将预先准备好的输入参数字符串作为输入参数传递给程序 (mailx)

如何解决将预先准备好的输入参数字符串作为输入参数传递给程序 (mailx)

我正在创建一个工具来解析输入文件以重新构建 mailx 命令（为 mailx 创建数据的服务器无法发送电子邮件，因此我需要将数据存储到文件中，以便另一台服务器可以重建命令和发送）。我可以将整个命令输出到一个文件并在另一台服务器上执行该文件，但这几乎不安全/不安全......任何人都可以拦截该文件并插入将以 root 身份运行的恶意内容 - 这个解析工具正在检查每个使用 systemd 计时器和服务解析和通过电子邮件发送任何文件的时间。

我已经创建了该文件，使用了以下格式的“标记/分隔符”：

-------MESSAGE START-------
Email Body Text
Goes Here
-------MESSAGE END-------
-------SUBJECT START-------
Email Subject
-------SUBJECT END-------
-------ATTACHEMENT START-------
path to file to attach if supplied
-------ATTACHEMENT END-------
-------S OPTS START-------
list of mailx '-S' options eg from=EMAILNAME <email@b.c> or sendwait etc each one on a new line
-------S OPTS END-------
-------EMAIL LIST START-------
string of recipient emails comma separated eg. email1,email2,email3 etc..
-------EMAIL LIST END-------

我有一个程序来解析这个文件并重建，然后运行mailx命令：

#!/bin/bash

## Using systemd logging to journal for this as its Now being called as part of a service
## See: https://serverfault.com/questions/573946/how-can-i-send-a-message-to-the-systemd-journal-froma-the-command-line (kkm answer)

start_time="$(date +[%c])"
exec 4>&2 2> >(while read -r REPLY; do printf >&4 '<3>%s\n' "$REPLY"; done)
echo >&4 "<5>$start_time  -- Started gpfs_flag_email.sh"

trap_exit(){
    exec >2&
}
trap 'trap_exit' EXIT 

email_flag_path="<PATH TO LOCATION>/email_flags/"
mailx_message_start="-------MESSAGE START-------"
mailx_message_end="-------MESSAGE END-------"
mailx_subject_start="-------SUBJECT START-------"
mailx_subject_end="-------SUBJECT END-------"
mailx_attachement_start="-------ATTACHEMENT START-------"
mailx_attachement_end="-------ATTACHEMENT END-------"
mailx_s_opts_start="-------S OPTS START-------"
mailx_s_opts_end="-------S OPTS END-------"
mailx_to_email_start="-------EMAIL LIST START-------"
mailx_to_email_end="-------EMAIL LIST END-------"
no_attachment=false
no_additional_opts=false
additional_args_switch="-S "


num_files_in_flag_path="$(find $email_flag_path -type f | wc -l)"
if [[ $num_files_in_flag_path -gt 0 ]]; then
    for file in $email_flag_path*; do
        email_message="$(awk "/$mailx_message_start/,/$mailx_message_end/" $file | egrep -v -- "$mailx_message_start|$mailx_message_end")"
        email_subject="$(awk "/$mailx_subject_start/,/$mailx_subject_end/" $file | egrep -v -- "$mailx_subject_start|$mailx_subject_end")"
        email_attachment="$(awk "/$mailx_attachement_start/,/$mailx_attachement_end/" $file | egrep -v -- "$mailx_attachement_start|$mailx_attachement_end")"
        email_additional_opts="$(awk "/$mailx_s_opts_start/,/$mailx_s_opts_end/" $file | egrep -v -- "$mailx_s_opts_start|$mailx_s_opts_end")"
        email_addresses="$(awk "/$mailx_to_email_start/,/$mailx_to_email_end/" $file | egrep -v -- "$mailx_to_email_start|$mailx_to_email_end" | tr -d '\n')"
        if [[ -z "$email_message" || -z "$email_subject" || -z "$email_addresses" ]]; then
            echo >&2 "MISSING DETAILS IN INPUT FILE $file.... Exiting With Error"
            exit 1
        fi

        if [[ -z "$email_attachment" ]]; then
            no_attachment=true
        fi
        if [[ -z "$email_additional_opts" ]]; then
            no_additional_opts=true
        else
            additional_opts_string=""
            while read -r line; do 
                if [[ ! $line =~ [^[:space:]] ]]; then
                    continue
                else
                    additional_opts_string="$additional_opts_string \"${additional_args_switch} '$line'\""
                fi
            done <<<"$(echo "$email_additional_opts")"
            additional_opts_string="$(echo ${additional_opts_string:1} | tr -d '\n')"
        fi
        if [[ $no_attachment = true ]]; then
            if [[ $no_additional_opts = true ]]; then
                echo "$email_message" | mailx -s "$email_subject" $email_addresses
            else
                echo "$email_message" | mailx -s "$email_subject" $additional_opts_string $email_addresses
            fi
        else
            if [[ $no_additional_opts = true ]]; then
                echo "$email_message" | mailx -s "$email_subject" -a $email_attachment $email_addresses
            else
                echo "$email_message" | mailx -s "$email_subject" -a $email_attachment $additional_opts_string $email_addresses
            fi
        fi          
    done
fi
find $email_flag_path -type f -delete
exit 0

然而，上面有一个问题，我只能解决..... -S 选项完全搞砸了电子邮件标题，我最终将电子邮件发送给了错误的人（我已经设置了回复-to 和 from 选项，但电子邮件标题混乱，回复电子邮件最终出现在 to: 字段中），如下所示：

To: Me <[e-mail]>,[e-mail],[e-mail] <[e-mail]>,another-email <[e-mail]> 

我要做的就是像在 CLI 中输入一样重建命令：

echo "EMAIL BODY MESSAGE" | mailx -s "EMAIL SUBJECT" -S "from=EMAILNAME <email@b.c>" -S "replyto=EMAILNAME <email@b.c>" -S sendwait [e-mail]

我试过在 ' ' 和 " " 中引用它周围的其他 mailx 参数等等......我已经编写了其他工具将变量作为输入参数传递，所以我无法理解我是如何搞砸的。 ....

任何帮助将不胜感激...

编辑

感谢 Gordon Davisson 的非常有用的评论，我不仅能够修复它，而且还能够理解修复以及使用数组和适当引用变量...关于使用 printf 的提示真的非常有助于帮助我理解我做错了以及如何纠正它：P

declare -a mailx_args_array

...
num_files_in_flag_path="$(find $email_flag_path -type f | wc -l)"
if [[ $num_files_in_flag_path -gt 0 ]]; then
    for file in $email_flag_path*; do
        ....
        mailx_args_array+=( -s "$email_subject" )
                
        if [[ ! -z "$email_attachment" ]]; then
            mailx_args_array+=( -a "$email_attachment" )
        fi
        if [[ ! -z "$email_additional_s_opts" ]]; then
            while read -r s_opt_line; do
                mailx_args_array+=( -S "$s_opt_line" )
            done < <(echo "$email_additional_s_opts")
        fi
        mailx_args_array+=( "$email_addresses" )
        
        echo "$email_message" | mailx "${mailx_args_array[@]}"
    done
fi