Update userspace

apps/base/fsh/fsh.c

@@ -1,7 +1,160 @@
 #include <stdio.h>
+#include <stdlib.h>
 
-int main(int argc, char *argv[], char *envp[])
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#define _GNU_SOURCE
+#include <signal.h>
+#include <termios.h>
+#define _POSIX_SOURCE
+#include <string.h>
+
+#define MAX_COMMAND_LENGTH 1024
+#define MAX_ARGS 10
+
+void DisableInputBuffering()
 {
-	printf("Hello, world!\n");
+	struct termios tty_attr;
+	tcgetattr(STDIN_FILENO, &tty_attr);
+	tty_attr.c_lflag &= ~(ICANON | ECHO);
+	tcsetattr(STDIN_FILENO, TCSANOW, &tty_attr);
+}
+
+void EnableInputBuffering()
+{
+	struct termios tty_attr;
+	tcgetattr(STDIN_FILENO, &tty_attr);
+	tty_attr.c_lflag |= ICANON | ECHO;
+	tcsetattr(STDIN_FILENO, TCSANOW, &tty_attr);
+}
+
+void ReadLine(char *Buffer, size_t BufferSize)
+{
+	size_t index = 0;
+	int c;
+	while (1)
+	{
+		c = getchar();
+		if (c == EOF || c == '\n')
+		{
+			Buffer[index] = '\0';
+			break;
+		}
+		else if (c == 127 || c == 8) // Backspace
+		{
+			if (index > 0)
+			{
+				printf("\b \b");
+				index--;
+			}
+		}
+		else if (c == 4) // Ctrl + D
+		{
+			if (index == 0)
+				kill(getpid(), SIGQUIT);
+			else
+				putchar('\a');
+		}
+		else
+		{
+			if (index < BufferSize - 1)
+			{
+				putchar(c);
+				Buffer[index] = (char)c;
+				index++;
+			}
+		}
+	}
+}
+
+void ExecuteCommand(char *command)
+{
+	char *args[MAX_ARGS];
+	int i = 0;
+
+	char *token = strtok(command, " ");
+	while (token != NULL && i < MAX_ARGS - 1)
+	{
+		args[i++] = token;
+		token = strtok(NULL, " ");
+	}
+	args[i] = NULL;
+
+	pid_t pid = fork();
+	if (pid == 0)
+	{
+		execvp(args[0], args);
+		perror("execvp");
+		exit(EXIT_FAILURE);
+	}
+	else if (pid > 0)
+		wait(NULL);
+	else
+	{
+		perror("fork");
+		exit(EXIT_FAILURE);
+	}
+}
+
+void HandleSignal(int signal)
+{
+	if (signal == SIGQUIT)
+	{
+		EnableInputBuffering();
+		printf("\n");
+		exit(EXIT_SUCCESS);
+	}
+	else if (signal == SIGINT)
+	{
+		putchar('\n');
+	}
+	else if (signal == SIGHUP)
+	{
+		EnableInputBuffering();
+		exit(EXIT_SUCCESS);
+	}
+	else if (signal == SIGCHLD)
+		wait(NULL);
+	else if (signal == SIGSEGV)
+	{
+		printf("Segmentation fault\n");
+		while (1)
+			sleep(1000);
+	}
+	else
+	{
+		printf("Signal %s(%d) received\n",
+			   strsignal(signal), signal);
+	}
+}
+
+int main()
+{
+	char command[MAX_COMMAND_LENGTH];
+	for (int i = 0; i < NSIG; ++i)
+		signal(i, HandleSignal);
+
+	char hostname[256];
+	gethostname(hostname, sizeof(hostname));
+
+	while (1)
+	{
+		printf("\033[1;32m");
+		printf("┌──(%s@%s)-[%s]\n", getenv("USER"), hostname, getenv("PWD"));
+		printf("└$ ");
+		printf("\033[0m");
+
+		DisableInputBuffering();
+		ReadLine(command, sizeof(command));
+		EnableInputBuffering();
+		putchar('\n');
+
+		if (strcmp(command, "exit") == 0)
+			break;
+
+		ExecuteCommand(command);
+	}
+
 	return 0;
 }