psh/src/main.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdarg.h>
#include <signal.h>
#include <string.h>
#include <limits.h>

#include "icmd.h"


#define INPUT_MAX_LEN 1024
#define PATH_MAX_LEN  4096

#define TOKENS_NUM_MAX 512
#define TOKENS_ARGS_SIZE 2048


char *g_tokens[TOKENS_NUM_MAX];
char g_args[TOKENS_ARGS_SIZE];


void
die(int status, char *format, ...)
{
        va_list args;

        va_start(args, format);
        if (status != 0)
                puts("Error: ");
        vprintf(format, args);
        if (status != 0)
                puts("! Exiting...");
        putchar('\n');
        if (status < 0)
                perror("Reason");
        exit(status);
        va_end(args);
}


void
sighup(int signal)
{
        die(1, "Parent process has ben killed");
}


void
sigint(int signal)
{
        die(0, "Caught ^C");
}


int
tokenize(char *input)
{
        char curr, prev = '\n';
        char **tokens = g_tokens;
        char *start = g_args;
        char *args = g_args;
        int real_input = 0;
        int argc = 0;

        while ((curr = *input++) != '\0')
        {
                if (curr == ' ' || curr == '\n')
                {
                        if (curr == prev || !real_input)
                                continue;

                        *tokens++ = start;
                        *args++ = '\0';
                        start = args;
                        argc++;

                        if (curr == '\n')
                                break;
                } else
                {
                        *args++ = curr;
                        real_input = 1;
                }

                prev = curr;
        }

        tokens = NULL;
        return argc;
}


int
main(int argc, char **argv)
{
        char input[INPUT_MAX_LEN];
        char cwd[PATH_MAX_LEN];
        int num_tokens, ret;

        signal(SIGINT, sigint);
        signal(SIGHUP, sighup);
        signal(SIGQUIT, sighup);

        for (;;)
        {
                if (getcwd(cwd, sizeof(cwd)) == NULL)
                        die(-1, "Could not get current directory");

                printf("[%s] ", cwd);

                if (!fgets(input, sizeof(input)-1, stdin))
                        die(0, "Caught ^D");

                if ((num_tokens = tokenize(input)) < 0)
                        die(1, "Could not parse tokens");

                if (num_tokens == 0)
                        continue;

                if ((ret = call_icmd(num_tokens, g_tokens) < 0))
                        puts("Internal command failed!");
        }
}