给hello-traditional Debian包添加postinst脚本后未执行的问题排查

我尝试给标准的hello-traditional Debian包添加postinst脚本，步骤如下：

1. 下载并解压该包，在debian目录中添加了一个仅输出字符串的基础postinst脚本：

#!/bin/sh
# This `DEBIAN/postinst` script is run post-installation

set -e
echo "Prova..............."

exit 0

2. 使用以下命令本地重建包：

dpkg-buildpackage -uc -us

或

debuild -us -uc

但测试安装时，postinst脚本未被调用，无法看到echo输出。

附原包中的rules文件：

#!/usr/bin/make -f
# Sample debian/rules file - for GNU Hello.
# Copyright 1994,1995 by Ian Jackson.
# I hereby give you perpetual unlimited permission to copy,
# modify and relicense this file, provided that you do not remove
# my name from the file itself.  (I assert my moral right of
# paternity under the Copyright, Designs and Patents Act 1988.)
# This file may have to be extensively modified

package = hello-traditional
docdir = debian/tmp/usr/share/doc/$(package)

BUILD_DATE := $(shell dpkg-parsechangelog -S Date)

CFLAGS := `dpkg-buildflags --get CFLAGS` -Wall
LDFLAGS := `dpkg-buildflags --get LDFLAGS`
CPPFLAGS := `dpkg-buildflags --get CPPFLAGS`

STRIP = true

export DEB_HOST_GNU_TYPE  ?= $(shell dpkg-architecture -qDEB_HOST_GNU_TYPE)
export DEB_BUILD_GNU_TYPE ?= $(shell dpkg-architecture -qDEB_BUILD_GNU_TYPE)

export AM_UPDATE_INFO_DIR = no

# Recommended snippet for Autoconf 2.52 or later
ifeq ($(DEB_BUILD_GNU_TYPE), $(DEB_HOST_GNU_TYPE))
  confflags += --build $(DEB_HOST_GNU_TYPE)
  stripcmd = strip
else
  confflags += --build $(DEB_BUILD_GNU_TYPE) --host $(DEB_HOST_GNU_TYPE)
  stripcmd = $(DEB_HOST_GNU_TYPE)-strip
endif

ifeq (,$(findstring nostrip,$(DEB_BUILD_OPTIONS)))
  STRIP = $(stripcmd) --remove-section=.comment --remove-section=.note
endif

build:
    ./configure CFLAGS="$(CFLAGS)" CPPFLAGS="$(CPPFLAGS)" \
        LDFLAGS="$(LDFLAGS)" $(confflags) --prefix=/usr
    $(MAKE)
    touch build

clean:
    rm -f build
    [ ! -f Makefile ] || $(MAKE) distclean
    rm -rf *~ debian/tmp debian/*~ debian/files* debian/substvars

binary-indep: build
# There are no architecture-independent files to be uploaded
# generated by this package.  If there were any they would be
# made here.

binary-arch: build
    rm -rf debian/tmp
    install -d debian/tmp/DEBIAN $(docdir)
    $(MAKE) prefix="$$(pwd)/debian/tmp/usr" install
    $(STRIP) debian/tmp/usr/bin/hello
    cp -a NEWS debian/copyright $(docdir)
    cp -a debian/changelog $(docdir)/changelog.Debian
    cp -a ChangeLog $(docdir)/changelog
    cd $(docdir) && gzip -9n changelog changelog.Debian
    gzip -r9n debian/tmp/usr/share/man
    gzip -9n debian/tmp/usr/share/info/*
    dpkg-shlibdeps debian/tmp/usr/bin/hello
    dpkg-gencontrol
    cd debian/tmp && \
        find * -type f ! -regex "DEBIAN/.*" -print0 |\
        LC_ALL=C sort -z | xargs -0r md5sum > DEBIAN/md5sums
    chown -R 0:0 debian/tmp
    chmod -R u+w,go=rX debian/tmp
    find debian/tmp -newermt '$(BUILD_DATE)' -print0 |\
         xargs -0r touch -h --date='$(BUILD_DATE)'
    dpkg --build debian/tmp ..

binary: binary-indep binary-arch

build-arch: build

build-indep: build

.PHONY: binary binary-arch binary-indep build-arch build-indep clean

核心原因 #

你把postinst脚本放在了debian目录下，但从rules文件的binary-arch步骤可以看到，构建过程是直接在debian/tmp/DEBIAN目录下组装包的，但没有将debian目录下的postinst脚本复制到debian/tmp/DEBIAN目录中。Debian包的维护脚本（postinst、prerm等）必须存在于最终构建目录的DEBIAN子目录下，才会被打包进deb包并在安装时执行。

解决步骤 #

1. 调整脚本位置（可选）：建议将postinst脚本命名为debian/hello-traditional.postinst（格式为debian/<包名>.postinst），这是Debian包维护的标准命名方式，便于后续管理。
2. 修改rules文件：在binary-arch步骤里，找到install -d debian/tmp/DEBIAN $(docdir)这一行之后，添加复制脚本的命令：

   install -m 755 debian/postinst debian/tmp/DEBIAN/
   

   如果用了标准命名，则改为：

   install -m 755 debian/$(package).postinst debian/tmp/DEBIAN/postinst
   

   注意必须给脚本设置755权限，否则dpkg会拒绝执行它。
3. 重新构建验证：再次运行dpkg-buildpackage -uc -us或debuild -us -uc生成新包，安装后即可看到echo的输出。

额外验证方法 #

• 用dpkg-deb -c <生成的deb包>查看包内容，确认./DEBIAN/postinst存在且权限为755；
• 用dpkg-deb -e <deb包> <临时目录>提取DEBIAN目录，直接检查脚本是否存在。

内容的提问来源于stack exchange，提问作者LPs