micro-utils/coreutils/chown.c

#include <pwd.h>
#include <grp.h>
#include <stdio.h>
#include <errno.h>
#include <dirent.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
unsigned int r_flag;

int (*chown_func)(const char *pathname, uid_t owner, gid_t group);
int (*stat_func)(const char *restrict pathname, struct stat *restrict statbuf);
long gid;
long uid;

int get_stat(const char *path, struct stat *stat_path) {
	if (stat_func(path, stat_path)) {
		fprintf(stderr, "chown: unable to stat %s: %s\n", path, strerror(errno));
		return 1;
	}

	return 0;
}

int change(const char *file) {
	struct stat old_file;
	if (get_stat(file, &old_file))
		return 1;

	if (chown_func(file, uid, gid) == 0) {
		struct stat new_file;
		if (get_stat(file, &new_file))
			return 1;

		if (old_file.st_gid != new_file.st_gid || old_file.st_uid != new_file.st_uid)
			return 0;

		fprintf(stderr, "chown: %s unchanged\n", file);
	}

	else
		fprintf(stderr, "chown: unable to stat %s: %s\n", file, strerror(errno));

	return 1;
}

int cntree(const char *dst) {
	change(dst);

	//Recurs
	return 0;
}

void get_owner(const char *arg) {
	char *group = strchr(arg, ':');

	unsigned int g_flag = 1;
	unsigned int u_flag = 1;
	if (group == arg)
		u_flag = 0;

	else if (!group)
		g_flag = 0;

	if (g_flag) {
		group[0] = '\0';
		group++;

		struct group *grp = getgrnam(group);
		if (!grp) {
			fprintf(stderr, "chown: invalid group: %s\n", group);
			exit(1);
		}

		gid = grp->gr_gid;
	}

	if (u_flag) {
		struct passwd *pwd = getpwnam(arg);
		if (!pwd) {
			fprintf(stderr, "chown: invalid user: %s\n", arg);
			exit(1);
		}

		uid = pwd->pw_gid;
	}
}

int main(const int argc, char **argv) {
	chown_func = lchown;
	stat_func = stat;

	int i;
	for (i = 1; i < argc; i++) {
		if (argv[i][0] != '-')
			break;

		else if (!strcmp(argv[i], "-r"))
			r_flag = 1;

		else if (!strcmp(argv[i], "-H")) {
			chown_func = chown;
			stat_func = stat;
		}

		else if (!strcmp(argv[i], "--help")) {
			printf("chown [-H (if a command line argument is a symbolic link)] [-r (recursive)] [owner]:[group] [file file2...]\n");
			return 0;
		}
	}

	if (argc - i == 0) {
		fprintf(stderr, "chown: missing operand\n");
		return 1;
	}

	gid = -1;
	uid = -1;
	get_owner(argv[i++]);

	if (argc - i == 0) {
		fprintf(stderr, "chown: missing operand\n");
		return 1;
	}

	int ret = 0;
	for (; i < argc; i++)
		if (cntree(argv[i]))
			ret = 1;

	return ret;
}