Support for logging and cat command

package.json

@@ -1,6 +1,6 @@
 {
   "name": "frida-cshell",
-  "version": "1.4.2",
+  "version": "1.4.3",
   "description": "Frida's CShell",
   "scripts": {
     "prepare": "npm run build && npm run version && npm run package && npm run copy",

src/cmdlets/cat.ts

@@ -0,0 +1,38 @@
+import { CmdLet } from '../commands/cmdlet.js';
+import { Output } from '../io/output.js';
+import { Token } from '../io/token.js';
+import { Var } from '../vars/var.js';
+
+const USAGE: string = `Usage: cat
+
+cat file - dump file
+  file      the file to dump`;
+
+export class CatCmdLet extends CmdLet {
+  name = 'cat';
+  category = 'misc';
+  help = 'dump a file';
+
+  public runSync(tokens: Token[]): Var {
+    const vars = this.transform(tokens, [this.parseLiteral]);
+    if (vars === null) return this.usage();
+
+    const [file] = vars as [string];
+    Output.writeln(`Dumping file: ${Output.green(file)}`);
+
+    try {
+      const text = File.readAllText(file);
+      const lines = text.split('\n');
+      lines.forEach(l => Output.writeln(Output.yellow(l), true));
+    } catch {
+      Output.writeln(`failed to read file: ${Output.green(file)}`);
+    }
+
+    return Var.ZERO;
+  }
+
+  public usage(): Var {
+    Output.writeln(USAGE);
+    return Var.ZERO;
+  }
+}

src/cmdlets/js.ts

@@ -56,6 +56,8 @@ import { VarCmdLet } from './var.js';
 import { VmCmdLet } from './vm.js';
 import { WriteCmdLet } from './write.js';
 import { GrepCmdLet } from './grep.js';
+import { CatCmdLet } from './cat.js';
+import { LogCmdLet } from './log.js';
 
 const USAGE: string = `Usage: js
 
@@ -86,6 +88,7 @@ export class JsCmdLet extends CmdLet {
       Bp: Bp,
       Bps: Bps,
       BtCmdLet: BtCmdLet,
+      CatCmdLet: CatCmdLet,
       CharCode: CharCode,
       CmdLets: CmdLets,
       Command: Command,
@@ -105,6 +108,7 @@ export class JsCmdLet extends CmdLet {
       InsnBpCmdLet: InsnBpCmdLet,
       LdCmdLet: LdCmdLet,
       Line: Line,
+      LogCmdLet: LogCmdLet,
       Mem: Mem,
       MemoryBps: MemoryBps,
       ModCmdLet: ModCmdLet,

src/cmdlets/log.ts

@@ -0,0 +1,47 @@
+import { CmdLet } from '../commands/cmdlet.js';
+import { Output } from '../io/output.js';
+import { Token } from '../io/token.js';
+import { Var } from '../vars/var.js';
+
+const USAGE: string = `Usage: log
+
+log - clear log file
+
+log file - set log file
+  file      the file to log to`;
+
+export class LogCmdLet extends CmdLet {
+  name = 'log';
+  category = 'misc';
+  help = 'set log file';
+
+  public runSync(tokens: Token[]): Var {
+    const vars = this.transformOptional(tokens, [], [this.parseLiteral]);
+    if (vars === null) return this.usage();
+    const [_, [file]] = vars as [[], [string | null]];
+    if (file === null) {
+      Output.clearLog();
+      Output.writeln('log file cleared');
+    } else {
+      try {
+        Output.writeln(
+          [
+            'log file set to ',
+            Output.blue("'"),
+            Output.green(file),
+            Output.blue("'"),
+          ].join(''),
+        );
+        Output.setLog(file);
+      } catch {
+        Output.writeln(`invalid log file: ${file}`);
+      }
+    }
+    return Var.ZERO;
+  }
+
+  public usage(): Var {
+    Output.writeln(USAGE);
+    return Var.ZERO;
+  }
+}

src/commands/cmdlets.ts

@@ -47,6 +47,8 @@ import { ShCmdLet } from '../cmdlets/sh.js';
 import { SrcCmdLet } from '../cmdlets/src.js';
 import { VerboseCmdLet } from '../cmdlets/verbose.js';
 import { GrepCmdLet } from '../cmdlets/grep.js';
+import { CatCmdLet } from '../cmdlets/cat.js';
+import { LogCmdLet } from '../cmdlets/log.js';
 
 export class CmdLets {
   private static byName: Map<string, CmdLet> = new Map<string, CmdLet>();
@@ -59,6 +61,7 @@ export class CmdLets {
     this.registerCmdletType(BlockTraceBpCmdLet);
     this.registerCmdletType(BtCmdLet);
     this.registerCmdletType(CallTraceBpCmdLet);
+    this.registerCmdletType(CatCmdLet);
     this.registerCmdletType(CopyCmdLet);
     this.registerCmdletType(CoverageBpCmdLet);
     this.registerCmdletType(DivCmdLet);
@@ -75,6 +78,7 @@ export class CmdLets {
     this.registerCmdletType(InsnBpCmdLet);
     this.registerCmdletType(JsCmdLet);
     this.registerCmdletType(LdCmdLet);
+    this.registerCmdletType(LogCmdLet);
     this.registerCmdletType(OrCmdLet);
     this.registerCmdletType(ReadCmdLet);
     this.registerCmdletType(ModCmdLet);

src/io/output.ts

@@ -26,6 +26,7 @@ export class Output {
   private static verbose: boolean = false;
   private static indent: boolean = false;
   private static filter: RegExp | null = null;
+  private static log: File | null = null;
 
   public static banner() {
     this.shell
@@ -72,34 +73,38 @@ export class Output {
     filter: boolean,
   ) {
     if (verbose && !this.verbose) return;
-
     if (buffer === null) return;
 
     const filterExpression = (l: string) =>
       filter === false ||
-      l.length === 0 ||
+      l.trim().length === 0 ||
       Output.filter === null ||
       Output.filter.test(l);
 
+    let text = '';
     if (this.indent) {
       if (buffer.endsWith('\n')) {
         const lines = buffer.slice(0, buffer.length - 1).split('\n');
         const fixed = lines
           .filter(filterExpression)
           .join(`\r\n${Output.yellow('| ')}`);
-        send(['frida:stderr', `${Output.yellow('| ')}${fixed}\r\n`]);
+        text = `${Output.yellow('| ')}${fixed}\r\n`;
       } else {
         const lines = buffer.split('\n');
         const fixed = lines
           .filter(filterExpression)
           .join(`\r\n${Output.yellow('| ')}`);
-        send(['frida:stderr', `${Output.yellow('| ')}${fixed}`]);
+        text = `${Output.yellow('| ')}${fixed}`;
       }
     } else {
       const lines = buffer.split('\n');
-      const fixed = lines.filter(filterExpression).join(`\r\n`);
-      send(['frida:stderr', fixed]);
+      text = lines.filter(filterExpression).join(`\r\n`);
+    }
+
+    if (this.log !== null) {
+      this.log.write(text);
     }
+    send(['frida:stderr', text]);
   }
 
   public static clearLine() {
@@ -155,4 +160,18 @@ export class Output {
   public static isFiltered() {
     return this.filter !== null;
   }
+
+  public static setLog(log: string) {
+    this.log = new File(log, 'w');
+  }
+
+  public static clearLog() {
+    if (this.log !== null) {
+      const pos = this.log.tell();
+      Output.writeln(`Wrote  ${Output.blue(pos.toString())} bytes to log.`);
+      this.log.flush();
+      this.log.close();
+      this.log = null;
+    }
+  }
 }