/*
 * program to print information about named user(s)
 * demonstrates mapping user name (etc.) and date
 *
 * Matt Bishop, bishop@cs.ucdavis.edu	11/9/96
 */
#include <ctype.h>
#include <stdio.h>
#include <grp.h>
#include <pwd.h>
#include <sys/time.h>
#include <time.h>

/*
 * forward declarations
 */
void setgrent(void);	/* initialize group file -- not in grp.h!!! */
void endgrent(void);	/* clean up group file -- not in grp.h!!! */
int gettimeofday(struct timeval *, struct timezone *);	/* get time of day */

/*
 * prints the current time of day
 */
int prdate(void)
{
	struct timeval tod;	/* time of day */
	struct timezone tz;	/* time zone */
	char *atod;		/* date as a string */

	/*
	 * get the time of day
	 */
	if (gettimeofday(&tod, &tz) < 0)
		return(1);
	/*
	 * convert it to a string and print it
	 */
	if ((atod = ctime((time_t *)&tod.tv_sec)) == NULL)
		atod = "Time not available\n";
	printf("%s", atod);
	return(0);
}

/*
 * print secondary group list
 * this is a list of groups the user is in
 * name is name of user, gid is his/her GID
 * if empty list, print *none*
 */
void prsgid(char *name, int gid)
{
	register struct group *gp;	/* points to group info */
	register char **p;		/* walks user list of group */
	register int count = 0;		/* how many groups printed */

	/*
	 * initialize group file for scan
	 */
	setgrent();

	/*
	 * loop through groups, looking for this user
	 * in its member list
	 */
	while ((gp = getgrent()) != NULL){
		for(p = gp->gr_mem; *p; p++)
			if (strcmp(*p, name) == 0){
				/* bingo! */
				printf(" %s(%d)", gp->gr_name, gp->gr_gid);
				count++;
				break;
			}
	}

	/*
	 * clean up and leave
	 */
	endgrent();
	if (count == 0)
		printf(" *none*");
}

/*
 * given a GID gid, print the group name or *unknown* if none
 * also the GID.
 */
void grname(int gid)
{
	struct group *gp;		/* points to group info */

	/*
	 * if you find it, print it; else say *unknown*
	 */
	if ((gp = getgrgid(gid)) == NULL)
		printf("*unknown*(%d)\n", gid);
	else
		printf("%s(%d)\n", gp->gr_name, gid);
}
		
/*
 * print user information about user name; if name is number,
 * take as UID
 */
void getuinfo(char *name)
{
	register int n = 0;	/* UID if name is UID */
	register char *s;	/* used to check if name is UID or name */
	struct passwd *pw;	/* points to user info */

	/*
	 * get the user information structure
	 */
	for(s = name; *s && isdigit(*s); s++)
		n = n * 10 + *s - '0';
	if (!*s){
		/* it's an integer */
		pw = getpwuid(n);
	}
	else{
		/* it's not an integer */
		pw = getpwnam(name);
	}

	/*
	 * check for bad name/UID
	 */
	if (pw == NULL){
		printf("%s: unknown %s\n", name, *s ? "name" : "UID");
		return;
	}

	/*
	 * now dump the user information
	 */
	printf("user name: %s\n", pw->pw_name);
	printf("hashed password: %s\n", pw->pw_passwd);
	printf("UID: %d\n", pw->pw_uid);
	/* do the principle GID as groupname(gid) */
	printf("principle GID: ");
	grname(pw->pw_gid);
	/* do the secondary GID as a list of groupname(gid)s */
	printf("secondary GIDs:");
	prsgid(pw->pw_name, pw->pw_gid);
	putchar('\n');
	printf("GECOS field: %s\n", pw->pw_gecos);
	printf("home directory: %s\n", pw->pw_dir);
	printf("login shell: %s\n", pw->pw_shell);
}

/*
 * the main routine
 */
int main(int argc, char *argv[])
{
	register int i;		/* used to walk argument list */

	/*
	 * print the date
	 */
	if (prdate()){
		perror(argv[0]);
		return(1);
	}
	/*
	 * print the user info one user at a time
	 * with a separating header
	 */
	for(i = 1; i < argc; i++){
		printf("========== %s ==========\n", argv[i]);
		getuinfo(argv[i]);
	}
	return(0);
}