add optional support to replace argv[0] (fixes #472)

src/interfaces.ts

@@ -115,6 +115,7 @@ interface IBasePtyForkOptions {
 export interface IPtyForkOptions extends IBasePtyForkOptions {
   uid?: number;
   gid?: number;
+  argv0?: string;
 }
 
 export interface IWindowsPtyForkOptions extends IBasePtyForkOptions {

src/native.d.ts

@@ -19,7 +19,7 @@ interface IWinptyNative {
 }
 
 interface IUnixNative {
-  fork(file: string, args: string[], parsedEnv: string[], cwd: string, cols: number, rows: number, uid: number, gid: number, useUtf8: boolean, helperPath: string, onExitCallback: (code: number, signal: number) => void): IUnixProcess;
+  fork(file: string, args: string[], parsedEnv: string[], cwd: string, cols: number, rows: number, uid: number, gid: number, useUtf8: boolean, helperPath: string, onExitCallback: (code: number, signal: number) => void, argv0: string): IUnixProcess;
   open(cols: number, rows: number): IUnixOpenProcess;
   process(fd: number, pty?: string): string;
   resize(fd: number, cols: number, rows: number): void;

src/unix/pty.cc

@@ -158,7 +158,7 @@ pty_posix_spawn(char** argv, char** env,
 NAN_METHOD(PtyFork) {
   Nan::HandleScope scope;
 
-  if (info.Length() != 11 ||
+  if (info.Length() != 12 ||
       !info[0]->IsString() ||
       !info[1]->IsArray() ||
       !info[2]->IsArray() ||
@@ -169,9 +169,10 @@ NAN_METHOD(PtyFork) {
       !info[7]->IsNumber() ||
       !info[8]->IsBoolean() ||
       !info[9]->IsString() ||
-      !info[10]->IsFunction()) {
+      !info[10]->IsFunction() ||
+      !info[11]->IsString()) {
     return Nan::ThrowError(
-        "Usage: pty.fork(file, args, env, cwd, cols, rows, uid, gid, utf8, helperPath, onexit)");
+        "Usage: pty.fork(file, args, env, cwd, cols, rows, uid, gid, utf8, helperPath, onexit, argv0)");
   }
 
   // file
@@ -247,19 +248,23 @@ NAN_METHOD(PtyFork) {
   // helperPath
   Nan::Utf8String helper_path(info[9]);
 
+  // argv0
+  Nan::Utf8String argv0(info[11]);
+
   pid_t pid;
   int master;
 #if defined(__APPLE__)
   int argc = argv_->Length();
-  int argl = argc + 4;
+  int argl = argc + 5;
   char **argv = new char*[argl];
   argv[0] = strdup(*helper_path);
   argv[1] = strdup(*cwd_);
   argv[2] = strdup(*file);
+  argv[3] = strdup(*argv0);
   argv[argl - 1] = NULL;
   for (int i = 0; i < argc; i++) {
     Nan::Utf8String arg(Nan::Get(argv_, i).ToLocalChecked());
-    argv[i + 3] = strdup(*arg);
+    argv[i + 4] = strdup(*arg);
   }
 
   int err = -1;
@@ -276,7 +281,7 @@ NAN_METHOD(PtyFork) {
   int argc = argv_->Length();
   int argl = argc + 2;
   char **argv = new char*[argl];
-  argv[0] = strdup(*file);
+  argv[0] = strdup(*argv0);
   argv[argl - 1] = NULL;
   for (int i = 0; i < argc; i++) {
     Nan::Utf8String arg(Nan::Get(argv_, i).ToLocalChecked());
@@ -342,7 +347,8 @@ NAN_METHOD(PtyFork) {
       {
         char **old = environ;
         environ = env;
-        execvp(argv[0], argv);
+        char* file_ = strdup(*file);
+        execvp(file_, argv);
         environ = old;
         perror("execvp(3) failed.");
         _exit(1);

src/unix/spawn-helper.cc

@@ -12,7 +12,7 @@ int main (int argc, char** argv) {
 
   char *cwd = argv[1];
   char *file = argv[2];
-  argv = &argv[2];
+  argv = &argv[3];
 
   if (strlen(cwd) && chdir(cwd) == -1) {
     _exit(1);

src/unixTerminal.test.ts

@@ -365,6 +365,31 @@ if (process.platform !== 'win32') {
           }
         });
       });
+      it('should default argv0 to file', (done) => {
+        const term = new UnixTerminal('/bin/sh',
+          [ '-c', 'echo $0' ]);
+        let argv0 = '';
+        term.on('data', (data) => {
+          argv0 = argv0.concat(data);
+        });
+        term.on('exit', () => {
+          assert.strictEqual(argv0.trim(), '/bin/sh');
+          done();
+        });
+      });
+      it('should allow an alternate argv0', (done) => {
+        const term = new UnixTerminal('/bin/sh',
+          [ '-c', 'echo $0' ],
+          { argv0: 'alternate' });
+        let argv0 = '';
+        term.on('data', (data) => {
+          argv0 = argv0.concat(data);
+        });
+        term.on('exit', () => {
+          assert.strictEqual(argv0.trim(), 'alternate');
+          done();
+        });
+      });
     });
   });
 }

src/unixTerminal.ts

@@ -110,8 +110,10 @@ export class UnixTerminal extends Terminal {
       this.emit('exit', code, signal);
     };
 
+    const argv0 = opt.argv0 ?? file;
+
     // fork
-    const term = pty.fork(file, args, parsedEnv, cwd, this._cols, this._rows, uid, gid, (encoding === 'utf8'), helperPath, onexit);
+    const term = pty.fork(file, args, parsedEnv, cwd, this._cols, this._rows, uid, gid, (encoding === 'utf8'), helperPath, onexit, argv0);
 
     this._socket = new PipeSocket(term.fd);
     if (encoding !== null) {

typings/node-pty.d.ts

@@ -83,6 +83,12 @@ declare module 'node-pty' {
      */
     uid?: number;
     gid?: number;
+
+    /**
+     * Alternate argv[0] to use instead of the file being launched. Can be used to launch a shell
+     * as a login shell, e.g. using `"-sh"` when launching /bin/sh.
+     */
+    argv0?: string;
   }
 
   export interface IWindowsPtyForkOptions extends IBasePtyForkOptions {