Added rpi gpio program.

[utils.git] / nextep.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <libgen.h>
#include <dirent.h>
#include <errno.h>
#include <sys/stat.h>

static int ensuredir(char *base, char *dir)
{
    if(access(dir, X_OK)) {
	if((mkdir(base, 0777) && (errno != EEXIST)) || mkdir(dir, 0777))
	    return(1);
    }
    return(0);
}

static void checkempty(char *dir)
{
    DIR *dh;
    int empty;
    struct dirent *de;
    
    if((dh = opendir(dir)) == NULL)
	return;
    empty = 1;
    while((de = readdir(dh)) != NULL) {
	if(de->d_name[0] != '.') {
	    empty = 0;
	    break;
	}
    }
    closedir(dh);
    if(empty)
	rmdir(dir);
}

static void usage(FILE *out)
{
    fprintf(out, "usage: nextep [-h] [-f FILE] [-s SET-VALUE] [DIR]\n");
}

int main(int argc, char **argv)
{
    int c;
    char buf[1024], dbuf[1024], *p;
    char *file, *value, *dir;
    char base[1024], fpath[1024];
    FILE *fp;
    
    file = "nextep";
    value = NULL;
    while((c = getopt(argc, argv, "hf:s:")) >= 0) {
	switch(c) {
	case 'f':
	    file = optarg;
	    break;
	case 's':
	    value = optarg;
	    break;
	case 'h':
	    usage(stdout);
	    exit(0);
	default:
	    usage(stderr);
	    exit(1);
	}
    }
    if(optind < argc) {
	if(chdir(argv[optind])) {
	    fprintf(stderr, "nextep: %s: %s\n", argv[optind], strerror(errno));
	    exit(1);
	}
	optind++;
    }
    if(!getcwd(dbuf, sizeof(dbuf))) {
	fprintf(stderr, "nextep: getcwd: %s\n", strerror(errno));
	exit(1);
    }
    dir = basename(dbuf);
    if((p = getenv("HOME")) == NULL) {
	fprintf(stderr, "nextep: $HOME is not set\n");
	exit(1);
    }
    snprintf(buf, sizeof(buf), "%s/.nextep", p);
    snprintf(base, sizeof(base), "%s/%s", buf, dir);
    snprintf(fpath, sizeof(fpath), "%s/%s", base, file);
    if(value == NULL) {
	if((fp = fopen(fpath, "r")) == NULL) {
	    if(errno != ENOENT) {
		fprintf(stderr, "nextep: %s: %s\n", fpath, strerror(errno));
		exit(1);
	    }
	} else {
	    while(fgets(buf, sizeof(buf), fp) != NULL)
		printf(buf);
	    fclose(fp);
	}
    } else if(!*value) {
	if(unlink(fpath) && (errno != ENOENT)) {
	    fprintf(stderr, "nextep: %s: %s\n", fpath, strerror(errno));
	    exit(1);
	}
	checkempty(base);
    } else {
	if(ensuredir(buf, base)) {
	    fprintf(stderr, "nextep: %s: %s\n", base, strerror(errno));
	    exit(1);
	}
	if((fp = fopen(fpath, "w")) == NULL) {
	    fprintf(stderr, "nextep: %s: %s\n", fpath, strerror(errno));
	    exit(1);
	}
	fprintf(fp, "%s\n", value);
	fclose(fp);
    }
    return(0);
}

/*
 * Local Variables:
 * compile-command: "gcc -Wall -g -o nextep nextep.c"
 * End:
 */