Fixing File Permissions on Linux

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

The goal is to create a coexistence environment where:

1. You (User): Have full control to edit code and upload files via SFTP.
2. Web Server (www-data): Has permission to run the application and write to the bases folder.
3. ABCD Binaries: Have execution rights.

Step 1: User & Group Setup

First, add your current user to the web server's group (www-data).

# Add your user to the apache 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

Assuming ABCD is installed in /var/www/html/ABCD:

# Set you as the owner and www-data as the group owner
sudo chown -R $USER:www-data /var/www/html/ABCD

Step 3: Write Permissions & SGID

We will use the SGID (Set Group ID) bit. This ensures that any new file created inside these folders automatically inherits the www-data group, preventing future permission lockouts.

A. Application Folders (Code)

Code folders (htdocs) should be editable by you and readable by the server.

# Set permissions 2775 (rwxrwxr-x + SGID) for directories
sudo find /var/www/html/ABCD -type d -exec chmod 2775 {} \;

# Set permissions 0664 (rw-rw-r--) for files
sudo find /var/www/html/ABCD -type f -exec chmod 0664 {} \;

B. The cgi-bin Directory (Executables)

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

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

C. Temporary & Upgrade Folders

If you use the built-in Update Manager, the server needs full write access to create temporary directories.

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

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_PATH="/var/www/html/ABCD"
WS_GROUP="www-data"
CURRENT_USER=$(whoami)

echo "1. Setting Ownership to $CURRENT_USER:$WS_GROUP..."
sudo chown -R $CURRENT_USER:$WS_GROUP $ABCD_PATH

echo "2. Applying directory permissions (2775)..."
sudo find $ABCD_PATH -type d -exec chmod 2775 {} \;

echo "3. Applying file permissions (0664)..."
sudo find $ABCD_PATH -type f -exec chmod 0664 {} \;

echo "4. Restoring executables..."
sudo chmod -R +x $ABCD_PATH/cgi-bin/

echo "Done!"