/*
	Recursive file directory of most recent files

    David Horton,
    Centre for Information Technology Research,
    University of Queensland
    horton@citr.uq.oz.au
*/
#include <time.h>
#include <stdio.h>
#ifdef msdos
#include <dos.h>
#else
#define _INCLUDE_POSIX_SOURCE
#endif
#include <sys/types.h>
#define _INCLUDE_HPUX_SOURCE	    /* HP/UX */
#define _INCLUDE_XOPEN_SOURCE	    /* HP/UX */
#define _INCLUDE_AES_SOURCE	    /* HP/UX */
#include <sys/stat.h>
#include <memory.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>

#define MF 2000
#define FNLEN 256
#define DISTANT 0x7fffffff

char	reverse = '\0';
char	st_time = 'm';	/* default to modification time */
int		uid = -1;		/* restrict to this uid */
int		gid = -1;		/* restrict to this gid */
char	nodate = '\0';	/* indicator that no date field should be printed */
char	device_mode	= '\0';	/* s means will be only one device, 
							   S means device set */
dev_t	device = 0;			/* the device number */
char	follow = '\0';	/* follow symbolic link mode */
char 	do_trace = '\0'; /* debug tracing */

struct context {        /* context we need to keep for a bigfile */
	long	lst_mtime;
	char    name[FNLEN];
	};

struct context  c[MF];

void big (long lst_mtime, char *fname) { /* see if this is a big file */
	int     i;
	for (i = MF-1; i >= 0; i--) {       /* starting from smallest we have */
		if (((!reverse) && (c[i].lst_mtime >= lst_mtime)) ||
		    ( reverse   && (c[i].lst_mtime <= lst_mtime)))       /* see if bigger */
			break;
		else {
			if ( i != (MF-1)) {         /* if it is, shuffle into place */
				c[i+1].lst_mtime = c[i].lst_mtime;
				memcpy(c[i+1].name, c[i].name, sizeof(c[i].name));
			}
		}
	}
	if ( i != (MF-1)) {                 /* final test for top of tree */
		c[i+1].lst_mtime = lst_mtime;
		memcpy(c[i+1].name, fname, sizeof(c[i].name));
	}
}

void tree(char *root) {                 /* Process a unix directory */
	DIR             *dirp;
	struct dirent   *dp;
	struct stat     s;
	char            buf[FNLEN];
	int				rlen;

	dirp = opendir(root);       /* Open top of the directory tree */
	rlen = strlen(root);
	if (dirp == NULL)
		return;                 /* cannot open */
	while ((dp = readdir(dirp)) != NULL) { /* process entries in directory */
		if (strcmp(dp->d_name, ".") == 0)
			continue;           /* don't go infinite */
		if (strcmp(dp->d_name, "..") == 0)
			continue;           /* don't go infinite */
		if ((rlen + strlen(dp->d_name)) >= sizeof(buf)) {
			fprintf(stderr,"%s:%d: buffer length exceeded\n%s/%s\n",
					__FILE__, __LINE__, root, dp->d_name);
			continue;
		}
		sprintf(buf,"%s/%s", root, dp->d_name);
		if (do_trace) {
			printf("[%s]\n", buf);
		}
		if (follow) {
			if (stat(buf, &s)) {
				continue;           /* no data available */
			}
		} else {					/* not following the link */
			if (lstat(buf, &s)) {
				continue;           /* no data available */
			}
		}
		switch (device_mode) {
		case 's':
			device = s.st_dev;
			device_mode = 'S';
			break;
		case 'S':
			if (s.st_dev != device) {
				continue;
			}
			break;
		default:
			break;
		}
		if ( !follow && S_ISLNK(s.st_mode)) {
			;           /* don't go down at sym linked directories */
		} else {
			if (S_IFDIR & s.st_mode) {
				tree(buf);          /* go down subdirectory */
			}
		}
		if ((S_IFREG & s.st_mode) == 0) {
			continue;           /* only look at regular files */
		}
		/* Check for matching against particular UID/GID */

		if ((uid >= 0) && (uid != s.st_uid))
			continue;
		if ((gid >= 0) && (gid != s.st_gid))
			continue;

		/* Grap the requested file date, modification/status/access */
		switch (st_time) {
		case 'c':
			big(s.st_ctime, buf);    /* See if big file or not */
			break;
		case 'a':
			big(s.st_atime, buf);    /* See if big file or not */
			break;
		case 'm':
		default:
			big(s.st_mtime, buf);    /* See if big file or not */
			break;
		}
	}
	(void) closedir(dirp);
}

static char Copyright[] = "@(#) Copyright 1994, David Horton";
static char rcs[] = "@(#)$RCSfile$ $Revision$";

void main(int argc, char *argv[]) {
	int		arg;
	int             i;
	int             many = MF;
	char		when[100];
	int		dirs = 0;
	struct passwd *pwent = NULL;
	struct group *grent = NULL;

	memset(c, 0, sizeof(c));

	for(arg = 1; arg < argc; arg++) {
		if ((strcmp(argv[arg], "/?") == 0) ||
		    (strcmp(argv[arg], "-h") == 0)) {
			printf("Usage: %s [-r] [-nn] [-{m|a|c}] [-u username] [-g groupname] [-f] [-t] [directory...]\nWhere nn is number of files reported\n",
				argv[0]);
			continue;
		}
		if (argv[arg][0] == '-') {
			switch(argv[arg][1]) {
			case 'r': case 'R':
				reverse = 'r';
				for(i = 0; i < MF; i++)
					c[i].lst_mtime = DISTANT;
				continue;
			case 'm': case 'M':		/* last modification time */
				st_time = 'm';
				continue;
			case 'a': case 'A':		/* last access time */
				st_time = 'a';
				continue;
			case 'c': case 'C':		/* last status change */
				st_time = 'c';
				continue;
			case 'd': case 'D':
				nodate = 'd';
				continue;
			case 'u': case 'U':
				if ((pwent = getpwnam(argv[++arg])) != NULL) {
					uid = pwent->pw_uid;
				} else {
					perror(argv[arg]);
					exit (errno);
				}
				break;
			case 'g': case 'G':
				if ((grent = getgrnam(argv[++arg])) != NULL) {
					gid = grent->gr_gid;
				} else {
					perror(argv[arg]);
					exit (errno);
				}
				break;
			case 's': case 'S':
				device_mode = 's';
				break;
			case 'v':
				fprintf(stderr, "%s : %s\n",argv[0], Copyright);
				fprintf(stderr, "%s\n", rcs);
				exit(0);
				break;
			case 'f': case 'F':		/* follow sym links */
				follow = 'F';
				continue;
			case 't': case 'T':		/* debug trace*/
				do_trace = 'Y';
				setbuf(stdout, NULL);
				continue;
			default:
				many = - atoi(argv[arg]);
				if ((many == 0) || (many > MF))
					many = MF;
				continue;
			}
		}
		tree(argv[arg]);
		dirs ++;
	}
	if(dirs == 0)
		tree(".");
	/* report the findings */
	for(i = 0; i < many; i++) {
		if((c[i].lst_mtime == 0) || (c[i].lst_mtime == DISTANT))
			break;
		if(nodate) {
			printf("%s\n", c[i].name);
		} else {
 			(void) strftime(when, sizeof(when), 
				"%d-%b-%y %H:%M:%S", localtime(&c[i].lst_mtime));
 			printf("%20s  %s\n", when, c[i].name);
		}
	}
	exit(0);
}