add proxy support in install-chroot.sh

build/install-chroot.sh

Index: build/install-chroot.sh
diff --git a/build/install-chroot.sh b/build/install-chroot.sh
index 82caff2385ee87d160cbda474484fc9b182c340b..529d8320b758448ed45627a7eda89a3028221fd9 100755
--- a/build/install-chroot.sh
+++ b/build/install-chroot.sh
@@ -339,8 +339,14 @@ if [ -z "${mirror}" ]; then
    mirror="http://archive.ubuntu.com/ubuntu" ||
    mirror="http://ftp.us.debian.org/debian"
 fi
- sudo debootstrap ${archflag} "${distname}" /var/lib/chroot/"${target}"        \
-                  "$mirror"
+
+if [ -n "${http_proxy}" ]; then
+  PROXY_FLAG="http_proxy=${http_proxy}"
+else
+  PROXY_FLAG=""
+fi
+sudo ${PROXY_FLAG} debootstrap ${archflag} "${distname}"   \

[Markus (顧孟勤), 2012/05/08 02:09:57]

You could probably write this more concisely as:

sudo ${http_proxy:+http_proxy="${http_proxy}"} debootstrap ...

This also has the advantage that it gets the quoting right. If "${http_proxy}"
contains white-space, we'll still forward it correctly.

But if you strongly feel your version is better, I won't fight you over it --
although I'd love if you could then fix the quoting somehow.

[Wei James(wistoch), 2012/05/08 02:47:58]

done. thanks 

+  "/var/lib/chroot/${target}"  "$mirror"
 
 # Add new entry to /etc/schroot/schroot.conf
 grep -qs ubuntu.com /usr/share/debootstrap/scripts/"${distname}" &&
@@ -552,6 +558,13 @@ sudo sed -i '/^deb[^-]/p
              s/^deb\([^-]\)/deb-src\1/' \
          "/var/lib/chroot/${target}/etc/apt/sources.list"
 
+# Set apt proxy if host has set http_proxy
+if [ -n "${http_proxy}" ]; then
+  sudo sh -c '
+    echo "Acquire::http::proxy \"'${http_proxy}'\";" \

[Markus (顧孟勤), 2012/05/08 02:09:57]

While it probably is benign in this particular case, we try to always put
double-quotes around any environment variable, especially if it was provided by
the user. This is not always possible, but here you could trivially add it.
Please do so, as it will make things easier for future reviewers -- they won't
have to scratch their heads whether there was a reason why we left of the
quotes.

[Wei James(wistoch), 2012/05/08 02:47:58]

for the syntax requirement, we need a double-quotes in apt.conf such as: 
Acquire::http::proxy "http://proxy.com:8080";

So i used it in this way. 

I am not very familar with shell, can you tell me how can I get double-quotes in
the echo statement around the  environment variable? thanks 

+        >>"/var/lib/chroot/'"${target}"'/etc/apt/apt.conf"'
+fi
+
 # Update packages
 sudo "/usr/local/bin/${target%bit}" /bin/sh -c '
   apt-get update; apt-get -y dist-upgrade' || :