Packages(Linux): Auto detect the DBPath directory for pacman on archlinux

[It-is-Sean]

Summary

Replace the original hardcoded pacman database path. Now it will auto detect the DBPath directory configured by /etc/pacman.conf. If DBPath is not set, it will fall back to the default /var/lib/pacman/local.

Related issue

Closes #2068

Changes

• Modified src/detection/packages/packages_linux.c. Added a static function getPacmanPackages

Checklist

• I have tested my changes locally.

[Copilot]

Pull request overview

This pull request implements automatic detection of the pacman database path from /etc/pacman.conf configuration file, replacing the hardcoded path. The change allows fastfetch to correctly detect package counts on Arch Linux systems where the DBPath has been customized from the default location.

Changes:

• Added getPacmanPackages() function to parse the DBPath from /etc/pacman.conf
• Modified package counting to use the new function instead of hardcoded path

[Copilot]

The first parameter to ffParsePropFile should be the full path to the config file, not just baseDir->chars. The function should first build the complete path to /etc/pacman.conf by appending it to baseDir, parse the config file from that path, and then restore baseDir to its original length. The correct pattern is: save baseDir->length, append /etc/pacman.conf to baseDir, call ffParsePropFile(baseDir->chars, ...), then restore using ffStrbufSubstrBefore(baseDir, baseDirLen).

Suggested change

	ffStrbufAppendS(&pacmanDir, "/etc/pacman.conf");
	if (!ffParsePropFile(baseDir->chars, "DBPath =", &pacmanDir))
	ffStrbufSetS(&pacmanDir, "/var/lib/pacman");
	ffStrbufSubstrBefore(&pacmanDir, baseDirLen);
	ffStrbufAppendS(baseDir, "/etc/pacman.conf");
	if (!ffParsePropFile(baseDir->chars, "DBPath =", &pacmanDir))
	ffStrbufSetS(&pacmanDir, "/var/lib/pacman");
	ffStrbufSubstrBefore(baseDir, baseDirLen);

[Copilot]

The variable pacmanDir is initially set to /etc/pacman.conf but is later used to store the database path value. This is confusing. Instead, baseDir should be used to build the config file path (which will be reset later), and a separate variable should hold the parsed DBPath value, or pacmanDir should start empty and only receive the parsed value.

Suggested change

	ffStrbufAppendS(&pacmanDir, "/etc/pacman.conf");
	if (!ffParsePropFile(baseDir->chars, "DBPath =", &pacmanDir))
	ffStrbufSetS(&pacmanDir, "/var/lib/pacman");
	ffStrbufSubstrBefore(&pacmanDir, baseDirLen);
	ffStrbufAppendS(baseDir, "/etc/pacman.conf");
	if (!ffParsePropFile(baseDir->chars, "DBPath =", &pacmanDir))
	ffStrbufSetS(&pacmanDir, "/var/lib/pacman");
	ffStrbufSubstrBefore(baseDir, baseDirLen);

[CarterLi]

What about RootDir and Bedrock?

[It-is-Sean]

Hi! First, I've checked up arch wiki and found that wiki states for DBPath:

"NOTE: if specified, this is an absolute path and the root path is not automatically prepended."

Thus, I suppose if DBPath exists, RootDir is irrelevant according to the docs.

And for the cases when DBPath doesn't exist and RootDir is specified, we can just use [RootDir]/var/lib/pacman/local as the pacmanDir.

Meanwhile, for bedrock, I think getNumElements() will prepend baseDir and would fix the problem, so the final path would be [baseDir][pacmanDir]. I'll try and make another commit.