Packages (Linux): Auto detect the DBPath directory for pacman on archlinux (#2154)

Fixes #2068

Author: It-is-Sean

src/detection/packages/packages_linux.c

@@ -412,6 +412,33 @@ static uint32_t getFlatpakPackages(FFstrbuf* baseDir, const char* dirname)
     return num_elements;
 }
 
+static uint32_t getPacmanPackages(FFstrbuf* baseDir)
+{
+    FF_STRBUF_AUTO_DESTROY pacmanDir = ffStrbufCreate();
+    // Get path to pacman.conf
+    uint32_t baseDirLen = baseDir->length;
+    ffStrbufAppendS(baseDir, "/etc/pacman.conf");
+
+    // Get DBPath for packages
+    ffParsePropFile(baseDir->chars, "DBPath =", &pacmanDir);
+    // If DBPath is specified
+    if (pacmanDir.length == 0) {
+        ffParsePropFile(baseDir->chars, "RootDir =", &pacmanDir);
+        // If DBpath is not specified and RootDir is specified
+        if (pacmanDir.length ==0)
+            // If both are not specified
+            ffStrbufClear(&pacmanDir);
+        ffStrbufTrimRight(&pacmanDir, '/');
+        ffStrbufAppendS(&pacmanDir, "/var/lib/pacman");
+    }
+    ffStrbufSubstrBefore(baseDir, baseDirLen);
+
+    ffStrbufTrimRight(&pacmanDir, '/');
+    ffStrbufAppendS(&pacmanDir, "/local");
+
+    return getNumElements(baseDir, pacmanDir.chars, true);
+}
+
 static void getPackageCounts(FFstrbuf* baseDir, FFPackagesResult* packageCounts, FFPackagesOptions* options)
 {
     if (!(options->disabled & FF_PACKAGES_FLAG_APK_BIT)) packageCounts->apk += getNumStrings(baseDir, "/lib/apk/db/installed", "C:Q", "apk");
@@ -426,7 +453,7 @@ static void getPackageCounts(FFstrbuf* baseDir, FFPackagesResult* packageCounts,
         packageCounts->nixDefault += ffPackagesGetNix(baseDir, "/nix/var/nix/profiles/default");
         packageCounts->nixSystem += ffPackagesGetNix(baseDir, "/run/current-system");
     }
-    if (!(options->disabled & FF_PACKAGES_FLAG_PACMAN_BIT)) packageCounts->pacman += getNumElements(baseDir, "/var/lib/pacman/local", true);
+    if (!(options->disabled & FF_PACKAGES_FLAG_PACMAN_BIT)) packageCounts->pacman += getPacmanPackages(baseDir);
     if (!(options->disabled & FF_PACKAGES_FLAG_LPKGBUILD_BIT)) packageCounts->lpkgbuild += getNumElements(baseDir, "/opt/Loc-OS-LPKG/lpkgbuild/remove", false);
     if (!(options->disabled & FF_PACKAGES_FLAG_PKGTOOL_BIT)) packageCounts->pkgtool += getNumElements(baseDir, "/var/log/packages", false);
     if (!(options->disabled & FF_PACKAGES_FLAG_RPM_BIT))