC_MESSAGES=C svn info 2>/dev/null | grep '^Last Changed Rev'`; then
		rev=`echo $rev | awk '{print $NF}'`
		printf -- '-svn%s' "$rev"

		# All done with svn
		return
	fi
}

...
...

该函数被执行后，若使用Git管理，则会输出当前的提交号。若没使用Git管理，输出空。知道了该函数的作用后，我们自行在同级目录下，创建一个专门用于生成提交号的脚本scm_version.sh，将scm_version()函数复制进去。脚本的完整内容如下：

#!/bin/bash

INFO_DIR=${LICHEE_KERN_DIR}/include/dt-bindings/cpuinfo.h	

scm_version()
{
	local short
	short=false

	cd "$srctree"
	if test -e .scmversion; then
		cat .scmversion
		return
	fi
	if test "$1" = "--short"; then
		short=true
	fi

	# Check for git and a git repo.
	if head=$(git rev-parse --verify HEAD 2>/dev/null); then

		# If we are at a tagged commit (like "v2.6.30-rc6"), we ignore
		# it, because this version is defined in the top level Makefile.
		if [ -z "$(git describe --exact-match 2>/dev/null)" ]; then

			# If only the short version is requested, don't bother
			# running further git commands
			if $short; then
				# echo "+"
				return
			fi
			# If we are past a tagged commit (like
			# "v2.6.30-rc5-302-g72357d5"), we pretty print it.
			if atag="$(git describe 2>/dev/null)"; then
				echo "$atag" | awk -F- '{printf("-%05d", $(NF-1))}'
			fi

			# Add -g and exactly 12 hex chars.
			printf '%s' "$(echo $head | cut -c1-12)"
		fi

		# Check for uncommitted changes.
		# This script must avoid any write attempt to the source tree,
		# which might be read-only.
		# You cannot use 'git describe --dirty' because it tries to
		# create .git/index.lock .
		# First, with git-status, but --no-optional-locks is only
		# supported in git >= 2.14, so fall back to git-diff-index if
		# it fails. Note that git-diff-index does not refresh the
		# index, so it may give misleading results. See
		# git-update-index(1), git-diff-index(1), and git-status(1).
		if {
			git --no-optional-locks status -uno --porcelain 2>/dev/null ||
			git diff-index --name-only HEAD
		} | read dummy; then
			printf '%s' -dirty
		fi
	fi
}

commit_info="$(scm_version)"

if test -z "${commit_info}" ; then
cat <<EOM >${INFO_DIR}
#define GIT_COMMIT_INFO "null"
EOM

else
cat <<EOM >${INFO_DIR}
#define GIT_COMMIT_INFO "${commit_info}"
EOM

fi

下面解释一下脚本各部分内容：

脚本开头定义了cpuinfo.h文件的路径，脚本最后会创建一个cpuinfo.h，并把GIT_COMMIT_INFO宏写入该文件。可以发现该文件的路径在dt-bindings目录下，后续想要在设备树也添加git提交号的话，直接include该文件即可。【需要注意的是：cpuinfo.h需要加入到.gitignore忽略文件中，否则每次提交后的第一次编译都会检测到cpuinfo.h的修改】

INFO_DIR=${LICHEE_KERN_DIR}/include/dt-bindings/cpuinfo.h

scm_version()
{
    ...
}

commit_info="$(scm_version)"

if test -z "${commit_info}" ; then
cat <<EOM >${INFO_DIR}
#define GIT_COMMIT_INFO "null"
EOM

else
cat <<EOM >${INFO_DIR}
#define GIT_COMMIT_INFO "${commit_info}"
EOM

fi

scm_version()函数也作了修改，第一处修改如下，修改前：

...
    
scm_version()
{
    ...
    if test -z "$(git rev-parse --show-cdup 2>/dev/null)" &&
	   head=`git rev-parse --verify --short HEAD 2>/dev/null`; then
    ...
}

...

修改后：

...
    
scm_version()
{
    ...
    if head=`git rev-parse --verify --short HEAD 2>/dev/null`; then
    ...
}

...

第二处修改如下，修改前：

...
    
scm_version()
{
    ...
    if $short; then
        echo "+"
        return
    fi
    ...
}

...

修改后：

...
    
scm_version()
{
    ...
    if $short; then
        # echo "+"
        return
    fi
    ...
}

...

至此，用于生成提交号的脚本已制作完成。
那我们的脚本怎么被执行？在setlocalversion脚本最后执行即可：

/* setlocalversion */

...

sh ${LICHEE_KERN_DIR}/scripts/scm_version.sh

因为在内核开始编译前，会先执行setlocalversion脚本。借此执行我们自己的脚本。

继续修改内核setup.c

前面已经在<SDK>/kernel/linux-5.4/arch/arm/kernel/setup.c中加了提交号的打印，现在需要引入头文件：

...
    
#include <dt-bindings/cpuinfo.h>

...

验证

cat /proc/cpuinfo查看git提交号：

提交号后面还多了一个dirty字样，表明当前提交还存在未提交的文件，所以该提交号是最近一次提交的。

内核设备树中添加Git提交号

修改设备树

修改内核设备树<SDK>/device/config/chips/t113/configs/evb1_auto/linux-5.4/board.dts，直接引入头文件cpuinfo.h即可：

验证

在uboot命令行执行fdt list /查看：

U-Boot版本号添加Git提交号

U-Boot配置

配置CONFIG_LOCALVERSION_AUTO=y

修改setlocalversion脚本

修改<SDK>/brandy/brandy-2.0/u-boot-2018/scripts/setlocalversion，主要修改其中的scm_version()函数，修改后的scm_version()函数如下：

/* setlocalversion */

...

scm_version()
{
  local short
	short=false

	cd "$srctree"
	if test -e .scmversion; then
		cat .scmversion
		return
	fi
	if test "$1" = "--short"; then
		short=true
	fi

	# Check for git and a git repo.
	if head=`git rev-parse --verify --short HEAD 2>/dev/null`; then

		# If we are at a tagged commit (like "v2.6.30-rc6"), we ignore
		# it, because this version is defined in the top level Makefile.
		if [ -z "`git describe --exact-match 2>/dev/null`" ]; then

			# If only the short version is requested, don't bother
			# running further git commands
			if $short; then
				# echo "+"
				return
			fi
			# If we are past a tagged commit (like
			# "v2.6.30-rc5-302-g72357d5"), we pretty print it.
			if atag="`git describe 2>/dev/null`"; then
				echo "$atag" | awk -F- '{printf("-%05d-%s", $(NF-1),$(NF))}'

			# If we don't have a tag at all we print -g{commitish}.
			else
				printf '%s%s' -g $head
			fi
		else
			printf '%s%s' -g $head
		fi

		# Is this git on svn?
		if git config --get svn-remote.svn.url >/dev/null; then
			printf -- '-svn%s' "`git svn find-rev $head`"
		fi

		# Check for uncommitted changes
		if git diff-index --name-only HEAD | grep -qv "^scripts/package"; then
			printf '%s' -dirty
		fi

		# All done with git
		return
	fi

	# Check for mercurial and a mercurial repo.
	if test -d .hg && hgid=`hg id 2>/dev/null`; then
		# Do we have an tagged version?  If so, latesttagdistance == 1
		if [ "`hg log -r . --template '{latesttagdistance}'`" == "1" ]; then
			id=`hg log -r . --template '{latesttag}'`
			printf '%s%s' -hg "$id"
		else
			tag=`printf '%s' "$hgid" | cut -d' ' -f2`
			if [ -z "$tag" -o "$tag" = tip ]; then
				id=`printf '%s' "$hgid" | sed 's/[+ ].*//'`
				printf '%s%s' -hg "$id"
			fi
		fi

		# Are there uncommitted changes?
		# These are represented by + after the changeset id.
		case "$hgid" in
			*+|*+\ *) printf '%s' -dirty ;;
		esac

		# All done with mercurial
		return
	fi

	# Check for svn and a svn repo.
	if rev=`LANG= LC_ALL= LC_MESSAGES=C svn info 2>/dev/null | grep '^Last Changed Rev'`; then
		rev=`echo $rev | awk '{print $NF}'`
		printf -- '-svn%s' "$rev"

		# All done with svn
		return
	fi
}

...