metal-cos/bin/shell/shell.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

// Castor Only
#include <syscall.h>
#include <sys/dirent.h>

#define SHELL_MAX_ARGS 5
#define SHELL_MAX_LINE 256

void DispatchCommand(char *buf);

int
main(int argc, const char *argv[])
{
    char buf[256];

    printf("System Shell\n");

    while (1) {
	fputs("Shell> ", stdout);
	fgets(buf, sizeof(buf), stdin);

	DispatchCommand(buf);
    }
}

void
Cmd_Help(int argc, const char *argv[])
{
    printf("cat        Print file\n");
    printf("bkpt       Trigger a kernel breakpoint\n");
    printf("date       Print current date and time\n");
    printf("echo       Echo arguments\n");
    printf("exit       Exit shell\n");
    printf("help       Display the list of commands\n");
    printf("ls         List files in a directory\n");
    printf("spawn      Spawn a process\n");
}

void
Cmd_Echo(int argc, const char *argv[])
{
    int i;

    for (i = 1; i < argc; i++)
    {
	printf("%s ", argv[i]);
    }
    printf("\n");
}

void
Cmd_List(int argc, const char *argv[])
{
    int fd;
    int status;
    uintptr_t offset = 0;

    if (argc != 2) {
	fputs("Requires an argument\n", stdout);
	return;
    }

    fd = OSOpen(argv[1], 0);
    if (fd < 0) {
	fputs("Cannot open directory\n", stdout);
	return;
    }

    while (1) {
	struct dirent de;

	status = OSReadDir(fd, (char *)&de, sizeof(de), &offset);
	if (status == 0) {
	    break;
	}
	if (status < 0) {
	    fputs("Error\n", stdout);
	    break;
	}

	printf("%s\n", de.d_name);
    }
}

void
Cmd_Cat(int argc, const char *argv[])
{
    int i;
    int status, fd;
    struct stat sb;
    char buf[256];

    if (argc != 2) {
	fputs("Requires an argument\n", stdout);
	return;
    }

    status = OSStat(argv[1], &sb);
    if (status != 0) {
	fputs("Cannot stat file\n", stdout);
	return;
    }
    fd = OSOpen(argv[1], 0);
    for (i = 0; i < sb.st_size; i += 256) {
	int len = (sb.st_size - i > 256) ? 256 : (sb.st_size - i);

	OSRead(fd, &buf, i, len);
	OSWrite(1, &buf, 0, len);
    }
}

void
Cmd_Date(int argc, const char *argv[])
{
    time_t t = time(NULL);
    fputs(ctime(&t), stdout);
}

void
Cmd_Hexdump(int argc, const char *argv[])
{
}

void
Cmd_Spawn(int argc, const char *argv[])
{
    int fd;
    uint64_t status;
    uintptr_t offset = 0;

    if (argc != 2) {
	fputs("Requires an argument\n", stdout);
	return;
    }

    status = OSSpawn(argv[1]);
    // XXX: check errors
    OSWait(status);
}

void
DispatchCommand(char *buf)
{
    int i;
    int argc;
    char *argv[SHELL_MAX_ARGS];
    char *nextArg;

    // Remove newline
    for (i = 0; buf[i] != 0; i++) {
	if (buf[i] == '\n') {
	    buf[i] = '\0';
	    break;
	}
    }

    // parse input
    argv[0] = buf;
    for (argc = 1; argc < SHELL_MAX_ARGS; argc++) {
        nextArg = strchr(argv[argc - 1], ' ');
        if (nextArg == NULL)
        {
            break;
        }

        *nextArg = '\0';
        argv[argc] = nextArg + 1;
    }

    // execute command
    if (strcmp(argv[0], "help") == 0) {
	Cmd_Help(argc, (const char **)argv);
    } else if (strcmp(argv[0], "bkpt") == 0) {
	asm volatile("int3");
    } else if (strcmp(argv[0], "cat") == 0) {
	Cmd_Cat(argc, (const char **)argv);
    } else if (strcmp(argv[0], "date") == 0) {
	Cmd_Date(argc, (const char **)argv);
    } else if (strcmp(argv[0], "echo") == 0) {
	Cmd_Echo(argc, (const char **)argv);
    } else if (strcmp(argv[0], "exit") == 0) {
	exit(0);
    } else if (strcmp(argv[0], "ls") == 0) {
	Cmd_List(argc, (const char **)argv);
    } else if (strcmp(argv[0], "spawn") == 0) {
	Cmd_Spawn(argc, (const char **)argv);
    } else if (strcmp(argv[0], "#") == 0) {
	// Ignore comments
    } else if (buf[0] != '\0') {
	printf("Unknown command '%s'\n", buf);
    }
}