/* $Id: init.c,v 3.21 2008/11/17 18:59:05 ksb Exp $
 * build a linked list of all the files entombed for this user.   (becker)
 * use the table of filesystem names generated by "fslist." 
 */
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <stdlib.h>

#include "machine.h"
#include "libtomb.h"
#include "machine.h"

#include "lists.h"
#include "init.h"
#include "main.h"
#include "fslist.h"

#if USE_STRINGS
#include <strings.h>
#else
#include <string.h>
#endif

#if HAVE_NDIR
#include <ndir.h>
#else
#if HAVE_DIRENT
#include <dirent.h>
#else
#include <sys/dir.h>
#endif
#endif

#if USE_SYSEXITS_H
#include <sysexits.h>
#else
#define EX_SOFTWARE	99
#endif

#if USE_STDLIB_H
#include <stdlib.h>
#else
#if USE_MALLOC_H
#include <malloc.h>
#else
extern char *malloc();
#endif
#endif

#if !HAVE_STRERROR
extern char *sys_errlist[];
#define strerror(Me) (sys_errlist[Me])
#endif

#if !defined(MODDOTS)
#define MODDOTS	(10)		/* a dot for every 10 files	*/
#endif



/* functions defined in and local to this file */
static time_t remove_date();
static int datecmp();


char acUid[16] = {"-1"};
int iUserUid = -1;
int iUserGid = -1;
int iTombUid = -1;
int iTombGid = -1;

LE *pLEFilesList = nilLE;

extern void original();

static TombInfo *pTIHead = (TombInfo *)0;
static int tInit = 0;

/* setup the runtime structures
 */
void
Init(fDots)
int fDots;		/* to dot or not to dot				*/
{
	static char acTombedFile[MAXPATHLEN+MAXNAMLEN+1], *pchFileStart;
	static char acUTombDir[MAXPATHLEN];
	register TombInfo *pTI;
	register int iDots = 0;
	register DIR *pD;
	register LE *pLE;
	register struct DIRENT *pdEntry;
	auto struct stat statBuf;


	if (tInit) {
		return;
	}
	tInit = 1;

	if (-1 == (iUserUid = getuid())) {
		(void)fprintf(stderr, "%s: getuid: %s\n", progname, strerror(errno));
		exit(1);
	}
	if (-1 == (iUserGid = getgid())) {
		(void)fprintf(stderr, "%s: getgid: %s\n", progname, strerror(errno));
		exit(1);
	}
	if (-1 == (iTombUid = geteuid())) {
		(void)fprintf(stderr, "%s: geteuid: %s\n", progname, strerror(errno));
		exit(1);
	}
	if (-1 == (iTombGid = getegid())) {
		(void)fprintf(stderr, "%s: getegid: %s\n", progname, strerror(errno));
		exit(1);
	}
	(void)sprintf(acUid, "%d", iUserUid);


	/* get the list of filesystems		*/
	pTIHead = FsList(iTombGid, NOT_A_DEV);

	/*
	 * zip through the array of filesystem names, opening our tomb
	 * directory in each, and adding the entombed files we find there to
	 * the linked list.
	 */

	if (Verbose && fDots) {
		(void)fprintf(stdout, "(Reading tombs; please wait...");
		(void)fflush(stdout);
	}

	for (pTI = pTIHead; (TombInfo *)0 != pTI; pTI = pTI->pTINext) {
		register int iErr;

		(void)strcpy(acUTombDir, pTI->pcDir);
		(void)strcat(acUTombDir, "/");
		(void)strcat(acUTombDir, acUid);
		/* become charon to look at the tomb, if he can't
		 * try the original
		 */
		charon();
		pD = opendir(acUTombDir);
		if ((DIR *)0 == pD) {
			if (ENOENT == errno) {
				continue;
			}
#if DEBUG
			(void)fprintf(stderr, "%s: effective %d.%d, real %d.%d\n", progname, geteuid(), getegid(), getuid(), getgid());
#endif
			/* the user may have removed no files on this filesys
			 */
			original();
			pD = opendir(acUTombDir);
			iErr = errno;
			charon();
			/* something is wrong, we can't read the tomb,
			 * we're probably not setuid, or it just got rmdir'd
			 */
			if ((DIR *)0 == pD) {
				if (ENOENT == iErr)
					continue;
				(void)fprintf(stderr, "\n%s: Internal error: can't open tomb `%s\': %s\n", progname, acUTombDir, strerror(errno));
				(void)fprintf(stderr, "%s: Seek assistance from a system admin\n", progname);
				(void)fprintf(stderr, "%s: Possible NFS or uid/gid mapping problem.\n", progname);
				(void)fprintf(stderr, "%s: effective %d.%d, real %d.%d\n", progname, geteuid(), getegid(), getuid(), getgid());
				(void)fflush(stderr);
				exit(45);
			}
		}

#if USE_CLOSE_ON_EXEC
		/* This prevents forked children from reading the crypt
		 * (no call in this loop forks, so we really don't need it).
		 */
#if EMU_DIRFD
#if !defined(dirfd)
#define dirfd(dirp)	((dirp)->dd_fd)
#endif
#endif

		if (-1 == fcntl(dirfd(pD), F_SETFD, 0x01)) {
			(void)fprintf(stderr, "%s: fcntl: %s\n", progname, strerror(errno));
			exit(1);
		}
#endif
		(void)strcpy(acTombedFile, acUTombDir);
		(void)strcat(acTombedFile, "/");
		pchFileStart = acTombedFile + strlen(acTombedFile);

		while ((struct DIRENT *)0 != (pdEntry = readdir(pD))) {
			acUTombDir[0] = '\000';

			/* ignore deleted files */
			if (0 == pdEntry->d_ino)
				continue;
			if (0 == strcmp("..", pdEntry->d_name))
				continue;
			if (0 == strcmp(".", pdEntry->d_name))
				continue;
			(void) strcat(acUTombDir, pdEntry->d_name);
			(void) strcpy(pchFileStart, pdEntry->d_name);
			if (stat(acTombedFile, &statBuf) < 0) {
				(void)fprintf(stderr, "%s: stat: %s: %s\n", progname, acTombedFile, strerror(errno));
			}
			if (Verbose && fDots && MODDOTS == ++iDots) {
				putchar('.');
				(void)fflush(stdout);
				iDots = 0;
			}

			pLE = newLE();
			pLE->next = nilLE;
			pLE->size = statBuf.st_size;
			pLE->date = remove_date(acUTombDir);
			pLE->pTI = pTI;
			pLE->mark = 0;
			pLE->name = malloc((unsigned)strlen(acUTombDir)+1);
			if (NULL == pLE->name) {
				exit(12);	/*ENOMEM*/
			}
			(void) strcpy(pLE->name, acUTombDir);

			SLInsert(& pLEFilesList, pLE, datecmp);
		}
		(void)closedir(pD);
	}

	if (Verbose && fDots) {
		(void)fprintf(stdout, "done)\n");
		(void)fflush(stdout);
	}
}

/* show the user which tombs we see					(ksb)
 */
void
ShowTombs(fp)
FILE *fp;
{
	register TombInfo *pTI;

	if (! tInit) {
		Init(DOTS_NO);
	}
	for (pTI = pTIHead; (TombInfo *)0 != pTI; pTI = pTI->pTINext) {
		fprintf(fp, "%s: tomb: %s\n", progname, pTI->pcDir);
	}
}

/* show the use which crypts we see in the tombs we see			(ksb)
 */
void
ShowCrypts(fp)
FILE *fp;
{
	register TombInfo *pTI;
	auto char acCrypt[MAXPATHLEN+1];
	auto struct stat stCrypt;

	if (! tInit) {
		Init(DOTS_NO);
	}
	for (pTI = pTIHead; (TombInfo *)0 != pTI; pTI = pTI->pTINext) {
		sprintf(acCrypt, "%s/%s", pTI->pcDir, acUid);
		if (0 != stat(acCrypt, & stCrypt)) {
			continue;
		}
		fprintf(fp, "%s: crypt: %s\n", progname, acCrypt);
	}
}


static int
datecmp(pLElist, pLEelem)
LE *pLElist, *pLEelem;
{
	return pLEelem->date - pLElist->date;
}


/* for use [for instance] when joe user types  "restore foo"		(ksb)
 * to translate the "foo" into "/usera/tomb/joe/foo@23432423".
 *	pLE = Retrieve(pLEFilesList, namecmp, pchFile);
 *	pcBuf = ac1024;
 * NB: should be in lists.c
 */
char *
real_name(pcBuf, pLE)
char *pcBuf;
register LE *pLE;
{
	if (NULL == pLE) {
		return NULL;
	}
	
	(void)sprintf(pcBuf, "%s/%s/%s@%d", pLE->pTI->pcDir, acUid, pLE->name, pLE->date);
	return pcBuf;
}


/*
 * remove_date - takes a file name of the form <file>@<numericdate>,	(mjb)
 *	replaces the '@' with \0, and returns the time_t associated
 *	with <numericdate>.
 */
static time_t
remove_date(pcFile)
char *pcFile;
{
	register char *pc;

	if (NULL == (pc = strrchr(pcFile, '@'))) {
		/* return Jan 1 1970 for mis-formed filenames	*/
		return 0;
	}
	*pc = '\000';
	return (time_t)atol(pc + 1);
}


/* revoke our super powers for all time					(ksb)
 */
void
drop()
{
#if USE_SAVED_UID
	if (iTombUid != iUserUid) {
		setuid(iUserUid);
	}
	if (iTombGid != iUserGid) {
		setgid(iUserGid);
	}
#else
	if (iTombUid != iUserUid || 0 == iUserUid) {
		(void)setuid(iUserUid);
	}
	if (iTombGid != iUserGid || 0 == iUserUid || 0 == iTombUid) {
		(void)setgid(iUserGid);
	}
#endif
}

/* change effective group to charon				     (becker)
 * real `joe.group', effective `???.charon'
 */
void
charon()
{
#if USE_SAVED_UID
	/* if we drop from root we cannot get back...
	 */
	if (0 != iUserUid) {
		setuid(iTombUid);
	}
	setgid(iTombGid);
#else
	/* if we can become charon and still get back to joe, do it
	 */
	if (0 == iTombUid || TOMB_UID == iTombUid || 0 == iUserUid) {
		(void)setreuid(iUserUid, TOMB_UID);
	} else if (iTombUid != iUserUid) {
		(void)setreuid(iUserUid, iTombUid);
	}
	/* if we can be group charon, do it
	 */
	if (0 == iTombUid || TOMB_GID == iTombGid || 0 == iUserUid) {
		(void)setregid(iUserGid, TOMB_GID);
	} else if (-1 == setregid(iUserGid, iTombGid)) {
		fprintf(stderr, "%S: setregid: %s\n", progname, strerror(errno));
		exit(NOT_ENTOMBED);
	}
#endif
}


/* change effective group to the user				     (becker)
 * real `???.charon', effective `joe.group'
 */
void
user()
{
#if USE_SAVED_UID
	setgid(iUserGid);
	setuid(iUserUid);
#else
	if (iTombUid != iUserUid || 0 == iUserUid) {
		(void)setreuid(iTombUid, iUserUid);
	}
	if (-1 == setregid(iTombGid, iUserGid)) {
		fprintf(stderr, "%s: setregid: %s\n", progname, strerror(errno));
		exit(NOT_ENTOMBED);
	}
#endif
}

/* change effective user to root for chown, if we can			(ksb)
 * real `root.group', effective `root.charon'
 */
int
root()
{
	register int iRet = -1;

	if (0 == iTombUid || 0 == iUserUid) {
		iRet = setuid(0);
	}
#if USE_SAVED_UID
	(void)setgid(iTombGid);
#else
	(void)setregid(iUserGid, iTombGid);
#endif
	return iRet;
}

/* change back to the original calling effective/real user/group	(ksb)
 * real `joe.group', effective `???.charon'
 */
void
original()
{
#if USE_SAVED_UID
	(void)setgid(iUserGid);
	(void)setuid(iUserUid);
#else
	if (-1 == setreuid(iTombUid, iUserUid)) {
		fprintf(stderr, "%s: setreuid: %s\n", progname, strerror(errno));
		exit(1);
	}
	if (-1 == setregid(iTombGid, iUserGid)) {
		fprintf(stderr, "%s: setregid: %s\n", progname, strerror(errno));
		exit(1);
	}
#endif
}