Troubleshooting: Fixing ABCD File Permissions on Linux

This guide addresses common permission issues where the web server (Apache/Nginx) cannot write to directories, or where an SFTP user cannot edit files created by the system.

This setup ensures a coexistence environment where:

1. You (via SFTP): Have full control to edit code and upload files.
2. Web Server: Has the necessary permissions to run the application and write to data folders.
3. ABCD Binaries (CISIS): Have execution rights.

Prerequisites

• Installation Path: Assumed to be /opt/ABCD.
• Web Server Group: Typically www-data (Ubuntu/Debian) or daemon (XAMPP).
• Your User: The username you use to log in via SSH/SFTP.

info

In the commands below, replace www-data with daemon if you are using XAMPP/LAMPP.

Step 1: User & Group Setup

First, ensure your user belongs to the web server's group. This allows you to edit files that belong to the group without needing to be root.

# Add your current user to the web server group
sudo usermod -aG www-data $USER

Logout Required

After running the command above, you must logout and login again (SSH/SFTP) for the group changes to take effect.

Step 2: Define Ownership

We will set You as the Owner (to facilitate SFTP editing) and the Web Server as the Group.

# Replace <your_username> with your actual login user
sudo chown -R <your_username>:www-data /opt/ABCD

Step 3: Reset Base Permissions & Enable SGID

We will apply a standard permission set:

• Directories (2775): The 2 enables the SGID bit. This ensures that any new file created inside these folders inherits the www-data group automatically, preventing future permission errors.
• Files (0664): Owner and Group can write; others can read.

# Set directories to 2775 (User/Group write + SGID)
sudo find /opt/ABCD/www -type d -exec chmod 2775 {} \;

# Set files to 0664 (User/Group write, Public read)
sudo find /opt/ABCD/www -type f -exec chmod 0664 {} \;

Step 4: ABCD Critical Exceptions

The ABCD software relies on CISIS utilities and flat-file databases. These require specific permissions that differ from standard web applications.

A. The bases Directory (Data Folder)

The application, PHP scripts, and CISIS binaries all compete to read/write/modify text files here. To prevent "Permission Denied" errors during data entry or indexing, full permissions are required.

# Grant full read/write permissions for data operations
sudo chmod -R 777 /opt/ABCD/www/bases/

Security Note

While 777 is generally discouraged in shared hosting, it is often required for the /bases/ directory in ABCD due to the nature of CISIS file manipulation and inverted index generation. Ensure your server firewall is properly configured.

B. The cgi-bin Directory (Executables)

This folder contains the WXIS and other CISIS binaries. They must have the execution bit (+x) set to function.

# Set directory permissions
sudo chmod -R 755 /opt/ABCD/www/cgi-bin/

# Force execution flag on binary files
sudo chmod -R +x /opt/ABCD/www/cgi-bin/

C. Temporary & Upgrade Folders

If you are using the built-in Update Manager, it needs to create temporary directories.

# Allow the web server to create folders for upgrades
sudo chmod -R 777 /opt/ABCD/www/htdocs/upgrade/ 2>/dev/null

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Automated Fix Script

You can save the following script as fix_abcd_perms.sh in your server root to quickly repair permissions in the future.

fix_abcd_perms.sh

#!/bin/bash

# Configuration
ABCD_USER="<your_username>" # Change this to your user
WEBSERVER_GROUP="www-data"  # Change to 'daemon' if using XAMPP
DIR="/opt/ABCD/www"

echo "1. Setting Ownership to $ABCD_USER:$WEBSERVER_GROUP..."
chown -R $ABCD_USER:$WEBSERVER_GROUP $DIR

echo "2. Applying standard permissions (SGID enabled)..."
find $DIR/htdocs -type d -exec chmod 2775 {} \;
find $DIR/htdocs -type f -exec chmod 0664 {} \;

echo "3. Applying strict permissions for Database storage..."
chmod -R 777 $DIR/bases

echo "4. Enabling execution for CISIS binaries..."
chmod -R 755 $DIR/cgi-bin
chmod -R +x $DIR/cgi-bin/*

echo "Done! ABCD permissions are fixed."