p7utils/src/p7os/args.c

/* ************************************************************************** */
/*                                       _____           _                    */
/*  args.c                              |_   _|__  _   _| |__   ___ _   _     */
/*  | Project: p7os                       | |/ _ \| | | | '_ \ / _ \ | | |    */
/*                                        | | (_) | |_| | | | |  __/ |_| |    */
/*  By: thomas <thomas@touhey.fr>         |_|\___/ \__,_|_| |_|\___|\__, |.fr */
/*  Last updated: 2016/09/28 06:00:10                               |___/     */
/*                                                                            */
/* ************************************************************************** */
#include "main.h"
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <errno.h>

/* ************************************************************************** */
/*  Help and version messages                                                 */
/* ************************************************************************** */
/* The version message - that's when the President comes in */
static const char version_message[] =
QUOTE(BIN) " - from " QUOTE(NAME) " v" QUOTE(VERSION) " (licensed under GPLv2)\n"
"Maintained by " QUOTE(MAINTAINER) ".\n"
"\n"
"This is free software; see the source for copying conditions.\n"
"There is NO warranty; not even for MERCHANTABILITY or\n"
"FITNESS FOR A PARTICULAR PURPOSE.";

/* Main help message */
static const char help_main[] =
"Usage: " QUOTE(BIN) " [--version|-v] [--help|-h] [--device /dev/omg0]\n"
"            <subcommand> [options...]\n"
"\n"
"Subcommands you can use are :\n"
"   prepare       Prepare server on distant machine\n"
"   get           Get the OS image\n"
"\n"
"All subcommands that aren't \"prepare\" require \"prepare\" to be run\n"
"before them.\n"
"\n"
"General options:\n"
"  -h, --help        Display the help page of the (sub)command and quit.\n"
"  -v, --version     Display the version message and quit.\n"
"  --device dev      The calculator device (usually /dev/ttyUSBx).\n"
"                    By default, will use the first appropriate device found.\n"
"\n"
"Type \"" QUOTE(BIN) " <subcommand> --help\" for some help about a subcommand.\n"
"Report bugs to " QUOTE(MAINTAINER) ".";

/* Subcommands help messages footer */
#define FOOT \
	"\nType \"" QUOTE(BIN) " --help\" for other subcommands and general options."

/* Help message for prepare subcommand  */
static const char help_prepare[] =
"Usage: p7os prepare\n"
"Send the P7 server on the calculator for further operations.\n"
"This must be used before any other p7os operation.\n"
FOOT;

/* Help message for get subcommand */
static const char help_get[] =
"Usage: p7os get [-o <os.bin>]\n"
"Get the calculator OS image.\n"
"You must have \"p7os prepare\"-ed before.\n"
"\n"
"Options are :\n"
"  -o <os.bin>    Where to store the image (default is \"os.bin\")\n"
FOOT;

/* ************************************************************************** */
/*  Main function                                                             */
/* ************************************************************************** */
/* Help macro */
#define sub_init(CMD, NARGS) { \
	if (help || pc != (NARGS)) { \
		puts(help_##CMD); \
		return (1); \
	} \
}

/**
 *	parse_args:
 *	Args parsing main function.
 *
 *	Based on my very first experiment with getopt.
 *
 *	@arg	ac		the arguments count
 *	@arg	av		the arguments values
 *	@arg	args	the parsed args pointer
 *	@return			if has been parsed successfully
 */

int parse_args(int ac, char **av, args_t *args)
{
	/* initialize args */
	*args = (args_t){
		.device = NULL,
		.local = NULL, .localpath = NULL
	};

	/* define options */
	const char short_options[] = "hvo:";
	const struct option long_options[] = {
		{"help", no_argument, NULL, 'h'},
		{"version", no_argument, NULL, 'v'},
		{"device", required_argument, NULL, 'p'},
		{"output", required_argument, NULL, 'o'},
		{NULL, 0, NULL, 0}
	};

	/* get all options */
	int c; opterr = 0;
	int help = 0, version = 0;
	const char *s_out = "os.bin";
	while ((c = getopt_long(ac, av, short_options, long_options, NULL)) != -1) {
		switch (c) {
		/* help */
		case 'h': help = 1; break;
		/* version */
		case 'v': version = 1; break;
		/* device */
		case 'p': args->device = optarg; break;
		/* output */
		case 'o': s_out = optarg; break;

		/* error */
		case '?':
			if (optopt == 'o')
				log("-o, --output: expected an argument\n");
			else if (optopt == 'p')
				log("--device: expected an argument\n");
			else
				break;
			return (1);
		}
	}

	/* check for version */
	if (version) {
		puts(version_message);
		return (1);
	}

	/* get non-option arguments (subcommand and parameters) */
	int pc = ac - optind;
	char **pv = &av[optind];
	char *sub = pc ? pv[0] : NULL;
	pc--; pv++;

	/* subcommand. */
	char fpmode[2] = "r";
	if (!sub || !strcmp(sub, "help")) {
		puts(help_main);
		return (1);
	} else if (!strcmp(sub, "version")) {
		puts(version_message);
		return (1);
	} else if (!strcmp(sub, "prepare")) {
		sub_init(prepare, 0)
	} else if (!strcmp(sub, "get")) {
		sub_init(get, 0)
		args->localpath = s_out;
		fpmode[0] = 'w';
	} else {
		log("Unknown subcommand '%s'.\n", sub);
		return (1);
	}

	/* open destination file */
	if (args->localpath) {
		args->local = fopen(args->localpath, fpmode);
		if (!args->local) {
			log("Could not open local file: '%s'\n", strerror(errno));
			return (1);
		}
	}

	/* everything went well :) */
	return (0);
}