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In the script, I used main function to create a new sudo-bash to finish all the things with sudo.

#!/bin/bash
function sudo_stuffs() { 
  install_ss
}
function install_ss() {
  echo something
}



main() {
  # 切换目录
  cd /tmp 
  if [[ ! -d "install_shadowsocks" ]]; then
    mkdir install_shadowsocks
  fi
  cd install_shadowsocks

  # 如果没有sudo权限
  if ! sudo -v 1>/dev/null 2>&1 ; then
    # 提示登录有权限的账户 
    echo "--- You don't have authority, login to the root or others in sudoers. ---"
    exit 1
  fi

  export -f install_ss
  FUNC=$(declare -f sudo_stuffs)
  sudo bash -c "$FUNC; sudo_stuffs"
}

main "$@"

But actually in the sudo_stuffs function, there are more detailed functions like install_ss function.

I even used export -f install_ss to make sure install_ss could be found in the sub shell called with sudo bash -c "$FUNC; sudo_stuffs".

But still, the result came with

bash: line 2: install_ss: command not found

what can I do please?

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5
  • Maybe use FUNC=$( declare f sudo_stuffs install_ss )? Also, I would probably do eval "$FUNC" instead of using $FUNC unquoted. Commented Oct 28, 2019 at 11:00
  • Can you specify how you called the script, i.e. did you make it executable and then simply called ./scriptname.sh or did you call it explicitly as a shell argument (like bash scriptname.sh)? Commented Oct 28, 2019 at 11:52
  • The point is, I am rather surprised the script generates any output at all, since bash scripts, as opposed to a compiled C program, don't have a 'default' main function that is automatically executed. I would have believed that your script, actually shouldn't do anything because while you declare the function main(), you never call it inside the script. Commented Oct 28, 2019 at 12:08
  • @Kusalananda Yeah your code works. But why sudo -E doesn't work? It can transfer string environment variables to the newborn shell if there is a export a="1" before the sudo bash -c "$FUNC; sudo_stuffs" line. But the export -f install_ss failed. Commented Oct 28, 2019 at 14:23
  • It fails because an exported function is not an ordinary environment variable. Even allowing ordinary environment variables to be passed via sudo is considered a security flaw by some, and it can be configured to be not allowed in the sudoers file. Commented Oct 28, 2019 at 14:48

3 Answers 3

Reset to default
1

Don't use function, i.e. lines 2-4 would be:

sudo_stuffs() { 
  install_ss
}

Then to call it, just use:

sudo_stuffs

Finally, to get root permission when the user is not root, add these 3 lines to the beginning of your script (after line 1). This will run the script via sudo, which will check that the user has permission to run sudo and (normally) ask for a password :

if [ `id -u` -gt 0 ]; then
    exec sudo "$0" "$@"
fi
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2
  • The point in this question is, I believe, to call the script as a non-privileged user and then have the script only use sudo for the things that actually require root permissions. Commented Oct 28, 2019 at 12:02
  • Okay - maybe I misunderstood. Commented Oct 28, 2019 at 12:17
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I found a duplicate but according to the rule of StackExchange I can't set it.

So I publish it here:

https://askubuntu.com/questions/57915/environment-variables-when-run-with-sudo

The real reason why command missing is sudo command discarded my environment variables which exported from my shell so the sub shell generated by sudo will not be able to know what is install_ss function.

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0

Your line sudo bash -c "$FUNC; sudo_stuffs" looks wrong to me. sudo -c should be followed by the commmand you wish to execute in quotes, end your quotes and then put the username you wish to execute the command as at the end.

sudo -c "bash FUNC sudo_stuffs" MY_USERNAME

allow im not sure if you can call a function in this way. I would usually call my function in the script and if you want the commands that make up your function to be run as a certain user you would add the suco -c "command" my_username to the function.

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2
  • Note that bash $FUNC does not make sense with the expansion of $FUNC being a function definition. Commented Oct 28, 2019 at 12:00
  • Thanks, edited to give it a bit more relevance. Commented Oct 28, 2019 at 12:05

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