src/init/shell.c


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#include <init/shell.h>
#include <init/stdlib.h>
#include <shared/syscalls.h>

#define PROMPT "$ "

static int tty_fd = 0; // TODO put in stdlib

static int readline(char *buf, size_t max) {
	char c;
	size_t pos = 0;
	while (_syscall_read(tty_fd, &c, 1, 0)) {
		switch (c) {
			case '\b':
			case 0x7f:
				/* for some reason backspace outputs 0x7f (DEL) */
				if (pos != 0) {
					printf("\b \b");
					pos--;
				}
				break;
			case '\r':
				printf("\n");
				buf[pos++] = '\0';
				return pos;
			default:
				if (pos < max) {
					_syscall_write(tty_fd, &c, 1, 0);
					buf[pos] = c;
					pos++;
				}
		}
	}
	return -1; // error
}

void shell_loop(void) {
	static char cmd[256];
	for (;;) {
		printf(PROMPT);
		readline(cmd, 256);
		printf("  %s\n", cmd);
	}
}