More or less rewrote _PipeCommand() to be:

a) less error prone, and
b) easier on the eyes.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18573 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/tracker/zipomatic/ZipOMaticZipper.cpp

@@ -250,50 +250,66 @@ thread_id
 ZipperThread::_PipeCommand(int argc, const char** argv, int& in, int& out,
 	int& err, const char** envp)
 {
-	// This function written by Peter Folk <[email protected]>
+	// This function was originally written by Peter Folk <[email protected]>
 	// and published in the BeDevTalk FAQ
 	// http://www.abisoft.com/faq/BeDevTalk_FAQ.html#FAQ-209
 
+	thread_id thread;
+
 	// Save current FDs
-	int old_in = dup(0); 
+	int oldIn = dup(STDIN_FILENO);
-	int old_out = dup(1); 
+	int oldOut = dup(STDOUT_FILENO);
-	int old_err = dup(2); 
+	int oldErr = dup(STDERR_FILENO);
 
-	int filedes[2]; 
+	int inPipe[2], outPipe[2], errPipe[2];
 
-	/* Create new pipe FDs as stdin, stdout, stderr */ 
+	// Create new pipe FDs as stdin, stdout, stderr
-	pipe(filedes);
+	if (pipe(inPipe) < 0)
-	dup2(filedes[0], 0);
+		goto err1;
-	close(filedes[0]); 
+	if (pipe(outPipe) < 0)
-	in = filedes[1];  // Write to in, appears on cmd's stdin 
+		goto err2;
-	pipe(filedes);
+	if (pipe(errPipe) < 0)
-	dup2(filedes[1], 1);
+		goto err3;
-	close(filedes[1]); 
-	out = filedes[0]; // Read from out, taken from cmd's stdout 
-	pipe(filedes);
-	dup2(filedes[1], 2);
-	close(filedes[1]); 
-	err = filedes[0]; // Read from err, taken from cmd's stderr 
 
-	// "load" command. 
+	errno = 0;
-	thread_id ret = load_image(argc, argv, envp); 
+
-	// thread ret is now suspended. 
+	// replace old stdin/stderr/stdout
+	dup2(inPipe[0], STDIN_FILENO);
+	close(inPipe[0]);
+	dup2(outPipe[1], STDOUT_FILENO);
+	close(outPipe[1]);
+	dup2(errPipe[1], STDERR_FILENO);
+	close(errPipe[1]);
+
+	if (errno == 0) {
+		in = inPipe[1];		// Write to in, appears on cmd's stdin 
+		out = outPipe[0];	// Read from out, taken from cmd's stdout 
+		err = errPipe[0];	// Read from err, taken from cmd's stderr 
+
+		// execute command
+		thread = load_image(argc, argv, envp);
 
 		PRINT(("load_image() thread_id: %ld\n", ret));
+	} else
+		thread = errno;
 
 	// Restore old FDs
-	close(0); dup(old_in); close(old_in); 
+	close(STDIN_FILENO); dup(oldIn); close(oldIn);
-	close(1); dup(old_out); close(old_out); 
+	close(STDOUT_FILENO); dup(oldOut); close(oldOut);
-	close(2); dup(old_err); close(old_err); 
+	close(STDERR_FILENO); dup(oldErr); close(oldErr);
+	return thread;
 
-	// TODO:
+err3:
-	/*
+	close(outPipe[0]);
-	Theoretically I should do loads of error checking, but 
+	close(outPipe[1]);
-	the calls aren't very likely to fail, and that would 
+err2:
-	muddy up the example quite a bit.  YMMV.
+	close(inPipe[0]);
-	*/ 
+	close(inPipe[1]);
-
+err1:
-    return ret;
+	close(oldIn);
+	close(oldOut);
+	close(oldErr);
+	return errno;
 }