/*
 * bb.c
 * kreator, 1999.
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/file.h>
#include <errno.h>
#include <time.h>

#define BBFILENAME "/DATA"
#define TMPFILE "/tmp/bb.tmp"

int add_luser (char *luser);
int find_luser (char *luser);
int display_help (char *bbname);
extern char *strncat (char *, const char *, size_t);
extern char *strcat (char *, const char *);
extern char *strncpy (char *, const char *, size_t);
extern int strncmp (const char *, const char *, size_t);
extern char *strstr (const char *, const char *);

int main(int argc, char *argv[])
{
	/* better safe than sorry */	
	umask(077);

	if (!geteuid() || !getuid())
		fprintf(stderr, "NOTICE: You are running BB as root\n\n");
	
	/* parse argv, lousy :-( */
	if (argc>1)
	{
		if (argc>2 && *argv[2]=='-') add_luser(argv[1]);
			else find_luser(argv[1]);
	}
	else
	display_help(argv[0]);

	return EXIT_SUCCESS;
}

int add_luser(char *luser)
{
	int fd, fdtmp, len;
	char *editor, cmdline[512], *asctime;
	void *buffptr;
        struct stat statbuf, statbuf2;
	time_t timeofday;

	/* time is _required_! */
	if ((timeofday=time(NULL))==-1)
	{
		fprintf(stderr, "ERROR: Clock Failure (%d)\n", 
				errno);
		exit(errno);
	}
	asctime=ctime(&timeofday);

	/* get editor */
	if (((editor=getenv("EDITOR"))==NULL) 
			&& ((editor=getenv("VISUAL"))==NULL))
	{
		fprintf(stderr, "ERROR: Undefined editor\n");
		exit(EXIT_FAILURE);
	}

	/* if there is write-protected tmpfile! */
	unlink(TMPFILE);

	/* open tmpfile, append @@@ delimiter, user and date. */
        if ((fdtmp=open(TMPFILE, O_WRONLY|O_CREAT, 
					S_IRUSR|S_IWUSR))==-1)
	{
		fprintf(stderr,
			"ERROR: Failure opening TMP file (%d)\n", 
				errno);
		exit(errno);
	}
	/* construct info string */
	memcpy(cmdline, "@@@\n", 6);
	strncat(cmdline, luser, 8);
	strcat(cmdline, "\n");
	strcat(cmdline, asctime);
	strcat(cmdline, "\n");
	if (write(fdtmp, cmdline, strlen(cmdline))==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure writing to TMP file (%d)\n",
				errno);
		exit(errno);
	}
	if (fstat(fdtmp, &statbuf2)==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure getting TMP file status (%d)\n",
				errno);
		exit(errno);
	}
	close(fdtmp);

	/* construct command line, system-it.. */
	if ((len=strlen(editor))>256)
	{
		fprintf(stderr, 
			"ERROR: Check your EDITOR/VISUAL variable\n");
		exit(EXIT_FAILURE);
	}
	memcpy(cmdline, editor, len+1);
	strcat(cmdline, " +4 ");
	strcat(cmdline, TMPFILE);
	system(cmdline);

	/* ...then get its size and append it to blackbook file */
	if (stat(TMPFILE, &statbuf)==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure getting file status (%d)\n",
				errno);
		exit(errno);
	}
	if (!(statbuf2.st_size-statbuf.st_size))
	{
		fprintf(stderr, "ERROR: Zero-size comment file\n");
		exit(EXIT_FAILURE);
	}
	if ((buffptr=malloc(statbuf.st_size))==NULL)
	{
		fprintf(stderr, 
			"ERROR: Failure allocating memory (%d)\n",
				errno);
		exit(errno);
	}
        if ((fdtmp=open(TMPFILE, O_RDONLY, S_IRUSR|S_IWUSR))==-1)
	{
		fprintf(stderr,
			"ERROR: Failure opening TMP file (%d)\n",
				errno);
		exit(errno);
	}
	if (read(fdtmp, buffptr, statbuf.st_size)==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure reading TMP file (%d)\n", 
				errno);
		exit(errno);
	}
	close(fdtmp);
	unlink(TMPFILE);

	/* open blackbook file */
	if ((fd=open(BBFILENAME, O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR))==-1)
        {
		fprintf(stderr,
			"ERROR: Failure opening blackbook file (%d)\n",
				errno);
		exit(errno);
	}

	/* lock it and make it available only to this process */
/*flock(fd, LOCK_EX); */

	if (write(fd, buffptr, statbuf.st_size)==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure appending to blackbook file (%d)\n",
				errno);
		exit(errno);
	}

	/* unlock file */	
/*	flock(fd, LOCK_UN); */

	/* close, free and exit */
	close(fd);
	free(buffptr);
	return EXIT_SUCCESS;
}

int find_luser(char *luser)
{
	int fd, len, lamercounter=0;
	caddr_t mmapptr, currptr, maxptr;
	struct stat statbuf;
	char *buff=NULL, *delimpos;
	char lzr[10];
	size_t memsz;

	/* open file */
        if ((fd=open(BBFILENAME, O_RDONLY, S_IRUSR|S_IWUSR))==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure opening blackbook file (%d)\n", 
				errno);
		exit(errno);
	}

	/* get its stats */
	if (fstat(fd, &statbuf)==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure getting blackbook file status (%d)\n",
				errno);
		exit(errno);
	}

	/* map it into memory */
	if ((mmapptr=mmap(0, statbuf.st_size, PROT_READ, 
		MAP_SHARED, fd, 0))==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure mapping file into memory (%d)\n", 
				errno);
		exit(errno);
	}

	/* finding and printing code */
	maxptr=mmapptr+statbuf.st_size;
	strncpy(lzr, luser, 9);
	strcat(lzr, "\n");
	len=strlen(lzr);
	for (currptr=mmapptr; currptr+35<maxptr; ++currptr)
	{
		if (!strncmp(currptr, "@@@\n", 4))
		{
			if (!strncmp(currptr+4, lzr, len))
			{
				if ((delimpos=strstr(currptr+4, 
					"\n@@@\n"))==NULL) delimpos=maxptr;
				if ((buff=realloc(buff, 
					memsz=delimpos-currptr-len-2))==NULL)
				{
					fprintf(stderr,
				"ERROR: Failure allocating memory (%d)\n", 
					errno);
					exit(errno);
				}
				memcpy(buff, currptr+len+4, memsz);
				*(buff+memsz-1)=0;
				puts(buff);
				++lamercounter;
			}
		}
	}
	if (lamercounter) 
		fprintf(stdout, 
			"----=---- Luser has been %d times in blackbook\n", 
				lamercounter);
	else
		fprintf(stderr, "ERROR: No such user in blackbook\n");

	/* unmap it and close */	
	if (munmap(mmapptr, statbuf.st_size)==-1)
	{
		fprintf(stderr, 
			"ERROR: Failure unmapping file (%d)\n",
				errno);
	}
	close(fd);
	free(buff);

	return EXIT_SUCCESS;
}

int display_help(char *bbname)
{
	fprintf(stdout, "%s usage:
bb <username>\t\tgives blackbook entry on given user
bb <username> -\tmakes a blackbook entry on given user\n",
			bbname);
	return EXIT_SUCCESS;
}