shell.c

#include <string.h>
#include <ctype.h>

#include "shell.h"

struct shell_cmd {
	const char *cmd_name;
	const char *cmd_help;
	void (*cmd_fn)(struct shell_struct *s, int argc, char *const argv[]);
};

static struct shell_struct sh;

extern void ip_cmd_main(struct shell_struct *s, int argc, char *const argv[]);
extern void hwaddr_main(struct shell_struct *s, int argc, char *const argv[]);
extern void route_main(struct shell_struct *s, int argc, char *const argv[]);
extern void nc_main(struct shell_struct *s, int argc, char *const argv[]);

static const struct shell_cmd cmd_list[] = {
	{
		.cmd_name = "ip",
		.cmd_help = "set/get interface IP address",
		.cmd_fn   = ip_cmd_main
	},
	{
		.cmd_name = "hwaddr",
		.cmd_help = "set/get mac address",
		.cmd_fn   = hwaddr_main
	},
	{
		.cmd_name = "route",
		.cmd_help = "show/manipulate the routing tables",
		.cmd_fn   = route_main
	},
	{
		.cmd_name = "nc",
		.cmd_help = "arbitrary TCP and UDP connections and listens",
		.cmd_fn   = nc_main
	},
	{ /* Terminating entry */ }
};

static void show_help(void)
{
	const struct shell_cmd *c;

	for (c = &cmd_list[0]; c->cmd_name; c++) {
		if (c->cmd_help)
			fprintf(stdout, "%-10s - %s\n", c->cmd_name, c->cmd_help);
	}
}

static void shell_run_cmd(int argc, char *const argv[])
{
	const struct shell_cmd *cmd;
	const char *argv0 = argv[0];

	if (!strcmp(argv0, "help") || *argv0 == '?')
		return show_help();

	for (cmd = &cmd_list[0]; cmd->cmd_name; cmd++) {
		if (!strcmp(argv0, cmd->cmd_name))
			return cmd->cmd_fn(&sh, argc, argv);
	}

	fprintf(stderr, "Command \"%s\" is unknown, try \"help\".\n", argv0);
}

static void __attribute__ ((unused))
arg_print(int argc, const char *argv[])
{
	int i;

	printf("argc: %d\n", argc);
	for (i = 0; i < argc; ++i)
		printf("%s\n", argv[i]);
}

void shell_display_prompt(const struct shell_struct *sh)
{
	fprintf(stdout, "%s", sh->prompt);
	fflush(stdout);
}

#define ARGV_SIZE 8
#define ARGV_MAX (ARGV_SIZE - 1)

static int shell_process_input(struct shell_struct *ss)
{
	char *argv[ARGV_SIZE], buf[1024], *cp;
	int argc;

	if (!fgets(buf, sizeof(buf), ss->fp)) {
		fprintf(stdout, "\n");
		return 0;
	}

	argc = 0;
	cp = buf;

	/* Skip over any whitespace at start of string */
	while (isspace(*cp))
		cp++;

	while (*cp && argc < ARGV_MAX) {
		argv[argc++] = cp++;

		/* Skip over alpha-numeric chars to get next arg */
		while (isalnum(*cp) || ispunct(*cp))
			cp++;

		*cp++ = '\0';

		while (isspace(*cp))
			cp++;
	}

	argv[argc] = NULL;
	if (argc)
		shell_run_cmd(argc, argv);
	if (ss->process_input == shell_process_input)
		shell_display_prompt(ss);

	return 1;
}

struct shell_struct *shell_init(FILE *fp, const char *prompt)
{
	sh.fp = stdin;
	sh.process_input = shell_process_input;
	sh.prompt = prompt;
	shell_display_prompt(&sh);

	return &sh;
}