simple shell

gceylan_simple_shell.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <libgen.h>
#include <readline/readline.h>
#include <readline/history.h>

#define ARGV_SIZE 1<<16
#define TRUE 1
#define FALSE 0

const char *history = "/.gceylan_sheel_history/history";
const int history_count = 20;

void parse_args(char *buffer, char **args, int args_size, int *nargs)
{
	char *buffer_args[args_size];
	char **p;
	char *wbuf;
	int i, j;

	wbuf = buffer;
	buffer_args[0] = buffer;
	args[0] = buffer;
	i = 0, j = 0;

	for (p = buffer_args; (*p = strsep(&wbuf, " \n\t")) != NULL; )
	{
		if ((*p != '\0') && (++p >= &buffer_args[args_size]))
			break;
	}

	for (i = 0, j = 0; buffer_args[i] != NULL; i++)
	{
		if (strlen(buffer_args[i]) > 0)
			args[j++] = buffer_args[i];
	}

	*nargs = j;
	args[j] = NULL;
}

int main(void)
{
	char *input, shell_prompt[100];
	rl_bind_key('\t', rl_complete);
	char *argv[ARGV_SIZE];

	int ret;
	int argc;

	pid_t pid;


	// readline entegre kodları
	char *cp, *history_filename;
	char tmp_filename[200];
	struct stat st;

	using_history(); /* initial readline history */
	rl_initialize(); /* initial readline */
	stifle_history(history_count); /* maximum of 20 history commands */
	rl_inhibit_completion = TRUE;
	strcpy(tmp_filename, getenv("HOME"));
	strcat(tmp_filename, history);
	history_filename = strdup(tmp_filename);

	if (!history_filename)
	{
		perror("strdup");
		exit(EXIT_FAILURE);
	}

	cp = dirname(tmp_filename);
	/* Create '$HOME/.readline' directory if it doesn' t exist */
	if (lstat(cp, &st))
	{
		if (mkdir(cp, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH))
		{
			perror("mkdir");
			exit(EXIT_FAILURE);
		}
	}
	else if (!S_ISDIR(st.st_mode))
	{
		printf("Fatal - File %s exists and is not a directory\n", cp);
		exit(EXIT_FAILURE);
	}

	if (!read_history(history_filename))
		printf("Using the %d last commands you entered\n", history_count);
	else
		printf("History file %s created\n", history_filename);

	while (TRUE)
	{
		snprintf(shell_prompt, sizeof(shell_prompt), "%s:%s $ ", getenv("USER"), getcwd(NULL, 1024));
		input = readline(shell_prompt);

		// EOF
		if (!input) break;

		if (*input)
			add_history(input);

		parse_args(input, argv, ARGV_SIZE, &argc);

		if (argc == 0) continue;
		if (!strcmp(argv[0], "exit")) break;
		
		pid = fork();
		if (pid)
			pid = wait(&ret);
		else if (pid == -1)
		{
			perror("fork");
			exit(EXIT_FAILURE);
		}
		else
		{
			if (execvp(argv[0], argv))
			{
				perror("execvp");
				exit(EXIT_FAILURE);
			}
		}

		free(input);
	}

	free(input);
	printf("Exiting...\n");

	if (write_history(history_filename))
	{
		perror("write_history");
		exit(EXIT_FAILURE);
	}

	free(history_filename);
	return EXIT_SUCCESS;
}