Model the Linux getent command

Author: cmcgee1024

Sources/LinuxPlatform/Linux.swift

@@ -2,6 +2,7 @@ import Foundation
 import SwiftlyCore
 import SystemPackage
 
+typealias sys = SwiftlyCore.SystemCommand
 typealias fs = SwiftlyCore.FileSystem
 
 /// `Platform` implementation for Linux systems.
@@ -605,15 +606,8 @@ public struct Linux: Platform {
 
     public func getShell() async throws -> String {
         let userName = ProcessInfo.processInfo.userName
-        let prefix = "\(userName):"
-        if let passwds = try await runProgramOutput("getent", "passwd") {
-            for line in passwds.components(separatedBy: "\n") {
-                if line.hasPrefix(prefix) {
-                    if case let comps = line.components(separatedBy: ":"), comps.count > 1 {
-                        return comps[comps.count - 1]
-                    }
-                }
-            }
+        if let entry = try await sys.getent(database: "passwd", keys: userName).entries(self).first {
+            if let shell = entry.last { return shell }
         }
 
         // Fall back on bash on Linux and other Unixes

Sources/SwiftlyCore/Commands.swift

@@ -221,3 +221,61 @@ extension SystemCommand {
 }
 
 extension SystemCommand.PkgbuildCommand: Runnable {}
+
+// get entries from Name Service Switch libraries
+// See getent(1) for more details
+extension SystemCommand {
+    public static func getent(executable: Executable = GetentCommand.defaultExecutable, database: String, keys: String...) -> GetentCommand {
+        Self.getent(executable: executable, database: database, keys: keys)
+    }
+
+    public static func getent(executable: Executable = GetentCommand.defaultExecutable, database: String, keys: [String]) -> GetentCommand {
+        GetentCommand(executable: executable, database: database, keys: keys)
+    }
+
+    public struct GetentCommand {
+        public static var defaultExecutable: Executable { .name("getent") }
+
+        var executable: Executable
+
+        var database: String
+
+        var keys: [String]
+
+        internal init(
+            executable: Executable,
+            database: String,
+            keys: [String]
+        ) {
+            self.executable = executable
+            self.database = database
+            self.keys = keys
+        }
+
+        public func config() -> Configuration {
+            var args: [String] = []
+
+            args += [self.database]
+            args += self.keys
+
+            return Configuration(
+                executable: self.executable,
+                arguments: Arguments(args),
+                environment: .inherit
+            )
+        }
+    }
+}
+
+extension SystemCommand.GetentCommand: Output {
+    public func entries(_ platform: Platform) async throws -> [[String]] {
+        let output = try await output(platform)
+        guard let output else { return [] }
+
+        var entries: [[String]] = []
+        for line in output.components(separatedBy: "\n") {
+            entries.append(line.components(separatedBy: ":"))
+        }
+        return entries
+    }
+}

Tests/SwiftlyTests/CommandLineTests.swift

@@ -46,5 +46,19 @@ public struct CommandLineTests {
 
         config = sys.pkgbuild(.version("1234"), root: "somepath", packageOutputPath: "output").config()
         #expect(String(describing: config) == "pkgbuild --version 1234 --root somepath output")
+
+        config = sys.pkgbuild(.installLocation("/usr/local"), .version("1.0.0"), .identifier("org.foo.bar"), .sign("mycert"), root: "someroot", packageOutputPath: "my.pkg").config()
+        #expect(String(describing: config) == "pkgbuild --install-location /usr/local --version 1.0.0 --identifier org.foo.bar --sign mycert --root someroot my.pkg")
+
+        config = sys.pkgbuild(.installLocation("/usr/local"), .version("1.0.0"), .identifier("org.foo.bar"), root: "someroot", packageOutputPath: "my.pkg").config()
+        #expect(String(describing: config) == "pkgbuild --install-location /usr/local --version 1.0.0 --identifier org.foo.bar --root someroot my.pkg")
+    }
+
+    @Test func testGetent() {
+        var config = sys.getent(database: "passwd", keys: "swiftly").config()
+        #expect(String(describing: config) == "getent passwd swiftly")
+
+        config = sys.getent(database: "foo", keys: "abc", "def").config()
+        #expect(String(describing: config) == "getent foo abc def")
     }
 }